JP4802747B2 - Display device - Google Patents

Description

  The present invention relates to a display device having a backlight assembly, and more particularly to a backlight assembly capable of reducing noise generation and a display device including the backlight assembly.

  In general, a liquid crystal display device includes a display unit that displays an image and a backlight assembly that generates and provides light to the display unit. The backlight assembly includes a light guide plate that guides light from the light source to the display unit, a frame that stores the light guide plate, and a housing that stores these members. The light source includes, for example, a light emitting diode and a mounting substrate that supplies power to the arranged light emitting diode.

  The light guide plate has a flat plate shape with a light emission observation surface, and allows light emitted from the light source to enter the inside of the light guide plate from one side surface of the light guide plate. Then, the light incident on the inside of the light guide plate is emitted from the light emission observation surface of the light guide plate with the traveling direction changed.

  The frame body accommodates the light guide plate in a space formed by a bottom surface of the opening and a side wall extending from the bottom surface. The light source is housed between the side wall of the frame and the side wall of the housing with the light emitting surface facing one side of the light guide plate.

JP-A-2005-123171.

  However, when an impact or heat is applied from the outside with the frame housed in the housing, the frame body or the light guide plate is moved by the impact or heat, or its shape is deformed and the frame body is moved to the housing. Contact. Further, the frame body moves through the gap between the frame body and the housing, and the collision sound and friction sound become noise. In particular, when the display device is used for a portable product, the display device is not fixed at a fixed position and moves by the movement of the wearer. By such movement of the display device, there is a high possibility that the frame body and the housing collide with each other, and the collision sound becomes noise from the display device.

  The backlight assembly disclosed in Japanese Patent Application Laid-Open No. 2005-123171 reduces noise by varying the gap between the light guide plate and the frame at a predetermined portion. Thereby, although the noise by the collision with a frame and a light-guide plate can be reduced, the noise by the collision with a frame and a housing | casing cannot be reduced. Therefore, the backlight assembly cannot sufficiently suppress the generation of noise as the entire backlight assembly.

  Therefore, an object of the present invention is to provide a backlight assembly in which noise is further reduced.

  To achieve the above object, a display device according to the present invention contains a light source, a light guide that guides light from the light source, and a frame that has an opening that contains the light guide. And a space between the outer wall surface of the side wall of the frame body and the inner wall surface of the housing is smaller than the corner portion of the frame body at the central portion provided between the corner portions. It is characterized by that.

  It is preferable that the outer wall surface of the side wall of the frame is curved from the corner to the center. Or it is preferable that the outer wall surface of the side wall of the said frame has a convex part between the said corner | angular parts.

  The present invention can provide a backlight assembly that can reduce noise generation.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, the form shown below exemplifies a display device for embodying the technical idea of the present invention, and the present invention does not limit the display device to the following.

  Further, the present specification by no means specifies the members shown in the claims to the members of the embodiments. The dimensions, materials, shapes, relative arrangements, and the like of the components described in the embodiments are not intended to limit the scope of the present invention only to the description unless otherwise specified. It's just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Further, in the following description, the same name and reference sign indicate the same or the same members, and detailed description will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing.

  A display device including a light source, a light guide that guides light from the light source, a frame that has an opening that accommodates the light guide, and a housing that has a recess that accommodates the housing. In order to reduce noise caused by the frame, the present inventors have made various studies. As a result, the problem is solved by the fact that the distance between the outer wall surface of the side wall of the frame body and the inner wall surface of the housing is smaller in the central portion between the corner portions than in the corner portions of the frame body. It came to do.

  FIG. 1 is a perspective view showing a backlight assembly of the present embodiment, and FIG. 2 is a plan view of the backlight assembly shown in FIG. Hereinafter, the backlight assembly of this embodiment will be described with reference to the drawings.

  As shown in FIGS. 1 and 2, the backlight assembly of the present embodiment includes a light guide plate 100 that guides light from a light source in a predetermined direction, a frame body 200 having an opening that accommodates the light guide plate 100, and And a housing 300 having a recess for housing them. The backlight assembly of this embodiment is further provided with a display device by including a light source that generates light.

