JPH05216029A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain the liquid crystal display device which has superior quietness and provides a good sensation of use by eliminating undesirable vibration and a noise which are generated when an EL is driven. CONSTITUTION:A liquid crystal display panel 1 and a printed board 2 which are electrically connected through a rubber connector are assembled in one body by using a metallic frame 5. Electroluminescence(EL) for a back light is mounted detachably in the space 28, constituted between the liquid crystal display panel 1 and printed board 2, from one side of the metallic frame 5. At this time, the EL 3 is curved so that the apparent thickness is larger than the height of the space, and then elastically held between the members constituting the space.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device in which electroluminescence for backlight (hereinafter abbreviated as EL) is detachably mounted between a liquid crystal display panel and a printed circuit board, and more particularly, The present invention relates to an EL holding structure.

[0002]

2. Description of the Related Art Conventionally, a liquid crystal display device using an EL as a backlight of a liquid crystal display panel is known. An example of this type of conventionally known liquid crystal display device will be described below with reference to FIGS. 3 and 4. FIG. 3 is an exploded perspective view of a liquid crystal display device according to a conventional example, and FIG. 4 is a cross-sectional view seen from a side direction thereof.

As shown in FIG. 3, the liquid crystal display device of this embodiment mainly includes a liquid crystal display panel 1 and a printed circuit board 2.
EL3, a rubber connector 4 for electrically connecting the liquid crystal display panel 1 and the printed circuit board 2, and a metal frame 5 for integrally assembling these members.

In the liquid crystal display panel 1, liquid crystal is sealed between an upper electrode substrate 11 and a lower electrode substrate 12 which is slightly smaller than the upper electrode substrate 11, and polarizing plates 13 and 14 are attached to the surfaces of both electrode substrates 11 and 12, respectively. The terminal portion 1 of the upper electrode substrate 11
Electrode terminal groups (not shown) for external connection are formed at equal intervals on 1a.

A circuit (not shown) for driving the liquid crystal display panel 1 is provided on the printed circuit board 2, and a connection terminal 15 is formed on a part of the circuit with the same pitch as the electrode terminal group. .. Further, the printed board 2 is formed with a notch 16 for fixing the metal frame 5 and an engagement hole 17 for engaging a fixture 18 attached to the EL 3.

The rubber connector 4 has a laminated structure in which insulating layers 4a and conductive layers 4b are alternately laminated along the longitudinal direction and at the same pitch as the electrode terminal group and the connection terminal 15, and the conductive layer is formed. The layer 4b portion is interposed between the electrode terminal group and the connection terminal 15 and brought into close contact with each other so that conduction can be achieved.

The EL3 is a bag-shaped body obtained by joining the peripheral portions of a sheet-shaped transparent electrode member and a lower electrode member with a light-emitting body such as ZnS-Mn or ZnS-Cu enclosed therein. A lead wire 3a connected to the transparent electrode and the lower electrode is drawn out from one side edge. The EL3 applied to the liquid crystal display device of this example is, as shown in the figure,
It is shaped like a plane. The lead wire 3a is for connecting the EL3 to an external device, and has an EL3 at one end.
Is attached to the lead wire 3a, and a connector 19 for connecting to an external device is connected to the other end. As shown in FIG. 4, an elastic arm 20 is formed on the fixture 18, and the elastic arm 20 is formed.
An engaging protrusion 20a for engaging with the engaging hole 17 is formed at the tip of the.

The metal frame 5 integrally assembles the liquid crystal display panel 1, the printed circuit board 2 and the rubber connector 4, and has a front surface having an opening 21 for exposing the display surface of the liquid crystal display panel 1. It is composed of a portion 22, a side surface portion 23 formed by standing up the four sides of the front surface portion 22 in one direction, and a leg piece 24 extending from the tip end portion of the side surface portion 23. The leg piece 24 includes a narrow connecting portion 25 and the connecting portion 25.
It is formed in an inverted T shape with a wide engaging portion 26 formed at the tip of the. Incidentally, reference numeral 27 in the drawing is E
The notch for inserting the fixing tool 18 formed in the side surface portion 23 on the L3 insertion side is shown.

