DE112017004282T5 - LEVEL LIGHTING DEVICE - Google Patents

Abstract

A planar lighting device (10) according to an embodiment comprises: a light strip (14, 140, 141, 142, 143, and 144) having an output surface (14c, 140d, 141c, 142c, 143c, and 144a) that receives light incident on entering, outputting and having a plurality of first prisms (14x) formed on the discharge surface (14c, 140d, 141c, 142c, 143c and 144a) in a first direction; a light source (13a and 13b) that emits light entering the light bar (14, 140, 141, 142, 143 and 144); a lightguide plate (16) which guides light entering through a light entrance surface (16c) onto an output surface (16a); and a prism plate (15) disposed between the output surface (14c, 140d, 141c, 142c, 143c, and 144a) of the light bar (14, 140, 141, 142, 143, and 144) and the light entrance surface (16c) of the light guide plate (16). is arranged and has a plurality of second prisms (15i) which, in a second direction which intersects the first direction, at a surface which the output surface (14c, 140d, 141c, 142c, 143c and 144a) of the light strip (14, 140, 141, 142, 143 and 144) are formed.

Description

area

The present invention relates to a planar lighting device.

General state of the art

Designed to be developed level (also known as planar or planar) lighting devices for built-in taillights such as high brake lights used by vehicles. Such planar illumination devices include, for example, each a light source, a mirror and a lens.

List of citations

patent literature

Patent Literature 1: Disclosed Japanese Patent Application No. 2015-179603

Summary

Technical problem

With planar lighting devices, it is difficult to maintain light transmission and to control light distribution and luminance distribution.

In view of the above-described drawback, the present invention aims to provide a planar lighting device which can easily control light distribution and luminance distribution.

Solution for problem

In order to solve the above-described problems and achieve the object, a planar lighting device according to one aspect of the present invention includes a light bar that outputs an output surface which emits light entering therein, and a plurality of first prisms attached to the output surface a light source which emits light entering the light bar, a light guide plate which guides light entering through a light entrance surface onto an output surface, a prism plate disposed between the output surface of the light bar and the light entrance surface the light guide plate is arranged and has a plurality of second prisms, which are in a second direction which intersects the first direction, side by side on a surface which faces the output surface of the light bar, are formed.

Advantageous Effects of the Invention

An aspect according to the present invention can easily control a light distribution and luminance distribution.

list of figures

• 1 FIG. 10 is a front view of a planar lighting device according to a first embodiment. FIG.
• 2 is a sectional view taken along the line AA in 1 ,
• 3 FIG. 14 is a view for explaining a light bar according to the first embodiment. FIG.
• 4 is an enlarged view of a part of a first part and a second part.
• 5 FIG. 14 is a view for explaining fourth prisms formed on a surface opposite to an output surface of the light bar according to the first embodiment. FIG.
• 6 FIG. 16 is a view for explaining the fourth prisms formed on a surface opposite to the output surface of the light bar according to the first embodiment. FIG.
• 7 FIG. 12 is a view for explaining first prisms formed on an output surface of the light bar according to the first embodiment. FIG.
• 8A FIG. 16 is a view for explaining a prism plate according to the first embodiment. FIG.
• 8B FIG. 14 is a view for explaining the prism plate according to the first embodiment. FIG.
• 9 FIG. 14 is a view for explaining the prism plate according to the first embodiment. FIG.
• 10 FIG. 16 is a view for explaining a light guide plate according to the first embodiment. FIG.
• 11 is a view for explaining the light guide plate according to the first embodiment.
• 12 is a view for explaining the light guide plate according to the first embodiment.
• 13 FIG. 12 is a diagram for explaining the light guide plate according to the first embodiment. FIG.
• 14 FIG. 12 is a diagram for explaining the light guide plate according to the first embodiment. FIG.
• 15 is a graph of the relationship between first simulation results and Arrangement angles and prism angles corresponding to the respective arrangement angles calculated by formula (3).
• 16 Fig. 12 is a view for explaining the relationship between the thickness of the light guide plate, the output angle, the refractive index of the light guide plate, and the distance for uniformly outputting light from the entire output surface of the light guide plate.
• 17 Fig. 12 is a diagram of a light distribution graph obtained from a second simulation.
• 18 Fig. 12 is a diagram of a light distribution graph obtained from the second simulation.
• 19 Fig. 12 is a diagram of a luminance distribution graph obtained from a third simulation.
• 20 Fig. 16 is a view for explaining a first modification of the first embodiment.
• 21 Fig. 16 is a view for explaining a second modification of the first embodiment.
• 22 FIG. 10 is a front view of the planar lighting device according to a second embodiment. FIG.
• 23 FIG. 14 is a view for explaining a first modification of the second embodiment. FIG.
• 24 Fig. 13 is a view for explaining a second modification of the second embodiment.

Description of embodiments

Hereinafter, planar lighting devices according to the embodiments will be described with reference to the accompanying drawings. The embodiments described below are not intended to limit the use of the planar lighting devices. The drawings are schematic, and it should be noted that the relationship between the sizes of the components and the component portion may differ from that in an actual design. The drawings may include parts where the relationship between the sizes of the components and the component portion is different.

First Embodiment

An overview of the structure of a planar lighting device 10 is with reference to 1 and 2 given. 1 FIG. 10 is a front view of the planar lighting device according to a first embodiment. FIG. 2 is a sectional view taken along the line AA in 1 ,

As in 1 illustrated, includes the planar lighting device 10 a linear light source 20 , a case frame 11 , flexible printed circuit boards (FPCs) 12a and 12b and a light guide plate 16 , The linear light source 20 includes light emitting diodes (LEDs) 13a and 13b , a light bar 14 and a prism plate 15 , The plane lighting device 10 is used, for example, for elevated brake lights of vehicles.

The case frame 11 stops and takes on a part of the linear light source 20 , the light guide plate 16 and other components. The case frame 11 is made of synthetic resin and / or metal, for example. For ease of explanation, the illustration of a part of the housing frame 11 shortened in the plus direction of a Z-axis.

The FPC 12a is a substrate on which the LED 13a is attached. The FPC 12a has a mounting surface 12A_1 on. At the mounting surface 12A_1 is a surface placed, which is a light exit surface 13a_1 the LED 13a is opposite.

The FPC 12b is a substrate on which the LED 13b is attached. The FPC 12b has a mounting surface 12b_1 on. At the mounting surface 12b_1 is a surface placed, which is a light exit surface 13b_1 the LED 13b is opposite.

The FPCs 12a and 12b are connected to a drive circuit, which is not shown. In other words, the LEDs 13a and 13b each using the drive circuit via the FPCs 12a and 12b controlled, causing the LEDs 13a and 13b Emit light (the LEDs 13a and 13b to shine).

