JP2005294172A - Surface illumination device and display device using the same - Google Patents

Abstract

【Task】
Provided is a planar lighting device 120 that is excellent in impact resistance, has high light utilization efficiency, is small, light, thin, and inexpensive.
[Solution]
The planar lighting device 120 according to the present invention includes an LED FPC board 122, a white LED 121 that is electrically connected and fixed directly on the LED FPC board 122, and emits light on the side opposite to the LED FPC board 122 side. And the light guide plate 123 provided so that the light from the white LED 121 is incident from the side end face, and the LED FPC board 122 is fixed so as to contact the side end face of the light guide plate 123.
[Selection] Figure 1

Description

  The present invention relates to a planar illumination device and a display device using the same.

  In recent years, liquid crystal application products such as mobile phones have been strongly demanded to be smaller and lighter, and in response to this demand, liquid crystal display devices and planar lighting devices themselves used for them have been required to be smaller and lighter and thinner. Yes.

  A conventional planar illumination device has a light source such as a white light emitting diode (hereinafter abbreviated as “LED”) or a cold cathode fluorescent tube (CCFT) and a certain distance from the light source. A light guide plate that is provided open (via air), and light emitted from the light source is incident on a predetermined light incident surface of the light guide plate and then diffused throughout the light guide plate. Radiated in a planar shape from the surface (illumination surface).

  FIG. 5 is a schematic cross-sectional view showing a configuration of a liquid crystal display device 200 having such a conventional planar illumination device 220.

  The liquid crystal display device 200 includes a resin frame 210 that constitutes a housing of the liquid crystal display device 200, and a liquid crystal display panel 240 (hereinafter referred to as “liquid crystal display panel”) whose inner peripheral edge is fixed by the resin frame 210 with a light shielding sheet 230 The LCD panel 240 is fixed to the resin frame 210 so as to be connected to the LCD panel 240 and controls the operation of the LCD panel 240, and the LCD panel 240 and the resin. A planar illumination device 220 interposed between the frame 210 and a bezel 260 that is provided at a peripheral portion of the resin frame 210 and forms an outer frame of the liquid crystal display device 200.

  The planar lighting device 220 includes an LED flexible printed circuit board 222 (hereinafter, “flexible printed circuit” may be abbreviated as “FPC”) fixed to the resin frame 210, and an LED FPC board 222. A white LED 221 that is directly electrically connected and fixed thereon, a light guide plate 223 provided so that light from the white LED 221 is incident from a side end surface, a reflection sheet 224 provided on the back surface of the light guide plate 223, Condensing films 225 provided between the light guide plate 223 and the LCD panel 240.

  In the liquid crystal display device 200, the light emitted from the white LED 221 enters the light guide plate 223, is diffused inside the light guide plate 223, and is emitted as planar light toward the LCD panel 240. The planar light emitted from the light guide plate 223 is further diffused and collected by the light collecting films 225 and is incident on the entire LCD panel 240. Therefore, in the liquid crystal display device 200, the light emitted from the white LED 221 enters the entire LCD panel 240, and an image pattern can be displayed from the display area of the LCD panel 240.

  In the liquid crystal display device 200, when the liquid crystal display device 200 is subjected to an impact, the white LED 221 and the light guide plate 223 collide with each other to prevent the white LED 221 and the LED FPC board 222 from being disconnected. And the light guide plate 223 are spaced apart. However, when the white LED 221 and the LED FPC board 222 are spaced apart from each other, it is difficult to align the white LED 221 and the light guide plate 223, and the white LED 221 and the light guide plate 223 are planarly illuminated with high accuracy. There is a problem that it is difficult to incorporate the device 220 in a desired position.

  Further, in such a liquid crystal display device 200, since the white LED 221 and the light guide plate 223 are not integrated, a relative positional deviation between the white LED 221 and the light guide plate 223 may occur due to external impact or vibration. High nature. When the relative displacement between the white LED 221 and the light guide plate 223 occurs, there is a problem that the amount of light incident on the light guide plate 223 from the white LED 221 decreases, and the luminance of the liquid crystal display device 200 decreases.

  Further, in the liquid crystal display device 200, since the white LED 221 and the light guide plate 223 are spaced apart, an air layer is interposed between the light emitting surface of the white LED 221 and the light incident surface of the light guide plate 223. Accordingly, the light emitted from the white LED 221 passes through the air layer interposed between the white LED 221 and the light guide plate 223 and enters the light guide plate 223. However, since the refractive index of the air layer and the light guide plate 223 are greatly different from each other, the light reflectance at the interface between the air layer and the light guide plate 223 is high. Accordingly, the liquid crystal display device 200 has a problem that the light use efficiency is poor and the luminance is low.

