JP2019153566A - Planar lighting device and manufacturing method of planar lighting device - Google Patents

Abstract

To provide a planar lighting device capable of improving assemblability, and to provide a manufacturing method of the planar lighting device.SOLUTION: A surface lighting device 10 includes a light guide plate 16, a plurality of light sources 14, and a strip-shaped fixing member 21. The light guide plate 16 emits light which has entered from a side surface 16a from one main surface out of two main surfaces 16b, 16c. The plurality of light sources 14 oppose to the side surface 16a and are arrayed along the longer direction of the side surface 16a with an interval, and each of them has a light emitting element 14a for emitting the light which enters the side surface 16a. The fixing member 21 is arranged between the light guide plate 16 and another member 22, and fixes the light guide plate 16 to the other member 22. The fixing member 21 adheres to a plurality of regions located frontward between adjacent two light sources of different combinations out of the light guide plate 16 and located with an interval along the array direction of the plurality of light sources 14.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a planar illumination device and a method for manufacturing the planar illumination device.

  There is a planar illumination device in which a top view type LED (Light Emitting Diode) and a side view type LED are arranged so as to face a light incident surface of a light guide plate. In recent years, with the demand for narrow frame lighting devices, it is necessary to narrow the fixing member for fixing the light guide plate to another member (for example, a frame, a substrate, a frame, or another fixing member bonded to the substrate). It has been.

JP-A-2006-139559

  However, as the fixing member for fixing the light guide plate to another member becomes narrower, it becomes more difficult to handle the fixing member, and there is room for improvement in terms of assembly workability.

  This invention is made | formed in view of the above, Comprising: It aims at providing the manufacturing method of the planar illuminating device which can improve assembly workability | operativity, and a planar illuminating device.

  In order to solve the above-described problems and achieve the object, a planar illumination device according to one embodiment of the present invention includes a light guide plate, a plurality of light sources, and a strip-shaped fixing member. The light guide plate emits light incident from the side surface from one main surface of the two main surfaces. The plurality of light sources have a light emitting surface that emits light incident on the side surface, facing the side surface and arranged at intervals along the longitudinal direction of the side surface. The fixing member is disposed between the light guide plate and the other member, and fixes the light guide plate to the other member. The fixing member is bonded to a plurality of regions located in front of two adjacent light sources of different combinations in the light guide plate and spaced apart along the arrangement direction of the plurality of light sources.

  According to one embodiment of the present invention, it is possible to provide a planar lighting device and a method for manufacturing the planar lighting device that can improve assembly workability.

FIG. 1 is a plan view showing an example of the appearance of the planar lighting device according to the embodiment. FIG. 2 is a diagram illustrating an example of a cross section taken along line AA in FIG. 1. FIG. 3 is a diagram illustrating an example of the configuration of the fixing member according to the embodiment. FIG. 4 is a diagram illustrating a relationship among the LED, the light guide plate, and the fixing member in the planar lighting device according to the embodiment. Drawing 5 is a figure (1) showing an example of a method of welding a fixing member to a light guide plate concerning an embodiment. FIG. 6 is a diagram (2) illustrating an example of a method of welding a fixing member to the light guide plate according to the embodiment. FIG. 7 is a diagram (3) illustrating an example of a method of welding a fixing member to the light guide plate according to the embodiment. FIG. 8 is a diagram illustrating an example of a method for welding a fixing member to a light guide plate using an ultrasonic welding apparatus different from the ultrasonic welding apparatus illustrated in FIG. 6. FIG. 9 is a diagram illustrating another configuration example of the fixing member according to the embodiment. FIG. 10 is a diagram illustrating another example of a cross section taken along the line AA of FIG. FIG. 11 is a diagram illustrating an example of a method of welding the fixing member illustrated in FIG. 9 to the frame and the light guide plate according to the embodiment. FIG. 12 is a diagram illustrating another example of a cross section taken along the line AA in FIG. 1. FIG. 13 is a diagram illustrating a relationship among LEDs, a light guide plate, and a fixing member in the planar lighting device illustrated in FIG. 12. FIG. 14 is a diagram (1) illustrating an example of a method of fixing the FPC and the light guide plate according to the embodiment using a fixing member. FIG. 15 is a diagram (2) illustrating an example of a method of fixing the FPC and the light guide plate according to the embodiment using a fixing member.

  Hereinafter, a planar illumination device and a method for manufacturing the planar illumination device according to the embodiment will be described with reference to the drawings. The application of the planar lighting device and the method for manufacturing the planar lighting device is not limited by the embodiments described below. It should be noted that the drawings are schematic, and the relationship between the dimensions of each element, the ratio of each element, and the like may differ from the actual situation. Furthermore, there are cases in which parts having different dimensional relationships and ratios are included between the drawings. In addition, for easy understanding, each drawing may illustrate a three-dimensional orthogonal coordinate system including a Z-axis in which a vertical upward direction is a positive direction and a vertical downward direction is a negative direction.

<Outline of planar lighting device>
First, the outline | summary of the planar illuminating device 10 is demonstrated using FIG. FIG. 1 is a plan view illustrating an example of an appearance of a planar lighting device 10 according to the embodiment. As shown in FIG. 1, the planar illumination device 10 according to the embodiment emits light from an effective area 40 that is an emission region that is not covered with the light shielding sheet 30. That is, the effective area 40 is defined by the light shielding sheet 30.

