JP4957144B2 - Flat image display module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat type image display module with a speaker which is small-sized and thin, despite its providing a speaker device and improves the reliability of accurately and clearly listen to sounds on a front side where a display is observed, without reducing the sound quality. <P>SOLUTION: A sound source unit 3 is disposed inside a bottom plate recess 411 inside an exterior case 4 formed from an insulated resin material, and a back light unit 2 and a liquid crystal display unit 1 are sequentially fitted in and housed thereon. A sound source element, which a pair of thin film electrodes 32a, 32b are conduction-bonded to a piezoelectric ceramic plate 31 and a flexible wiring board 34, which inputs a sound source signal to the sound source element are conduction-connected to the sound source unit 3 by a solder 35 and both front and rear surfaces of the piezoelectric ceramic plate 31 are held in between a lacked torus elastic pressing spacer 33, comprising an opening 331 and an elastic holding spacer 42 being planted on a bottom plate 41, respectively. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a flat image display module including a speaker device.

  2. Description of the Related Art In recent years, flat image display panels (hereinafter referred to as FPD (Flat Panel Display)) suitable for miniaturization and thinning such as liquid crystal display panels and organic EL displays have been used as displays for mobile devices such as mobile phones.

  On the other hand, mobile phones are evolving from simple telephones to multifunction devices having functions such as TVs and PDAs (Personal Data Assistants), and as a display used in such mobile devices, not only displays images. A speaker device that emits sound is also required.

As an example of an FPD of a mobile device provided with a speaker device, a vehicle-mounted liquid crystal display panel as shown in Patent Document 1 is known.
Japanese Patent Laid-Open No. 62-231847

  In the above-described in-vehicle liquid crystal display panel, a video display and a speaker device are arranged in parallel on the front surface of the device. When the speaker device is arranged in parallel with the video display on the front side of the device in this way, the area of the entire device increases accordingly, and it is used as a display for a mobile device such as a mobile phone, where miniaturization and thinning are the most important issues. I can't.

  In order to reduce the area, the speaker device may be arranged on the back side of the video display, but the thickness is increased instead. In addition, when the speaker device is arranged on the back side, an exposed conductive part such as a solder joint part between the electrode of the sound source element and the sound source signal input wiring contacts the frame or case formed of the conductive member. However, the sound source signal leaks through these conductive members, or the sound wave generated is not sufficiently propagated to the front side, so that the sound quality is deteriorated, and the sound is accurately and clearly displayed on the front side for observing the display. There is a problem that it cannot be heard.

  An object of the present invention is to provide a speaker-equipped flat panel which is small and thin despite having a speaker device, and which can be heard accurately and clearly without deteriorating the sound quality on the front side where the display is observed. A type image display module is provided.

The flat image display module of the present invention has a sound source element that emits a sound wave by a piezoelectric ceramic plate conductively connected to one end of a predetermined electrode, a bottom plate portion, and the sound source element between the display panel and the bottom plate portion. And a case for housing the display panel and the sound source element, and a flexible wiring board joined to the other end of the electrode by solder, and the solder is the bottom plate of the flexible wiring board It is provided on the surface facing the portion so as to protrude toward the bottom plate portion, and the bottom plate portion is characterized in that a region facing the solder is formed of an insulating resin material. .

According to the present invention, a speaker-equipped flat panel that is small and thin despite having a speaker device, and that can be heard accurately and clearly without deteriorating sound quality on the front side for observing the display. A type image display module can be provided.

(First embodiment)
FIG. 1 is a perspective view showing a liquid crystal display module as a first embodiment of the present invention, FIG. 2 is a sectional view taken along line II-II, and FIG. 3 is an exploded perspective view thereof.

  As shown in FIG. 3, the liquid crystal display module of the present embodiment is generally composed of a liquid crystal display unit 1, a backlight unit 2, a sound source unit 3, and an exterior case 4.

  The liquid crystal display unit 1 includes a liquid crystal display panel 12 housed in a panel case 11, and the liquid crystal display panel 12 forms a pair of rectangles with electrodes (not shown) formed thereon as shown in FIG. The glass substrates 121 and 122 are bonded to each other with the electrode forming surfaces facing each other with a frame-shaped sealing material (not shown) while maintaining a predetermined gap, and a liquid crystal is sandwiched between the glass substrates 121 and 122 surrounded by the frame-shaped sealing material. (Not shown) is enclosed. The panel case 11 is provided with a window 111 for observing the display. A flexible wiring board 13 (see FIG. 1) for supplying a control signal voltage for driving liquid crystal from an external drive control circuit board (not shown) is conductively joined to the liquid crystal display panel 12.