  In view of such a problem, Patent Document 1 proposes a liquid crystal display device in which a light source and a light guide plate are fixed and integrated through a material having a refractive index larger than that of air and having elasticity.

  FIG. 6 is a schematic cross-sectional view illustrating a configuration of a liquid crystal display device 300 including the planar illumination device 320 described in Patent Document 1.

  The liquid crystal display device 300 includes a white LED 321 as a light source, a light guide plate 323 as a light guide that emits light from these light sources in a planar shape from a predetermined surface (illumination surface), and a resin frame constituting a housing. 310, an LED FPC board 322 on which white LEDs 321 are mounted by solder, a reflection sheet 324, a condensing film 325 made of a lens sheet or a light diffusion sheet, a TFT board, a CF board, etc., and a light shielding sheet 330 And an LCD panel 340 bonded to the resin frame 310 and a panel signal extracting FPC board 350 for extracting a signal from the LCD panel 340 to the outside.

  A resin layer 326 made of an elastic resin is formed in the gap between the light guide plate 323 and the white LED 321. As a result, light from the white LED 321 is efficiently incident on the light guide plate 323, and the white LED 321 is dropped or the wiring is cut when the white LED 321 collides with the light guide plate 323 or the resin frame 310 (due to a drop impact or the like). It is described that the occurrence of such troubles can be prevented in advance.

In the liquid crystal display device 300, a resin layer 326 having a refractive index larger than that of air is provided between the white LED 321 and the light guide plate 323. Therefore, since the difference in refractive index between the resin layer 326 and the light guide plate 323 is smaller than the difference in refractive index between the air layer and the light guide plate 323, the light reflectance by the light incident surface of the light guide plate 323 is relatively low. Get smaller. Therefore, the amount of light reflected by the light incident surface of the light guide plate 323 is reduced, and the amount of light incident on the light guide plate 323 is increased. Therefore, it is described that the liquid crystal display device 300 with high luminance can be realized.
Japanese Patent Application No. 2003-028498

  However, since the conventional liquid crystal display device 300 uses a side-view type white LED 321 that emits light from a side surface orthogonal to a surface connected to the LED FPC substrate 322 as a light source, the light source FPC substrate. It is necessary to stack 322 and the white LED 321 in the height direction of the liquid crystal display device 300. Therefore, in the liquid crystal display device 300, it is necessary to secure a space for the layer thickness of the white LED 321 and the layer thickness of the LED FPC board 322 between the reflection sheet 324 and the light collecting films 325. Therefore, the liquid crystal display device 300 has a problem that it is disadvantageous for making the planar illumination device 320 thin.

  Further, in the liquid crystal display device 300, since it is necessary to provide the resin layer 326 between the white LED 321 and the light guide plate 323 and between the white LED 321 and the resin frame 310, the number of members of the liquid crystal display device 300 increases. In addition, since the manufacturing process is complicated, there is a problem that high cost is required for manufacturing.

  The present invention has been made in view of the above points, and the object of the present invention is to provide a planar lighting device that is excellent in impact resistance, has high light utilization efficiency, is small, light, thin, and inexpensive. It is to provide a display device using the same.

A planar illumination device according to the present invention includes a flexible printed circuit board for a light source,
A light source that is electrically connected and fixed directly on the light source flexible printed circuit board and emits light on the opposite side of the light source flexible printed circuit board side;
A light guide plate provided so that light from the light source is incident from a side end surface;
Have
The light source flexible printed circuit board is fixed so as to be in contact with the side end face of the light guide plate.

  In the planar lighting device according to the present invention, the light source FPC board is fixed to the side end face of the light guide plate. That is, the light source and the FPC board for the light source are disposed by being stacked in parallel in the planar direction of the planar lighting device, and are fixed to each other. Therefore, the planar illumination device according to the present invention is more advantageous in reducing the thickness than the conventional configuration in which the light source FPC board and the light guide plate are stacked in the height direction of the planar illumination device.

  In the planar lighting device according to the present invention, the light source FPC board and the light guide plate, to which the light source is electrically connected and fixed, are fixed to each other. That is, the light source, the FPC board for light source, and the light guide plate are fixed and integrated. Therefore, even when an impact is applied to the planar lighting device, there is little possibility of disconnection or the like between the light source and the light source FPC board, and no relative displacement between the light source and the light guide plate occurs. . Therefore, a planar lighting device with high impact durability can be realized.

