Lighting equipment

Abstract

The purpose of the present embodiment is to provide a lighting device capable of radiating light to a desired location.　In the present embodiment, the lighting device is provided with: in a first area of a first light guiding plate, a first convex portion on a first primary face and a second convex portion on a second primary face opposite from the first primary face; and in a third area of a second light guiding plate, a third convex portion on a third primary face which counters the second primary face and a fourth convex portion on a fourth primary face opposite from the third primary face. The first and third convex portions have scalene triangle cross-sectional shapes, and the second and fourth convex portions have isosceles triangle cross-sectional shapes.

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE The present invention relates to a lighting device. [Background technology]

[0002] 2. Description of the Related Art Illumination devices equipped with a light source element and a light guide plate have been developed as surface-emitting illumination devices. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-173131 [Patent Document 2] JP 2002-296591 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present embodiment provides a lighting device capable of irradiating light to a desired position. [Means for solving the problem]

[0005] An illumination device according to an embodiment includes: A first lighting element including a first light source element and a first light guide plate having a first region and a second region; a second lighting element overlapping the first lighting element and including a second light source element and a second light guide plate having a third region and a fourth region; a liquid crystal cell overlapping the second lighting element; Equipped with The first light guide plate has a first side and a second side. The first light source element is disposed opposite the second side surface, the second region is located between the second side surface of the first light guide plate and the first region, the second light guide plate has a third side and a fourth side; the second light source element is disposed opposite to a third side surface of the second light guide plate, the fourth region is located between the fourth side surface of the second light guide plate and the third region, the fourth side surface is disposed closer to the second side surface than the first side surface; The first region of the first light guide plate is provided with a first convex portion on a first main surface and a second convex portion on a second main surface opposite to the first main surface, the third region of the second light guide plate is provided with a third convex portion on a third main surface facing the second main surface, and a fourth convex portion on a fourth main surface opposite to the third main surface; the liquid crystal cell includes a first substrate having a first electrode, a second substrate having a second electrode, and a liquid crystal layer provided between the first substrate and the second substrate; the first convex portion and the third convex portion each have a cross-sectional shape of a scalene triangle, The second convex portion and the fourth convex portion each have a cross-sectional shape of an isosceles triangle. Effect of the Invention

[0006] According to this embodiment, it is possible to provide a lighting device capable of irradiating light onto a desired position. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is an exploded perspective view showing a schematic configuration of a lighting device according to the present embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing a schematic configuration of the lighting device of the present embodiment. [Diagram 3] FIG. 3 is a schematic cross-sectional view showing the arrangement of a light guide plate and protrusions of the lighting device. [Figure 4A] FIG. 4A is a schematic enlarged cross-sectional view showing the shape of a convex portion of the lighting device. [Figure 4B] FIG. 4B is a schematic enlarged cross-sectional view showing the shape of a convex portion of the lighting device. [Figure 5A] FIG. 5A is a schematic enlarged cross-sectional view showing the shape of a convex portion of the lighting device. [Figure 5B] FIG. 5B is a schematic enlarged cross-sectional view showing the shape of a convex portion of the lighting device. [Figure 6] FIG. 6 is a perspective view showing the configuration of a liquid crystal lens. [Figure 7] FIG. 7 is an exploded perspective view of the liquid crystal lens shown in FIG. [Figure 8] FIG. 8 is a perspective view that illustrates a schematic configuration of the first liquid crystal cell of FIG. [Figure 9] FIG. 9 is a diagram illustrating a first liquid crystal cell in an off state (OFF) in which no electric field is applied to the liquid crystal layer. [Figure 10] FIG. 10 is a diagram illustrating a first liquid crystal cell in an on state (ON) where an electric field is applied across the liquid crystal layer. [Figure 11] FIG. 11 is a diagram showing the illuminance distribution of the light emitted from the lighting element. [Figure 12] FIG. 12 is a diagram showing the illuminance distribution of the light emitted from the lighting element. [Figure 13] FIG. 13 is a diagram showing the relationship between the zenith angle of an illumination element and the normalized luminous intensity of emitted light. [Figure 14] FIG. 14 is a diagram showing the relationship between the zenith angle of an illumination element and the normalized luminous intensity of emitted light. [Figure 15] FIG. 15 is a diagram showing the relationship between the angle of emission light and the luminous intensity of emission light in the lighting device of this embodiment. [Figure 16] FIG. 16 is a diagram showing the relationship between the angle of emission light and the luminous intensity of emission light in the lighting device of this embodiment. [Figure 17] FIG. 17 is a diagram showing the relationship between the angle of emission light and the luminous intensity of emission light in the lighting device of this embodiment. [Figure 18] FIG. 18 is a diagram showing the relationship between the angle of emission light and the luminous intensity of emission light in the lighting device of this embodiment. [Figure 19] FIG. 19 is a diagram showing the relationship between the angle of emission light and the luminous intensity of emission light in the lighting device of this embodiment. [Figure 20]FIG. 20 is a diagram showing the relationship between the angle of emission light and the luminous intensity of the emission light in the lighting device of this embodiment. [Figure 21] FIG. 21 is a diagram showing the relationship between the angle of emission light and the luminous intensity of emission light in the lighting device of this embodiment. [Figure 22] FIG. 22 is a diagram showing the relationship between the angle of emission light and the luminous intensity of emission light in the lighting device of this embodiment. [Figure 23] FIG. 23 is a diagram showing the relationship between the angle of emission light and the luminous intensity of emission light in the lighting device of this embodiment. [Figure 24] FIG. 24 is a diagram showing an example of application of the lighting device of this embodiment. [Diagram 25] FIG. 25 is a diagram showing an example of application of the lighting device of this embodiment. [Figure 26] FIG. 26 is a diagram showing an example of application of the lighting device of this embodiment. [Figure 27] FIG. 27 is a diagram showing an example of application of the lighting device of this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. Note that the disclosure is merely an example, and those who are skilled in the art can easily come up with appropriate modifications while maintaining the gist of the invention, which are naturally included in the scope of the present invention. In addition, in order to make the explanation clearer, the drawings may show the width, thickness, shape, etc. of each part in a schematic manner compared to the actual embodiment, but these are merely examples and do not limit the interpretation of the present invention. In addition, in this specification and each figure, elements similar to those described above with respect to the previous figures may be given the same reference numerals, and detailed explanations may be omitted as appropriate. Hereinafter, a lighting device according to an embodiment will be described in detail with reference to the drawings.

[0009] In this embodiment, the first direction X, the second direction Y, and the third direction Z are perpendicular to each other, but may intersect at an angle other than 90 degrees (90°). The direction toward the tip of the arrow of the third direction Z is defined as up or upward, and the direction opposite to the direction toward the tip of the arrow of the third direction Z is defined as down or downward. The first direction X, the second direction Y, and the third direction Z may also be called the X direction, the Y direction, and the Z direction, respectively.

[0010] Furthermore, in the case of "a second member above the first member" and "a second member below the first member," the second member may be in contact with the first member or may be located away from the first member. In the latter case, a third member may be interposed between the first and second members. On the other hand, in the case of "a second member above the first member" and "a second member below the first member," the second member is in contact with the first member.

