CN109578853B

CN109578853B - Planar lighting device

Info

Publication number: CN109578853B
Application number: CN201811113443.6A
Authority: CN
Inventors: 古田诚; 吉田隆人
Original assignee: MinebeaMitsumi Inc
Current assignee: MinebeaMitsumi Inc
Priority date: 2017-09-28
Filing date: 2018-09-25
Publication date: 2020-08-14
Anticipated expiration: 2038-09-25
Also published as: CN208832222U; CN109578853A

Abstract

The invention provides a planar lighting device capable of realizing further narrow frame. The planar lighting device of the embodiment includes a light guide plate, an LED, an FPC, and a wiring. The light guide plate emits light incident from the light incident surface. The plurality of LEDs are arranged on the light incident surface side and emit light from the light emitting surface. The FPC has a mounting surface facing a bottom surface of the LED intersecting the light emitting surface and on which the LED is mounted. The wiring is formed on the opposite surface of the FPC from the mounting surface, and connects the plurality of LEDs in series.

Description

Planar lighting device

Technical Field

The present invention relates to a planar lighting device.

Background

Conventionally, for example, there is a planar lighting device in which a plurality of leds (light Emitting diodes) are connected in parallel to a mounting surface of a substrate, and light is incident from a light incident surface of a light guide plate to be emitted (see, for example, patent document 1). In the planar lighting device, a plurality of LEDs are arranged along the longitudinal direction of a rectangular fpc (flexible Printed circuit), for example.

Patent document 1: japanese patent laid-open publication No. 2016-207279

However, in the conventional technique, wiring needs to be routed to the short side direction of the LED on the mounting surface of the FPC, and therefore the length of the FPC in the short side direction has to be made long. Therefore, in the conventional planar lighting device, there is room for improvement in that a further narrow frame is realized.

Disclosure of Invention

The present invention has been made in view of the above, and an object thereof is to provide a planar lighting device capable of further narrowing a frame.

In order to solve the above-described problems and achieve the object, a planar lighting device according to an aspect of the present invention includes a light guide plate, a plurality of light sources, a substrate, and wiring. The light guide plate emits light incident from the light incident surface. The plurality of light sources are disposed on the light incident surface side, and emit the light from a light emitting surface. The substrate has a mounting surface facing a bottom surface of the light source intersecting the light emitting surface, and the light source is mounted on the mounting surface. The wiring is formed on the opposite surface of the substrate to the mounting surface, and connects the plurality of light sources in series.

According to an aspect of the present invention, a planar lighting device capable of further narrowing a frame can be provided.

Drawings

Fig. 1 is a front view showing an example of an external appearance of a planar lighting device according to an embodiment.

Fig. 2 is a sectional view of the planar lighting device according to the embodiment.

Fig. 3A is a diagram showing a mounting surface of the FPC according to the embodiment.

Fig. 3B is a diagram showing the opposite surface of the FPC according to the embodiment.

Fig. 4 is a diagram illustrating a connector section according to an embodiment.

Fig. 5 is a diagram showing a connection unit according to the embodiment.

Fig. 6 is a diagram showing a positional relationship between the connector portion and the LED according to the embodiment.

Fig. 7 is a cross-sectional view of the FPC according to the embodiment.

Fig. 8 is a cross-sectional view of an FPC according to a modification.

Fig. 9 is a cross-sectional view of an FPC according to a modification.

Description of the reference numerals

A planar lighting device; 10, 100. A frame; an LED; a light guide plate; 14.. FPC; a prism sheet; a diffuser sheet; a first joining member; a second joining member; connecting the disc portion; a connecting portion; 22a, 22b.. guide; a reinforcement portion; an electrifying part; wiring; an external connection; 60a, 60b. A forearm portion; a posterior arm portion; a joint; 213.

Detailed Description

The planar lighting device according to the embodiment will be described below with reference to the drawings. In the drawings, the relationship between the sizes of the respective elements, the ratio of the respective elements, and the like may be different from the actual ones. The drawings may include portions having different dimensional relationships and ratios from each other. In the drawings, for ease of understanding, a three-dimensional cartesian coordinate system having the light emission direction of the planar lighting device as the positive Z-axis direction is illustrated in some cases.

