Optical components and lighting devices

Abstract

An optical element is provided that can control the light distribution or light distribution pattern. An optical element includes two stacked liquid crystal cells (120, 110), wherein each liquid crystal cell includes: a first substrate (111-1, 121-1) having a first transparent electrode (112-1, 122-1) and a second transparent electrode (112-2, 122-2) alternately disposed along a first direction; a second substrate (111-2, 121-2) having a third transparent electrode (112-3, 122-3) and a fourth transparent electrode alternately disposed along a second direction intersecting the first direction; and a liquid crystal layer (113, 123) located between the first substrate and the second substrate, wherein the second substrate (111-2) of one liquid crystal cell is adjacent to the first substrate (121-1) of the other liquid crystal cell.

Description

Technical Field

[0001] One embodiment of the present invention relates to an optical element capable of controlling light distribution. Another embodiment of the present invention relates to an illumination device comprising an optical element capable of controlling light distribution. Background Technology

[0002] Previously, an optical element known as a liquid crystal lens was developed that utilized the change in the refractive index of a liquid crystal by adjusting the voltage applied to it. Furthermore, development is underway for illumination devices using a light source and a liquid crystal lens (see, for example, Patent Document 1, Patent Document 2, or Patent Document 3).

[0003] Existing technical documents

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2005-317879

[0006] Patent Document 2: Japanese Patent Application Publication No. 2010-230887

[0007] Patent Document 3: Japanese Patent Application Publication No. 2014-160277 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] However, the lighting devices described in Patent Document 1 or Patent Document 2 are only intended to focus light by controlling the diffusion distribution of light, i.e., the light distribution angle, using a liquid crystal lens. In other words, the light distribution pattern in the lighting devices described in Patent Document 1 or Patent Document 2 is limited to concentric circles. Furthermore, the beam shaping device described in Patent Document 3 requires a complex liquid crystal cell to change the light distribution pattern by altering the pattern of the electrodes applied to the liquid crystal, thus lacking mass production capability.

[0010] In view of the above problems, one objective of one embodiment of the present invention is to provide an optical element capable of controlling the light distribution or light distribution pattern. Another objective of one embodiment of the present invention is to provide an illumination device capable of controlling the light distribution or light distribution pattern.

[0011] Technical solutions for solving the problem

[0012] An embodiment of the present invention relates to an optical element comprising two stacked liquid crystal cells, wherein each liquid crystal cell comprises: a first substrate having a first transparent electrode and a second transparent electrode alternately disposed along a first direction; a second substrate having a third transparent electrode and a fourth transparent electrode alternately disposed along a second direction intersecting the first direction; and a liquid crystal layer located between the first substrate and the second substrate, wherein the second substrate of one liquid crystal cell is adjacent to the first substrate of the other liquid crystal cell.

[0013] In addition, one embodiment of the present invention relates to a lighting device including a light source and the optical element. Attached Figure Description

[0014] Figure 1 This is a three-dimensional schematic diagram of an optical element according to one embodiment of the present invention.

[0015] Figure 2A This is a cross-sectional schematic diagram of an optical element according to one embodiment of the present invention.

[0016] Figure 2B This is a cross-sectional schematic diagram of an optical element according to one embodiment of the present invention.

[0017] Figure 3A This is a top view schematic diagram illustrating the configuration of a first transparent electrode and a second transparent electrode on a first substrate in an optical element according to an embodiment of the present invention.

[0018] Figure 3B This is a top view schematic diagram illustrating the configuration of a third transparent electrode and a fourth transparent electrode on a second substrate in an optical element according to an embodiment of the present invention.

[0019] Figure 4A This is a cross-sectional schematic diagram showing the orientation of the liquid crystal in the liquid crystal layer of an optical element according to an embodiment of the present invention.

[0020] Figure 4B This is a cross-sectional schematic diagram showing the orientation of the liquid crystal in the liquid crystal layer of an optical element according to an embodiment of the present invention.

[0021] Figure 5A This is a three-dimensional schematic diagram showing the orientation of liquid crystal molecules in a liquid crystal layer of an optical element according to an embodiment of the present invention when a voltage is applied.

[0022] Figure 5B This is a cross-sectional schematic diagram showing the orientation of liquid crystal molecules in a liquid crystal layer in an optical element according to an embodiment of the present invention when a voltage is applied.

[0023] Figure 5CThis is a cross-sectional schematic diagram showing the orientation of liquid crystal molecules in a liquid crystal layer in an optical element according to an embodiment of the present invention when a voltage is applied.

[0024] Figure 6A This is a cross-sectional schematic diagram illustrating the control of light distribution by an optical element according to one embodiment of the present invention.

[0025] Figure 6B This is a cross-sectional schematic diagram illustrating the control of light distribution by an optical element according to one embodiment of the present invention.

[0026] Figure 7A This is a timing diagram showing the voltage applied to each transparent electrode included in an optical element according to one embodiment of the present invention.

[0027] Figure 7B In one embodiment of the optical element according to the present invention, an application is made to each transparent electrode. Figure 7A A photograph of the light distribution pattern obtained by adjusting the potential shown.

[0028] Figure 8A This is a timing diagram showing the voltage applied to each transparent electrode included in an optical element according to one embodiment of the present invention.

[0029] Figure 8B In one embodiment of the optical element according to the present invention, an application is made to each transparent electrode. Figure 8A A photograph of the light distribution pattern obtained by adjusting the potential shown.

[0030] Figure 9A This is a timing diagram showing the voltage applied to each transparent electrode included in an optical element according to one embodiment of the present invention.

[0031] Figure 9B In one embodiment of the optical element according to the present invention, an application is made to each transparent electrode. Figure 9A A photograph of the light distribution pattern obtained by adjusting the potential shown.

[0032] Figure 10 This is a timing diagram showing the voltage applied to each transparent electrode included in an optical element according to one embodiment of the present invention.

[0033] Figure 11 This is a graph showing the relative brightness of the front side relative to d / p in a liquid crystal cell of an optical element according to one embodiment of the present invention.

[0034] Figure 12 This is a schematic diagram illustrating the configuration of a lighting device according to one embodiment of the present invention. Detailed Implementation

[0035] Hereinafter, various embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention can be implemented in various ways without departing from its technical spirit, and is not limited to the description of the embodiments shown in the following examples.

[0036] To make the description clearer, the width, thickness, shape, etc. of the parts in the drawings are sometimes shown schematically compared to the actual form. These are merely examples, and the shapes shown do not limit the interpretation of the invention. Furthermore, in the drawings, elements that have the same function as those described in the accompanying drawings are marked with the same reference numerals even in other drawings, and sometimes redundant descriptions are omitted.

[0037] When a single membrane is processed to form multiple structures, these structures may sometimes have different functions or roles. Furthermore, the substrates forming each structure may differ. However, these multiple structures originate from a membrane formed as the same layer in the same process and possess the same material. Therefore, these multiple membranes are defined as existing within the same layer.

[0038] When describing the configuration of other structures on top of a certain structure, the term "above" includes, unless otherwise specified, both cases where other structures are configured directly above a certain structure and cases where other structures are configured above a certain structure, separated by other structures.

[0039] <First Implementation Method>

[0040] Reference Figures 1 to 11 The optical element 10 according to one embodiment of the present invention will be described.

[0041] [1. Composition of optical elements]

[0042] Figure 1 This is a perspective view of an optical element 10 according to one embodiment of the present invention. Figure 1 As shown, the optical element 10 includes a first liquid crystal unit 110, a second liquid crystal unit 120, and an optical elastic resin layer 130. The optical elastic resin layer 130 is disposed between the first liquid crystal unit 110 and the second liquid crystal unit 120. That is, the first liquid crystal unit 110 and the second liquid crystal unit 120 are stacked along the z-axis in such a way that the optical elastic resin layer 130 is sandwiched in the middle.

[0043] The optical elastic resin layer 130 can bond and fix the first liquid crystal cell 110 and the second liquid crystal cell 120. As the optical elastic resin layer 130, an optical elastic resin can be used, such as an adhesive including an acrylic resin that is light-transmitting.

[0044] Figure 2A and Figure 2B This is a cross-sectional schematic diagram of an optical element 10 according to one embodiment of the present invention. Specifically, Figure 2A It is along Figure 1 The diagram shows a cross-sectional view of the zx plane obtained by cutting along line A1-A2. Figure 2B It is along Figure 1 The diagram shows a cross-sectional view of the yz plane obtained by cutting along line B1-B2. Furthermore, the x-axis and y-axis directions are sometimes referred to as the first direction and the second direction, respectively, below.

[0045] The first liquid crystal unit 110 includes a first substrate 111-1, a second substrate 111-2, a first transparent electrode 112-1, a second transparent electrode 112-2, a third transparent electrode 112-3, a fourth transparent electrode 112-4, a liquid crystal layer 113, a first alignment film 114-1, a second alignment film 114-2, and a sealing material 115. The second liquid crystal unit 120 includes a first substrate 121-1, a second substrate 121-2, a first transparent electrode 122-1, a second transparent electrode 122-2, a third transparent electrode 122-3, a fourth transparent electrode 122-4, a liquid crystal layer 123, a first alignment film 124-1, a second alignment film 124-2, and a sealing material 125.

[0046] The optical element 10 has two liquid crystal units, preferably with the same configuration. Therefore, for convenience, the configuration of the first liquid crystal unit 110 will sometimes be described only, while the configuration of the second liquid crystal unit 120 will be omitted.

[0047] A first transparent electrode 112-1 and a second transparent electrode 112-2 are disposed on the first substrate 111-1. In addition, a first alignment film 114-1 is disposed to cover the first transparent electrode 112-1, the second transparent electrode 112-2 and the surface of the first substrate 111-1.

[0048] A third transparent electrode 112-3 and a fourth transparent electrode 112-4 are disposed on the second substrate 111-2. In addition, a second alignment film 114-2 is disposed to cover the third transparent electrode 112-3, the fourth transparent electrode 112-4 and the surface of the second substrate 111-2.

[0049] The first substrate 111-1 and the second substrate 111-2 are configured such that the first transparent electrode 112-1 and the second transparent electrode 112-2 on the first substrate 111-1 are opposite to the third transparent electrode 112-3 and the fourth transparent electrode 112-4 on the second substrate 111-2.

