JP4154906B2 - LCD module - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal display module having an edge light type backlight.
[0002]
[Prior art]
Some liquid crystal display modules have an edge light type backlight disposed on the back side of a liquid crystal display panel. FIG. 3 is a plan view of a part of an example of such a conventional liquid crystal display module, and FIG. 4 is a cross-sectional view taken along line BB in FIG. However, in FIG. 3, the cover case 2 shown in FIG. 4 is not shown for convenience of explanation. In the following description, the display surface side of the liquid crystal display module is referred to as the front side, and the back side is referred to as the back side.
[0003]
The liquid crystal display module includes a resin storage case 1 and a sheet metal cover case 2 disposed on the front side thereof. Among these, the storage case 1 has a substantially rectangular planar shape, and the engagement protrusions 3 are provided at a plurality of predetermined positions on the side surface. The cover case 2 has a rectangular display window 4, and engagement holes 5 are provided at a plurality of predetermined locations on the side wall. The cover case 2 is attached to the front side of the storage case 1 with the engagement hole 5 engaged with the engagement protrusion 3 of the storage case 1.
[0004]
The storage case 1 is provided with a panel storage portion 6 that is formed of a rectangular recess opened on the front side and that stores a panel member such as a liquid crystal display panel or a light guide plate. In this case, the surface of the bottom portion 6a of the panel storage portion 6 is an inclined surface such that the depth of the storage portion 6 gradually increases toward the cold cathode tube storage portion 7 described below.
[0005]
In FIG. 3, a cold-cathode tube storage portion 7 formed of a concave portion opened on the back side of the belt-like shape is provided at one long side edge of the storage case 1. The cold cathode tube storage unit 7 and the panel storage unit 6 are partitioned by a partition wall 9 in which an opening 8 is formed. The partition wall 9 is erected perpendicularly to the bottom side 1 a of the storage case 1, and opposes the lower surface of the partition wall 9, that is, the end surface serving as a light incident surface of a light guide plate 11 described later stored in the panel storage unit 6. The opening 8 is formed by cutting a portion to be cut into a rectangular shape.
[0006]
An edge light type backlight 11 is housed in the panel housing 6 and the cold cathode tube housing 7. That is, the backlight 11 includes a light guide plate 12 housed on the bottom 6 a side in the panel housing portion 6, a cold cathode tube 13 housed in the back of the cold cathode tube housing portion 7, and the like.
[0007]
Of these, the light guide plate 12 has one end surface on the opening 8 side as the incident surface 14, the front surface as the emission surface 15, and the thickness of the light guide plate 2 gradually increases from the incident surface 14 side toward the opposite side. The inclined surface 16 is thinned. A prism sheet 17 is attached to the emission surface 15 of the light guide plate 12, and a reflection sheet 18 is attached to the inclined surface 16. The light guide plate 12 and the like are stored on the bottom 6a side in the panel storage unit 6 in a state where the reflection sheet 18 is disposed along the surface of the bottom 6a of the panel storage unit 6.
[0008]
The cold-cathode tube 13 has cylindrical rubber holders 19 inserted at both ends thereof, and the rubber holders 19 are forcibly pushed into the cold-cathode tube storage portion 7 while elastically deforming the rubber holders 19. And is stored in the inner part of the cold cathode tube storage unit 7 while being held on the inner wall surface. In this state, the cold cathode tube 13 is disposed at a position facing the incident surface 14 of the light guide plate 12 with the opening 8 interposed therebetween. A reflector 20 is provided along a part of the outer peripheral surface of the cold cathode tube 13.
[0009]
A liquid crystal display panel 21 is housed on the front side of the prism sheet 17 of the backlight 11 in the panel housing portion 6. In the liquid crystal display panel 21, two glass substrates 22 and 23 are bonded to each other through a substantially rectangular frame-shaped sealing material (not shown), and a liquid crystal (not shown) is sealed between them. Further, polarizing plates 24 and 25 are attached to the back surface of the glass substrate 23, respectively. The liquid crystal display panel 21 is housed on the surface side of the prism sheet 17 of the backlight 11 in the panel housing portion 6 with the one end face 21 a positioned in contact with the inner surface of the partition wall 9.
