Ceiling mounted lighting fixtures

Abstract

The purpose of the present embodiment is to provide a lighting device capable of irradiating a desired position with light.　In the present embodiment, a second light guiding plate of this lighting device has a fourth protruding part provided in a first region of a fifth principal surface facing a prism sheet, a plurality of fifth protruding parts provided in a second region of the fifth principal surface, and a sixth protruding part provided in a sixth principal surface on the reverse side from the fifth principal surface. The cross-sectional shape of the fourth protruding part and the cross-sectional shape of the fifth protruding part are each a scalene triangle, and the fourth protruding part and the fifth protruding part are disposed at line-symmetric positions in plan view.

Description

[Technical field]

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

[0002] Illumination devices that include light source elements on the end surfaces of a light guide plate have been developed, and in particular, illumination devices that control the direction of light emission have been developed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-223334 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 illumination element including a first light guide plate, a plurality of first light source elements provided on a first side surface of the first light guide plate, and a plurality of second light source elements provided on a second side surface opposite to the first side surface; a second illumination element including a second light guide plate, a plurality of third light source elements provided on a third side surface of the second light guide plate, and a plurality of fourth light source elements provided on a fourth side surface opposite to the third side surface; a prism sheet provided between the first lighting element and the second lighting element; Equipped with the first light guide plate has a plurality of first convex portions provided on a first main surface and a plurality of second convex portions provided on a second main surface opposite to the first main surface, the prism sheet has a third main surface facing the first light guide plate and a third convex portion provided on the third main surface facing the second light guide plate, the second light guide plate has a plurality of fourth convex portions provided in a first region of a fifth main surface facing the prism sheet, a plurality of fifth convex portions provided in a second region of the fifth main surface, and a plurality of sixth convex portions provided on a sixth main surface opposite the fifth main surface, a cross-sectional shape of the fourth convex portion and a cross-sectional shape of the fifth convex portion are scalene triangles, The fourth convex portion and the fifth convex portion are disposed at positions that are line-symmetrical in a plan view. 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 of the lighting device taken along line A1-A2 of FIG. [Diagram 3] FIG. 3 is a schematic enlarged cross-sectional view showing the shape of a convex portion of the lighting device. [Figure 4] FIG. 4 is a cross-sectional view of the lighting device taken along line B1-B2 of FIG. [Diagram 5] FIG. 5 is a diagram showing an example of application of the lighting device of this embodiment. [Figure 6] FIG. 6 is a diagram showing an example of application of the lighting device of this embodiment. [Figure 7] FIG. 7 is a diagram showing an example in which the lighting device of this embodiment is applied. [Figure 8] FIG. 8 is a diagram showing an example in which the lighting device of this embodiment is applied. 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. 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.

[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 a lighting device according to the present embodiment, and Fig. 2 is a cross-sectional view of the lighting device taken along line A1-A2 in Fig. 1. The illumination device ILD includes a reflector RFS, an illumination element IL1, a prism sheet PRS, and an illumination element IL2, which are laminated along the direction opposite to the third direction Z. Light emitted from the illumination device ILD is emitted downward.

[0013] The illumination element IL1 includes a light guide plate LG1 and a plurality of light source elements LSM11 and LSM12. The light source elements LSM11 are provided adjacent to a side surface LG1s1 of the light guide plate LG1. The light source elements LSM12 are provided adjacent to a side surface LG1s2 opposite to the side surface LG1s1. The side surfaces LG1s1 and LG1s2 are incident portions into which light from the light source elements LSM11 and LSM12 is incident, respectively. The center portion of the side of the light guide plate LG1 parallel to the first direction X is designated as LG1c.

[0014] The light guide plate LG1 has a main surface LG1a facing the reflector RFS and a main surface LG1b facing the prism sheet PRS. The main surface LG1b faces the main surface LG1a and is provided on the opposite side. The light guide plate LG1 has a plurality of protrusions TV1a on the main surface LG1a and a plurality of protrusions TV1b on the main surface LG1b.