[0050] Furthermore, a sealing material 115 is disposed at the periphery of each of the first substrate 111-1 and the second substrate 111-2. That is, the first substrate 111-1 and the second substrate 111-2 are bonded together by the sealing material 115. In addition, liquid crystal is sealed in the space surrounded by the first substrate 111-1 (more specifically, the first alignment film 114-1), the second substrate 111-2 (more specifically, the second alignment film 114-2), and the sealing material 115 to form a liquid crystal layer 113.

[0051] The first substrate 111-1 and the second substrate 111-2 are respectively made of rigid substrates that are transparent to light, such as glass substrates, quartz substrates, or sapphire substrates. Alternatively, the first substrate 111-1 and the second substrate 111-2 may also be made of flexible substrates that are transparent to light, such as polyimide resin substrates, acrylic resin substrates, silicone resin substrates, or fluoropolymer substrates.

[0052] The first transparent electrode 112-1, the second transparent electrode 112-2, the third transparent electrode 112-3, and the fourth transparent electrode 112-4 function as electrodes for forming an electric field in the liquid crystal layer 113. The first transparent electrode 112-1, the second transparent electrode 112-2, the third transparent electrode 112-3, and the fourth transparent electrode 112-4 are made of transparent conductive materials such as indium tin oxide (ITO) or indium zinc oxide (IZO).

[0053] The liquid crystal layer 113 can refract or change the polarization state of transmitted light depending on the orientation state of the liquid crystal molecules. For example, a nematic liquid crystal can be used as the liquid crystal layer 113. In this embodiment, a positive liquid crystal is used, but it can also be configured to be negative by changing the initial orientation direction of the liquid crystal molecules. Furthermore, it is preferable that the liquid crystal contains a chiral agent that imparts twisting to the liquid crystal molecules.

[0054] The first alignment film 114-1 and the second alignment film 114-2 align the liquid crystal molecules within the liquid crystal layer 113 along a predetermined direction. The first alignment film 114-1 and the second alignment film 114-2 can each be made of, for example, polyimide resin. Furthermore, the first alignment film 114-1 and the second alignment film 114-2 can also be endowed with alignment characteristics through alignment treatments such as rubbing or photoalignment. Rubbing is a method of rubbing the surface of the alignment film in one direction. Photoalignment involves irradiating the alignment film with linearly polarized ultraviolet light.

[0055] The sealing material 115 bonds and fixes the first substrate 111-1 and the second substrate 111-2 together. For example, epoxy resin adhesive or acrylic resin adhesive can be used as the sealing material 115. The adhesive can be UV-curable or thermosetting.

[0056] The optical element 10, by comprising two liquid crystal units (a first liquid crystal unit 110 and a second liquid crystal unit 120), can control the distribution of unpolarized light and form a light distribution pattern, as will be described in detail later. Therefore, it is not necessary to provide a pair of polarizers, such as those provided on the back surface of the liquid crystal display element, on the outer surface of each substrate.

[0057] [2. Configuration of transparent electrodes]

[0058] Reference Figure 3A and Figure 3B The configurations of the first transparent electrode 112-1, the second transparent electrode 112-2, the third transparent electrode 112-3, and the fourth transparent electrode 112-4 are described in detail.

[0059] Figure 3A This is a top view schematic diagram showing the arrangement of a first transparent electrode 112-1 and a second transparent electrode 112-2 on a first substrate 111-1 in an optical element 10 according to one embodiment of the present invention. Additionally, Figure 3B This is a top view schematic diagram showing the arrangement of the third transparent electrode 112-3 and the fourth transparent electrode 112-4 on the second substrate 111-2 in an optical element 10 according to one embodiment of the present invention. Furthermore, Figure 3A and Figure 3B The configuration of each transparent electrode as seen from the first liquid crystal layer 115-1 side is shown.

[0060] like Figure 3AAs shown, the first transparent electrode 112-1 and the second transparent electrode 112-2 each have a first width a1 in the x-axis direction and extend along the y-axis direction. Furthermore, the first transparent electrode 112-1 and the second transparent electrode 112-2 have a first inter-electrode distance b1 in the x-axis direction and are alternately arranged. That is, the first transparent electrode 112-1 and the second transparent electrode 112-2 have a first pitch p1, and p1 = a1 + b1. Additionally, the first transparent electrode 112-1 and the second transparent electrode 112-2 are electrically connected to a first wiring 116-1 and a second wiring 116-2 formed on the first substrate 111-1, respectively. The first wiring 116-1 can be formed below or above the first transparent electrode 112-1. In this case, the first wiring 116-1 can also be formed of metal. Alternatively, the first wiring 116-1 can also be formed in the same layer as the first transparent electrode 112-1. The second wiring 116-2 is formed similarly.

[0061] The first alignment film 114-1 is aligned along the x-axis. In this case, the long axis of the liquid crystal molecules on the first substrate 111-1 side of the liquid crystal molecules constituting the liquid crystal layer 113 is aligned along the x-axis in the absence of an electric field. That is, the alignment direction (x-axis direction) of the first alignment film 114-1 is orthogonal to the extension direction (y-axis direction) of the first transparent electrode 112-1 or the second transparent electrode 112-2. Furthermore, alignment processes based on friction or light alignment can be cited as examples. In addition, the alignment directions of the first alignment film 114-1 and the second alignment film 114-2 only need to be orthogonal to each other, and their respective alignment directions can also intersect the extension direction of the transparent electrode on which the first alignment film 114-1 or the second alignment film 114-2 is disposed at an angle other than a right angle.

[0062] like Figure 3BAs shown, the third transparent electrode 112-3 and the fourth transparent electrode 112-4 each have a second width a2 in the y-axis direction and extend along the x-axis direction. Furthermore, the third transparent electrode 112-3 and the fourth transparent electrode 112-4 have a second inter-electrode distance b2 in the y-axis direction and are alternately arranged. That is, the third transparent electrode 112-3 and the fourth transparent electrode 112-4 have a second pitch p2, and p2 = a2 + b2. Additionally, the third transparent electrode 112-3 and the fourth transparent electrode 112-4 are electrically connected to the third wiring 116-3 and the fourth wiring 116-4 formed on the second substrate 111-2, respectively. The third wiring 116-3 and the fourth wiring 116-4 can be formed below or above the third transparent electrode 112-3 and the fourth transparent electrode 112-4. In this case, the third wiring 116-3 and the fourth wiring 116-4 can also be formed of metal. Alternatively, the third wiring 116-3 and the fourth wiring 116-4 may also be formed in the same layer as the third transparent electrode 112-3 and the fourth transparent electrode 112-4.

[0063] The second alignment film 114-2 is aligned along the y-axis. In this case, the long axis of the liquid crystal molecules on the second substrate 111-2 side of the liquid crystal molecules constituting the liquid crystal layer 113 is aligned along the y-axis in the absence of an electric field. That is, the alignment direction (y-axis direction) of the second alignment film 114-2 is orthogonal to the extension direction (x-axis direction) of the third transparent electrode 112-3 or the fourth transparent electrode 112-4.

[0064] Furthermore, the first transparent electrode 112-1 and the second transparent electrode 112-2 can also be formed on the first substrate 111-1 in a comb-like pattern with a first pitch p1. Similarly, the third transparent electrode 112-3 and the fourth transparent electrode 112-4 can also be formed on the second substrate 111-2 in a comb-like pattern with a second pitch p2.

[0065] In the first liquid crystal cell 110, the first transparent electrode 112-1 and the second transparent electrode 112-2 are positioned opposite the third transparent electrode 112-3 and the fourth transparent electrode 112-4 across the liquid crystal layer 113. Here, the extending directions (y-axis direction) of the first transparent electrode 112-1 and the second transparent electrode 112-2 are orthogonal to the extending directions (x-axis direction) of the third transparent electrode 112-3 and the fourth transparent electrode. In other words, the comb-shaped electrode pattern formed on the first substrate 111-1 is orthogonal to the comb-shaped electrode pattern formed on the second substrate when viewed from above. Furthermore, a fifth wiring 116-5 and a sixth wiring 116-6 are formed on the first substrate 111-1. When the first substrate 111-1 and the second substrate 111-2 are bonded together, the third wiring 116-3 and the fourth wiring 116-4 are electrically connected to the fifth wiring 116-5 and the sixth wiring 116-6 disposed on the first substrate 111-1, respectively. The electrical connection between the third wiring 116-3 and the fifth wiring 116-5, and the electrical connection between the fourth wiring 116-4 and the sixth wiring 116-6, can be made, for example, using silver paste or conductive particles (including particles coated with metal).

[0066] Furthermore, in this embodiment, the first direction in which the first transparent electrode 112-1 and the second transparent electrode 112-2 are alternately arranged is orthogonal to the second direction in which the third transparent electrode 112-3 and the fourth transparent electrode 112-4 are alternately arranged, but they only need to intersect, and the intersection angle can be an angle other than 90 degrees. Additionally, by making the first transparent electrode 112-1 and the second transparent electrode 112-2 of the first substrate 111-1 intersect with the third transparent electrode 112-3 and the fourth transparent electrode 112-4 of the second substrate, as described later, the voltage applied to each transparent electrode can be controlled, thereby controlling the orientation of the liquid crystal in the liquid crystal layer 113. Thus, the orientation or light distribution pattern of light can be controlled.

[0067] Optical spacers (not shown) are formed on the first substrate 111-1 or the second substrate 111-2 to maintain their spacing.

[0068] The first wiring 116-1, second wiring 116-2, third wiring 116-3, fourth wiring 116-4, fifth wiring 116-5, and sixth wiring 116-6 can be made of metallic materials such as aluminum or molybdenum, or transparent conductive materials such as indium tin oxide (ITO) or indium zinc oxide (IZO). Furthermore, terminals for connecting to external devices can be provided on the first wiring 116-1, second wiring 116-2, fifth wiring 116-5, and sixth wiring 116-6.

[0069] The first wiring 116-1, the second wiring 116-2, the fifth wiring 116-5 (or the third wiring 116-3), and the sixth wiring 116-6 (or the fourth wiring 116-4) are electrically insulated from each other. Therefore, in the first liquid crystal cell 110, by applying different voltages to the first transparent electrode 112-1, the second transparent electrode 112-2, the third transparent electrode 112-3, and the fourth transparent electrode 112-4, the orientation of the liquid crystal molecules in the liquid crystal layer 113 can be controlled.

[0070] [3. Control of liquid crystal orientation]

[0071] Reference Figure 4A and Figure 4B The orientation of the liquid crystal in liquid crystal layer 113 is explained in detail.