[0011] Also, it is assumed that an observation position for observing the lighting device is located at the tip side of the arrow in the third direction Z, and a planar view refers to a view from this observation position toward the XY plane defined by the first direction X and the second direction Y. A cross-sectional view refers to a view of a cross section of the lighting device in the XZ plane defined by the first direction X and the third direction Z, or in the YZ plane defined by the second direction Y and the third direction Z.

[0012] Fig. 1 is an exploded perspective view showing a schematic configuration of the lighting device of the present embodiment, and Fig. 2 is a cross-sectional view showing a schematic configuration of the lighting device of the present embodiment. The illumination device ILD includes a reflection sheet REF, an illumination element IL1, an illumination element IL2, and a liquid crystal lens LNS, which are arranged in this order along the direction opposite to the third direction Z. Light emitted from the illumination device ILD is emitted downward. The reflection sheet REF and the illumination element IL1, the illumination elements IL1 and IL2, and the illumination element IL2 and the liquid crystal lens LNS are arranged to face each other, respectively.

[0013] The illumination element IL1 includes a first light guide plate LG1 and a plurality of first light source elements LSM1. The plurality of light source elements LSM1 are provided adjacent to a second side surface LG1s2 of the light guide plate LG1. The side surface LG1s2 is a light entrance portion into which light from the light source elements LSM1 is incident. No light source elements LSM1 are provided on a first side surface LG1s1 opposite to the side surface LG1s2.

[0014] The light guide plate LG1 has a first main surface LG1a facing the reflection sheet REF and a second main surface LG1b facing the light guide plate LG2. The main surface LG1b is provided on the opposite side of the main surface LG1a. The light guide plate LG1 has a center portion LG1c on a side parallel to the first direction X. Note that the center portion LG1c may be the center portion of a side of the effective light emission region of the light guide plate LG1, not the center portion of the parallel side of the light guide plate LG1. The effective light emission region is a region where light is emitted from the light guide plate LG1. The same applies to the light guide plate LG2. The region of the light guide plate LG1 adjacent to the side surface LG1s1 is defined as a first region AR11, and the region of the light guide plate LG1 adjacent to the side surface LG1s2 is defined as a second region AR12. In the region AR11, a plurality of first convex portions TV1a are provided on the main surface LG1a, and a plurality of second convex portions TV1b are provided on the main surface LG1b. In the region AR12, the convex portions TV1a and TV1b are not provided. That is, the convex portions TV1a and TV1b are not provided on the side surface LG1s2 on which the light source element LSM1 is provided, but are provided on the side surface LG1s1 on which the light source element LSM1 is not provided. The region AR11 extends from the side surface LG1s1, past the central portion LG1c, to the side surface LG1s2. The region AR12 occupies the region from the side surface LG1s2 to just before the central portion LG1c. In other words, the region AR11 includes the central portion LG1c, and the region AR12 does not include the central portion LG1c.

[0015] The multiple protrusions TV1a are arranged in a direction parallel to the first direction X, and each extends along a direction parallel to the second direction Y. The multiple protrusions TV1b are arranged in a direction parallel to the first direction X, and each extends along a direction parallel to the second direction Y. Each of the multiple protrusions TV1a has a triangular prism shape, and the cross-sectional shape is a scalene triangle. Each of the multiple protrusions TV1b has a triangular prism shape, and the cross-sectional shape is an isosceles triangle. The cross-sectional shapes of the protrusions TV1a and TV1b will be described in detail later. The protrusions TV1a and TV1b are formed integrally with the light guide plate LG1.

[0016] The illumination element IL2 includes a second light guide plate LG2 and a plurality of second light source elements LSM2. The plurality of light source elements LSM2 are provided adjacent to a third side surface LG2s1 of the light guide plate LG2. The side surface LG2s1 is a light entrance portion into which light from the light source elements LSM2 is incident. No light source element LSM2 is provided on a fourth side surface LG2s2 opposite to the side surface LG2s1. 1 and 2, the side surface LG2s2 is arranged side by side with the side surface LG1s2 along the third direction Z. However, this is not limited thereto, and the side surface LG2s2 may be arranged at a position closer to the side surface LG1s2 than the side surface LG1s1.

[0017] The light guide plate LG2 has a third main surface LG2a facing the light guide plate LG1 and a fourth main surface LG2b facing the liquid crystal lens LNS. The main surface LG2b is provided on the opposite side to the main surface LG2a. The center of the side of the light guide plate LG2 parallel to the first direction X is designated as LG2c. The region of the light guide plate LG2 adjacent to the side surface LG2s1 is defined as a third region AR21, and the region of the light guide plate LG2 adjacent to the side surface LG2s2 is defined as a fourth region AR22. In the region AR22, a plurality of third convex portions TV2a are provided on the main surface LG2a, and a plurality of fourth convex portions TV2b are provided on the main surface LG2b. The convex portions TV2a and TV2b are not provided in the region AR21. That is, the convex portions TV2a and TV2b are not provided on the side surface LG2s1 where the light source element LSM2 is provided, but are provided on the side surface LG2s2 where the light source element LSM2 is not provided. The region AR22 extends from the side surface LG2s2, past the central portion LG2c, to the side surface LG2s1. The region AR11 occupies the region from the side surface LG2s1 to just before the central portion LG2c. In other words, the region AR22 includes the central portion LG2c, and the region AR21 does not include the central portion LG2c. The regions AR21 and AR12 do not overlap each other in a planar view.

[0018] The multiple protrusions TV2a are arranged in a direction parallel to the first direction X, and each extends along a direction parallel to the second direction Y. The multiple protrusions TV2b are arranged in a direction parallel to the first direction X, and each extends along a direction parallel to the second direction Y. Each of the multiple protrusions TV2a has a triangular prism shape, and the cross-sectional shape is a scalene triangle. Each of the multiple protrusions TV2b has a triangular prism shape, and the cross-sectional shape is an isosceles triangle. The cross-sectional shapes of the protrusions TV2a and TV2b will be described in detail later. The protrusions TV2a and TV2b are formed integrally with the light guide plate LG1.

[0019] In the lighting element IL1, the light LT1 emitted from the light source element LSM1 enters the light guide plate LG1 from the side surface LG1s2. In the area AR12 where the convex portions TV1a and TV1b are not provided, the light LT1 is not emitted to the outside, but propagates within the light guide plate LG1 while being totally reflected. When the light LT1 reaches the area AR11, the reflection angle is changed by the convex portions TV1a and TV1b, and the light LT1 is emitted obliquely with respect to the third direction Z toward the lighting element IL2. Light LT1 incident on the illumination element IL2 passes through the light guide plate LG2, enters the liquid crystal lens from the light entrance surface LNSa of the liquid crystal lens, and exits from the light exit surface LNSb of the liquid crystal lens.

