JP2018006322A - Planar lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planar lighting device satisfying a request on thinning, and further having an excellent luminance characteristic.SOLUTION: A planar lighting device includes: a light guide plate configured to emit light made incident from a side surface; a light source arranged on the side surface side, and having a light-emitting surface configured to emit light made incident into the side surface; a substrate that has two main surfaces, and on which a surface opposite to the light-emitting surface of the light source is mounted; a frame having a side surface and a floor surface, and storing the light guide plate, the light source and the substrate; and a first coupling member arranged between the light guide plate and the light source and the floor surface, and coupling the light guide plate and the light source.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a planar lighting device.

  There is a planar illumination device in which a top view type LED (Light Emitting Diode) is disposed so as to face a light incident surface of a light guide plate.

JP 2002-156632 A

  In recent years, the thickness of the light guide plate has become relatively small with respect to the thickness of the LED in accordance with the demand for thinning the planar lighting device. For this reason, improvement in the alignment accuracy of the optical axis between the light guide plate and the LED is important in stabilizing the luminance characteristics such as luminance and luminance distribution at a high level.

  The present invention has been made in view of the above, and an object of the present invention is to provide a planar lighting device having excellent luminance characteristics while meeting the demand for thinning.

  In order to solve the above-described problems and achieve the object, the planar illumination device according to one aspect of the present invention is disposed on the side surface side with a light guide plate that emits light incident from the side surface from the output surface, A light source having a light emitting surface that emits light incident on the side surface, a substrate having two main surfaces, the surface opposite to the light emitting surface of the light source being mounted on one main surface, and a side surface And a frame that houses the light guide plate, the light source, and the substrate, and is disposed between the light guide plate, the light source, and the floor surface, and connects the light guide plate and the light source. 1 connecting member.

  According to one embodiment of the present invention, excellent luminance characteristics can be obtained while meeting the demand for thinning.

FIG. 1 is a front view illustrating an example of the appearance of the planar illumination device according to the embodiment. 2 is a cross-sectional view taken along line AA in FIG. Drawing 3 is a figure for explaining an example of an assembly method of a field lighting device concerning an embodiment. FIG. 4 is a diagram for explaining a planar illumination device according to a first modification of the embodiment. FIG. 5 is a diagram for explaining a planar illumination device according to a second modification of the embodiment. FIG. 6 is a diagram for explaining a planar illumination device according to a third modification of the embodiment. FIG. 7 is a diagram for explaining a planar illumination device according to a fourth modification of the embodiment. FIG. 8 is a diagram for explaining a planar illumination device according to a fifth modification of the embodiment. FIG. 9 is a diagram for explaining a planar illumination device according to a sixth modification of the embodiment.

  Hereinafter, a planar illumination device according to an embodiment will be described with reference to the drawings. In addition, the relationship of the dimension of each element in a drawing, the ratio of each element, etc. may differ from reality. Even between the drawings, there are cases in which portions having different dimensional relationships and ratios are included.

(Embodiment)
FIG. 1 is a front view illustrating an example of the appearance of the planar illumination device according to the embodiment. As shown in the example of FIG. 1, the planar illumination device 10 according to the embodiment emits light from an emission region (also referred to as an effective area) 90 that is not covered with the light shielding sheet 30. That is, the effective area 90 is defined by the light shielding sheet 30. The planar illumination device 10 according to the present embodiment is used as a backlight of a liquid crystal display device. Such a liquid crystal display device is used, for example, in a smartphone.

  In FIG. 1, the left light shielding sheet 30 is wider than the right light shielding sheet 30. This is because the right light shielding sheet 30 covers a relatively narrow area that does not include LEDs 14 and FPC (Flexible Printed Circuits) 12 described later, and the left light shielding sheet 30 relatively includes LEDs 14 and FPC 12 described later. This is to cover a wide area. The width of the left light shielding sheet 30 is, for example, 1.5 mm. Further, in FIG. 1, illustration of a light shielding sheet 31 described later is omitted.