The LEDs 13a and 13b are point light sources. The LED 13a has the light exit surface 13a_1 on, which emits light. The LED 13b has the light exit surface 13b_1 on, which emits light. The LED 13a is side by side with a light entry surface 14a the light bar 14 arranged, wherein the light exit surface 13a_1 the light entry surface 14a the light bar 14 is facing. The LED 13b is side by side with a light entry surface 14b the light bar 14 arranged, wherein the light exit surface 13b_1 the light entry surface 14b the light bar 14 is facing. As a result, the LED emits 13a Light entering the light entry surface 14a enters, and the LED 13b emits light that enters the light entry surface 14b entry. As described above, the area is that of the light exit surface 13a_1 the LED 13a is opposite, at the mounting surface 12A_1 placed, and the area that the Light-emitting surface 13b_1 the LED 13b is opposite, is at the attachment surface 12b_1 placed. In other words, the LEDs are 13a and 13b upwardly directed LEDs. Alternatively, the LEDs 13a and 13b be also side-facing LEDs.

The LEDs 13a and 13b according to the present embodiment are connected in parallel. Therefore, if one of the LEDs 13a and 13b is disconnected, the other of which is turned on.

The light bar 14 converts light from the LEDs 13a and 13b , which serve as a point light source, from entering into this, in linear light and gives the linear light to the light guide plate 16 out. The light bar 14 has a rod-like shape and has the light entry surfaces 14a and 14b , an output area 14c and a surface 14d , the output area 14c is opposite, up. The light entry surface 14a receives light through the LED 13a is emitted. The light entry surface 14b receives light through the LED 13b is emitted. The output area 14c outputs the received light. At the output area 14c are several first prisms 14x (please refer 7 ), which will be described later, in the transverse direction (Z-axis direction (first direction)) of the light bar 14 educated. At the surface 14d are several fourth prisms 14u (please refer 5 ), which will be described later, in the longitudinal direction (X-axis direction) of the light bar 14 educated.

The prism plate 15 controls a distribution of light. The prism plate 15 is between the output area 14c the light bar 14 and a light entrance surface 16c the light guide plate 16 arranged. The prism plate 15 has an area 15a , the output area 14c the light bar 14 facing, and a surface 15b that of one surface 15a is opposite, up. On one surface 15a are several second prisms 15i (please refer 8A . 8B and 9 ), which will be described later, side by side in the longitudinal direction (X-axis direction (second direction)) of the prism plate 15 educated. The second direction is orthogonal to the first direction described above. The second direction only has to cut the first direction. The area 15b is a plane that runs parallel to the XZ plane.

The width of the area in which the luminance of the linear light source 20 (more precisely the area 15b the prism plate 15 ) is uniform (the range in which the ratio between the maximum value and the minimum value (minimum / maximum) of the luminance made by equalization in the thickness direction (Z-axis direction) and a resolution equal to or less than 1 mm is more preferable is equal to or less than 0.5 mm in the width direction (X-axis direction), equal to or higher than 60%, more preferably equal to or higher than 80%), is preferably equal to or larger than the width of the light entrance surface 16c the light guide plate 16 ,

The light guide plate 16 is made of a transparent material (eg, polycarbonate resin) and has a rectangular shape in a plan view. The light guide plate 16 has two main surfaces 16a and 16b (please refer 2 ) and the light entrance side surface (light entrance surface) 16c , which serves as a side surface with which the prism plate 15 Is arranged side by side, up. The main surfaces 16a and 16b are rectangular areas that extend along the XY plane. The light entry surface 16c is a strip-shaped area extending in the X-axis direction. The light entry surface 16c receives light, its distribution through the prism plate 15 is controlled. The main area 16a is an output surface, the light passing through the light entry surface 16c enters, spends. In the following description, the "major surface 16a" may be referred to as an "output surface 16a". At the main surface 16b , the output area 16a the light guide plate 16 Opposite are several third prisms 16f (please refer 10 ), which will be described later, are formed side by side in a third direction (Y-axis direction) orthogonal to the above-described first direction and second direction. The third direction only has to intersect the first direction and the second direction. The third prisms 16f change the direction of movement of light that is in the light guide plate 16 moves, and the light gets out of the output area 16a output. As described above, guides the light guide plate 16 that through the light entry surface 16c incoming light (directs received light). In particular, the light guide plate conducts 16 the received light on the output surface 16a , The light guide plate 16 has a desirable translucency. For example, the light guide plate 16 a light transmission such that it is completely transparent, and that allows an object behind the main surface 16b , the output area 16a is opposite, from the output area 16a can be considered from.

The following is the light bar 14 according to the present embodiment with reference to 3 to 7 described. 3 is a view for explaining the light bar according to the first embodiment. As in 3 shown, points the light bar 14 a first part 14h and a second part 14i on which have a wedge shape in which the width (dimension in the Y-axis direction), in the longitudinal direction (X-axis direction) of the light bar 14 , from a first end 14e towards a middle 14f decreases. The light bar 14 also has a third part 14j and a fourth part 14k on, which have a wedge shape, wherein the width of a second end 14g in the direction the middle 14f decreases. As in 3 shown, is the shape of the light bar 14 with respect to a line segment that, in a sectional view along the XY plane, passes through the center 14f and parallel to the Y axis, line symmetric. In other words, the line segment extends along the Y-axis direction.

As in 3 illustrated, includes the first part 14h a part of the output area 14c and a surface 14l that is the part of the output area 14c is opposite. The second part 14i includes a part of the output surface 14c and a surface 14m that is the part of the output area 14c is opposite. The third part 14j includes a part of the output surface 14c and a surface 14n that is the part of the output area 14c is opposite. The fourth part 14k includes a part of the output surface 14c and a surface 140 that is the part of the output area 14c is opposite.

4 is an enlarged view of a part of the first part and the second part. As in 4 is an angle φ1 that is between a plane 14p parallel to the surface 15b the prism plate 15 is, and the area 14l is formed, in a sectional view along the XY plane, greater than an angle φ2, which is between a plane 14q parallel to the surface 15b is, and the area 14m is formed. Likewise, an angle is between a plane that is parallel to the surface 15b is, and the area 14n is formed, in a sectional view along the XY plane, greater than an angle between a plane parallel to the surface 15b is, and the area 140 is formed.

Hereinafter, the fourth prisms formed on the surface opposite to the output surface of the light bar according to the first embodiment will be explained with reference to FIG 5 and 6 described. 5 and 6 FIG. 12 are views for explaining the fourth prisms formed on the surface opposite to the output surface of the light strip according to the first embodiment. FIG.

