Lighting device

Abstract

To provide a technology capable of readily controlling irradiation to a desired region (direction in which light source is inclined) and diffusion by a liquid crystal lens instead of irradiation only in one direction.SOLUTION: A lighting device includes: a liquid crystal lens including a principal surface and a rear surface opposite to the principal surface; and a plurality of collimated light source devices disposed on a side of the rear surface of the liquid crystal lens and configured to be capable of irradiating the rear surface with collimated light. Each of the collimated light source devices is configured to be capable of adjusting an angle between an optical axis of collimated light and the rear surface.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a lighting device, and is particularly applicable to a lighting device equipped with a liquid crystal lens. [Background technology]

[0002] An illumination device equipped with a liquid crystal lens is proposed, for example, in Japanese Patent Application Laid-Open No. 2022-126144. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-126144 Summary of the Invention [Problem to be solved by the invention]

[0004] The present inventors have studied an illumination device that combines a liquid crystal lens with multiple collimated light sources that emit collimated light (parallel light). This illumination device is configured so that multiple collimated light sources are placed directly below a rectangular, flat (or planar) liquid crystal lens, with the angle between the front (or back) of the liquid crystal lens and the optical axis of the light emitted by the collimated light sources (collimated light) being 90 degrees. In this case, it was found that the diffusion of the light emitted by the liquid crystal lens only changes in a limited area based on the center of the light emitted, and that a separate unit is required to emit light in a direction other than the center of the light emitted.

[0005] Therefore, it has been found that in a lighting device that is capable of irradiating in different directions, the units that make up the lighting device become larger, or it becomes necessary to install a plurality of lighting devices.

[0006] An object of the present disclosure is to provide a technology that allows for easy control of irradiation in a desired area (the direction in which the light source is tilted) and diffusion by a liquid crystal lens, rather than irradiation in only one direction.

[0007] Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. [Means for solving the problem]

[0008] A brief summary of the representative aspects of the present invention is as follows.

[0009] That is, the lighting device a liquid crystal lens having a main surface and a back surface opposite to the main surface; a plurality of collimated light source devices arranged on the rear surface side of the liquid crystal lens and configured to be able to irradiate the rear surface with collimated light, Each of the plurality of collimated light source devices is configured so that the angle between the optical axis of the collimated light and the rear surface is adjustable. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating a lighting device according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating a light source used in the lighting device of FIG. [Figure 3] FIG. 3 is a diagram for explaining examples (EX12, EX13, EX14) of inclination of a plurality of light sources in the lighting device of FIG. [Figure 4] FIG. 4 is a diagram illustrating the first installation example EX11 of FIG. [Figure 5] FIG. 5 is a diagram illustrating a second installation example EX12 of FIG. [Figure 6] FIG. 6 is a diagram illustrating the third installation example EX13 of FIG. [Figure 7] FIG. 7 is a diagram illustrating the fourth installation example EX14 of FIG. [Figure 8] FIG. 8 is a cross-sectional view illustrating the principle of a liquid crystal lens. [Figure 9] FIG. 9 is an exploded perspective view showing this lens configuration. [Figure 10]FIG. 10 shows a case where a concave lens is formed by a liquid crystal lens. [Figure 11] FIG. 11 is a detailed cross-sectional view of the liquid crystal lens. [Figure 12] FIG. 12 is a plan view showing the shapes of the first electrode formed on the first substrate and the second electrode formed on the counter substrate. [Figure 13] FIG. 13 is a perspective view showing the configuration of the first liquid crystal lens and the second liquid crystal lens. [Figure 14] FIG. 14 is a cross-sectional view showing a state in which the first liquid crystal lens and the second liquid crystal lens are stacked. [Figure 15] FIG. 15 is a perspective view showing a configuration in which four liquid crystal lens panels are stacked. [Figure 16] FIG. 16 is a plan view of the liquid crystal lens. [Figure 17] FIG. 17 shows an example of the shape of the light spot. [Figure 18] FIG. 18 is a plan view of a liquid crystal lens formed by arranging liquid crystal elements (lens elements) in a matrix. [Figure 19] FIG. 19 is a plan view of the lens element. [Figure 20] FIG. 20 is a cross-sectional view of a liquid crystal lens. [Figure 21] FIG. 21 is a diagram illustrating an example of the configuration of the diffusion directions of the regions (1), (2), (3), and (4) of the liquid crystal lens. [Figure 22] FIG. 22 is a diagram illustrating an example of the arrangement of a collimated light source device according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0011] Each embodiment of the present disclosure will be described below with reference to the drawings. The disclosure is merely an example, and appropriate modifications that a person skilled in the art can easily conceive while maintaining the gist of the invention are naturally included within the scope of the present disclosure. Furthermore, to clarify the explanation, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual embodiment, but these are merely examples and are not intended to limit the interpretation of the present disclosure. Furthermore, in this specification and each drawing, elements similar to those described above with reference to the previous drawings will be designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0012] (Embodiment) Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 is a diagram illustrating an illumination device according to an embodiment. FIG. 2 is a diagram illustrating a light source used in the illumination device of FIG. 1. FIG. 3 is a diagram illustrating installation examples (EX12, EX13, EX14) of the inclination of multiple light sources in the illumination device of FIG. 1. FIG. 4 is a diagram illustrating installation example EX11 of FIG. 3. FIG. 5 is a diagram illustrating installation example EX12 of FIG. 3. FIG. 6 is a diagram illustrating installation example EX13 of FIG. 3. FIG. 7 is a diagram illustrating installation example EX14 of FIG. 3.