[0020] When the liquid crystal lens LNS is in the off state, the light LT1 incident on the liquid crystal lens LNS passes through as is and is emitted downward as light LT1p. When the liquid crystal lens LNS is in the on state, the light LT1 is polarized by the liquid crystal lens LNS and is emitted as polarized light LT1c. The configuration and operation of the liquid crystal lens LNS will be described in detail later.

[0021] In the illumination element IL2, the light LT2 emitted from the light source element LSM2 enters the light guide plate LG2 from the side surface LG2s1. In the region AR21 where the convex portions TV2a and TV2b are not provided, the light LT2 is not emitted to the outside, and propagates within the light guide plate LG2 while being totally reflected. When the light LT2 reaches the region AR22, the reflection angle is changed by the convex portions TV2a and TV2b, and the light LT2 is emitted obliquely with respect to the third direction Z toward the liquid crystal lens LNS.

[0022] If the liquid crystal lens LNS is in the off state, the light LT2 incident on the liquid crystal lens LNS passes through as is and is emitted downward as light LT2p. If the liquid crystal lens LNS is in the on state, the light LT2 is polarized by the liquid crystal lens LNS and is emitted as polarized light LT2c.

[0023] The angles at which the light LT1p and LT2p are emitted with respect to the third direction Z are defined as R1p and R2p, respectively. If the sum of the angles R1p and R2p is defined as Rp, the angle Rp is the light distribution angle of the emitted light from the illumination device ILD when the liquid crystal lens LNS is in the off state. Similarly, the angles at which polarized light LT1c and LT2c are emitted are R1c and R2c, respectively. If the sum of angles R1c and R2c is Rc, angle Rc is the light distribution angle of the emitted light from illumination device ILD when liquid crystal lens LNS is in the on state.

[0024] Angle Rp (=R1p+R2p) is greater than angle Rc (=R1c+R2c). Each of angles R1p and R2p is also greater than each of angles R1c and R2c. That is, light beams LT1p and LT2p are emitted further outward, and polarized light beams LT1c and LT2c are emitted further inward.

[0025] The angles R1p and R2p are each, for example, 45°. The angles R1c and R2c are each, for example, 22°. That is, the angle Rp is 90° and the angle Rc is 44°. In this way, the light distribution angle when the liquid crystal lens LNS is in the on state is smaller than the light distribution angle when the liquid crystal lens LNS is in the off state. In the lighting device ILD of this embodiment, it is possible to control the emitted illumination light to be in a desired direction by combining the lighting of the light source elements LSM1 and LSM2 of the lighting elements IL1 and IL2, and the on and off states of the liquid crystal lens LNS.

[0026] 3 is a schematic cross-sectional view showing the arrangement of the light guide plate and the protrusions of the lighting device. The region AR11 of the light guide plate LG1 overlaps with the region AR22 of the light guide plate LG2 in a planar view. That is, a part of the multiple protrusions TV1a and a part of the multiple protrusions TV2a overlap near the centers of the light guide plates LG1 and LG2 in a planar view. Conversely, the regions AR12 and AR21 do not overlap in a planar view.

[0027] Of the region AR11 of the light guide plate LG1, the region that overlaps with the region AR22 is referred to as the overlap region OR1, and of the region AR22, the region that overlaps with the region AR11 is referred to as the overlap region OR2. The light of the light source element LSM1 that enters from the side surface LG1s2 is gradually emitted by the multiple protrusions TV1a as it approaches the side surface LG1s1. In order to emit light from a region closer to the side surface LG1s1 than the center portion LG1c of the light guide plate LG1, the protrusions TV1a are also required in a region closer to the light entrance side than the center portion LG1c. The above also applies to the light guide plate LG2. Therefore, a protrusion TV2a is also required on the light incident side (side surface LG2s1 side) of the central portion LG2c of the light guide plate LG2.

[0028] At the end of the region AR11 (overlapping region OR1) on the side surface LG1s2 side, all of the incident light is emitted downward, resulting in a decrease in the brightness of the emitted light. Similarly, at the end of the region AR22 (overlapping region OR2) on the side surface LG2s1 side, all of the incident light is emitted, resulting in a decrease in the brightness of the emitted light. Therefore, by providing the overlapping regions OR1 and OR2, it is possible to compensate for the decreased brightness. This makes it possible to uniform the brightness of the emitted light from the light guide plates LG1 and LG2.

[0029] 4A and 4B are schematic enlarged cross-sectional views showing the shape of the protrusions of the lighting device. The cross-sectional shape of each of the protrusions TV1a of the light guide plate LG1 in the XZ plane is a scalene triangle (see FIG. 4A). Of the sides of the scalene triangle, the side that contacts the main surface LG1a of the light guide plate LG1 is designated as E1a1. The scalene triangle has sides E1a2 and E1a3 extending from the side E1a1. The angle formed by the sides E1a1 and E1a2 is designated as T1a1, the angle formed by the sides E1a1 and E1a3 is designated as T1a2, and the angle formed by the sides E1a2 and E1a3 is designated as T1a3.

[0030] As shown in FIG. 4A, the lengths of sides E1a1, E1a2, and E1a3 are all different. It is preferable that the angle T1a1 is 90° (90 degrees). That is, it is preferable that the scalene triangle is a right-angled triangle. If the angle T1a1 is 90°, the light incident on the convex portion TV1a can be efficiently reflected, which is preferable. However, the angle T1a1 is not limited to this and may be an angle close to 90°, for example, within a range of 80° to 90°.

[0031] Angle T1a2 is an acute angle, for example, 15 degrees. Angle T1a3 is an acute angle, for example, 75 degrees. Angles T1a2 and T1a3 may be appropriately determined depending on the light distribution angle of the emitted light, etc. The interval and pitch between adjacent convex portions TV1a are Tg1 and Tp1, respectively. The pitch Tp1 is the sum of the length of the side E1a1 and the interval Tg1. When the pitch Tp1 is a predetermined fixed value, the distribution of the convex portions TV1a can be controlled by changing the length of the side E1a1.

[0032] The cross-sectional shape of each of the protrusions TV1b of the light guide plate LG1 in the YZ plane is an isosceles triangle (see FIG. 4B). Of the sides of the isosceles triangle, the side that contacts the main surface LG1b of the light guide plate LG1 is designated as E1b1. The isosceles triangle has sides E1b2 and E1b3 extending from the side E1b1. The angle formed by the sides E1b1 and E1b2 is designated as T1b1, the angle formed by the sides E1b1 and E1b3 is designated as T1b2, and the angle formed by the sides E1b2 and E1b3 is designated as T1b3.

[0033] In the isosceles triangle, angles T1b1 and T1b2, which are base angles, are equal. Angle T1b3, which is an apex angle, may also be equal to angles T1b1 and T1b2. In other words, the isosceles triangle that is the cross-sectional shape of the protrusion TV1b may be an equilateral triangle.