  In the planar illumination device according to the present invention, the light source may be a light emitting diode.

  Light emitting diodes are less expensive, consume less power, are smaller, lighter, and thinner than cold cathode fluorescent tubes that have been widely used as conventional light sources. Therefore, according to this configuration, it is possible to realize a planar lighting device that is small, lightweight, thin, consumes less power, and is inexpensive.

  In the planar lighting device according to the present invention, the light guide plate may be provided with a light source storage portion for storing the light source.

  According to this configuration, the light source is housed in the light source housing section provided on the light guide plate. Therefore, the light source does not protrude from the side end surface of the light guide plate, and a small and lightweight planar illumination device can be realized.

  In the planar illumination device according to the present invention, the light source may be provided so as to contact a side end surface of the light guide plate.

  According to this configuration, the light source is provided so as to contact the side end surface of the light guide plate. That is, the light emitting surface of the light source and the side end surface of the light guide plate are completely in contact with each other without air. Therefore, the reflection of light between the light emitting surface of the light source and the side end surface of the light guide plate is suppressed as compared with the configuration in which the conventional light source and the light guide plate are arranged separately. Therefore, according to this configuration, it is possible to realize a planar illumination device having a higher light utilization efficiency than a configuration in which the light source and the light guide plate are spaced apart. Further, according to this configuration, since the light source and the light guide plate are provided in contact with each other, the positioning of the light source and the light guide plate is relatively easy, and the desired position in the planar illumination device can be accurately set. A light source and a light guide plate can be arranged.

  Moreover, the planar illuminating device which concerns on this invention WHEREIN: The contact surface with the said light-guide plate of the said flexible printed circuit board for light sources may be comprised by the light reflection surface.

  According to this configuration, the light incident on the light guide plate from the light source and emitted in the direction of the light source FPC substrate by repeating the light guide in the light guide plate is the light guide plate of the light source FPC substrate configured on the light reflecting surface. Is reflected in the direction of the light guide plate by the contact surface. The light reflected by the light source FPC board is incident again on the light guide plate, diffused by the light guide plate, and emitted from the planar illumination device. Therefore, the utilization efficiency of the light emitted from the light source can be improved, and a planar illumination device having a higher utilization efficiency of light can be realized.

In the planar illumination device according to the present invention, the light source flexible printed circuit board and the side end surface of the light guide plate are fixed by a thin double-sided tape,
The double-sided tape may be formed of a material having colorless transparency.

  According to this configuration, the light source FPC board and the side end face of the light guide plate are bonded together by an inexpensive double-sided tape. Therefore, an inexpensive planar illumination device can be realized.

  Further, according to this configuration, the light source FPC board and the side end face of the light guide plate are bonded together by an extremely thin double-sided tape. Therefore, a small and light planar illumination device can be realized. Here, the thin double-sided tape refers to a double-sided tape having a thickness of 100 μm or less. A more preferable thickness of the double-sided tape is 50 μm or less.

  Moreover, according to this structure, the double-sided tape which adhere | attaches the light source FPC board and light guide plate which are comprised on the light reflection surface is comprised with the material which has transparency. Therefore, it is possible to suppress light absorption by the double-sided tape of light that enters the contact surface with the side end surface of the light guide plate of the light source FPC board formed on the light reflection surface and is reflected by the contact surface. Therefore, the light emitted in the direction of the light source FPC board is reflected with a high reflectance and re-enters the light guide plate, so that the light use efficiency is high. Therefore, it is possible to realize a planar illumination device having high light utilization efficiency.

  In the planar lighting device according to the present invention, the flexible printed circuit board for light source may have a width equal to or less than a maximum thickness of the light guide plate.

  When the width of the light source FPC board is larger than the maximum thickness of the light guide plate, the light source FPC board protrudes from the light guide plate. According to this configuration, the light source FPC board does not protrude from the light guide plate. Therefore, a thinner planar illumination device can be realized.

  The display device according to the present invention includes the planar illumination device according to the present invention.

  As described above, the planar lighting device according to the present invention is excellent in impact resistance, has high light utilization efficiency, is small, light, thin, and can be manufactured at low cost. Therefore, according to the present invention, it is possible to realize a display device that is excellent in impact resistance, has high light utilization efficiency, and is small, light, thin, and inexpensive.

  The display device according to the present invention does not limit the display format at all. For example, the display format may be a liquid crystal display format or the like.