[0013] 1 shows a conceptual perspective view and a top view of an illumination device 1. As shown in FIG. 1, the illumination device 1 is composed of a plurality of collimated light source devices 2 and a liquid crystal lens 100.

[0014] In the upper perspective view of FIG. 1 , dotted line 100D indicates the position where liquid crystal lens 100 would normally be disposed. In FIG. 1 , the position of liquid crystal lens 100 is shifted upward as indicated by arrow AM to facilitate understanding of the relative positions. Liquid crystal lens 100 has a main surface 100S and a back surface 100B opposite to main surface 100S. In this example, liquid crystal lens 100 has a rectangular, flat plate shape. Liquid crystal lens 100 can be configured, for example, by stacking thin liquid crystal lenses; however, in FIG. 1 , it is depicted as a single transparent sheet to avoid complicating the drawing.

[0015] The plurality of collimating light source devices 2 (21, 22, 23, 24) are arranged on the rear surface 100B side of the liquid crystal lens 100 and are configured to be able to irradiate collimated light (parallel light) onto the rear surface 100B. The collimated light emitted from the plurality of collimating light source devices 2 is irradiated onto the rear surface 100B of the liquid crystal lens 100, passes through the liquid crystal lens 100, and is emitted from the main surface 100S of the liquid crystal lens 100. In this example, the plurality of collimating light source devices 2 are composed of a first collimating light source device 21, a second collimating light source device 22, a third collimating light source device 23, and a fourth collimating light source device 24. As will be described later, the liquid crystal lens 100 can electrically perform lens functions of various shapes, making it easy to obtain light spots of various shapes for the collimated light.

[0016] The length (depth) LX of the lighting device 1 (or the liquid crystal lens 100) in the first direction X is, for example, 53 mm, the length (width) LY of the second direction Y intersecting (perpendicular to) the first direction X is, for example, 53 mm, and the length (height) of the third direction Z intersecting (perpendicular to) the first direction X and the second direction Y is, for example, 25 mm.

[0017] 1, the plurality of collimating light source devices 2 (21, 22, 23, 24) are configured to be rotatable about rotation axes R21, R22, R23, R24. This makes it possible to adjust the angle of the optical axis of collimated light emitted from the plurality of collimating light source devices 2 (21, 22, 23, 24) relative to the rear surface 100B of the liquid crystal lens 100.

[0018] Next, the collimator light source devices 2 (21, 22, 23, 24) used in the illumination device 1 will be described with reference to Fig. 2. In Fig. 2, the collimator light source device 21 will be described as a representative example. The other collimator light source devices 22, 23, 24 can also have a similar configuration to the collimator light source device 21.

[0019] FIG. 2 shows a conceptual diagram in the lateral direction illustrating the configuration of the collimated light source device 21, and a schematic diagram illustrating the rotation direction.

[0020] As shown in the conceptual diagram in the horizontal direction, the collimated light source device 21 includes a light-emitting element LED that emits light, a drive device 21DD that controls the light-emitting and non-emitting states (ON / OFF control) of the light-emitting element LED and controls the increase / decrease in the amount of light when it emits light, and a rotation device 21RD that rotates the collimated light source device 21 about a rotation axis R21. The light-emitting element LED can be, for example, a light-emitting diode element.

[0021] When the driving device 21DD drives the light-emitting element LED, the light-emitting element LED emits light. When the driving device 21DD stops driving the light-emitting element LED, the light-emitting element LED stops emitting light. The driving device 21DD can control the amount of light emitted by the light-emitting element LED by increasing or decreasing the voltage value of the driving voltage applied to the light-emitting element LED.

