JP2014096348A - Lighting device - Google Patents

Abstract

Provided is a lighting device capable of suppressing light leakage from the inside of a light guide plate and achieving high efficiency.
A light guide plate includes: a light incident portion on which light from an LED element is incident; and light bending that causes light incident from the light incident portion to bend in a light guide direction that intersects an optical axis direction of the LED element. And a light emitting part 23 that emits the light bent by the light bending part 22. The light bending portion 22 is formed with a groove portion 22a having a V shape in the light guide direction as viewed from the light guide direction.
[Selection] Figure 2

Description

  The present invention relates to an illumination device that guides light from a light source using a light guide plate.

  2. Description of the Related Art Conventionally, an illumination device using a light guide plate includes a light source such as an LED element in a bottomed cylindrical housing and a light guide plate facing the light source, and light is emitted from a light emitting portion of the light guide plate. As a result, light comes on (see, for example, Patent Document 1). As such an illuminating device, a device in which a light source such as an LED element is mounted on the housing side, and a light path of light incident on the light guide plate is bent and guided in the light guide direction is known. Specifically, by making the outer edge portion of the light guide plate have a curved shape, it is easy to totally reflect light.

JP 2004-319164 A

  By the way, in the illuminating device as described above, the outer edge portion of the light guide plate is simply curved, and the light incident on the light guide plate is bent (totally reflected) at the outer edge portion of the curved shape. However, if it is assumed that the refractive index of the light guide plate is around 1.5, leakage light is generated unless the light guide plate is bent at a radius of curvature more than five times the thickness of the light guide plate, leaving room for improvement in terms of efficiency. Yes.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an illuminating device that can suppress the leakage of light from the light guide plate and achieve high efficiency.

  In order to solve the above-described problem, the lighting device includes a light source and a light guide plate that guides light emitted from the light source, and the light guide plate receives light from the light source. A light incident portion, a light bending portion that bends at least a part of light incident from the light incident portion in a light guide direction intersecting an optical axis direction of the light source, and light emitted by the light bending portion is emitted. The light bending portion is characterized in that a groove portion having a V shape is formed along the light guide direction when viewed from the light guide direction.

Moreover, the said structure WHEREIN: It is preferable that the said groove part is formed so that the vertex angle may be 80-110 degree | times.
Moreover, the said structure WHEREIN: It is preferable that the said groove part is formed so that the center side of the said light-guide plate may become shallow.

In the above configuration, it is preferable that the light source includes a plurality of LED elements, and a plurality of the groove portions are formed in the LED element arranging direction.
Moreover, the said structure WHEREIN: It is preferable that the said groove part is formed in the position corresponding to the said LED element.

Moreover, the said structure WHEREIN: As for the said light guide plate, it is preferable that the groove part of the said light bending part is formed over the whole outer edge part.
Further, in the above configuration, the light guide plate includes the light bending portion formed by a plurality of the groove portions, and the remaining portions of the light guide plate that are formed between the groove portions and bent in the light guide direction to guide light. It is preferable to include a partial light bending portion that leaks light to the outside.

In the above configuration, it is preferable that a diffusion member is provided at least at a position facing the partial light bending portion.
Moreover, the said structure WHEREIN: It is preferable that the said groove part has a diffusibility, and is comprised in the aspect which a part of light leaks outside the said light-guide plate.

In the above configuration, it is preferable that a diffusing member is provided at a position facing the groove.
In the above-described configuration, it is preferable to include a substrate on which the light source is provided and a housing for fixing the light guide plate, and a diffusion transmission plate provided so as to cover an opening of the housing.

  According to the present invention, the illuminating device can be highly efficient by suppressing light leakage from the light guide plate.

