JP3080664B2 - Liquid crystal display - Google Patents

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 for guiding light from a linear light source to a liquid crystal display panel through a light guide plate and a reflection plate.

[0002]

2. Description of the Related Art In a transmissive or transflective liquid crystal display device used for a display device such as a word processor or a personal computer, an illumination is usually arranged on the back of a liquid crystal display panel. The illumination includes a light source such as a fluorescent lamp and a cold cathode discharge tube placed directly below the liquid crystal display panel, and a light source using a light guide plate to guide light from the light source to the liquid crystal display panel. A device using a light guide plate is generally called a side light system, in which a light source such as a cold cathode discharge tube having a diameter of about 5 to 10 mm is placed in a lateral direction of the liquid crystal display panel, and a thick plate is provided directly below the liquid crystal display panel. Since only a light guide plate made of acrylic or the like having a thickness of about 2 to 4 mm is merely provided, the entire liquid crystal display device can be made thinner, and a brighter illumination can be obtained as compared with a device utilizing EL (electroluminescence). .

Here, a conventional liquid crystal display device using this type of sidelight system is disclosed in, for example,
A configuration described in Japanese Patent No. 62105 is known.

Japanese Patent Application Laid-Open No. 63-62105 discloses that
The light-introducing end of the light guide plate is arranged adjacent to the linear light source, a curved reflector is opposed to the linear light source, and a flat plate reflector is opposed to one side of the light guide plate. A liquid crystal display panel is arranged on the other surface of the light guide plate on the opposite side of the above. The light from the linear light source is guided by a curved reflecting plate, a flat reflecting plate, and a light guide plate to illuminate the liquid crystal display panel from behind.

[0005]

However, in the configuration described in Japanese Patent Application Laid-Open No. 63-62105, a curved reflecting plate corresponding to a linear light source and a flat reflecting plate corresponding to a light guide plate are separately provided. However, there is a problem that the configuration is complicated and the display quality may be deteriorated.

The present invention has been made in view of the above problems, and has as its object to provide a liquid crystal display device having a simple structure and improved display quality.

[0007]

The present invention provides a linear light source,
Inclusion and the light input end has a light introducing end the linear light source disposed proximate to the light guide plate, flat plate portion disposed to face the light guide plate, the linear light source at one end bends and we provided in the bend portion formed integrally with said plate and
A reflecting plate formed of a resin film having at least one slit formed thereon, and a first substrate and a second substrate each having an electrode formed on one main surface thereof, wherein the first substrate And a second substrate with one main surface facing each other, a liquid crystal sandwiched in a gap between the first substrate and the second substrate, and the light guide plate on the other main surface of the first substrate. And a liquid crystal display panel which is opposed to the flat plate portion and has light from the linear light source guided by the light guide plate and the reflection plate.

Further, slits are those formed substantially orthogonal to the longitudinal direction of the linear light source.

[0009] is et al., Reflector, in which the tip of the bent portion is fixed to the vicinity of the light introducing end portion of the light guide plate.

[0010]

According to the present invention, the linear light source is included, the light from the linear light source is bent, and a reflecting plate formed of a resin film having a flat portion integrated with the bent portion is used. in Do arrangement, Ki de be guided to the liquid crystal display panel by the reflecting plate light guide plate and the light from the linear light source, or, providing at least one slit in the bent portion enclosing the linear light source reflector Thereby, distortion generated between the flat portion and the bent portion of the reflection plate is escaped, wrinkles are prevented from being generated in the flat plate portion, and light guided by the reflection plate and the light guide plate is not uneven, and display quality is improved. Is improved.

[0011] The slit because it is formed substantially orthogonal to the longitudinal direction of the linear light source, the distortion can be absorbed efficiently, thereby improving the hardly display quality occurs unevenness.

[0012] is et al., The reflection plate is mounted while maintaining because it is fixed in the vicinity of the light introducing end of the tip is the light guide plate bend, the reflector also bend of the resin film, uneven Is less likely to occur and display quality is improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the liquid crystal display device of the present invention will be described below with reference to a liquid crystal display device using a sidelight system shown in FIG.

FIG. 1 is a schematic diagram showing one embodiment of a liquid crystal display device.
In the side view, as shown in FIG. 1, for example, the cold cathode discharge tube 1 for example as a linear light source of the cold cathode discharge tube, adjacent the rectangular light input end 2a of the light guide plate 2 of the acrylic plate Have been placed. The surface of the light guide plate 2 opposite to the liquid crystal display plate 3 is provided with a milky white print (not shown), and the density, that is, the reflectance of the milky white print changes from one end to the other end. Reference numeral 5 denotes a reflection plate made of a resin film having high reflectivity such as polyester. The reflection plate 5 has a curved portion as a curved portion whose one end side is curved so as to surround the light source 1.
At 5a, a flat plate portion 5b is fixed on the light guide plate 2 by the pressing plate 6, and the other end is a flat plate portion 5b facing the back surface of the light guide plate 2.