  The planar illumination device 10 according to the embodiment is used as a backlight of a liquid crystal display device. Such a liquid crystal display device is used for a smart phone, for example.

  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 an FPC (Flexible Printed Circuit) 12 or an LED 14 described later, while the left light shielding sheet 30 includes an FPC 12 or an LED 14 described later. This is to cover a relatively wide area. The width of the left light shielding sheet 30 is, for example, 2.5 mm or less.

<Detailed configuration of planar lighting device>
Next, a detailed configuration of the planar illumination device 10 will be described with reference to FIG. FIG. 2 is a diagram illustrating an example of a cross section taken along line AA in FIG. 1. As shown in FIG. 2, the planar illumination device 10 includes a frame 11, an FPC 12, a fixing member 13, a plurality of LEDs 14, a connection member 15, a light guide plate 16, a diffusion sheet 17, and a prism sheet 18. The reflection sheet 19, the fixing member 20, the fixing member 21, the fixing member 22, and the light shielding sheet 30 are included. In the example shown in FIG. 2, solder for connecting the FPC 12 and the LED 14 is not shown.

  The frame 11 includes an FPC 12, a fixing member 13, a plurality of LEDs 14, a connection member 15, a light guide plate 16, a diffusion sheet 17, a prism sheet 18, a reflection sheet 19, a fixing member 20, and a fixing member 21. And a member for housing the fixing member 22. The frame 11 is a sheet metal frame made of, for example, stainless steel having high rigidity. The frame 11 has a bottom part 11a and a side wall part 11b.

  The bottom portion 11a is a portion that extends along a main surface 16c, which will be described later, of the light guide plate 16. The bottom 11a has a floor surface 11c. The floor surface 11 c supports the LED 14 and the light guide plate 16 via the connection member 15 and the fixing members 21 and 22. The side wall part 11b is a part that rises integrally from the bottom part 11a in the direction in which light is emitted from the light guide plate 16 (the normal direction of the floor surface 11c) along the longitudinal direction of a side surface 16a described later of the light guide plate 16. . The side wall portion 11b has a side surface 11d.

  The FPC 12 has two main surfaces 12a and 12b, and is a substrate on which a plurality of LEDs 14 are mounted on one main surface 12a. A predetermined wiring pattern (not shown) is formed on the FPC 12, and power from an external power source (not shown) is supplied to the LED 14 through the wiring pattern, and the LED 14 can emit light. Note that the FPC 12 is an example of a substrate, and may be a rigid substrate.

  The fixing member 13 is a member that fixes the FPC 12 to the side surface 11 d of the frame 11. The fixing member 13 is, for example, a double-sided tape. Then, one surface of the fixing member 13 is attached to the main surface 12b opposite to the main surface 12a of the FPC 12, and the other surface is attached to the side surface 11d, whereby the FPC 12 is fixed to the side surface 11d. The

  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 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.

  A plurality of LEDs 14 are provided. The plurality of LEDs 14 are arranged along the long side direction (Y-axis direction) of the side surface 16 a with the light emitting surface 14 a facing the side surface 16 a of the light guide plate 16. The plurality of LEDs 14 emit light toward the side surface 16a. As described above, the plurality of LEDs 14 emit light incident on the side surface 16a.

  The connecting member 15 is, for example, a strip-shaped single-sided tape having an adhesive surface on one side. The connection member 15 includes, for example, a base material and an adhesive layer. The base material of the connection member 15 is, for example, PET (Polyethylene Terephthalate). The adhesive layer of the connection member 15 is, for example, silicon or acrylic, and is adhered to at least a part of the surface of the LED 14 on the floor surface 11c side. Note that the connecting member 15 is not limited to a single-sided tape, and may be, for example, a double-sided tape.

  The light guide plate 16 is formed in a flat plate shape using a transparent material (for example, polycarbonate resin). The light guide plate 16 has a side surface 16a and two main surfaces 16b and 16c on its outer surface.

  The side surface 16 a is an incident surface on which light emitted from the LED 14 is incident from the light emitting surface 14 a of the LED 14. The main surface 16b is an emission surface from which light incident from the side surface 16a is emitted outward. Furthermore, on the main surface 16c, which is the surface opposite to the main surface 16b, for example, an optical path changing pattern composed of a plurality of dots is formed.

  By forming such an optical path changing pattern, the traveling direction of light traveling through the light guide plate 16 is changed, and light is efficiently emitted from the main surface 16b. That is, the planar illumination device 10 according to the embodiment is a so-called edge light type illumination device.

  The diffusion sheet 17 is disposed on the main surface 16b side of the light guide plate 16, and diffuses light emitted from the main surface 16b. Explaining with a specific example, the diffusion sheet 17 is disposed so as to cover at least a part of the main surface 16b and the surface of the LED 14 opposite to the floor surface 11c, and diffuses the light emitted from the main surface 16b. .

  The prism sheet 18 is disposed on the opposite side of the light guide plate 16 with respect to the diffusion sheet 17, performs light distribution control of light diffused by the diffusion sheet 17, 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 18 on the side wall portion 11b side, and shields light emitted from a part of the main surface 16b of the light guide plate 16 to thereby provide planar illumination. An effective area 40 (see FIG. 1) from which light is emitted from the device 10 is defined.