[0034] 5A and 5B are schematic enlarged cross-sectional views showing the shape of the protrusions of the lighting device. The cross-sectional shape of each of the protrusions TV2a of the light guide plate LG2 in the XZ plane is a scalene triangle (see FIG. 5A). Of the sides of the scalene triangle, the side that contacts the main surface LG2a of the light guide plate LG2 is designated as E2a1. The scalene triangle has sides E2a2 and E2a3 extending from the side E2a1. The angle formed by the sides E2a1 and E2a2 is designated as T2a1, the angle formed by the sides E2a1 and E2a3 is designated as T2a2, and the angle formed by the sides E2a2 and E2a3 is designated as T2a3.

[0035] As shown in FIG. 5A, the lengths of sides E2a1, E2a2, and E2a3 are all different. It is preferable that the angle T2a1 is 90°. That is, it is preferable that the scalene triangle is a right-angled triangle. If the angle T2a1 is 90°, the light incident on the convex portion TV2a can be efficiently reflected, which is preferable. However, the angle T2a1 is not limited to this and may be an angle close to 90 degrees, for example, within a range of 80° to 90°.

[0036] The angle T2a2 is an acute angle, for example, 15°. The angle T2a3 is an acute angle, for example, 75°. The angles T2a2 and T2a3 may be appropriately determined depending on the light distribution angle of the emitted light, etc. The interval and pitch between adjacent convex portions TV2a are Tg2 and Tp2, respectively. The pitch Tp2 is the sum of the length of the side E2a1 and the interval Tg2. As with the convex portions TV1a, when the pitch Tp2 is set to a predetermined fixed value, the distribution of the convex portions TV2a can be controlled by changing the length of the side E2a1.

[0037] The cross-sectional shape of each of the protrusions TV1a of the light guide plate LG1 and the cross-sectional shape of each of the protrusions TV2a of the light guide plate LG2 are arranged at positions that are line-symmetrical with respect to a direction parallel to the YZ plane. In this embodiment, the lengths of the sides E1a1 and E2a1, the lengths of the sides E1a2 and E2a2, and the lengths of the sides E1a3 and E2a3 are all equal. The angles T1a1 and T2a1, the angles T1a2 and T2a2, and the angles T1a3 and T2a3 are equal in size, respectively.

[0038] The cross-sectional shape of each of the protrusions TV2b of the light guide plate LG2 in the YZ plane is an isosceles triangle (see FIG. 5B). Of the sides of the isosceles triangle, the side that contacts the main surface LG2b of the light guide plate LG2 is designated as E2b1. The isosceles triangle has sides E2b2 and E2b3 extending from the side E2b1. The angle formed by the sides E2b1 and E2b2 is designated as T2b1, the angle formed by the sides E2b1 and E2b3 is designated as T2b2, and the angle formed by the sides E2b2 and E2b3 is designated as T2b3.

[0039] In the isosceles triangle, angles T2b1 and T2b2, which are base angles, are equal. Angle T2b3, which is an apex angle, may also be equal to angles T2b1 and T2b2. In other words, the isosceles triangle that is the cross-sectional shape of the protrusion TV2b may be an equilateral triangle.

[0040] Here, the liquid crystal lens LNS will be described with reference to a perspective view of the liquid crystal lens shown in FIG. The liquid crystal lens LNS includes a first liquid crystal cell 10, a second liquid crystal cell 20, a third liquid crystal cell 30, and a fourth liquid crystal cell 40. The liquid crystal lens LNS according to this embodiment includes two or more liquid crystal cells, and is not limited to a configuration including four liquid crystal cells as in the example shown in FIG.

[0041] In the third direction Z, the fourth liquid crystal cell 40, the third liquid crystal cell 30, the second liquid crystal cell 20, and the first liquid crystal cell 10 are stacked in this order.

[0042] LT1 and LT2 emitted from the lighting element IL2 are transmitted through the fourth liquid crystal cell 40, the third liquid crystal cell 30, the second liquid crystal cell 20, and the first liquid crystal cell 10 in this order. As described later, the first liquid crystal cell 10, the second liquid crystal cell 20, the third liquid crystal cell 30, and the fourth liquid crystal cell 40 are configured to refract a portion of the polarized components of the incident light. The liquid crystal lens LNS can diffuse and focus the light.

[0043] FIG. 7 is an exploded perspective view of the liquid crystal lens shown in FIG. The first liquid crystal cell 10 includes a first transparent substrate S11, a second transparent substrate S21, a liquid crystal layer LC1, and a seal SE1. The first transparent substrate S11 and the second transparent substrate S21 are bonded together by the seal SE1. The liquid crystal layer LC1 is held between the first transparent substrate S11 and the second transparent substrate S21 and sealed by the seal SE1. An effective area AA1 capable of refracting incident light is formed inside the area surrounded by the seal SE1.

[0044] The first transparent substrate S11 has an extension portion EX1 extending outward beyond the second transparent substrate S21 along the first direction X, and an extension portion EY1 extending outward beyond the second transparent substrate S21 along the second direction Y. A flexible wiring substrate F as indicated by a dotted line is connected to at least one of the extension portion EX1 and the extension portion EY1.

[0045] The second liquid crystal cell 20 includes a first transparent substrate S12, a second transparent substrate S22, a liquid crystal layer LC2, and a seal SE2. An effective area AA2 is formed inside the area surrounded by the seal SE2. The first transparent substrate S12 has an extension portion EX2 and an extension portion EY2. In the third direction Z, the extension portion EX2 overlaps the extension portion EX1, and the extension portion EY2 overlaps the extension portion EY1. A flexible wiring board is connected to at least one of the extension portion EX2 and the extension portion EY2, but the flexible wiring board is not shown in the other second liquid crystal cell 20 to fourth liquid crystal cell 40.

[0046] The third liquid crystal cell 30 includes a first transparent substrate S13, a second transparent substrate S23, a liquid crystal layer LC3, and a seal SE3. An effective area AA3 is formed inside the area surrounded by the seal SE3. The first transparent substrate S13 has an extension portion EX3 and an extension portion EY3. The extension portion EY3 overlaps the extension portion EY2 in the third direction Z. The extension portion EX3 does not overlap the extension portion EX2 and is located on the opposite side to the extension portion EX2.

[0047] The fourth liquid crystal cell 40 includes a first transparent substrate S14, a second transparent substrate S24, a liquid crystal layer LC4, and a seal SE4. An effective area AA4 is formed inside the area surrounded by the seal SE4. The first transparent substrate S14 has an extension portion EX4 and an extension portion EY4. In the third direction Z, the extension portion EX4 overlaps the extension portion EX3, and the extension portion EY4 overlaps the extension portion EY3.

[0048] A transparent adhesive layer TA12 is disposed between the first liquid crystal cell 10 and the second liquid crystal cell 20. The transparent adhesive layer TA12 bonds the first transparent substrate S11 and the second transparent substrate S22 together. A transparent adhesive layer TA23 is disposed between the second liquid crystal cell 20 and the third liquid crystal cell 30. The transparent adhesive layer TA23 bonds the first transparent substrate S12 and the second transparent substrate S23 together. A transparent adhesive layer TA34 is disposed between the third liquid crystal cell 30 and the fourth liquid crystal cell 40. The transparent adhesive layer TA34 bonds the first transparent substrate S13 and the second transparent substrate S24 together.