[0072] Figure 4A and Figure 4B This is a cross-sectional schematic diagram showing the orientation of liquid crystal molecules in the liquid crystal layer 113 of an optical element 10 according to an embodiment of the present invention. Figure 4A and Figure 4B Corresponding to Figure 2A and Figure 2B A portion of the cross-sectional view of the first liquid crystal cell 110 shown.

[0073] like Figure 4A and Figure 4B As shown, the first substrate 111-1 and the second substrate 111-2 are bonded together with a substrate distance d. Furthermore, the first alignment film 114-1 of the first substrate 111-1 and the second alignment film 114-2 of the second substrate 111-2 are aligned along the x-axis and y-axis directions, respectively. Therefore, in the liquid crystal layer 113, when no voltage is applied to the transparent electrode, the long axis of the liquid crystal molecules on the first substrate 111-1 side is aligned along the x-axis direction (in...). Figure 4A and Figure 4B For convenience, arrows are used to indicate the orientation direction of liquid crystal molecules aligned along the left-right direction of the paper. That is, the orientation direction of the liquid crystal molecules on the first substrate 111-1 side is orthogonal to the extending directions of the first transparent electrode 112-1 and the second transparent electrode 112-2. Furthermore, without applying voltage to the transparent electrodes, the long axis of the liquid crystal molecules on the second substrate 111-2 side is aligned along the y-axis direction (in...). Figure 4A and Figure 4BFor convenience, a cross within a circle is used to indicate the orientation direction of liquid crystal molecules aligned along the normal direction of the paper. That is, the orientation direction of the liquid crystal molecules on the second substrate 111-2 side is orthogonal to the extending directions of the third transparent electrode 112-3 and the fourth transparent electrode 112-4. Therefore, the liquid crystal molecules of the liquid crystal layer 113 are aligned in the z-axis direction with a 90-degree twist as they move from the first substrate 111-1 toward the second substrate 111-2. More specifically, in Figure 4A In this configuration, the liquid crystal molecules on the first substrate 111-1 side are aligned along the alignment direction of the first alignment film 114-1 with their long axis oriented towards the x-axis (left-right direction on the paper). Meanwhile, the liquid crystal molecules on the second substrate 111-2 side are aligned along the alignment direction of the second alignment film 114-2 with their long axis oriented towards the y-axis (normal direction on the paper). Furthermore, the orientation of the long axis of the liquid crystal molecules located between them gradually changes from the x-axis to the y-axis as they move from the first substrate 111-1 towards the second substrate 111-2.

[0074] Next, refer to Figures 5A to 5C The orientation of the liquid crystal in the liquid crystal layer 113 when a voltage is applied is explained in detail.

[0075] Figure 5A This is a three-dimensional schematic diagram showing the orientation of liquid crystal molecules in the liquid crystal layer 113 when a voltage is applied in the optical element 10 according to one embodiment of the present invention. Additionally, Figure 5B and Figure 5C This is a cross-sectional schematic diagram showing the orientation of liquid crystal molecules in the liquid crystal layer 113 when a voltage is applied in the optical element 10 according to one embodiment of the present invention. Figure 5A For convenience, the first alignment film 114-1 and the second alignment film 114-2 are omitted in the text. Additionally, in... Figure 5B and Figure 5C In, with Figure 4A and Figure 4B Similarly, arrows or crosses marked in circles are used to illustrate the orientation directions of the first orientation film 114-1 and the second orientation film 114-2.

[0076] exist Figures 5A-5C In this process, a low potential is applied to the first transparent electrode 112-1 and the third transparent electrode 112-3, and a high potential is applied to the second transparent electrode 112-2 and the fourth transparent electrode 112-4 (in... Figures 5A-5CFor convenience, "-" and "+" symbols are used to illustrate low and high potentials, respectively. That is, a potential difference is generated between the first transparent electrode 112-1 and the second transparent electrode 112-2, and between the third transparent electrode 112-3 and the fourth transparent electrode 112-4. In this case, the liquid crystal molecules on the first substrate 111-1 side are aligned according to the electric field (potential distribution) generated between the first transparent electrode 112-1 and the second transparent electrode 112-2. That is, the long axis of the liquid crystal molecules on the first substrate 111-1 side is aligned along the direction from the first transparent electrode 112-1 toward the second transparent electrode 112-2. Similarly, the liquid crystal molecules on the second substrate 111-2 side are aligned along the direction from the third transparent electrode 112-3 toward the fourth transparent electrode 112-4. Furthermore, the electric field generated between adjacent transparent electrodes on the same substrate is sometimes referred to as the transverse electric field.

[0077] Furthermore, the orientation of the liquid crystal molecules will be explained in detail. The liquid crystal molecules on the first substrate 111-1 side are oriented along the x-axis in the absence of an electric field, but this orientation is the same as the direction of the lateral electric field between the first transparent electrode 112-1 and the second transparent electrode 112-2. Therefore, when viewed from above, the orientation of the liquid crystal molecules located approximately at the center between the first transparent electrode 112-1 and the second transparent electrode 112-2 is almost unaffected by this lateral electric field. Additionally, the liquid crystal molecules closer to the first transparent electrode 112-1 or the second transparent electrode 112-2 than the center are oriented tilted in the z-axis direction in response to the lateral electric field. Therefore, as... Figure 5B As shown, influenced by the lateral electric field between the first transparent electrode 112-1 and the second transparent electrode 112-2, the liquid crystal molecules on the first substrate 111-1 side are generally oriented in a convex arc shape between adjacent transparent electrodes, from the first transparent electrode 112-1 toward the second transparent electrode 112-2 when viewed from the first substrate 111-1. Similarly, the liquid crystal molecules on the second substrate 111-2 side are oriented along the y-axis, but the orientation of these liquid crystal molecules is the same as the orientation of the lateral electric field between the third transparent electrode 112-3 and the fourth transparent electrode 112-4. Therefore, the orientation of the liquid crystal molecules located approximately at the center between the third transparent electrode 112-3 and the fourth transparent electrode 112-4 hardly changes due to this lateral electric field. In addition, the liquid crystal molecules closer to the third transparent electrode 112-3 or the fourth transparent electrode 112-4 than the center are oriented at an angle in the z-axis direction. Therefore, as Figure 5CAs shown, influenced by the lateral electric field between the third transparent electrode 112-3 and the fourth transparent electrode 112-4, the liquid crystal molecules on the second substrate 111-2 side are generally aligned in a convex arc shape between each adjacent transparent electrode, from the third transparent electrode 112-3 toward the fourth transparent electrode 112-4 when viewed from the second substrate 111-2. Therefore, light incident on the liquid crystal layer 113 diffuses according to the refractive index distribution of the liquid crystal molecules aligned in a convex arc shape on the first substrate 111-1 side or the second substrate 111-2 side.

[0078] Since the first substrate 111-1 and the second substrate 111-2 have a sufficiently large inter-substrate distance d, the lateral electric field between the first transparent electrode 112-1 and the second transparent electrode 112-2 of the first substrate 111-1 will not affect the orientation of the liquid crystal molecules on the second substrate 111-2 side, or the effect is negligible. Similarly, the lateral electric field between the third transparent electrode 112-3 and the fourth transparent electrode 112-4 of the second substrate 111-2 will not affect the orientation of the liquid crystal molecules on the first substrate 111-1 side, or the effect is negligible.

[0079] Furthermore, in this specification, the liquid crystal layer 113 (or liquid crystal molecules) on the first substrate 111-1 side refers to the liquid crystal layer (or liquid crystal molecules) extending from the surface of the first substrate 111-1 to d / 2. Similarly, the liquid crystal layer 113 (or liquid crystal molecules) on the second substrate 111-2 side refers to the liquid crystal layer (or liquid crystal molecules) extending from the surface of the second substrate 111-2 to d / 2.

[0080] In the first liquid crystal cell 110, by controlling the voltage applied to the first transparent electrode 112-1, the second transparent electrode 112-2, the third transparent electrode 112-3, and the fourth transparent electrode, the orientation of the liquid crystal molecules in the liquid crystal layer 113 can be changed. The refractive index distribution of the liquid crystal layer 113 changes with the change in the orientation of the liquid crystal molecules. Therefore, the first liquid crystal cell 110 can diffuse transmitted light. The optical element 10 can utilize the change in the refractive index distribution of the liquid crystal layer 113 of the first liquid crystal cell 110 and the liquid crystal layer 123 of the second liquid crystal cell 120 to control the light distribution or light distribution pattern of the light transmitted through the optical element 10.

[0081] [5. Control of light distribution or light distribution pattern by optical elements]

[0082] Reference Figure 6A and Figure 6B The control of light distribution or light distribution pattern by optical element 10 is explained in detail.

[0083] Figure 6A and Figure 6BThis is a cross-sectional schematic diagram illustrating the control of light distribution by an optical element 10 according to one embodiment of the present invention. Figure 6A and Figure 6B The optical element 10 shown corresponds to Figure 2A A portion of the cross-sectional view of the first liquid crystal cell 110 and the second liquid crystal cell 120 shown. Figure 6A In the optical element 10 shown, no potential is applied to any transparent electrode. Additionally, in Figure 6B In the optical element 10 shown, a low potential is applied to the first transparent electrode 112-1 and the third transparent electrode 112-3 of the first liquid crystal cell 110, and a high potential is applied to the second transparent electrode 112-2 and the fourth transparent electrode 112-4. Similarly, a low potential is applied to the first transparent electrode 122-1 and the third transparent electrode 122-3 of the second liquid crystal cell 120, and a high potential is applied to the second transparent electrode 122-2 and the fourth transparent electrode 122-4. Furthermore, in Figure 6B For convenience, "-" and "+" symbols are used to illustrate low and high potentials, respectively.

[0084] exist Figure 6A and Figure 6B In the optical element 10 shown, the first alignment film 114-1 of the first liquid crystal cell 110 and the first alignment film 124-1 of the second liquid crystal cell 120 are aligned along the x-axis direction. On the other hand, the second alignment film 114-2 of the first liquid crystal cell 110 and the second alignment film 124-2 of the second liquid crystal cell 120 are aligned along the y-axis direction. Therefore, in the first liquid crystal cell 110, the alignment direction of the first alignment film 114-1 is the x-axis direction, and the alignment direction of the second alignment film 114-2 is the y-axis direction. Similarly, in the second liquid crystal cell 120, the alignment direction of the first alignment film 124-1 is the x-axis direction, and the alignment direction of the second alignment film 124-2 is the y-axis direction.