Fig. 1 is a front view showing an example of an external appearance of a planar lighting device according to an embodiment. As shown in the example of fig. 1, the planar lighting device 1 according to the embodiment has a substantially rectangular shape in a plan view. One end side in the longitudinal direction (Y-axis direction) of the planar lighting device 1 is covered with a light-shielding sheet 10 including a first light-shielding sheet 10a and a second light-shielding sheet 10 b. The other end side in the longitudinal direction of the planar lighting device 1 is covered with the light-shielding sheet 100.

The planar lighting device 1 emits light from a light emitting region (also referred to as a light emitting Area) R not covered by the light-

shielding sheets

10 and 100. That is, the light-emitting region R is defined by the light-

shielding sheets

10 and 100. The planar lighting device 1 according to the present embodiment is used as a backlight of a liquid crystal display device. Such a liquid crystal display device is used in, for example, a smartphone.

In addition, as shown in fig. 1, the light-shielding sheet 10 is wider than the light-shielding sheet 100. This is due to: the light-shielding sheet 100 covers a light guide plate, a diffusion sheet, and a prism sheet, which will be described later, which are present in a lower portion of the light-shielding sheet 100 on the Z-axis negative direction side, whereas the light-shielding sheet 10 covers a relatively wide area including an led (light Emitting diode), an fpc (flexible Printed circuit), and the like, which will be described later, in addition to the light guide plate, the diffusion sheet, and the prism sheet, which will be described later, which are present in the lower portion of the light-shielding sheet 10.

Next, a cross section taken along line a-a of fig. 1 will be described with reference to fig. 2. Fig. 2 is a cross-sectional view of the planar lighting device 1 according to the embodiment. As shown in fig. 2, the planar lighting device 1 includes: the light guide plate includes a first light-shielding sheet 10a, a second light-shielding sheet 10b, a frame 11, an LED12, a light guide plate 13, an FPC14, a prism sheet 15, a diffusion sheet 16, a first coupling member 17, and a second coupling member 18.

The frame 11 has a side wall 11a and a bottom surface 11b, and is a case that houses the LED12, the light guide plate 13, the FPC14, the prism sheet 15, the diffusion sheet 16, the first coupling member 17, and the second coupling member 18.

The LED12 is, for example, a point-like light source. In the present embodiment, the LEDs 12 are arranged at predetermined intervals along the X-axis direction, which is the longitudinal direction of the FPC 14. The LED12 is, for example, a substantially white LED composed of a blue LED and a yellow phosphor.

The LED12 is formed in a substantially rectangular parallelepiped shape as a whole, and has a bottom surface 12b and

side surfaces

12a, 12c, 12d, and 12 e. The side surface 12a (light-emitting surface 12a1) is a side surface intersecting (e.g., orthogonal to) the bottom surface 12b, and is a surface from which light is emitted in the Y-axis positive direction, which is a light-emitting surface 12a1 that is a partial region toward the light guide plate 13 described later. The entire region of the side surface 12a may be the light-emitting surface 12a 1. The bottom surface 12b is a surface intersecting the light-emitting surface 12a1 (side surface 12a) and facing a mounting surface 14a of an FPC14 described later. The side surface 12c is a side surface intersecting the bottom surface 12b and is a rear surface (hereinafter, rear surface 12c) on the opposite side of the light-emitting surface 12a1 (side surface 12 a). The side surfaces 12d and 12e intersect the light-emitting surface 12a1 and the bottom surface 12b, respectively. That is, the LED12 is a side view type in which the light-emitting surface 12a1 is orthogonal to the mounting surface 14 a. The LED12 may be of a so-called top view type in which the surface on the opposite side of the light-emitting surface 12a1 faces the FPC 14. The side surface 12e is a surface to which the FPC14 is fixed together with the back surface 12c by the solder 60, but this point will be described in detail later in fig. 6. A side surface 12d (see fig. 6) opposite to the side surface 12e is also fixed by the solder 60 in the same manner.

The light guide plate 13 is formed in a rectangular shape in a plan view using a transparent material (for example, polycarbonate resin). The light guide plate 13 has two

main surfaces

13a and 13b and a side surface 13 c. The side surface 13c is a light incident surface (hereinafter, referred to as a light incident surface 13c) that faces the light emitting surface 12a1 of the LED12 and on which light from the light emitting surface 12a1 is incident. The main surface 13a is an emission surface (hereinafter, referred to as an emission surface 13a) that emits light incident from the light incident surface 13 c. The main surface 13b is an opposite surface (hereinafter, referred to as an opposite surface 13b) on the opposite side of the emission surface 13 a. An optical path changing pattern formed of, for example, a plurality of dots is formed on the opposite surface 13 b.