  On the back side opposite to the display side of the display of the liquid crystal display unit 1, a backlight unit 2 is installed. As shown in FIG. 3, the backlight unit 2 includes a light guide plate 21 formed of a substantially transparent rectangular plate, and a point light source element disposed opposite to one end surface (light incident end surface) of the light guide plate 21. An LED (Light-Emitting Diode) 22, a circuit board 23 on which a power supply wiring circuit for the LED 22 is formed, and an optical sheet laminate 24 laminated on the light emitting surface of the light guide plate 21 (front surface facing the liquid crystal display panel 12). The light reflecting sheet 25 is disposed on the rear surface of the light guide plate 21. In the present embodiment, three LEDs 22 are disposed to be evenly opposed to the light incident end face of the light guide plate 21, and these three LEDs 22 are directly mounted on the circuit board 23. In addition, as shown in FIG. 2, the optical sheet laminate 24 includes two prism sheets 241 and 242 that align the light emission direction and a light diffusion sheet 243 that are sequentially stacked on the light emission surface of the light guide plate 21. It becomes.

  A sound source unit 3 is installed on the back side of the backlight unit 2. The sound source unit 3 includes a disk-shaped piezoelectric ceramic plate 31, a pair of strip-shaped thin film electrodes 32 a and 32 b that are conductively attached to both surfaces thereof, and an elastic material interposed between the piezoelectric ceramic plate 31 and the backlight unit 2. It consists of a pressing spacer 33 made of a material and a flexible wiring board 34 for inputting a sound source signal on which wiring for applying a sound source signal voltage to the piezoelectric ceramic plate 31 via thin film electrodes 32a and 32b is formed.

  Here, as shown in FIG. 4, the pressing spacer 33 is formed in a partially annular shape in which an opening 331 is provided by cutting out a part of an annular shape whose outer diameter is slightly larger than the outer diameter of the piezoelectric ceramic plate 31. The opening 331 is positioned in the direction in which the sound wave oscillated from the front surface of the piezoelectric ceramic plate 31 (the side facing the backlight unit 2 is the front side) should be propagated, and is attached to the peripheral portion of the piezoelectric ceramic plate 31. It is worn. In other words, the opening 331 of the pressing spacer 33 is surrounded and formed between the piezoelectric ceramic plate 31 and the back surface of the backlight unit 2 (specifically, the back surface of the light reflecting sheet 25) by the notched annular pressing spacer 33. The space is communicated with a sound guide path to be described later. The pressing spacer 33 of this embodiment is formed using foamed PET (polyethylene terephthalate), which is an elastic material rich in stretchability.

  The sound source signal input flexible wiring board 34 has an insulating resin film such as a polyimide film as a base film 341, and a pair of wirings 342a and 342b are formed on one surface of the base film 341 by patterning a copper foil by photolithography. Yes. Output-side connection terminals 343a and 343b and input-side connection terminals 344a and 344b are formed at both ends of each wiring 342a and 342b, respectively. The output-side connection terminals 343a and 343b of the pair of wires 342a and 342b are soldered to the other end portions of the pair of thin film electrodes 32a and 32b whose one end portions are conductively bonded to both surfaces of the piezoelectric ceramic plate 31, respectively. Be joined. The sound source signal input flexible wiring board 34 is disposed on the back side of the base film 341 in such a manner that the back surface opposite to the wiring forming surface faces the backlight unit 2.

  The liquid crystal display unit 1, the backlight unit 2, and the sound source unit 3 described above are housed in an exterior case 4. The outer case 4 of the present embodiment is generally formed in an open top rectangular box shape having a planar outer shape that can fit and house the liquid crystal display unit 1 and the backlight unit 2 using an insulating resin material. A concave portion 411 extending over the entire length in the longitudinal direction is formed in the central portion of the bottom plate 41 of the exterior case 4. The sound source unit 3 is mounted in the recess 411.

  Therefore, a holding spacer 42 is provided at one end of the recess 411 for holding the sound source element 3 with the pressing spacer 33 described above. The holding spacer 42 is pre-molded into a shape shown in FIG. 4 using a resin material having a smaller elastic coefficient than the insulating resin material of the outer case 4, and this molded product is insert-molded when the outer case 4 is molded. The outer case 4 in which the holding spacers 42 are implanted at predetermined positions is formed in a lump.