  The light guide in the backlight assembly of this embodiment includes the first to fourth side surfaces 101, 102, 103, and 104, and the reflection extending from one end side of the first to fourth side surfaces 101, 102, 103, and 104. The light guide plate 100 includes a surface 105 and an emission surface 106 that extends from the other end of the first to fourth side surfaces 101, 102, 103, and 104 and faces the reflective surface 105.

  Here, at least one of the first to fourth side surfaces 101, 102, 103, 104 faces the light emitting surface of the light source, and is an incident surface for introducing light from the light source into the light guide plate. is there. The reflection surface 105 reflects light incident on the side surface toward the emission surface 106, and the emission surface 106 emits light incident on the side surface and guided through the light guide plate. The light source includes a light emitting member that generates light and a mounting substrate on which the light emitting member is mounted.

  As shown in FIGS. 1 and 3, the frame body 200 is a frame-like member having an opening having a size that can accommodate the light guide plate 100. That is, it includes first to fourth side walls 201w, 202w, 203w, and 204w that extend from the bottom surface and the bottom surface to form an accommodation space for the light guide plate 100. Further, the frame includes a first corner (C1) where the first side wall 201w and the second side wall 202w are in contact, a second corner (C2) where the second side wall 202w and the third side wall 203w are in contact, and a third side wall 203w. And a fourth corner (C4) with which the fourth side wall 204w and the first side wall 201w are in contact with each other.

  Further, the frame body 200 has a first central portion (D1) between the first corner (C1) and the fourth corner (C4), and the first corner (C1) and the second corner ( 2nd center part (D2) between C2). Further, a third central portion (D3) is provided between the second corner portion (C2) and the third corner portion (C3), and between the third corner portion (C3) and the fourth corner portion (C4). Has a fourth central portion (D4). Note that the “center portion” in the frame body of the present embodiment is the portion having the maximum thickness, where the distance between the inner wall surface of the side wall forming the opening and the outer wall surface on the opposite side is the thickness of the side wall.

  In this embodiment, the distance between the first to fourth outer wall surfaces 201, 202, 203, and 204 of the side wall of the frame and the first to fourth inner wall surfaces 301, 302, 303, and 304 of the recess of the housing is determined by the frame body. The central portion (D1 to D4) is smaller than the corner portions (C1 to C4). Such a frame can be formed by bending the central portion of the side wall having the same thickness at the corner portion and the central portion so as to be convex toward the inner wall surface side of the housing. The thickness of the side wall of the body can be made different between the corner and the center. About the frame by the latter, since it is easy to fit with a light guide plate and the position shift of a light guide plate and a frame is suppressed, it can be set as a reliable backlight assembly compared with the frame by the former. In the backlight assembly of this embodiment, the latter frame will be described.

  That is, in the frame of this embodiment, the thickness of the first to fourth side walls in the first to fourth corners (C1 to C4) is t1, and the first to third central portions (D1 to D3) are the first. If the thickness of the third side wall is t2, the thickness t2 is larger than the thickness t1. Here, the thicknesses (t1, t2) of the first to fourth side walls are the outer surfaces facing the inner wall surface of the first to fourth side walls forming the opening of the frame and the inner wall surface of the housing. It is defined by the distance from the wall.

  In this embodiment, the thicknesses (t1, t2) of the first to fourth side walls are set as described above for all the side walls from the first side wall to the fourth side wall of the frame. Thus, if it sets about all the side walls, fitting with a frame and a housing | casing will become firm, but you may set about predetermined | prescribed side walls as needed. For example, the thickness of the side wall on the side where the light source is disposed may be set as described above for the other side walls without setting the wall thickness as described above. Of the first side wall to the fourth side wall, the side wall corresponding to the side surface on which the light of the light guide plate is incident has a groove-shaped recess opened toward the light source side, and the light source is accommodated therein. Yes.