[0022] Light emitted from the light-emitting element LED is configured to be emitted as collimated light CL from the emission surface 21S of the collimating light source device 21. The collimated light CL can be configured to have, for example, an optical axis OA that is perpendicular to the emission surface 21S. To simplify the drawing, FIG. 1 omits the rotation devices and drive devices provided in the multiple collimating light source devices 2 (21, 22, 23, 24), but in practice, each collimating light source device (21, 22, 23, 24) is provided with a rotation device and a drive device.

[0023] As shown in the schematic diagram illustrating the rotation direction, the collimator light source device 21 can adjustably control the direction of the optical axis OA by using the rotation device 21RD. Three examples are shown here. In the first example EX1, the angle between the direction of the optical axis OA and the rear surface 100B of the liquid crystal lens 100 is 90 degrees. In the second example EX2, the angle between the direction of the optical axis OA and the rear surface 100B of the liquid crystal lens 100 is 110 degrees. In the third example EX3, the angle between the direction of the optical axis OA and the rear surface 100B of the liquid crystal lens 100 is 70 degrees. In the second example EX2, the optical axis OA and the exit surface 21S are inclined with respect to the outside of the lighting device 1. On the other hand, in the third example EX3, the optical axis OA and the exit surface 21S are inclined with respect to the inside (toward the center) of the lighting device 1. The outward direction of the lighting device 1 is the direction away from the center point CC of the lighting device 1 shown in the plan view of FIG. 1, and the inward direction of the lighting device 1 is the direction toward the center point CC of the lighting device 1.

[0024] An example of installation of a plurality of collimator light source devices 2 (21, 22, 23, 24) will be described with reference to FIGS.

[0025] FIG. 1 shows a first installation example EX11 of multiple collimating light source devices 21, 22, 23, and 24, in which the angle between the directions of all optical axes OA of the collimating light source devices 21, 22, 23, and 24 and the rear surface 100B of the liquid crystal lens 100 is 90 degrees. The liquid crystal lens 100 is in a non-diffusing state. In the case of this first installation example EX11, as shown in FIG. 4, when viewed from direction A (view A) and direction B (view B) shown in FIG. 1, the angle between the directions of all optical axes OA of the collimating light source devices 21, 22, 23, and 24 and the rear surface 100B of the liquid crystal lens 100 is 90 degrees. In FIG. 4, C is an illumination image diagram of the state in which the collimating light source devices 21, 22, 23, and 24 emit collimated light when viewed from direction B (view B), and D is an illumination image diagram of the collimated light when viewed from directly above the lighting device 1. In D, the four spots appear to overlap to a relatively large extent.

[0026] In the second installation example EX12 of FIG. 3, the angle between the directions of all optical axes OA of the collimating light source devices 21, 22, 23, and 24 and the rear surface 100B of the liquid crystal lens 100 is 70 degrees. The liquid crystal lens 100 is in a non-diffusing state. In the case of this second installation example EX12, as shown in FIG. 5, when viewed from direction A (view A) and direction B (view B) shown in FIG. 1, the angle between the directions of all optical axes OA of the collimating light source devices 21, 22, 23, and 24 and the rear surface 100B of the liquid crystal lens 100 is 70 degrees. In FIG. 5, C is an illumination image of the state in which the collimating light source devices 21, 22, 23, and 24 emit collimated light when viewed from direction B (view B), and D is an illumination image of the collimated light when viewed from directly above the lighting device 1. In D, the four spots appear to overlap only a relatively small portion.

[0027] In the third installation example EX13 of FIG. 3, the angle between the directions of all optical axes OA of collimating light source devices 21, 22, 23, and 24 and rear surface 100B of liquid crystal lens 100 is 110 degrees. Liquid crystal lens 100 is in a non-diffusing state. In the case of this third installation example EX13, as shown in FIG. 6, when viewed from direction A (view A) and direction B (view B) shown in FIG. 1, the angle between the directions of all optical axes OA of collimating light source devices 21, 22, 23, and 24 and rear surface 100B of liquid crystal lens 100 is 110 degrees. In FIG. 6, C is an illumination image of the state in which collimating light source devices 21, 22, 23, and 24 emit collimated light when viewed from direction B (view B), and D is an illumination image of collimated light when viewed from directly above lighting device 1. The four spots appear to be spaced apart and do not overlap.