  As shown in FIG. 4, the holding spacer 42 includes a cylindrical portion 421 having an outer diameter substantially equal to the outer diameter of the pressing spacer 33 and a flange portion 422 having a larger diameter than the cylindrical portion 421. A holding space 4211 in which the ceramic plate 31 is loaded and a closed vibration space 4212 having a smaller inner diameter and allowing the piezoelectric ceramic plate 31 to vibrate are formed. On the side wall for forming the holding space 4211, a notch 4213 for drawing out the thin film electrodes 32a and 32b is formed. The flange portion 422 is embedded in the case bottom plate 41.

  In the present embodiment, a liquid crystal polymer is used as the insulating resin material of the outer case 4, and an elastomer-modified PA (resin material having a high affinity with the liquid crystal polymer and having an elastic coefficient about 1/10 smaller than that is used as the resin material of the holding spacer 42. Polyamide (Poly Amide) 6 is used. In addition, as a combination of resin materials for the outer case 4 and the holding spacer 42 that is insert-molded thereto, for example, other than the above, the holding spacer material is TPEE (Thermoplastic-Polyester-Elastomer) with respect to the polycarbonate of the outer case material. Combinations of other materials are also possible, such as combinations.

  Thus, as shown in FIG. 2, the piezoelectric ceramic plate 31 has an outer packaging in a state in which the peripheral portions of the front and rear surfaces are elastically sandwiched between the holding spacer 42 and the pressing spacer 33, both of which are made of an elastic material. It is hold | maintained in the recessed part 411 of case 4, and there exists the 1st-3rd effect described below by this.

  The first effect is an effect as a spacer for sufficiently securing a gap larger than the amplitude when the piezoelectric ceramic plate 31 vibrates.

  The second effect is an effect as a cushion for not transmitting the vibration of the piezoelectric ceramic plate 31 to other members. In particular, in the case of the liquid crystal display module as in this embodiment, if vibration is transmitted to the liquid crystal of the liquid crystal display panel 12, the behavior of the liquid crystal molecules may be adversely affected and display defects may occur. The effect becomes more important.

  And the 3rd effect is an effect as a separator which prevents interference of the sound waves oscillated from the both sides when piezoelectric ceramic board 31 vibrates. In this case, the vibration space 4212 (see FIG. 4) secured with respect to the rear surface of the piezoelectric ceramic plate 31 (the surface facing the bottom plate 41 of the exterior case 4) is a closed space. The sound wave oscillated from can be contained. On the other hand, the pressing spacer 33 installed on the front surface of the piezoelectric ceramic plate 31 is formed in a circular shape with a part of the ring cut out and provided with an opening 331, and propagates sound waves oscillated from the front surface. The opening 331 is positioned in the power direction. That is, the opening 331 of the pressing spacer 33 communicates a space formed between the piezoelectric ceramic plate 31 and the light reflecting sheet 25 by the pressing spacer 33 with a sound guide path to be described later. The sound wave oscillated from the front surface of the plate 31 is propagated from the opening 331 to the sound guide path without interfering with the sound wave oscillated from the rear surface, and a clear sound is obtained.

  As shown in FIG. 3, of the four side plates of the outer case 4, the side plate 43 that opposes the opening 331 of the pressing spacer 33 has a convex portion 431 for forming a sound guide path for guiding sound waves. Is formed.

  Two openings 441 and 442 are respectively formed over a predetermined length on one side plate 44 of the pair of longitudinal side plates. These openings 441 and 442 are openings for drawing out the flexible wiring board 13 bonded to the liquid crystal display panel 11 and the flexible wiring board 34 for inputting sound source signals of the sound source unit 3 to the outside of the outer case 4, respectively.

  Here, the mounting assembly procedure at the finishing stage of the liquid crystal display module of the present embodiment will be described. First, the sound source unit 3 is mounted on the exterior case 4. When mounting, the piezoelectric ceramic plate 31 having the sound source signal input flexible wiring board 34 solder-bonded to the thin film electrodes 32a and 32b in advance and the pressing spacer 33 attached thereto is embedded in the case bottom plate 41. It only needs to be loaded into the holding space 4211 of the spacer 42, and the number of work steps is greatly reduced as compared with the case of mounting while positioning using an adhesive member such as a double-sided adhesive tape.