  The reflection sheet 19 reflects light leaking from the main surface 16 c opposite to the main surface 16 b (outgoing surface) of the light guide plate 16 and returns it to the light guide plate 16 again. The reflection sheet 19 is disposed between the main surface 16 c of the light guide plate 16 and the floor surface 11 c while being fixed on the floor surface 11 c of the frame 11 by the fixing member 20.

  The fixing member 20 is, for example, a white double-sided tape, and one surface is attached to a part of the reflection sheet 19 and the other surface is attached to the fixing member 22. Thereby, the reflection sheet 19 is fixed on the floor surface 11 c via the fixing member 20 and the fixing member 22.

  The fixing member 21 is a strip-shaped fixing member, is disposed between the light guide plate 16 and the fixing member 22 (an example of another member), and is bonded to the light guide plate 16 and the fixing member 22. In the fixing member 21, one surface 21 a facing the fixing member 22 is a flat surface, and the other surface 21 b facing the main surface 16 c of the light guide plate 16 is also a flat surface. FIG. 3 is a diagram illustrating an example of the configuration of the fixing member 21 according to the embodiment.

  The fixing member 21 includes a heat activation member that is activated at a low temperature (for example, 80 degrees to 100 degrees). For example, the fixing member 21 is a heat activated double-sided adhesive tape or an elastomer. The heat-active double-sided adhesive tape is, for example, a heat-active double-sided adhesive film composed of a low-temperature active pressure-sensitive adhesive without a base material, a tape formed by applying a low-temperature active pressure-sensitive adhesive to polyurethane-coated paper or polyethylene-coated paper, Or it is the tape comprised by apply | coating a low temperature active adhesive to the acrylic nonwoven fabric. The elastomer is, for example, a thermosetting elastomer (for example, a thermosetting resin-based elastomer) or a thermoplastic elastomer.

  The fixing member 21 is more suitable as the adhesive strength per unit area is higher. The thermally activated double-sided adhesive tape can have a higher adhesive strength per unit area than the elastomer, and it is preferable to use a thermally active double-sided adhesive tape as the fixing member 21.

  The fixing member 22 shown in FIG. 2 is, for example, a single-sided tape having an adhesive layer on one side. For example, a base material and an adhesion layer are included. The base material of the fixing member 22 is, for example, PET. The adhesive layer of the fixing member 22 is, for example, silicon or acrylic. Note that the fixing member 22 is not limited to a single-sided tape, and may be, for example, a double-sided tape.

  The fixing member 22 has a larger area than the fixing member 21, and one surface 22 a is bonded to the floor surface 11 c of the frame 11. The fixing member 21 has one surface 21a welded to an end portion of the other surface 22b of the fixing member 22 on the LED 14 side, and a plurality of regions 16d (see FIG. 4), which will be described later, of the light guide plate 16 of the other surface 21b. A plurality of regions 21 c (see FIG. 7) facing each other are welded to a plurality of regions 16 d of the light guide plate 16. Each surface 21a, 21b, 22a, 22b is a flat surface.

  As shown in FIG. 2, the light guide plate 16 is fixed to the frame 11 by the fixing members 21 and 22 independently of the LEDs 14. Therefore, it is possible to remove the unit on the light guide plate 16 side (for example, the unit including the reflection sheet 19, the fixing member 20, and the fixing members 21 and 22) without removing the LED 14. Thereby, the rework which replaces | exchanges the unit containing the light-guide plate 16 can be performed easily.

  FIG. 4 is a diagram illustrating a relationship among the LED 14, the light guide plate 16, and the fixing member 21 in the planar lighting device 10 according to the embodiment. As shown in FIG. 4, the fixing member 21 is disposed to face the region 16f near the LED 14 of the light guide plate 16, and a part of the region facing the region 16f is welded.

  Specifically, the fixing member 21 is positioned in front of two adjacent LEDs 14 of different combinations in the light guide plate 16 (X-axis positive direction) and in the arrangement direction of the plurality of LEDs 14 (Y-axis direction). It is welded and fixed to a plurality of regions 16d positioned at intervals along the same. The fixing member 21 is welded to the plurality of regions 16d by ultrasonic welding.

  Thus, since the fixing member 21 is welded to the light guide plate 16, the adhesive strength to the light guide plate 16 can be increased as compared with the fixing using the conventional adhesive fixing member. Therefore, even if the region 16d used for fixing to the frame 11 of the light guide plate 16 becomes smaller as the frame becomes narrower, the necessary adhesive strength can be ensured.

  Moreover, since the fixing member 21 is not welded in the region 16e located between the regions 16d to be welded among the regions 16f in the main surface 16c of the light guide plate 16, an air layer is formed between the fixing member 21 and the plurality of regions 16e. Exists. Therefore, it is possible to avoid the fixing member 21 from affecting the progress of the light emitted from the light emitting surface 14a of the LED 14.

  Further, since the fixing member 22 is connected to the frame 11 not by welding but by adhesion, the adhesive strength per unit area between the frame 11 and the fixing member 22 is a unit between the light guide plate 16 and the fixing member 21. Low compared to the adhesive strength per area. Therefore, the light guide plate 16 in a state where the fixing member 21 is welded can be removed from the frame 11, and the unit including the light guide plate 16 can be replaced without removing the LED 14. In addition, since the fixing member 22 has a large area and is bonded to the floor surface 11c of the frame 11 with the entire one surface 22a, the bonding strength between the fixing member 22 and the frame 11 is secured.