This changes the traveling direction of the light traveling in the light guide plate 13, and causes more light to be emitted from the emission surface 13 a. That is, the planar lighting device 1 according to the embodiment is a so-called edge-light type lighting device in which the LEDs 12 are arranged along the edge (light incident surface 13c) of the light guide plate 13.

The light guide plate 13 may be provided with a wedge portion on the side surface 13c, for example. Specifically, the light guide plate 13 may be provided with a wedge portion as a portion where the thickness of the light guide plate 13 gradually decreases from the side surface 13c toward the side surface (not shown) on the Y-axis positive direction side, which is the opposite side to the side surface 13 c.

The FPC14 is a rectangular flexible substrate extending in the X-axis direction, which is the arrangement direction of the LEDs 12. The FPC14 is an example of a substrate, and may be a hard (rigid) substrate.

The FPC14 is disposed substantially parallel to the main surface 13b of the light guide plate 13 on the bottom surface 11b side of the frame 11 and between the LED12 and the light guide plate 13 and the bottom surface 11b of the frame 11. The FPC14 has two

main faces

14a, 14 b. The main surface 14a is a mounting surface (hereinafter, referred to as a mounting surface 14a) on which the LED12 is mounted. The mounting surface 14a faces the bottom surface 12b of the LED 12. The main surface 14b is an opposite surface (hereinafter, referred to as an opposite surface 14b) opposite to the mounting surface 14 a. The FPC14 is connected to a driver circuit, not shown, and controls lighting of the LED12 by the driver circuit. The FPC14 is provided on the bottom surface 11b side of the frame 11, but may be provided on the output surface 13a side of the light guide plate 13. Specifically, the FPC14 may be disposed on the top surface side of the LED12 on the side opposite to the bottom surface 12b, that is, on the positive Z-axis direction side.

The prism sheet 15 performs light distribution control of light diffused by a diffusion sheet 16 described later, and emits light subjected to the light distribution control in the light emission direction, which is the positive Z-axis direction.

The diffusion sheet 16 is disposed on the emission surface 13a side of the light guide plate 13, and diffuses light emitted from the emission surface 13 a. Specifically, for example, the diffusion sheet 16 is disposed so as to cover the emission surface 13a, and diffuses the light emitted from the emission surface 13 a.

The first connecting member 17 and the second connecting member 18 are, for example, double-sided tapes. The first connecting member 17 optically or structurally connects the light guide plate 13 and the LED 12. Specifically, the first coupling member 17 couples the light incident surface 13c of the light guide plate 13 and the light emitting surface 12a1 of the LED 12.

The second coupling member 18 is disposed between the main surface 13b of the light guide plate 13 and the FPC14, and fixes the light guide plate 13 to the FPC 14. For example, the second coupling member 18 is attached to at least a part of the main surface 14a of the FPC14, which is close to the light guide plate 13, and to at least a part of the main surface 13b of the light guide plate 13, which is close to the LED 12.

Next, with reference to fig. 3A and 3B, FPC14 will be further described. Fig. 3A is a view showing the mounting surface 14a of the FPC 14. Fig. 3B is a diagram showing the opposite surface 14B of the FPC 14.

First, the mounting surface 14a of the FPC14 will be described with reference to fig. 3A. As shown in FIG. 3A, the mounting surface 14a is provided with a plurality of connector sections 20-1 to 20 and an external connection section 41. The connection pad portions 20-1 to 20 are electrically connected to electrode terminals (

terminals

24a and 24b described later) of the LED12, and are, for example, conductive members such as metal.

As shown in FIG. 3A, LEDs 12-1-20 are disposed on each of the plurality of pad portions 20-1-20. In other words, in fig. 3A, a total of 20 LEDs 12 are arranged on the mounting surface 14 a. The number of the LEDs 12 shown in fig. 3A is an example, and may be any number of one or more.

The plurality of pad sections 20-1 to 20 are provided with two current-carrying sections 30-1a to 20a and 30-1B to 20B electrically connected to an opposite surface 14B (see fig. 3B) opposite to the mounting surface 14a, respectively.

