JP5019604B2 - Liquid crystal display - Google Patents

Description

  The present invention relates to a liquid crystal display device in which a flexible printed circuit board on which circuit components for driving a liquid crystal display panel are mounted is curved to connect the liquid crystal display panel and an illumination member.

  The liquid crystal display device includes a liquid crystal display panel, an illumination member that emits light from the liquid crystal display panel, and a flexible printed circuit board on which circuit components that drive the liquid crystal display panel are mounted. And a lighting member.

5 and 6 show an example of such a conventional liquid crystal display device. The liquid crystal display panel P, an illumination member that irradiates light to the liquid crystal display panel P, and the liquid crystal display panel P and the illumination member are connected. And a flexible printed circuit board (FPC board), and the lower illumination member emits light toward the upper liquid crystal display panel P. The light guide plate 13 and other optical films are arranged on the frame F of the illumination member (light guide plate 3), and the liquid crystal display panel P is incorporated above the frame F. In addition, a light source (LED or the like) 12 c that irradiates light to the light guide plate 13 is mounted on the flexible printed circuit board 12. The flexible printed circuit board 12 has one end 12a bonded to the connecting portion Pka of the liquid crystal display panel P (using electrical bonding with the liquid crystal display panel and then using an adhesive, heating means, etc.) And is bent to the back side while curving in an arc shape with the bonded portion as a base point. And the other end side 12b is affixed on the double-sided tape R affixed on the lower surface Fk3 of the said frame F, and is arrange | positioned at the back surface of the light-guide plate 13 which is one part of the liquid crystal display panel P and an illuminating member. That is, the flexible printed circuit board 12 is attached so as to draw a substantially semicircle through a gap B having a predetermined interval at a notch portion Fk provided on one side wall Fa of the frame F of the illumination member. The light source 12c mounted on the flexible printed circuit board 12 is disposed at a predetermined position on the light guide plate 13 so that the light guide plate 3 can irradiate the liquid crystal display panel P with light. An example of the liquid crystal display device having the above configuration is Japanese Patent Laid-Open No. 9-138387.
JP-A-9-138387

  By the way, most of the flexible printed circuit boards 12 are film substrates in which a plurality of polyimide films are bonded together and a copper foil wiring pattern is provided therebetween. Therefore, if the film substrate is maintained in a bent state so as to draw a semicircle, the polyimide film or the copper foil tries to return to the original flat state, and a strong repulsive force is generated. And this repulsive force acts large on the adhesion part of flexible printed circuit board 12 and liquid crystal display panel P, or the adhesion part of flexible printed circuit board 12 and frame F of an illuminating member. For example, when the adhesive force between the flexible printed circuit board 12 and the frame F is weak and loses the repulsive force, the flexible printed circuit board 12 may be rolled up from the attached portion and peeled off from the frame F (FIG. 7 ( a)). Thereby, inconveniences such as each light source 12a mounted on the flexible printed circuit board 12 coming off from the fitting portion 13a of the light guide plate 13 occur. On the contrary, when the adhesive force of the adhesion part of the flexible printed circuit board 12 and the liquid crystal display panel P is weak and loses the said repulsive force, the flexible printed circuit board 12 will rise from this adhesion part, and will peel from the liquid crystal display panel P. There is a fear (FIG. 7B). Further, even when the adhesive force between the flexible printed circuit board 12 and the liquid crystal display panel P and the adhesive force between the flexible printed circuit board 12 and the frame F are not inferior to the repulsive force, the repulsive force causes the flexible printed circuit board 12 itself. May float off the frame F and come off. That is, the repulsive force of the flexible printed circuit board P is superior to the force that the frame F tries to hold the liquid crystal display panel P, and the flexible printed circuit board P tries to return to the original flat state while being adhered to the liquid crystal display panel P. There is a fear that the liquid crystal display panel P may come off from the frame F due to rising (FIG. 7C).

  Further, the connecting operation of the flexible printed circuit board 12 is attached so as to draw a substantially semicircular shape through a gap B that is maintained at a predetermined distance from the one side wall Fa of the frame F. Since it was performed against this, it was accompanied by the difficulty of connecting work.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal display device that suppresses the repulsive force of a flexible printed circuit board, maintains the connection stability of the flexible printed circuit board, and facilitates the connecting operation of the flexible printed circuit boards.