  As described above, according to the present invention, the light source and the FPC board for the light source can be bonded and fixed in the plane direction of the liquid crystal display device, so that high impact resistance, high light utilization efficiency, thinning, and Low cost can be realized.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic plan view of a planar illumination device 120 according to the present invention.

  FIG. 2 is a schematic cross-sectional view of a portion indicated by II in FIG.

  FIG. 3 is a schematic enlarged perspective view of a portion indicated by III in FIG.

  The planar illumination device 120 is an LED FPC board 122 and a top-view type that emits light to the opposite side of the LED FPC board 122 side by being electrically bonded and fixed directly to the LED FPC board 122 with solder 126. White LED 121, light guide plate 123 provided so that light from white LED 121 is incident from the side end surface, reflection sheet 124 provided on the back surface of light guide plate 123, and a collection disposed on light guide plate 123. It consists of optical films 125 (not shown) and a resin frame 110 that forms the casing of the planar lighting device 120.

  The condensing films 125 are not drawn in FIGS. Moreover, although three white LED121 is drawn in FIGS. 1-3, this is a mere illustration and the quantity of white LED121 which the planar illumination apparatus 120 has is not limited at all.

  The resin frame 110 constitutes a housing of the planar illumination device 120 and has a function of ensuring the mechanical strength of the planar illumination device 120. The material of the resin frame 110 is not limited at all, but, for example, a polycarbonate resin such as LD-1000RM or LN-1000RM, which is Panlite (trademark) manufactured by Teijin Chemicals Co., Ltd., which is a light reflection type, can be used.

  The condensing films 125 are made of a lens sheet, a light diffusion sheet, or the like, and have a function of uniformly diffusing and condensing light emitted from the light guide plate 123 over the entire effective light emitting region of the planar illumination device 120.

  The white LED 121 has a function as a light source, and is electrically connected and fixed directly to the LED FPC board 122 by solder 126. The white LED 121 is smaller, lighter, thinner, consumes less power, and is less expensive than a cold cathode fluorescent tube or the like that has been widely used as a light source for conventional planar lighting devices. Therefore, by using the white LED 121 as the light source, it is possible to realize a planar lighting device 120 that is small, light, thin, consumes less power, and is inexpensive. However, the light source is not limited to a white LED, and the light source can be constituted by a known light source such as an organic electroluminescence element or a plasma light source.

  The white LED 121 is a so-called top view type LED that emits light on the side opposite to the LED FPC board 122 side. Therefore, the LED FPC board 122 can be fixed to the side end surface of the light guide plate 123, and the LED FPC board 122 and the light guide plate 123 can be arranged to be stacked in the planar direction of the planar illumination device 120. Accordingly, the light source and the LED FPC board 122 are stacked in the height direction of the planar illumination device 120 as in the case of using a side view type LED that emits light in a direction perpendicular to the LED FPC board 122 side. Thus, a thinner planar illumination device 120 can be realized.

  The LED FPC board 122 includes a control circuit for the white LED 121 and is a flexible board. The LED FPC board 122 may be formed by coating a conductive metal layer wiring such as copper foil with a resin having heat resistance, chemical resistance, electrical insulation, mechanical strength, and flexibility such as polyimide. it can.

  In the planar lighting device 120, the contact surface 128 of the LED FPC board 122 with the light guide plate 123 is formed as a light reflecting surface. Therefore, the light incident on the light guide plate 123 and emitted in the direction of the LED FPC board 122 by repeating the light guide in the light guide plate 123 is reflected in the direction of the light guide plate 123 by the contact surface 128 formed on the light reflection surface. Is done. The light reflected by the LED FPC board 122 is incident again on the light guide plate 123, diffused and reflected by the light guide plate 123, and emitted from the planar illumination device 120. Therefore, the utilization efficiency of the light emitted from the white LED 121 can be improved. Therefore, the planar illumination device 120 having high light utilization efficiency can be realized.

  The contact surface 128 configured as the light reflecting surface is, for example, an ESR (Enhanced Specular Reflector) sheet having a multilayer film structure of Ag, Al, white resin, or polyester resin on the LED FPC board 122. It can be formed by forming a film by a known film forming method. Since the white LED 121 is electrically connected to the LED FPC board 122 by solder 126, the contact surface 128 is preferably formed of a thin film made of white resin or the like which is an electrically insulating material. . Further, from the viewpoint of the light use efficiency of the planar illumination device 120, the contact surface 128 configured as a light reflection surface preferably has a light reflectance of 90% to 100%, and the light reflectance. Is more preferable as it is close to 100%.

