JP2010078624A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device that suppresses noise and shavings even when vibrations are applied, by surely holding a diffusion plate in a cell case. <P>SOLUTION: The liquid crystal display device includes: a liquid crystal display panel 1; a sheet-like diffusion plate 2 disposed at the rear of the liquid crystal display panel 1 and having a projecting piece 21 at the edge thereof; a cell case 3 where the liquid crystal display panel 1 and the diffusion plate 2 are held; and a light emitting diode 4 for illuminating the liquid crystal display panel 1 and the diffusion plate 2 from the rear. The side wall 31 of the call case 3 is provided with a groove hole 35 through which the projecting piece 21 is inserted, and a projection 342 projecting in such a direction that the groove hole 35 is narrowed, is provided at the outside of the side wall 31 corresponding to the groove hole 35. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid crystal display panel and a liquid crystal display device including a diffusion plate behind the liquid crystal display panel.

  In a liquid crystal display panel and a liquid crystal display device provided with a diffusion plate behind the liquid crystal display panel, when the liquid crystal display device is vibrated, the diffusion plate is shaken to suppress generation of abnormal noise and abrasion powder. For example, Patent Document 1 or Patent Document 2 is available. In the liquid crystal display device of Patent Document 1, a positioning hole 53 is provided in the peripheral wall 51 of the holder 5 (corresponding to the cell case of the present application), and a protrusion 54 is provided on the inner surface of the positioning hole 53. Further, the rear plate 2 (corresponding to the diffusion plate) is provided with positioning ears 2A. When the positioning ears 2A are inserted into the positioning holes 53, they are provided on the inner surface portions of the positioning holes 53. The projection 54 partially presses the positioning ear 2A so that the back plate 2 is held without moving with respect to the holder 5 even if vibration is applied.

In the liquid crystal display device of Patent Document 2, a through hole 23 is provided in the transflective plate 2 (corresponding to the diffusion plate of the present application), and the through hole 23 is provided on a locking pin 20 provided in the holder 1 (corresponding to the cell case). The point to push in is described. Then, the translucent plate 2 is press-fitted into the locking pin 20 and positioned and fixed to the holder 1, and the inner diameter of the through hole 23 is slightly smaller than the outer diameter of the locking pin 20.
JP 2008-89660 A JP 2001-281638 A

  However, in the liquid crystal display device of Patent Document 1, the size (gap) of the positioning hole 53 of the holder 5 into which the positioning ear 2A provided on the back plate 2 is inserted and the thickness of the back plate 2 itself. There is a possibility that the projection 54 does not press the positioning ear 2A due to the dimensional variation. Then, when vibration is applied to the liquid crystal display device, there is a risk that the back plate 2 will rattle and generate abnormal noise or rubbing powder. In order to eliminate such a point, if the height of the protrusion 54 is set high so that the protrusion 54 is surely in contact with the positioning ear 2A even if dimensional variation occurs, the gap between the positioning holes 53 If the dimensions vary in the direction of narrowing, the positioning ear 2A may not be inserted into the positioning hole 53.

  Further, in the liquid crystal display device of Patent Document 2, when the inner diameter dimension of the through hole 23 varies toward the larger one and the outer dimension of the locking pin 20 varies toward the smaller outer diameter, the through hole is smaller than the diameter of the locking pin 20. There is a possibility that the diameter of 23 will become large and it will not be press-fitted and fixed, which may lead to the generation of abnormal noise and rubbing powder. Conversely, if the diameter of the locking pin 20 is too larger than the diameter of the through hole 23, it may be difficult to insert the locking pin 20 into the through hole 23, or the insertion may not be possible. In both Patent Documents 1 and 2, so-called dimension management is difficult.

  The present invention has been made in view of the above points, and a liquid crystal display device capable of suppressing generation of abnormal noise and rubbing powder even when vibration is applied by reliably holding a diffusion plate in a cell case. The purpose is to provide.