[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 and each of the multiple protrusions TV1b has a triangular prism shape, and the cross-sectional shape is an isosceles triangle. The cross-sectional shape may be an equilateral triangle.

[0016] The prism sheet PRS has a main surface PRa facing the light guide plate LG1 and a main surface PRa facing the light guide plate LG2. The main surface PRa is provided on the opposite side to the main surface PRa. In Figures 1 and 2, a plurality of protrusions PRV are provided on the entire surface of the main surface PRa. Although not shown, a plurality of protrusions PRV may also be provided on the front surface of the main surface PRb.

[0017] The multiple protruding portions PRV 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 protruding portions PRV has a triangular prism shape, and the cross-sectional shape is a triangle. The cross-sectional shape is preferably an isosceles triangle, and may further be an equilateral triangle.

[0018] The illumination element IL2 includes a light guide plate LG2, a plurality of light source elements LSM21, and a plurality of light source elements LSM22. The light source elements LSM21 are provided adjacent to one side surface LG2s1 of the light guide plate LG2. The light source elements LSM22 are provided adjacent to a side surface LG2s2 opposite to the side surface LG2s1. The side surfaces LG2s1 and LG2s2 are incident portions into which light from the light source elements LSM21 and LSM22 is incident, respectively. The center portion of the side of the light guide plate LG2 parallel to the first direction X is designated as LG2c.

[0019] The light guide plate LG2 has a main surface LG2a facing the prism sheet PRS and a main surface LG2b facing the main surface LG2a and provided on the opposite side. The light guide plate LG2 has a plurality of protrusions TV2a1 and TV2a2 on the main surface LG2a, and a plurality of protrusions TV2b on the main surface LG2b.

[0020] In the main surface LG2a, a region from an end adjacent to the side surface LG2s1 to the central portion LG2c is defined as AR21, and a region from an end adjacent to the side surface LG2s2 to the central portion LG2c is defined as AR22. The multiple protrusions TV2a1 are provided in the region AR21, and the multiple protrusions TV2a2 are provided in the region AR22.

[0021] The multiple protrusions TV2a1 and TV2a2 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 TV2a1 and each of the multiple protrusions TV2a2 have a triangular prism shape.

[0022] Each of the multiple protrusions TV2a1 has a cross-sectional shape in the XZ plane that is a scalene triangle, with all sides having different lengths. Each of the multiple protrusions TV2a2 has a cross-sectional shape in the XZ plane that is a scalene triangle. The cross-sectional shapes of the protrusions TV2a1 and TV2a2 will be described in detail later.

[0023] The multiple protrusions TV2b each extend in a direction parallel to the first direction X and are arranged along a direction parallel to the second direction Y. Each of the multiple protrusions TV2b has a triangular prism shape, and the cross-sectional shape is an isosceles triangle. The cross-sectional shape may be an equilateral triangle.

[0024] 3 is a schematic enlarged cross-sectional view showing the shape of the convex portion of the lighting device. The cross-sectional shape of each of the convex portions TV2a1 and TV2a2 of the light guide plate LG2 in the XZ plane is a scalene triangle. Among the sides of the cross-sectional shape of the protrusion TV2a1, the side that contacts the main surface LG2a of the light guide plate LG2 is designated as E1a1. The protrusion TV2a1 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.

[0025] The lengths of sides E1a1, E1a2, and E1a3 are all different. It is preferable that the angle T1a1 is 90°. That is, it is preferable that the cross-sectional shape of the protrusion TV2a1 is a right-angled triangle. If the angle T1a1 is 90°, the light incident on the protrusion TV2a1 can be efficiently reflected, which is preferable. However, the angle T1a1 is not limited to this and may be an angle close to 90 degrees, for example, within a range of 80° to 90°.