[0085] In the optical element 10 formed by stacking a first liquid crystal cell 110 and a second liquid crystal cell 120, when viewed from above, the first transparent electrode 112-1 of the first liquid crystal cell 110 and the first transparent electrode 122-1 of the second liquid crystal cell 120 overlap in a manner that is substantially consistent throughout the entire extending direction. The other transparent electrodes are similarly arranged. However, the first liquid crystal cell 110 and the second liquid crystal cell 120 can also be configured such that the first transparent electrodes 112-1 of the first liquid crystal cell 110 and the first transparent electrodes 122-1 of the second liquid crystal cell 120 overlap slightly offset in the x-axis direction or the y-axis direction. More specifically, when viewed from above, the first transparent electrodes 112-1 of the first liquid crystal cell 110 and the first transparent electrodes 122-1 of the second liquid crystal cell 120 partially or completely overlap each other throughout the entire extending direction. Alternatively, even if the first transparent electrodes 112-1 of the first liquid crystal cell 110 and the first transparent electrodes 122-1 of the second liquid crystal cell 120 do not overlap each other, it is sufficient as long as they extend in the same direction.

[0086] exist Figure 6A and Figure 6B In this process, light is incident from a direction perpendicular to the first substrate 111-1 of the first liquid crystal cell 110 and exits from the second substrate 121-2 of the second liquid crystal cell 120. The light incident on the first substrate 111-1 of the first liquid crystal cell 110 has x-axis polarization (P-polarization component) and y-axis polarization (S-polarization component). Therefore, for convenience, the x-axis polarization component of the light emitted from the light source will be designated as the first polarization component 310, and the y-axis polarization component as the second polarization component 320. These polarization components are transmitted through... Figure 6B The process of optical element 10 will be explained.

[0087] The first polarization component 310 and the second polarization component 320 correspond to the P-polarization component and S-polarization component of the light emitted from the light source, respectively (see reference). Figure 6B (1) in the middle. In addition, in Figure 6A and Figure 6B In the diagram, the P-polarization component is illustrated using an arrow (showing the arrow pointing horizontally to the paper), and the S-polarization component is illustrated using a cross marked on a circle (showing the arrow pointing in the direction of the normal to the paper).

[0088] The long axis of the liquid crystal molecules in the liquid crystal layer 113 on the first substrate 111-1 side of the first liquid crystal unit 110 is aligned along the x-axis direction, therefore, as Figure 6BAs shown, when a transverse electric field is generated between the first transparent electrode 112-1 and the second transparent electrode 112-2, the liquid crystal molecules have a refractive index distribution in the x-axis direction. Furthermore, the long axis of the liquid crystal molecules in the liquid crystal layer 113 on the second substrate 111-2 side of the first liquid crystal unit 110 is aligned along the y-axis direction. Therefore, when a transverse electric field is generated between the third transparent electrode 112-3 and the fourth transparent electrode 112-4, the liquid crystal molecules have a refractive index distribution in the y-axis direction.

[0089] Therefore, the first polarization component 310 incident on the optical element 10 (more specifically, the first liquid crystal cell 110), after being incident on the first substrate 111-1, changes to an S-polarization component as the liquid crystal orientation twists with the orientation toward the second substrate 111-2 (refer to...). Figure 6B (2) to (4)). More specifically, the first polarizing component 310 has a polarization axis along the x-axis direction on the first substrate 111-1 side, but its polarization axis gradually changes as it passes through the thickness direction of the liquid crystal layer 113, and becomes a polarization axis along the y-axis direction on the second substrate 111-2 side, and then is emitted from the second substrate 111-2 side (see reference). Figure 6B (5) in the middle. Here, as Figure 6B As shown, when a transverse electric field is generated between the first transparent electrode 112-1 and the second transparent electrode 112-2, the orientation state of the liquid crystal molecules is affected by this transverse electric field as follows: Figure 5A The refractive index distribution changes as shown. Furthermore, on the first substrate 111-1 side, the polarization axis of the first polarization component 310 is parallel to the orientation direction of the liquid crystal molecules in the liquid crystal layer 113 on the first substrate 111-1 side. Therefore, the first polarization component 310 diffuses along the x-axis direction according to the change in the refractive index distribution of the liquid crystal molecules. Additionally, by changing the polarization axis of the first polarization component 310 from the x-axis direction to the y-axis direction within the liquid crystal layer 113, on the second substrate 111-2 side, its polarization axis becomes parallel to the orientation direction of the liquid crystal molecules in the liquid crystal layer 113 on the second substrate 111-2 side. Here, as... Figure 6B As shown, when a transverse electric field is generated between the third transparent electrode 112-3 and the fourth transparent electrode 112-4, the orientation state of the liquid crystal molecules is affected by this transverse electric field as follows: Figure 5B The refractive index distribution changes as shown. Therefore, the first polarization component 310 diffuses along the y-axis according to the change in the refractive index distribution of the liquid crystal molecules.

[0090] In addition, such as Figure 6BAs shown, the second polarization component 320, which was S-polarized before incident on the optical element 10 (more specifically, the first liquid crystal cell 110), changes to P-polarized as the liquid crystal orientation twists after incident on the first substrate 111-1 and toward the second substrate 111-2 (see reference). Figure 6B (2) to (4)). More specifically, the second polarization component 320 has a polarization axis along the y-axis direction on the first substrate 111-1 side, but its polarization axis gradually changes as it passes through the thickness direction of the liquid crystal layer 113, and becomes a polarization axis along the x-axis direction on the second substrate 111-2 side, and then is emitted from the second substrate 111-2 side (refer to...). Figure 6B (5)). Here, even if a transverse electric field is generated between the first transparent electrode 112-1 and the second transparent electrode 112-2, since the polarization axis of the second polarization component 320 is orthogonal to the orientation direction of the liquid crystal molecules in the liquid crystal layer 113 on the first substrate 111-1 side, it passes directly without diffusion, unaffected by the refractive index distribution of the liquid crystal molecules. In addition, by changing the polarization axis of the second polarization component 320 from the y-axis direction to the x-axis direction within the liquid crystal layer 113, its polarization axis is also orthogonal to the orientation direction of the liquid crystal molecules on the second substrate 111-2 side. Therefore, it passes directly without diffusion, unaffected by the refractive index distribution of the liquid crystal molecules.

[0091] That is, the second polarization component 320, which is S-polarized before it is incident on the optical element 10, changes its polarization axis from the y-axis direction to the x-axis direction and becomes P-polarized as it passes through the first liquid crystal cell 110, but does not produce the diffusion of the first polarization component 310.

[0092] The liquid crystal molecules of the liquid crystal layer 123 of the second liquid crystal cell 120 also have the same refractive index distribution as the liquid crystal molecules of the liquid crystal layer 113 of the first liquid crystal cell 110. Therefore, the same phenomenon as in the first liquid crystal cell 110 is generated in the second liquid crystal cell 120. On the other hand, the polarization axes of the first polarization component 310 and the second polarization component 320 are reversed by passing through the first liquid crystal cell 110, and therefore, the polarization component affected by the refractive index distribution of the liquid crystal molecules in the liquid crystal layer 113 is also reversed. That is, as Figure 6B As shown, even though a transverse electric field is generated between the first transparent electrode 122-1 and the second transparent electrode 122-2, and between the third transparent electrode 122-3 and the fourth transparent electrode 112-4 of the second liquid crystal cell 120, although the polarization axis of the first polarization component 310 passing through the second liquid crystal cell 120 changes again from the y-axis direction to the x-axis direction (refer to...) Figure 6B(6) to (8) in the middle, but no diffusion occurs. On the other hand, the polarization axis of the second polarization component 320 passing through the second liquid crystal cell 120 changes again from the x-axis direction to the y-axis direction (see reference). Figure 6B (6) to (8) in the liquid crystal layer 123 diffuses due to the influence of the refractive index distribution of the liquid crystal molecules.

[0093] As can be seen from the above, in optical element 10, by stacking two liquid crystal cells with the same structure, the polarization direction of the light incident on optical element 10 is changed twice. As a result, the polarization direction before and after incident remains unchanged (refer to...). Figure 6B (1) and (9) in the text). On the other hand, the optical element 10 can change the refractive index distribution of the liquid crystal molecules in the liquid crystal layer of the liquid crystal cell, causing the transmitted light to refract. More specifically, the first liquid crystal cell 110 diffuses the light of the first polarization component 310 (P-polarization component) in the x-axis direction, the y-axis direction, or both the x-axis and the y-axis directions, and the second liquid crystal cell 120 diffuses the light of the second polarization component 320 (S-polarization component) in the x-axis direction, the y-axis direction, or both the x-axis and the y-axis directions. Therefore, the optical element 10 can diffuse unpolarized light without changing the polarization state of the light.

[0094] In addition, the above are the main uses Figure 6B The process of diffusion and polarization axis change as each polarization component passes through the optical element 10 is explained. Figure 6A The optical element 10, except that it is in a state where no potential is applied to each transparent electrode (there is no potential difference between adjacent transparent electrodes) and does not cause the polarization component to diffuse, is similar to... Figure 6B Similarly, optical elements cause a change in the polarization axis of the polarization component. To avoid repetition, [the following is an explanation of the optical elements used in this context:] through... Figure 6A The description and labeling of the polarization components of the optical elements Figure 6B The same reference numerals are used for (1) to (9) and their descriptions are omitted.

[0095] In addition, such as Figure 6A and Figure 6BAs shown, an optical elastic resin layer 130 is disposed between the first liquid crystal cell 110 and the second liquid crystal cell 120. Light can be refracted at the interface between the second substrate 111-2 of the first liquid crystal cell 110 and the optical elastic resin layer 130, or at the interface between the first substrate 121-1 of the second liquid crystal cell 120 and the optical elastic resin layer 130. Therefore, it is preferable that the refractive index of the optical elastic resin of the optical elastic resin layer 130 is close to the refractive index of the second substrate 111-2 of the first liquid crystal cell 110 and the first substrate 121-1 of the second liquid crystal cell 120. In addition, since the optical element 10 is disposed near the light source, its temperature may rise due to heat from the light source. In this case, it is preferable that the thickness of the optical elastic resin layer 130 is greater than the inter-substrate distance d between the first substrate 111-1 and the second substrate 111-2 in the first liquid crystal cell 110 or between the first substrate 121-1 and the second substrate 121-2 in the second liquid crystal cell 120, so as to mitigate the effect of thermal expansion of the optical elastic resin of the optical elastic resin layer 130.