[0010]
Note that a plurality of locking projections 26 for locking the circuit board are provided at predetermined positions on the back surface of the bottom portion 6a of the panel storage portion 6. The end portions of the circuit board 27 are locked to the locking protrusions 26. As shown in FIG. 3, attachment plates 29 having attachment holes 28 are respectively provided at two predetermined positions on one end surface of the storage case 1.
[0011]
In the liquid crystal display module configured as described above, the light emitted from the cold cathode tube 13 and the light reflected by the reflector 20 are incident on the incident surface 14 of the light guide plate 12 through the opening 8.
[0012]
The light incident on the incident surface 14 of the light guide plate 12 travels (guides) from the incident surface 14 side toward the opposite side in the light guide plate 12, is reflected by the reflection sheet 18, and is emitted from the light guide plate 12. The light is emitted from the surface 15.
[0013]
The light emitted from the emission surface 15 of the light guide plate 12 is collected by the prism sheet 17. The condensed light is incident on the back surface of the liquid crystal display panel 21, and image light corresponding to display driving of the liquid crystal display panel 21 is emitted from the front surface of the liquid crystal display panel 21.
[0014]
[Problems to be solved by the invention]
By the way, in the conventional liquid crystal display module, since the cold cathode tube 13 generates heat when it is lit, this heat is supplied to the liquid crystal display panel 21 via the storage case 1, the cover case 2, the light guide plate 12 and the like in the vicinity of the cold cathode tube 13. Conducted unevenly. As a result, there is a problem that heat distribution unevenness occurs in the liquid crystal of the liquid crystal display panel 21 and display unevenness occurs due to the heat distribution unevenness.
The subject of this invention is providing the liquid crystal display module which can prevent the display nonuniformity by the heat distribution nonuniformity resulting from the heat_generation | fever of a light source.
[0015]
[Means for Solving the Problems]
The present invention, as described in claim 1, disposed to face the rear side opposite to the liquid crystal display panel formed by sealing a liquid crystal between a pair of substrates, the display surface side of the liquid crystal display panel, an end face A light guide plate that emits light incident from the light source toward the back surface of the liquid crystal display panel, a line light source that emits light linearly and makes this light incident on a predetermined end surface of the light guide plate, and a rectangular recess becomes, the liquid crystal display panel and the light guide plate is a light guide plate liquid crystal display panel housing portion by stacking are received in the recess on top of is positioned on the rear side bottom portion forming a bottom of the recess of the panel And a resin storage case provided in parallel with the panel storage part via a partition wall and provided with a light source storage part for storing the linear light source , and attached to the display surface side of the storage case, the liquid crystal Table for observing the display surface of the display panel In the liquid crystal display module and a cover case having a window, it is disposed throughout the bottom from one end in the vicinity of the line light source along the inside of the bottom surface of the recess of the panel housing portion, emitted from the line light source A heat transfer plate that uniformly conducts part of the generated heat to the back surface of the light guide plate, and one end portion in the vicinity of the line light source is brought into contact with one end portion of the heat transfer plate to form the panel housing portion. And a heat radiating plate disposed along the bottom rear surface outside the recess and dissipating another part of the heat generated from the line light source into the atmosphere.
And according to this invention, by the heat sink provided on the bottom back surface of the storage case, a part of the heat generated by the line light source is quickly radiated, and by the heat transfer plate provided on the bottom surface of the storage case, Of the heat generated by the line light source, heat conducted to the liquid crystal display panel through the light guide plate is made uniform throughout the light guide plate, thereby preventing display unevenness due to heat distribution unevenness of the liquid crystal display panel caused by the heat generation of the line light source. be able to.