The method of assembling this liquid crystal display device will be described below. First, the liquid crystal display panel 1 and the printed circuit board 2
A rubber connector 4 is interposed between the electrode terminal group of the liquid crystal display panel 1 and the connection terminal 15 of the printed circuit board 2.
The conductive layer 4b of the rubber connector 4 is aligned with each other. Next, the metal frame 5 is attached to the surface of the liquid crystal display panel 1,
The leg pieces 24 of the metal frame 5 are inserted into the cutout portions 16 formed in the side edge portions of the printed circuit board 2. Thereafter, the metal frame 5 is pressed in the compression direction of the rubber connector 4, the connecting portion 25 of the leg piece 24 protruding from the lower surface of the printed circuit board 2 is twisted, and the engaging portion 26 is compressed while the rubber connector 4 is compressed.
Engage the back side of. As a result, the electrode terminal group of the liquid crystal display panel 1 and the connection terminals 15 of the printed board 2 are electrically connected via the conductive layer 4b of the rubber connector 4. Further, as shown in FIG. 4, a space 28 corresponding to the thickness of the compressed rubber connector 4 is formed between the liquid crystal display panel 1 and the printed circuit board 2. Of course, this space 28
The height H of the EL3 is formed to be slightly larger than the thickness T of the EL3 so that the EL3 can be easily attached and detached. Finally, the EL 3 shaped like a flat plate is inserted into the space 28, and the fixture 1 is inserted into the engagement hole 17 formed in the printed board 2.
The EL3 is fixed at a predetermined position by engaging the engaging protrusion 20a formed on the EL8.

[0010]

By the way, the EL3 is
When the driving frequency is too low, sufficient brightness cannot be obtained, and when the driving frequency is too high, the life is shortened. Therefore, in consideration of these, the inverter is generally driven with a frequency of about 500 Hz to 1 KHz. It vibrates slightly at this frequency. As described above, in the conventional technology,
EL3 shaped like a flat plate has a larger space 28
Since it is loosely fitted in the inside, other parts except the lead-out side of the lead wire 3a fixed to the printed circuit board 2 via the fixture 18 freely vibrate and collide with the liquid crystal display panel 1 and the printed circuit board 2. Cheap. For this reason, an inconvenience is likely to occur such that abnormal noise is generated, the quietness is impaired, and the usability deteriorates.

In order to eliminate such inconvenience, EL3
The development of a technology to absorb the vibration of the subject becomes an issue. of course,
The problem can be solved by interposing a vibration damping material between the EL 3 and the liquid crystal display panel 1 and the printed circuit board 2, but the number of parts becomes large and the assembly process becomes complicated, resulting in high cost of the device. This is not preferable because it causes another inconvenience.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a liquid crystal display device which is inexpensive, excellent in quietness, and good in usability.

[0013]

In order to solve the above-mentioned problems, the present invention assembles a liquid crystal display panel and a printed circuit board, which are electrically connected via a rubber connector, integrally with a metal frame, In a liquid crystal display device in which a backlight EL is detachably mounted in a space formed between a panel and a printed circuit board, the EL is curved so that its total thickness is apparently higher than that of the space. The elastic force is held between the members forming the space.

[0014]

[Function] EL has flexibility and some elasticity,
When an external force is applied, it easily plastically deforms in that direction,
It is elastically deformed to some extent from the molded shape. Therefore, when this was curved so that its total thickness was apparently made larger than the height of the space and was inserted into the space, a part was arranged on the printed circuit board and another part was arranged opposite to this. It is brought into contact with the liquid crystal display panel or the metal frame, and is elastically held between these members. Therefore, the unauthorized vibration and noise when the EL is driven is suppressed, the quietness is improved, and the usability is improved. By appropriately adjusting the degree of adhesion between the EL and each member forming the space, it is possible to completely eliminate the false vibration and noise. The EL curve molding can be easily performed manually without using a special device, and thus the cost of the device is not increased.

[0015]

FIG. 1 is a sectional view of a liquid crystal display device according to an embodiment as seen from the side, and FIG. 2 is a perspective view showing an example of an EL applied to the liquid crystal display device of this embodiment. In these figures, the same reference numerals are displayed in the portions corresponding to the above-mentioned figures.