It is a perspective view of the illuminating device in 1st Embodiment. It is a perspective view which shows a part of light guide plate of the illuminating device same as the above. It is a top view for demonstrating the light bending part of the light-guide plate in the same as the above. (A) is a schematic diagram schematically showing light when a light guide plate having a groove portion is used, and (b) schematically showing light when a light guide plate having a groove portion is used. It is a schematic diagram. It is explanatory drawing for demonstrating the bending of the light in a groove part. It is explanatory drawing for demonstrating the bending of the light in a groove part. It is explanatory drawing for demonstrating the bending of the light in a groove part. (A) (b) is explanatory drawing for demonstrating the vertex angle of a groove part. (A) (b) is explanatory drawing for demonstrating the apex angle of the groove part of a comparative example. It is a perspective view for demonstrating an example of the groove part at the time of making a light-guide plate into a bottomed cylindrical shape. It is a perspective view for demonstrating the groove part of the light-guide plate of the illuminating device in 2nd Embodiment. It is a top view for demonstrating the groove part formation position in a groove part same as the above. It is explanatory drawing for demonstrating a groove part formation position. It is a perspective view which shows a part of light guide plate of the illuminating device in another example. It is a perspective view which shows a part of light-guide plate of the illuminating device in another example. It is explanatory drawing for demonstrating the housing | casing and cover part of the illuminating device in another example. It is explanatory drawing for demonstrating the housing | casing and cover part of the illuminating device in another example. It is explanatory drawing for demonstrating the housing | casing and cover part of the illuminating device in another example. It is explanatory drawing for demonstrating the housing | casing and cover part of the illuminating device in another example.

(First embodiment)
Hereinafter, 1st Embodiment of an illuminating device is described according to drawing.
As shown in FIG. 1, the illuminating device 10 of this embodiment is equipped with the LED element 12 as a light source, and the substantially disc shaped light-guide plate 13 on the substantially disc shaped base part 11. As shown in FIG.

  As shown in FIG. 1, a plurality (16 in the case of this embodiment) of LED elements 12 are provided at equal intervals in the circumferential direction on the lower surface 11 a on the outer edge side of the base portion 11. The LED element 12 is disposed opposite to the light guide plate 13 on the light emitting side opposite to the base portion 11.

As shown in FIGS. 1 to 3, the light guide plate 13 has a bottomed cylindrical shape, and includes a light incident part 21, a light bending part 22, and a light emitting part 23.
As shown in FIG. 3, the light incident portion 21 of the light guide plate 13 is an end portion (end surface) on the opening side of the disc-shaped light guide plate 13, and this end portion is arranged to face the LED element 12 to be an LED element. Light emitted from 12 is made incident.

  As shown in FIGS. 2 and 3, the light bending portion 22 bends the light incident on the light incident portion 21 (changes the light traveling direction) and is substantially orthogonal to the optical axis L <b> 1 of the LED element 12. In this structure, the light is guided in the light guide direction L2. Further, as shown in FIG. 2, the light bending portion 22 has a V-shaped groove portion 22a formed along the light guide direction L2 when viewed from the light guide direction L2. A plurality of the groove portions 22a are formed in the arrangement direction (circumferential direction) of the LED elements 12. The groove 22a is configured so that the two flat surfaces 22b intersect each other in a V shape, and the apex angle θ1 is in the range of approximately 80 to 110 degrees as shown in FIGS. 8 (a) and 8 (b). As shown in 9 (a) and 9 (b), light leakage occurs when the apex angle θ1 is in a wider range. The apex angle θ1 of the groove 22a is more preferably 90 degrees. Incidentally, the optical axis L1 shown in FIG. 3 shows the rough direction of the light of the LED element 12.

  The light emitting portion 23 is an exit surface from which light guided by being bent by approximately 90 degrees at the light bending portion 22 is emitted. The back surface 24 of the light emitting portion 23 is subjected to surface treatment for diffusing light by forming diffusible printing, fine grooves, and the like. For this reason, a part of light is diffused and emitted from the light emitting portion 23 by the back surface 24. Incidentally, by adjusting the density of the surface treatment of the back surface 24 according to the intensity of light guided in each part of the light guide plate 13, it is possible to make the entire light emitting part 23 emit light uniformly.

Next, the effect | action of the light-guide plate 13 of the illuminating device 10 of this embodiment is demonstrated.
Here, since the light guide plate 13 is made of a transparent material such as a resin such as acrylic, polycarbonate, or polystyrene, or glass, the refractive index is approximately 1.4 to 1.8. At this time, the critical angle θ2 in which light is guided without being emitted from the light guide plate 13 into the air (refractive index≈1) is expressed by the following equation.