In this case, as described in claim 2, protrusions for positioning the liquid crystal display panel are formed at both side end portions of the partition wall so as to contact the side portion of one end face of the liquid crystal display panel, and the linear light source It is preferable that a space for suppressing heat conduction from to the liquid crystal display panel is provided.
In addition, as described in claim 3, heat conduction from the linear light source to the liquid crystal display panel through the cover case is suppressed in a portion of the cover case that covers the light source storage portion. It is preferable that a notch is provided.
Further, as described in claim 4, the line light source, it is preferable to arrange shifted by a predetermined amount to the rear side of the liquid crystal display panel from the position directly facing to the end surface of the light guide plate.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a plan view of a liquid crystal display module as an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line AA in FIG. However, in FIG. 1, the cover case 32 shown in FIG. 2 is not shown.
[0017]
The liquid crystal display module includes a resin storage case 31 and a sheet metal cover case 32 disposed on the surface side thereof. Among these, the storage case 31 has a substantially rectangular planar shape, and engagement projections 33 are provided at a plurality of predetermined positions on the side surface. The cover case 32 has a rectangular display window 34, and engagement holes 35 are provided at a plurality of predetermined locations on the side wall. The cover case 32 is attached to the front side of the storage case 31 with the engagement hole 35 engaged with the engagement protrusion 33 of the storage case 31.
[0018]
The storage case 31 is provided with a panel storage portion 36 formed of a rectangular recess that opens to the front side over a region excluding the one edge portion. Panel members such as a liquid crystal display panel and a light guide plate are stored in the panel storage unit 36. In this case, the surface of the bottom portion 36a of the panel storage portion 36 is inclined so that the depth of the storage portion 36 gradually increases toward the cold cathode tube storage portion 37 described below.
[0019]
A cold cathode tube storage portion 37 is provided at the edge of one long side of the storage case 31. The cold cathode tube storage portion 37 is a recess opened on the back side extending along the edge. Positioning struts 38 are erected on the front wall surfaces at both ends in the cold cathode tube storage unit 37 so as to face the back side. The positioning column 38 has its tip end face abutted against the end of the cold cathode tube stored therein, and determines the holding position of the cold cathode tube.
[0020]
The cold cathode tube storage part 37 and the panel storage part 36 are partitioned by a partition wall 40 in which an opening 39 is formed. The partition wall 40 is erected vertically with respect to the bottom 31a of the storage case 31, and has a lower portion of the partition wall 31, that is, an end surface 54 serving as a light incident surface of a light guide plate 51 described later stored in the panel storage portion 36. Opposing portions are cut out in a rectangular shape to form an opening 39 .
[0021]
Both end portions of the partition wall 40 protrude from the surface 37 a of the cold cathode tube storage portion 37 by a predetermined length. Only the both side portions of one end surface of the liquid crystal display panel 61, which will be described later, are brought into contact with these protruding portions 40a, 40a, and the end surface positions thereof are determined. Thus, by suppressing the contact area between the partition wall 40 heated by the cold cathode tube and the liquid crystal display panel 61 to a necessary minimum area, occurrence of uneven heat distribution of the liquid crystal display panel 61 is suppressed. be able to. Note that the liquid crystal display panel end face positioning protrusions 40 a are not limited to the above-described configuration, and a plurality of protrusions 40 a may be provided at the center of the partition wall 40. That is, a cutout portion is provided in a portion of the partition wall 40 that faces the end surface of the liquid crystal display panel 61 so that the contact area between the end surface of the liquid crystal display panel 61 and the partition wall 40 is the minimum necessary for positioning. .
[0022]
In FIG. 2, one or a plurality of slit-shaped notches 43 are provided in a portion of the cover case 32 that covers the cold cathode tube storage portion 37.