The liquid crystal display device of the present invention, in the liquid crystal display device by bending the flexible printed board circuit components for driving the liquid crystal display panel is mounted to couple the illumination member and the liquid crystal display panel, wherein the frame of the illumination member provided contact portion for contacting a flexible printed circuit board, is configured to the flexible printed circuit board Ru bent while in contact along the contact portion,
The contact portion includes a first contact portion formed by cutting out the upper surface of the frame of the lighting member flatly, and one end side of the flexible printed circuit board via a double-sided tape in the first contact portion. And the other end side of the flexible printed circuit board is connected to the lower surface of the frame of the lighting member via the double-sided tape . Here, the contact portion, the entire point bending of the flexible printed circuit board may be a contact portion that contacts.

  According to the present invention, when the liquid crystal display panel and the illumination member are connected by the flexible printed circuit board, the flexible printed circuit board is bent while being brought into contact with the contact part, so that the conventional flexible printed circuit board is not interposed through the contact part. Compared with the case where the cross section is attached in an arc shape while maintaining a gap, the repulsive force of the flexible printed circuit board can be suppressed, and the connecting work is also easy.

  According to the present invention, the upper surface of the frame of the lighting member is cut out flat to form the first contact portion, whereby a double-sided tape can be disposed on the contact portion. And a flexible printed circuit board and the said contact part are made to contact via this double-sided tape, and sticking fixation on the frame upper surface of a flexible printed circuit board is attained. Here, as with conventional liquid crystal display devices, if a double-sided tape is placed on the lower surface of the frame of the lighting member, and this portion is also attached and fixed to the flexible printed circuit board, the flexible printed circuit board is mounted on the frame of the lighting member. It is firmly fixed on the lower surface and does not rise due to the repulsive force generated in the flexible printed circuit board.

The liquid crystal display device of the present invention is a liquid crystal display device in which a flexible printed circuit board on which a circuit component for driving a liquid crystal display panel is mounted is curved to connect the liquid crystal display panel and the illumination member. A contact portion that contacts the flexible printed circuit board is provided, and the flexible printed circuit board is bent while being in contact with the flexible printed circuit board,
To the contact portion, there is a first contact portion formed by notching the flat upper surface of the frame of the illumination member and the contact portion, the frame of the lighting member in cross-section an acute angle shape so as there is a second contact portion formed on, characterized by Tei Rukoto folded said flexible printed circuit board while contacting the second contact portion of the acute angle.

  According to the present invention, when the flexible printed circuit board is bent while being brought into contact with the acute-angle contact portion, the bending angle becomes abrupt and the repulsive force of the flexible printed circuit board can be further suppressed. The flexible printed circuit board is bent sharply at the acute-angled contact portion. However, if the flexible printed circuit board is folded using a layer on which the wiring of the flexible printed circuit board is not applied, the wiring of the flexible printed circuit board may be damaged by bending. There is no problem.

The present invention, in the contact portion, the frame of the illumination member whose cross-section has a second contact portion which is formed to be acute-angled, while in contact with the second contact portion of the acute-angled the flexible printed circuit board is bent Tei Rukoto are preferred.

  According to the present invention, the flexible printed circuit board is bent along the contact portions of both the first contact portion and the second contact portion, and a double-sided tape is arranged on the upper and lower surfaces of the frame of the lighting member. Since the lower surface can be fixed to the flexible printed circuit board, the repulsive force of the flexible printed circuit board can be further suppressed.

  According to the liquid crystal display device of the present invention, when the liquid crystal display panel and the illumination member are connected by the flexible printed circuit board, the flexible printed circuit board is bent while being brought into contact with the contact portion. Can be suppressed. Thereby, it becomes possible to prevent the flexible printed circuit board from being detached from the liquid crystal display panel or the illumination member. In addition, since the flexible printed circuit board is bent while being brought into contact with the contact portion, it is easier to connect the flexible printed circuit board than in the conventional case where the flexible printed circuit board is bent into a semicircular shape through a gap. Is planned.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of the present embodiment. FIG. 2 is a cross-sectional view of one side end side of the liquid crystal display device 1 of the present embodiment. A liquid crystal display device 1 according to the present embodiment is used for a mobile phone, and includes a liquid crystal display panel P, an illumination member (light guide plate 3) for irradiating light to the liquid crystal display panel P, and the liquid crystal display panel P. A backlight that includes a flexible printed circuit board (FPC board) 2 that connects an illumination member (light guide plate 3) and irradiates the upper liquid crystal display panel P upward with the lower illumination member (light guide plate 3). There is a method.