  2 is a cross-sectional view taken along line AA in FIG. As shown in FIG. 2, the planar lighting device 10 includes an FPC 12, a fixing member 13, an LED 14, a first connection member 15, a light guide plate 16, a second connection member 17, a diffusion sheet 18, a prism sheet 19, a frame 20, and a reflection. The sheet 21, the light shielding sheet 30, and the light shielding sheet 31 are included.

  The frame 20 houses the FPC 12, the fixing member 13, the LED 14, the first connecting member 15, the light guide plate 16, the second connecting member 17, the diffusion sheet 18 and the prism sheet 19. The frame 20 is a sheet metal frame made of, for example, stainless steel having high rigidity. The frame 20 has a side wall portion 20a and a bottom portion 20b.

  The bottom portion 20b is a portion that extends along a main surface 16b, which will be described later, of the light guide plate 16. The bottom portion 20b has a floor surface 20d. The floor surface 20d has a flat surface 20d_1 and a concave surface 20d_2 of a concave portion 20c described later. The light guide plate 16 and the LEDs 14 are placed on the plane 20d_1. The side wall portion 20a is a portion that integrally rises in the direction in which light is emitted from the bottom portion 20b (the normal direction of the flat surface 20d_1 of the floor surface 20d) along the long side of a light incident side surface 16c described later of the light guide plate 16. The side wall portion 20a has a side surface 20e. Moreover, the bottom part 20b has the recessed part 20c. The recess 20c is a member that escapes the lower end portion of the FPC 12 that is formed to be recessed in the direction opposite to the direction in which light is emitted along the side surface 20e from the side surface 20e side portion of the floor surface 20d. The width of the recess 20c is narrow so that the larger first connecting member 15 is disposed on the flat surface 20d_1 of the floor surface 20d. The recess 20c has a concave surface 20d_2. In the present embodiment, the recess 20c is not an essential component. Therefore, for example, the bottom 20b may be flat without having the recess 20c.

  The light guide plate 16 is formed in a rectangular shape in a top view using a transparent material (for example, polycarbonate resin). The light guide plate 16 has two main surfaces 16 a and 16 b and a light incident side surface (light incident surface) 16 c which is a side surface on the side where the LED 14 is disposed on the outer surface thereof. The light emitted from the LED 14 is incident on the light incident side surface 16c. Of the two main surfaces 16a and 16b, one main surface 16a is an output surface from which light incident from the light incident side surface 16c (light emitted from the LED 14) is emitted. Therefore, in the following description, “main surface 16a” may be referred to as “exit surface 16a”. Note that the emission surface is also referred to as a light emitting surface because it is a surface from which light is emitted. On the main surface (main surface other than the main surface 16a out of the two main surfaces) 16b side that is the surface opposite to the exit surface 16a of the light guide plate 16, for example, an optical path changing pattern composed of a plurality of dots is provided. Is formed. By forming the optical path changing pattern, the traveling direction of the light traveling in the light guide plate 16 is changed, and light is emitted from the emission surface 16a. That is, the planar illumination device 10 according to the embodiment is a so-called edge light type illumination device.

  The reflection sheet 21 reflects the light leaked from the main surface 16b opposite to the emission surface 16a and returns it to the light guide plate 16 again. The reflection sheet 21 is disposed between the main surface 16b of the light guide plate 16 and the floor surface 20d in a state of being fixed on the floor surface 20d (specifically, the flat surface 20d_1 of the floor surface 20d) by the double-sided tape 22. .

  The double-sided tape 22 is, for example, a white double-sided tape, one surface is affixed to a part of the reflection sheet 21, and the other surface is affixed to the floor surface 20d (specifically, the flat surface 20d_1 of the floor surface 20d). Attached. Thereby, the double-sided tape 22 fixes the reflective sheet 21 on the floor surface 20d.

  The LED 14 is a point light source (point light source). The LED 14 is, for example, a pseudo white LED composed of a blue LED and a yellow phosphor. The LED 14 is a so-called top view type LED that is formed in a substantially rectangular parallelepiped shape as a whole and has a light emitting surface 14 a on a surface opposite to a surface mounted on the FPC 12. In the present embodiment, a plurality of LEDs 14 are provided, and the plurality of LEDs 14 are predetermined along the long side direction of the light incident side surface 16 c with the light emitting surface 14 a facing the light incident side surface 16 c of the light guide plate 16. Are arranged at intervals (or in close contact). The plurality of LEDs 14 emit light toward the light incident side surface 16c. Thus, the plurality of LEDs 14 emit light that is incident on the light incident side surface 16c.