θ2 = Arcsin (1 / n)
n: Refractive index From the above formula, the critical angle θ2 is 33 to 45.6 degrees. For this reason, as shown in FIG. 3, when the angles of the normal lines HL1 to HL3 of the light guide plate 13 and the light rays A to C are smaller than the critical angle θ2, light leaks from the light guide plate 13. For example, in an illuminating device that requires a large luminous flux, the individual LED elements 12 become larger to increase the luminous flux as shown in FIG. 3, while the light guide plate 13 is designed to be as thin as possible in order to reduce the weight. Therefore, the thickness of the light guide plate 13 and the size of the LED element 12 are close to each other as shown in FIG. Therefore, light such as the light rays A to C shown in FIG. 3 cannot be bent by the light bending portion 22 that does not have the groove portion 22a and becomes leaked light.

  Therefore, when the V-shaped groove portion 22a is formed on the outer surface of the light bending portion 22, the light leaked without being totally reflected as shown in FIG. 4 (a), as shown in FIG. 4 (b). Total reflection is possible. Here, the behavior of light when light inside the light guide plate 13 enters the V-shaped groove 22a will be described with reference to FIGS. In order to facilitate understanding of the behavior of light, a description will be given of a structure in which a plurality of V-shaped groove portions 22a are formed in the planar direction of the light guide X having a shape different from that of the light guide plate 13. As described above, if there is no V-shaped groove 22a, light leaks from the light guide X in the direction indicated by the broken line with an arrow in FIG. However, since the V-shaped groove 22a is provided, the angle formed between the normal line of the light guide X and the incident light beam is increased, the critical angle θ2 (see FIG. 8) is apparently reduced, and the light is totally reflected. When the apex angle θ1 of the V-shaped groove 22a of the light guide plate 13 and this example is 90 degrees, the angle formed by the flat surface 22b of the groove 22a and the optical axis of the LED element 12 is approximately 45 degrees. Further, since the apex angle θ1 of the groove 22a is 90 degrees, the direction of light is hardly disturbed as shown in FIGS.

Next, the effect of this embodiment will be described.
(1) The light guide plate 13 bends the light incident part 21 where the light of the LED element 12 is incident and the light incident direction L2 intersecting the optical axis L1 of the LED element 12 with the light incident from the light incident part 21. The light bending part 22 and the light emission part 23 which inject | emits the light bent by the light bending part 22 are provided. The light bending portion 22 is formed with a groove portion 22a having a V shape when viewed from the light guide direction L2 along the light guide direction L2. Since the light is totally reflected by the groove portion 22a and is easily collected on the light emitting portion 23 side at the center of the light guide plate 13, leakage of light from the light guide plate 13 can be suppressed and high efficiency can be achieved.

  (2) Since the groove portion 22a is formed such that the apex angle θ1 is 80 to 110 degrees, it is easy to totally reflect light in the groove portion 22a, and thus light leakage can be suppressed. Further, by setting the apex angle θ1 to approximately 90 degrees, it is possible to suppress the disturbance of the light direction.

(3) Since a plurality of groove portions 22a are formed, it is possible to correspond to a wide range of light emitted from the LED element 12, and light leakage can be further suppressed.
(Second Embodiment)
Next, the illuminating device of 2nd Embodiment is demonstrated.

  In the illumination device of the present embodiment, the shape of the light guide plate is different from that of the illumination device of the first embodiment. Therefore, the difference is mainly described, and the same member numbers are used for the same configurations as in the first embodiment. A part or all of the explanation is omitted.

  As shown in FIG. 11, the light guide plate 31 of the present embodiment includes a light incident portion 21, a light bending portion 22, and a light emitting portion 23, similarly to the light guide plate 13 of the first embodiment. In the present embodiment, in this embodiment, the light guide plate 31 is configured such that the light incident portion 21 and the back surface 24 (see FIG. 3) of the light emitting portion 23 are on the same plane.

  As shown in FIG. 11, the light bending portion 22 has a V-shaped groove portion 32. The groove portion 32 is formed so that the depth thereof becomes shallower toward the light emitting portion 23 side of the light guide plate 31. Further, the groove 32 is formed up to the position where total reflection starts in the light bent portion 22 even without the groove 32. Here, the “position where total reflection starts even without the groove 32” is defined. However, it also differs depending on the shape of the light bending portion 22 and the refractive index of the light guide plate 31 (light guide). As shown in FIG. 12, with respect to the perpendicular PL1 of the light emitting portion end point on the center side of the light guide plate 31 of the LED element 12, among the light emitted from the end point, for example, to the light guide plate 31 side of the outermost optical path D The inclination angle is θ3. When the inclination angle of the tangent TL of the outer surface of the light guide plate 31 at the intersection IP of the light beam D1 reflected by the light bending portion 22 in the optical path D and the outer surface of the light guide plate 31 is θ4, θ3 + θ4 is greater than the critical angle of the light guide plate 31. If it is larger, total reflection starts. For this reason, the relationship is as follows.