5 FIG. 16 is a view for explaining the fourth prisms which, in the longitudinal direction (X-axis direction) of the surface 14d the light bar 14 , in the 3 is shown, in one part 21 near the center and closer to the light entrance surface 14a as to the middle 14f lies, are trained. 6 Fig. 13 is a view for explaining the fourth prisms, in the longitudinal direction of the surface 14d the light bar 14 , in the 3 is shown, in one part 22 that is closer to the first end 14e lies, are trained.

As in 5 are shown, are several fourth prisms 14u in the longitudinal direction (X-axis direction (second direction)) of the light bar 14 in which part 21 on the surface 14d Formed side by side. The fourth prisms 14u each have a fifth area 14s and a sixth area 14t on. The fifth area 14s declines, in terms of the output area 14c , in the longitudinal direction of the light strip 14 in a direction away from the output area 14c from the first end 14e (please refer 3 ) towards the middle 14f (please refer 3 ). The sixth area 14t declines, in terms of the output area 14c , in the longitudinal direction of the light strip 14 in a direction towards the output surface 14c from the first end 14e (please refer 3 ) towards the middle 14f (please refer 3 ). In other words, the fifth range tends 14s and the sixth area 14t in terms of area 15b the prism plate 15 , The sixth area 14t a certain fourth prism 14u is with the fifth area 14s of the definite fourth prism 14u connected.

Equally, as in 6 are shown, are several fourth prisms 14u Side by side, in the longitudinal direction (X-axis direction (second direction)) of the light bar 14 in which part 22 on the surface 14d educated.

The shape of the fourth prisms 14u is, in a sectional view along the XY plane, with respect to a line segment passing through the middle 14f and parallel to the Y-axis direction, line symmetric. The line segment extends along the Y-axis direction. In other words are on the surface 14d several fourth prisms 14u Formed side by side in the X-axis direction. The fourth prisms 14u each have the fifth area 14s and the sixth area 14t that with the fifth area 14s is connected. The fifth area 14s declines, in terms of the output area 14c , in a direction away from the output area 14c , and the sixth area 14t declines, in terms of the output area 14c in a direction towards the output area 14c from the ends (the first end 14e (please refer 3 ) and the second end 14g (please refer 3 )) towards the center 14f the light bar 14 in the X-axis direction (second direction).

An angle φ3 (see 5 ) is, in a sectional view along the XY axis, between the sixth area 14t of the fourth prism 14u in the middle 14f the light bar 14 and a virtual level 14r (Surface 15b) which is parallel to a virtual plane 14aa, which will be described later in detail. An angle φ4 (see 6 ) is between the sixth area 14t of the fourth prism 14u at the ends (the first end 14e (please refer 3 ) and the second end 14g (please refer 3 )) of the light bar 14 and the plane 14r (Surface 15b) educated. The angle φ3 is greater than the angle φ4. The angle between the sixth area 14t of the fourth prism 14u and the plane 14r (Surface 15b) is formed, changes so continuously that he from the middle 14f towards the ends (the first end 14e (please refer 3 ) and the second end 14g (please refer 3 )) of the light bar 14 gradually decreases.

The angle, in a sectional view along the XY plane, between the fifth area 14s and the sixth area 14t is formed, is an angle φ5, the fourth prism 14u in the middle 14f the light bar 14 and the fourth prism 14u at the ends of the light bar 14 is common.

Using the fourth prisms 14u on the surface 14d are formed, the planar lighting device 10 the distribution of light (light distribution) and the luminance distribution in the X-axis direction at the output surface 14c the light bar 14 easy to control. As a result, the planar lighting device 10 the light distribution and luminance distribution in the X-axis direction on the output surface 16a the light guide plate 16 exactly control.

Hereinafter, the first prisms formed on the output surface of the light bar according to the first embodiment will be explained with reference to FIG 7 described. 7 FIG. 16 is a view for explaining the first prisms formed on the output surface of the light bar according to the first embodiment. FIG. 7 represents a side surface of the light bar 14 represents.

As in 7 are shown, in a sectional view along the YZ plane, a plurality of first prisms 14x in the transverse direction (Z-axis direction (first direction)) of the light bar 14 Side by side on the output surface 14c the light bar 14 educated. The first prisms 14x each have a seventh area 14v and an eighth area 14w on. The seventh area 14v tilts, in relation to the plane 14aa, which is parallel to the surface 15b the prism plate 15 is, in a direction away from the plane 14d from a first end 14y (End in the minus direction of the Z-axis) towards a second end 14z (End in the plus direction of the Z axis) in the transverse direction of the light bar 14 , The eighth area 14w Tilts, in relation to the plane 14aa , in a direction towards the surface 14d from the first end 14y towards the second end 14z in the transverse direction of the light bar 14 ,

An angle φ6 that is between the seventh range 14v and the eighth area 14w is formed (opening angle of the first prism 14x) , for example, is 90 degrees. An angle φ7 that is between the seventh range 14v and the plane 14aa is formed, and an angle φ8 that is between the eighth region 14w and the plane 14aa is 45 degrees, for example.

Like in 7 represented, becomes a path of light 80 in the light bar 14 enters, through the first prism 14x changed in a direction parallel to the Y-axis direction. The light 80 whose path is changed, enters the one surface 15a (please refer 1 ) of the prism plate 15 on. As described above, the first prisms control 14x the distribution of light in the Z-axis direction. Besides, the above-described fourth prisms are 14u on the surface 14d , the output area 14c the light bar 14 is opposite, trained. By changing the opening angle of the first prisms 14x at the output area 14c are formed, for example, the planar lighting device 10 a distribution of light (light distribution) and a luminance distribution in the Z-axis direction on the output surface 14c the light bar 14 change. As a result, the planar lighting device 10 a distribution of light (light distribution) and a luminance distribution in the Y-axis direction on the output surface 16a the light guide plate 16 easy to control.

When the angle φ6 of the opening angle of the first prism is 14 × 90 degrees, the width of the distribution of light in the Z-axis direction is at the output surface 16a the light guide plate 16 narrowest. When the angle φ6 is larger than 90 degrees, the width of the distribution of light in the Z-axis direction at the output surface is 16a the light guide plate 16 set wider.

The following is the prism plate 15 according to the first embodiment with reference to 8A . 8B and 9 described. 8A . 8B and 9 are views for explaining the prism plate according to the first embodiment.

8A and 8B FIG. 12 are views for explaining the second prisms which, in the longitudinal direction (X-axis direction), in one part. FIG 15c near the middle of the in 1 illustrated prism plate 15 are formed. 9 is a view explaining the second prisms in one part 15d which, in the longitudinal direction, is closer to a first end 15e the in 1 illustrated prism plate 15 is, are trained.