[0026] Angle T1a2 is an acute angle, for example, 15°. Angle T1a3 is an acute angle, for example, 75°. 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 TV2a1 are Tg1 and Tp1, respectively. The pitch Tp1 is the sum of the length of side E1a1 and the interval Tg1. By setting the angles T1a1, T1a2, T1a3, and the pitch Tp1 to predetermined values ​​and changing the length of side E1a1 and the height Th1 of the convex portion TV2a1, the distribution of the emitted light can be controlled.

[0027] Among the sides of the cross-sectional shape of the protrusion TV2a2, the side that contacts the main surface LG2a of the light guide plate LG2 is designated as E2a1. The cross-sectional shape of the protrusion TV2a2 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.

[0028] The lengths of sides E2a1, E2a2, and E2a3 are all different. Like the angle T1a1 of the protrusion TV2a1, the angle T2a1 is preferably 90°. That is, the cross-sectional shape of the protrusion TV2a2 is preferably a right-angled triangle. If the angle T2a1 is 90°, the light incident on the protrusion 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°, for example, within a range of 80° to 90°.

[0029] 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 TV2a2 are Tg2 and Tp2, respectively. The pitch Tp2 is the sum of the length of side E2a1 and the interval Tg2. As with the convex portion TV2a1, the angle T1a1, the angle T2a2, the angle T2a3, and the pitch Tp2 are set to predetermined values, and the length of side E2a1 and the height Th2 of the convex portion TV2a2 can be changed to control the distribution of emitted light.

[0030] The cross-sectional shape of each of the protrusions TV2a1 and the cross-sectional shape of each of the protrusions TV2a2 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.

[0031] The angles T1a1 and T2a1, the angles T1a2 and T2a2, and the angles T1a3 and T2a3 are equal in size, respectively. The intervals Tg1 and Tg2, and the pitches Tp1 and Tp2, are equal to each other.

[0032] Fig. 4 is a cross-sectional view of the lighting device taken along line B1-B2 in Fig. 1. The cross-sectional shape in the XZ plane of each of the plurality of protruding portions TV1b of the light guide plate LG1 and each of the plurality of protruding portions TV2b of the light guide plate LG2 is an isosceles triangle. The cross-sectional shape may be an equilateral triangle.

[0033] Returning to FIG. 2, the light distribution angle of the emitted light will be described. In the illumination element IL1, light LT11 emitted from the light source element LSM11 enters the light guide plate LG1 from the side surface LG1s1. The light LT11 propagates through the light guide plate LG1 while being totally reflected along the first direction X. The reflection angle of the light LT11 is changed by the convex portion TV1a, and the light LT11 is emitted toward the prism sheet PRS.

[0034] The light LT11 incident on the principal surface PRa of the prism sheet PRS has its reflection angle further changed by the convex portion PRV, and is emitted from the principal surface PRb. The emitted light LT11 becomes more parallel to the third direction Z. In other words, it is emitted in a direction more perpendicular to the principal surface PRb. In this case, if the angle of the light LT11 with respect to the third direction Z is Rb1, the angle Rb1 is, for example, 10°. The light LT11 emitted from the principal surface PRb of the prism sheet PRS is incident on the illumination element IL2.

[0035] The light LT11 incident on the lighting element IL2 passes through the light guide plate LG2 and is emitted downward. The angle of the light LT11 emitted from the lighting element IL2 with respect to the third direction Z is defined as Rc1.

[0036] Light LT12 emitted from light source element LSM12 enters light guide plate LG1 from side surface LG1s2. The light LT12 propagates through light guide plate LG1 while being totally reflected in the direction opposite to first direction X. The reflection angle of light LT12 is changed by protrusions TV1a and TV1b, and the light LT12 is emitted toward prism sheet PRS.