  The FPC 12 has two main surfaces 12a and 12b, and is a substrate on which the surface opposite to the light emitting surface 14a of the LED 14 is mounted on one main surface 12a on the LED 14 side. Power from a power source (not shown) is supplied to the LED 14 via the FPC 12, and the LED 14 is turned on.

  The fixing member 13 fixes the FPC 12 to the side surface 20 e of the frame 20. The fixing member 13 is, for example, a double-sided tape, and one surface is affixed to the main surface 12b opposite to the main surface 12a of the FPC 12, and the other surface is affixed to the side surface 20e. On the other hand, the FPC 12 is fixed.

  The first connecting member 15 is disposed between the light guide plate 16 and the LED 14 and the floor surface 20d (specifically, the flat surface 20d_1 of the floor surface 20d), and optically or structurally connects the light guide plate 16 and the LED 14. . Explaining with a specific example, the first connecting member 15 connects the light incident side surface 16c of the light guide plate 16 and the light emitting surface 14a of the LED 14 with the optical axis of the light guide plate 16 and the optical axis of the LED 14 aligned. Connect. The first connecting member 15 is a strip-like single-sided tape whose major axis is the direction in which the LEDs 14 are arranged, and includes an adhesive layer (adhesive) 15a and a base material 15b. In addition, the 1st connection member 15 is not restricted to the single-sided tape formed from the adhesion layer 15a and the base material 15b, For example, the double-sided tape affixed on the main surface at the side of LED14 of the base material 15b and the base material 15b. The single-sided tape formed from may be sufficient.

  The base material 15b is, for example, PET, and the adhesive layer 15a is, for example, silicon or acrylic. The adhesive layer 15a adheres to at least a part of the main surface 16b of the light guide plate 16 near the LED 14 and also adheres to at least a part of the surface of the LED 14 near the light guide plate 16 near the light guide plate 16. Thereby, at least a part of the main surface 16 b of the light guide plate 16 and at least a part of the surface of the LED 14 on the floor surface 20 d side are attached to the first connecting member 15. As a result, the first connecting member 15 connects the light incident side surface 16 c of the light guide plate 16 and the light emitting surface 14 a of the LED 14.

  Since the 1st connection member 15 which concerns on this embodiment is a single-sided tape, the light-guide plate 16 and LED14 are not fixed with respect to the floor surface 20d. For this reason, even if some force is applied to the planar illumination device 10 from the outside, the light guide plate 16 and the LED 14 can release the external force. For this reason, according to the planar illuminating device 10 which concerns on this embodiment, generation | occurrence | production of the damage of the light-guide plate 16 and LED14 can be suppressed.

  The first connecting member 15 has a member that absorbs light or a member that reflects light. For example, when the first connecting member 15 has a member that reflects light, the light emitted from the light emitting surface 14a of the LED 14 is reflected and returned to the light guide plate 16 again, so that the luminance can be improved. .

  In addition, even if the thickness of the LED 14 and the thickness of the light guide plate 16 are different, for example, the thickness of the light guide plate 16 is thicker than the thickness of the LED 14, the LED 14 can be obtained by using the first connecting member 15. The LED 14 and the light guide plate 16 can be connected with the surface of the floor surface 20d and the main surface 16b of the light guide plate 16 being flush with each other. Therefore, according to the embodiment, the light coupling efficiency between the LED 14 and the light guide plate 16 can be stabilized by using the first connecting member 15.

  The 2nd connection member 17 is arrange | positioned on the opposite side to the 1st connection member 15 with respect to the light-guide plate 16 and LED14, and connects the light-guide plate 16 and LED14 optically or structurally. To explain with a specific example, the light incident side surface 16c of the light guide plate 16 and the light emitting surface 14a of the LED 14 are connected. The 2nd connection member 17 is arrange | positioned between the diffusion sheet 18 mentioned later, the light-guide plate 16, and LED14. The second connecting member 17 is a double-sided tape, and one surface is affixed to at least a part of the light exiting surface 16a of the light guide plate 16 near the LED 14 and the surface of the LED 14 opposite to the floor surface 20d is guided. Affixed to at least a part near the light plate 16. Thereby, at least a part of the main surface 16a of the light guide plate 16 and at least a part of the surface opposite to the floor surface 20d of the LED 14 are attached to the second connecting member 17. As a result, the second connecting member 17 connects the light incident side surface 16 c of the light guide plate 16 and the light emitting surface 14 a of the LED 14.