θ3 + θ4 <Arcsin (1 / n)
n: Refractive index of the light guide plate That is, the light is totally reflected even if there is no V-shaped groove 32 on the center side of the light guide plate 31 from the intersection IP satisfying the above formula. For this reason, it is possible to suppress light leakage by forming the groove 32 up to the intersection point IP.

Next, the operation of the illumination device of this embodiment will be described.
The light guide plate 31 of the lighting device of the present embodiment is formed such that the depth of the groove portion 32 becomes shallower toward the center of the light guide plate 31. Here, when the depth of the V-shaped groove is constant, the height changes abruptly at the end of the V-shaped groove. In such a place, the behavior of the light being guided changes abruptly, so that luminance unevenness occurs at the boundary (groove end). However, as described above, the groove portion 32 of the present embodiment is formed so that the depth becomes shallower toward the center side of the light guide plate 31, so that the change in shape at the end of the groove portion 32 is suppressed and the occurrence of luminance unevenness is suppressed. Can do.

As described above, the lighting device of the present embodiment has the following effects in addition to the effects (1) and (2) of the first embodiment.
(3) Since the groove portion 32 is formed so as to be shallower toward the center side of the light guide plate 31, it is possible to suppress a sudden change in the cross-sectional shape at the boundary portion of the groove portion 32 on the center side of the light guide plate 31. Thereby, since it is possible to suppress a sudden change in the behavior of light at the boundary portion, it is possible to suppress the occurrence of luminance unevenness.

In addition, you may change embodiment of this invention as follows.
In each of the above embodiments, although not particularly mentioned, it is preferable that a plurality of the groove portions are formed in the LED element arrangement direction. In particular, it is preferably formed at a position corresponding to the LED element 12. At this time, as shown in FIG. 13, the groove portions 22a and 32 are formed only in a portion where light leakage occurs if the groove portions 22a and 32 are not provided in the arrangement direction of the LED element 12 (left and right direction on the paper surface). Specifically, assuming that the range in which light leakage occurs without the groove portions 22a and 32 in the arrangement direction of the LED element 12 is α and the refraction angle of the light guide plates 13 and 31 is n, α <Arcsin (1 / n) The groove portions 22a and 32 are formed in a range that satisfies the above relationship.

  In each of the above embodiments, the groove portions 22a and 32 of the light bending portion 22 are formed in a part of the outer edge portion of the light guide plates 13 and 31, but this is not a limitation, and the light guide plate 13 is not limited to this. You may form the groove part 22a over the whole outer edge part.

  In each of the above embodiments, the light guide plate 13 is configured to have a disk shape (a circular shape when viewed from the direction orthogonal to the light emitting portion 23 of the light guide plate 13). It is good also as polygonal shapes, such as. In short, any shape can be applied as long as the groove 22a is formed in the light bending portion 22 as shown in FIG. 10 and the light is guided in the light guide direction L2 from the optical axis L1 of the LED element 12. It is.

  In each of the above embodiments, although not particularly mentioned, a diffusion plate or a diffusion sheet may be installed at a position facing the light emitting portion 23 of the light guide plate 13 in order to make the light more uniform. Further, a reflecting plate having a high reflectance may be installed on the base portion 11 opposite to the light emitting portion 23 of the light guide plate 13, or white coating or mirror surface treatment may be applied to the base portion 11 itself.

  In each of the above embodiments, the LED element 12 is used as a light source, but the light source is not limited to this. For example, instead of the LED element 12, a straight tube type cold cathode fluorescent lamp (CCFL) or the like may be employed as the light source. Moreover, you may use an organic EL element (OLED) as a light source.

  In each of the above embodiments, the two flat surfaces 22b are intersected to form the V-shaped groove 22a. However, the present invention is not limited to this. For example, the curved surface may be crossed instead of the flat surface 22b to form a V-shaped groove.

  Although not specifically mentioned in each of the above embodiments, the LED element 12 and the light guide plate 13 as the light source may adopt a configuration provided in an accommodation space configured by a housing and a cover portion. The following combinations of the case and the cover are conceivable. However, it may be other than the configuration shown below.