  When the frame body 200 of this embodiment is accommodated in the housing 300, a space capable of receiving shape deformation and displacement of the frame body is formed in the first to fourth corners (C1 to C4) of the frame body 200. The On the other hand, there is almost no such space in the first to third central portions (D1 to D3). For example, in the first to fourth corners (C1 to C4), the outer wall surface of the first to fourth side walls is the first distance (d1) with respect to the first to fourth inner wall surfaces that form the recesses of the housing. ). On the other hand, in the first to third central portions (D1 to D3), the outer wall surfaces of the first to fourth side walls are separated from the first to fourth inner wall surfaces of the housing by the second distance (d2). The Here, the first distance (d1) is larger than the second distance (d2). Therefore, the frame and the housing are more firmly fixed in the first to fourth central portions (D1 to D4) than in the first to fourth corner portions (C1 to C4). Therefore, the generation of noise due to frictional noise and collision due to the movement of the frame within the recess of the housing is reduced.

  As shown in FIG. 2, the light guide plate 100 is accommodated in the accommodation space formed by the opening of the frame body 200. At this time, the inner wall surfaces of the first to fourth side walls 201w, 202w, 203w, and 204w that form the opening face the first to fourth side surfaces 101, 102, 103, and 104 of the light guide plate 100, respectively.

  As described above, the first to fourth outer wall surfaces 201, 202, 203, 204 of the first to fourth side walls 201 w, 202 w, 203 w, and 204 w of the frame body 200 and the first to fourth inner wall surfaces 301 of the housing 300 are used. , 302, 303, and 304 are made smaller in the central portions (D1 to D4) between the corner portions (C1 to C4) than the corner portions (C1 to C4) of the frame body 200. The thickness of the side wall is made different between the corner and the center.

  Furthermore, as specific shapes of the first to fourth outer wall surfaces 201, 202, 203, and 204 of the frame body 200, the first to fourth outer wall surfaces 201, 202, 203, and 204 have corner portions (C1 to C4). It is preferable that the center part provided between these is a convex part protruding toward the inner wall surface of the housing.

  Alternatively, the first to fourth outer wall surfaces 201, 202, 203, and 204 are curved surfaces that are continuously curved from the corners (C1 to C4) to the center (D1 to D4) toward the inner wall surface of the housing. It is preferable. By setting it as such a curved surface, even if it contacts the inner wall surface of a housing | casing in a center part and a frame deform | transforms in the direction of a housing | casing by thermal expansion, a contact area can further be increased in the periphery of a center part. Therefore, the fitting between the housing and the frame can be further strengthened, and noise due to the housing and the frame can be reduced. Further, in this embodiment, the relationship between the frame body and the housing is the above-described configuration when viewed from the top surface shown in FIG. 3, but the cross-section of the side wall of the frame body is not limited to the above-described configuration. The relationship with the body may be the above-described configuration. That is, when the cross section of the side wall of the frame body is taken along a plane perpendicular to the upper surface shown in FIG. 3, the distance from the inner wall surface of the housing is smaller at the center than at the corner of the cross section. Good. Hereinafter, each structure of the backlight assembly of this form is explained in full detail.

(Frame)
The frame body 200 in this embodiment is arranged with respect to the housing 300 and the light guide plate 100. The shape of the frame body 200 is various shapes according to the shapes of the housing 300 and the light guide plate 100. As shown in the figure, the frame body 200 in this embodiment has at least a recess or a through hole having an opening that can accommodate the light guide plate 100. The size and shape of the recess or the through hole are appropriately adjusted according to the size, shape and number of the light guide plate 100 to be accommodated. The thickness of the side wall forming the opening of the frame body 200 is smaller than the size of the gap formed by the side surface of the light guide plate 100 and the inner wall surface of the recess of the housing 300. As a result, the frame body 200 is fitted into the gap formed by the side surface of the light guide plate 100 and the inner wall surface of the recess of the housing 300, and the light guide plate 100 and the frame body 200 are accommodated in the recess of the housing 300. be able to.

  In the backlight assembly according to this embodiment, the light emitting surface and the incident surface of the light emitting member are opposed to each other by a frame that is in contact with the side surface that is the incident surface of the light guide plate.