  In the planar lighting device 120, the LED FPC board 122 is configured to have a width equal to or less than the maximum thickness of the light guide plate 123. Therefore, the FPC board 122 for LED does not protrude from the light guide plate 123, and a thinner planar illumination device 120 can be realized.

  In the planar lighting device 120, the light guide plate 123 and the LED FPC board 122 are bonded and fixed by a double-sided tape 127. Further, as described above, the white LED 121 and the LED FPC board 122 are bonded and fixed to each other by the solder 126. Therefore, the white LED 121, the LED FPC board 122, and the light guide plate 123 are fixedly integrated with each other. Therefore, even when an impact is applied to the planar lighting device 120, the white LED 121 collides with the light guide plate 123 and the like, the white LED 121 and the LED FPC board 122 are disconnected, and the white LED 121 and the light guide plate. It is possible to effectively prevent the relative position with respect to 123 from shifting. Therefore, the planar lighting device 120 having high impact durability can be realized.

  Further, since the light guide plate 123 and the LED FPC board 122 are fixed and integrated with an inexpensive double-sided tape 127, the light guide plate 123 and the LED FPC board 122 can be easily and inexpensively bonded and fixed. it can. Therefore, an inexpensive planar illumination device 120 can be realized.

  Further, the double-sided tape 127 has a thin thickness of 100 μm or less. Therefore, the small and light planar illumination device 120 can be realized.

  The double-sided tape 127 is made of a material having colorless transparency. Therefore, the light emitted from the light guide plate 123 toward the LED FPC board 122 is not absorbed by the double-sided tape 127, but is directed toward the light guide plate 123 by the contact surface 128 of the LED FPC board 122 formed on the light reflecting surface. Reflected with high efficiency. Therefore, the planar illumination device 120 having high light utilization efficiency can be realized. The colorless and transparent material that can be used for the double-sided tape 127 is not limited in any way, and examples thereof include a transparent polyester film substrate coated with an acrylic pressure-sensitive adhesive. . Further, the double-sided tape 127 is more preferably 95% to 100% in light transmittance from the viewpoint of the light reflectance of the contact surface 128, and more preferably closer to 100%.

  The light guide plate 123 has a function of receiving light emitted from the white LED 121, guiding the received light to the entire light guide plate, and forming a surface light source. The material of the light guide plate 123 is not limited in any way. For example, an acrylic resin such as Acrylite E (trademark) manufactured by Mitsubishi Engineering Plastics, or Taflon (trademark) # 1700 manufactured by Idemitsu Petrochemical Co., Ltd. A polycarbonate resin or the like can be used.

  The light guide plate 123 is provided with an LED storage portion 129 for storing the white LED 121 on the side end surface. Therefore, the white LED 121 does not protrude from the side end surface of the light guide plate 123, and a small and lightweight planar illumination device 120 can be realized.

  In the planar lighting device 120, the light emitting surface 121 a of the white LED 121 is provided so as to contact the side end surface of the light guide plate 123. Therefore, when manufacturing the planar lighting device 120, the relative position between the white LED 121 and the light guide plate 123 can be easily positioned. Therefore, the surface illumination device 120 is easy to manufacture.

  In the planar illumination device 120, the light emitting surface 121a of the white LED 121 is in contact with the side end surface of the light guide plate 123, and no air is interposed between the light emitting surface 121a and the side end surface of the light guide plate 123. Therefore, compared with the case where an air layer is interposed between the light emitting surface 121a and the side end surface of the light guide plate 123, light emission from the white LED 121 between the light emitting surface 121a and the side end surface of the light guide plate 123 is performed. Is suppressed. Therefore, the planar lighting device 120 having higher light utilization efficiency can be realized.

  In the planar lighting device 120, the LED storage portion 129 has a shape that is substantially the same as that of the white LED 121. Therefore, the white LED 121 is accommodated in the LED accommodating portion 129. Therefore, the white LED 121 and the light guide plate 123 are more firmly fixed, and even when an impact, vibration, or the like is applied to the planar illumination device 120, the relative positional deviation between the white LED 121 and the light guide plate 123, and The disconnection between the white LED and the LED FPC board 122 can be effectively prevented.

  On the bottom surface of the light guide plate 123, a reflection sheet 124 for reflecting the direction of light incident on the light guide plate 123 from the white LED 121 in the direction of the LCD panel 140 is provided. The reflection sheet 124 is not limited at all, and, for example, white PET (white polyethylene terephthalate) or the like is used.