[0023]
A heat transfer plate 44 made of aluminum or the like having high thermal conductivity is disposed on almost the entire surface of the bottom portion 36a of the panel storage portion 36. One end portion (right end portion in FIG. 2) 44a on the light source side of the heat transfer plate 44 extends to the vicinity of a cold cathode tube 53 described later through the opening 39, and is curved along the peripheral surface thereof.
[0024]
Further, a heat radiating plate 45 made of aluminum or the like having high thermal conductivity is disposed in almost half of the light source side of the back surface of the bottom portion 36a in the panel housing portion 36 (a region where a circuit board 67 described later is not disposed). Similarly to the above-described heat transfer plate 44, the heat radiating plate 45 has a light source side one end (the right end in FIG. 2) 45a that extends to the vicinity of the cold cathode tube storage portion 37 and is appropriately curved. 44 is in close contact with the back surface of one end 44a.
[0025]
An edge light type backlight 51 is housed in the panel housing portion 36 and the cold cathode tube housing portion 37. That is, the backlight 51 includes a light guide plate 52 housed on the bottom 36a side in the panel housing portion 36, a cold cathode tube (line light source) 53 housed on the inlet side in the cold cathode tube housing portion 37, and the like.
[0026]
Among these, the light guide plate 52 has one end surface on the opening 39 side as an incident surface 54, a surface extending at right angles to one end surface as an output surface 55, and its rear surface from the incident surface 54 side to the opposite side. The light guide plate 52 has an inclined surface 56 that gradually decreases in thickness as it goes. A prism sheet 57 is attached to the emission surface 55 of the light guide plate 52, and a reflection sheet 58 is attached to the inclined surface 56. The reflection sheet 58 is for preventing light leakage from the inclined surface 56 of the light guide plate 52 and improving light use efficiency. The light guide plate 52 and the like are housed on the bottom 36 a side in the panel housing portion 36 in a state where the reflection sheet 58 is disposed along the surface of the heat transfer plate 44.
[0027]
The cold-cathode tube 53 is inserted with cylindrical rubber holders 59 at both ends thereof, and the rubber holders 59 are forcibly deformed while being elastically deformed until they come into contact with the front end surface of the positioning column 38 in the cold-cathode tube storage portion 37. The cold-cathode tube storage portion 37 is held between both end portions of the cold cathode tube storage portion 7 facing each other through the rubber holder 17 and in contact with the front end surface of the positioning column 38. It is stored in the entrance part. That is, the cold-cathode tube 53 is disposed not at the front position where the entrance surface 54 of the light guide plate 52 is aligned with the center of the opening 39 and facing the center but at a position shifted by a predetermined amount from the front position to the back side. . In this way, by shifting the cold cathode tube 53 from the front position to the incident surface 54 of the light guide plate 51 to the back side, the light use efficiency is improved and the heat distribution due to the heat generation of the cold cathode tube 53 with respect to the liquid crystal display panel 61 described later. Generation of unevenness can be suppressed.
[0028]
A reflector 60 is attached to the cold cathode tube 53. The reflector 60 is for efficiently allowing the light emitted from the cold cathode tube 53 to enter the incident surface 54 of the light guide plate 52, and is provided so as to cover a part of the outer peripheral surface of the cold cathode tube 53. Is attached to the back surface of the reflection sheet 58 on the incident surface 54 side, and the other end is along a predetermined wall surface in the cold cathode tube storage unit 37. The one end side of the reflector 60 is in close contact with the surface of the one end 44 a of the heat transfer plate 44. That is, one end of the reflector 60 is sandwiched between the front and back surfaces of the reflector 60 in close contact with the reflection sheet 58 and the heat transfer plate 44.