[0096] The optical element 10 not only diffuses light, but also controls the light distribution by applying potentials to each transparent electrode, thus forming a predetermined light distribution pattern. Hereinafter, refer to... Figures 7A to 10 Examples of light distribution patterns controlled by optical element 10 are shown. However, the light distribution patterns controlled by optical element 10 are not limited to these. Furthermore, Figures 7A to 10 The symbol for the potential recorded in the document (V) 11 (etc.) are shown in Table 1.

[0097] [Table 1]

[0098]

[0099] For convenience, the potentials applied to each transparent electrode will be described below as follows: a first potential (variable potential, e.g., a low potential of 0V and a high potential of 30V), a second potential (variable potential, e.g., a low potential of 0V and a high potential of 30V) with the opposite phase to the first potential, and a third potential (intermediate potential, e.g., 15V). The third potential is the potential between the low and high potentials, and can be either a fixed potential or a variable potential. Furthermore, the voltage value is not limited to... Figures 7A to 10 The recorded values ​​are 0V, 15V, and 30V.

[0100] [Example 1: Light distribution pattern extending along the x-axis]

[0101] Figure 7A This is a timing diagram showing the potentials applied to each transparent electrode included in an optical element 10 according to one embodiment of the present invention. Additionally, Figure 7B In one embodiment of the present invention, the transparent electrodes are applied to the optical element 10. Figure 7A A photograph of the light distribution pattern obtained by adjusting the potential shown.

[0102] In the first liquid crystal cell 110, a first potential and a second potential are applied to the first transparent electrode 112-1 and the second transparent electrode 112-2, respectively. Furthermore, a third potential is applied to the third transparent electrode 112-3 and the fourth transparent electrode 112-4, respectively. The phase of the first potential applied to the first transparent electrode 112-1 is opposite to the phase of the second potential applied to the second transparent electrode 112-2. Therefore, a potential difference (e.g., +30V or -30V) is generated between the first transparent electrode 112-1 and the second transparent electrode 112-2. In contrast, there is no potential between the third transparent electrode 112-3 and the fourth transparent electrode 112-4 on the second substrate 111-2 side. In addition, the third transparent electrode 112-3 and the fourth transparent electrode 112-4 on the second substrate 111-2 side generate +15V or -15V with the first transparent electrode 112-1 on the first substrate 111-1 side or with the second transparent electrode 112-2 in any state. In absolute terms, there is no deviation in the potential difference between the first transparent electrode on the first substrate 111-1 side and the other transparent electrode.

[0103] Therefore, the liquid crystal molecules on the first substrate 111-1 side change their orientation state according to the potential difference between the first transparent electrode 112-1 and the second transparent electrode 112-2 (see reference). Figures 5A-5C (etc.). On the other hand, since no potential difference is generated between the third transparent electrode 112-3 and the fourth transparent electrode 112-4, and the first substrate 111-1 and the second substrate 111-2 are sufficiently separated to the extent that they are not affected by the potential on the first substrate 111-1 side, the liquid crystal molecules on the second substrate 111-2 side will not change their orientation direction from the initial orientation direction. In addition, since the third potential applied to the third transparent electrode 112-3 and the fourth transparent electrode 112-4 is an intermediate potential between the first potential and the second potential, even if low and high potentials are alternately applied to the first transparent electrode 112-1 and the second transparent electrode 112-2, no capacitance will accumulate, and the orientation state of the liquid crystal molecules on the second substrate 111-2 side will not change.

[0104] In the second liquid crystal cell 120, a first potential and a second potential are applied to the first transparent electrode 122-1 and the second transparent electrode 122-2, respectively. Furthermore, a third potential is applied to the third transparent electrode 122-3 and the fourth transparent electrode 122-4, respectively. The phase of the first potential applied to the first transparent electrode 122-1 is opposite to the phase of the second potential applied to the second transparent electrode 122-2. Therefore, a potential difference (e.g., +30V or -30V) is generated between the first transparent electrode 122-1 and the second transparent electrode 122-2. In contrast, there is no potential between the third transparent electrode 122-3 and the fourth transparent electrode 122-4 on the second substrate 121-2 side. In addition, the third transparent electrode 122-3 and the fourth transparent electrode 122-4 on the second substrate 121-2 side generate +15V or -15V with the first transparent electrode 122-1 on the first substrate 121-1 side or with the second transparent electrode 122-2 in any state. In absolute terms, there is no deviation in the potential difference between the transparent electrode on the first substrate 121-1 side and the other transparent electrode.

[0105] Therefore, the liquid crystal molecules on the first substrate 121-1 side change their orientation state according to the potential difference between the first transparent electrode 122-1 and the second transparent electrode 122-2 (see reference). Figures 5A-5C (etc.). On the other hand, since no potential difference is generated between the third transparent electrode 122-3 and the fourth transparent electrode 122-4, and the first substrate 121-1 and the second substrate 121-2 are sufficiently separated to the extent that they are not affected by the potential on the first substrate 121-1 side, the liquid crystal molecules on the second substrate 121-2 side will not change their orientation direction from the initial orientation direction. In addition, since the third potential applied to the third transparent electrode 122-3 and the fourth transparent electrode 122-4 is an intermediate potential between the first potential and the second potential, even if low and high potentials are alternately applied to the first transparent electrode 122-1 and the second transparent electrode 122-2, no capacitance will accumulate, and the orientation state of the liquid crystal molecules on the second substrate 121-2 side will not change.

[0106] In addition, such as Figure 7A As shown, the potential changes of the first transparent electrode 112-1 and the second transparent electrode 112-2 of the first liquid crystal cell 110 are synchronized with the potential changes of the first transparent electrode 122-1 and the second transparent electrode 122-2 of the second liquid crystal cell 120.

[0107] When the aforementioned potential is applied to each transparent electrode, the liquid crystal molecules of the liquid crystal layer 113 on the first substrate 111-1 side of the first liquid crystal cell 110 can refract light polarized in the x-axis direction. Therefore, the first liquid crystal cell 110 can diffuse light polarized in the x-axis direction.

[0108] Furthermore, the liquid crystal molecules in the liquid crystal layer 123 on the first substrate 121-1 side of the second liquid crystal cell 120 also refract light polarized in the x-axis direction in the x-axis direction. Therefore, the second liquid crystal cell 120 also diffuses light polarized in the x-axis direction along the x-axis direction.

[0109] That is, the potential of each transparent electrode is Figure 7A When the potential shown is reached, if light is incident from the first substrate 111-1 side of the first liquid crystal cell 110 (e.g.) Figure 6A and Figure 6B As shown, this means that light is irradiated from below the first liquid crystal cell 110 toward the first substrate 111-1. (The same applies below.) Then, as the optical element 10 passes through the first liquid crystal cell 110, the first polarization component 310, having a polarization axis in the x-axis direction, diffuses along the x-axis direction on the side of the first substrate 111-1, and changes the polarization axis in the y-axis direction. On the other hand, the second polarization component 320, having a polarization in the y-axis direction, does not diffuse, causing the polarization axis to change from the y-axis direction to the x-axis direction. Furthermore, these polarization components are directly incident on the second liquid crystal cell 120. The second polarization component 320, which does not diffuse within the first liquid crystal cell 110 and changes the polarization axis from the y-axis direction to the x-axis direction, diffuses along the x-axis direction as it passes through the second liquid crystal cell 120, and then changes the polarization axis in the y-axis direction. On the other hand, the first polarization component 310, which diffuses within the first liquid crystal cell 110 and changes the polarization axis from the x-axis direction to the y-axis direction, does not diffuse, and changes the polarization axis from the y-axis direction to the x-axis direction. Therefore, light incident on the optical element 10 diffuses along the x-axis as it passes through the first liquid crystal cell 110 or the second liquid crystal cell 120. Thus, as... Figure 7B As shown, light passing through optical element 10 can form a light distribution pattern A that extends along the x-axis.

[0110] [Example 2: Light distribution pattern extending along the y-axis]

[0111] Figure 8A This is a timing diagram showing the voltages applied to each transparent electrode included in an optical element 10 according to one embodiment of the present invention. Additionally, Figure 8B In one embodiment of the present invention, the transparent electrodes are applied to the optical element 10. Figure 8A A photograph of the light distribution pattern obtained by adjusting the potential shown.

[0112] In the first liquid crystal cell 110, a third potential is applied to the first transparent electrode 112-1 and the second transparent electrode 112-2, respectively. Additionally, a first potential and a second potential are applied to the third transparent electrode 112-3 and the fourth transparent electrode 112-4, respectively. The phase of the first potential applied to the third transparent electrode 112-3 is opposite to the phase of the second potential applied to the fourth transparent electrode 112-4. Therefore, a potential difference (e.g., +30V or -30V) is generated between the third transparent electrode 112-3 and the fourth transparent electrode 112-4. In contrast, there is no potential between the first transparent electrode 112-1 and the second transparent electrode 112-2 on the first substrate 111-1 side. In addition, the first transparent electrode 112-1 and the second transparent electrode 112-2 on the first substrate 111-1 side generate +15V or -15V between themselves and the third transparent electrode 112-3 or the fourth transparent electrode 112-4 on the second substrate 111-2 side in any state. In absolute terms, there is no deviation in the potential difference between themselves and one transparent electrode on the second substrate 111-2 side or between themselves and the other transparent electrode.

[0113] Therefore, the liquid crystal molecules on the second substrate 111-2 side change their orientation state according to the potential difference between the third transparent electrode 112-3 and the fourth transparent electrode 112-4 (see reference). Figures 5A-5C (etc.). On the other hand, since no potential difference is generated between the first transparent electrode 112-1 and the second transparent electrode 112-2, and the first substrate 111-1 and the second substrate 111-2 are sufficiently separated to be unaffected by the potential on the second substrate 111-2 side, the liquid crystal molecules on the first substrate 111-1 side will not change their orientation direction from the initial orientation direction. In addition, since the third potential applied to the first transparent electrode 112-1 and the second transparent electrode 112-2 is an intermediate potential between the first potential and the second potential, even if low and high potentials are alternately applied to the third transparent electrode 112-3 and the fourth transparent electrode 112-4, no capacitance will accumulate, and the orientation state of the liquid crystal molecules on the first substrate 111-1 side will not change.

