JP2010009845A - Illumination unit, and liquid crystal display therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illumination unit which has a heat radiation structure capable of extending the life of light emitting diodes and which enables a light source unit with light emitting diodes to be replaced easily. <P>SOLUTION: An accommodation section 30 formed by one end surface 22c of a light guide 22 and a frame 23 is configured to allow insertion and removal of the light source unit 21. The light source unit includes light emitting diodes 41 each having a light emission surface substantially parallel to a mounting surface, a film substrate 42 on which the plurality of light emitting diodes are arranged in a first direction and mounted, a heat radiation member 43 having a support portion 43A for supporting the film substrate and a reflection portion 43B extending from the support portion in a second direction perpendicular to the first direction, and an adhesive tape 44 for adhering the film substrate to the support portion and having heat radiation properties. In a state in which the light emitting diode is accommodated in the accommodation section, the light emitting surface of the light emitting diode is opposed to one end surface of the light guide and the reflection portion of the heat radiation member covers the accommodation section. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an illumination unit and a liquid crystal display device including the illumination unit, and more particularly to an illumination unit including a light emitting diode (LED) as a light source and a liquid crystal display device including the illumination unit.

  Liquid crystal display devices are utilized in various fields as display devices for OA equipment such as personal computers and televisions, taking advantage of features such as light weight, thinness, and low power consumption. In recent years, liquid crystal display devices are also used as mobile terminal devices such as mobile phones, display devices such as car navigation devices and game machines.

  As such a liquid crystal display device, a reflection type that selectively reflects external light to display an image, a transmission type that selectively transmits backlight light to display an image, and a reflection type and transmission type A module such as a transflective module that has both functions of a mold has been developed.

  Among these, the transmissive liquid crystal display device includes a transmissive liquid crystal display panel and an illumination unit (that is, a backlight) disposed on the back side of the liquid crystal display panel. In recent years, as a lighting unit mounted on such a liquid crystal display device, a light emitting diode applied as a light source has been put into practical use.

  For example, according to Patent Document 1, a plurality of semiconductor light emitting devices (LEDs or light emitting diodes) having a light emitting surface that is substantially perpendicular to the mounting surface are mounted in a row on one surface of a film substrate, and light emission of the semiconductor light emitting device is performed. A backlight device is disclosed that is housed in a metal frame with one surface of a film substrate attached to the surface of the light guide plate so that the surface is in close contact with the light incident surface of the light guide plate.

In particular, according to this Patent Document 1, in order to release heat generated in the semiconductor light emitting element to the metal frame, a heat radiating metal thin film is provided on almost the entire other surface of the film substrate where the semiconductor light emitting element is not mounted. The metal thin film is pressed by the metal frame. Further, according to Patent Document 1, a so-called side view type LED is used as a semiconductor light emitting element, and the film substrate is firmly bonded over a wide area of the light guide plate.
JP 2003-76287 A

  The light emitting diode has a characteristic of generating heat during operation and has a characteristic of being easily deteriorated in a high temperature environment. For this reason, in order to extend the life of the light emitting diode, it is desired to improve the heat dissipation efficiency and drive in a low temperature environment.

  In addition, when a light emitting diode deteriorates, it is desired that it can be easily replaced. As in Patent Document 1, in the configuration in which the film substrate on which the LED is mounted is bonded to the light guide plate, it is necessary to disassemble the backlight device and peel the film substrate from the light guide plate. More complicated.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to have a heat dissipation structure capable of extending the life of a light emitting diode and to easily replace a light source unit including the light emitting diode. An object of the present invention is to provide an illumination unit and a liquid crystal display device including the illumination unit.

A lighting unit according to an aspect of the present invention comprises:
A light guide plate;
A frame for holding the light guide plate and forming an accommodating portion apart from one end surface of the light guide plate;
A light source unit housed in the housing portion,
The housing is configured to be detachable from the light source unit,
The light source unit includes: a light emitting diode having a light emitting surface that is substantially parallel to a mounting surface; a film substrate on which a plurality of the light emitting diodes are mounted side by side in a first direction; a support unit that supports the film substrate; A heat-dissipating member having a reflecting portion extending in a second direction orthogonal to the first direction from a support portion; and an adhesive tape that adheres the film substrate to the support portion and has a heat dissipation property; The light emitting surface of the light emitting diode faces the one end surface of the light guide plate and the reflecting portion of the heat radiating member covers the housing portion.