  Here, a method for welding the fixing member 21 to the light guide plate 16 will be described as a method for manufacturing the planar lighting device 10 according to the embodiment. 5-7 is a figure which shows an example of the method of welding the fixing member 21 to the light-guide plate 16 which concerns on embodiment.

  As shown in FIG. 5, the fixing member 21, the fixing member 22, and the release paper 27 are sequentially arranged on the main surface 16 c of the light guide plate 16. At this time, the fixing member 21 is in a state of facing the main surface 16 c of the light guide plate 16. The release paper 27 is detachably attached to the adhesive layer formed on the one surface 22a of the fixing member 22.

  Next, as shown in FIG. 6, the light guide plate 16 in a state where the fixing member 21 is placed on the main surface 16 c is disposed on the flat surface 51 c of the anvil 51 of the ultrasonic welding device 50. Thereafter, the horn 52 of the ultrasonic welding device 50 is pressed onto the release paper 27 to vibrate the horn 52 ultrasonically. In the example shown in FIG. 6, the horn 52 is a comb-like member, and is a rectangular parallelepiped base portion 52 a and a plurality of rectangular parallelepiped teeth portions provided below the base portion 52 a and spaced apart from each other. 52b.

  Each of the plurality of tooth portions 52b is arranged directly below the corresponding region 16d among the plurality of regions 16d (see FIG. 4). Therefore, as shown in FIG. 7, the plurality of regions 21 c facing the plurality of regions 16 d of the fixing member 21 are activated by ultrasonic vibration and are welded to the plurality of regions 16 d of the main surface 16 c of the light guide plate 16. . Further, among the one surface 21 a of the fixing member 21, a plurality of regions 21 d positioned above the plurality of regions 21 c in FIG. 7 are activated and welded to the fixing member 22.

  As described above, the ultrasonic welding apparatus 50 having the anvil 51 and the horn 52 can execute a welding process in which the fixing member 21 is ultrasonically welded to the plurality of regions 16 d of the light guide plate 16. Since the fixing member 21 is welded to the main surface 16c of the light guide plate 16, the adhesive strength can be improved as compared with the case where an adhesive fixing member is bonded to the main surface 16c of the light guide plate 16. Therefore, the region 16d to which the fixing member 21 is bonded can be narrowed, and the frame can be further narrowed compared to the case where an adhesive fixing member is bonded to the main surface 16c of the light guide plate 16. . In addition, the fixing member 21 is formed in a strip shape and is not separated corresponding to each region 16d, and is formed as a continuous body, and therefore, handling is easy. Therefore, the assembly workability of the planar lighting device 10 can be improved. Needless to say, the fixing member 21 may be divided into a plurality of parts along the longitudinal direction of the side surface 16 a of the light guide plate 16.

  Further, since the plurality of regions 21 d of the fixing member 21 are welded to the fixing member 22, the adhesive strength between the fixing member 21 and the fixing member 22 can be improved. The one surface 22a of the fixing member 22 has a larger area than the one surface 21a of the fixing member 21, and the entire one surface 22a is bonded to the floor surface 11c of the frame 11, so that the light guide plate 16 and the frame Adhesive strength with 11 can be ensured. Moreover, since the fixing member 22 is adhered to the floor surface 11c by an adhesive material, it can be removed relatively easily.

  In the example described above, the horn 52 is formed in a comb shape and the anvil 51 is formed in a rectangular parallelepiped shape. However, the shapes of the horn 52 and the anvil 51 are not limited to the example illustrated in FIG. FIG. 8 is a diagram illustrating an example of a method for welding the fixing member 21 to the light guide plate 16 using an ultrasonic welding apparatus 50 different from the ultrasonic welding apparatus 50 illustrated in FIG. 6.

  The anvil 51 of the ultrasonic welding apparatus 50 shown in FIG. 8 is formed in a comb-like shape, and has a rectangular parallelepiped base portion 51a and a plurality of rectangular parallelepiped shapes that protrude from the base portion 51a and are spaced from each other. And a teeth portion 51b. A horn 52 shown in FIG. 8 is a rectangular member having a flat surface 52 c, and the flat surface 52 c faces the anvil 51.

  On the tooth portion 51b of the anvil 51, the release paper 27, the fixing member 22, the fixing member 21, and the light guide plate 16 are sequentially stacked. Then, the flat surface 52c of the horn 52 of the ultrasonic welding apparatus 50 is pressed on the main surface 16b of the light guide plate 16, and the horn 52 is ultrasonically vibrated.

  Thereby, the area | region pinched | interposed into each teeth part 51b of the anvil 51 and the flat surface 52c of the horn 52 among the fixing members 21 is activated by ultrasonic vibration. Therefore, similarly to the example shown in FIG. 6, the plurality of regions 21 c (see FIG. 7) located above each of the plurality of tooth portions 51 b of the fixing member 21 are welded to the plurality of regions 16 d of the light guide plate 16. Is done. In addition, a plurality of regions 21 d (see FIG. 7) located above each of the plurality of tooth portions 51 b in the fixing member 21 are activated by ultrasonic vibration and are welded to the fixing member 22.