[0049] The first transparent substrates S11 to S14 are each formed in a square shape and have the same size. For example, in the first transparent substrate S11, the sides SX and SY are perpendicular to each other, and the length of the side SX is the same as the length of the side SY. Therefore, when the first liquid crystal cell 10, the second liquid crystal cell 20, the third liquid crystal cell 30, and the fourth liquid crystal cell 40 are bonded to each other, as shown in FIG. 6, the sides along the first direction X overlap each other, and further, the sides along the second direction Y also overlap each other. It is also possible to make the second substrate, which has a shape substantially the same as the shape of the light transmitting region (effective region described later), square, and make the first substrate a polygonal shape other than a square, for example a rectangle. Also, a configuration in which one of the extensions of each liquid crystal cell is removed can be adopted.

[0050] Next, the configuration of each liquid crystal cell will be described in more detail. In the following, the first liquid crystal cell 10 will be described as an example among the multiple liquid crystal cells that make up the liquid crystal lens LNS, but the configurations of the other liquid crystal cells, from the second liquid crystal cell 20 to the fourth liquid crystal cell 40, are generally similar to that of the first liquid crystal cell 10, except for the extension direction of the charging electrodes.

[0051] FIG. 8 is a perspective view that diagrammatically illustrates the first liquid crystal cell 10 of FIG. The first liquid crystal cell 10 includes, in the effective area AA1, a first charging electrode E11A, a second charging electrode E11B, a first alignment film AL11, a third charging electrode E21A, a fourth charging electrode E21B, and a second alignment film AL21.

[0052] The first charging electrode E11A and the second charging electrode E11B are located between the first transparent substrate S11 and the first alignment film AL11, are spaced apart, and extend in the same direction. The first charging electrode E11A and the second charging electrode E11B may be in contact with the first transparent substrate S11, or an insulating film may be interposed between them. Alternatively, an insulating film may be interposed between the first charging electrode E11A and the second charging electrode E11B, and the first charging electrode E11A may be located in a layer different from the second charging electrode E11B.

[0053] A plurality of first charging electrodes E11A and a plurality of second charging electrodes E11B are arranged alternately in a first direction X. The plurality of first charging electrodes E11A are electrically connected to each other and configured to have the same voltage applied thereto. The plurality of second charging electrodes E11B are electrically connected to each other and configured to have the same voltage applied thereto. However, the voltage applied to the second charging electrodes E11B is controlled to be different from the voltage applied to the first charging electrode E11A.

[0054] The first alignment film AL11 covers the first charging electrode E11A and the second charging electrode E11B. The alignment treatment direction AD11 of the first alignment film AL11 is the first direction X. The alignment treatment of each alignment film may be a rubbing treatment or a photo-alignment treatment. The alignment treatment direction may be called the rubbing direction. In general, in a state where no voltage is applied to the liquid crystal layer (initial alignment state), liquid crystal molecules located near the alignment film are initially aligned in a predetermined direction by an alignment restriction force along the alignment treatment direction of the alignment film. That is, in the example shown here, the initial alignment direction of the liquid crystal molecules LM11 along the first alignment film AL11 is the first direction X. The alignment treatment direction AD11 intersects with the first charging electrode E11A and the second charging electrode E11B.

[0055] The third and fourth charging electrodes E21A and E21B are located between the second transparent substrate S21 and the second alignment film AL21, are spaced apart, and extend in the same direction. The third and fourth charging electrodes E21A and E21B may be in contact with the second transparent substrate S21, or an insulating film may be interposed between them. Alternatively, an insulating film may be interposed between the third and fourth charging electrodes E21A and E21B, and the third and fourth charging electrodes E21A and E21B may be located in a different layer from the fourth charging electrode E21B.

[0056] The multiple third charging electrodes E21A and the multiple fourth charging electrodes E21B are arranged alternately in the second direction Y. The multiple third charging electrodes E21A are electrically connected to each other and configured to be applied with the same voltage. The multiple fourth charging electrodes E21B are electrically connected to each other and configured to be applied with the same voltage. However, the voltage applied to the fourth charging electrode E21B is controlled to be different from the voltage applied to the third charging electrode E21A. In addition, the extension direction of the first charging electrode E11A and the second charging electrode E11B is perpendicular to the extension direction of the third charging electrode E21A and the fourth charging electrode E21B, which will be described in detail later.

[0057] The second alignment film AL21 covers the third band electrode E21A and the fourth band electrode E21B. The alignment treatment direction AD21 of the second alignment film AL21 is the second direction Y. That is, in the example shown here, the initial alignment direction of the liquid crystal molecules LM21 along the second alignment film AL21 is the second direction Y. In addition, the alignment treatment direction AD11 of the first alignment film AL11 and the alignment treatment direction AD21 of the second alignment film AL21 are perpendicular to each other. The alignment treatment direction AD21 intersects with the third band electrode E21A and the fourth band electrode E21B.

[0058] Here, the optical action of the first liquid crystal cell 10 will be described with reference to Fig. 9 and Fig. 10. Note that Fig. 9 and Fig. 10 only show configurations necessary for the description, such as the liquid crystal molecule LM1 in the vicinity of the first transparent substrate S11.

[0059] FIG. 9 is a diagram illustrating the first liquid crystal cell 10 in an off state (OFF) in which no electric field is applied to the liquid crystal layer LC1. In the liquid crystal layer LC1 in the off state, the liquid crystal molecules LM1 are initially aligned. In such an off state, the liquid crystal layer LC1 has a substantially uniform refractive index distribution. Therefore, the polarized component POL1, which is the light incident on the first liquid crystal cell 10, passes through the liquid crystal layer LC1 with almost no refraction (or diffusion).

[0060] 9, in the first liquid crystal cell 10, the initial alignment directions of the liquid crystal molecules in the liquid crystal layer LC1 cross at 90° between the first transparent substrates S11 and S21. The liquid crystal molecules in the liquid crystal layer LC1 are aligned in one of the first direction X and the second direction Y on the second transparent substrate S21 side. The liquid crystal molecules gradually change their orientation from the one direction to the other direction of the first direction X and the second direction Y as they move toward the first transparent substrate S11 side. The liquid crystal molecules are aligned in the other direction on the first transparent substrate S11 side.

[0061] The orientation of the polarized components changes in response to such a change in the alignment of the liquid crystal layer LC1. More specifically, the polarized component having a polarization axis on one side changes its polarization axis to the other side while passing through the liquid crystal layer LC1. On the other hand, the polarized component having a polarization axis on the other side changes its polarization axis to one side while passing through the liquid crystal layer LC1. Therefore, when viewed from the perspective of these mutually orthogonal polarized components, their polarization axes are swapped while passing through the first liquid crystal cell 10. Hereinafter, the action of changing the orientation of the polarization axis may be referred to as optical rotation.

