JP4515599B2 - Backlight integrated liquid crystal display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal display device in which a plurality of lead terminals formed on electrode terminal portions of a liquid crystal display element are connected to a power supply side wiring board via a flexible wiring board, and in particular, a liquid crystal display element and a power supply The present invention relates to an improvement of a backlight-integrated liquid crystal display device in which a backlight is disposed between side wiring boards.
[0002]
[Prior art]
First, an example of a general liquid crystal display element in this type of backlight-integrated liquid crystal display device will be described with reference to FIG.
[0003]
FIG. 2 shows a color filter type color liquid crystal display device, which has two transparent substrates 1A and 1B made of a glass-like material and arranged in parallel with a distance therebetween. The outer periphery between the transparent substrates 1A and 1B is sealed with a sealing material 2. Among these, the transparent common electrode 3A is disposed so as to be in close contact with the lower surface of one transparent substrate 1A located above, and the non-display area is covered below the transparent common electrode 3A. A light-shielding film 4 is disposed on the surface.
[0004]
An alignment film 6A that controls the alignment of liquid crystal molecules according to the voltage applied between the electrodes is disposed below the light shielding film 4 so as to be in close contact therewith. Further, a polarizing plate 7A is disposed on the upper surface of the glass substrate 1A.
[0005]
On the other hand, a transparent segment electrode 3B is disposed on the upper surface of the transparent substrate 1B located below, and a color filter film 5 is disposed above the transparent segment electrode 3B. Various methods such as a printing method, an electrodeposition method, a dyeing method, and a pigment dispersion method are conventionally known as methods for forming the color filter film 5. Further, an alignment film 6B is disposed on the color filter film 5 so as to be in close contact therewith. Further, a polarizing plate 7B is disposed on the lower surface of the transparent substrate 1B.
[0006]
The liquid crystal 8 is enclosed in a sealed space surrounded by the transparent substrates 1A and 1B and the sealing material 2, and further, the distance between the transparent substrates 1A and 1B is kept accurately and constant. A plurality of spherical or columnar spacers 9 are interposed between the alignment films 6A and 6B.
[0007]
The transparent segment electrode 3B on the upper surface of the transparent substrate 1B is led out on the lower surface of the transparent substrate 1A via a conductive member (not shown) contained in the sealing material 2 and the like. Each lead terminal 3C of each electrode 3A, 3B is formed in the right end part in FIG. 3 of the lower surface of this transparent substrate 1A.
[0008]
On the other hand, an electric circuit 13 is formed on the base film 12 of the flexible wiring board 11 shown in FIG. 4, and the electrodes 3A and 3B are connected to lead terminals 13A formed at the ends of the electric circuit 13. Each lead terminal 3C is connected. Further, an LSI 14 for controlling the liquid crystal display element is mounted on the electric circuit 13 of the flexible wiring board 11. The flexible wiring board 11 is formed with a curved portion 15 to reduce the plane area of the liquid crystal display device, and then extends below the liquid crystal display element 10 as shown in FIG. And connected to a rigid power supply side wiring board 16 located below the liquid crystal display element 10 via lead terminals. Further, the power supply side wiring substrate 16 and the liquid crystal display element 10 are positioned so as to face each other.
[0009]
By the way, in the backlight integrated liquid crystal display device, the light guide plate 18 made of a material such as acrylic made of a substantially rectangular shape is adhered or caulked to the upper surface 17A of the power supply side wiring substrate 16 facing the liquid crystal display element 10. A light source 20 of a backlight such as a light emitting diode or a fluorescent lamp is mounted on the side of the end face 19B opposite to the end face 19A facing the flexible wiring board 11 of the light guide plate 18. The substrate 16 is supported via a support member (not shown). Further, on the back of the light source 20, a substantially cylindrical reflecting plate 21 for preventing the light from diffusing from the light source 20 and converging in the direction of the end surface 19 </ b> B of the light guide plate 18 is provided on the power supply side wiring substrate 16. It is supported and arranged. Therefore, the light from the light source 20 travels in the light guide plate 18 toward the flexible wiring board 11.
[0010]
[Problems to be solved by the invention]
By the way, in general, the width of the flexible wiring board 11 is narrower than the width of the end face 19A of the light guide plate 17. Therefore, the light that has traveled from the light source 20 to the flexible wiring board 11 through the light guide plate 18 described above. A part of the flexible wiring board 11 is supposed to come out from both ends in the longitudinal direction of the end face 19 </ b> A of the flexible wiring board 11. For this reason, the light from the light source 20 cannot sufficiently function as a backlight of the liquid crystal display element 10, and the display on the liquid crystal display element 10 may be difficult to see.