  In the case of the ultrasonic welding apparatus 50 shown in FIG. 8, the shape of the horn 52 vibrated ultrasonically is a simple shape. Therefore, a cheaper horn 52 can be used as compared with the case where the horn 52 has a comb shape, and the manufacturing cost of the planar lighting device 10 can be suppressed.

  Further, the fixing member 21 is not limited to the configuration described above. FIG. 9 is a diagram illustrating another configuration example of the fixing member 21 according to the embodiment. FIG. 10 is a view showing another example of a cross section taken along the line AA of FIG. 1, and shows an example in the case of a configuration using the fixing member 21 shown in FIG.

  The fixing member 21 shown in FIGS. 9 and 10 is a strip-shaped fixing member. The fixing member 21 is a strip-shaped member in which one surface 21a is a flat surface and a plurality of projecting portions 21e are formed on the other surface 21b at intervals in the arrangement direction of the LEDs 14 (Y-axis direction). .

  In the example shown in FIG. 10, the fixing member 21 includes a first connection member 23 in which one surface 23 a is welded to the floor surface 11 c of the frame 11 and one surface on the other surface 23 b of the first connection member 23. 24a is welded to each other, and includes a plurality of second connection members 24 arranged at intervals in the arrangement direction (Y-axis direction) of the LEDs 14. The plurality of protrusions 21 e are formed by the plurality of second connection members 24. The other surface 21 b of the fixing member 21 described above is constituted by a part of the other surface 23 b of the first connection member 23 and the other surface 24 b of the second connection member 24.

  The first connecting member 23 is a thermally activated connecting member that is activated at a low temperature (for example, 80 degrees to 100 degrees). For example, the first connection member 23 is a thermosetting elastomer (for example, a thermosetting resin-based elastomer) or a thermoplastic elastomer. One surface 23 a of the first connection member 23 is welded to the floor surface 11 c of the frame 11.

  The second connection member 24 is a thermally activated member that is activated at a low temperature (for example, 80 to 100 degrees), and is, for example, a thermally activated double-sided adhesive tape. The heat-active double-sided adhesive tape is, for example, a heat-active double-sided adhesive film composed of a low-temperature active pressure-sensitive adhesive without a base material, a tape formed by applying a low-temperature active pressure-sensitive adhesive to polyurethane-coated paper or polyethylene-coated paper, For example, a tape composed of an acrylic nonwoven fabric coated with a low-temperature active adhesive. The other surface 24 b of the second connection member 24 is welded to the main surface 16 c of the light guide plate 16.

  FIG. 11 is a diagram illustrating an example of a method of welding the fixing member 21 illustrated in FIG. 9 to the frame 11 and the light guide plate 16 according to the embodiment. As shown in FIG. 11, the flat surface 52 c of the horn 52 is placed on the flat surface 51 c of the anvil 51 of the ultrasonic welding apparatus 50 in the state where the frame 11, the fixing member 21, and the light guide plate 16 are sequentially disposed. 16 and the horn 52 is ultrasonically vibrated.

  As a result, the first connection member 23 is welded to the floor surface 11c of the frame 11 by activating a plurality of regions located below the plurality of second connection members 24 in the one surface 23a. Further, the other surface 24 b of each second connection member 24 is activated and welded to the main surface 16 c of the light guide plate 16. Since the fixing member 21 is formed in a strip shape and is not separated corresponding to each region 16d, it is easy to handle. Therefore, in the planar lighting device 10, the assembly workability can be improved.

  When the first connecting member 23 is made of elastomer, the first connecting member 23 welded to the frame 11 can be easily detached from the frame 11 as compared with the case where the first connecting member 23 is a thermally activated double-sided adhesive tape. . Therefore, for example, the unit (including the fixing member 21) including the light guide plate 16 can be easily removed from the planar lighting device 10 by rework.

  In the example shown in FIG. 11, both the horn 52 and the anvil 51 have simple shapes, so that an inexpensive ultrasonic welding apparatus can be used as compared with the case where the horn 52 or the anvil 51 is comb-shaped. The manufacturing cost of the illumination device 10 can be reduced. In the case where the fixing member 21 shown in FIG. 9 is welded to the light guide plate 16 and the frame 11, one of the horn 52 or the anvil 51 may have a comb shape. In this case, the tooth portion 51b or the tooth portion 52b is arranged at a position that coincides with the second connecting member 24 in the vertical direction.

  Further, in the fixing member 21 shown in FIGS. 9 and 10, the plurality of second connection members 24 are arranged on the other surface 23b of the first connection member 23, but the present invention is not limited to this example. For example, the fixing member 21 may have a configuration in which a second connection member 24 having the same shape as the first connection member 23 is stacked on the other surface 23b of the first connection member 23 in plan view. In this case, the fixing member 21 is welded to the light guide plate 16 and the frame 11 using the ultrasonic welding apparatus 50 shown in FIG. Also by this, similarly to the fixing member 21 shown in FIGS. 9 and 10, the unit (including the fixing member 21) including the fixing member 21 can be easily detached from the planar lighting device 10 during rework.

  In the example described above, the planar illumination device 10 is configured using a top-view type LED, but may be configured using a side-view type LED. FIG. 12 is a diagram showing another example of a cross section taken along the line AA in FIG. 1, and an example in which the planar illumination device 10 shown in FIG. 1 has a configuration using a side-view type LED. Show. FIG. 13 is a diagram showing a relationship among the LED 14, the light guide plate 16, and the fixing member 21 in the planar illumination device 10 shown in FIG. Note that components having the same functions as those of the planar illumination device 10 shown in FIG. 2 are denoted by the same reference numerals, description thereof is omitted, and different points from the planar illumination device 10 shown in FIG.