  In the liquid crystal display panel P, a pair of transparent substrates Pk, Pk on which display electrodes are laid are opposed to each other at an appropriate interval, and a liquid crystal material is sealed around the transparent substrates Pk, Pk with a sealing material at the interval. Composed. The pair of transparent substrates Pk and Pk is an array substrate Pk and a counter substrate Pk. The array substrate Pk has a thin film transistor (TFT), a transparent pixel electrode (ITO), etc. in a matrix on the surface of a glass substrate which is an insulating substrate. The counter substrate Pk is formed with a counter electrode or the like formed on the back surface of a glass substrate which is an insulating substrate. In the array substrate Pk, a connecting portion Pka that connects one end side 2a of the flexible printed circuit board 2 is formed wider than the counter substrate Pk.

  The flexible printed circuit board 2 is mounted with circuit components for driving the liquid crystal display panel P, and connects the liquid crystal display panel P and the illumination member (light guide plate 3). Here, it is a multilayer film substrate in which a plurality of polyimide films are bonded together, and a copper foil wiring pattern is provided therebetween. In addition, an LED that is a light source 2c is mounted on the lower surface of the flexible printed circuit board 2.

  The illumination member (light guide plate 3) includes a rectangular frame F, and an optical film such as the light guide plate 3 is laid in the frame F, and the liquid crystal display panel P is incorporated therein. Below the frame F (lowermost layer), the light guide plate 3 is exposed, and a hole 3c for fitting the light source 2c mounted on the flexible printed circuit board 2 from below is formed. The light guide plate 3 is made of a material such as acrylic having good optical characteristics represented by transmittance and refractive index necessary for light transmission. Therefore, if the other end side 2b where the light source 2c of the flexible printed circuit board 2 is arranged is curved and the light source 2c is fitted into the hole 3a of the light guide plate 3 exposed on the lower surface, light is introduced into the light guide plate 3. And constitutes the substance as the illumination member. In addition, as an illumination member (light guide plate 3), there is one in which the light guide plate 3 is not exposed and is covered with a cover member. In such a configuration, the light source 2c is often mounted on another independent flexible printed circuit board, and is electrically connected by being connected to the adapter of the flexible printed circuit board 2 on the liquid crystal display panel P side. Some are completed. Even in the liquid crystal display device having such a configuration, in order to connect the flexible printed circuit board 2 to another unit, the flexible printed circuit board 2 needs to be fixed in a state of being bent to the lower surface of the liquid crystal display device. The following configuration in the present liquid crystal display device can be applied.

  On one side wall Fa of the rectangular frame F, a notch Fk is provided. The notch Fk is for connecting the flexible printed circuit board 2 by bending the liquid crystal display panel P and the illumination member (light guide plate 3) close to each other, and constitutes an upper surface Fk1, a side surface side Fk2, and a bottom surface Fk3. In this way, one side wall Fa of the frame F is cut out. From the upper surface Fk1 to the side surface side Fk2, the cross section is formed in a substantially circular arc shape (smooth curved shape), and the corner portion a1 composed of the side surface side Fk2 and the bottom surface Fk3 is formed in an acute angle shape. The contact portion a1. The upper surface Fk1 of the notch Fk is formed flat to be the first contact portion Fk1, and a stable posture when the one end side 2a of the flexible printed circuit board 2 is attached via the second double-sided tape R2. Is secured. On the other hand, the other end 2b of the flexible printed circuit board 2 is attached to the lower surface Fk2 of the notch Fk via the first double-sided tape R1. Here, the one end side 2a of the flexible printed circuit board 2 refers to a portion from an adhesion portion with the connection portion Pka of the liquid crystal display panel P to a contact portion with the upper surface Fk1 of the frame F. Further, the other side 2a of the flexible printed circuit board 2 refers to the boundary line T between the upper surface Fk1 and the side surface side Fk2 of the frame F to the end portion bent to the lower surface Fk3 of the frame F (FIG. 1). reference).