  Further, the other surface of the second connecting member 17 is attached to at least a part of the diffusion sheet 18 on the side wall portion 20a side. Thereby, the 2nd connection member 17 fixes the diffusion sheet 18 to the light-guide plate 16 and LED14. Accordingly, since the second connecting member 17 can suppress the diffusion sheet 18 from floating from the light guide plate 16, it suppresses deterioration of luminance characteristics such as luminance and luminance distribution of light emitted from the effective area 90. can do.

  The diffusion sheet 18 is disposed on the emission surface 16a side of the light guide plate 16, and diffuses light emitted from the emission surface 16a. Explaining with a specific example, the diffusion sheet 18 is disposed so as to cover at least a part of the light exit surface 16a and the surface of the LED 14 opposite to the floor surface 20d, and diffuses the light emitted from the light output surface 16a. . As described above, the diffusion sheet 18 is fixed to the light guide plate 16 and the LED 14 by the second connecting member 17.

  The prism sheet 19 is disposed on the opposite side of the light guide plate 16 with respect to the diffusion sheet 18, performs light distribution control of light diffused by the diffusion sheet 18, and emits light subjected to light distribution control.

  The light shielding sheet 30 is disposed so as to cover a part of the prism sheet 19 on the side wall portion 20a side, and shields light emitted from a part of the light emitting surface 16a of the light guide plate 16, thereby providing a planar illumination device. An effective area 90 where light is emitted from 10 is defined.

  For example, the light shielding sheet 30 is a single-sided tape that can shield light, and a portion on one end side is attached to the outer surface of the side wall portion 20 a of the frame 20. The surface on the prism sheet 19 side of the portion on the other end side of the light shielding sheet 30 is attached to a part of the prism sheet 19 on the side wall 20a side.

  The light shielding sheet 31 is a double-sided tape capable of shielding light. Of the two surfaces of the light shielding sheet 31, one surface is adhered to the other end portion of the light shielding sheet 30, and the other surface is adhered to a liquid crystal display device using the planar illumination device 10 as a backlight. It is done.

  Next, a method for assembling the planar lighting device 10 will be described with reference to FIG. FIG. 3 is a diagram for explaining an example of an assembly method of the planar lighting device 10 according to the embodiment.

  As shown in the example of FIG. 3, in step 1, first, the LED 14 is mounted on the main surface 12 a of the FPC 12. Next, the 1st connection member 15 is attached to at least one part of the surface by the side of the floor surface 20d of LED14. Then, the main surface 12 b of the FPC 12 is fixed to the side surface 20 e of the frame 20 using the fixing member 13. For example, the first connecting member 15 is placed on the flat surface 20d_1 of the floor surface 20d, and the FPC 12 and the LED 14 are moved toward the side surface 20e so that the first connecting member 15 slides on the flat surface 20d_1 of the floor surface 20d. The main surface 12 b is fixed to the side surface 20 e using the fixing member 13. According to the present embodiment, the first connecting member 15 is thus placed on the flat surface 20d_1 of the floor surface 20d, and the FPC 12 and the LED 14 are side-mounted so that the first connecting member 15 slides on the flat surface 20d_1 of the floor surface 20d. The main surface 12b can be fixed to the side surface 20e using the fixing member 13 by a simple method of moving toward 20e.