  A planar illumination device 10 shown in FIG. 12 includes a so-called side view type LED 14 in which a light emitting surface 14 a and a mounting surface on the FPC 12 are orthogonal to each other, and a part of the main surface 12 a of the FPC 12 faces the light guide plate 16. The FPC 12 is disposed at the position. The light guide plate 16 is fixed to the main surface 12a of the FPC 12 by the fixing member 21 in a state where the optical axis of the LED 14 and the optical axis of the light guide plate 16 are aligned. The LED 14 is mounted on one main surface 12 a of the FPC 12 by solder 26.

  As shown in FIGS. 12 and 13, the fixing member 21 is fixed to a part of the region 16 f near the LED 14 in the main surface 16 c of the light guide plate 16. Specifically, the fixing member 21 is positioned in front of two adjacent LEDs 14 of different combinations in the light guide plate 16 (X-axis positive direction) and in the arrangement direction of the plurality of LEDs 14 (Y-axis direction). It is welded and fixed to a plurality of regions 16d positioned at intervals along the same. The fixing member 21 is welded to the plurality of regions 16d by ultrasonic welding. In addition, the area | region of the light-guide plate 16 to which the fixing member 21 is fixed is not limited to the main surface 16c. For example, the FPC 12 may be disposed on the emission surface (main surface 16b) side. In this case, the fixing member 21 is fixed to the main surface 16b, for example.

  Thus, since the fixing member 21 is welded to the light guide plate 16 and the FPC 12, respectively, the adhesive strength to the light guide plate 16 and the FPC 12 can be increased. Therefore, even if the region 16d used for fixing to the FPC 12 in the light guide plate 16 becomes smaller as the frame becomes narrower, the necessary adhesive strength can be ensured. Moreover, since the fixing member 21 is not welded in the region 16e located between the regions 16d, the fixing member 21 can be prevented from affecting the progress of the light emitted from the light emitting surface 14a of the LED 14.

  Here, as a method for manufacturing the planar lighting device 10 shown in FIGS. 12 and 13, a method of fixing the FPC 12 and the light guide plate 16 using the fixing member 21 will be described. 14 and 15 are diagrams illustrating an example of a method for fixing the FPC 12 and the light guide plate 16 according to the embodiment using the fixing member 21. FIG.

  As shown in FIG. 14, the fixing member 21 is disposed between the main surface 12 a of the FPC 12 and the main surface 16 c of the light guide plate 16. When the fixing member 21 has the configuration shown in FIG. 9, the first connecting member 23 of the fixing member 21 faces the main surface 12 a of the FPC 12, and the second connecting member 24 of the fixing member 21 is the light guide plate 16. It is in a state of facing the main surface 16c.

  Next, as shown in FIG. 15, the main surface 16 b of the light guide plate 16 on which the FPC 12 is disposed upward via the fixing member 21 is disposed on the flat surface 51 c of the anvil 51. Then, the horn 52 is pressed on the main surface 12b of the FPC 12, and the horn 52 is ultrasonically vibrated. Each of the plurality of tooth portions 52b provided in the horn 52 is disposed immediately below the corresponding region 16d among the plurality of regions 16d (see FIG. 13).

  Therefore, as shown in FIG. 15, the plurality of regions facing the plurality of regions 16 d (see FIG. 13) of the fixing member 21 are activated by the ultrasonic vibration to become the plurality of regions 16 d on the main surface 16 c of the light guide plate 16. Welded. In addition, a plurality of regions located below each of the plurality of tooth portions 52 b in the fixing member 21 are activated by ultrasonic vibration and are welded to the FPC 12. Note that the ultrasonic welding apparatus is not limited to the configuration shown in FIG. 15, and may have the configuration shown in FIG. 8.

  Thus, since the fixing members 21 are welded to the light guide plate 16 and the FPC 12, respectively, the adhesive strength can be improved as compared with the case where the adhesive fixing members are bonded to the light guide plate 16 and the FPC 12, respectively. . Therefore, the region 16d of the light guide plate 16 used for fixing the light guide plate 16 to the FPC 12 can be narrowed, and compared with the case where an adhesive fixing member is bonded to the main surface 16c of the light guide plate 16. A narrow frame can be achieved.

  Further, when the fixing member 21 has the configuration shown in FIG. 9 and the first connecting member 23 is made of elastomer, the first connecting member 23 is welded to the FPC 12 as compared with the case where the first connecting member 23 is a thermally activated double-sided adhesive tape. It is easy to remove the first connecting member 23 from the FPC 12. Therefore, for example, the unit (including the fixing member 21) including the light guide plate 16 can be easily removed from the planar lighting device 10 by rework. The fixing member 21 may have a configuration in which a second connection member 24 having the same shape as the first connection member 23 is overlapped on the other surface 23b of the first connection member 23 in plan view. In this case, the first connecting member 23 can be made of elastomer, and the second connecting member 24 can be a heat activated double-sided adhesive tape. That is, the fixing member 21 includes two layers having different adhesive strengths per unit area, and a layer on the light guide plate 16 side (a layer facing the light guide plate 16) of the two layers is a layer on the FPC 12 side (with the FPC 12). The structure may be such that the adhesive strength per unit area is greater than that of the facing layer. Also in this case, the unit (including the fixing member 21) including the light guide plate 16 can be easily detached from the planar illumination device 10 by rework.