A liquid crystal display device according to an aspect of the present invention includes:
A liquid crystal display panel holding a liquid crystal layer between a pair of substrates;
An illumination unit that is disposed on the liquid crystal display panel and illuminates the liquid crystal display panel,
The lighting unit is:
A light guide plate;
A frame for holding the liquid crystal display panel and the light guide plate and forming an accommodating portion apart from one end surface of the light guide plate;
A light source unit housed in the housing portion,
The housing is configured to be detachable from the light source unit,
The light source unit includes: a light emitting diode having a light emitting surface that is substantially parallel to a mounting surface; a film substrate on which a plurality of the light emitting diodes are mounted side by side in a first direction; a support unit that supports the film substrate; A heat-dissipating member having a reflecting portion extending in a second direction orthogonal to the first direction from a support portion; and an adhesive tape that adheres the film substrate to the support portion and has a heat dissipation property; The light emitting surface of the light emitting diode faces the one end surface of the light guide plate and the reflecting portion of the heat radiating member covers the housing portion.

  According to the present invention, there is provided an illumination unit having a heat dissipation structure capable of extending the life of a light-emitting diode, and capable of easily replacing a light source unit including the light-emitting diode, and a liquid crystal display device including the illumination unit. be able to.

  That is, the light source unit includes a plurality of light emitting diodes mounted side by side in the first direction. The light source unit is accommodated in an accommodating portion formed by one end surface of the light guide plate and a frame. The housing part is configured so that the light source unit can be attached and detached, and in a state where the light source unit is housed in the housing part, the reflecting part of the heat dissipation member covers the housing part. For this reason, it becomes possible to replace | exchange a light source unit easily by pulling out a light source unit from an accommodating part.

  In the light source unit, the film substrate on which a plurality of light emitting diodes as heat sources are mounted is bonded to the support portion of the heat radiating member with a heat radiating adhesive tape. Thus, since the film substrate closer to the heat source is bonded to the heat dissipation member, the heat generated in the light emitting diode is directly transmitted from the film substrate to the heat dissipation member via the adhesive tape without passing through a heat insulating material such as air, Heat dissipation efficiency can be improved.

  Thereby, the light emitting diode can be driven in a low temperature environment, and the life of the light emitting diode can be extended.

  Hereinafter, an illumination unit and a liquid crystal display device according to an embodiment of the present invention will be described with reference to the drawings. Here, a liquid crystal display device having a transmissive display function for selectively transmitting backlight light from a backlight unit, which is an illumination unit, and displaying an image will be described.

  That is, as shown in FIG. 1, the liquid crystal display device 1 includes a transmissive liquid crystal display panel 2 having a substantially rectangular flat plate shape, and a backlight unit 15 that illuminates the liquid crystal display panel 2. The liquid crystal display panel 2 is configured by holding a liquid crystal layer between a pair of substrates. That is, the liquid crystal display panel 2 includes a substantially rectangular array substrate 3 and a counter substrate 4, and a liquid crystal layer 5 sealed between the array substrate 3 and the counter substrate 4. The array substrate 3 and the counter substrate 4 are bonded to each other through a sealing material (not shown).

  The liquid crystal display panel 2 includes a substantially rectangular active area 6 for displaying an image on the inner side surrounded by a sealing material. The active area 6 is composed of a plurality of pixels PX arranged in a matrix.

  In the active area 6, the array substrate 3 includes a plurality of scanning lines Y (1, 2,...), A plurality of signal lines X (1, 2,...), A switching element 7 disposed in each pixel PX, and each pixel PX. The pixel electrode 8 connected to the switching element 7 is provided. The pixel electrode 8 is formed of a light-transmitting conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

  Each scanning line Y extends along the row direction of the pixel PX. Each signal line X extends along the column direction of the pixels PX so as to intersect with each scanning line Y via an insulating layer. Each switching element 7 is disposed in a region including an intersection of the scanning line Y and the signal line X.