  In order to achieve the above object, the present invention holds a liquid crystal display panel, a sheet-like diffusion plate disposed behind the liquid crystal display panel and having a protruding piece at an edge, the liquid crystal display panel, and the diffusion plate. A cell case, and a light source for illuminating the liquid crystal display panel and the diffusion plate from behind, and a groove hole through which the protruding piece is inserted is provided in the side wall of the cell case, and the side wall corresponding to the groove hole is provided. Protrusions projecting in the direction of narrowing the slot are provided on the outside.

  Further, the projection is provided at a position corresponding to the lower side of the slot.

  Further, an inclined surface facing the groove hole side is provided on the tip side of the protrusion.

  The cell case is provided with a holding piece for locking the upper surface of the edge of the diffusion plate.

  By securely holding the diffusion plate in the cell case, it is possible to obtain a liquid crystal display device capable of suppressing the generation of abnormal noise and rubbing powder even when vibration is applied.

  FIG. 1 is an exploded perspective view of a liquid crystal display device showing an embodiment of the present invention. 2 is a cross-sectional view of the liquid crystal display device showing the AA direction in FIG. 1, and FIG. 3 is a cross-sectional view of the liquid crystal display device showing the BB direction in FIG. FIG. 4 is a cross-sectional view of the main part of the cell case where the diffusion plate is held. FIG. 5 is a cross-sectional view of the main part of the cell case showing a state in which the diffusion plate is held. FIG. 6 is a cross-sectional view of a main part showing a state where the upper surface of the edge of the diffusion plate is locked.

  The liquid crystal display device includes a transmissive liquid crystal display panel 1, a sheet-like diffusion plate 2 disposed behind the liquid crystal display panel 1, a cell case 3 in which the liquid crystal display panel 1 and the diffusion plate 2 are held, A rigid circuit board mounted behind the cell case 3 and mounted with a light emitting diode 4 as a light source for illuminating the liquid crystal display panel 1 and the diffusion plate 2 from the back, a circuit (not shown) for driving the liquid crystal display panel 1, and the like 5, a conductive rubber 6 as a current-carrying member that electrically connects the liquid crystal display panel 1 and the circuit board 5, and a metal pressing frame for fixing the liquid crystal display panel 1 and the cell case 3 to the circuit board 5. 7 etc.

  Although not shown in detail, the liquid crystal display panel 1 includes liquid crystal molecules sealed between a front glass substrate 11 and a rear glass substrate 12, and a polarizing film is pasted on each glass substrate 11 and 12, as is well known. is there. When a signal (voltage) corresponding to an external measurement amount is applied to the electrode portions formed on the glass substrates 11 and 12, the operating state of the vehicle (for example, the speed and travel distance of the vehicle, or the remaining amount of fuel) The liquid crystal display section on which is displayed appears in black. The background portion other than the liquid crystal display portion is transmitted and illuminated by lighting of the light emitting diode 4.

  Although not shown in detail, the conductive rubber 6 has a laminated structure in which conductive layers and insulating layers are alternately laminated along the longitudinal direction, and is formed by being drawn from the electrode portion on the front glass substrate 11 of the liquid crystal display element 1. The circuit board 5 and the liquid crystal display element 1 are disposed between the electrode terminal 13 and the circuit terminal 51 formed around the circuit board 5, and are in close contact between the electrode terminal 13 and the circuit terminal 51. It is an energizing member having elasticity for achieving conduction.

  The diffusion plate 2 uniformly guides the light from the light emitting diode 4 to the back side of the liquid crystal display panel 1, and the outer shape is substantially the same as that of the liquid crystal display panel 1. Although not shown, the diffusion plate 2 has a white transmissive layer printed on the surface (surface on the liquid crystal display panel 1 side) of a sheet material made of, for example, a polycarbonate resin that is a colorless and transparent synthetic resin. In addition, light control printing (halftone printing or the like) is performed on the back surface (light emitting diode 4 side) so that the light irradiated on the diffusion plate 2 is almost uniform and emitted to the liquid crystal display panel 1 side. In addition, a protruding piece 21 protrudes from one edge in the longitudinal direction, and a positioning piece 22 that positions the cell case 3 protrudes from the other edge. Note that the diffusion plate 2 may be a synthetic resin sheet material having transparency, for example, milky white.