  Next, the backlight unit 2 and the liquid crystal display panel 1 are sequentially overlapped and fitted in the outer case 4 to obtain the liquid crystal display module shown in FIG. In the liquid crystal display module of the present embodiment, the wiring formation surface of the sound source signal input flexible wiring board 34 in the sound source unit 3 is the exterior case bottom plate 41 of the sound source unit 3 due to the arrangement in the electrical connection with the drive control circuit board in the applied product. It is arranged to face the inner surface. Therefore, the solder 35 electrically connecting the output side connection terminals 343a and 343b (see FIG. 3) of the sound source signal input flexible wiring board 34 and the thin film electrodes 32a and 32b on the piezoelectric ceramic plate 31 side contacts the inner surface of the bottom plate 41. However, since the outer case 4 is formed of an insulating resin material, the occurrence of a problem that a signal voltage serving as a sound source leaks through the outer case 4 is reliably prevented.

  Correspondence between the backlight unit 2 and the liquid crystal display unit 1 housed in the convex portion 431 of the side plate 43 in a state where the backlight unit 2 and the liquid crystal display unit 1 are sequentially fitted and housed in the outer case 4 to which the sound source unit 2 is mounted. The sound guide path 5 is formed so as to surround each end face on the side to be operated. The sound guide path 5 is provided to guide useful sound waves oscillated from the front surface when the piezoelectric ceramic plate 31 vibrates from the opening 331 of the pressing spacer 33 to the front surface (module front surface) side of the liquid crystal display panel 11. It has been. Accordingly, sound waves oscillated from the front surface of the piezoelectric ceramic plate 31 oscillating in accordance with the input signal voltage travel into the sound guide path 5 from the opening 331 of the pressing spacer 33, and pass through the sound guide path 5. While propagating, the sound pressure (sound volume) is amplified to some extent, that is, amplified and emitted to the display surface (front surface) side of the liquid crystal display panel 11. As a result, the viewer of the present liquid crystal display module can observe the video displayed on the liquid crystal display panel 11 and listen to clear sound related thereto.

  As described above, in the liquid crystal display module of the present embodiment, the sound source unit 3 is installed on the back surface (rear surface) side of the liquid crystal display unit 1, and sound waves emitted from the sound source unit 3 are guided to the front surface side of the liquid crystal display unit 1. Since the sound guide path 5 is formed on the side surface of the module, an increase in the area of the entire liquid crystal display module due to the provision of the speaker device can be suppressed as small as possible. As a result, reduction in size and thickness of an applied product such as a cellular phone on which the liquid crystal display module with the speaker device is mounted is promoted.

  Then, an insulating resin material is used as the material of the outer case 4, and the spacer 42 that holds the piezoelectric ceramic plate 31 of the sound source unit 2 is pre-molded with a resin material rich in elasticity, and the body portion of the outer case 4 and insert molding are performed. Since it is configured to form in a lump, the mounting operation of the sound source unit 2 can be easily performed with less man-hours, and the solder connection portion of the sound source unit 3 comes into contact with the outer case bottom plate 41 so that the audio signal passes through the outer case 4. The possibility of leakage is also eliminated.

  Further, only the useful sound wave emitted from the front surface where the pressing spacers 33 and the holding spacers 42 are disposed on the front and rear peripheral edges of the front and rear surfaces of the piezoelectric ceramic plate 31 selectively from the opening 331 is provided. Therefore, it is possible to listen to clear and accurate sound without noise while observing a high quality display on the front side of the liquid crystal display module.

  In addition, since the sound guide path 5 is formed by surrounding the exterior case side plate 42 and the side end surfaces of the liquid crystal display unit 1 and the backlight unit 2 without using a dedicated member, an increase in the number of parts is suppressed, Combined with the ease of mounting the sound source unit 3 by the insert-molded holding spacer 42, the mounting and assembling operation of the present liquid crystal display module is further simplified, and the number of manufacturing steps is further reduced.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected about the component same as the said embodiment, and the description is abbreviate | omitted.

  As shown in FIG. 5, the liquid crystal display module of the present embodiment has a rear peripheral edge of the piezoelectric ceramic plate 31 of the pair of spacers 33 and 42 that sandwich the piezoelectric ceramic plate 31 of the sound source unit 3 in the first embodiment. The holding spacer 42 that supports the portion is changed to an annular spacer 36 made of an elastic material such as urethane foam, and this is attached to the case bottom plate 41 with an adhesive member (not shown) such as a double-sided adhesive tape. ing.

  The exterior case 6 has a two-layer structure in which a wall is formed by laminating an outer surface layer 61 and an inner surface layer 62. Here, the outer surface layer 61 is formed of a metal material such as stainless steel and connected to the ground, and the inner surface layer 62 is formed of an insulating resin material such as PET (polyethylene terephthalate). Other configurations are the same as those in the first embodiment.