  The switching element 7 is composed of, for example, a thin film transistor (TFT) having a semiconductor layer formed of amorphous silicon, polysilicon, or the like. The gate electrode 7G of the switching element 7 is electrically connected to the corresponding scanning line Y (or formed integrally with the scanning line). The source electrode 7S of the switching element 7 is electrically connected to the corresponding signal line X (or formed integrally with the signal line). The drain electrode 7D of the switching element 7 is electrically connected to the pixel electrode 8 of the corresponding pixel PX.

  The common electrode 9 for applying a voltage to the liquid crystal layer 5 due to a potential difference with the pixel electrode 8 may be provided on the array substrate 3 or on the counter substrate 4. That is, in the horizontal electric field mode mainly using the horizontal electric field (electric field substantially parallel to the main surface of the substrate), the array substrate 3 has the common electrode 9 that is electrically insulated from the pixel electrode 8 and opposed to the pixel electrode 8. I have. In the vertical electric field mode mainly using the vertical electric field (electric field substantially perpendicular to the main surface of the substrate), the counter substrate 4 includes a common electrode 9 that faces the pixel electrode 8 with the liquid crystal layer 5 interposed therebetween. Similar to the pixel electrode 8, the common electrode 9 is formed of a light-transmitting conductive material.

  The surfaces of the array substrate 3 and the counter substrate 4 that are in contact with the liquid crystal layer 5 are each covered with an alignment film. The array substrate 3 and the counter substrate 4 are bonded to each other with the alignment films facing each other via a spacer (not shown) (for example, a columnar spacer formed integrally with one substrate). At this time, a predetermined gap is formed between the array substrate 3 and the counter substrate 4 by a spacer. The liquid crystal layer 5 is formed of a liquid crystal composition sealed in the gap between the array substrate 3 and the counter substrate 4.

  In the liquid crystal display panel 2, optical elements OD1 and OD2 are provided on the outer surface of the array substrate 3 and the outer surface of the counter substrate 4, respectively. These optical elements OD1 and OD2 include a polarizing plate whose polarization direction is set in accordance with the characteristics of the liquid crystal layer 5. Further, the optical elements OD1 and OD2 may include a retardation plate as necessary.

  In the color display type liquid crystal display device, the liquid crystal display panel 2 includes a plurality of types of pixels in the active area 6, for example, a red pixel that displays red (R), a green pixel that displays green (G), and a blue (B). Has a blue pixel. That is, the red pixel includes a red color filter that transmits light having a red main wavelength. The green pixel includes a green color filter that transmits light having a green dominant wavelength. The blue pixel includes a blue color filter that transmits light having a blue main wavelength. These color filters are arranged on the main surface of the array substrate 3 or the counter substrate 4.

  The liquid crystal display device 1 includes a bezel cover 11 having a rectangular frame shape. The bezel cover 11 includes a rectangular window portion 11A that exposes the active area 6 of the liquid crystal display panel 2, and a rectangular frame-shaped main body portion 11B that defines the window portion 11A. The liquid crystal display panel 2 configured as described above is sandwiched between the backlight unit 15 and the bezel cover 11. At this time, the backlight unit 15 is arranged with the surface thereof facing the back side of the liquid crystal display panel 2 (that is, the array substrate side), and illuminates the liquid crystal display panel 2 from the back side.

  As shown in FIG. 2, the backlight unit 15 includes a light source unit 21, a light guide plate 22, a frame 23, a back cover 25, an optical sheet 26, and the like.

  The light guide plate 22 has a function of guiding emitted light from the light source unit 21 toward the liquid crystal display panel 2. The light guide plate 22 is made of a light-transmissive resin material such as acrylic resin or polycarbonate resin. The light guide plate 22 includes a wedge-type plate having a thin portion at one end and a thick portion at the other end opposed to the thin portion, and a flat plate type having a substantially uniform thickness over the whole. However, in this embodiment, a rectangular flat plate type is adopted.

  The light guide plate 22 includes a rectangular first main plane 22a facing the liquid crystal display panel 2, a rectangular second main plane 22b facing the first main plane 22a, and the first main plane 22a. And four rectangular end faces connecting the second main plane 22b. The one end surface 22 c functions as an incident surface facing the light source unit 21. Further, the first main plane 22 a functions as an emission surface that emits light toward the liquid crystal display panel 2.