  The cell case 3 is made of, for example, white synthetic resin, and includes an upper side wall 311 located on the peripheral side of the diffusion plate 2 and the liquid crystal display panel 1, and a lower side wall 312 located on the lower side (circuit board 5 side) from the diffusion plate 2. Are provided corresponding to the light emitting diodes 4, the diffusion plate mounting surface 313 and the panel mounting surface 314 formed on the side wall 31 on which the peripheral edges of the diffusion plate 2 and the liquid crystal display panel 1 are respectively mounted. The bottom wall 32 having the formed opening hole 321 and the outer wall 33 provided in parallel to the outside of the side wall 31A along the side wall 31A corresponding to the electrode terminal 13 formed in the liquid crystal display panel 1 are provided. By providing the outer wall 33, the conductive rubber 6 is inserted (arranged) in a space S1 formed between the side wall 31A. The size of the void S1 is approximately equal to the thickness of the conductive rubber 6.

  In addition, a base 34 is provided on the outer side of the side wall lower portion 312 corresponding to the protruding piece 21 of the diffusion plate 2 (the outer surface side of the side wall lower portion 312) so as to protrude to the outer peripheral side of the side wall 31. The upper surface 341 of the base 34 is substantially the same height as the diffusion plate mounting surface 313. A groove hole 35 through which the protruding piece 21 is inserted is provided at 31 locations on the side wall connecting the diffusion plate mounting surface 313 and the upper surface 341 of the base portion 34. The groove 35 has a groove 35 (gap) larger than the plate thickness of the protruding piece 21 so that the protruding piece 21 can be inserted into the groove 35 even if the diffusing plate 2 or the cell case 3 has a dimensional variation. Is slightly larger. In the present embodiment, a space S <b> 2 that is the same as the thickness of the side wall upper part 311 is provided at the lower part 312 of the side wall below the groove 35 (circuit board 5 side).

  In addition, a protrusion 342 is provided on the upper surface 341 of the base 34. The protruding portion 342 has a wedge shape having an inclined surface 343 that faces the upper side (viewing side of the display device) and also faces the slot 35. By providing the wedge-shaped protrusion 342, the slot 35 is narrowed. That is, as shown in FIG. 4, the gap W <b> 1 between the inner surface portion P <b> 1 on the side wall upper portion 311 side formed by providing the groove 35 and the tip portion P <b> 2 of the protrusion 342 is the size (gap) of the groove 35. ) And is smaller than the thickness of the protruding piece 21 (diffusion plate 2) of the diffusion plate 2. However, the gap W2 on the side along the inclined surface 343 (where the gap is widest) is wider than the plate thickness of the protruding piece 21. The sizes (dimensions) of the gaps W1 and W2 are set so that the sizes (dimensions) of the gaps W1 and W2 can be maintained even if the diffusion plate 2 and the cell case 3 have dimensional variations. It is as.

  Further, a holding piece 36 that locks the upper surface of the edge of the diffusion plate 2 at 31 locations on the side wall of the cell case 3 corresponding to both ends of the edge opposite to the edge of the diffusion plate 2 provided with the protruding piece 21. Is provided. Further, the upper surface of the edge of the diffusion plate 2 is also associated with the side walls 31 and 31A of the cell case 3 corresponding to the edges on both sides orthogonal to the edge provided with the protruding piece 21 and close to the center of the diffusion plate 2. A holding piece 36 for stopping is provided.

  In addition, positioning pins 322 are formed at appropriate positions on the bottom wall 32. The positioning pin 322 is inserted into a positioning hole 52 provided in the circuit board 5 to position the cell case 3 and the circuit board 5.