As in 8A shown are several second prisms 15i in the longitudinal direction (X-axis direction (second direction)) of the prism plate 15 in which part 15c Side by side on one surface 15a educated. The second prisms 15i each have a first area 15g and a second area 15h on. The first area 15g tilts, in terms of area 15b in the longitudinal direction of the prism plate 15 , in a direction away from the plane 15b (please refer 1 ) from the first end 15e (please refer 1 ) towards a center 15k (please refer 1 ). The second area 15h tilts, in terms of area 15b in the longitudinal direction of the prism plate 15 , in a direction towards the surface 15b from the first end 15e towards the middle 15k , The second area 15h a particular second prism 15i is with the first area 15g of the particular second prism 15i connected.

As in 8A represented, becomes a path of light 81 that in the one area 15a the prism plate 15 enters, through the second prism 15i changed in a direction parallel to the Y-axis direction. The light 81 whose path is changed enters the light entry area 16c (please refer 1 ) of the light guide plate 16 on. More precisely, the light is 81 that in the first area 15g of the second prism 15i enters, through the second area 15h in the direction of the surface 15b reflected. As described above, the second prisms control 15i the distribution of light in the X-axis direction.

Equally, as in 9 shown are several second prisms 15i in the longitudinal direction (X-axis direction (second direction)) of the prism plate 15 Side by side in the part 15d on one surface 15a educated.

The shape of the second prisms 15i is, in a sectional view along the XY plane, with respect to a line segment passing through the middle 15k (please refer 1 ) and parallel to the Y-axis direction, line symmetric. The line segment extends along the Y-axis direction. In other words, on one surface 15a several second prisms 15i Formed side by side in the X-axis direction. The second prisms 15i each have the first area 15g and the second area 15h that with the first area 15g is connected. The first area 15g tilts, in terms of area 15b , in a direction away from the plane 15b , and the second area 15h tilts, in terms of area 15b , in a direction towards the surface 15b , from the ends (the first end 15e (please refer 1 ) and a second end 15f (please refer 1 )) towards the center 15k the prism plate 15 in the X-axis direction (second direction).

An angle φ10 (see 8A) is, in a sectional view along the XY plane, between the first area 15g of the second prism 15i in a middle part (part 15c) , the middle one 15k includes, and a surface 15j parallel to the surface 15b is formed. An angle φ12 (see 9 ) is between the first area 15h of the second prism 15i at the ends (the first end 15e (please refer 1 ) and the second end 15f (please refer 1 )) of the prism plate 15 and the plane 15j educated. The angle φ10 is smaller than the angle φ12. In other words, the angle (inclination angle) is φ10 with respect to the area 15b , the first area 15g of the second prism 15i which is in the middle part of one area 15a is formed in the X-axis direction (second direction), none as the angle (inclination angle) φ12 with respect to the surface 15b , the first area 15g which is at the ends of one surface 15a is formed in the X-axis direction.

An angle φ11 (see 8A) is, in a sectional view along the XY plane, between the second area 15h of the second prism 15i in the middle 15k (Part 15c) and the plane 15j educated. An angle φ13 (see 9 ) is between the second area 15h of the second prism 15i at the ends of the prism plate 15 and the plane 15j educated. The angle φ11 is larger than the angle φ13. In other words, the angle (inclination angle) is φ11 with respect to the surface 15b , the second area 15h of the second prism 15i which is in the middle part of one area 15a is formed in the X-axis direction (second direction), none as the angle (inclination angle) φ13 with respect to the surface 15b , the second area 15h which is at the ends of one surface 15a is formed in the X-axis direction.

The angle, in a sectional view along the XY plane, between the first area 15g and the second area 15h is formed, is an angle φ9, the second prism 15i in the middle 15k the prism plate 15 and the second prism 15i at the ends of the prism plate 15 is common.

Suppose a case in which, as in 8A represented, a line segment 71 which, in a sectional view along the XY plane, passes through the center 15k (please refer 1 ) and parallel to the Y-axis direction, passing through the angle that extends between the first region 15g a particular second prism 15i and the second area 15h a particular second prism 15i is formed. In this case, the angle φ10 that is between the first area 15g of the second prism 15i in the middle part (part 15c) and the plane 15j is formed, equal to the angle φ11, between the second area 15h and the plane 15j is formed. In other words, the shape of the second prism 15i in the middle part (part 15c) in a sectional view along the XY plane, an isosceles triangle.

Suppose a case in which, as in 8B represented, a line segment 72 which, in a sectional view along the XY plane, passes through the center 15k (please refer 1 ) and parallel to the Y-axis direction, through the boundary between the second region 15h a particular second prism 15i and the first area 15g of the other second prism 15i , side by side with the particular second prism 15i is arranged, runs. In this case, the angle φ10, which is between the first area 15g of the particular second prism 15i in the middle part (part 15c) and the plane 15j is formed, the angle φ11, which is between the second area 15h of the particular second prism 15i and the plane 15j is formed, the angle φ10, which is between the first area 15g of the other second prism 15i and the plane 15j is formed, and the angle φ11, the between the second area 15h of the other second prism 15i and the plane 15j is formed, equal to each other. In other words, the shape of the determined second prism 15i and the other second prism 15i in the middle part (part 15c) in a sectional view along the XY plane, an isosceles triangle.

As described above, the shape of the second prisms 15i in a sectional view along the XY plane, with respect to a line segment passing through the center 15k and parallel to the Y-axis direction (third direction), line symmetric. That is, the line segment extends along the Y-axis direction. As in 9 represented, becomes a path of light 82 that through the LED 13b is emitted and in the one area 15a enters, through the second prism 15i that, in the X-axis direction, closer to the LED 13a as to the middle 15k is formed, changed to a direction which is parallel to the Y-axis direction. The light 82 whose path is changed enters the light entry area 16c (please refer 1 ) of the light guide plate 16 on. As described above, the second prisms 15i closer to the LED 13a as to the middle 15k are configured to perform a light distribution control on the light passing through the LED 13b is emitted. Likewise, the second prisms 15i , which, in the X-axis direction, is closer to the LED 13b as to the middle 15k are configured to perform a light distribution control on the light passing through the LED 13a is emitted. As a result, the planar lighting device 10 if any of the LEDs 13a and 13b on both sides of the light bar 14 are arranged, disconnected (turned off) and only the other of them is on, keeping the light distribution substantially equal to the light distribution achieved when both of the LEDs 13a and 13b are turned on.

The area 15b the prism plate 15 is a flat surface. However, as in 8a . 8B and 9 represented, the area can be 15b be provided with a lenticular lens, the more convex lenses 30 which are arranged side by side in the X-axis direction (second direction). By increasing the contact angle between the convex lenses 30 and the area 15b For example, the light distribution angle can be widened in the X-axis direction. As described above, the distribution of light (light distribution) in the X-axis direction can be adjusted by adjusting the contact angle between the convex lenses 30 and the area 15b , easily controlled. As a result, the planar lighting device 10 the distribution of light (light distribution) in the X-axis direction at the output surface 16a the light guide plate 16 easy to control.