  The frame 23 is mainly configured to hold the light guide plate 22. The frame 23 is also configured to hold the liquid crystal display panel 2. Such a frame 23 is made of a resin material. The frame 23 is separated from the one end face 22c of the light guide plate 22, and the accommodating portion 30 is formed between the one end face 22c. The bezel cover 11 is fixed to the frame 23 by a method such as caulking or screwing in a state where the liquid crystal display panel 2 is sandwiched between the bezel cover 11 and the frame 23.

  The accommodating portion 30 is a space having a substantially U-shaped cross section formed between the one end surface 22c of the light guide plate 22 and the frame 23, and extends in the normal direction of the paper surface in FIG. The accommodating portion 30 corresponds to a space that can accommodate the light source unit 21 described in detail later, and extends in a direction parallel to the extending direction of the light source unit 21.

  The back cover 25 is generally formed in a box shape and can store the light guide plate 22 and the like together with the frame 23 and the like. Further, the back cover 25 has a convex portion 25 </ b> X that protrudes toward the back side of the backlight unit 15. The convex portion 25X extends in the normal direction of the paper surface in FIG.

  As the optical sheet 26, an optical sheet 26 </ b> A disposed between the liquid crystal display panel 2 and the first main plane 22 a of the light guide plate 22, and a back cover 25 and the second main plane 22 b of the light guide plate 22. An arranged optical sheet 26B is provided. The optical sheet 26A is, for example, a light condensing sheet, a diffusion sheet, a sheet having a plurality of optical functions, and the like, and imparts predetermined optical characteristics to the light emitted from the light guide plate 22 to the liquid crystal display panel 2. Lead. The optical sheet 26 </ b> B is a reflection sheet, and reflects the light leaking from the second main plane 22 b of the light guide plate 22 toward the light guide plate 22 again. These optical sheets 26 are formed in a substantially rectangular shape having substantially the same size as the first main plane 22 a and the second main plane 22 b of the light guide plate 22.

  As shown in FIGS. 3 and 4, the light source unit 21 has a shape extending in the first direction D1, and is a light emitting diode (LED) 41, a film substrate 42, a heat radiating member 43, and an adhesive tape 44, which are point light sources. And so on.

  The light emitting diode 41 is a semiconductor light emitting element having a light emitting surface 41 </ b> E that is substantially parallel to a mounting surface mounted on the film substrate 42. The film substrate 42 is formed in a strip shape extending in the first direction D1 (that is, a substantially rectangular shape having a long side along the first direction D1). The plurality of light emitting diodes 41 are mounted on the film substrate 42 side by side in the first direction D1. In the example shown in FIG. 3 and the like, the plurality of light emitting diodes 41 are arranged in a line along the first direction D1, but may be arranged in a plurality of lines.

  The heat radiating member 43 includes a support portion 43A that supports the film substrate 42, and a reflection portion 43B that extends from the support portion 43A in a second direction D2 orthogonal to the first direction D1. The support portion 43A and the reflection portion 43B are integrally formed so as to have a substantially L-shaped cross section.

  That is, the support portion 43A has a substantially rectangular shape having long sides along the first direction D1 and short sides along the third direction D3 orthogonal to the first direction D1 and the second direction D2. . The length of the short side along the third direction D3 of the support portion 43A is equal to or greater than the width of the film substrate 42 (that is, the length of the short side of the rectangle). The reflection portion 43B has a substantially rectangular shape having long sides along the first direction D1 and short sides along the second direction D2. One long side of the support part 43A and one long side of the reflection part 43B are connected. In the example shown here, the other long side of the support portion 43A is similarly connected to the other reflection portion 43C, and the heat radiating member 43 is formed to have a substantially U-shaped cross section.

  Moreover, this heat radiating member 43 is provided with the insertion part 43E in the one end side along the 1st direction D1. In the example shown in FIG. 3, the insertion part 43E is formed on the extended surface of the reflection part 43B. Moreover, in the heat radiating member 43, the screw | thread SC is attached to the other end side along the 1st direction D1. In the example illustrated in FIG. 3, the screw SC is inserted into a screw hole formed in the extended surface of the reflecting portion 43 </ b> B from the back side of the backlight unit 15 toward the third direction D <b> 3.

  Further, the heat radiating member 43 has a convex portion 43X extending in the first direction D1 at the reflecting portion 43B. The convex portion 43X protrudes from the back side of the backlight unit 15 toward the inside surrounding the light emitting diode 41. Thereby, the rigidity of the heat radiating member 43 and the light source unit 21 can be improved.