  The frame preferably has a light diffusing agent such as calcium carbonate, aluminum oxide or titanium oxide or a white pigment at least on the inner wall surface of the side wall. Such a side wall portion of the frame can reflect the light from the light emitting member in the direction of the incident surface of the light guide.

  As the frame material, a material having lower thermal conductivity than the material of the mounting substrate is selected. For example, an insulating material such as polycarbonate, polyether ether ketone, or fluorine-based resin having excellent mechanical strength can be used. Furthermore, the frame can be formed by injection molding with a resin material containing a light diffusing agent such as calcium carbonate, aluminum oxide, or titanium oxide.

(Light emitting member)
The light emitting member in this embodiment refers to a light source that emits light that can be incident on a light guide, such as a semiconductor light emitting element such as a light emitting diode or a semiconductor laser, a cold cathode ray tube, or a light source that is selected and combined variously. In this specification, although a light emitting diode is demonstrated, it is not limited to this. The light emitting diode can be variously selected depending on the dominant wavelength of light emitted from the semiconductor layer. In particular, a light-emitting diode that emits white mixed light is preferably used. Such light emitting diodes include a combination of light emitting diodes that emit RGB colors, a light emitting diode including a semiconductor light emitting element, and a phosphor that emits light excited by light emitted from the semiconductor light emitting element. There are various types. A semiconductor light emitting device capable of emitting blue light can emit light with high brightness by using, for example, a gallium nitride compound semiconductor.

  In addition, the light emitting diode in this embodiment includes a package having a recess. The electrode exposed in the recess and the LED chip disposed in the recess are electrically connected by a conductive wire such as a gold wire or a conductive paste such as an Ag-containing epoxy resin. A surface mount type light emitting diode sealed with a light transmitting resin such as an epoxy resin is formed in the package.

  The package used in this embodiment is preferably one in which an LED chip can be disposed at the bottom of the recess, and various resins such as epoxy resin, silicone resin, acrylic resin, PBT (polybutylene terephthalate), liquid crystal polymer, and aromatic nylon are used. And is preferably formed.

  The package can be a ceramic package obtained by laminating and firing ceramic green sheets. Since the ceramic package is superior in heat resistance and light resistance as compared to a package made of a resin material, a high-output and highly reliable semiconductor light-emitting device can be obtained.

  The package is preferably filled with an LED chip and a translucent resin electrically connected to the lead electrode. Here, the translucent resin that covers the LED chip may contain a fluorescent material as necessary.

The fluorescent material used in the present embodiment converts the wavelength of the LED chip light. That is, the fluorescent material absorbs at least a part of the light of the LED chip and emits light having a different wavelength. Here, the phosphor is preferably a phosphor that converts light from the LED chip to a longer wavelength side. In the case where the light from the LED chip is high-energy short-wavelength visible light, perylene derivatives that are organic phosphors, ZnCdS: Cu, and YAG: Ce that is a kind of aluminum oxide phosphor (for example, YAlO ₃ : Ce). , Y ₃ Al ₅ O ₁₂ : Ce), and inorganic phosphors such as nitrogen-containing CaO—Al ₂ O ₃ —SiO ₂ activated by Eu and / or Cr. In particular, the YAG: Ce phosphor absorbs part of the blue light from the LED chip depending on its content and emits yellow light that is a complementary color. Can be formed relatively easily.

(Mounting board)
The mounting substrate is for mounting, fixing and arranging the light emitting member, and is provided with conductor wiring for supplying power to the light emitting member. For example, it can be suitably formed by a glass epoxy substrate on which a conductive pattern made of copper foil or the like is formed, or a metal body bonded with an insulating resin. Or it can be set as the board | substrate with high heat dissipation by which conductor wiring was given to the metal material which consists of aluminum and copper via the insulating material. In this embodiment, in order to apply the elastic force from the elastic member uniformly to the substrate, a material having a relatively high strength is preferable, and a plate material made of a metal material is preferable. Moreover, it is preferable that a mounting board | substrate is closely_contact | adhered and arrange | positioned through a heat conductive member like a heat dissipation sheet.