By the spacing intervals between the adjacent convex lenses 30 smaller than the intervals between the adjacent second prisms 15i can be made, the homogeneity of the luminance in the X-axis direction can be easily improved. As a result, the planar lighting device 10 the luminance distribution in the X-axis direction on the output surface 16a the light guide plate 16 easy to control.

The following is the light guide plate 16 according to the first embodiment with reference to 10 to 14 described. 10 to 14 are views for explaining the light guide plate according to the first embodiment.

As in 10 shown are several third prisms 16f in the transverse direction (Y-axis direction (third direction)) of the light guide plate 16 , on the main surface (area) 16b , the output area 16a the light guide plate 16 is opposite, formed side by side. The third prisms 16f each have a third area 16d and a fourth area 16e on. The third area 16d is an area (an area) that is parallel or substantially parallel to the output area 16a is. Like in 11 is the third area 16d an area in which an angle φ14, with respect to a plane 16h parallel to the output surface 16a is equal to or greater than 0 degrees and equal to or less than 4 degrees. The angle φ14 is preferably equal to or greater than 0 degrees and equal to or less than 1 degree, and more preferably equal to or greater than 0 degrees and equal to or less than 0.5 degrees.

As described above, the third area is 16d parallel or substantially parallel to the output surface 16a , If an object is behind the main surface 16b , the output area 16a the light guide plate 16 is opposite, located, from the output area 16a is considered, the object considered has a high physical continuity. In other words, distortion of the object under consideration is suppressed. Accordingly, the light guide plate 16 the desired light transmittance described above.

The fourth area 16e declines, in terms of the output area 16a in a direction towards the output area 16a , from the light entry surface 15c (please refer 1 ) of the light guide plate 16 in the direction of a surface 16g that the light entry surface 16c is opposite. The fourth area 16e one certain third prism 16f is with the third area 16d of the particular third prism 16f connected.

P1 is the ratio of a length L1 of the third area 16d in the Y-axis direction (third direction) (dimension of the third area 16d in the Y-axis direction) to a length L3 of the third prism 16f in the Y-axis direction (third direction) (dimension of the third prism 16f in the Y-axis direction). The relationship P1 is equal to or greater than 0.6 (60%) and less than 1.0 (100%). The relationship P1 is expressed by formula (1): $$\text{P1}=\text{L1 / L3}$$

The length L3 is the sum of the length L1 and a length L2 of the fourth area 16e in the Y-axis direction (dimension of the fourth area 16e in the Y-axis direction). The length L3 is expressed by formula (2): $$\text{L3}=\text{L1}+\text{L2}$$

An angle (prism angle) φ15, which, in a sectional view along the YZ plane, between the plane 16h and the fourth area 16e is expressed by formula (3): $$\mathrm{<figure-callout\; id="15"\; label="\phi "\; filenames="DE112017004282T5\_0006.png,DE112017004282T5\_0010.png"\; state="\{\{state\}\}">\phi </figure-callout>}15=\left\{90-\text{asin}\left(\text{sin}\mathrm{\theta }\text{/ n}\right)\right\}/2$$

Formula (3) is satisfied when the angle φ6 (see 7 ) of the opening angle of the above-described first prism 14x is about 90 degrees (90 ± 5 degrees), and when the third range described above 16d parallel or substantially parallel to the output surface 16a is. In formula (3), "n" is the refractive index of the lightguide plate 16 , and "θ" is the angle expressed by formula (4): $$\mathrm{\theta }=90-\mathrm{<figure-callout\; id="1"\; label="\theta "\; filenames="DE112017004282T5\_0006.png,DE112017004282T5\_0015.png"\; state="\{\{state\}\}">\theta </figure-callout>}1$$

Like in 12 4, "θ1" in Formula (4) denotes an angle (arrangement angle) which, in a plan view along the YZ plane, is between a horizontal direction 17 and the output area 16a is formed when the planar lighting device 10 as a raised brake light on a rear window of a vehicle (not shown) is mounted. In the present embodiment, "θ" denotes an angle (output angle) between a vertical direction 18 the output area 16a and a direction of movement 19 (horizontal direction 17 ) of light coming out of the output area 16a the light guide plate 16 is issued is formed. In other words, "θ" denotes an output angle of light coming out of the output surface 16a is issued. While several rays of light from the output surface 16a are output in multiple directions, gives the light movement direction 19 a direction in which light of the light beams moves, which has a peak light intensity.

In the following, results of a first simulation (first simulation results), which are based on a model of the planar illumination device 10 is performed according to the first embodiment is described. The first simulation is done to the arrangement angles θ1 in the minimum luminous flux of the LEDs 13a and 13b and the prism angles φ15 corresponding to the respective arrangement angles θ1 which are obtained when the planar lighting device 10 meets the light distribution requirements for elevated brake lights, to calculate.

Before explaining the first simulation results, the light distribution specifications for the high-mounted brake lights are described below. 13 and 14 are diagrams for explaining the light distribution specifications for high brake lights. Hereinafter, the light distribution specifications will be described using a typical planar lighting device as an example. A planar illumination device is placed on a table that can be biaxially rotated in two directions of the horizontal direction and the vertical direction (vertical direction). A photometer, which measures the light intensity (cd) of light output from an output surface of the planar illumination device, is placed in a position facing the output surface, the angle of the table being 0 degrees in the horizontal direction and 0 degrees in the horizontal direction vertical direction is set. As in 13 and 14 shown, the light distribution requirements for high-mounted brake lights are as follows: when the angle of the table o degrees (H) in the vertical direction and -10 degrees ( 10L) in the horizontal direction, the light intensity measured by the photometer should be equal to or higher than 16 cd. In the 13 and 14 shown light distribution specifications indicate that when the angle of the table 0 degrees (H) in the vertical direction and -5 degrees ( 5L) in the horizontal direction is, the light intensity measured by the photometer should be equal to or higher than 25 cd. In the 13 and 14 The light distribution specifications shown indicate that when the angle of the table is o degrees (H) in the vertical direction and o degrees (V) in the horizontal direction, the light intensity measured by the photometer should be equal to or higher than 25 cd. In the 13 and 14 shown light distribution specifications indicate that when the angle of the table o degrees (H) in the vertical direction and 5 degrees ( 5R) in the horizontal direction, the light intensity measured by the photometer should be equal to or higher than 25 cd. In the 13 and 14 shown light distribution specifications indicate that when the angle of the table o degrees (H) in the vertical direction and 10 degrees ( 10R) in the horizontal direction, the light intensity measured by the photometer should be equal to or higher than 16 cd. The light distribution specifications are the same for the other angles in the vertical direction ( 5 Degree ( 5U) . 10 Degree ( 10U) and -5 degrees ( 5D) ) Are defined. "-" in 14 indicates that there is no corresponding intensity of the specifications.