  Such a heat radiating member 43 is formed of a metal material having heat radiating properties such as stainless steel (SUS) or aluminum (Al). The reflecting portions 43B and 43C are formed so that the surface surrounding the light emitting diode 41 has light reflectivity, and reflects a part of the light emitted from the light emitting diode 41.

  The adhesive tape 44 bonds the film substrate 42 on which the plurality of light emitting diodes 41 are mounted to the support portion 43A. At this time, the light emitting surface 41E of the light emitting diode 41 faces the second direction D2. The adhesive tape 44 is made of a material having heat dissipation properties.

  The accommodating part 30 mentioned above is comprised so that attachment or detachment of the light source unit 21 of such a structure is possible. That is, as shown in FIGS. 5 and 6, the accommodating portion 30 having a substantially U-shaped cross section formed between the one end face 22 c of the light guide plate 22 and the frame 23 is not surrounded by these. Part 30F. Further, the frame 23 constituting the housing part 30 has a recess 30 </ b> A into which the insertion part 43 </ b> E of the light source unit 21 is inserted. Further, the frame 23 is provided with a screw hole 30B in which a screw SC inserted into the reflecting portion 43B of the light source unit 21 is fastened.

  The operation of attaching the light source unit 21 to the housing unit 30 is performed according to the following procedure. That is, from the back side of the backlight unit 15, the insertion portion 43E of the light source unit 21 is inserted into the recess 30A of the frame 23, and then the support portion 43A including the light emitting diode 41 is inserted from the opening portion 30F. At this time, the reflecting portion 43B is disposed along the convex portion 25X of the back cover 25, and a part thereof overlaps the back cover 25 (that is, the back side of the backlight unit 15). The open portion 30F of the accommodating portion 30 is blocked by the reflective portion 43B having such an arrangement. Furthermore, the other end side of the light source unit 21 is fixed by being screwed to the frame 23 with screws SC.

  The operation of removing the light source unit 21 from the housing unit 30 is performed in the reverse procedure described above.

  The light source unit 21 accommodated in the accommodating portion 30 is positioned at a predetermined position by engagement between the convex portion 25X of the back cover 25 and the reflecting portion 43B, insertion of the insertion portion 43E into the recess 30A, or the like. Further, in a state where the light source unit 21 is housed in the housing portion 30, the screw SC is screwed to the frame 23, so that the light source unit 21 is fixed to the frame 23 while being positioned in the housing portion 30. The

  Thus, in the state where the light source unit 21 is accommodated in the accommodating portion 30, the light emitting surface 41E of the light emitting diode 41 faces the one end surface 22c of the light guide plate 22 and the heat radiating member 43 of the heat radiating member 43 as shown in FIG. The reflection part 43 </ b> B covers the accommodation part 30.

  At this time, the support portion 43 </ b> A and the reflection portion 43 </ b> C of the heat dissipation member 43 are in contact with the frame 23 to position the light source unit 21.

  At this time, the light emitting surface 41E of the light emitting diode 41 is preferably separated from the one end surface 22c of the light guide plate 22. In other words, since the light emitting diode 41 is a heat generation source, if it is in contact with the light guide plate 22, there is a possibility that problems such as deformation of the light guide plate 22 occur due to the influence of the heat. In this embodiment, since the light source unit 21 is positioned in a state where the light source unit 21 is housed in the housing portion 30, it is not necessary to place the light emitting diode 41 and the light guide plate 22 in contact with each other.

  According to such a configuration, in the light source unit 21, the film substrate 42 on which the plurality of light emitting diodes 41 that are heat sources are mounted is bonded to the heat radiating member 43 with the heat radiating adhesive tape 44. Heat generated by the diode 41 can be released from the film substrate 42 to the heat radiating member 43 via the adhesive tape 44. In particular, since the film substrate 42 is bonded to the support portion 43A without air functioning as a heat insulating material, the heat from the light emitting diode 41 can be directly released from the film substrate 42 to the heat radiating member 43. Efficiency can be improved.

  Therefore, the light emitting diode 41 can be driven in a relatively low temperature environment, and the life of the light emitting diode 41 can be extended.