The conducting portions 30-1a to 20a and 30-1b to 20b are, for example, so-called blind via holes which are not formed with holes which physically penetrate the mounting surface 14a and the opposite surface 14 b. The conducting portions 30-1a to 20a and 30-1b to 20b may be other through holes such as so-called through holes, which form holes penetrating the mounting surface 14a and the opposite surface 14 b.

For example, land portion 20-1 is provided with conducting portion 30-1a electrically connected to the anode terminal of LED12-1 and conducting portion 30-1b electrically connected to the cathode terminal.

In addition, in the mounting surface 14a, the outer edges of the pad portions 20-1 to 20 are not provided with wiring for connecting the LEDs 12-1 to 20 and a cover film for covering the wiring. In other words, such wiring is provided only on the opposite surface 14 b.

Thus, since it is not necessary to provide a space for routing wiring on the mounting surface 14a as in the conventional art, the region at the outer edge of the upper and lower sides (Y-axis direction) of the connector disk sections 20-1 to 20 can be made narrow. In other words, in the planar lighting device 1 according to the embodiment, the length of the FPC14 in the Y axis direction, which is the short side direction, can be made short, and therefore, a further narrow bezel can be realized.

The external connection portion 41 is a portion for connecting the FPC14 to a driver circuit for controlling lighting of the LED 12. The external connection portion 41 is connected to the drive circuit while protecting the wiring from the opposite surface 14b to the mounting surface 14a through the hole portion.

The wiring is routed from the opposite surface 14b of the external connection portion 41 to the mounting surface 14a side, but the wiring does not necessarily need to be routed to the mounting surface 14a side, and the wiring may be provided only on the opposite surface 14b side.

The details of the land portions 20-1 to 20 and the conducting portions 30-1a to 20a and 30-1b to 20b will be described later with reference to FIGS. 4 to 6. In the following, the "land portions 20" and the "conducting portions 30 a" are generically referred to as "conducting portions 30 b" without particularly distinguishing the land portions 20-1 to 20, the conducting portions 30-1a to 20a, and the conducting portions 30-1b to 20 b.

Next, the opposite surface 14B of the FPC14 will be described with reference to fig. 3B. As shown in FIG. 3B, the wiring 40-1 to 22 and the external connection portion 41 are provided on the opposite surface 14B. The wirings 40-1 to 22 are conductive members made of metal such as copper foil, for example, and are formed with conductive patterns by etching or the like. The wirings 40-1 to 22 are protected by a cover film (not shown) made of polyimide or the like, for example.

The wiring lines 40-1, 40-11, 40-12, 40-22 in the wiring lines 40-1 to 22 are connected with wiring lines 40-1a, 40-11a, 40-12a, 40-22 a.

The wiring line 40-1a is routed on the lower side, which is the negative side of the Y axis of the wiring lines 40-2-11, thereby electrically connecting the wiring line 40-1 and the wiring line 40-12.

The wiring line 40-11a is routed on the upper side, i.e., the positive Y-axis direction side of the wiring lines 40-12 to 40-21 and is routed between the wiring lines 40-21 and 40-22, whereby the wiring line 40-11 is connected to the external connection unit 41 and is electrically connected to the drive circuit.

The wiring line 40-12a is wound on the lower side of the wiring lines 40-13 to 40-21, thereby connecting the wiring line 40-1 and the wiring line 40-12 to the external connection portion 41 and electrically connecting to the drive circuit.

The wiring line 40-22a connects the wiring line 40-22 to the external connection portion 41 by being routed on the lower side of the wiring line 40-21, and is electrically connected to the drive circuit. The wires 40-1 to 22 are electrically insulated from the wires 40-1 and 40-12.

In addition, each of the wirings 40-1 to 22 is connected to two current-carrying portions 30-1a to 20a and 30-1b to 20b except for the wirings 40-1, 40-11, 40-12 and 40-22. The LED12 disposed on the mounting surface 14a (fig. 3A) is located on the opposite surface 14B as indicated by the broken line in fig. 3B. Specifically, in FIG. 3B, 20 LEDs 12-1-20 are connected by wires 40-1-22 such that 10 LEDs are connected in series to form an LED row and the LED rows in two rows are connected in parallel.