  In Step 1, after fixing the main surface 12b of the FPC 12 to the side surface 20e using the fixing member 13, the surface on the base material 15b side of the first connecting member 15 that is a single-sided tape is bonded to the floor surface 20d by an adhesive. You may fix to it. Thereby, even if some force is applied to the planar illumination device 10 from the outside, the LED 14 and the light guide plate 16 are fixed to the frame 20, so that the movement of the LED 14 and the light guide plate 16 is suppressed. . As a result, it is suppressed that the LED 14 and the light guide plate 16 are in contact with other members, the optical axis of the light guide plate 16 is deviated from the optical axis of the LED 14, and the interval between the LED 14 and the light guide plate 16 is widened. The Therefore, according to the embodiment, breakage of the LED 14 and the light guide plate 16 and changes in optical characteristics can be suppressed.

  In step 2, the optical axis of the light guide plate 16 (for example, the center in the thickness direction of the light guide plate 16) and the LED 14 are set with the floor surface 20d (specifically, the plane 20d_1 of the floor surface 20d) as the alignment reference in the thickness direction. Alignment with the optical axis (for example, the center in the thickness direction of the LED 14) is performed, and at least a part of the main surface 16b of the light guide plate 16 is attached to the first connecting member 15 in a state where the two optical axes coincide. Thereby, the optical axis of the light guide plate 16 and the optical axis of the LED 40 coincide, and the light guide plate 16 is fixed to the LED 14 in a state where the light incident side surface 16 c of the light guide plate 16 and the light emitting surface 14 a of the LED 14 are connected. . Therefore, according to the planar illumination device 10 according to the present embodiment, the alignment accuracy of the optical axis between the light guide plate 16 and the LED 14 is improved. Therefore, according to the planar illumination device 10 according to the present embodiment, it is possible to stabilize luminance characteristics such as luminance and luminance distribution at a high level. Moreover, according to the planar lighting device 10 according to the present embodiment, the first connecting member 15 that connects the light guide plate 16 and the LED 14 is thin, so that it is possible to meet the demand for thinning. From the above, according to the planar illumination device 10 according to the present embodiment, it is possible to have excellent luminance characteristics while meeting the demand for thinning.

  In addition, when the thickness of the LED 14 and the thickness of the light guide plate 16 are different (particularly when the thickness of the LED 14 is smaller than the thickness of the light guide plate 16), in step 2, the LED 14 and the surface on the floor surface 20d side are guided. The optical surface of the light guide plate 16 and the optical axis of the LED 14 may be aligned with the main surface 16b of the light plate 16 being flush with each other. The same applies when the thickness of the LED 14 and the thickness of the light guide plate 16 match.

  In Step 2, when the light guide plate 16 is attached to the first connecting member 15, the reflective sheet 21 is fixed on the floor surface 20d (specifically, the flat surface 20d_1 of the floor surface 20d) by using the double-sided tape 22. May be.

  In Step 1 and Step 2, the case where the LED 14 and the light guide plate 16 are connected by the first connecting member 15 after the FPC 12 mounted with the LED 14 is fixed to the side surface 20e by the fixing member 13 has been described. The present embodiment is not limited to this. For example, after connecting the LED 14 mounted on the FPC 12 and the light guide plate 16 using the first connecting member 15, the main surface 12 b of the FPC 12 may be fixed to the side surface 20 e using the fixing member 13.

  In step 3, one surface of the second connecting member 17, which is a double-sided tape, is attached to at least a part of the light exiting surface 16 a of the light guide plate 16 near the LED 14, and the surface of the LED 14 on the side opposite to the floor surface 20 d is provided. Affixed to at least part of the light guide plate 16. As a result, the second connecting member 17 can connect the light incident side surface 16 c of the light guide plate 16 and the light emitting surface 14 a of the LED 14.

  In step 4, the other surface of the second connecting member 17 is attached to at least a part of the diffusion sheet 18 on the side wall 20a side.

  In step 5, the prism sheet 19 is disposed on the opposite side of the light guide plate 16 with respect to the diffusion sheet 18. In step 5, a portion on one end side of the light shielding sheet 30, which is a single-sided tape, is attached to the outer surface of the side wall portion 20 a of the frame 20. In step 5, the surface on the prism sheet 19 side of the portion on the other end side of the light shielding sheet 30 is attached to a part of the prism sheet 19 on the side wall 20 a side. In step 5, one of the two surfaces of the light shielding sheet 31 that is a double-sided tape is attached to a portion on the other end side of the light shielding sheet 30.