(Configuration S1)
As shown in FIG. 16, the housing 40 of the illumination device 10 is formed in a substantially flat plate shape. One planar portion 41 of the housing 40 is provided with a reflecting member 42 at the center thereof, and a substrate 43 is fixed to the outer edge side with screws or the like. An LED element 12 as a light source is disposed on the substrate 43. A light guide plate 45 is provided at a position facing the LED element 12, and the light guide plate 45 is fixed in the housing 40 by a support member (not shown).

  The housing 40 includes a cover portion 46 so as to cover one flat surface portion 41 of the housing 40. Since the cover portion 46 has a bottomed cylindrical shape, the bottom portion 46a of the cover portion 46 and the flat portion 41 of the housing 40 are separated from each other, that is, an accommodation space in which the substrate 43, the light guide plate 45, and the like can be accommodated. Have. The cover 46 is configured to transmit and diffuse light.

  The light guide plate 45 includes a light incident part 21, a light bending part 22, and a light emitting part 23, for example, as in the first embodiment. The light bending portion 22 is formed with a groove portion 22a having a V shape when viewed from the light guide direction L2 along the light guide direction L2. Further, as shown in FIG. 15, the light guide plate 45 may employ a configuration including a curved surface portion 45a as a partial light bending portion between the groove portions 22a. The curved surface portion 45a preferably has a curved surface shape and is configured such that a part of the light passing through the light guide plate 45 is totally reflected and the remaining light leaks. With such a configuration, the light R2, R3 is emitted from the outer edge portion 46b of the bottom portion 46a of the transparent cover portion 46 or the side wall portion 46c formed to extend from the end portion of the outer edge portion 46b to the outside of the cover portion 46. Can be emitted. Further, the light R1 totally reflected by the curved surface portion 45a is emitted from the center of the bottom portion 46a of the cover portion 46.

  As shown in FIG. 16, a light diffusion sheet 47 as a diffusion member may be provided between the cover portion 46 and the light guide plate 45. For example, the light diffusion sheet 47 can diffuse light emitted from the curved surface portion 45a (leaked light) by providing the light diffusion sheet 47 at a position facing the curved surface portion 45a as the partial light bending portion provided between the groove portions 22a. The occurrence of uneven brightness can be suppressed.

(Configuration S2)
As shown in FIG. 18, the housing 50 of the lighting device 10 is formed in a substantially bottomed cylindrical shape. A substrate 43 is fixed to the bottom 50a of the housing 50 with screws or the like. An LED element 12 as a light source is disposed on the substrate 43. A light guide plate 45 is provided at a position facing the LED element 12, and the light guide plate 45 is fixed in the housing 50 by a support member (not shown).

  The housing 50 has an opening 50 b wider than the light guide plate 45. The housing 50 includes a cover portion 52 that closes the opening 50b in the opening 50b. The cover 52 has a flat plate shape and is configured to transmit and diffuse light.

  The light guide plate 45 includes a light incident part 21, a light bending part 22, and a light emitting part 23, for example, as in the first embodiment. The light bending portion 22 is formed with a groove portion 22a having a V shape when viewed from the light guide direction L2 along the light guide direction L2. Further, as shown in FIG. 15, the light guide plate 45 may employ a configuration including a curved surface portion 45a as a partial light bending portion between the groove portions 22a. The curved surface portion 45a preferably has a curved surface shape and is configured such that a part of the light passing through the light guide plate 45 is totally reflected and the remaining light leaks. With such a configuration, it is possible to emit the light R2 from the outer edge portion 52b of the bottom portion 52a of the cover portion 46 having transparency to the outside of the cover portion 46. Further, the light R1 totally reflected by the curved surface portion 45a is emitted from the center of the bottom portion 46a of the cover portion 46.

(Configuration S3)
As shown in FIG. 19, the housing 60 of the lighting device 10 is formed in a substantially bottomed cylindrical shape. A substrate 43 is fixed to the bottom 60a of the housing 60 with screws or the like. An LED element 12 as a light source is disposed on the substrate 43. A light guide plate 45 is provided at a position facing the LED element 12, and the light guide plate 45 is fixed in the housing 60 by a support member (not shown).