[0037] The light LT12 incident on the principal surface PRa of the prism sheet PRS is further changed in reflection angle by the convex portion PRV, similar to the light LT11, and is emitted from the principal surface PRb. The emitted light LT1T becomes more parallel to the third direction Z. In other words, it is emitted in a direction more perpendicular to the principal surface PRb. In this case, if the angle of the light LT12 with respect to the third direction Z is Rb2, the angle Rb2 is, for example, 10°. The light LT12 emitted from the principal surface PRb of the prism sheet PRS is incident on the illumination element IL2. The sum of the angles Rb1 and Rb2 is the angle Rb.

[0038] The light LT12 incident on the lighting element IL2 passes through the light guide plate LG2 and is emitted downward. The angle of the light LT12 emitted from the lighting element IL2 with respect to the third direction Z is defined as Rc2. If the sum of the angles Rc1 and Rc2 is defined as angle Rc, the angle Rc is the light distribution angle of the light emitted from the lighting element IL1.

[0039] The lights LT11, LT12, LT21, and LT22 are collimated lights. In an 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. The convex portions TV1a, TV2a1, and TV2a2 contribute to the emission angle in the first direction X, and the convex portions TV1b and TV2b contribute to the emission angle in the second direction Y.

[0040] Here, assume that an illumination surface IF is formed on the XY plane by the light emitted from the illumination device ILD. The area illuminated by the illumination light emitted from the illumination device ILD actually has a three-dimensional spread. However, for ease of explanation, FIG. 2 describes an illumination surface IF that spreads on the XY plane.

[0041] An area AR1c on the irradiation surface IF that is irradiated by the emitted lights LT11 and LT12 is defined as the area AR1c. The area AR1c overlaps with a central portion LG1c of the light guide plate LG1 and a central portion LG2c of the light guide plate LG2 in a plan view.

[0042] In the illumination element IL2, light LT21 emitted from the light source element LSM21 enters the light guide plate LG2 from the side surface LG2s1. The light LT21 propagates through the light guide plate LG2 while being totally reflected along the first direction X. The reflection angle of the light LT21 is changed by the convex portions TV2a1, TV2a2, and TV2b, and the light LT21 is emitted obliquely with respect to the third direction Z.

[0043] Light LT22 emitted from light source element LSM22 enters light guide plate LG2 from side surface LG2s2. The light LT22 propagates through light guide plate LG2 while being totally reflected in the direction opposite to first direction X. The reflection angle of light LT22 is changed by protrusions TV2a1, TV2a2, and TV2b, and the light LT22 is emitted obliquely with respect to third direction Z.

[0044] The angles of the emitted light LT21 and LT22 with respect to the third direction Z are Rp1 and Rp2, respectively. If the sum of the angles Rp1 and Rp2 is angle Rp, the angle Rp is the light distribution angle of the emitted light from the lighting element IL2.

[0045] The area illuminated by light LT21 emitted obliquely from the light guide plate LG2 is denoted as AR2m, and the area illuminated by light LT22 is denoted as AR2h.

[0046] The angle Rp is larger than the angle Rc. The angles Rp1 and Rp2 are each, for example, 45°, i.e., the angle Rp is 90°. On the other hand, the angles Rc1 and Rc2 are each, for example, 15°, i.e., the angle Rc is 30°.

[0047] The angles Rb1 and Rb2 are, for example, 10° as described above. That is, the angle Rb is 20°. The light distribution angles of the light LT11 and LT12 increase when passing through the lighting element IL2. For example, the angle Rb1 of the light LT11 when it leaves the lighting element IL1 is 10°, but the angle Rc1 when it leaves the lighting element IL2 increases to 20°. However, the difference between the angles Rc1 and Rb1 is smaller than the difference between the angles Rc1 and Rp1. The difference between the angles Rc2 and Rb2 is smaller than the difference between the angles Rc2 and Rp2. Therefore, even if the light distribution angle increases when passing through the lighting element IL2, the effect is considered to be small.