[0028] In the fourth installation example EX14 of FIG. 3 , the angle between the optical axis OA of collimating light source devices 22 and 24 and the rear surface 100B of liquid crystal lens 100 is 90 degrees, and the angles between the optical axis OA of collimating light source devices 21 and 23 and the rear surface 100B of liquid crystal lens 100 are 110 degrees and 70 degrees, respectively. The optical axis of collimating light source device 21 faces toward the outside of lighting device 1, and the optical axis of collimating light source device 23 faces toward the inside of lighting device 1. In other words, the exit surface of collimating light source device 21 and the exit surface of collimating light source device 23 face in the same direction. Liquid crystal lens 100 is in a non-diffusing state. In FIG. 7 , C is an illumination image diagram of collimating light source devices 21, 22, 23, and 24 emitting collimated light when viewed from direction B (view B), and D is an illumination image diagram of collimated light when viewed from directly above lighting device 1. In D, two spots (spots of collimated light source devices 21 and 23) appear to overlap in the Y direction, and the other two spots (spots of collimated light source devices 22 and 24) appear to overlap in the X direction, and the two spots (spots of collimated light source devices 21 and 23) appear to partially overlap with the other two spots (spots of collimated light source devices 22 and 24).

[0029] In this manner, a rotation device that enables adjustment of the angle between the direction of the optical axis OA of each of the collimator light source devices 21, 22, 23, and 24 and the rear surface 100B of the liquid crystal lens 100 is provided in each of the collimator light source devices.

[0030] As a result, the optical axes of the collimated light from collimator light source devices 21, 22, 23, and 24 are arranged at an angle rather than 90 degrees relative to the surface (main surface or back surface) of liquid crystal lens 100. This configuration solves the problem that, in a combination of liquid crystal lens 100 and collimator light source devices 21, 22, 23, and 24, even when collimator light source devices 21, 22, 23, and 24 are arranged directly below liquid crystal lens 100, the irradiated light has the same shape regardless of the number of lamps in the collimator light source device, and it becomes possible to irradiate collimated light in a desired area (the direction in which the collimator light source device is tilted) rather than irradiating collimated light in only one direction.

[0031] Furthermore, in the lighting device 1 according to the embodiment that allows illumination in different directions, the units that make up the lighting device 1 can be made smaller without increasing in size, and there is also the advantage that there is no need to install multiple lighting devices.

[0032] Although the above describes an example configuration in which a rotation device 21RD is provided to rotate the collimator light source device 21 about the rotation axis R21, the rotation device is not limited to this. Of course, the rotation device may be configured to be able to tilt the collimated light in any direction. That is, each collimator light source device (21, 22, 23, 24) may be provided with an arbitrary direction rotation device so that the collimated light of each of the collimator light source devices 21, 22, 23, 24 can be tilted in any direction in the first direction X and the second direction Y.

[0033] Next, the liquid crystal lens 100 will be described with reference to the drawings.

[0034] Figure 8 is a cross-sectional view illustrating the principle of liquid crystal lens 100. In Figure 8, collimated light is incident from the left side of liquid crystal layer 300. P in Figure 8 indicates the polarization direction of the incident light. The polarization direction of normal light is randomly distributed, but liquid crystals have anisotropy in their refractive index, so Figure 8 shows the behavior of light polarized in the P direction.

[0035] In Fig. 8, liquid crystal molecules 301 in liquid crystal layer 300 are aligned by electrodes so that the tilt increases toward the periphery of liquid crystal layer 300. Liquid crystal molecules 301 have an elongated shape, and the effective refractive index of liquid crystal molecules 301 in the long axis direction is greater than the effective refractive index of liquid crystal molecules 301 in the short axis direction. As a result, the refractive index increases toward the periphery of liquid crystal layer 300, forming a convex lens. The dotted line in Fig. 8 represents the light wavefront WF, and f is the focal length of the lens.

[0036] Because liquid crystals have anisotropy in refractive index, forming a lens requires a second lens that acts on light polarized in a direction perpendicular to the polarization direction of the light that the first lens acts on. Figure 9 is an exploded perspective view showing this lens configuration. In Figure 9, the parallelogram on the left represents the wavefront of the light. In other words, light polarized in the X and Y directions enters liquid crystal layer 300. First liquid crystal lens 110 acts on X-polarized light, and second liquid crystal lens 120 acts on Y-polarized light.

[0037] 9, the initial alignment directions of liquid crystal molecules 301 differ by 90 degrees between first liquid crystal lens 110 and second liquid crystal lens 120. The initial alignment of liquid crystal molecules 301 is determined by the alignment direction of the alignment film inside the liquid crystal lens. In other words, in FIG. 9, the alignment directions of the alignment films on the substrates on the light-incident side of the two liquid crystal lenses 110 and 120 are perpendicular to each other.