15 FIG. 12 is a graph of the relationship between the above-described first simulation results and the above-described arrangement angles and the prism angles corresponding to the respective arrangement angles calculated by formula (3). 15 Fig. 12 is a graph indicating the relationship between the first simulation results and the arrangement angles θ1 and the prism angles φ15 corresponding to the respective arrangement angles θ1 calculated by formula (3).

The abscissa of the graph in 15 shows arrangement angle θ1 on, and the ordinate indicates prism angle φ15. In the graph set white circles 32 the arrangement angle θ1 and the prism angles φ15 obtained as the first simulation results, and black circles 31 set the arrangement angles θ1 and the prism angles φ15 (calculation results) calculated by formula (3).

As in the graph in 15 5, there is a difference of about 5 degrees between the prism angles φ15 calculated by formula (3) and the prism angles φ15 generated by the simulation for the same arrangement angle θ1 to be obtained. More specifically, there is a difference of about 2 degrees. As a result, the planar lighting device 10 According to the present embodiment, an angle within a range equal to or greater than an angle obtained by subtracting 5 degrees from the prism angles φ15 calculated by formula (3) and equal to or smaller than an angle which is obtained by adding 5 degrees to the prism angles φ15 calculated by formula (3), as the angle between the plane 16h and the fourth area 16e (please refer 10 ) is formed. Preferably, the planar lighting device 10 an angle within a range equal to or greater than an angle obtained by subtracting 2 degrees from the prism angles φ15 calculated by formula (3) and equal to or smaller than an angle obtained by adding 2 degrees to the prism angles φ15 calculated by formula (3) is defined as defining the angle between the plane 16h and the fourth area 16e (please refer 10 ) is formed.

In order to meet the light distribution requirements for high-intensity brake lights with lower luminous flux, the output angle is θ preferably greater than 0 degrees and equal to or less than 65 degrees. To a light leakage from the main surface 16b , the output area 16a the light guide plate 16 opposite, to suppress (light emission at the back) is the output angle θ preferably equal to or greater than 20 degrees and equal to or less than 65 degrees. If the output area 16a is subjected to a low-reflection treatment, the output angle θ greater than 0 degrees and equal to or less than 65 degrees. The low-reflection treatment is a processing, for example, for forming a dielectric multilayer film or a moth-eye structure on the output surface 16a for the suppression of reflected light. The low-reflection treatment suppresses reflection of light into the light guide plate 16 through the output area 16a ,

The following is the relationship between a thickness H the light guide plate 16 , the output angle θ , the refractive index n the light guide plate 16 and a distance x , which will be described later, for uniformly emitting (emitting) light from the entire output surface 16a the light guide plate 16 , described. 16 Fig. 12 is a view for explaining the relationship between the thickness of the light guide plate, the output angle, the refractive index of the light guide plate, and the distance for uniformly outputting light from the entire output surface of the light guide plate.

In the 16 illustrated relationship between the thickness h of the light guide plate 16 , the output angle θ , the refractive index n the light guide plate 16 and the distance x is preferably expressed by formula (5): $$\text{x}\ge \text{H}\cdot \text{tan}\left[\text{asin}\left\{\left(\text{sin}\mathrm{\theta }\right)/\text{n}\right\}\right]$$

The distance x in formula (5) is a distance (a length) from one end 11a to a point 16k in the Y-axis direction. The end 11a is one end of the rack 11 closer to the surface 16g and to the side of the output surface 16a is. The point 16k is a point on which a surface 16i parallel to the output surface 16a is, with an area 16j connected, which is closer to the output surface 16a , from the light entry surface 16c (please refer 1 ) in the direction of the surface 16g on the main surface 16b the light guide plate 16 inclines. As in 16 illustrated, includes the light guide plate 16 one wedge-shaped part in which the width (dimension in the Z-axis direction) of the light entrance surface 16c (please refer 1 ) in the direction of the surface 16g decreases.

Suppose a case in which the plane lighting device 10 is attached as a raised brake light on a rear window of a vehicle (not shown), as in 12 shown. In this case, a length (transmission length) L4 from one end 74 of the case frame 11 on the lower side in the vertical direction (vertical direction) and on the side of the main surface 16b to the lower end of the light guide plate 16 in the vertical direction preferably equal to one length (light emission length) L5 from one end 73 of the case frame 11 on the lower side in the vertical direction and on the side of the output surface 16a to the lower end of the light guide plate 16 in the vertical direction.

In the following, those from a second simulation, which are based on a model of the planar illumination device 10 According to the present embodiment, results obtained (second simulation results) are described. The second simulation is performed to determine the light distribution that is obtained when the LEDs 13a and 13b on both sides (both ends) of the light bar 14 are brought to emit light (turned on) (double-sided lighting), and the light distribution that is obtained when from the LEDs 13a and 13b on both sides of the light bar 14 are arranged, only the LED 13a is turned on (one-sided lighting), using the model of the planar lighting device 10 derive. In the second simulation, the light distribution for double-sided illumination and the light distribution for single-sided illumination are obtained on the condition that the total luminous flux of the LEDs 13a and 13b , which serve as the light source in the two-sided illumination, is 100 Im, and that the total luminous flux of the LED 13a which serves as the light source in the one-sided illumination, is 100 Im, that is, under the condition that the total luminous flux of the light source in the two-sided illumination is equal to the total luminous flux of the light source in the one-side illumination. 17 and 18 are graphs of light distribution graphs obtained from the second simulation.

The in 17 The graph shown shows the relationship between the angle (angle in the vertical direction) of the discharge surface 16a the light guide plate 16 in the transverse direction (vertical direction: Y-axis direction) and the light intensity (cd) of light, which in the two-sided illumination and one-sided illumination from the output surface 16a is output with the respective angles. In 17 the abscissa indicates an angle in the vertical direction, and the ordinate indicates a light intensity. In the in 17 displayed graph represents a curve 51 The relationship between the angle in the vertical direction and the light intensity in double-sided lighting, and a curve 52 represents a relationship between the angle in the vertical direction and the light intensity in one-sided illumination.