[0015] Then, to assist the lordosis curved portion 5a that guides the light input end 2a of the light guide plate 2 the light from the light source 1, a liquid crystal display light flat portion 5b is scattered by milky printing of the light guide plate 2 Board 3
Lead to.

The resin film of this type has a higher reflectivity and is thinner than a metal such as aluminum, so that the display can be made with a simple structure by using the resin film reflecting plate 5. A light-weight liquid crystal display device having a bright, thin outer shape and light weight can be constructed.

Next, another embodiment will be described with reference to FIGS.

FIG. 2 is a schematic plan view of another embodiment viewed from the display surface side, FIG. 3 is a schematic cross-sectional view of the AA 'plane of FIG. 2 viewed from the direction of the arrow, and FIG. FIG. 2 is a schematic bottom view when a reflection plate is viewed from a side opposite to a liquid crystal display panel in FIG.

2 and 3, reference numeral 11 denotes a liquid crystal display panel. As shown in FIG. 3, the liquid crystal display panel 11 is formed on one main surface of a first substrate 12 and a second substrate 13 made of glass, for example. Are electrodes 14, 15 of ITO (Indium Tin Oxide), respectively.
Are formed, and light distribution films 16 and 17 made of, for example, polyimide are formed so as to cover the electrodes 14 and 15.

Then, the first substrate 12 and the second substrate 13
For example, a thermosetting epoxy resin adhesive 18 is printed on one main surface of the first substrate 12 which is one of them, in a frame shape having a portion to be a liquid crystal injection opening. A spherical spacer 19 made of resin is dispersed on one main surface of the second substrate 13 which is the other of the substrate 12 and the second substrate 13. Subsequently, the first substrate 12 is placed so that one main surface side faces each other.
After the combination of the first substrate 12 and the second substrate 13, the liquid crystal 20 is injected from the liquid crystal injection port.
The liquid crystal 20 is held in the gap between the substrates 13. Then, a predetermined liquid crystal display panel 11 is obtained by sealing the liquid crystal injection port.

Subsequently, the first substrate 12 and the second substrate 13
Polarizing plates 21 and 22 are attached to the other main surface side between them.

On the other main surface side of the first substrate 12, a liquid crystal drive circuit board 26 is disposed. The liquid crystal drive circuit board 26 and the liquid crystal display panel 11 are connected to connection means 27 such as a flexible cable. Are electrically connected to each other.

The liquid crystal display panel 11 and the liquid crystal drive circuit board
A light guide plate 31 made of, for example, an acrylic plate is disposed between the light guide plate 26 and the light guide plate 31. Tubular light source
32 are provided. On the surface of the light guide plate 31 opposite to the liquid crystal display panel 11, a reflection pattern 33 is formed by, for example, milky white printing.

Between the light guide plate 31 and the liquid crystal drive circuit board 26, a film-like reflecting plate 36 made of, for example, polyester resin is provided. This reflecting plate 36 is
The portion opposed to the liquid crystal display panel 11 with the interposition therebetween, in particular, the portion overlapping with the liquid crystal display plate 11 is a flat plate portion 36b.
One end of the reflection plate 36 is a curved portion 36a as a curved portion including the tubular light source 32, and the tip of the curved portion 36a is fixed on the light guide plate 31 in the vicinity of the light introducing end 31a. Have been.

The curved portion 36a of the reflector 36 has a tubular light source 3
Three slits 37 having a direction substantially perpendicular to the central axis are provided at equal intervals. These slits
As shown in FIG. 4, 37 has a length that does not reach the flat plate portion 36b of the reflection plate 36, particularly a region that greatly affects display and overlaps the liquid crystal display panel 11.

In use, light from the tubular light source 32 is guided to the liquid crystal display panel 11 by the light guide plate 31 and the reflection plate 36, and the liquid crystal display panel 11 is illuminated from the back. At this time, the curved portion 36a of the reflector 36 including the tubular light source 32 is
The light from the tubular light source 32 is guided to the light introduction end 31a of the light guide plate 31, and the flat plate portion 36b of the reflection plate 36 is connected to the light guide plate 31.
To guide the light scattered by the reflection pattern 33 to the liquid crystal display panel 11.

When the reflector 36 is manufactured, the slit 37 is used.
After the formation, the curved portion 36a is formed by heating. At this time, the three slits 37 in the curved portion 36a allow the distortion caused by the difference in the amount of contraction generated between the flat plate portion 36b and the curved portion 36a of the reflector 36 to escape, and FIG. Unlike the case shown, wrinkles 7 do not occur on the flat plate portion 5b,
The flatness of 36b is improved.