The housing 60 includes a closing plate 60 c having a hole 60 b on one surface side, and the hole 60 b (opening) is configured to be an opening narrower than the light guide plate 45.
The housing 60 includes a cover portion 62 that closes the hole 60b in the hole 60b. The cover part 62 has a flat plate shape and is configured to transmit and diffuse light.

  In such a configuration, it is preferable to form the groove 22a over the entire outer edge of the light guide plate 13 as shown in FIG. At this time, it is preferable that the groove portion 22 a is continuously formed over the entire outer edge portion of the light guide plate 13. Thus, since the groove portion 22a is continuously formed over the entire outer edge portion of the light guide plate 13, the light is easily collected on the light emitting portion 23 side at the substantially central side of the light guide plate 13, so High efficiency can be achieved by suppressing light leakage.

  Incidentally, although the curved surface portion 45a is provided between the groove portions 22a in the configuration S1 and the configuration S2, a configuration in which the curved surface portion 45a is omitted may be employed. In this case, a configuration may be adopted in which a part of light is leaked from the groove 22a to a necessary place by performing diffusion treatment on the surface of the V-shaped groove 22a. The diffusion treatment can be realized by chemical roughening, sand blasting, or micro uneven processing on the mold. Incidentally, it goes without saying that the light that is bent by forming the groove 22a and guided to the center side (light guide direction) of the light guide plate 45 is larger than before the groove 22a is formed.

In the configuration S1, the reflection member 42 is provided. However, as shown in FIG. 17, a configuration in which the reflection member 42 is omitted may be adopted.
In the configuration S1, the light diffusion sheet 47 is provided. However, as shown in FIG. 17, a configuration in which the light diffusion sheet 47 is omitted may be adopted.

  -Each above-mentioned embodiment and each above-mentioned modification may be combined suitably.

  DESCRIPTION OF SYMBOLS 10 ... Illuminating device, 12 ... LED element as a light source, 13, 31, 45 ... Light guide plate, 21 ... Light incident part, 22 ... Light bending part, 22a, 32 ... Groove part, 23 ... Light emitting part, 40, 50, 60 ... Case, 43 ... Substrate, 45a ... Curved surface part (partial light bending part), 46,52,62 ... Cover part (diffuse transmission plate), 46b, 52b ... Outer edge part, 47 ... Diffusion sheet (diffusion member), 50b: opening, θ1: apex angle, L2: light guide direction, R1, R2, R3: light.

Claims (11)

An illumination device having a light source and a light guide plate that guides light emitted from the light source,
The light guide plate includes a light incident portion on which light from the light source is incident, and a light bending portion that bends at least part of the light incident from the light incident portion in a light guide direction that intersects the optical axis direction of the light source. And a light emitting portion that emits light bent by the light bending portion, and the light bending portion has a V-shaped groove portion along the light guide direction when viewed from the light guide direction. An illumination device characterized by being formed. The lighting device according to claim 1.
The groove portion is formed so that an apex angle thereof is 80 to 110 degrees. The lighting device according to claim 1 or 2,
The illuminating device is characterized in that the groove portion is formed so as to be shallower toward a center side of the light guide plate. In the illuminating device as described in any one of Claims 1-3,
The light source is configured by arranging a plurality of LED elements,
A plurality of the groove portions are formed in the arrangement direction of the LED elements. The lighting device according to claim 4.
The groove is formed at a position corresponding to the LED element. The lighting device according to claim 4.
In the light guide plate, the groove portion of the light bending portion is formed over the entire outer edge portion. In the illuminating device as described in any one of Claims 1-6,
The light guide plate includes the light bending portion formed by a plurality of the groove portions and the light bending portion formed between the groove portions to bend light in the light guide direction and guide the remaining light to the outside. An illumination device comprising: a partial light bending portion. The lighting device according to claim 7.
An illuminating device, wherein a diffusing member is provided at least in a position facing the partial light bending portion. In the illuminating device as described in any one of Claims 1-6,
The said groove part has a diffusivity, and it is comprised in the aspect which a part of light leaks outside the said light-guide plate, The illumination device characterized by the above-mentioned. The lighting device according to claim 9.
An illuminating device, wherein a diffusing member is provided at least at a position facing the groove. In the illuminating device as described in any one of Claims 1-10,
An illumination device comprising: a substrate on which the light source is provided; a housing for fixing the light guide plate; and a diffusion transmission plate provided so as to cover an opening of the housing.