  According to the flat liquid crystal display module of the second embodiment configured as described above, the increase in the area of the entire liquid crystal display module due to the provision of the speaker device can be suppressed as small as possible, and the sound source signal According to the first embodiment, since the solder joint portion of the input flexible wiring board 34 is in contact with the inner surface layer 62 made of the insulating material of the outer case 6, the sound source signal does not leak through the outer case 6. In addition to the effects equivalent to the above, the liquid crystal display panel 1, the backlight unit 2 and the sound source unit 3 are substantially surrounded by a case outer surface layer formed of a conductive material and connected to the ground. Mixing of noise and emission of noise to the outside are prevented.

The present invention is not limited to the first and second embodiments described above.
In the first embodiment, one holding spacer 42 that sandwiches the piezoelectric ceramic plate 31 is implanted in the exterior case 4 by insert molding. However, the spacer for supporting the piezoelectric ceramic plate 31 is not limited to this, and is urethane foam. It is formed separately in an annular shape with an elastic material such as a pin, and a pin and an engagement hook for determining the position of this spacer are molded integrally with the exterior case, and the spacer positioned by the pin and the engagement hook is formed on the inner surface of the exterior case. It is good also as a structure stuck on.

  Further, in the second embodiment, the inner surface layer 62 made of an insulating resin material is formed on the entire inner surface of the outer case 6, but there is a possibility of conducting contact such as a solder joint portion of the flexible wiring board for sound source signal input. The insulating layer may be selectively disposed on the inner surface of the outer case made of a conductive material corresponding to the above.

  In addition, the present invention is not limited to a liquid crystal display module with a backlight, but can be widely applied to other various flat image display modules such as a reflective liquid crystal display module, an organic EL (Electro Luminescence) display, and a plasma display. Of course.

It is a perspective view which shows the liquid crystal display module as 1st Embodiment of this invention. It is typical sectional drawing which cut | disconnects and shows the said liquid crystal display module by the II-II line | wire of FIG. It is a disassembled perspective view of the said liquid crystal display module. It is a disassembled perspective view which expands and shows the positional relationship between the specific members in the said liquid crystal display module. It is typical sectional drawing corresponding to FIG. 2 which made the liquid crystal display module as 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display unit 11 Panel case 111 Display window 12 Liquid crystal display panel 121,122 Glass substrate 13 Flexible wiring board 2 Backlight unit 21 Light guide plate 22 LED
24 Optical sheet laminated body 25 Light reflection sheet 3 Sound source unit 31 Piezoelectric ceramic plates 32a and 32b Thin film electrode 33 Press spacer 34 Sound source signal input flexible wiring board 35 Solder 4 and 6 Exterior case 41 Bottom plate 411 Recess 42 Holding spacer 421 Cylindrical portion 422 Flange portions 43, 44 Side plate 431 Convex portion 5 Sound guide path 61 Outer surface layer 62 Inner surface layer

Claims (6)

A sound source element that emits sound waves by a piezoelectric ceramic plate that is conductively connected to one end of a predetermined electrode;
A case for storing the display panel and the sound source element so that the sound source element is located between the display panel and the bottom plate part, and having a bottom plate part;
A flexible wiring board joined to the other end of the electrode by solder;
With
The solder is provided on the surface of the flexible wiring board facing the bottom plate portion so as to protrude toward the bottom plate portion,
The flat image display module , wherein the bottom plate portion is formed of an insulating resin material in a region facing the solder . The sound source element includes a first spacer having a shape in which an opening is formed in a part of a ring.
The flat image display module according to claim 1, wherein the first spacer is disposed between the piezoelectric ceramic plate and the display panel . The case has a side wall portion formed between a side surface of the display panel and a space as a sound guide path for guiding a sound wave emitted from the sound source element in a predetermined direction.
The image display module according to claim 2, wherein the first spacer is disposed so that the opening portion faces the direction of the sound guide path . The sound source element has a second spacer in which a predetermined region is formed in a cylindrical shape,
The image according to any one of claims 1 to 3, wherein the second spacer is disposed so that the cylindrical region is positioned between the bottom plate portion and the piezoelectric ceramic plate. Display module. The image display module according to claim 4, wherein the second spacer is formed of an insulating material having a lower elastic coefficient than the resin material . The image display module according to claim 1 , wherein a backlight for irradiating the display panel with light is disposed between the display panel and the sound source element .

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