Here, in general, uniformity of illumination from the back is very important, and a decrease in uniformity directly leads to a decrease in display quality. In particular, local unevenness makes display very difficult to see. Since the flatness of the flat plate portion 36b of the reflection plate 36 is improved, uniform backlighting can be obtained without unevenness in illumination from the backside during use. Since the slit 37 is located at the curved portion 36a, the illumination does not become uneven. Therefore, display quality is improved.

Further, since the reflection plate 36 is made of a resin film instead of a metal such as aluminum, a bright display can be performed, and the entire liquid crystal display device can be reduced in weight and thickness. In addition, this type of resin film has poor moldability at room temperature and needs to be heated when forming the curved portion 36a. During this heat forming, the resin film shrinks, but the flat portion 36a Even if heat is applied only to the curved portion 36a to maintain flatness and a partial difference occurs in the amount of shrinkage, it is possible to prevent distortion from occurring at a portion where the curved portion 36a and the flat plate portion 36b are in contact.

Further, since the curved portion 36a and the flat plate portion 36b are cut into each other to form two members, and it is not necessary to join the curved portion 36a and the flat plate portion 36b after the curved portion 36a is formed by heating, the curved portion 36a and the flat plate portion 36b are not required. Light can be scattered at the junction with the portion 36b to cause uneven illumination light, and processing costs can be prevented from increasing due to an increase in the number of manufacturing steps.

As described above, according to the configurations shown in FIGS. 2 to 4, it is possible to provide a lightweight and thin liquid crystal display device having high display quality and capable of performing bright display.

Further, since the distortion at the time of forming the reflector 36 occurs in the direction of the central axis of the tubular light source 32, the direction of the slit 37 is made substantially perpendicular to the direction of the central axis of the tubular light source 32. In addition, a greater effect can be obtained in eliminating distortion during heat molding.

However, even if the angle formed by the slit with respect to the central axis of the tubular light source is about 45 °, almost the same effect can be obtained by increasing the number of slits.

In the embodiment shown in FIGS. 2 to 4,
The curved portion 36a of the reflecting plate 36 is shaped into a curved surface. However, as shown in FIG.
Even when the bent portion is a bent portion 41a bent into a prismatic shape, the same phenomenon occurs when heating during processing, which is effective. In FIG. 6, reference numeral 41b denotes a flat plate portion of the reflection plate 41.

[0035]

According to the present invention, a reflecting plate formed of a resin film having a curved portion and a flat portion integrated with the curved portion is used to enclose the linear light source and emit light from the linear light source. it allows a simple configuration, Ki the light from the linear light source out to lead to the liquid crystal panel by the light guide plate and the reflection plate, was or,
By providing at least one slit in the bent portion including the linear light source of the reflector, distortion generated between the flat portion and the bent portion of the reflector is escaped, and no wrinkles are generated in the flat portion, The display quality can be improved without unevenness of the light guided by the reflection plate and the light guide plate .

[Brief description of the drawings]

FIG. 1 is a schematic side view showing one embodiment of a liquid crystal display device of the present invention.

FIG. 2 is a schematic plan view showing a liquid crystal display device of another embodiment of the same as viewed from the display surface side.

FIG. 3 is a schematic cross-sectional view when the AA ′ plane of FIG. 2 is viewed from the direction of the arrow.

FIG. 4 is a schematic bottom view when the reflector is viewed from the side opposite to the liquid crystal display panel in FIG. 2;

FIG. 5 is a schematic bottom view showing a problem of the liquid crystal display device shown in FIG. 1;

FIG. 6 is a schematic sectional view showing a liquid crystal display device according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cold cathode discharge tube as a linear light source 2, 31 Light guide plate 3, 11 Liquid crystal display panel 5, 36, 41 Reflector plate 5a, 36a Curved portion 5b, 36b, 41b as a curved portion Flat plate portion 12 First substrate 13 Second substrate 14, 15 electrode 20 liquid crystal 31a light introducing end 32 tubular light source as linear light source 37 slit 41a bent portion as bent portion

Claims (3)

(57) [Claims] 1. A linear light source, a light guide plate having a light introducing end at one end, and the light introducing end disposed close to the linear light source; and a light guide plate disposed opposite to the light guide plate. Flat portion , a bent portion including the linear light source and integrally formed with the flat portion and
A reflector formed of a resin film having at least one slit provided in the bent portion ; a first substrate and a second substrate each having an electrode formed on one principal surface thereof; The first substrate and the second substrate face each other on one principal surface side, and a liquid crystal is sandwiched in a gap between the first substrate and the second substrate. A liquid crystal display panel facing the flat plate portion with the light guide plate interposed therebetween, and light from the linear light source guided by the light guide plate and the reflection plate. 2. A slit, a liquid crystal display device according to claim 1, characterized in that formed substantially orthogonal to the longitudinal direction of the linear light source. 3. A reflector according to claim 1, characterized in that the tip of the bent portion is fixed to the vicinity of the light introducing end portion of the light guide plate or
3. The liquid crystal display device according to item 2 .