  FIG. 4 is a schematic cross-sectional view of the liquid crystal display device 100 according to the present invention.

  The liquid crystal display device 100 is connected to the resin frame 110 constituting the housing of the liquid crystal display device 100, the LCD panel 140 having a peripheral portion fixed to the resin frame 110 by the light shielding sheet 130, and the LCD panel 140. Further, the FPC board 150 for taking out panel signals fixed by the resin frame 110, the bezel 160 provided on the peripheral portion of the resin frame 110 and forming the outer frame of the liquid crystal display device 100, and the LCD panel 140 are provided. And a planar illumination device 120 that supplies light to the LCD panel 140.

  The bezel 160 forms an outer frame of the liquid crystal display device 100. The material of the bezel 160 is not limited in any way, but for example, a metal such as tinplate or stainless steel can be used.

  The panel signal extraction FPC board 150 includes a control circuit for the LCD panel 140 and is a flexible board. The panel signal extracting FPC board 150 is formed by coating a conductive metal layer wiring such as copper foil with a resin having heat resistance, chemical resistance, electrical insulation, mechanical strength, and flexibility such as polyimide. be able to.

  The LCD panel 140 is bonded and fixed to the resin frame 110 with a light shielding sheet 130. The configuration of the LCD panel 140 is not limited at all, and a known LCD panel can be used.

  As described above, the planar lighting device 120 is excellent in impact resistance, has high light utilization efficiency, is small, light, thin, and can be manufactured at low cost.

  Therefore, by using such a planar illumination device 120, it is possible to realize a liquid crystal display device 100 that is excellent in impact resistance, has high light utilization efficiency, and is small, light, thin, and inexpensive.

  In this embodiment, as an example of the display device according to the present invention, the liquid crystal display device 100 in which the display format is a liquid crystal display format has been described. However, the present invention is not limited to this.

It is a schematic plan view of the planar illumination device 120 according to the present invention. It is a schematic sectional drawing of the part shown by II of FIG. FIG. 3 is a schematic enlarged perspective view of a portion indicated by III in FIG. 1. 1 is a schematic cross-sectional view of a liquid crystal display device 100 according to the present invention. It is a schematic sectional drawing which shows the structure of the liquid crystal display device 200 which has the conventional planar illumination apparatus 220. It is a schematic sectional drawing which shows the structure of the liquid crystal display device 300 which has the planar illuminating device 320 described in patent document 1. FIG.

Explanation of symbols

100, 200, 300 Liquid crystal display device 110, 210, 310 Resin frame 120, 220, 320 Planar illumination device 121, 221, 321 White LED
121a Light exit surface 122, 222, 322 LED FPC board 123, 223, 323 Light guide plate 124, 224, 324 Reflective sheet 125, 225, 325 Condensing films 126 Solder 127 Double-sided tape 128 Contact surface 129 LED storage unit 130, 230, 330 Light-shielding sheet 140, 240, 340 LCD panel (liquid crystal display panel)
150, 250, 350 FPC board for panel signal extraction 160, 260, 360 Bezel 326 Resin layer

Claims (8)

A flexible printed circuit board for a light source;
A light source that is electrically connected and fixed directly on the flexible printed circuit board for the light source and emits light on the opposite side of the flexible printed circuit board side for the light source;
A light guide plate provided so that light from the light source is incident from a side end surface;
A planar lighting device comprising:
The planar lighting device, wherein the light source flexible printed circuit board is fixed so as to contact a side end surface of the light guide plate. The planar lighting device according to claim 1,
A planar illumination device in which the light source is a light emitting diode. The planar lighting device according to claim 1,
A planar illumination device in which the light guide plate is formed with a light source storage portion for storing the light source. The planar lighting device according to claim 1,
The planar illumination device is provided so that the light source is in contact with a side end surface of the light guide plate. The planar lighting device according to claim 1,
A planar illumination device in which a contact surface of the flexible printed circuit board for the light source with the light guide plate is configured as a light reflecting surface. The planar lighting device according to claim 1,
The flexible printed circuit board for the light source and the side end surface of the light guide plate are fixed by a thin double-sided tape,
The double-sided tape is a planar lighting device formed of a material having colorless transparency. The planar lighting device according to claim 1,
The light source flexible printed circuit board is a planar illumination device having a width equal to or less than a maximum thickness of the light guide plate. A display device comprising the planar illumination device according to claim 1.

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