  The planar lighting device 10 according to the present embodiment has been described above. As described above, according to the planar illumination device 10 according to the present embodiment, it is possible to have excellent luminance characteristics while meeting the demand for thinning.

(First Modification, Second Modification of Embodiment)
In the above-described embodiment, the case where the first connecting member 15 includes a member that absorbs light or a member that reflects light has been described. However, the first connecting member 15 may be a member that transmits light. Then, two embodiment in case the 1st connection member 15 is a member which permeate | transmits light is described as the 1st modification and 2nd modification of embodiment. In the description of the first modification and the second modification, the same components as those of the above-described embodiment may be denoted by the same reference numerals and description thereof may be omitted.

  FIG. 4 is a diagram for explaining a planar illumination device 10a according to a first modification of the embodiment, and FIG. 5 explains a planar illumination device 10b according to a second modification of the embodiment. FIG. In the case where the first connecting member 15 is a member that transmits light, as shown in FIG. 4, the above-described reflection sheet 21 is connected to the first connecting member 15 and the floor surface 20d (specifically, the floor surface 20d). The reflection sheet 21 may be disposed so as to extend to the plane 20 d 1) so that the light transmitted through the first connecting member 15 is reflected and returned to the light guide plate 16 again. Thereby, according to the planar illuminating device 10a which concerns on a 1st modification, a brightness | luminance can be improved.

  Further, instead of arranging the reflection sheet 21 so as to extend between the first connecting member 15 and the floor surface 20d, as shown in FIG. 5, a reflection sheet 25 different from the reflection sheet 21 is connected to the first connection member. You may arrange | position between the member 15 and the floor surface 20d (specifically plane 20d_1 of the floor surface 20d). With this configuration, the luminance can be improved also in the planar illumination device 10b according to the second modification.

(Third Modification of Embodiment)
Next, a third modification of the embodiment will be described. In the description of the third modification, the same components as those in the above-described embodiment may be denoted by the same reference numerals and description thereof may be omitted.

  FIG. 6 is a diagram for explaining a planar illumination device according to a third modification of the embodiment. As shown in FIG. 6, the 1st connection member 15 is provided only in the area | region except the front of LED14, ie, a light-projection direction. Therefore, an air layer exists between the main surface 16b (see FIG. 2) of the light guide plate 16 and the floor surface 20d (specifically, the plane 20d_1 (see FIG. 2) of the floor surface 20d) in front of each LED 14. Therefore, the light that is emitted in front of the LED 14, enters the light incident side surface 16c, and reaches the main surface 16b enters the first connecting member 15 (adhesive layer 15a) with a large transmittance. Instead, the light is guided into the light guide plate 16 by normal reflection at the boundary between the light guide plate 16 and air. Therefore, according to the planar illumination device according to the third modification, the luminance can be improved.

  In the third modification, the example in which the first connecting member 15 is provided only in the region excluding the light emitting direction of the LED 14 has been described. However, the adhesive layer 15a excludes the light emitting direction of the LED 14. It is provided only in the region, and the base material 15b may have the same shape as that of the first embodiment, that is, a strip shape.

(Fourth Modification of Embodiment)
In the embodiment described above, the case where there is one adhesive layer 15a has been described. However, the adhesive layer 15a may be divided into an adhesive layer attached to the light guide plate 16 and an adhesive layer attached to the LED 14. . Therefore, such an embodiment will be described as a fourth modification of the embodiment. In the description of the fourth modification, the same components as those in the above-described embodiment may be denoted by the same reference numerals and description thereof may be omitted.

  FIG. 7 is a diagram for explaining a planar illumination device according to a fourth modification of the embodiment. As shown in FIG. 7, in the planar lighting device according to the fourth modification, the first connection member 15 is provided on the base material 15 b and the base material 15 b, and is adhered to the light guide plate 16. And the 2nd adhesion layer 15a_2 provided on the base material 15b and adhere | attached on LED14 is included. With this configuration, since the thickness of the first adhesive layer 15a_1 and the second adhesive layer 15a_2 can be adjusted independently, as shown in FIG. 7, the thickness of the light guide plate 16 and the thickness of the LED 14 are different. Even if it exists, the center (optical axis) of the thickness direction of the light-guide plate 16 and LED14 can be made to correspond.