  In addition, the manufacturing method of the planar lighting device 10 using the side-view type LED may not include a welding step of welding the fixing member 21 to the FPC 12 as illustrated in FIG. For example, the fixing member 21 welds the fixing member 21 to which the fixing member 22 and the release paper 27 are attached to the light guide plate 16 as shown in FIG. 6 or FIG. Then, the release paper 27 is peeled off and one surface 22 a of the fixing member 22 is bonded to the FPC 12.

  In the example shown in FIG. 6, the light guide plate 16, the fixing member 21, the fixing member 22, and the release paper 27 are placed on the anvil 51 in this order, and the horn 52 is pressed against the release paper 27. Not. For example, the release paper 27, the fixing member 22, the fixing member 21, and the light guide plate 16 may be placed on the anvil 51 in this order, and the horn 52 may be pressed against the light guide plate 16 to perform ultrasonic welding. That is, the order of the light guide plate 16, the fixing member 21, the fixing member 22, and the release paper 27 arranged on the anvil 51 may be reverse to the order shown in FIG. The same applies to the ultrasonic welding apparatus 50 shown in FIG.

  Further, in the example shown in FIG. 11, the frame 11, the fixing member 21, and the light guide plate 16 are placed in this order on the flat surface 51 c of the anvil 51 and the horn 52 is pressed against the light guide plate 16. . For example, the light guide plate 16, the fixing member 21, and the frame 11 may be placed on the anvil 51 in this order, and the horn 52 may be pressed against the frame 11 to perform ultrasonic welding.

  Similarly, in the example illustrated in FIG. 15, the light guide plate 16, the fixing member 21, and the FPC 12 are placed in this order on the flat surface 51 c of the anvil 51, and the horn 52 is pressed against the FPC 12. However, the example is not limited thereto. For example, the FPC 12, the fixing member 21, and the light guide plate 16 may be placed on the anvil 51 in this order, and the horn 52 may be pressed against the light guide plate 16 to perform ultrasonic welding.

  As described above, the planar lighting device 10 according to the embodiment is disposed between the light guide plate 16 and another member (for example, the fixing member 22, the frame 11, or the FPC 12), and the light guide plate 16 is connected to the other member. A strip-shaped fixing member 21 is provided. The plurality of fixing members 21 are respectively positioned in front of two adjacent LEDs 14 of different combinations in the light guide plate 16 and are spaced along the arrangement direction (Y-axis direction) of the plurality of LEDs 14. It adheres to the region 16d. In such a planar lighting device 10, the fixing member 21 is formed in a strip shape, and is formed as a continuous body that is not separated corresponding to each region 16d. Therefore, in the planar lighting device 10, the assembly workability can be improved. Moreover, since the fixing member 21 is adhered to the light guide plate 16 by welding, the adhesive strength to the light guide plate 16 can be increased, and further narrowing of the frame can be realized. The fixing member 21 is not limited to the shape shown in FIGS. 3 and 9, and may have a shape other than the shape shown in FIGS. 3 and 9 as long as it is formed in a strip shape. For example, the one surface 21a of the fixing member 21 may have an uneven surface or a meandering surface. Further, for example, there may be unevenness or a meandering curve on the end side of the fixing member 21. As described above, the fixing member 21 may have a shape including a strip-shaped portion capable of integrally covering the plurality of regions 16d. For example, at least one of the one surface 21a, the other surface 21b, and the end side may be used. A shape having a protruding portion, an uneven surface, or a serpentine surface may be used.

  In addition, although the fixing member 21 mentioned above was set as the structure containing the heat activation member activated at low temperature (for example, 80 to 100 degree | times), the structure containing the heat activation member activated at less than 80 degree | times or more than 100 degree | times. It may be.

  Moreover, although the fixing member 21 shown in FIG. 9 is comprised with the 1st connection member 23 and the 2nd connection member 24 which are different from each other, the fixing member 21 is a plurality of protrusions 21e with one type of member. It can also be formed in a strip shape having.

  In the above-described embodiment, the fixing member 21 is configured to include a heat activation member, and the heat activation member is activated by ultrasonic vibration to weld the fixing member 21 to the light guide plate 16. It is not limited to. That is, the fixing member 21 only needs to increase the adhesive strength to the light guide plate 16 and may be configured not to include the heat activation member. Further, the bonding of the fixing member 21 to the light guide plate 16 is not limited to ultrasonic welding, and may be, for example, laser welding or may be performed by vibration other than ultrasonic vibration.

  In addition, the bonding step of bonding the fixing member 21 to the plurality of regions 16 d of the light guide plate 16 and the fixing member 22 is performed by replacing the ultrasonic welding with the plurality of regions 16 d of the light guide plate 16 and the fixing member 22. It may be one that is thermocompression-bonded. In this case, assuming that the direction orthogonal to the one surface 21a and the other surface 21b of the fixing member 21 is the vertical direction, the thermocompression bonding device (not shown) applies each region 21c, 21d while applying pressure in the vertical direction. The fixing member 21 is bonded to the plurality of regions 16d and the fixing member 22 by heating the regions 21c and 21d.