[0114] In the second liquid crystal cell 120, a third potential is applied to the first transparent electrode 122-1 and the second transparent electrode 122-2, respectively. Additionally, a first potential and a second potential are applied to the third transparent electrode 122-3 and the fourth transparent electrode 122-4, respectively. The phase of the first potential applied to the third transparent electrode 122-3 is opposite to the phase of the second potential applied to the fourth transparent electrode 122-4. Therefore, a potential difference (e.g., +30V or -30V) is generated between the third transparent electrode 122-3 and the fourth transparent electrode 122-4. In contrast, there is no potential between the first transparent electrode 122-1 and the second transparent electrode 122-2 on the first substrate 121-1 side. In addition, the first transparent electrode 122-1 and the second transparent electrode 122-2 on the first substrate 121-1 side generate +15V or -15V between themselves and the third transparent electrode 122-3 or the fourth transparent electrode 122-4 on the second substrate 121-2 side in any state. In absolute terms, there is no deviation in the potential difference between themselves and one transparent electrode on the second substrate 121-2 side and between themselves and the other transparent electrode.

[0115] Therefore, the liquid crystal molecules on the second substrate 121-2 side change their orientation state according to the potential difference between the third transparent electrode 122-3 and the fourth transparent electrode 122-4 (see reference). Figures 5A-5C (etc.). On the other hand, since no potential difference is generated between the first transparent electrode 122-1 and the second transparent electrode 122-2, and the first substrate 121-1 and the second substrate 121-2 are sufficiently separated to be unaffected by the potential on the second substrate 121-2 side, the liquid crystal molecules on the first substrate 121-1 side will not change their orientation direction from the initial orientation direction. In addition, since the third potential applied to the first transparent electrode 122-1 and the second transparent electrode 122-2 is an intermediate potential between the first potential and the second potential, even if low and high potentials are alternately applied to the third transparent electrode 122-3 and the fourth transparent electrode 122-4, no capacitance will accumulate, and the orientation state of the liquid crystal molecules on the first substrate 121-1 side will not change.

[0116] In addition, such as Figure 8B As shown, the potential changes of the third transparent electrode 112-3 and the fourth transparent electrode 112-4 of the first liquid crystal cell 110 are synchronized with the potential changes of the third transparent electrode 122-3 and the fourth transparent electrode 122-4 of the second liquid crystal cell 120, respectively.

[0117] When the aforementioned potential is applied to each transparent electrode, the liquid crystal molecules of the liquid crystal layer 113 on the second substrate 111-2 side of the first liquid crystal cell 110 can refract light polarized in the y-axis direction in the y-axis direction. Therefore, the first liquid crystal cell 110 also diffuses light polarized in the y-axis direction along the y-axis direction.

[0118] Furthermore, the liquid crystal molecules in the liquid crystal layer 123 on the second substrate 121-2 side of the second liquid crystal cell 120 also refract light polarized in the y-axis direction in the y-axis direction. Therefore, the second liquid crystal cell 120 also diffuses light polarized in the y-axis direction along the y-axis direction.

[0119] That is, the potential of each transparent electrode is Figure 8A When light is incident from the first substrate 111-1 side of the first liquid crystal cell 110 at the indicated potential, the optical element 10 causes the polarization axis of the first polarization component 310, which has polarization in the x-axis direction, to change from the x-axis direction to the y-axis direction as it passes through the first liquid crystal cell 110, and diffuses along the y-axis direction on the second substrate 111-2 side. On the other hand, the second polarization component 320, which has polarization in the y-axis direction, does not diffuse, and its polarization axis changes from the y-axis direction to the x-axis direction. Moreover, these polarization components are directly incident on the second liquid crystal cell 120. The second polarization component 320, which does not diffuse within the first liquid crystal cell 110 and whose polarization axis changes from the y-axis direction to the x-axis direction, changes its polarization axis to the y-axis direction as it passes through the second liquid crystal cell 120, and diffuses along the y-axis direction on the second substrate 121-2 side. On the other hand, the first polarization component 310, which diffuses within the first liquid crystal cell 110 and whose polarization axis changes from the x-axis direction to the y-axis direction, does not diffuse, and its polarization axis changes from the y-axis direction to the x-axis direction. Therefore, light incident on the optical element 10 diffuses along the y-axis as it passes through the first liquid crystal cell 110 or the second liquid crystal cell 120. Thus, as... Figure 8B As shown, light passing through optical element 10 can form a light distribution pattern B that extends along the y-axis.

[0120] [Example 3: A cross-shaped light distribution pattern]

[0121] Figure 9A This is a timing diagram showing the potentials applied to each transparent electrode included in an optical element 10 according to one embodiment of the present invention. Additionally, Figure 9B In one embodiment of the present invention, the transparent electrodes are applied to the optical element 10. Figure 9A A photograph of the light distribution pattern obtained by adjusting the potential shown.

[0122] In the first liquid crystal cell 110, a first potential and a second potential are applied to the first transparent electrode 112-1 and the second transparent electrode 112-2, respectively. Furthermore, a third potential is applied to the third transparent electrode 112-3 and the fourth transparent electrode 112-4, respectively. The phase of the first potential applied to the first transparent electrode 112-1 is opposite to the phase of the second potential applied to the second transparent electrode 112-2. Therefore, a potential difference (e.g., +30V or -30V) is generated between the first transparent electrode 112-1 and the second transparent electrode 112-2. In contrast, there is no potential between the third transparent electrode 112-3 and the fourth transparent electrode 112-4 on the second substrate 111-2 side. In addition, the third transparent electrode 112-3 and the fourth transparent electrode 112-4 on the second substrate 111-2 side generate +15V or -15V with the first transparent electrode 112-1 on the first substrate 111-1 side or with the second transparent electrode 112-2 in any state. In absolute terms, there is no deviation in the potential difference between the first transparent electrode on the first substrate 111-1 side and the other transparent electrode.

[0123] Therefore, the liquid crystal molecules on the first substrate 111-1 side change their orientation state according to the potential difference between the first transparent electrode 112-1 and the second transparent electrode 112-2 (see reference). Figures 5A-5C (etc.). On the other hand, since no potential difference is generated between the third transparent electrode 112-3 and the fourth transparent electrode 112-4, and the first substrate 111-1 and the second substrate 111-2 are sufficiently separated to the extent that they are not affected by the potential on the first substrate 111-1 side, the liquid crystal molecules on the second substrate 111-2 side will not change their orientation direction from the initial orientation direction. In addition, since the third potential applied to the third transparent electrode 112-3 and the fourth transparent electrode 112-4 is an intermediate potential between the first potential and the second potential, even if low and high potentials are alternately applied to the first transparent electrode 112-1 and the second transparent electrode 112-2, no capacitance will accumulate, and the orientation state of the liquid crystal molecules on the second substrate 111-2 side will not change.

[0124] In the second liquid crystal cell 120, a third potential is applied to the first transparent electrode 122-1 and the second transparent electrode 122-2, respectively. Additionally, a first potential and a second potential are applied to the third transparent electrode 122-3 and the fourth transparent electrode 122-4, respectively. The phase of the first potential applied to the third transparent electrode 122-3 is opposite to the phase of the second potential applied to the fourth transparent electrode 122-4. Therefore, a potential difference (e.g., +30V or -30V) is generated between the third transparent electrode 122-3 and the fourth transparent electrode 122-4. In contrast, there is no potential between the first transparent electrode 122-1 and the second transparent electrode 122-2 on the first substrate 121-1 side. In addition, the first transparent electrode 122-1 and the second transparent electrode 122-2 on the first substrate 121-1 side generate +15V or -15V between themselves and the third transparent electrode 122-3 or the fourth transparent electrode 122-4 on the second substrate 121-2 side in any state. In absolute terms, there is no deviation in the potential difference between themselves and one transparent electrode on the second substrate 121-2 side and between themselves and the other transparent electrode.

[0125] Therefore, the liquid crystal molecules on the second substrate 121-2 side change their orientation state according to the potential difference between the third transparent electrode 122-3 and the fourth transparent electrode 122-4 (see reference). Figures 5A-5C (etc.). On the other hand, since no potential difference is generated between the first transparent electrode 122-1 and the second transparent electrode 122-2, and the first substrate 121-1 and the second substrate 121-2 are sufficiently separated to be unaffected by the potential on the second substrate 121-2 side, the liquid crystal molecules on the first substrate 121-1 side will not change their orientation direction from the initial orientation direction. In addition, since the third potential applied to the first transparent electrode 122-1 and the second transparent electrode 122-2 is an intermediate potential between the first potential and the second potential, even if low and high potentials are alternately applied to the third transparent electrode 122-3 and the fourth transparent electrode 122-4, no capacitance will accumulate, and the orientation state of the liquid crystal molecules on the first substrate 121-1 side will not change.

[0126] In addition, such as Figure 9A As shown, the potential changes of the first transparent electrode 112-1 and the second transparent electrode 112-2 of the first liquid crystal cell 110 are synchronized with the potential changes of the third transparent electrode 122-3 and the fourth transparent electrode 122-4 of the second liquid crystal cell 120, respectively.

[0127] When the aforementioned potential is applied to each transparent electrode, the liquid crystal molecules of the liquid crystal layer 113 on the first substrate 111-1 side of the first liquid crystal cell 110 refract light polarized in the x-axis direction. Therefore, the first liquid crystal cell 110 diffuses light polarized in the x-axis direction.

[0128] Furthermore, the liquid crystal molecules in the liquid crystal layer 123 on the second substrate 121-2 side of the second liquid crystal cell 120 refract light polarized in the y-axis direction in the y-axis direction. Therefore, the second liquid crystal cell 120 diffuses light polarized in the y-axis direction along the y-axis direction.

[0129] That is, the potential of each transparent electrode is Figure 9A When light is incident from the first substrate 111-1 side of the first liquid crystal cell 110 at the indicated potential, the optical element 10 causes the first polarization component 310, which has polarization in the x-axis direction, to diffuse along the x-axis direction on the first substrate 111-1 side as it passes through the first liquid crystal cell 110, and causes the polarization axis to change from the x-axis direction to the y-axis direction. On the other hand, the second polarization component 320, which has polarization in the y-axis direction, does not diffuse, and causes the polarization axis to change from the y-axis direction to the x-axis direction. Moreover, these polarization components are directly incident on the second liquid crystal cell 120. The second polarization component 320, which does not diffuse within the first liquid crystal cell 110 and causes the polarization axis to change from the y-axis direction to the x-axis direction, causes the polarization axis to change from the x-axis direction to the y-axis direction as it passes through the second liquid crystal cell 120, and diffuses along the y-axis direction on the second substrate 121-2 side. On the other hand, the first polarization component 310, which diffuses within the first liquid crystal cell 110 and causes the polarization axis to change from the x-axis direction to the y-axis direction, does not diffuse, and causes the polarization axis to change from the y-axis direction to the x-axis direction. Thus, the light incident on the optical element 10 diffuses along the x-axis as the first polarization component 310 passes through the first liquid crystal cell 110, and diffuses along the y-axis as the second polarization component 320 passes through the second liquid crystal cell 120. Therefore, as... Figure 9B As shown, light passing through optical element 10 can form a cross-shaped light distribution pattern C.