More specifically, the LEDs 12-1 to 20 are arranged so as to span between the wirings 40-1 to 22. For example, the first LED12-1 from the right side (the positive X-axis direction side), the anode terminal (terminal 24a described later) is connected to the wiring 40-1 through the conducting portion 30-1a, and the cathode terminal (terminal 24b described later) is connected to the wiring 40-2 through the conducting portion 30-1 b. In other words, LED12-1 is disposed in a manner that spans between wiring 40-1 and wiring 40-2.

In addition, for the second LED12-2 from the right, the anode terminal is connected to the wiring 40-2 through the conducting portion 30-2a, and the cathode terminal is connected to the wiring 40-3 through the conducting portion 30-2 b. In other words, the LED12-2 is disposed in a manner that spans between the wiring 40-2 and the wiring 40-3.

In addition, with respect to the tenth LED12-10 from the right side, the anode terminal is connected to the wiring 40-10 via the conducting portion 30-10a, and the cathode terminal is connected to the wiring 40-11 via the conducting portion 30-10 b. In other words, the LEDs 12-10 are arranged in a manner that spans between the wires 40-10 and 40-11. That is, in FIG. 3B, ten LEDs 12-1 to 10 and ten LEDs 12-11 to 20 are connected in series, respectively.

Next, the connection disc portion 20 will be described in detail with reference to fig. 4. Fig. 4 is a diagram showing the connection disc portion 20. As shown in fig. 4, the connection disc portion 20 includes: a pair of connecting

portions

21a, 21b, two

guide portions

22a, 22b, and a reinforcing portion 23.

The pair of

connection portions

21a and 21b are provided with current-carrying portions 30-a and 30-b, respectively, and are electrically connected to electrode terminals (

terminals

24a and 24b described later) of the LED12 (see fig. 6). Specifically, the anode terminal of the LED12 is connected to the connection portion 21a, and the cathode terminal of the LED12 is connected to the connection portion 21 b. In addition, when the two

connection portions

21a and 21b are not particularly distinguished, they are described as "connection portion 21".

The

guide portions

22a and 22b are disposed so as to be interposed between the two connecting

portions

21a and 21 b. The

guide portions

22a and 22b are marks for checking whether or not the LED12 is attached in an appropriate position and posture when attached.

The reinforcing portion 23 is disposed so as to be interposed between the two

guide portions

22a and 22b. The reinforcing portion 23 is fixed to the LED12 by solder at the time of mounting the LED12, thereby reinforcing the mounting strength of the LED 12. This prevents the LEDs 12 from being displaced or loosened.

The

guide portions

22a and 22b and the reinforcing portion 23 are not necessarily required, and may be omitted. The number of the

guide portions

22a and 22b and the reinforcing portion 23 shown in fig. 4 is an example, and an arbitrary number may be set.

Next, the connection portion 21 will be described in detail with reference to fig. 5. Fig. 5 is a view showing the connection portion 21. As shown in fig. 5, the connection portion 21 has an コ -shaped shape in a plan view. Specifically, the connection portion 21 includes a front arm portion 210, a rear arm portion 211, and a connection portion 212.

The forearm portion 210 is provided on the light-emitting surface 12a1 (see fig. 6) side of the LED12, has a forearm length a1 indicating the length of the forearm portion 210 in the Y-axis direction, and is provided with the above-described current-carrying portion 30. The front arm 210 is formed on the light guide plate 13 (see fig. 2) side, which is the positive Y-axis direction side, with respect to a notch 213 to be described later. The rear arm portion 211 is provided on the rear surface 12c side of the LED12, and has a rear arm length a2 indicating the length of the rear arm portion 211 in the Y axis direction. Rear arm portion 211 is formed on the opposite side of front arm portion 210 with respect to notch portion 213.

As shown in fig. 5, the connecting portion 21 is not symmetrical with respect to the X axis. Specifically, the front arm length a1 of the connecting portion 21 is greater than the rear arm length a 2. In other words, the rear arm 211 is smaller in area than the front arm 210. This increases the degree of freedom in the position of forming the conducting portion 30, and facilitates the process of forming the conducting portion 30.

The coupling portion 212 couples the front arm portion 210 and the rear arm portion 211. The coupling portion 212 has a notch 213 partially cut out in a rectangular shape. The connection portion 21 is not limited to the コ shape, and may be U-shaped or V-shaped. In other words, the notch 213 may be cut in a curved shape or a V shape.