[0062] FIG. 10 is a diagram illustrating the first liquid crystal cell 10 in an on state (ON) where an electric field is applied to the liquid crystal layer LC1. In the on-state, a potential difference occurs between the first charging electrode E11A and the second charging electrode E11B, forming an electric field in the liquid crystal layer LC1. For example, when the liquid crystal layer LC1 has a positive dielectric anisotropy, the liquid crystal molecules LM1 are oriented so that their major axes are aligned with the electric field. However, the range of the electric field between the first charging electrode E11A and the second charging electrode E11B is mainly about half the thickness of the liquid crystal layer LC1. Therefore, as shown in FIG. 10, in the liquid crystal layer LC1, in the range close to the first transparent substrate S11, there are formed a region where the liquid crystal molecules LM1 are oriented almost perpendicular to the substrate, a region where the liquid crystal molecules LM1 are oriented obliquely to the substrate, a region where the liquid crystal molecules LM1 are oriented almost horizontally to the substrate, and the like.

[0063] The liquid crystal molecules LM1 have a refractive index anisotropy Δn. Therefore, the liquid crystal layer LC1 in the on state has a refractive index distribution or retardation distribution according to the alignment state of the liquid crystal molecules LM1. Here, the retardation is expressed as Δn·d when the thickness of the liquid crystal layer LC1 is d. Note that in this embodiment, a positive type liquid crystal is used as the liquid crystal layer LC1, but it is also possible to use a negative type liquid crystal by considering the alignment direction, etc.

[0064] In such an on-state, the polarized component POL1 is diffused by the influence of the refractive index distribution of the liquid crystal layer LC1 when passing through the liquid crystal layer LC1. More specifically, a polarized component having a polarization axis in one of the first direction X and the second direction Y is diffused by the influence of the refractive index distribution of the liquid crystal layer LC1 and rotated in the other of the first direction X and the second direction Y. A polarized component having the other polarization axis is not influenced by the refractive index distribution, and passes through the liquid crystal layer LC1 without being diffused and rotated only in that one direction.

[0065] 10 has described the case where an electric field is formed by the potential difference between the first and second charging electrodes E11A and E11B, but it is desirable to also form an electric field by the potential difference between the third and fourth charging electrodes E21A and E21B when diffusing incident light in the first liquid crystal cell 10. This controls the alignment state of not only the liquid crystal molecules in the vicinity of the first transparent substrate S11 but also the liquid crystal molecules in the vicinity of the second transparent substrate S21, and forms a predetermined refractive index distribution in the liquid crystal layer LC1. More specifically, since the liquid crystal layer LC1 on the second transparent substrate S21 side also has a refractive index distribution, the polarized component rotated in the other of the first direction X and the second direction Y is diffused in the process of passing through the liquid crystal layer LC1. That is, the polarized component diffused on the first transparent substrate S11 side is further diffused on the second transparent substrate S21 side and emitted from the first liquid crystal cell 10. On the other hand, the polarized component rotated in one of the first direction X and the second direction Y in the process of passing through the liquid crystal layer LC1 is emitted from the first liquid crystal cell 10 without being affected by the refractive index distribution.

[0066] Such diffusion and rotation of the polarized light components also occurs in the second liquid crystal cell 20. That is, a polarized light component having a polarization axis in one of the first direction X and the second direction Y emitted from the light source changes its polarization axis from the one direction to the other direction of the first direction X and the second direction Y by passing through the first liquid crystal cell 10, and further changes its polarization axis from the other direction to the one direction by passing through the second liquid crystal cell 20.

[0067] Furthermore, if the liquid crystal molecules parallel to the polarized light component have a refractive index distribution during this process, the polarized light component is diffused in accordance with the refractive index distribution. Similarly, a polarized light component having a polarization axis in the other of the first direction X and the second direction Y emitted from the light source changes its polarization axis from the other to one of the first direction X and the second direction Y by passing through the first liquid crystal cell 10. Furthermore, the polarization axis changes from the one to the other by passing through the second liquid crystal cell 20. Furthermore, if the liquid crystal molecules parallel to the polarized light component have a refractive index distribution during this process, the polarized light component is diffused in accordance with the refractive index distribution. The same phenomenon occurs in the third liquid crystal cell 30 and the fourth liquid crystal cell 40, but since these are the first liquid crystal cell and the second liquid crystal cell rotated by 90 degrees, the polarized light components that have a diffusing effect are interchanged.

[0068] That is, in a configuration in which a first liquid crystal cell 10, a second liquid crystal cell 20, a third liquid crystal cell 30, and a fourth liquid crystal cell 40 are stacked, for example, the first liquid crystal cell 10 and the fourth liquid crystal cell 40 are configured to scatter (diffuse) the polarization component POL1, which is mainly p-polarized light, and the second liquid crystal cell 20 and the third liquid crystal cell 30 are configured to scatter (diffuse) the polarization component POL2, which is mainly s-polarized light.

[0069] In this embodiment, the liquid crystal lens LNS including four liquid crystal cells has been described, but the present embodiment is not limited to this. The liquid crystal lens LNS only needs to have at least one liquid crystal cell, and may have two or more liquid crystal cells.

[0070] Fig. 11 and Fig. 12 are diagrams showing the illuminance distribution of light emitted from the lighting elements, Fig. 11 and Fig. 12 showing the illuminance distribution in lighting elements IL2 and IL1, respectively. 11, the horizontal axis represents the distance from the center LG2c of the light guide plate LG2 in the first direction X, with the position of the center LG2c being set as 0, and the vertical axis represents illuminance. On the horizontal axis, the left end corresponds to the position of the side surface LG2s1, and the right end corresponds to the position of the side surface LG2s2. The closer to the side surface LG2s1, the closer to the light source element LSM2. Conversely, the closer to the side surface LG2s2, the farther from the light source element LSM2.

[0071] The illuminance of the lighting element IL1 is almost 0 (zero) from the side surface LG2s1 to the central portion LG1c. It rises sharply near the central portion LG2c, and the illuminance is approximately 5000 [lx] or more from the central portion LG2c to the side surface LG2s2. The maximum value is approximately 10000 [lx] at a position 20 mm away from the central portion LG2c toward the side surface LG2s2.

[0072] 12, the horizontal axis represents the distance from the center LG1c of the light guide plate LG1 in the first direction X, with the center LG1c being set as 0, and the vertical axis represents illuminance. On the horizontal axis, the left end corresponds to the position of the side surface LG1s1, and the right end corresponds to the position of the side surface LG1s2. The closer to the side surface LG1s1, the farther from the light source element LSM1. Conversely, the closer to the side surface LG1s1, the closer from the light source element LSM1.

[0073] The illuminance of the lighting element IL1 is almost 0 (zero) from the side surface LG1s2 to the center LG1c. It rises sharply near the center LG1c, and the illuminance is approximately 5000 [lx] or more from the center LG1c to the side surface LG1s1. The maximum value is approximately 10000 [lx] at a position 20 [mm] from the center LG1c toward the side surface LG1s1 (-20 [mm] position).