[0048] On the illumination plane IF, a non-illuminated area VCh exists between the areas AR1c and AR2h. A non-illuminated area VCm exists between the areas AR1c and AR2m. However, this embodiment is not limited to this, and angles Rc and Rp may be determined so that areas VCh and VCm do not exist.

[0049] 5, 6, 7, and 8 are diagrams showing an example of application of the lighting device of this embodiment. A room RM has a door DR, a desk DK, chairs CR1 and CR2, an object OBJ, and a lighting device ILD provided on a ceiling CIL. The object OBJ is provided near the center of the room RM and may be, for example, a television or a painting.

[0050] 5 shows an example in which both lighting elements IL1 and IL2 of the lighting device ILD are turned on, i.e., all light source elements LSM11, LSM12, LSM21, and LSM22 are turned on. Illumination light ILT is emitted to both the left and right of the page and both the inside and outside. Illumination light ILT corresponds to light LT11, LT12, LT21, and LT22. For example, such illumination may be performed when the entire room RM is to be brightly illuminated.

[0051] 6 shows an example in which only the illumination element IL2 of the illumination device ILD is turned on, i.e., the light source elements LSM21 and LSM22 are turned on. The illumination element IL1 is turned off, i.e., the light source elements LSM11 and LSM12 are turned off. The illumination light ILT is a spot light that is irradiated only to the outside and to the left and right of the page. The illumination light ILT corresponds to the lights LT21 and LT22. For example, such illumination can be performed when the center of the room RM is not illuminated, but the room RM is not in a dark state.

[0052] FIG. 7 shows an example in which only the illumination element IL1 of the illumination device ILD is in the on state, i.e., the light source elements LSM11 and LSM12 are turned on. The illumination element IL2 is in the off state, i.e., the light source elements LSM21 and LSM22 are turned off. The illumination light ILT is a spot light that is irradiated only on the inside of both the left and right sides of the paper. The illumination light ILT corresponds to the lights LT11 and LT12. For example, this type of illumination can be performed when illuminating the center of the room RM, opposite to FIG. 6. More specifically, it is possible to illuminate the desk DK and the object OBJ that are placed near the center of the room RM.

[0053] FIG. 8 shows an example in which only light source element LSM22 of lighting element IL2 of lighting device ILD is turned on. Light source elements LSM11 and LSM12 of lighting element IL1 and light source element LSM21 of lighting element IL2 are turned off. Illumination light ILT is a spot light that is irradiated only to the left side of the paper and to the outside. Illumination light ILT corresponds to light LT22. For example, such illumination may be performed when illuminating one side of a room RM (the left side of the paper). More specifically, it is possible to illuminate a door DR provided on one side of the room RM.

[0054] The lighting device of this embodiment can illuminate an area near the center of the irradiation surface by turning on the lighting element IL1. It can illuminate an area outside the irradiation surface by turning on the lighting element IL2. It is also possible to illuminate either the left or right area or both areas by adjusting the on / off state of the light source elements provided at the left and right ends. As described above, according to the present embodiment, it is possible to provide a lighting device capable of irradiating light onto a desired position.

[0055] In the present disclosure, the light guide plates LG1 and LG2 are also referred to as the first light guide plate and the second light guide plate, respectively. The side surfaces LG1s1, LG1s2, LG2s1, and LG2s2 are also 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, LG1b, PRa, PRb, LG2a, and LG2b are also referred to as the first main surface, the second main surface, the third main surface, the fourth main surface, the fifth main surface, and the sixth main surface, respectively. The regions AR21 and AR22 of the light guide plate LG2 are also referred to as the first region and the second region, respectively.

[0056] The convex portions TV1a, TV1b, PRV, TV2a1, TV2a2, and TV2b are also referred to as a first convex portion, a second convex portion, a third convex portion, a fourth convex portion, a fifth convex portion, and a sixth convex portion, respectively.