  Here, when the second double-sided tape R2 is attached to the upper surface Fk1 of the notch Fk, the upper surface R2a of the second double-sided tape R2 is the upper surface of the array substrate Pk when the liquid crystal display panel P is incorporated into the frame F. (Connecting part) It is set to be flush with Pka. Accordingly, one end 2a of the flexible printed circuit board 2 is connected to not only the upper surface Pka of the flush array substrate Pk but also the upper surface R2a of the second double-sided tape R2, so that there is an extra gap as in the conventional example. Without causing B, the adhesion between the flexible printed circuit board 2 and the second double-sided tape R2 can be made strong.

  The corner portion a1 constituted by the side surface side Fk2 and the lower surface Fk3 has a sharp cross section (FIG. 2). This is because the flexible printed circuit board 2 is bent at the corners a <b> 1 in order to make it difficult for a repulsive force to return to the original flat state. The corner portion a1 configured by the side surface side Fk2 and the lower surface Fk3 of the present embodiment can be made less likely to generate a repulsive force as the angle θ1 is smaller (smaller than 90 degrees). For this reason, when the one end side 2a of the flexible printed circuit board 2 is bent in contact with the corner part a1, depending on the angle of the corner part a1, the flexible printed circuit board 2 is bent so as to be creased. .

  Therefore, in the liquid crystal display device 1 having the above configuration, when the flexible printed circuit board 2 is connected to the liquid crystal display panel P and the illumination member (light guide plate 3), first, the light guide plate is attached to the frame F of the illumination member (light guide plate 3). 3 is the lowest layer, and other optical films are laid on it. Then, one end 2a of the flexible printed circuit board 2 is bonded to the upper surface Pka of the array substrate Pk (after making electrical connection with the array substrate Pk, bonding with an adhesive, pressure bonding using a heating means, or the like, or After adhering by adhering with a double-sided tape or the like (the upper diagram in FIG. 1), the liquid crystal display panel P is assembled. Next, the second double-sided tape R2 is interposed on the upper surface Fk1 of the notch Fk, and the upper surface R2a and the lower surface of the one end side 2a of the flexible printed circuit board 2 are attached. When pasted in this way, one end 2a of the flexible printed circuit board 2 is pasted not only on the top surface (the connecting portion of the liquid crystal display panel P) Pka of the flush array substrate Pk but also on the top surface 8a of the second double-sided tape 8. Because it is attached, it is connected and fixed in a stable posture.

  Next, the other end side 2b of the flexible printed circuit board 2 is bent and brought into contact with the acute angle corner a1, and the other end side 2b of the flexible printed circuit board 2 is bent sharply into an acute angle to be flexible. The printed board 2 is attached to the lowermost light guide plate 3 of the illumination member (light guide plate 3). That is, by fixing the other end 2b of the flexible printed circuit board 2 to the lower surface of the frame F by the first double-sided tape R1 disposed on the lower surface of the frame F, the flexible printed circuit board 2 is illuminated with the illumination member (light guide plate 3). (Fig. 5). At this time, the light source 2 c is fitted into the hole 3 a of the light guide plate 3 described above, and the light source 2 c is arranged on the light guide plate 3. When the other end side 2b of the flexible printed circuit board 2 is bent and bent sharply at such an acute angle as described above, the other end side 2b of the flexible printed circuit board 2 is actively bent so that a crease is formed. The For this reason, the repulsive force can be suppressed from the conventional case where the flexible printed circuit board 2 is attached to the light guide plate 3 while maintaining a certain distance from the gap B. In addition, by arranging the double-sided tapes R2 and R1 on the upper and lower surfaces Fk1 and Fk3 of the frame F of the lighting member, the upper and lower surfaces Fk1 and Fk3 of the frame F can be adhered and fixed to the flexible printed circuit board 2. The repulsive force of the flexible printed circuit board 2 can be further suppressed. The flexible printed circuit board 2 is bent at the acute-angled contact portion a1, but the flexible printed circuit board 2 is bent using a layer (a boundary portion between the first layer and the second layer) where the wiring of the multilayer flexible printed circuit board 2 is not applied. For example, there is no problem that the wiring of the flexible printed circuit board 2 is damaged by bending.