[0011]
Therefore, conventionally, the light leakage prevention tape 22 is bonded to the end surface 19A of the light guide plate 18 to prevent light leakage. With such a configuration, the light leakage prevention tape 22 is bonded. This increases the production efficiency of the liquid crystal display device and may increase the cost of the liquid crystal display device.
[0012]
The present invention has been made in view of such problems, and by preventing light from leaking from the backlight, the light from the light source can function properly as the backlight, thereby providing a good liquid crystal display. An object of the present invention is to provide a backlight-integrated liquid crystal display device that can be realized.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the backlight-integrated liquid crystal display device according to claim 1 of the present invention is characterized in that the bent portion of the flexible wiring board protrudes from both side edges of the flexible wiring board and the longitudinal direction of the end face of the light guide plate It is in the point which provided the covering protrusion which coat | covers the both ends in.
[0014]
And by adopting such a configuration, the end face of the light guide plate can be covered by the covering protrusion formed in the width direction larger than the end face of the light guide plate, so that light is emitted from the end face of the light guide plate. Leakage to the outside of the apparatus can be prevented appropriately, and such light leakage can be prevented with a simple configuration comprising the covering projection edge.
[0015]
The backlight-integrated liquid crystal display device according to claim 2 is characterized in that, in claim 1, a white reflective layer is provided on at least a portion of the surface of the flexible wiring board facing the end face of the light guide plate. It is in.
[0016]
And by adopting such a configuration, the light reflected from the end face of the light guide plate to the flexible wiring board side is reflected to the liquid crystal display element side by the white reflective layer having a large light reflectivity, and the liquid crystal display Therefore, a clearer and better liquid crystal display can be realized by concentrating more light on the display area of the liquid crystal display element.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment of a flexible wiring board of a liquid crystal display device according to the present invention. Note that the same or corresponding components as those of the conventional one described above will be described with the same reference numerals in the drawings.
[0018]
The flexible wiring board 11A of the present embodiment is configured substantially the same as the conventional flexible wiring board 11 described above with reference to FIG. 5, and only differences from the conventional flexible wiring board 11 will be described.
[0019]
Strictly speaking, the bent portion 15 of the flexible wiring board 11A is formed with two bent portions 15A and 15B which are formed at a distance in the longitudinal direction of the flexible wiring board 11A and are actually bent slightly. The flat portion 15C formed between the two bent portions 15A and 15B.
[0020]
The flexible wiring board 11A according to the present embodiment covers the end faces 19A of the light guide plate 18 on the side edges 24A and 24B in the width direction which is the left and right direction in FIG. 1 of the bent portions 15A and 15B. The coating protrusion 23 is provided.
[0021]
As described above, the conventional flexible wiring board 11 is formed so that the entire dimension in the width direction is narrower than the width of the light guide plate 18, that is, the width of the end surface 19A. A part of the light traveling in the direction of the flexible wiring board 11 is supposed to escape from both ends of the end face 19A to the outside of the apparatus.
[0022]
On the other hand, the flexible wiring board 11A in the present embodiment is formed such that the width dimension of the portion where the covering projection edge 23 is formed is larger than the width dimension of the end face 19A of the light guide plate.
[0023]
Therefore, the end face 19A of the light guide plate 18 can be properly covered by the covering protrusion 23 up to both end portions in the longitudinal direction of the width direction, so that light can be prevented from escaping from the end face 19A to the outside of the apparatus. Can be done.
[0024]
Furthermore, since it is only necessary to form the covering projection edge 23 on the flexible wiring board 11A, the number of manufacturing steps can be reduced as compared with the case where the end face 19A of the light guide plate 18 is covered with the light leakage prevention tape 22.
[0025]
In this embodiment, in order to reuse the light leaked from the end surface 19A of the light guide plate 18 toward the flexible wiring substrate 11A for liquid crystal display, at least the end surface of the light guide plate 18 on the surface of the flexible wiring substrate 11A. A white reflective layer is provided in a portion facing 19A.
[0026]
That is, since white generally has a high light reflectance, the light reaching the end surface 19A of the light guide plate 18 can be favorably reflected to the light guide plate 18 side by making the reflective layer white.
[0027]
Therefore, since the light from the backlight can be reused for liquid crystal display, the backlight can function more effectively.
[0028]
When the surface of the flexible wiring board 11A on which the electrode circuit 13 is formed is opposed to the end surface 19A of the light guide plate 18, the resist for protecting the electrode circuit 13 is white, and this is applied to a predetermined edge of the covering projection 23. It can also serve as a reflective layer by applying up to a portion.
[0029]
Next, the operation of this embodiment will be described.