The in 18 The graph shown shows the relationship between the angle (angle in the horizontal direction) of the discharge surface 16a the light guide plate 16 in the longitudinal direction (horizontal direction: X-axis direction) and the light intensity (cd) of light, in the two-sided illumination and one-sided illumination with the respective angles in the horizontal direction from the output surface 16a is issued. In 18 the abscissa indicates an angle in the horizontal direction, and the ordinate indicates a light intensity. In the in 18 displayed graph represents a curve 53 is the relationship between the angle in the horizontal direction and the intensity of illumination when illuminated on both sides, and a curve 54 represents the relationship between the angle in the horizontal direction and the light intensity in one-sided illumination.

As from the graphs in 17 and 18 shows that the light distribution in two-sided lighting and the light distribution in one-sided lighting are substantially the same. Accordingly, if one of the LEDs 13a and 13b on both sides of the light bar 14 are arranged, separated (turned off), which results in a one-sided lighting, the planar lighting device 10 According to the present embodiment, the light distribution substantially equal to the light distribution with two-sided lighting hold. As a result, the planar lighting device 10 when the lighting condition is changed from double-sided lighting to one-sided lighting that meets light distribution specifications for a high-mounted stop lamp.

In the following, those from a third simulation, which are based on a model of the planar illumination device 10 According to the present embodiment, results obtained (third simulation results) are described. The third simulation is performed to calculate the luminance distribution for double-sided illumination and the luminance distribution for single-sided illumination using the model of the planar illumination device 10 to obtain. In the third simulation, the light distribution for double-sided illumination and the light distribution for single-sided illumination are obtained on the condition that the total luminous flux of the LEDs 13a and 13b , which serves as the light source in the two-sided illumination, is 200 Im, and that the whole Luminous flux of the LED 13a , which serves as the light source in one-sided lighting, is 100 Im. 19 Fig. 12 is a diagram of a luminance distribution graph obtained from the third simulation.

The in 19 The graph shown shows the relationship between the positions in the longitudinal direction (horizontal direction: X-axis direction) on the discharge surface 16a the light guide plate 16 and the luminance at the respective positions with two-sided illumination, and if only the LED 13a the LEDs 13a and 13b is switched on (one-sided lighting), on. In 19 The abscissa indicates a distance in the horizontal direction (position in the horizontal direction) from the center of the discharge surface 16a to the positions in the horizontal direction, and the ordinate indicates a luminance. In the in 19 displayed graph represents a curve 55 the relationship between the horizontal position and the luminance in the case of double-sided illumination, and a curve 56 represents the relationship between the position in the horizontal direction and the luminance in one-sided illumination.

As from the graph in 19 As can be seen, the luminance of the output surface 16a at the one-sided lighting when the side of the LED 13b is not turned on, compared to the two-sided lighting reduced.

It became the plane lighting device 10 described according to the first embodiment. As described above, the planar lighting device 10 According to the first embodiment, the light distribution and luminance distribution are easily controlled.

If one of the LEDs 13a and 13b on both sides of the light bar 14 are arranged, disconnected (turned off) and only the other of which is turned on, the planar lighting device 10 According to the first embodiment, the light distribution is substantially equal to the light distribution achieved when both of the LEDs 13a and 13b are turned on.

First Modification of First Embodiment

20 Fig. 16 is a view for explaining a first modification of the first embodiment. The plane lighting device 10 According to the first embodiment, instead of the in 1 shown light bar 14 one in 20 illustrated light bar 140 include. This embodiment will be described as a first modification of the first embodiment. The light bar 140 has an output surface 140d which is a flat surface. The light bar 140 has a first part 140a , a second part 140b and a third part 140c on. The first part 140a is a wedge-shaped part in which the width (dimension in the Y-axis direction) from a first end (end in the minus direction of the X-axis) in the direction of the plus direction of the X-axis in the longitudinal direction (X-axis direction) Direction) of the light bar 140 decreases. The second part 140b is a wedge-shaped part in which the width is from a second end (end in the plus direction of the X-axis) in the direction of the minus direction of the X-axis in the longitudinal direction of the light strip 140 decreases. The third part 140c is, in a sectional view along the XY plane, a rectangular part and connects the first part 130a and the second part 140b , As in 20 shown, is the shape of the light bar 140 with respect to a line segment which, in a sectional view along the XY plane, passes through the center in the longitudinal direction and parallel to the Y-axis, line symmetrical.

At the output area 140d are several prisms, similar to the first prisms described above 14x (please refer 7 ), in the transverse direction (Z-axis direction (first direction)) of the light bar 140 educated. On the surface, the output surface 140d the light bar 140 are opposite, are several prisms, similar to the fourth prisms described above 14u (please refer 5 ), in the longitudinal direction (X-axis direction) of the light bar 140 educated.

Second Modification of First Embodiment

21 Fig. 16 is a view for explaining a second modification of the first embodiment. The plane lighting device 10 According to the first embodiment, instead of the in 1 shown light bar 14 one in 21 illustrated light bar 141 include. This embodiment will be described as a second modification of the first embodiment. The light bar 141 has an output surface 141c which is a flat surface. The light bar 141 has a first part 141 and a second part 141b on. The first part 141 is a wedge-shaped part in which the width (dimension in the Y-axis direction) from a first end (end in the minus direction of the X-axis) toward a center 141d in the longitudinal direction (X-axis direction) of the light bar 141 decreases. The second part 141b is a wedge-shaped part in which the width from a second end (end in the plus direction of the X-axis) in the direction of the center 141d in the longitudinal direction of the light bar 141 decreases. As in 21 shown, is the shape of the light bar 141 with respect to a line segment which, in a sectional view along the XY plane, passes through the center in the longitudinal direction and parallel to the Y-axis, line symmetrical.

At the output area 141c are several prisms, similar to those described above first prisms 14x (please refer 7 ), in the transverse direction (Z-axis direction (first direction)) of the light bar 141 educated. On the surface, the output surface 141c the light bar 141 are opposite, are several prisms, similar to the fourth prisms described above 14u (please refer 5 ), in the longitudinal direction (X-axis direction) of the light bar 141 educated.

Second Embodiment

While the planar lighting device 10 According to the first embodiment described above, the LEDs 13a and 13b Includes, on both sides of the light bar 14 They can be an LED on only one side of the light bar 14 include. This embodiment will be described as a second embodiment. In the description of the second embodiment, components similar to those according to the first embodiment are denoted by the same reference numerals, and a description thereof is omitted if necessary.

22 FIG. 10 is a front view of the planar lighting device according to the second embodiment. FIG. A planar lighting device 50 according to the second embodiment, as in 22 shown differs from the planar lighting device 10 according to the first embodiment, in that the planar lighting device 50 instead of the light bar 14 a light bar 142 and the LED 13a just on one side of the light bar 142 is arranged comprises.

The LED 13a is a light exit surface of the light bar 142 disposed facing on the side of the minus direction of the X-axis.