(Fifth Modification of Embodiment)
In the above-described embodiment, the example in which the first connecting member 15 is disposed on the flat surface 20d_1 of the floor surface 20d has been described. However, the first connecting member 15 has a recess 20c (specifically, a recess 20c formed on the floor surface 20d). It may be disposed on the concave surface 20d_2 of the concave portion 20c. Therefore, such an embodiment will be described as a planar illumination device according to a fifth modification of the embodiment. In the description of the fifth modification, the same components as those in the above-described embodiment may be denoted by the same reference numerals and description thereof may be omitted.

  FIG. 8 is a diagram for explaining a planar illumination device according to a fifth modification of the embodiment. In the planar lighting device 10c according to the fifth modification shown in FIG. 8, the first connecting member 15 is disposed in the concave portion 20c (specifically, on the concave surface 20d_2 of the concave portion 20c), and one The point provided with two light shielding sheets 30b and 30c instead of the light shielding sheet 30 is different from the planar illumination device 10 according to the embodiment shown in FIG. In the planar lighting device 10c shown in FIG. 8, the adhesive layer 15a is provided only in a region excluding the light emitting direction of the LED 14, and the base material 15b has the same shape as the above-described embodiment, that is, a strip shape. It is.

  As shown in FIG. 8, since the first connecting member 15 is disposed in the recess 20c (specifically, on the concave surface 20d_2 of the recess 20c), it is larger when the width of the recess 20c is relatively wide. The first connecting member 15 can be disposed in the recess 20c.

  The light shielding sheet 30 b is a single-sided tape that can block light, and a portion on one end side is attached to the outer surface of the side wall portion 20 a of the frame 20.

  The light shielding sheet 30c is a double-sided tape capable of shielding light, and the surface on one side of the prism sheet 19 is attached to the other side of the light shielding sheet 30b. Further, the surface on the prism sheet 19 side of the portion on the other end side of the light shielding sheet 30 c is attached to a part on the side wall portion 20 a side of the prism sheet 19. The surface of the light shielding sheet 30c opposite to the prism sheet 19 is attached to a liquid crystal display device that uses the planar illumination device 10 as a backlight. With this configuration, the number of light shielding sheets present on the light emission direction side of the prism sheet 19 is one, so that the number of light shielding sheets present on the light emission direction side of the prism sheet 19 is two or more. Thus, the thickness can be reduced.

(Sixth Modification of Embodiment)
In the embodiment described above, the case where the first connecting member 15 is a single-sided tape has been described. However, the first connecting member 15 may be a double-sided tape. Therefore, such an embodiment will be described as a planar illumination device according to a sixth modification of the embodiment. In the description of the sixth modification, the same components as those in the above-described embodiment may be denoted by the same reference numerals and description thereof may be omitted.

  FIG. 9 is a diagram for explaining a planar illumination device according to a sixth modification of the embodiment. As illustrated in the example of FIG. 9, the planar lighting device 10 d according to the sixth modification includes a first connecting member 32 instead of the first connecting member 15.

  The first connecting member 32 optically or structurally connects the light guide plate 16 and the LED 14. The first connecting member 32 fixes the light guide plate 16 and the LED 14 to the frame 20. The 1st connection member 32 is a double-sided tape, and contains adhesion layer 32a, 32b and the base material 32c. The adhesive layers 32a and 32b are, for example, silicon or acrylic. The base material 32c is, for example, PET.

  The adhesive layer 32a is disposed on the main surface of the base material 32c on the LED 14 side. The adhesive layer 32a adheres to at least part of the main surface 16b of the light guide plate 16 near the LED 14 and also adheres to at least part of the surface of the LED 14 near the light guide plate 16 near the light guide plate 16. Thereby, at least a part of the main surface 16 b of the light guide plate 16 and at least a part of the surface of the LED 14 on the floor surface 20 d side are attached to the first connecting member 32. As a result, the first connecting member 32 connects the light incident side surface 16 c of the light guide plate 16 and the light emitting surface 14 a of the LED 14.