  For example, the light guide plate 16, the fixing member 21, the fixing member 22, and the release paper 27 in the state shown in FIG. 5 are placed on the stage of the thermocompression bonding apparatus so that the light guide plate 16 faces down. In the thermocompression bonding apparatus, the fixing member 21 is heated to a plurality of regions of the light guide plate 16 by applying pressure to the region facing the region 16d (region excluding the plurality of regions 16e) in the vertical direction of the release paper 27. 16d and the fixing member 22 can be bonded. Also by this, adhesive strength can be improved. In addition, the mounting surface of the light guide plate 16 on the stage of the thermocompression bonding apparatus can be heated. In this case, for example, the stage of the thermocompression bonding apparatus can be configured to heat a region of the light guide plate 16 that opposes each region 16d (region excluding the plurality of regions 16e) in the vertical direction.

  When the fixing member 21 is an adhesive elastomer, the fixing member 21 may be bonded to the plurality of regions 16d of the light guide plate 16 and the fixing member 22 without applying heat, instead of thermocompression bonding. In this case, assuming that the direction orthogonal to the one surface 21a and the other surface 21b of the fixing member 21 is the vertical direction, the crimping device (not shown) applies pressure in the vertical direction to the regions 21c and 21d, The fixing member 21 is bonded to the plurality of regions 16 d and the fixing member 22. Also by this, adhesive strength can be improved.

  Moreover, although LED14 was demonstrated as an example of a light source in embodiment mentioned above, a light source is not limited to LED14, Other point-like light sources may be sufficient.

  Further, the present invention is not limited by the above embodiment. What comprised suitably combining each component mentioned above 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.

  DESCRIPTION OF SYMBOLS 10 Planar illuminating device, 12 FPC (an example of another member), 14 LED (an example of a light source), 16 Light guide plate, 16a Side surface, 16b, 16c Main surface, 21 Fixing member, 22 Fixed member (An example of another member) ), 23 1st connecting member, 24 2nd connecting member

Claims (14)

A light guide plate that emits light incident from the side surface from one of the two main surfaces;
A plurality of light sources having a light emitting surface that emits light that is incident on the side surface and is arranged along the longitudinal direction of the side surface, facing the side surface;
A strip-shaped fixing member that is disposed between the light guide plate and the other member and fixes the light guide plate to the other member;
The fixing member is
A planar illumination device that is bonded to a plurality of regions that are respectively positioned in front of two light sources adjacent to each other in different combinations in the light guide plate and that are spaced along the arrangement direction of the plurality of light sources. The fixing member is
The surface facing the light guide plate is a flat surface,
The planar illumination device according to claim 1, wherein a plurality of regions located at intervals along the arrangement direction of the plurality of light sources in the flat surface are bonded to the plurality of regions of the light guide plate. In the fixing member,
A plurality of protrusions are formed at intervals in the arrangement direction,
The planar lighting device according to claim 1, wherein the plurality of protrusions are bonded to the plurality of regions, respectively. The fixing member is
A first connecting member having one surface bonded to the other member;
A plurality of second connection members that are adhered to the other surface of the first connection member and arranged at intervals in the arrangement direction;
The planar lighting device according to claim 3, wherein the plurality of protrusions are formed by the plurality of second connection members. A substrate on which a surface opposite to the light emitting surface of the light source is mounted on one main surface;
A frame that houses the light guide plate, the light source, and the substrate;
The fixing member is
The planar illumination device according to any one of claims 1 to 4, wherein the light guide plate is fixed using the frame or a fixing member bonded to the frame as the other member. A substrate partially facing the light guide plate, on which the plurality of light sources are arranged,
The fixing member is
The planar illumination device according to any one of claims 1 to 4, wherein the light guide plate is fixed using the substrate as the other member. The fixing member is
The planar shape according to claim 6, comprising two layers having different adhesive strength per unit area, wherein the light guide plate side layer has a higher adhesive strength per unit area than the substrate side layer. Lighting device. The fixing member is
The planar illumination device according to claim 1, wherein the planar illumination device is disposed between the other main surface of the light guide plate and the other member. The fixing member is
The planar illumination device according to claim 1, wherein the planar illumination device is disposed between the one main surface of the light guide plate and the other member. It is a manufacturing method of the planar lighting device according to any one of claims 1 to 9,
The manufacturing method of a planar illuminating device including the adhesion | attachment process of adhere | attaching the said fixing member on these areas of the said light-guide plate. The method for manufacturing a planar lighting device according to claim 10, wherein in the bonding step, the fixing member is bonded to the plurality of regions of the light guide plate by welding.   The method for manufacturing a planar lighting device according to claim 11, wherein in the bonding step, the comb-shaped member is ultrasonically vibrated to ultrasonically weld the fixing member to the plurality of regions.   In the bonding step, in a state where the light guide plate and the fixing member are disposed between a comb-shaped member and a member having a flat surface, the member having the flat surface is ultrasonically vibrated into the plurality of regions. The manufacturing method of the planar illuminating device of Claim 11 which ultrasonically welds the said fixing member. The manufacturing method of the planar lighting device according to claim 10, wherein in the bonding step, the fixing member is bonded to the plurality of regions of the light guide plate by pressure bonding.

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