[0030]
In order to perform liquid crystal display in the present embodiment, first, when the light source 20 is turned on, the light emitted from the light source 20 is reflected to the light guide plate 18 side by the reflection plate 21, and the light guide plate 18 is entirely reflected in the light guide plate 18. It proceeds toward the flexible wiring substrate 11A while repeating the reflection.
[0031]
The light traveling in the light guide plate 18 is diffused directly or through a diffusion plate (not shown) toward the liquid crystal display element 10 located in the vicinity of the upper portion of the light guide plate 18. The display area is irradiated with plane light.
[0032]
At this time, in order to prevent a part of the light traveling in the light guide plate 18 from leaking to the electrode-side wiring board 16 side without being totally reflected, the light guide plate 18 on the side opposite to the liquid crystal display element 10 side. Is provided with a reflective layer (not shown).
[0033]
However, a part of the light traveling in the light guide plate 18 travels to the end surface 19A of the flexible wiring board 11A and tries to leak out of the light guide plate 18 from the end surface 19A.
[0034]
At this time, since the covering protrusion edge 23 whose width direction is larger than that of the end face 19A is formed on the bent portions 15A and 15B of the flexible wiring board 11A, the end face 19A has a width by the covering protrusion 23. It is in a state of being covered up to both ends in the longitudinal direction of the direction.
[0035]
For this reason, since the light which is going to come out from the end surface 19A can be shielded by the covering projection edge 23, it is possible to prevent the light from leaking outside the apparatus.
[0036]
Thereby, since the light from the light source 20 can function appropriately as a backlight, a good liquid crystal display can be performed.
[0037]
As described above, according to the present embodiment, it is possible to prevent light from leaking from both end portions of the end surface 19A of the light guide plate 18 to the outside of the apparatus by the covering projection edge 23. It can function properly as a light, and a good liquid crystal display can be performed.
[0038]
Further, since it is only necessary to form the covering projection edge 23 on the flexible wiring board 11A, it is possible to appropriately prevent light leakage of the backlight while reducing the number of manufacturing steps.
[0039]
Further, by providing a white reflective layer on at least a portion of the surface of the flexible wiring substrate 11A that faces the end surface 19A of the light guide plate 18, leakage from the end surface 19A of the light guide plate 18 to the flexible wiring substrate 11A side occurred. Since light can be reused for liquid crystal display, more light can be collected in the display area of the liquid crystal display element 10, thereby enabling clearer and better liquid crystal display.
[0040]
In addition, this invention is not limited to embodiment mentioned above, A various change is possible as needed.
[0041]
【The invention's effect】
As described above, according to the backlight integrated liquid crystal display device according to claim 1 of the present invention, the light leakage of the backlight can be appropriately prevented by the covering protrusion having a simple configuration. A good liquid crystal display can be realized while reducing the number of manufacturing steps of the display device.
[0042]
According to the backlight-integrated liquid crystal display device according to claim 2, light leaked from the end surface of the light guide plate to the flexible wiring board side can be favorably reflected to the light guide plate side by the white resist having a high reflectance. Therefore, a clearer and better liquid crystal display can be realized by condensing more light on the display area of the liquid crystal display element.
[Brief description of the drawings]
FIG. 1 is a plan view showing a flexible wiring board in an embodiment of a backlight integrated liquid crystal display device according to the present invention. FIG. 2 is a longitudinal sectional view showing an example of a general liquid crystal display element. FIG. 4 is a front view showing an outline of a liquid crystal display device. FIG. 4 is a plan view showing a conventional flexible wiring board.
1A, 1B Transparent substrate 2 Sealing material 3A Transparent common electrode 3B Transparent segment electrode 3C Lead terminal 8 Liquid crystal 9 Spacer 10 Liquid crystal display element 11, 11A Flexible wiring substrate 12 Base film 13 Electric circuit 15, 15A, 15B Curved portion 15C Plane portion 16 Electrode side wiring board 18 Light guide plate 19A, 19B End face 20 Light source 21 Reflecting plate 23 Cover protrusion 24A, 24B Both ends edge

Claims (2)

A liquid crystal display element and a power supply side wiring board at positions facing each other are connected by a flexible wiring board having a bent portion, and a light source of a backlight and light from the light source are connected to the power supply side wiring board. In a backlight-integrated liquid crystal display device equipped with a light guide plate that leads in the direction of the wiring board,
A backlight-integrated liquid crystal display, characterized in that covering bent edges projecting from both side edges of the flexible wiring board and covering both ends in the longitudinal direction of the end face of the light guide plate are provided on the bent portion of the flexible wiring board. apparatus. 2. The backlight-integrated liquid crystal display device according to claim 1, wherein a white reflective layer is provided on at least a portion of the surface of the flexible wiring board facing the end face of the light guide plate.

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