[0130] Furthermore, as described above, by applying to each transparent electrode Figure 9A The potential shown primarily forms a cross-shaped light distribution pattern by diffusing the first polarizing component 310. However, by changing the potential supplied to each transparent electrode, the second polarizing component 320 can be diffused to form a cross-shaped light distribution pattern. Specifically, in the first liquid crystal cell 110, a first potential and a second potential are applied to the third transparent electrode 112-3 and the fourth transparent electrode 112-4, respectively, and a third potential is applied to the first transparent electrode 112-1 and the second transparent electrode 112-2, respectively. Furthermore, in the second liquid crystal cell 120, a first potential and a second potential are applied to the first transparent electrode 122-1 and the second transparent electrode 122-2, respectively, and a third potential is applied to the third transparent electrode 122-3 and the fourth transparent electrode 122-4, respectively. Thus, a cross-shaped light distribution pattern is formed primarily by diffusing the second polarizing component 320.

[0131] [Example 4: A light distribution pattern that extends in a rectangular shape]

[0132] Figure 10 This is a timing diagram showing the voltage applied to each transparent electrode included in an optical element 10 according to one embodiment of the present invention.

[0133] In the first liquid crystal cell 110, a first potential is applied to the first transparent electrode 112-1 and the third transparent electrode 112-3, respectively. A second potential is applied to the second transparent electrode 112-2 and the fourth transparent electrode 112-4, respectively. The phase of the first potential applied to the first transparent electrode 112-1 and the third transparent electrode 112-3 is opposite to the phase of the second potential applied to the second transparent electrode 112-2 and the fourth transparent electrode 112-4. Therefore, a potential difference (e.g., +30V or -30V) is generated between the first transparent electrode 112-1 and the second transparent electrode 112-2, and between the third transparent electrode 112-3 and the fourth transparent electrode 112-4. Additionally, a potential difference (e.g., +30V or -30V) is also generated between the first transparent electrode 112-1 and the fourth transparent electrode 112-4, and between the second transparent electrode 112-2 and the third transparent electrode 112-3.

[0134] Therefore, the liquid crystal molecules on the first substrate 111-1 side change their orientation state according to the potential difference between the first transparent electrode 112-1 and the second transparent electrode 112-2 (see reference). Figures 5A-5C (etc.). Furthermore, the liquid crystal molecules on the second substrate 111-2 side change their orientation state according to the potential difference between the third transparent electrode 112-3 and the fourth transparent electrode 112-4 (see reference). Figures 5A to 5C (etc.). Furthermore, since the first substrate 111-1 and the second substrate 111-2 are sufficiently separated, the first potential applied to the third transparent electrode 112-3 or the second potential applied to the fourth transparent electrode 112-4 has little effect on the liquid crystal molecules on the first substrate 111-1 side. Similarly, the first potential applied to the first transparent electrode 112-1 or the second potential applied to the second transparent electrode 112-2 has little effect on the liquid crystal molecules on the second substrate 111-2 side.

[0135] In the second liquid crystal cell 120, a first potential is applied to the first transparent electrode 122-1 and the third transparent electrode 122-3, respectively. A second potential is applied to the second transparent electrode 122-2 and the fourth transparent electrode 122-4, respectively. The phase of the first potential applied to the first transparent electrode 122-1 and the third transparent electrode 122-3 is opposite to the phase of the second potential applied to the second transparent electrode 122-2 and the fourth transparent electrode 122-4. Therefore, a potential difference (e.g., +30V or -30V) is generated between the first transparent electrode 122-1 and the second transparent electrode 122-2, and between the third transparent electrode 122-3 and the fourth transparent electrode 122-4. Additionally, a potential difference (e.g., +30V or -30V) is also generated between the first transparent electrode 122-1 and the fourth transparent electrode 122-4, and between the second transparent electrode 122-2 and the third transparent electrode 122-3.

[0136] Therefore, the liquid crystal molecules on the first substrate 121-1 side change their orientation state according to the potential difference between the first transparent electrode 122-1 and the second transparent electrode 122-2 (see reference). Figures 5A-5C (etc.). Furthermore, the liquid crystal molecules on the second substrate 121-2 side change their orientation state according to the potential difference between the third transparent electrode 122-3 and the fourth transparent electrode 122-4 (see reference). Figures 5A-5C (etc.). Furthermore, since the first substrate 121-1 and the second substrate 121-2 are sufficiently separated, the first potential applied to the third transparent electrode 122-3 or the second potential applied to the fourth transparent electrode 122-4 has little effect on the liquid crystal molecules on the first substrate 121-1 side. Similarly, the first potential applied to the first transparent electrode 122-1 or the second potential applied to the second transparent electrode 122-2 has little effect on the liquid crystal molecules on the second substrate 121-2 side.

[0137] In addition, such as Figure 10 As shown, the potential changes of the first transparent electrode 112-1 and the third transparent electrode 112-3 of the first liquid crystal cell 110 and the first transparent electrode 122-1 and the third transparent electrode 122-3 of the second liquid crystal cell 120 are synchronized with each other. Furthermore, the potential changes of the second transparent electrode 112-2 and the fourth transparent electrode 112-4 of the first liquid crystal cell 110 and the second transparent electrode 122-2 and the fourth transparent electrode 122-4 of the second liquid crystal cell 120 are synchronized with each other.

[0138] When the aforementioned potential is applied to each transparent electrode, the liquid crystal molecules of the liquid crystal layer 113 on the first substrate 111-1 side of the first liquid crystal cell 110 refract light polarized in the x-axis direction in the x-axis direction. Furthermore, the liquid crystal molecules of the liquid crystal layer 113 on the second substrate 111-2 side of the first liquid crystal cell 110 refract light polarized in the y-axis direction in the y-axis direction. Therefore, the first liquid crystal cell 110 diffuses light polarized in the x-axis direction along both the x-axis and y-axis directions.

[0139] Furthermore, the liquid crystal molecules in the liquid crystal layer 123 on the first substrate 121-1 side of the second liquid crystal cell 120 refract light polarized in the x-axis direction in the x-axis direction. Additionally, the liquid crystal molecules in the liquid crystal layer 123 on the second substrate 121-2 side of the second liquid crystal cell 120 refract light polarized in the y-axis direction in the y-axis direction. Therefore, the second liquid crystal cell 120 also diffuses light polarized in the x-axis direction along both the x-axis and y-axis directions.

[0140] That is, the potential of each transparent electrode is Figure 10 When light is incident from the first substrate 111-1 side of the first liquid crystal cell 110 at the indicated potential, the optical element 10 causes the first polarization component 310, which has polarization in the x-axis direction, to diffuse along the x-axis direction on the first substrate 111-1 side as it passes through the first liquid crystal cell 110, and causes the polarization axis to change from the x-axis direction to the y-axis direction. Additionally, the first polarization component 310, which causes the polarization axis to change from the x-axis direction to the y-axis direction, diffuses along the y-axis direction on the second substrate 111-2 side. On the other hand, the second polarization component 320, which has polarization in the y-axis direction, does not diffuse, causing the polarization axis to change from the y-axis direction to the x-axis direction. Furthermore, these polarization components are directly incident on the second liquid crystal cell 120. The second polarization component 320, which does not diffuse within the first liquid crystal cell 110 and causes the polarization axis to change from the y-axis direction to the x-axis direction, diffuses along the x-axis direction on the first substrate 121-1 side as it passes through the second liquid crystal cell 120, and causes the polarization axis to change from the x-axis direction to the y-axis direction. Furthermore, the second polarization component 320, which changes the polarization axis from the x-axis to the y-axis, diffuses along the y-axis on the side of the second substrate 121-2. On the other hand, the first polarization component 310, which diffuses within the first liquid crystal cell 110 and changes the polarization axis from the x-axis to the y-axis, does not diffuse and changes the polarization axis from the y-axis to the x-axis. Thus, light incident on the optical element 10 diffuses along both the x-axis and y-axis as the first polarization component 310 passes through the first liquid crystal cell 110, and diffuses along both the x-axis and y-axis as the second polarization component 320 passes through the second liquid crystal cell 120. Therefore, the light transmitted through the optical element 10 can form a rectangularly extended light distribution pattern.

[0141] The above examples illustrate several light distribution patterns, but the light distribution angle, which represents the distribution of light, can be controlled by the magnitude of the voltage applied to the transparent electrode. For example, increasing the voltage applied to the transparent electrode increases the light distribution angle, resulting in a light distribution pattern with further light diffusion. Alternatively, the light distribution angle can also be controlled, for example, by the inter-substrate distance d or the pitch p.

[0142] [4. Relationship between inter-substrate distance and pitch]

[0143] Reference Figure 11 The relationship between the distance d between substrates and the pitch p is explained in detail.

[0144] Figure 11 This is a graph showing the relative brightness (relative brightness at 0 degrees) of the front surface relative to d / p in the liquid crystal cell of the optical element 10 according to one embodiment of the present invention. Figures 4A to 5B As shown, the substrate distance d is the distance between the first substrate 111-1 and the second substrate 111-2 of the first liquid crystal unit 110 (or, the distance between the first substrate 121-1 and the second substrate 121-2 of the second liquid crystal unit 120). Additionally, the pitch p is... Figure 3A The first pitch p1 shown (or Figure 3B The second pitch p2 is shown. In addition, the front relative brightness is the brightness of the light emitted from the second substrate 111-2 in the vertical direction (0 degrees) of the light incident from the first substrate 111-1 and emitted from the second substrate 111-2. Figure 11 The graph shown normalizes the light intensity to 1 when there are no optical elements 10 (only the light source). Therefore Figure 11 The y-axis of the curve shown can also be called the relative brightness ratio when the brightness without optical element 10 is set to 1.

[0145] In addition, it was obtained Figure 11 The liquid crystal cell in the graph shown has a first transparent electrode 112-1 and a second transparent electrode 112-2 formed on the first substrate 111-1, but a third transparent electrode 112-3 and a fourth transparent electrode 112-4 are not formed on the second substrate 111-2. Furthermore, when measuring brightness, a low potential (0V) is applied to the first transparent electrode 112-1, and a high potential (30V) is applied to the second transparent electrode 112-2.