Next, the positional relationship between the connector section 20 and the LED12 when mounted will be described with reference to fig. 6. Fig. 6 is a diagram showing a positional relationship between the connector section 20 and the LED12 according to the embodiment.

As shown in fig. 6, the pair of connecting

portions

21a and 21b are provided on the side surfaces 12d and 12e connected to both ends of the LED12 in the X axis direction. The

notches

213a and 213b are provided at positions where the pair of

connection portions

21a and 21b face each other. The

cutouts

213a and 213b are provided on the rear surface 12c side of the LED12, which is the negative Y-axis direction side, and the current-carrying portions 30-a and 30-b are provided on the light-emitting surface 12a1 side, which is the positive Y-axis direction side of the LED 12. The connector section 20 is attached with the LED12 so as to overlap with some of the

regions

50a, 50b, 50c, 50d, and 50e in a plan view viewed from the positive Z-axis direction. Specifically, the LED12 covers the

notches

213a and 213b of the

connection portions

21a and 21b with predetermined regions (

regions

50a and 50 e). In other words, the

connection portions

21a, 21b have: a region not covered with a predetermined region of the LED12 in a plan view (region other than the

regions

50a and 50 e).

The

solder

60a and 60b fixes the regions of the

connection portions

21a and 21b not covered with the LED12 to the side surfaces 12d and 12e (see fig. 7) and the back surface 12c of the LED 12. That is, the land portion 20 is connected to side surfaces 12d and 12e and a back surface 12c, which are side surfaces intersecting with the bottom surface 12b of the LED 12. In other words, by having a region not covered with the LED12, solder fixation between the

connection portions

21a and 21b and the LED12 can be facilitated.

Further, by fixing the LED12 so as to cover the

notches

213a and 213b, the

solders

60a and 60b can be spread only on the

connection portions

21a and 21b, and the

solders

60a and 60b can be prevented from spreading toward the

notches

213a and 213 b. In other words, since the

solder

60a and 60b can be prevented from spreading on the bottom surface 12b (see fig. 7) of the LED12, the LED12 can be prevented from floating, and the planar lighting device 1 can be further reduced in weight and thickness.

As shown in fig. 6, the LED12 includes: and a pair of

terminals

24a, 24b provided on the side surfaces 12d, 12e, respectively. The terminal 24a is an anode terminal, and is connected to the connection portion 21a in the region 50 a. The terminal 24b is a cathode terminal, and is connected to the connection portion 21b in the region 50 e. Further, the connection portion 21a to which the terminal 24a is connected to a protruding portion 70a protruding from the side surface 12 d. Further, the connection portion 21b to which the terminal 24b is connected to a protruding portion 70b protruding from the side surface 12 e. In other words, the disk portion 20 is connected to the protruding portion 70a and the protruding portion 70 b.

Specifically, as shown in fig. 6, the side surface 12d of the LED12 is composed of three surfaces. More specifically, the side surface 12d is composed of a first surface 12d1, a second surface 12d2, and a third surface 12d 3. The first surface 12d1 is a surface on the light-emitting surface 12a1 side and extends in a direction (Y-axis direction) perpendicular to the light-emitting surface 12a 1. The second surface 12d2 is a surface continuous with the first surface 12d1 on the Y-axis negative direction side, and extends in a direction substantially parallel to the light-emitting surface 12a1 (X-axis direction). The third surface 12d3 is a surface continuous with the second surface 12d2 on the X-axis positive direction side, and extends in a direction (Y-axis direction) orthogonal to the light-emitting surface 12a 1. The third surface 12d3 is a surface continuous with the surface 12cd, which is a part of the peripheral end of the rear surface 12c, on the Y-axis negative direction side. The partial surface 12cd is a region of the rear surface 12c excluding a region overlapping the side surface 12a on the rear surface side and a partial surface 12 ce. The protrusion 70a is formed of the second surface 12d2, the third surface 12d3, and a part of the surface 12 cd. As shown in fig. 6, the terminal 24a of the LED12 has a shape of a plane view "コ" formed by three surfaces (the second surface 12d2, the third surface 12d3, and a part of the surface 12cd) constituting the protruding portion 70 a.