[0029]
A liquid crystal display panel 61 is housed on the front side of the prism sheet 57 of the backlight 51 in the panel housing portion 36. In the liquid crystal display panel 61, two glass substrates 62 and 63 are bonded together via a substantially rectangular frame-shaped sealing material (not shown), and a liquid crystal (not shown) is sealed between them, and the surface of the glass substrate 62 Further, polarizing plates 64 and 65 are attached to the back surface of the glass substrate 63, respectively. Then, the liquid crystal display panel 61 is positioned in the panel storage portion 36 in a state where the both end portions of the one end surface 61a are positioned in contact with the inner surfaces of the both end protrusion portions 40a of the partition wall 40 described above. 51 is housed on the front side.
[0030]
A plurality of locking projections 66 for locking the circuit board are provided at a plurality of predetermined positions on the back surface of the bottom portion 36 a of the panel storage portion 36. The end portions of the circuit board 67 are locked to the locking protrusions 66. As shown in FIG. 1, attachment plates 69 each having attachment holes 68 are provided at two predetermined positions on one end surface of the storage case 31.
[0031]
In the liquid crystal display module configured as described above, the light emitted from the cold cathode tube 53 and the light reflected by the reflector 60 are incident on the incident surface 54 of the light guide plate 52 through the opening 39.
[0032]
The light incident on the incident surface 54 of the light guide plate 52 travels (guides) from the incident surface 54 side toward the opposite side in the light guide plate 52, is reflected by the reflection sheet 58, and is emitted from the light guide plate 52. The light is emitted from the surface 55.
[0033]
Light emitted from the emission surface 55 of the light guide plate 52 is collected by the prism sheet 57. The condensed light is incident on the back surface of the liquid crystal display panel 61, and image light corresponding to display driving of the liquid crystal display panel 61 is emitted from the front surface of the liquid crystal display panel 61.
[0034]
In this liquid crystal display module, a part of the heat generated from the cold cathode tube 53 is conducted to the one end portion 45 a of the heat radiating plate 45 through the reflector 60 and the one end portion 44 a of the heat transfer plate 44, and the heat radiating plate 45. Since heat is quickly radiated from the whole, it is possible to suppress the heat generated in the cold cathode tube 53 from being transmitted to the liquid crystal display panel 61. Further, heat conducted from the one end portion 44a of the reflector 60 or the heat transfer plate 44 to the light guide plate 52 side without being conducted to the heat radiating plate 45 is quickly transferred to the entire back surface of the light guide plate 52 by the heat transfer plate 44. As a result, the entire light guide plate 52 is heated substantially uniformly, and thus the occurrence of uneven heat distribution in the liquid crystal display panel is suppressed.
[0035]
Further, since only the both end portions of the one end surface 61a of the liquid crystal display panel 61 are in contact with the protruding portion 40a of the partition wall 40, the heat generated from the cold cathode tube 53 is liquid crystal via the storage case 31 in the vicinity thereof. Conduction to the one end face 61a of the display panel 61 can be suppressed.
[0036]
Further, in FIG. 2, one or a plurality of slit-like cutout portions 43 are provided in a portion of the cover case 32 that covers the cold cathode tube storage portion 37. The heat conducted to the one end face 61a of the liquid crystal display panel 61 through the nearby cover case 32 can be suppressed to some extent. Further, the notch 43 contributes to dissipating heat staying in the space surrounded by the cold cathode tube storage part 37 and the cover case 32.
[0037]
Further, since the cold cathode tube 53 is disposed not at the front position facing the incident surface 14 of the light guide plate 52 across the opening 39 but at a predetermined amount from the front position to the back side, the cold cathode tube 53 and A relatively large space is formed between the incident surface 54 of the light guide plate 52, and this space functions as a kind of heat insulating layer, and the heat generated by the cold cathode tube 53 is transmitted through the light incident side end of the backlight 51. Propagation to the one end face 61 a of the liquid crystal display panel 61 can be suppressed.