[0038] FIG. 10 shows a case where a concave lens is formed using a liquid crystal lens. In FIG. 10, light whose wavefront WF is parallel to the liquid crystal layer 300 and polarized in one direction enters the liquid crystal layer 300 from the left side. In FIG. 10, the liquid crystal molecules 301 in the liquid crystal layer 300 are most oriented near the optical axis by the electrodes, and the orientation angle decreases toward the periphery. With this lens configuration using liquid crystal orientation, the wavefront WF of the light that has passed through the liquid crystal layer 300 curves as shown by the dotted line in FIG. 10, forming a concave lens. Note that in the case of a concave lens, two liquid crystal lenses are still required, as shown in FIG. 9.

[0039] FIG. 11 is a detailed cross-sectional view of the liquid crystal lens 110. In FIG. 11, a first electrode 112 is formed on a TFT substrate 111, and a first alignment film 113 is formed covering the first electrode 112. The alignment direction of the first alignment film 113 determines which polarized light of incident light will be affected by the liquid crystal lens. A second electrode 116 is formed inside the counter substrate 115, and a second alignment film 117 is formed covering the second electrode 116. The relationship between the alignment directions of the first alignment film 113 and the second alignment film 117 is determined by the type of liquid crystal used. A liquid crystal layer 300 is sandwiched between the TFT substrate 111 and the counter substrate 115.

[0040] The left side of Fig. 12 is a plan view of the first electrode 112 formed on the first substrate 111. The first electrode 112 is in the form of concentric circles. Lead wiring 114 for applying voltage is connected to each circular electrode 112. The right side of Fig. 12 is a plan view showing the shape of the second electrode 116 formed on the opposing substrate 115. The second electrode 116 is a flat electrode and is formed over almost the entire surface of the opposing substrate 115.

[0041] In Fig. 12, lenses of various strengths can be formed by changing the voltage between the first electrode 112 and the second electrode 116. The examples in Fig. 11 and Fig. 12 have the feature that circular lenses can be easily formed because the first electrode 112 is formed in a concentric circle.

[0042] 11 and 12 is a lens that acts in one direction, for example, on polarized light PX. However, since light from the light-emitting element LED is polarized in all directions, a liquid crystal lens that acts on at least light PY polarized in a direction perpendicular to PX is required.

[0043] Fig. 13 is a perspective view showing this configuration. In Fig. 13, when light LL from the light-emitting element LED is incident from the left side, light polarized in the PX direction by first liquid crystal lens 110 is subjected to the action of the liquid crystal lens. Light polarized in the PY direction is not affected by first liquid crystal lens 110. Light polarized in the PY direction is subjected to the action of the liquid crystal lens by second liquid crystal lens 120. Light polarized in the PX direction is not affected by second liquid crystal lens 120. This allows both light polarized in the x direction and light polarized in the y direction to be subjected to the action of the liquid crystal lens.

[0044] 14 is a cross-sectional view showing a state in which first liquid crystal lens 110 and second liquid crystal lens 120 are laminated. First liquid crystal lens 110 and second liquid crystal lens 120 are bonded with transparent adhesive 200. In FIG. 14, the electrode configuration of second liquid crystal lens 120 is the same as that of first liquid crystal lens 110. That is, in second liquid crystal lens 120, third electrode 122 is formed on TFT substrate 121, and third alignment film 123 is formed thereon. Fourth electrode 126 is formed on opposing substrate 125, and fourth alignment film 127 is formed thereon.

[0045] The second liquid crystal lens 120 differs from the first liquid crystal lens 110 in the alignment direction of the alignment film 123. In FIG. 14, AL indicates the alignment direction of the alignment film 113. In FIG. 14, the alignment direction of the first alignment film 113 formed on the TFT substrate 111 of the first liquid crystal lens 110 is, for example, the x direction. The alignment direction of the third alignment film 123 formed on the TFT substrate 121 of the second liquid crystal lens 120 is, for example, the y direction. In other words, both light polarized in the x direction and light polarized in the y direction can be affected by the two liquid crystal lenses 110 and 120.

[0046] The orientation direction of second orientation film 117 formed on opposing substrate 115 of first liquid crystal lens 110 and the orientation direction of fourth orientation film 127 formed on opposing substrate 125 of second liquid crystal lens 120 are determined by the type of liquid crystal used as liquid crystal 300. In other words, second orientation film 117 of first liquid crystal lens 110 may be oriented in the same direction as first orientation film 113, or in a direction perpendicular to it. The relationship between third orientation film 123 and fourth orientation film 127 of second liquid crystal lens 120 is also the same.

[0047] However, since light from the light-emitting element LED is polarized in all directions, the liquid crystal lens may not be effective enough if it acts only on PX or PY polarized light. In this case, as shown in Figure 15, it is sufficient to add a liquid crystal lens 130 that acts on light P45 polarized at 45 degrees to the x direction, and a liquid crystal lens 140 that acts on light P135 polarized at 135 degrees to the x direction. In other words, liquid crystal lens 100 is composed of four overlapping liquid crystal lens panels (110, 120, 130, 140).