The light bar 142 has an output surface 142c which is a flat surface. The light bar 142 has a first part 142a and a second part 142b on. The first part 142a is a wedge-shaped part in which the width (dimension in the Y-axis direction) from a first end (end in the minus direction of the X-axis) in the direction of the plus direction of the X-axis in the longitudinal direction (X-axis direction) Direction) of the light bar 142 decreases. Likewise, the second part 142b a wedge-shaped part in which the width (dimension in the Y-axis direction) from the first end (end in the minus direction of the X-axis) in the direction of the plus direction of the X-axis in the longitudinal direction of the light strip 142 decreases.

At the output area 142c are several prisms, similar to the first prisms described above 14x (please refer 7 ), in the transverse direction (Z-axis direction (first direction)) of the light bar 142 educated. On the surface, the output surface 142c the light bar 142 are opposite, are several prisms, similar to the fourth prisms described above 14u (please refer 5 ), in the longitudinal direction (X-axis direction) of the light bar 142 educated.

It became the plane lighting device 50 described according to the second embodiment. Similar to the planar lighting device 10 According to the first embodiment, the planar lighting device 50 According to the second embodiment, the light distribution and luminance distribution are easily controlled.

First Modification of Second Embodiment

23 FIG. 14 is a view for explaining a first modification of the second embodiment. FIG. The plane lighting device 50 According to the second embodiment, instead of in 22 shown light bar 142 one in 23 illustrated light bar 143 include. This embodiment will be described as a first modification of the second embodiment. The light bar 143 has an output surface 143c which is a flat surface. The light bar 143 has a first part 143a and a second part 143b on. The first part 143a is a wedge-shaped part in which the width (dimension in the Y-axis direction) from a first end (end in the minus direction of the X-axis) in the direction of the plus direction of the X-axis in the longitudinal direction (X-axis direction) Direction) of the light bar 143 decreases. The second part 143b is, in a sectional view along the XY plane, a rectangular part and is with the first part 143a connected.

At the output area 143c are several prisms, similar to the first prisms described above 14x (please refer 7 ), in the transverse direction (Z-axis direction (first direction)) of the light bar 143 educated. On the surface, the output surface 143c the light bar 143 are opposite, are several prisms, similar to the fourth prisms described above 14u (please refer 5 ), in the longitudinal direction (X-axis direction) of the light bar 143 educated.

Second Modification of Second Embodiment

24 Fig. 13 is a view for explaining a second modification of the second embodiment. The plane lighting device 50 According to the second embodiment, instead of in 22 shown light bar 142 one in 24 illustrated light bar 144 include. This embodiment will be described as a second modification of the second embodiment. The light bar 144 has an output surface 144d which is a flat surface. The light bar 144 has a wedge-shaped part, in which the width (dimension in the Y-axis direction) from a first end (end in the minus direction of the X-axis) in the direction of plus of the X-axis in the longitudinal direction (X-axis direction) of the light bar 144 decreases.

At the output area 144a are several prisms, similar to the first prisms described above 14x (please refer 7 ), in the transverse direction (Z-axis direction (first direction)) of the light bar 144 educated. On the surface, the output surface 144a the light bar 144 are opposite, are several prisms, similar to the fourth prisms described above 14u (please refer 5 ), in the longitudinal direction (X-axis direction) of the light bar 144 educated.

Although the embodiments and the modifications have been described, the above-described embodiments and the modifications are not intended to limit the present invention. Aspects which are achieved by suitably combining the components described above are also included in the present invention. Other beneficial effects and modifications can be readily deduced by those skilled in the art. Accordingly, broader aspects of the present invention are not limited to the above-described embodiments and modifications, and various changes can be made.

LIST OF REFERENCE NUMBERS

10, 50

planar lighting device

11

housing frame

12a, 12b

FPC

13a, 13b

LED (light source)

14, 140, 141, 142, 143, 144

light bar

14a, 14b

Light entry surface

14c, 140d, 141c, 142c, 143c, 144a

output surface

14d

surface

15

prism plate

15a

an area

15b

surface

16

Light guide plate

16a

output surface

16b

Main area (area)

16c

Light entry surface

17

horizontal direction

18

vertical direction

19

movement direction

20

linear light source

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2015179603 [0003]

Claims (6)

A planar lighting device comprising: a light bar having an output surface which outputs light entering thereto and having a plurality of first prisms formed in a first direction on the output surface; a light source that emits light that enters the light bar; a light guide plate that guides light entering through a light entrance surface onto an output surface; and a prism plate disposed between the output surface of the light strip and the light entrance surface of the light guide plate and having a plurality of second prisms formed in a second direction intersecting the first direction on a surface facing the output surface of the light strip. Level lighting device after Claim 1 wherein a plurality of the light sources are disposed on both sides of the light bar, the second prisms each having a first area extending from a face away from the face opposite to the one face of the prism sheet, with respect to a face End in the direction of the center of the prism plate in the second direction, and a second region, which, with respect to the surface, in a direction towards the surface inclines, wherein the second region is connected to the first region, a Inclination angle, with respect to the area, of the first area of the second prism formed in a middle part of the one surface in the second direction is smaller than an inclination angle with respect to the area of the first area that is at a End portion of the one surface is formed in the second direction, and the shape of the second prism formed in the central part, with respect to a line segment, the dur The center of one surface in the second direction and parallel to a third direction intersecting the first direction and the second direction is line symmetric. Level lighting device after Claim 1 or 2 wherein the shape of the second prism is line symmetric with respect to a line segment passing through the center of the one surface in the second direction and parallel to a third direction intersecting the first direction and the second direction. Level lighting device according to one of Claims 1 to 3 wherein a plurality of convex lenses on a surface opposite to the one surface of the prism sheet are provided side by side in the second direction. Level lighting device according to one of Claims 1 to 4 wherein a plurality of third prisms are formed side by side in a third direction intersecting the first direction and the second direction on a surface opposite to the output surface of the lightguide plate, the third prisms each having a third region in which an angle with respect to the output surface of the light guide plate is equal to or greater than 0 degrees and equal to or less than 4 degrees, and having a fourth region, the fourth region being connected to the third region. Level lighting device according to one of Claims 1 to 5 , wherein a plurality of fourth prisms in the second direction are formed side by side on a surface opposite to the output surface of the light strip, the fourth prisms each having a fifth region extending in relation to the output surface of the light strip Direction extends away from the output surface of the light bar from one end toward the center light bar in the second direction, and a sixth region, which, with respect to the output surface of the light bar, in a direction towards the output surface of the light bar tends the sixth region is connected to the fifth region, and an angle formed between the sixth region of the fourth prism in the middle of the light strip and the surface opposite to the one surface of the prism plate is larger than an angle between the sixth area of the fourth prism at the end of the light bar and the area of the one fl is surface of prism plate opposite formed.

Images