  The presser frame 7 is formed by pressing a metal plate. A frame-shaped cover 71 that continuously covers the peripheral upper surface of the liquid crystal display panel 1 and the side wall 31 and the outer wall 33 of the cell case 3 from the cover 71. A frame-like side portion 72 extending toward the circuit board 5 along the plurality of leg portions 73 provided at appropriate locations on the side portion 72 and having a locking portion 731 on the lower end side. A synthetic rubber sheet 8 is disposed between the cover 71 and the peripheral upper surface of the liquid crystal display panel 1. The synthetic rubber sheet 8 is for buffering the cover 71 and the liquid crystal display panel 1 and is pasted on the cover 71 of the holding frame 7 in advance.

  Next, a method for holding the diffusion plate 2 in the cell case 3 will be described with reference to FIG. The protruding piece 21 provided on the diffusion plate 2 is inserted into the slot 35 while moving on the diffusion plate mounting surface 313 from the center side (left side in FIG. 5) of the cell case 3. Then, the tip of the protruding piece 21 comes into contact with the inclined surface 343 of the protrusion 342 provided on the upper surface 341 of the base 34 (see FIG. 5). If the projecting piece 21 is further inserted deeply into the slot 35 from this state, the tip of the projecting piece 21 moves while being elastically deformed upward along the inclined surface 343, and the state as shown in FIG. Become. That is, when the protruding piece 21 of the diffusing plate 2 placed on the diffusing plate placement surface 313 is inserted into the groove 35, the tip end side of the protruding piece 21 is a protruding portion with the inner surface portion P1 on the side wall upper portion 311 side as a fulcrum. It is pressed upward by 342. Thus, the diffusion plate 2 is held by the cell case 3 with the protruding piece 21 elastically deformed.

  In addition, the diffusion plate 2 is inserted between the suppression piece 36 and the diffusion plate mounting surface 313 while bending the diffusion plate 2 at the place where the suppression piece 36 is provided. As a result, the upper surface of the edge of the diffusion plate 2 is locked by the holding piece 36 and is held by the cell case 3 (see FIG. 6).

  The liquid crystal display device is assembled as follows. After the positioning pins 322 of the cell case 3 holding the diffusion plate 2 are inserted into the positioning holes 52 of the circuit board 5, the conductive rubber 6 is disposed in the space S <b> 1 formed in the cell case 3. Next, the liquid crystal display panel 1 is placed on the panel placement surface 314 of the cell case 3, and the pressing frame 7 is attached from above the liquid crystal display panel 1. At that time, the locking portion 731 and the leg portion 73 provided on the holding frame 7 are moved along the side wall 31 and the outer wall 33 of the cell case 3, and the leg portion 73 having the locking portion 731 is provided on the circuit board 5. The hole 53 is inserted. Then, each locking portion 731 is bent on the back side of the circuit board 5. By doing so, the liquid crystal display panel 1 is held by the cell case 3 and is assembled to the circuit board 5. Note that the diffusion plate 2 may be held by the cell case 3 after the cell case 3 is arranged on the circuit board 5. In addition, the liquid crystal display panel 1 may be press-fitted and fixed on the side wall 31 of the cell case 3 or may be a so-called hook stop by providing an elastic locking piece on the side wall 31.

  In this way, the side wall 31 of the cell case 3 is provided with the slot 35 through which the protruding piece 21 provided on the diffusion plate 2 is inserted, and the base 34 is provided outside the side wall 31 corresponding to the slot 35. By providing the protrusion 342 protruding in the direction of narrowing the groove 35 on the upper surface 341 of 34, the protruding piece 21 inserted through the groove 35 by the protrusion 342 is held in the cell case 3 in an elastically deformed state. . Therefore, even if dimensional variation occurs in the cell case 3 or the diffusion plate 2, the diffusion plate 2 is securely held by the cell case 3, and even if vibration is applied to the liquid crystal display device, generation of abnormal noise and abrasion powder is suppressed. Is possible.