  Further, the heat radiating member 43 is in contact with the back cover 25 in a state where the light source unit 21 is accommodated in the accommodating portion 30. The back cover 25 is formed of a heat-dissipating metal material or the like, and heat generated by the light emitting diode 41 can be released from the heat dissipation member 43 of the light source unit 21 to the back cover 25 further. Thus, by adding the back cover 25 to the heat dissipation path, the heat capacity is increased and the heat dissipation efficiency can be further improved as compared with the case of the heat dissipation member 43 alone.

  Further, in a state where the light source unit 21 is accommodated in the accommodating portion 30, the reflecting portion 43B forms an exterior of the backlight unit 15 and is exposed to the atmosphere. Similarly, the back cover 25 forms the exterior of the backlight unit 15 and is exposed to the atmosphere. For this reason, it becomes possible to improve heat dissipation efficiency more.

  In addition, a convex portion 43X extending along the extending direction is formed on the reflecting portion 43B constituting the light source unit 21. Thereby, even if the heat radiating member 43 is formed of a relatively thin metal material for weight reduction or the like, the rigidity of the light source unit 21 can be improved.

  For this reason, generation | occurrence | production of the curvature along the extension direction of the light source unit 21 can be suppressed. Moreover, the deformation of the reflecting portion 43B can be prevented, the adhesion to the back cover 25 can be improved, heat transfer to the back cover 25 can be promoted, and light leakage from the back cover 25 can be suppressed. It is also possible to do.

  In addition, the surface area of the reflective portion 43B can be increased by the convex portion 43X. Since the reflection part 43B forms the exterior, the heat radiation efficiency can be further improved by increasing the surface area exposed to the atmosphere.

  On the other hand, when the light source unit 21 needs to be replaced, for example, when the light emitting diode 41 is deteriorated, the light source unit 21 is removed from the housing portion after removing the screw SC as shown in FIGS. 30 can be extracted from the back surface of the liquid crystal display device 1 (that is, the back surface of the backlight unit) (back surface extraction method). As a result, the light source unit 21 can be easily replaced in units.

  The adhesive tape 44 applied in this embodiment is desirably formed so that its width (that is, the length along the third direction D3) is equal to or greater than the width of the film substrate 42.

  That is, when the width of the adhesive tape 44 is equal to the film substrate 42 (3 mm) and when the width of the adhesive tape 44 is smaller than the width of the film substrate 42 (1 mm), the temperature rise value of the light emitting diode 41 is changed. Compared. FIG. 7 shows a comparison result of temperature rise values for each tape width.

  Here, the difference between the temperature of the light-emitting diode 41 before driving and the temperature of the light-emitting diode 41 after a stable passage of 2 hours after supplying a predetermined amount of current to the light-emitting diode 41 is defined as a temperature rise value.

  When the width of the adhesive tape 44 is 1 mm, the temperature rise value is 34.9 ° C. when a current of 75 mA is supplied to the light emitting diode 41, and the temperature rise value is when the current of 150 mA is supplied to the light emitting diode 41. It was 79.6 ° C.

  On the other hand, when the width of the adhesive tape 44 is 3 mm, the temperature rise value is 22.8 ° C. when a current of 75 mA is supplied to the light emitting diode 41, and a current of 150 mA is supplied to the light emitting diode 41. Sometimes the temperature rise was 54.9 ° C.

  As described above, when the width of the adhesive tape 44 is smaller than the width of the film substrate 42, the heat path escaping from the film substrate 42 to the heat radiating member 43 is reduced, and the film is not provided in the portion where the adhesive tape 44 is not interposed. Since an air layer is interposed between the substrate 42 and the heat dissipation member 43 for heat insulation, a sufficient heat dissipation effect cannot be obtained and the temperature of the light emitting diode 41 is increased.

  Therefore, it is desirable to apply the adhesive tape 44 whose width is equal to or greater than the width of the film substrate 42. Thereby, the film substrate 42 can adhere | attach the whole surface of the surface on the opposite side to the surface in which the light emitting diode 41 was mounted to the heat radiating member 43. FIG. Therefore, it is possible to ensure a sufficient heat path without an air layer interposed between the film substrate 42 and the heat dissipation member 43.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the spirit of the invention in the stage of implementation. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

  The transmissive liquid crystal display panel described in the above-described embodiment has a transmissive display function that selectively transmits illumination light from the backlight unit 15 in at least a part of the active area 6. Any configuration may be used, and a transflective liquid crystal display panel in which each pixel has a reflective portion and a transmissive portion is also included.