(Light guide)
The light guide in this embodiment can guide the light from the light emitting member incident from a part of the end surface by utilizing the internal reflection, and can emit light in a desired shape from a predetermined light emitting surface. Is. Therefore, depending on the desired shape of the light emitting surface, various shapes such as a needle shape of a meter needle and a plate shape usable as a liquid crystal backlight light source can be taken. The light guide has translucency in order to efficiently emit light from the light emitting diode or light obtained by wavelength conversion of the light from the light emitting surface. As a material for such a light guide, various materials such as acrylic resin, epoxy resin, and glass are preferably exemplified.

(Casing)
The housing in this embodiment is a member that has a recess that accommodates at least a substrate on which a light emitting member is disposed, a frame body, and a light guide, and holds those members. As shown in FIG. 1, the housing 300 in this embodiment has a recess formed by first to fourth inner wall surfaces 301, 302, 303, and 304.

  As the case, various types such as resins and metals containing various light diffusing agents are preferably mentioned. In particular, in consideration of heat dissipation and light reflection of a light emitting diode that generates heat, metals such as nickel, iron, copper, and aluminum, and various alloys such as stainless steel are more preferably used. The size and shape of the housing can be variously selected according to the size and shape of the light guide, the light emitting diode, and the substrate.

  As described above, both the frame body and the light guide plate are often made of resin in consideration of moldability, while the casing is often made of metal in consideration of mechanical strength. . Both the frame body and light guide plate made of resin are easy to fit, but the frame body made of resin and the housing made of metal are difficult to fit. Therefore, it is considered that the noise generated by the frame and the housing is larger than the noise caused by the frame and the light guide plate. Therefore, in order to reduce the noise of the entire backlight assembly, it is necessary to make the fitting between the frame body and the housing stronger than the fitting between the light guide plate and the frame body. Since the backlight assembly of the present embodiment has a strong fit between the frame and the housing, noise of the entire backlight assembly can be reduced as compared with a conventional backlight assembly.

  Examples according to the present invention will be described in detail below. Needless to say, the present invention is not limited to the following examples.

  The backlight assembly of the present embodiment includes a light guide plate that guides light from a light source in a predetermined direction, a frame having an opening that accommodates the light guide plate, and a housing having a recess that accommodates them. . Further, a light emitting diode is disposed as a light source in the backlight assembly in the present embodiment to form a display device. FIG. 1 is a schematic perspective view of a backlight assembly in the present embodiment. FIG. 2 is a schematic top view of the backlight assembly in the present embodiment. FIG. 3 is a schematic top view of a frame body in the backlight assembly of the present embodiment. The backlight assembly in the present embodiment will be described below with reference to the drawings.

  As shown in FIGS. 2 and 3, the frame body 200 in this embodiment has an opening formed by a bottom surface and first to fourth side walls 201 w, 202 w, 203 w, 204 w extending in a direction perpendicular to the bottom surface. Have The first to fourth side walls 201w, 202w, 203w, 204w have a first thickness (t1) at the first to fourth corners (C1 to C4), and the first to fourth side walls 201w, 202w, 203w. , 204w has a second thickness (t2) greater than the first thickness (t1) at the center (D1 to D4). In the present embodiment, the first thickness (t1) is 0.60 mm, and the second thickness (t2) is 0.90 mm. Moreover, the shape of the opening part of a frame is a rectangle, and the magnitude | size is 86.25 mm in length and 160.35 mm in width.

  The light guide in this embodiment is a plate-shaped light guide plate formed by injection molding of acrylic resin, and includes first to fourth side surfaces 101, 102, 103, and 104, and first to fourth side surfaces 101 thereof. , 102, 103, 104 and a reflecting surface 105 extending from one end side, and an exit surface 106 extending from the other end side of the first to fourth side surfaces 101, 102, 103, 104 and facing the reflecting surface 105. .