  The adhesive layer 32b is disposed on the main surface of the base material 32c on the floor surface 20d side. The adhesive layer 32b adheres to the floor surface 20d. Thereby, the 1st connection member 32 fixes the light-guide plate 16 and LED14 to the floor surface 20d and the flame | frame 20 by extension.

  In the sixth modification, the LED 14 and the light guide plate 16 are moved because the LED 14 and the light guide plate 16 are fixed to the frame 20 even when some force is applied to the planar illumination device 10d from the outside. Is suppressed. As a result, it is suppressed that the LED 14 and the light guide plate 16 are in contact with other members, the optical axis of the light guide plate 16 is deviated from the optical axis of the LED 14, and the interval between the LED 14 and the light guide plate 16 is widened. The Therefore, according to the planar illumination device 10d according to the sixth modification, it is possible to suppress the breakage of the LED 14 and the light guide plate 16 and the change in optical characteristics.

  The embodiment and the first to sixth modifications have been described above. The present invention is not limited to the above embodiment. What was comprised combining each component mentioned above suitably is also contained in this invention. Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspect of the present invention is not limited to the above-described embodiment, and various modifications can be made.

10, 10a, 10b, 10c, 10d Planar illumination device 12 FPC (substrate)
13 Fixing member 14 LED (light source)
DESCRIPTION OF SYMBOLS 15, 32 1st connection member 15a, 32a, 32b Adhesive layer 15b, 32c Base material 16 Light guide plate 17 2nd connection member 18 Diffusion sheet 19 Prism sheet 20 Frame 20a Side wall part 20b Bottom part 20c Recessed part 20d Floor surface 20e Side surface 30 Light shielding sheet 31 Shading sheet

Claims (13)

A light guide plate that emits light incident from the side surface from the exit surface;
A light source having a light emitting surface arranged on the side surface and emitting light incident on the side surface;
A substrate on which a surface opposite to the light emitting surface of the light source is mounted on one main surface;
A frame having a side surface and a floor surface, housing the light guide plate, the light source, and the substrate;
A first connecting member disposed between the light guide plate and the light source and the floor, and connecting the light guide plate and the light source;
A planar lighting device.   The at least one part of the surface on the opposite side to the said output surface of the said light-guide plate and the at least one part of the said floor surface side surface of the said light source are attached to a said 1st connection member. Planar lighting device.   The planar illumination device according to claim 2, further comprising a fixing member that fixes the substrate to the side surface of the frame.   The planar lighting device according to claim 3, wherein the first connecting member is a single-sided tape, and the fixing member is a double-sided tape.   The planar lighting device according to claim 3, wherein the first connecting member and the fixing member are both double-sided tape, and the first connecting member fixes the light guide plate and the light source to the frame.   The planar illumination device according to any one of claims 1 to 5, wherein the first connecting member includes a member that absorbs light or a member that reflects light. The first connecting member is a member that transmits light,
The planar illumination according to any one of claims 1 to 5, further comprising a reflection sheet that is disposed between the first connection member and the floor surface and reflects light transmitted through the first connection member. apparatus. The first connecting member is provided in a region excluding the light emitting direction of the light source.
The planar illumination device according to any one of claims 1 to 7. The first connecting member includes a base material, and an adhesive layer that is provided on the base material and adheres to the light guide plate and the light source,
The adhesive layer is provided in a region excluding the light emitting direction of the light source.
The planar illumination device according to any one of claims 1 to 7.   The first connecting member includes a base material, a first adhesive layer that is provided on the base material and adheres to the light guide plate, and a second adhesive layer that is provided on the base material and adheres to the light source. Item 9. The planar illumination device according to any one of Items 1 to 8.   11. The apparatus according to claim 1, further comprising: a second connecting member that is disposed on the opposite side of the first light guide plate and the light source and that connects the light guide plate and the light source. The surface illumination device described in 1. A diffusion sheet that is disposed so as to cover at least a part of the surface opposite to the floor surface of the light emitting surface and the light source, and further diffuses light emitted from the light emitting surface;
The second connecting member is disposed between the diffusion sheet, the light guide plate, and the light source, and fixes the diffusion sheet to the light guide plate and the light source.
The planar illumination device according to claim 11.   The planar lighting device according to claim 11 or 12, wherein the second connecting member is a double-sided tape.

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