As shown in fig. 6, the side surface 12e of the LED12 is formed of three surfaces. Specifically, the side surface 12e is composed of a first surface 12e1, a second surface 12e2, and a third surface 12e 3. The first surface 12e1 is a surface on the light-emitting surface 12a1 side and extends in a direction (Y-axis direction) perpendicular to the light-emitting surface 12a 1. The second surface 12e2 is a surface continuous with the first surface 12e1 on the Y-axis negative direction side, and extends in a direction substantially parallel to the light-emitting surface 12a1 (X-axis direction). The third surface 12e3 is a surface continuous with the second surface 12e2 on the X-axis negative direction side, and extends in a direction (Y-axis direction) perpendicular to the light-emitting surface 12a 1. The third surface 12e3 is a surface continuous with the surface 12ce that is a part of the peripheral end of the back surface 12c on the Y-axis negative direction side. The partial surface 12ce is a region of the back surface 12c excluding a region overlapping with the side surface 12a on the back surface side and the partial surface 12cd described above. The protrusion 70b is formed of the second surface 12e2, the third surface 12e3, and a part of the surface 12 ce. As shown in fig. 6, the terminal 24b of the LED12 has a shape of "コ" in plan view, which is formed by three surfaces (the second surface 12e2, the third surface 12e3, and a part of the surface 12ce) constituting the protruding portion 70 b.

The shape of the

notches

213a and 213b matches the shape of the

terminals

24a and 24b shaped like "コ" in plan view. Accordingly, the

terminals

24a and 24b shaped like "コ" in plan view cover the

notches

213a and 213b of the

connection portions

21a and 21b, and therefore, the LED12 can be easily and accurately positioned with respect to the connector portion 20. The shape of the

notches

213a and 213b can be arbitrarily set to match the shape of the

terminals

24a and 24b, and for example, the shape of the

terminals

24a and 24b may be U-shaped or V-shaped in a plan view, in addition to the "コ" shape in a plan view.

Next, a cross section taken along line B-B of fig. 6 will be described with reference to fig. 7. Fig. 7 is a cross-sectional view of the FPC14 (FPC 14 with the LED12 attached) according to the embodiment. As shown in fig. 7, the LED12 fixes the third surfaces 12d3, 12e3 constituting the protruding portions 70a, 70b to the connecting

portions

21a, 21b by the

solders

60a, 60b. Although not shown in fig. 7, as described above, the second surfaces 12d2 and 12e2 and a part of the surfaces 12cd and 12ce constituting the projections 70a and 70b are fixed by the

solders

60a and 60b in addition to the third surfaces 12d3 and 12e 3.

Specifically, the LED12 is fixed to the connection portion 21a by the solder 60a, and the second surface 12d2 and the third surface 12d3 constituting the protruding portion 70a and a part of the surface 12cd are fixed to the connection portion 21b by the solder 60b, and the second surface 12e2 and the third surface 12e3 constituting the protruding portion 70b and a part of the surface 12ce are fixed to the connection portion 21b by the solder 60b. In other words, the LED12 fixes the side surfaces (the side surfaces 12d, 12e and the back surface 12c) intersecting the bottom surface 12b to the mounting surface 14a of the FPC 14. Accordingly, since it is not necessary to provide solder between the bottom surface 12b and the mounting surface 14a, it is possible to prevent the solder from floating upward (in the positive Z-axis direction), and thus it is possible to further reduce the weight of the planar lighting device 1.

In fig. 7, the case where the LED12 is viewed as a rectangular shape in cross section has been described, but the LED12 is not limited to a rectangular shape. A case where the LED12 has another shape will be described with reference to fig. 8 and 9.

Fig. 8 and 9 are cross-sectional views of an FPC14 according to a modification. As shown in fig. 8, the LED12 may include: the side surfaces 12d and 12e (the third surfaces 12d3 and 12e3) are partially cut to form cut portions 12da and 12ea, and are fixed by

solder

60a and 60b so as to fill the cut portions 12da and 12 ea.

In such a case, the notched portions 12da and 12ea are preferably provided at positions corresponding to the

connection portions

21a and 21 b. Specifically, the cut-out portions 12da and 12ea are preferably cut away to the end portions of the

connection portions

21a and 21b near the light-emitting surfaces 12a 1. By providing and fixing the

solders

60a and 60b up to the notches 12da and 12ea in this way, the mounting strength of the LED12 can be increased, and a narrower bezel can be realized.