FIG. 1 is an exploded perspective view schematically showing the structure of a liquid crystal display device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing a structure including the light source unit of the backlight unit in the liquid crystal display device shown in FIG. FIG. 3 is a perspective view schematically showing the structure of the light source unit shown in FIG. FIG. 4 is a cross-sectional view schematically showing the structure when the light source unit shown in FIG. 3 is cut along line AA. FIG. 5 is a cross-sectional view for explaining a state in which the light source unit is attached and detached from the back side in the liquid crystal display device shown in FIG. FIG. 6 is a diagram for explaining a situation when the light source unit is attached / detached from the back side of the liquid crystal display device. FIG. 7 is a diagram showing a comparison result of temperature rise values of the light emitting diodes depending on the width of the adhesive tape.

Explanation of symbols

PX: Pixel 1 ... Liquid crystal display device 2 ... Liquid crystal display panel 3 ... Array substrate 4 ... Counter substrate 5 ... Liquid crystal layer 15 ... Backlight unit (illumination unit)
DESCRIPTION OF SYMBOLS 21 ... Light source unit 22 ... Light guide plate 23 ... Frame 25 ... Back cover 25X ... Convex part 26 ... Optical sheet 30 ... Accommodating part 30F ... Opening part 30A ... Recessed part 30B ... Screw hole 41 ... Light emitting diode 41E ... Light emitting surface 42 ... Film Substrate 43 ... Heat dissipation member 43A ... Support portion 43B ... Reflecting portion 43E ... Insertion portion 43X ... Convex portion 44 ... Adhesive tape

Claims (8)

A light guide plate;
A frame for holding the light guide plate and forming an accommodating portion apart from one end surface of the light guide plate;
A light source unit housed in the housing portion,
The housing is configured to be detachable from the light source unit,
The light source unit includes: a light emitting diode having a light emitting surface that is substantially parallel to a mounting surface; a film substrate on which a plurality of the light emitting diodes are mounted side by side in a first direction; a support unit that supports the film substrate; A heat-dissipating member having a reflecting portion extending in a second direction orthogonal to the first direction from a support portion; and an adhesive tape that adheres the film substrate to the support portion and has a heat dissipation property; In the state accommodated in the illumination unit, the light emission surface of the light emitting diode opposes the one end surface of the light guide plate, and the reflection part of the heat dissipation member covers the accommodation part.   The lighting unit according to claim 1, wherein the adhesive tape has a width equal to or greater than a width of the film substrate.   The lighting unit according to claim 1, wherein the heat radiating member is made of a metal material.   The lighting unit according to claim 1, wherein the reflection portion of the heat radiating member has a convex portion extending in the first direction.   2. The illumination according to claim 1, wherein the heat radiating member includes an insertion portion on one end side along the first direction, and the other end side along the first direction is screwed to the frame. unit.   The lighting unit according to claim 1, wherein the reflection portion of the heat radiating member forms an exterior of the lighting unit.   The lighting unit according to claim 1, wherein a light emitting surface of the light emitting diode is separated from one end surface of the light guide plate. A liquid crystal display panel holding a liquid crystal layer between a pair of substrates;
An illumination unit that is disposed on the liquid crystal display panel and illuminates the liquid crystal display panel,
The lighting unit is:
A light guide plate;
A frame for holding the liquid crystal display panel and the light guide plate and forming an accommodating portion apart from one end surface of the light guide plate;
A light source unit housed in the housing portion,
The housing is configured to be detachable from the light source unit,
The light source unit includes: a light emitting diode having a light emitting surface that is substantially parallel to a mounting surface; a film substrate on which a plurality of the light emitting diodes are mounted side by side in a first direction; a support unit that supports the film substrate; A heat-dissipating member having a reflecting portion extending in a second direction orthogonal to the first direction from a support portion; and an adhesive tape that adheres the film substrate to the support portion and has a heat dissipation property; The light emitting surface of the light emitting diode faces the one end surface of the light guide plate in the state of being housed in the liquid crystal display device, and the reflective portion of the heat dissipation member covers the housing portion.

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