As shown in FIG. 2, in this example, the end side orthogonal to the lead-out side is bent in an arc shape, and the apparent total thickness S is the height H of the space 28 (see FIG. EL3 that is shaped larger than (see 1) is used. When the EL3 is curved and formed, it is not necessary to use a special forming device, and the EL3 formed in a flat plate shape can be formed simply by urging both ends inward with fingers. As shown in FIG. 1, the EL 3 is formed to have a length such that the lead-out side end of the lead wire 3a projects outward from the metal frame 5 when inserted to a predetermined position in the space 28. Has been done. Other parts are applied to the device according to the conventional example.
It is formed similarly to L. Further, as the other members constituting the liquid crystal display device, such as the liquid crystal display panel 1, the printed circuit board 2, the rubber connector 4, and the metal frame 5, the same members as described in the conventional example are used.

Also in the liquid crystal display device of this example, the liquid crystal display panel 1, the printed board 2, the rubber connector 4, and the metal frame 5 are provided.
After integrally combining and, EL3 with the light emitting surface facing the liquid crystal display panel 1 side is inserted into the space 28 from the end side on the non-connection side of the lead wire 3a to assemble the liquid crystal display device with EL. As described above, the EL3 is formed so that the apparent total thickness S is larger than the height H of the space 28. Therefore, when the EL3 is inserted into the space 28 from the end side on the lead wire non-connection side, the upper and lower protrusions are formed. Is in close contact with the printed circuit board 2 and the liquid crystal display panel 1 or the metal frame 5 that form the space 28. Since the contact force is as large as the elastic force of the EL3, the insertion of the EL3 becomes difficult. There is no.

The EL 3 is inserted to a predetermined position in the space 28, and the fixture 1 is inserted into the engagement hole 17 formed in the printed board 2.
The assembly of the liquid crystal display device is completed by engaging the engaging projections 20a formed on the substrate 8. At this time, in the liquid crystal display device of the present embodiment, as shown in FIG. 1, the EL3 is brought into contact with the printed circuit board 2 at its substantially central portion, and the liquid crystal display panel 1 is brought into contact with the lead wire non-connecting side edge. Further, the end side on the lead wire connection side is connected to the printed circuit board 2 via the fixture 18.
And the EL 3 is elastically held in the space 28.
Therefore, the improper vibration and noise generated when the EL is driven are absorbed by the elastic force acting between the EL 3 and the printed circuit board 2, etc., and the quietness of the liquid crystal display device is improved and the usability is improved. Get better By appropriately adjusting the degree of contact between the EL3 and each member forming the space 28, it is possible to completely eliminate the false vibration and noise. Further, since the EL3 can be easily formed by bending manually, the cost of the apparatus does not increase.

The gist of the present invention resides in that the EL3 is elastically held in the space 28, and the elastic force absorbs the improper vibration accompanying the driving of the EL3.
The shape of No. 3 is not limited to that of the above-mentioned embodiment, and can be formed into any shape other than that of the embodiment as long as the above-mentioned function can be exhibited. Further, the specific configurations of the liquid crystal display panel 1, the printed circuit board 2, the EL 3, the rubber connector 4, and the metal frame 5 are not limited to those in the above embodiment. Further, members such as the fixture 18 and the connector 19 can be appropriately discarded as necessary regardless of the above-mentioned embodiment. These can be arbitrarily modified in design without departing from the scope of the present invention.

[0020]

As described above, according to the present invention,
The EL is elastically held between the printed circuit board and the liquid crystal display panel or the metal frame, and an unauthorized vibration occurs when the EL is driven,
Since the noise is absorbed by the elastic force acting between these members, the quietness of the liquid crystal display device is improved and the usability is improved. Further, since the EL bending molding can be easily performed manually, the cost of the apparatus does not increase.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a liquid crystal display device according to an embodiment as seen from a side direction.

FIG. 2 is a perspective view of an EL applied to the liquid crystal display device according to the embodiment.

FIG. 3 is an exploded perspective view of a liquid crystal display device according to a conventional example.

FIG. 4 is a cross-sectional view of a liquid crystal display device according to a conventional example as seen from a side surface direction.

[Explanation of symbols]

 1 Liquid crystal display panel 2 Printed circuit board 3 EL 3a Lead wire 4 Rubber connector 5 Gold frame

Claims (1)

[Claims] 1. A liquid crystal display panel and a printed circuit board, which are electrically connected via a rubber connector, are integrally assembled with a metal frame, and a back space is provided in a space formed between the liquid crystal display panel and the printed circuit board. In a liquid crystal display device in which an electroluminescence for a light is detachably mounted, the electroluminescence is curved so that its apparent total thickness is larger than the height of the space, and between the respective members forming the space. A liquid crystal display device characterized by being elastically held by.