[0074] Fig. 13 and Fig. 14 are diagrams showing the relationship between the zenith angle of the lighting element and the normalized luminous intensity of the emitted light. Fig. 13 is a plot for lighting element IL2, and Fig. 14 is a plot for lighting element IL1. The relationship between the zenith angle θ [° (degrees)] and the normalized luminous intensity I [au] is also called the emission angle distribution.

[0075] 13 and 14, the apex angle on the horizontal axis indicates the angle of the emitted light in the first direction X or the angle of the emitted light in the second direction Y. The angle of the emitted light in the first direction X is the angle between the emitted light from the light source element and the YZ plane. The angle of the emitted light in the second direction Y is the angle between the emitted light from the light source element and the XZ plane. In ideal collimated light, the angle of the emitted light in the first direction X and the second direction Y is 0°, but in actual emitted light, there is a distribution of the emission angles.

[0076] 13 and 14, the output angle distribution Px in the first direction X is indicated by a solid line, and the output angle distribution Py in the second direction Y is indicated by a dotted line. As shown in Fig. 13, the illumination element IL2 has a maximum normalized luminous intensity I at an apex angle of 45° in the first direction X. In the second direction Y, the normalized luminous intensity I remains approximately constant even if the apex angle θ changes. This is because the light is not diffused by the liquid crystal lens LNS. 14, in the first direction X, the illumination element IL1 has a maximum normalized luminous intensity I at an apex angle of -45°. In the second direction Y, similar to the illumination element IL2, the normalized luminous intensity I is almost constant even if the angle θ changes.

[0077] Returning to Fig. 2, the lights LT1p and LT2p correspond to the emitted lights shown in Fig. 12 and Fig. 11, respectively. The angles R1p and R2p correspond to the apex angles in the first direction X shown in Fig. 14 and Fig. 13, respectively.

[0078] The lighting elements IL1 and IL2 cause the lights LT1 and LT2 to be emitted further outward as lights LT1p and LT2p, while the liquid crystal lens LNS in the on state causes the lights LT1 and LT2 to be emitted further inward as polarized lights LT1c and LT2c. In this way, by changing the emission angle, it is possible to irradiate light to a desired location.

[0079] 15, 16, 17, 18, 19, 20, 21, 22, and 23 are diagrams showing the relationship between the angle of the emitted light and the luminous intensity of the emitted light in the lighting device of this embodiment. FIG. 15, 16, and 17 show the relationship between the angle of the emitted light (also called the exit angle) and the luminous intensity in a configuration in which the liquid crystal lens LNS is not provided in the lighting device ILD. FIG. 18, 19, and 20 show the relationship between the angle of the emitted light and the luminous intensity of the lighting device ILD when the liquid crystal lens LNS is in the off state. FIG. 21, 22, and 23 show the relationship between the angle of the emitted light and the luminous intensity of the lighting device ILD when the liquid crystal lens LNS is in the on state. In FIG. 15 to FIG. 23, the angle [°] on the horizontal axis is the same as the apex angle θ in FIG. 13 and FIG. 14. The luminous intensity on the vertical axis is the same as the normalized luminous intensity in FIG. 13 and FIG. 14.

[0080] Fig. 15, Fig. 18, and Fig. 21 show the case where the lighting element IL1 is turned on, i.e., the light source element LSM1 is turned on. Fig. 16, Fig. 19, and Fig. 22 show the case where the lighting element IL2 is turned on, i.e., the light source element LSM2 is turned on. Fig. 17, Fig. 20, and Fig. 23 show the case where both the lighting elements IL1 and IL2 are turned on, i.e., both the light source elements LSM1 and LSM2 are turned on.

[0081] As shown in Fig. 15, in a configuration without the liquid crystal lens LNS, the luminous intensity of the emitted light from the lighting element IL1 is maximum when the emission angle is -45°. Similarly, as shown in Fig. 16, the luminous intensity of the emitted light from the lighting element IL2 is maximum when the emission angle is 45°. When both lighting elements IL1 and IL2 are turned on, the luminous intensity is maximum when the emission angles are -45° and 45°, as shown in Fig. 17.

[0082] When the liquid crystal lens LNS is provided but not turned on, the luminous intensity of the emitted light from the lighting element IL1 is maximum when the emission angle is −40°, as shown in FIG. 18. Similarly, the luminous intensity of the emitted light from the lighting element IL2 is maximum when the emission angle is 40°, as shown in FIG. 19. When both lighting elements IL1 and IL2 are turned on, the luminous intensity is maximum when the emission angles are −40° and 40°, as shown in FIG. 20. Since the emitted light is refracted when passing through the liquid crystal lens LNS, the emission angle is smaller than when the liquid crystal lens LNS is not provided. However, the effect on the emission angle is smaller than when the liquid crystal lens LNS is turned on (see below).

[0083] When the liquid crystal lens LNS is turned on, the luminous intensity of the emitted light from the lighting element IL1 is maximum when the emission angle is −20° as shown in Fig. 21. Similarly, the luminous intensity of the emitted light from the lighting element IL2 is maximum when the emission angle is 20° as shown in Fig. 22. When the liquid crystal lens LNS is in the on state, the exit angle of maximum luminous intensity is smaller than when it is in the off state. This is because, when the liquid crystal lens LNS is in the on state, the light that enters the liquid crystal lens LNS is diffused due to the influence of the refractive index distribution of the liquid crystal layer, as described above. This allows the exit light from the liquid crystal lens LNS to be emitted further inward.

[0084] When both lighting elements IL1 and IL2 are turned on, the luminous intensity is maximized when the emission angle is between -5° and 5°, as shown in Fig. 23. Since the emitted light from lighting elements IL1 and IL2 is combined, the luminous intensity is almost constant when the emission angle is between -5° and 5°. In this way, when the liquid crystal lens LNS is turned on and both lighting elements IL1 and IL2 are turned on, light with a constant luminous intensity can be obtained for the emission surface (illuminated surface).

[0085] 24, 25, 26, and 27 are diagrams showing an example of application of the lighting device of this embodiment. The vehicle VHC includes a driver's seat DRV, a passenger seat PRS, a windshield WSD, a shift lever SLV, a steering wheel WHL, a ceiling CEL, and a side mirror SMR. The lighting device ILD is provided on the ceiling CEL of the vehicle VHC.

[0086] 24 shows an example in which the illumination element IL2 of the illumination device ILD is turned on, i.e., only the light source element LSM2 is turned on, and the liquid crystal lens LNS is turned off. A spot light is emitted as illumination light ILT to the right and outside of the page. The illumination light ILT corresponds to light LT2p.

[0087] Fig. 25 shows an example in which both lighting elements IL1 and IL2 of the lighting device ILD are turned on, i.e., the light source elements LSM1 and LSM2 are turned on, and the liquid crystal lens LNS is turned off. Spot light is irradiated as illumination light ILT to both the left and right sides of the page, as well as to the outside. Illumination light ILT corresponds to light LT1p and LT2p. In the example shown in Fig. 25, spot light is irradiated to the outsides on the left and right, and the inside is dark because no light is irradiated thereto.