[0048] FIG. 16 is a plan view of the liquid crystal lens 100. In FIG. 16, the area of ​​the liquid crystal lens 100 is divided into areas (1), (2), (3), and (4) in accordance with the four collimating light source devices 23, 22, 21, and 24. That is, the liquid crystal lens 100 has a rectangular shape and is divided by diagonals into four triangular areas (1), (2), (3), and (4). The multiple collimating light source devices 23, 22, 21, and 24 are four collimating light source devices, and the four collimating light source devices 23, 22, 21, and 24 are arranged below the four areas (1), (2), (3), and (4) so ​​that one of the four collimating light source devices 23, 22, 21, and 24 is arranged corresponding to each of the four areas (1), (2), (3), and (4). By varying the lens action of the liquid crystal lens 100 in the collimating light source devices 2 (21, 22, 23, 24), it is possible to change the shape of the light spots from the four regions (1), (2), (3), and (4). If different lens actions are formed for all four regions (1), (2), (3), and (4) of the liquid crystal lens 100 shown in FIG. 16, different light spots can be obtained for all four regions (1), (2), (3), and (4). In addition, as described with reference to FIGS. 1 to 7, the four collimating light source devices 23, 22, 21, and 24 are configured to be rotatable along rotation axes R21-R24, so that the collimated light can be tilted in a desired direction.

[0049] Figure 17 shows examples of light spot shapes. Shape A is the light spot shape of collimated light that is not affected by the liquid crystal lens 100 (non-diffused). Shape B is the light spot shape of collimated light that is diffused by the liquid crystal lens 100. Shape C is the light spot shape of collimated light that is diffused only in the horizontal direction by the liquid crystal lens 100. Shape D is the light spot shape of collimated light that is diffused only in the vertical direction by the liquid crystal lens 100.

[0050] In this way, the shape of the light spot in each direction can be changed by changing the lens action of regions (1), (2), (3), and (4) in Fig. 16, but such a liquid crystal lens cannot be constructed using the liquid crystal lens shown in Fig. 11. Such a liquid crystal lens can be realized by forming liquid crystal elements (also called lens elements) 153 arranged in a matrix, as shown in Figs. 18 to 20.

[0051] In other words, with a matrix arrangement, a liquid crystal lens with any desired function can be configured by controlling the voltages (specifically, the signal line voltage and the scan line voltage) applied to the many lens elements arranged in a matrix. In Figure 18, the dotted diagonal lines are imaginary lines, and they separate the regions (1), (2), (3), and (4) shown in Figure 16.

[0052] 18, the TFT substrate 111 and the counter substrate 115 are bonded together at their peripheries with a sealant 150, and liquid crystal is sealed inside. The area where the TFT substrate 111 and the counter substrate 115 overlap becomes the lens area 170. The TFT substrate 111 is formed larger than the counter substrate 115, and the part of the TFT substrate 111 that does not overlap with the counter substrate 115 becomes the terminal area 160. A driver IC 165 that drives the liquid crystal lens and the like are arranged in the terminal area 160.

[0053] In the lens region 170 of Figure 18, scanning lines 151 extend in the horizontal direction (here, the x direction) and are arranged in the vertical direction (here, the y direction). Furthermore, signal lines 152 extend in the vertical direction and are arranged in the horizontal direction. Lens elements 153 including lens element electrodes (hereinafter simply referred to as element electrodes) 154 are formed in the region surrounded by the scanning lines 151 and the signal lines 152. A voltage is applied between the element electrodes and a common electrode formed on the opposing substrate to align the liquid crystal molecules in the required direction and refract light.

[0054] Fig. 19 is a plan view of lens element 153. In Fig. 19, element electrode 154 is formed in an area surrounded by scanning line 151 and signal line 152. A TFT (Thin Film Transistor) that is switched by a scanning signal is formed between element electrode 154 and signal line 152. The TFT is formed of a gate electrode 210 branching off from scanning line 151, a semiconductor film 211, a drain electrode 212 branching off from signal line 153, and a source electrode 213, and the source electrode 213 is connected to element electrode 154 via a through hole 214. The other liquid crystal lenses 120, 130, and 140 have a similar configuration.