  Further, by providing the protrusion 342 at a position corresponding to the lower side of the slot 35, the projecting piece 21 which is the end of the diffusion plate 2 is deformed upward, so that the substantially center of the diffusion plate 2 is It becomes easy to bend to the lower side (circuit board 5 side). Therefore, the diffusion plate 2 and the liquid crystal display panel 1 are brought into contact with each other due to vibration, and abnormal noise is generated, or the transmission layer printed on the diffusion plate 2 is transferred to the liquid crystal display panel 1 due to the contact and adversely affects display and illumination. There is no fear that it will affect.

  Further, since the inclined surface 343 facing the groove hole 35 is provided on the tip side of the protrusion 342, the protruding piece 21 extends along the inclined surface 343 when the protruding piece 21 of the diffusion plate 2 is inserted into the groove hole 35. Therefore, it is moved while being elastically deformed upward, so that the insertion workability is good.

  Further, by providing the cell case 3 with the holding piece 36 that locks the upper surface of the edge of the diffusion plate 2, the diffusion plate 2 is more securely held by the cell case 3, and abnormal noise and abrasion powder are generated due to vibration. Can be suppressed. In particular, if the restraining piece 36 is provided at an edge corresponding to the vicinity of the center of the diffusion plate 2 that easily shakes due to vibration, it is more advantageous to suppress the generation of abnormal noise and rubbing powder.

  In the present embodiment, the protruding piece 21 is provided only on one edge of the diffusion plate 2 in the longitudinal direction. However, both protruding pieces 21 are held in the cell case 3 by being provided on the other edge. You may make it let it. Further, the holding piece 36 may be set as appropriate.

  In the present embodiment, the base 34 and the protrusion 342 provided on the upper surface 341 of the base 34 have been described separately. However, both the base 34 and the protrusion 342 may be combined to form a protrusion.

  Further, although the conductive rubber 6 is used as a current-carrying member between the liquid crystal display panel 1 and the circuit board 5, an FPC or a metal pin may be used. Further, although the metal holding frame 7 is used to fix the liquid crystal display panel 1 and the cell case 3 to the circuit board 5, a holding frame made of synthetic resin may be used. In that case, the holding frame may be screwed to the circuit board 5 or the holding frame may be hooked to the circuit board 5 using an elastic locking piece.

  In addition, the liquid crystal display device of the present invention can be applied even when the liquid crystal display device is incorporated in a vehicle meter device equipped with a speedometer, a tachometer, etc. In this case, the cell case is a meter constituting the meter device. It may be integral with the case.

The disassembled perspective view of the liquid crystal display device which shows embodiment of this invention. Sectional drawing of the liquid crystal display device which shows the AA direction in FIG. Sectional drawing of the liquid crystal display device which shows the BB direction in FIG. The principal part sectional drawing of the cell case location where a diffusion plate is hold | maintained. The principal part sectional drawing of the cell case location which shows the state by which a diffuser plate is hold | maintained. The principal part sectional drawing which shows the state by which the edge part upper surface of the diffusion plate was latched.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display panel 2 Diffusion plate 21 Projection piece 3 Cell case 31, 31A Side wall 342 Projection part 343 Inclination surface 35 Groove hole 36 Holding piece 4 Light emitting diode (light source)
5 Circuit board

Claims (4)

  A liquid crystal display panel; a sheet-shaped diffusion plate disposed behind the liquid crystal display panel and having a protruding piece at an edge; the liquid crystal display panel; a cell case holding the diffusion plate; the liquid crystal display panel; A light source for illuminating the diffuser plate from behind, and a groove hole through which the protruding piece is inserted is provided on the side wall of the cell case, and the groove hole is protruded in a direction of narrowing the outside of the side wall corresponding to the groove hole. A liquid crystal display device provided with a protruding portion.   The liquid crystal display device according to claim 1, wherein the protrusion is provided at a position corresponding to a lower side of the groove.   The liquid crystal display device according to claim 1, wherein an inclined surface facing the groove hole side is provided on a tip end side of the protrusion.   The liquid crystal display device according to any one of claims 1 to 3, wherein a holding piece for locking an upper surface of an edge of the diffusion plate is provided in the cell case.

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