[0088] 26 shows an example in which the illumination element IL2 of the illumination device ILD is turned on, i.e., only the light source element LSM2 is turned on, and the liquid crystal lens LNS is turned on. Illumination light ILT is emitted to the right and inside of the drawing. The illumination light ILT corresponds to polarized light LT2c. FIG. 27 shows an example in which both lighting elements IL1 and IL2 of the lighting device ILD are turned on, i.e., the light source elements LSM1 and LSM2 are turned on, and the liquid crystal lens LNS is turned on. Illumination light ILT is irradiated to both the left and right sides of the page, as well as to the inside. Illumination light ILT corresponds to polarized light LT1c and LT2c. In the example shown in FIG. 27, the light irradiated to the left and right is biased toward the inside, so unlike FIG. 25, the entire area that the illumination light ILT reaches is illuminated. Also, as described in FIG. 23, such illumination light ILT has a uniform luminous intensity.

[0089] In the lighting device ILD of this embodiment, the light guide plates LG1 and LG2 are provided with convex portions TV1a and TV1b, and convex portions TV2a and TV2b on the side surfaces farther from the light source elements LSM1 and LSM2, respectively. A liquid crystal lens LNS capable of diffusing light is provided so as to overlap the lighting element IL1 including the light guide plate LG1 and the lighting element IL2 including the light guide plate LG2. The lighting elements IL1 and IL2 make it possible to obtain illumination light with a wide light distribution angle. The liquid crystal lens makes it possible to obtain illumination light with a narrow light distribution angle. By controlling the on / off of the light source elements LSM1 and LSM2 of the lighting elements IL1 and IL2, it is possible to irradiate light to either the left or right, or both. As described above, according to the present embodiment, it is possible to provide a lighting device capable of irradiating light onto a desired position.

[0090] In this disclosure, the light source elements LSM1 and LSM2 are referred to as the first light source element and the second light source element, respectively. The light guide plates LG1 and LG2 are referred to as the first light guide plate and the second light guide plate, respectively. The regions AR11, AR12, AR21, and AR22 are referred to as the first region, the second region, the third region, and the fourth region, respectively.

[0091] In this disclosure, the side surfaces LG1s1 and LG1s2 of the light guide plate LG1 and the side surfaces LG2s1 and LG2s2 of the light guide plate LG2 are referred to as the first side surface, the second side surface, the third side surface, and the fourth side surface, respectively. The main surfaces LG1a and LG1b of the light guide plate LG1 and the main surfaces LG2a and LG2b of the light guide plate LG2 are referred to as the first main surface, the second main surface, the third main surface, and the fourth main surface, respectively.

[0092] In this disclosure, the convex portions TV1a, TV1b, TV2a, and TV2b are referred to as a first convex portion, a second convex portion, a third convex portion, and a fourth convex portion, respectively. Among the sides of the scalene triangle that is the cross-sectional shape of the protrusion TV1a, sides E1a1, E1a2, and E1a3 are referred to as the first side, the second side, and the third side, respectively. Angle T1a1 formed by sides E1a1 and E1a2, angle T1a2 formed by sides E1a1 and E1a3, and angle T1a3 formed by sides E1a2 and E1a3 are referred to as the first angle, the second angle, and the third angle, respectively.

[0093] Among the sides of the scalene triangle that is the cross-sectional shape of the protrusion TV2a, sides E2a1, E2a2, and E2a3 are defined as the fourth, fifth, and sixth sides, respectively. Angle T2a1 formed by sides E2a1 and E2a2, angle T2a2 formed by sides E2a1 and E2a3, and angle T2a3 formed by sides E2a2 and E2a3 are defined as the fourth, fifth, and sixth angles, respectively.

[0094] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0095] AR11...area, AR12...area, AR21...area, AR22...area, IL1...illumination element, IL2...illumination element, ILD...illumination device, ILT...illumination light, LG1...light guide plate, LG1c...central portion, LG1s1...side portion, LG1s2...side portion, LG2...light guide plate, LG2c...central portion, LG2s1...side portion, LG2s2...side portion, LNS...liquid crystal lens, LSM1...light source element, LSM2...light source element, LT1...light, LT1c...polarized light, LT1p...light, LT2...light, LT2c...polarized light, LT2p...light, R1c...angle, R1p...angle, Rc...angle, Rp...angle, TV1a...convex portion, TV1b...convex portion, TV2a...convex portion, TV2b...convex portion.

Claims

1. A first lighting element including a first light source element and a first light guide plate having a first region and a second region; a second lighting element overlapping the first lighting element and including a second light source element and a second light guide plate having a third region and a fourth region; a liquid crystal cell overlapping the second lighting element; Equipped with The first light guide plate has a first side and a second side. The first light source element is disposed opposite the second side surface, the second region is located between the second side surface of the first light guide plate and the first region, the second light guide plate has a third side and a fourth side; The second light source element is disposed to face a third side surface of the second light guide plate, the fourth region is located between the fourth side surface of the second light guide plate and the third region, the fourth side surface is disposed closer to the second side surface than the first side surface, The first region of the first light guide plate is provided with a first convex portion on a first main surface and a second convex portion on a second main surface opposite to the first main surface, In the fourth region of the second light guide plate, a third convex portion is provided on a third main surface facing the second main surface, and a fourth convex portion is provided on a fourth main surface opposite to the third main surface, the first convex portion in the first region and the third convex portion in the fourth region partially overlap each other in a plan view, the liquid crystal cell includes a first substrate having a first electrode, a second substrate having a second electrode, and a liquid crystal layer provided between the first substrate and the second substrate; the first convex portion and the third convex portion each have a cross-sectional shape of a scalene triangle, The second convex portion and the fourth convex portion each have a cross-sectional shape of an isosceles triangle.

2. The lighting device according to claim 1 , wherein the first convex portion and the third convex portion are arranged in line symmetrical positions.

3. The lighting device according to claim 1 , wherein the first region and the third region overlap in a planar view, and the second region and the fourth region overlap in a planar view.

4. The lighting device according to claim 1 , wherein the second region and the third region do not overlap in a plan view.

5. the scalene triangle that is a cross-sectional shape of the first convex portion has a first side that is in contact with a first main surface of the first light guide plate, and a second side and a third side that extend from the first side, an angle formed by the first side and the second side is a first angle, an angle formed by the first side and the third side is a second angle, and an angle formed by the second side and the third side is a third angle; the scalene triangle that is the cross-sectional shape of each of the third protrusions has a fourth side that is in contact with a third main surface of the second light guide plate, and a fifth side and a sixth side that extend from the fourth side, the angle formed by the fourth side and the fifth side is a fourth angle, the angle formed by the fourth side and the sixth side is a fifth angle, and the angle formed by the fifth side and the sixth side is a sixth angle, The illumination device of claim 1 , wherein the first angle and the fourth angle are each 90°.

6. The first side, the second side, and the third side have different lengths, The lighting device according to claim 5 , wherein the fourth side, the fifth side, and the sixth side have different lengths.

7. The illumination device according to claim 1 , wherein the second convex portion and the fourth convex portion each have a cross-sectional shape of an equilateral triangle.

Images