[0146] like Figure 11As shown, the relative brightness of the front side decreases as d / p increases, but the rate of decrease differs significantly between d / p < 1 and d / p ≥ 1. When d / p < 1, although the relative brightness of the front side decreases sharply as it approaches d / p = 1, a front brightness of approximately 0.2 to 0.4 is measured. This indicates that while the brightness decreases due to light diffusion by the liquid crystal cells, the diffusion is not sufficient. In contrast, when d / p ≥ 1, the relative brightness of the front side becomes below 0.1, and then remains stable even as d / p increases. This indicates that the liquid crystal cells diffuse light sufficiently when d / p ≥ 1. That is, excellent light diffusion can be obtained when d / p ≥ 1. Therefore, in the optical element 10, the substrate distance d and the pitch p preferably satisfy d / p ≥ 1, and more preferably d / p ≥ 2.

[0147] Furthermore, the high refractive index of transparent electrode materials can sometimes affect the transmittance of liquid crystal cells. Therefore, a small width of the transparent electrode is preferred. That is, the distance b between the electrodes ( Figure 3A or Figure 3B The distance between the first electrode (b1) or the distance between the second electrode (b2) shown is preferably the width a of the transparent electrode. Figure 3A or Figure 3B The first width a1 or the second width a2 shown is less than or equal to the first width a1 or the second width a2 shown. For example, if the distance b between electrodes is expressed in terms of its relationship with the pitch p, then it is preferable to satisfy p / 2≤b.

[0148] As explained above, the optical element 10 of this embodiment has two liquid crystal units. By controlling the voltage applied to each transparent electrode, the light distribution or light distribution pattern of the light transmitted through the optical element 10 can be easily controlled.

[0149] <Second embodiment>

[0150] Reference Figure 12 The configuration of a lighting device 20 according to one embodiment of the present invention will be described.

[0151] Figure 12 This is a schematic diagram illustrating the configuration of a lighting device 20 according to one embodiment of the present invention. Figure 12 As shown, the lighting device 20 includes an optical element 10, a light source 210, a convex lens 220, and a reflector 230. The convex lens 220 is disposed between the optical element 10 and the light source 210. In addition, the reflector 230 is disposed in a manner that surrounds the space between the light source 210 and the convex lens 220.

[0152] Light source 210 can emit light. For example, a light bulb, fluorescent lamp, cold cathode tube, light-emitting diode (LED), or laser diode (LD) can be used as the light source 210. Preferably, the light source 210 of the lighting device 20 is an LED. The lighting device 20 using a high-efficiency LED as the light source 210 has high brightness and low power consumption. Furthermore, LEDs and LDs include organic light-emitting diodes (OLEDs) and organic laser diodes (OLDs), respectively.

[0153] The convex lens 220 can focus the light irradiated from the light source 210 and cause the focused light to be incident on the optical element 10.

[0154] Reflector 230 can reflect light incident from light source 210 and cause the reflected light to enter the convex lens. The shape of reflector 230 is, for example, generally conical, but not limited to this. In addition, the surface of reflector 230 can be flat or curved.

[0155] Furthermore, the lighting device 20 may also include a control unit that controls the voltage applied to the transparent electrode, enabling the formation of various light distribution patterns.

[0156] As explained above, the lighting device 20 of this embodiment includes an optical element 10, so the light distribution or light distribution pattern of the light emitted from the lighting device 20 can be easily controlled.

[0157] It should be understood that those skilled in the art can conceive of various modifications and alterations within the scope of the present invention, and these modifications and alterations also fall within the scope of the present invention. For example, solutions obtained by appropriately adding, deleting, or designing the constituent elements of the above embodiments, or solutions obtained by adding, omitting, or changing the conditions of processes, are included within the scope of the present invention as long as they possess the spirit of the present invention.

[0158] Furthermore, it should be understood that other effects resulting from the form described in this embodiment, or effects that can be readily conceived by those skilled in the art, are naturally effects brought about by the present invention.

[0159] Explanation of reference numerals in the attached figures

[0160] 10: Optical element; 20: Illumination device; 110: First liquid crystal unit; 111-1: First substrate; 111-2: Second substrate; 112-1: First transparent electrode; 112-2: Second transparent electrode; 112-3: Third transparent electrode; 112-4: Fourth transparent electrode; 113: Liquid crystal layer; 114-1: First alignment film; 114-2: Second alignment film; 115: Sealing material; 116-1: First wiring; 116-2: Second wiring; 116-3: Third wiring; 116-4: Fourth wiring; 116-5: Fifth wiring. Line, 116-6: Sixth wiring, 120: Second liquid crystal unit, 121-1: First substrate, 121-2: Second substrate, 122-1: First transparent electrode, 122-2: Second transparent electrode, 122-3: Third transparent electrode, 122-4: Fourth transparent electrode, 123: Liquid crystal layer, 124-1: First alignment film, 124-2: Second alignment film, 125: Sealing material, 130: Optical elastic resin layer, 210: Light source, 220: Convex lens, 230: Reflector, 310: First polarization component, 320: Second polarization component.

Claims

1. An optical element comprising a first liquid crystal unit and a second liquid crystal unit, wherein light incident on the first liquid crystal unit includes a first polarization component having a polarization axis in a first direction and a second polarization component having a polarization axis in a second direction intersecting the first direction, and the second liquid crystal unit is stacked on the first liquid crystal unit such that the light after passing through the first liquid crystal unit is incident thereon, wherein... The first liquid crystal unit and the second liquid crystal unit each include: First substrate; A first transparent electrode and a second transparent electrode are alternately arranged on the first substrate along the first direction and extend respectively in the second direction; A first orientation film covers the first transparent electrode and the second transparent electrode, and has an orientation direction in the first direction; Second substrate; The third transparent electrode and the fourth transparent electrode are alternately arranged on the second substrate along the second direction and extend in the first direction, respectively; A second alignment film, covering the third and fourth transparent electrodes, and having an alignment direction in the second direction; and A liquid crystal layer is located between the first substrate and the second substrate. The long axes of the liquid crystal molecules within the liquid crystal layer are oriented in a manner that varies from the first substrate side toward the second substrate side, and from the first direction toward the second direction, following the orientation directions of the first alignment film and the second alignment film. The second substrate of the first liquid crystal cell is adjacent to the first substrate of the second liquid crystal cell. In the disconnected state where no potential is applied to the first transparent electrode to the fourth transparent electrode of each of the first and second liquid crystal cells, In each of the first and second liquid crystal cells, when light passes through the liquid crystal layer from the first substrate toward the second substrate, the polarization axes of the first and second polarization components change, such that the polarization axes of the first and second polarization components respectively become the polarization axes of the second and first polarization components. When the potential difference between the first transparent electrode and the second transparent electrode of each of the first and second liquid crystal cells is connected, In the first liquid crystal cell, when light passes through the liquid crystal layer from the first substrate toward the second substrate, the polarization axes of the first polarization component and the second polarization component change, so that the polarization axes of the first polarization component and the second polarization component become the polarization axes of the second polarization component and the first polarization component, respectively, and the first polarization component diffuses along the first direction on the first substrate side. In the second liquid crystal cell, when the light passes through the liquid crystal layer from the first substrate toward the second substrate, the polarization axes of the first polarization component and the second polarization component change, so that the polarization axis of the first polarization component and the polarization axis of the second polarization component change to the polarization axis of the second polarization component and the polarization axis of the first polarization component, respectively, and the second polarization component diffuses along the first direction on the first substrate side.

2. The optical element according to claim 1, wherein, The second direction is orthogonal to the first direction.

3. The optical element according to claim 1 or 2, wherein, The substrate distance d between the first substrate and the second substrate and the first pitch p1 between the first transparent electrode and the second transparent electrode satisfy d / p1≥1.

4. The optical element according to claim 3, wherein, The condition d / p1≥2 is satisfied.

5. The optical element according to claim 3, wherein, The first pitch p1 and the first electrode distance b1 between the first transparent electrode and the second transparent electrode satisfy p1 / 2≤b1.

6. The optical element according to claim 3, wherein, The distance d between the substrates and the second pitch p2 between the third transparent electrode and the fourth transparent electrode satisfy d / p2≥1.

7. The optical element according to claim 6, wherein, The condition d / p²≥2 is satisfied.

8. The optical element according to claim 6, wherein, The second pitch p2 and the second electrode distance b2 between the third transparent electrode and the fourth transparent electrode satisfy p2 / 2≤b2.

9. The optical element according to claim 1, wherein, The second substrate of the first liquid crystal unit is adjacent to the first substrate of the second liquid crystal unit through an optical elastic resin layer.

10. The optical element according to claim 1, wherein, The first transparent electrode, the second transparent electrode, the third transparent electrode, and the fourth transparent electrode are each subjected to different voltages.

11. The optical element according to claim 1, wherein, When viewed from above, The first transparent electrode of the first liquid crystal cell overlaps with the first transparent electrode of the second liquid crystal cell along the entire extension direction. The second transparent electrode of the first liquid crystal cell overlaps with the second transparent electrode of the second liquid crystal cell throughout the entire extension direction. The third transparent electrode of the first liquid crystal cell overlaps with the third transparent electrode of the second liquid crystal cell throughout the entire extending direction. The fourth transparent electrode of the first liquid crystal cell overlaps with the fourth transparent electrode of the second liquid crystal cell throughout the entire extension direction.

12. The optical element according to claim 1, wherein, When viewed from above, The first transparent electrode of the first liquid crystal cell and the first transparent electrode of the second liquid crystal cell overlap approximately in the same direction along the entire extension. The second transparent electrode of the first liquid crystal cell overlaps with the second transparent electrode of the second liquid crystal cell in a substantially consistent manner along the entire extension direction. The third transparent electrode of the first liquid crystal cell and the third transparent electrode of the second liquid crystal cell overlap approximately in the same direction along the entire extension. The fourth transparent electrode of the first liquid crystal cell and the fourth transparent electrode of the second liquid crystal cell overlap approximately in the same direction along the entire extension.

13. A lighting device, comprising: light source; as well as The optical element according to any one of claims 1 to 12.

14. The lighting device according to claim 13, wherein, The lighting device also includes a convex lens between the light source and the optical element.

15. The lighting device according to claim 13 or 14, wherein, The lighting device further includes a reflector that reflects light from the light source so that it is incident on the optical element.

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