  The fourth side wall 204w of the frame body 200 facing the fourth side surface 104 of the light guide plate 100 is provided with a recess for housing the light emitting diode (not shown). The fourth side wall 204w has a shape that fits to a light emitting diode or a mounting substrate on which the light emitting diode is mounted. The fourth side surface 104 of the light guide plate 100 faces the light emitting surface of the light emitting diode, and introduces light emitted from the light emitting diode into the light guide plate 100.

  As shown in FIGS. 1 and 2, in the first corner (C1) of the frame body 200, the outer wall surface 201 of the first side wall 201w is the inner wall surface of the recess of the housing 300 that faces the outer wall surface 201. 301 is separated by a first distance (d1). Similarly, in the second corner portion (C2) adjacent to the first corner portion (C1) of the frame body, the outer wall surface 202 of the second side wall 202w is the inner wall of the casing 300 that the outer wall surface 202 faces. The wall surface 302 is separated by a first distance (d1).

  On the other hand, in the second central portion (D2) sandwiched between the first corner portion (C1) and the second corner portion (C2), the outer wall surface 202 of the second side wall 202w of the frame body 200 faces the outer wall surface 202. The second distance (d2) (≈0) is separated from the inner wall surface 302 of the casing. Here, the first distance (d1) is larger than the second distance (d2).

  The outer wall surfaces 201, 202, 203, and 204 of the first to third side walls have gentle curved surfaces from the first to fourth corners (C1 to C4) to the central portion provided therebetween. This curved surface is a curved surface convex toward the inner wall surface of the housing in the first to third central portions (D1 to D3). For example, the outer wall surface 202 of the second side wall 202w of the frame body 200 has a predetermined curvature from the first corner (C1) to the second corner (C2) with the second central portion (D2) interposed therebetween. The curved surface is continuously curved.

  When the frame is housed in the housing, the distance between the first to third side walls and the first to third inner wall surfaces of the housing in the first to fourth corners (C1 to C4) of the frame. It is ensured more widely in the first to third central portions (D1 to D3). That is, in the first to fourth corners (C1 to C4), a space that can accept a change in the position of the frame due to deformation or movement of the shape of the frame is formed. The frame and the housing are in contact with each other at the center of the housing, and even if the frame or the light guide plate is deformed by thermal expansion, the frame and the housing can be firmly fixed.

  In the backlight assembly in the present embodiment, the distance between the frame body and the inner wall surface of the housing is minimized in the first to third central portions (D1 to D3) of the side wall of the frame body. As a result, the frame body and the housing are firmly fixed, so that the frame body does not move in the housing, and the generation of noise due to frictional sound or collision sound can be reduced.

  INDUSTRIAL APPLICABILITY The present invention can be used as a planar light source such as a liquid crystal backlight as a semiconductor light-emitting device that is resistant to vibration and is thinned, miniaturized, and reduced in power consumption.

FIG. 1 is a schematic perspective view of a backlight assembly according to an embodiment of the present invention. FIG. 2 is a schematic top view of a backlight assembly in one embodiment of the present invention. FIG. 3 is a schematic top view of a frame body according to an embodiment of the present invention.

Explanation of symbols

100: Light guide plates 101, 102, 103, 104: First to fourth side surfaces 200 of the light guide plate ... Frame bodies 201, 202, 203, 204 ... First to fourth outside of the frame body Wall surface 201w, 202w, 203w, 204w ... 1st thru | or 4th side wall 300 ... frame 301, 302, 303, 304 ... 1st-4th inner wall surface of a housing | casing

Claims (3)

  A side wall of the frame, comprising: a light source; a light guide for guiding light from the light source; and a frame having an opening for receiving the light guide; The display device is characterized in that the distance between the outer wall surface of the frame and the inner wall surface of the housing is smaller in the central portion provided between the corner portions than in the corner portions of the frame body.   The display device according to claim 1, wherein an outer wall surface of the side wall of the frame body is curved from the corner portion to the central portion. The display device according to claim 1, wherein an outer wall surface of a side wall of the frame body has a convex portion between the corner portions.

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