[0055] Fig. 20 is a cross-sectional view of a liquid crystal lens. In Fig. 20, a liquid crystal layer 300 is sandwiched between a TFT substrate 111 on which element electrodes 154 are formed and a counter substrate 115 on which a common electrode 155 is formed. The TFT substrate 111 and the counter substrate 115 are bonded together with a sealant 150. Elements 153 of the liquid crystal lens are formed between the element electrodes 154 and the common electrode 155. The TFT substrate 111 is formed larger than the counter substrate 115, and the portion of the TFT substrate 111 that does not overlap with the counter substrate 115 forms a terminal region 160, and a driver IC 165 is arranged in the terminal region 160.

[0056] The liquid crystal lens shown in Figures 18 to 20 is formed and arranged in a matrix of multiple lens elements 153 that can control the alignment direction of the liquid crystal molecules in the liquid crystal layer, so that incident light can be expanded or contracted in any direction.

[0057] Fig. 21 is a diagram illustrating configuration examples of the diffusion directions of regions (1), (2), (3), and (4) of a liquid crystal lens. Basic configuration A in Fig. 21 shows regions (1), (2), (3), and (4) of liquid crystal lens 100, as well as the first direction X and the second direction Y. Configuration examples B to G in Fig. 21 will be explained using regions (1), (2), (3), and (4), as well as the first direction X and the second direction Y, shown in basic configuration A.

[0058] In configuration example B, all of areas (1), (2), (3), and (4) are in a non-diffused state, and the coherent light incident on areas (1), (2), (3), and (4) is not affected by the liquid crystal lens 100.

[0059] In configuration example C, all of regions (1), (2), (3), and (4) are diffused in the second direction Y (horizontal direction), and all of the coherent light incident on regions (1), (2), (3), and (4) is subject to horizontal diffusion. Configuration example C is sometimes called horizontal diffusion or combined vertical and horizontal diffusion.

[0060] In configuration example D, all of regions (1), (2), (3), and (4) are in a state of diffusion in the first direction X (vertical direction), and all of the coherent light incident on regions (1), (2), (3), and (4) is subjected to the effect of vertical diffusion. Configuration example D is sometimes called vertical diffusion or combined vertical and horizontal diffusion.

[0061] In configuration example E, regions (1) and (3) are diffused in the first direction X (vertical direction), and regions (2) and (4) are diffused in the second direction Y (horizontal direction). Coherent light incident on regions (1) and (3) is diffused in the vertical direction, and coherent light incident on regions (2) and (4) is diffused in the horizontal direction. Configuration example E is sometimes called all-around vertical diffusion.

[0062] In configuration example F, regions (1) and (3) are diffused in the second direction Y (horizontal direction), and regions (2) and (4) are diffused in the first direction X (vertical direction). Coherent light incident on regions (1) and (3) is subject to horizontal diffusion, and coherent light incident on regions (2) and (4) is subject to vertical diffusion. Configuration example F is sometimes referred to as full-circumference horizontal diffusion.

[0063] In the configuration example G, all of the regions (1), (2), (3), and (4) are in a state of diffusion in the second direction Y (horizontal direction) and the first direction X (vertical direction), and all of the coherent light incident on the regions (1), (2), (3), and (4) is subjected to the effect of diffusion in the horizontal and vertical directions. The configuration example D is sometimes called a total diffusion.

[0064] In this way, the liquid crystal lens 100 used in the lighting device 1 is combined with a unit that is divided into regions (in this example, divided into four regions: (1), (2), (3), and (4)). Furthermore, by individually controlling each region of the divided liquid crystal lens 100, various diffusion states can be achieved. In this example, the liquid crystal lens 100 is configured to be capable of non-diffusion, horizontal diffusion, vertical diffusion, and full diffusion.

[0065] Fig. 22 is a diagram illustrating an example of the arrangement of collimating light source devices according to a modified example. As shown in Fig. 22, the collimating light source devices 2 used in the illumination device 1 may be, for example, five (21, 22, 23, 24, 25) in which one collimating light source device 25 is added to the collimating light source devices (21, 22, 23, 24, 24) shown in Fig. 1. The number of collimating light source devices 2 is not limited to four or five, and can be increased or decreased as necessary.

[0066] The configuration of the lighting device 1 according to this embodiment can be summarized as follows.

[0067] (1) The liquid crystal lens 100 used can be combined with a unit that is divided into four areas (1), (2), (3), and (4) in this example. In addition, the divided areas of the liquid crystal lens 100 are configured so that the diffusion direction can be controlled individually.

[0068] (2) The collimating light source devices 2 are arranged at positions that have an angle other than 90 degrees relative to the surface (rear surface or main surface) of the liquid crystal lens 100. In other words, a rotation device (21RD) is provided for each collimating light source device so that the angle between the direction of the optical axis OA of the collimated light emitted from the collimating light source devices 2 and the rear surface 100B of the liquid crystal lens 100 can be set to an angle other than 90 degrees, such as 70 degrees or 110 degrees.