[0057] Among the sides of the scalene triangle that is the cross-sectional shape of the protrusion TV2a1, the sides E1a1, E1a2, and E1a3 are called the first side, the second side, and the third side, respectively. The angle T1a1 formed by the sides E1a1 and E1a2, the angle T1a2 formed by the sides E1a1 and E1a3, and the angle T1a3 formed by the sides E1a2 and E1a3 are called the first angle, the second angle, and the third angle, respectively.

[0058] Among the sides of the scalene triangle that is the cross-sectional shape of the protrusion TV2a2, 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.

[0059] 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]

[0060] AR1c...area, AR21...area, AR22...area, IL1...illumination element, IL2...illumination element, ILD...illumination device, ILT...illumination light, LG1...light guide plate, LG1a...main surface, LG1b...main surface, LG1c...central portion, LG1s1...side surface, LG1s2...side surface, LG2...light guide plate, LG2a...main surface, LG2b...main surface, LG2c...central portion, LG2s1...side surface, LG 2s2...side, LSM11...light source element, LSM12...light source element, LSM21...light source element, LSM22...light source element, LT11...light, LT12...light, LT21...light, LT22...light, Rc...angle, Rc1...angle, Rc2...angle, Rp...angle, Rp1...angle, TV1a...convex portion, TV1b...convex portion, TV2a1...convex portion, TV2a2...convex portion, TV2b...convex portion.

Claims

1. a first lighting element including a first light guide plate, a plurality of first light source elements provided on a first side surface of the first light guide plate, and a plurality of second light source elements provided on a second side surface opposite to the first side surface; a second lighting element including a second light guide plate, a plurality of third light source elements provided on a third side surface of the second light guide plate, and a plurality of fourth light source elements provided on a fourth side surface opposite to the third side surface; a prism sheet provided between the first lighting element and the second lighting element; Equipped with The first light source element and the second light source element emit light to the first light guide plate along a first direction, the third light source element and the fourth light source element emit light to the second light guide plate along the first direction; the first light guide plate has a plurality of first convex portions provided on a first main surface and a plurality of second convex portions provided on a second main surface opposite to the first main surface, The plurality of first protrusions are arranged along the first direction and extend along a second direction intersecting the first direction, The second protrusions are arranged along the second direction and extend along the first direction, the prism sheet has a third main surface facing the first light guide plate, and a fourth main surface facing the second light guide plate; the third protrusions are arranged along the first direction and extend along the second direction; the second light guide plate has a plurality of fourth convex portions provided in a first region of a fifth main surface facing the prism sheet, a plurality of fifth convex portions provided in a second region of the fifth main surface, and a plurality of sixth convex portions provided on a sixth main surface opposite to the fifth main surface, the plurality of fourth protrusions are arranged along the first direction and extend along the second direction; The plurality of fifth protrusions are arranged along the first direction and extend along the second direction, The sixth protrusions are arranged along the second direction and extend along the first direction, a cross-sectional shape of the fourth convex portion and a cross-sectional shape of the fifth convex portion are scalene triangles, A lighting device for installation on a ceiling, wherein the fourth convex portion and the fifth convex portion are arranged at positions that are line-symmetrical in a plan view.

2. the scalene triangle that is a cross-sectional shape of the fourth protrusion has a first side that is in contact with the fifth main surface, 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 the fifth protrusion has a fourth side that is in contact with the fifth main surface, 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 lighting device for ceiling installation according to claim 1 , wherein the first angle and the fourth angle are 90°.

3. The first side, the second side, and the third side have different lengths, The lighting device for ceiling installation according to claim 2 , wherein the fourth side, the fifth side, and the sixth side have different lengths.

4. The lighting device for ceiling installation according to claim 1 , wherein the first convex portions, the second convex portions, the third convex portions, and the sixth convex portions each have a cross-sectional shape of an isosceles triangle.

5. The lighting device for ceiling installation according to claim 4 , wherein the first convex portions, the second convex portions, the third convex portions, and the sixth convex portions each have a cross-sectional shape of an equilateral triangle.

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