As shown in fig. 9, the

solders

60a and 60b may be provided only inside the notches 12da and 12 ea. For example, the

solder

60a and 60b can be filled in the notches 12da and 12ea, and then the portions that have protruded from the side surfaces 12d and 12e can be removed.

In this way, the area of the

connection portions

21a and 21b in a plan view can be reduced (particularly, the length in the X-axis direction can be reduced), and the number of LEDs 12 per unit length in the longitudinal direction of the FPC14 can be increased.

As described above, the planar lighting device 1 according to the embodiment includes: a light guide plate 13, an LED12 (an example of a light source), an FPC14 (an example of a substrate), and a wiring 40. The light guide plate 13 emits light incident from the light incident surface 13 c. The LEDs 12 are arranged on the light incident surface 13c side and emit light from the light emitting surface 12a 1. The FPC14 has a mounting surface 14a on which the LED12 is mounted, facing the bottom surface 12b intersecting the light-emitting surface 12a1 of the LED 12. Wirings (wirings 40-1 to 22, wiring lines 40-1a, 40-11a, 40-12a, and 40-22a) are formed on the opposite surface 14b of the FPC14 on the side opposite to the mounting surface 14a, and connect the plurality of LEDs 12 in series.

Thus, since it is not necessary to provide a space for routing the wiring on the mounting surface 14a, the region at the outer edge of the upper and lower sides (Y-axis direction) of the connection disk parts 20-1 to 20 can be narrowed. In other words, in the planar lighting device 1 according to the embodiment, the length of the FPC14 in the Y axis direction, which is the short side direction, can be shortened, and thus a further narrow frame can be realized.

The present invention is not limited to the above embodiments. The present invention also encompasses an embodiment in which the above-described constituent elements are combined as appropriate. Further effects and modifications can be easily derived by those skilled in the art. Therefore, the present invention in its broader aspects is not limited to the above-described embodiments, and various modifications are possible.

Claims

1. A planar lighting device is provided with: a light guide plate, a plurality of light sources, a substrate, wiring, a land portion, and a conducting portion,

it is characterized in that the preparation method is characterized in that,

the light guide plate emits light incident from the light incident surface,

the plurality of light sources are arranged on the light incident surface side and emit the light from the light emitting surface,

the substrate is rectangular with the direction in which the intersecting portion of the light incident surface and the light emitting surface of the light guide plate extends being the long side direction, the substrate has a mounting surface which is opposed to the bottom surface of the light source intersecting the light emitting surface and on which the light source is mounted,

the wiring is formed on the opposite surface of the substrate opposite to the mounting surface and connects the plurality of light sources in series,

the connection pad section is provided on the mounting surface and connected to a pair of terminals of the light source,

the energizing portion is provided on the land portion and electrically connects the land portion and the opposite surface,

the light source has:

a protruding portion that is provided with the pair of terminals, respectively, and protrudes in a longitudinal direction of the substrate from a back surface side that is opposite to the light-emitting surface, of side surfaces that intersect with the light-emitting surface and the bottom surface, respectively,

the connection pad section includes a pair of connection sections connected to the pair of terminals,

the pair of connecting parts have notch parts with notches formed at mutually opposite positions,

the light source covers the notch portion in a predetermined area in a plan view,

the connecting part has:

a front arm portion formed on the light guide plate side with respect to the notch portion; and

a rear arm portion formed on the opposite side of the front arm portion with respect to the notch portion and having a smaller area than the front arm portion,

the current-carrying portion is provided to the forearm portion.

2. The planar lighting device according to claim 1,

the side surface of the protruding portion intersecting the bottom surface is connected to the connecting disc portion.

3. The planar lighting device according to claim 1 or 2,

the connecting portion has a region not covered by the predetermined region in a plan view.

4. A planar lighting device is provided with: a light guide plate, a plurality of light sources, a substrate, wiring, a land portion, and a conducting portion,

it is characterized in that the preparation method is characterized in that,

the light guide plate emits light incident from the light incident surface,

the substrate is rectangular with the direction of the extension of the intersection part of the light incident surface and the light emitting surface of the light guide plate as the long side direction, the substrate is provided with a mounting surface which is opposite to the bottom surface of the light source intersected with the light emitting surface and used for mounting the light source,

the wiring is provided only on the opposite surface and connected to the current-carrying portion,

the light source has:

the connecting part has:

the current-carrying portion is provided to the forearm portion.