[0069] (3) The collimating light source devices 2 are arranged in each block of each liquid crystal lens 100 (areas (1), (2), (3), and (4)), and a driving device (21DD) is provided for each collimating light source device 2 so that each collimating light source device 2 can be turned on / off and the amount of light can be increased or decreased.

[0070] According to the embodiment, one or more of the following effects can be obtained.

[0071] (1) The lighting device 1 can illuminate not only in one direction but also in a limited area (in a direction in which the light source is tilted) and can control the diffusion by the liquid crystal lens 100.

[0072] (2) The lighting device 1 does not require a unit to be installed for each direction of illumination, resulting in a compact, unit-structured lighting device 1. Illumination that would normally require multiple units can now be achieved with just one lighting device 1, resulting in cost advantages.

[0073] (3) It is possible to create a variety of illumination conditions by changing the arrangement angle (including direction) of multiple collimating light source devices 2. The collimating light source devices 2 can be combined in four directions facing inward (installation example EX12 in Figure 3), four directions facing outward (installation example EX13 in Figure 3), two directions facing forward / two directions facing diagonally (installation example EX14 in Figure 3), and so on.

[0074] All lighting devices that can be implemented by a person skilled in the art by appropriately modifying the design of the lighting device described above as an embodiment of the present disclosure also fall within the scope of the present disclosure, as long as they include the gist of the present disclosure.

[0075] Within the scope of the concept of the present disclosure, a person skilled in the art may conceive of various modifications and alterations, and it is understood that these modifications and alterations also fall within the scope of the present disclosure. For example, to the above-described embodiments, a person skilled in the art may appropriately add, delete, or change the design of components, or add, omit, or change the conditions of steps, and these modifications are also included within the scope of the present disclosure as long as they include the gist of the present disclosure.

[0076] Furthermore, other effects and advantages brought about by the aspects described in this embodiment that are clear from the description in this specification or that can be appropriately thought of by a person skilled in the art are naturally understood to be brought about by the present disclosure.

[0077] Various disclosures can be formed by appropriately combining multiple components disclosed in the above embodiments. For example, some components may be omitted from all components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined. [Explanation of symbols]

[0078] 1: lighting device, 2, 23, 22, 21, 24: collimated light source device, 100... liquid crystal lens, 110... first liquid crystal lens, 111... TFT substrate, 112... first electrode, 113... first alignment film, 114... lead wiring, 115... opposing substrate, 116... second electrode, 117... second alignment film, 120... second liquid crystal lens, 121... TFT substrate, 122... third electrode, 123... third alignment film, 125... opposing substrate, 126... fourth electrode, 127... fourth alignment film, 150... sealing material, 151... scanning line, 152... signal line, 153... lens element, 154... element electrode, 155... common electrode, 160... terminal area, 165... driver IC, 170... lens area, 210...gate electrode, 211...semiconductor film, 212...drain electrode, 213...source electrode, 214...through hole, 300...liquid crystal layer, 301...liquid crystal molecules.

Claims

1. a liquid crystal lens having a main surface and a back surface opposite to the main surface; a plurality of collimated light source devices arranged on the rear surface side of the liquid crystal lens and configured to be able to irradiate the rear surface with collimated light, The illumination device is configured such that the angle between the optical axis of the collimated light and the rear surface of each of the plurality of collimated light source devices is adjustable.

2. 2. The lighting device according to claim 1, An illumination device, wherein each of the plurality of collimated light source devices can be controlled to emit light or not emit light.

3. 3. The lighting device according to claim 2, The liquid crystal lens is configured to be capable of non-diffusion, horizontal diffusion, vertical diffusion, and full diffusion.

4. 3. The lighting device according to claim 2, The liquid crystal lens is an illumination device in which a plurality of lens elements that can control the alignment direction of liquid crystal molecules in a liquid crystal layer are formed in a matrix.

5. 5. The lighting device according to claim 4, a liquid crystal lens having scanning lines extending in a first direction and signal lines extending in a second direction intersecting the first direction, and one lens element being formed in an area surrounded by the scanning lines and the signal lines.

6. 5. The lighting device according to claim 4, The liquid crystal lens is configured by stacking four liquid crystal lenses.

7. 5. The lighting device according to claim 4, The liquid crystal lens is It is rectangular in shape, Diagonals divide it into four triangular regions, the plurality of collimated light source devices, Four collimated light source devices, An illumination device, wherein the four collimated light source devices are arranged below the four regions so that one of the four collimated light source devices is arranged corresponding to each of the four regions.

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