[0038]
As a result of the above, promotion of heat radiation by the heat radiating plate 45, suppression of heat conduction by the panel housing structure including the protruding portion 40a of the partition wall 40 and the cutout portion 43 provided in the cover case 32, and conduction with the cold cathode tube 53 are achieved. Due to the heat insulation effect of the air layer secured between the light incident surface 54 of the light plate 52 and the heat conduction from the cold cathode tube 53 to the liquid crystal of the liquid crystal display panel 61, the heat conduction by the heat transfer plate 44 is suppressed. Due to the homogenization, the heat conducted to the liquid crystal display panel 61 can be conducted to the entire liquid crystal display panel 61 as uniformly as possible. Accordingly, display unevenness due to heat distribution unevenness caused by heat generation of the cold cathode tube 53 can be remarkably prevented.
[0039]
【The invention's effect】
As described above, according to the present invention, the heat radiation plate provided on the bottom surface of the storage case quickly radiates a part of the heat generated by the line light source, and the transmission provided on the bottom surface of the storage case. Of the heat generated by the line light source by the heat plate, the heat conducted to the liquid crystal display panel through the light guide plate is made uniform throughout the light guide plate, thereby displaying the heat distribution unevenness of the liquid crystal display panel caused by the heat generated by the line light source. The occurrence of unevenness can be remarkably prevented.
[Brief description of the drawings]
FIG. 1 is a plan view of a part of a liquid crystal display module as one embodiment of the present invention.
FIG. 2 is a cross-sectional view corresponding to a portion along line AA in FIG.
FIG. 3 is a plan view of a part of an example of a conventional liquid crystal display module.
4 is a cross-sectional view corresponding to a portion along the line BB in FIG. 3;
[Explanation of symbols]
31 Storage Case 32 Cover Case 34 Display Window 36 Panel Storage Unit 37 Cold Cathode Tube Storage Unit 40 Partition Wall 40a Projection 43 Notch 44 Heat Transfer Plate 45 Heat Dissipation Plate 51 Backlight 52 Light Guide Plate 53 Cold Cathode Tube 61 Liquid Crystal Display Panel

Claims (4)

A liquid crystal display panel in which liquid crystal is sealed between a pair of substrates and a back surface side opposite to the display surface side of the liquid crystal display panel are arranged opposite to each other , and light incident from the end surface is directed to the back surface of the liquid crystal display panel a light guide plate for emitting Te, light is emitted in a linear, a linear light source to be incident to the light to a predetermined end surface of the light guide plate, made of rectangular recesses, the liquid crystal display panel and the light guide plate is the conductive panel accommodating unit to be housed in the recess are stacked on the bottom by the optical plate is positioned on the rear side of the liquid crystal display panel forming the bottom of the recess, and parallel through the partition wall to the panel housing portion A resin storage case provided with a light source storage unit for storing the linear light source , and a display window attached to the display surface side of the storage case for observing the display surface of the liquid crystal display panel A liquid having a cover case In the display module is disposed across from one end in the vicinity of the bottom of the inside of the bottom the line light source along the surface of the recess of the panel housing portion, said guide part of the heat emitted from the line light source A heat transfer plate that conducts uniformly to the back surface of the light plate, and one end portion in the vicinity of the line light source is in contact with one end portion of the heat transfer plate, and along the bottom back surface outside the recess that forms the panel housing portion And a heat radiating plate that dissipates another part of the heat generated from the line light source into the atmosphere. In the invention according to claim 1, protrusions for positioning the liquid crystal display panel are formed at both side end portions of the partition wall so as to abut on a side portion of one end face of the liquid crystal display panel, and the liquid crystal from the line light source A liquid crystal display module characterized in that a space for suppressing heat conduction to the display panel is provided. 2. The rectangular cutout for suppressing heat conduction from the linear light source to the liquid crystal display panel in the display surface side portion of the cover case that covers the light source storage portion of the cover case. A liquid crystal display module comprising a portion. Liquid crystal display module in the invention described in claim 1, said line light source, characterized by being staggered a predetermined amount from the position directly facing to the end surface of the light guide plate to the back side of the liquid crystal display panel.

Images