  Here, as another example of the present embodiment, as shown in FIG. 3, the corner portion a2 formed by the side surface side Fk2 and the upper surface Fk1 may be configured to have an acute angle. In the example shown in FIG. 3, the second double-sided tape R2 is provided, but the second double-sided tape R2 is not always necessary, and only the corner portion a2 may be used. Further, as shown in FIG. 4, it is possible to prevent the gap B from occurring. In the example shown in FIG. 4, the second double-sided tape R2 extends from the upper surface Fk1 of the notch Fk to the position of the corner a1 along the side surface Fk2. Further, the first double-sided tape R1 also reaches the position of the corner a1. Therefore, the first and second double-sided tapes R1 and R2 are bonded without a gap B, and the repulsive force of the flexible printed circuit board 2 is suppressed to the extent that it disappears. Moreover, in the example shown in FIG. 4, since the flexible printed circuit board 2 should just be connected so that there may be no gap B and it may follow the notch Fk, a connection work is still easier.

  As described above, in the present embodiment, the flexible printed circuit board 2 is coupled through the first and second double-sided tapes R1 and R2, and the flexible printed circuit board 2 is coupled and fixed while being contacted by the acute corner portions a1 and a2. Although the case where it does is demonstrated as an example, it is possible to suppress the repulsive force in the connection of the flexible printed circuit board 2 only in any one of the above, and it is included in this invention.

  In the first embodiment of the present invention, the description is applied to the backlight type liquid crystal display device 1 in which the illumination member (light guide plate 3) is disposed below the liquid crystal display panel P. The form may be a so-called front light system, or may be a liquid crystal display device in which the liquid crystal display panel P is arranged on both upper and lower surfaces of the frame F, that is, a circuit component for driving the liquid crystal display panel. Can be widely applied to a liquid crystal display device that bends a flexible printed circuit board on which the liquid crystal display panel is mounted and connects the liquid crystal display panel and the illumination member.

It is a perspective view which shows the liquid crystal display device which is one embodiment of this invention. It is sectional drawing which shows the structure of the one side end side of the liquid crystal display device of the said one Embodiment. It is sectional drawing which shows the other example of the said one embodiment. It is sectional drawing which shows the other example of the said one embodiment. It is a perspective view which shows the conventional liquid crystal display device. It is sectional drawing which shows the conventional liquid crystal display device. It is a figure explaining the contact failure of the conventional flexible printed circuit board.

Explanation of symbols

1 Liquid crystal display device,
2 flexible printed circuit board, 2a one end side, 2b other end side, 2c light source,
3 light guide plate (illumination member), 3a hole,
a1, a2 corner (second contact portion, contact portion),
B gap,
F frame,
One side wall of Fa frame F,
Fk frame notch,
Fk1 upper surface of the notch (first contact portion, contact portion),
Fk2 The side of the notch,
Fk3 The bottom surface of the notch,
P liquid crystal display panel, connecting portion of Pka liquid crystal display panel,
R1 first double-sided tape,
R2 second double-sided tape, R2a top surface of second double-sided tape,
T The boundary line between the upper surface and the side surface of the notch,

Claims (3)

In the liquid crystal display device for connecting a flexible printed board circuit components for driving the liquid crystal display panel is mounted by bending with the liquid crystal display panel and the lighting member, the contact portion contacting the flexible printed circuit board to the frame of the illumination member the provided is a configuration in which the flexible printed circuit board Ru bent while in contact along the contact portion,
The contact portion includes a first contact portion formed by cutting out the upper surface of the frame of the lighting member flatly, and one end side of the flexible printed circuit board via a double-sided tape in the first contact portion. And the other end side of the flexible printed circuit board is connected to the lower surface of the frame of the lighting member via a double-sided tape . In a liquid crystal display device that connects a liquid crystal display panel and an illumination member by curving a flexible print substrate on which circuit components for driving the liquid crystal display panel are mounted, a contact portion that contacts the flexible print substrate with a frame of the illumination member And is configured to bend while contacting the flexible printed circuit board along the contact portion,
To the contact portion, there is a first contact portion formed by notching the flat upper surface of the frame of the illumination member and the contact portion, the frame of the lighting member in cross-section an acute angle shape so as there is a second contact portion formed on the liquid crystal display device comprising Tei Rukoto folded said flexible printed circuit board while contacting the second contact portion of the acute angle. To the contact portion, the frame of the illumination member whose cross-section has a second contact portion which is formed to be acute-angled, the flexible printed circuit board while contacting the second contact portion of the acute angle shape folded liquid crystal display device according to claim 1, wherein the imperial Rukoto.

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