JPH08273417A - Display device - Google Patents

Abstract

PURPOSE: To provide a display device having high light utilization efficiency, a thin type, and a narrow architrave by providing plural protrusions on a surface opposite to the display panel of the light guide plate of a surface light source device, arranging the light guide plate so as to contain a thinner thickness area than the thickness of a light introduction surface, and arranging the drive circuit portion of the display panel close to the thinner thickness area. CONSTITUTION: A light guide plate 911 is arranged below a liquid panel 101, a tubular light source 951 is arranged close to a light introduction surface 921 on the side face of the light guide plate 911. Plural rows of protrusion rows 913 with triangular cross sections are arranged so as to be approximately parallel to the light introduction surface 921 on a surface opposite to the liquid crystal panel 101 of the light guide plate 911. The light guide plate 911 makes an angle θ against the light introduction surface 921 so that the thickness thereof becomes thin as parting from the tubular light source 951, and a drive circuit board 841 is arranged close to a thinner thickness portion. A display device having high light utilization efficiency, a thin type, and a narrow architrave is obtained, thereby.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device including a surface light source device such as a liquid crystal display device.

[0002]

2. Description of the Related Art A display device represented by a liquid crystal display device is
It has come to be used as various display devices for televisions, computers, car navigation systems, etc. by taking advantage of its features such as thinness, light weight, and low power consumption.

For example, a light transmission type liquid crystal display device includes a liquid crystal panel in which a liquid crystal layer is held between a pair of electrode substrates,
The liquid crystal panel includes a surface light source device that is disposed on one main surface and guides light source light to the liquid crystal panel.

In such a display device, in order to further reduce the thickness and size of the device, it is necessary to reduce the thickness of the surface light source device, so that the surface light source device of the backlight system to the edge light system is used. It's coming.

An edge light type surface light source device is, as disclosed in Japanese Utility Model Laid-Open No. 63-24529, a tubular light source and a thin plate shape such as an acrylic resin having a milky white scattering pattern printed on the back side. A light guide plate is included, and one end surface of the light guide plate is disposed in proximity to the tubular light source. Then, the light source light from the tubular light source propagates through the light guide plate, is scattered by the scattering pattern on the back surface of the light guide plate, and is emitted to the main surface of the light guide plate.

According to the above-mentioned edge light type surface light source device, although the device can be made thin, there is light loss due to the scattering pattern, and it is necessary to print the scattering pattern separately. And the improvement of productivity were respectively desired.

[0007]

As a solution to the above problems, there are known edge light type surface light source devices disclosed in, for example, JP-A-5-313163 and JP-A-6-75123. ing. This is to arrange a plurality of protrusions on the main surface side of the light guide plate facing the display panel, and to control the light emitted from the light guide plate by these protrusions. The utilization efficiency can be improved.

By the way, if the above-mentioned display device is used for a car navigation system, the external dimensions of the 1DIN standard or the like are restricted, and if it is for a personal computer, the external dimension is sufficiently set to A4 size or the like. However, in any case, it is desirable that the display screen size is sufficiently large.

From the above, the peripheral size is reduced with respect to the display screen size while maintaining the thickness of the device.
That is, it is necessary to achieve a narrower frame. The present invention has been made in view of the above technical problems, and has a high light utilization efficiency of light from a light source, and a display device in which a narrow frame can be achieved without significantly changing the thickness dimension. It is intended to be provided.

[0010]

According to a first aspect of the present invention, there is provided a display panel including a display region including a plurality of display pixels, a drive circuit section for driving the display panel, a tubular light source, and the tubular body. A light guide plate including a light introducing surface disposed near the tubular light source for introducing light source light from a light source, and the light source light propagating in the light guide plate is selectively emitted from one main surface side of the light guide plate. A display device comprising a surface light source device having a plurality of protrusions arranged on the one main surface of the light guide plate, wherein the light guide plate is thinner than a light guide plate thickness of the light introducing surface. It is characterized in that the drive circuit portion is disposed in proximity to the thin portion including a region.

According to a second aspect of the present invention, the projection according to the first aspect includes a first emission surface that emits the light source light from the tubular light source propagating in the light guide plate to the outside of the light guide plate.
It is characterized in that the light source light from the tubular light source propagating in the light guide plate has a triangular cross section including a first reflection surface that guides the light source light to the first emission surface or reflects the light into the light guide plate.

The invention described in claim 3 is characterized in that the display panel according to claim 1 and the drive circuit section are electrically connected by a flexible wiring substrate. The invention described in claim 4 is characterized in that the flexible wiring board according to claim 3 includes a drive IC. The invention described in claim 5 is characterized in that the display panel according to claim 3 is mounted with a driving IC.

[0013]

According to the display device of the present invention, the surface light source device is
As described above, the linear light source from the tubular light source is converted into the surface light source by the plurality of protrusions arranged mainly on one main surface of the light guide plate. As a result, it is possible to provide a display device with high light utilization efficiency and excellent productivity.

Further, according to the display device of the present invention, the light guide plate includes a thin region thinner than the thickness of the light guide plate on the light introducing surface,
Since the drive circuit portion is arranged close to the thin portion, the display device can be made thin and the frame can be narrowed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An active matrix type liquid crystal display device according to an embodiment of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, the liquid crystal display device (1) of this embodiment includes a light-transmissive liquid crystal panel (101) that operates in a normally white mode, and one side of the liquid crystal panel (101). Four signal line driving ICs (801), (802), (803), (804) that carry serial-parallel conversion of serial image data into parallel image data and output as analog image data that is mounted, liquid crystal panel ( 101) Two scanning line driving ICs (821), (822) mounted along one end of the other and outputting sequential scanning pulses
4 signal line driving ICs (801), (802), (803), (804)
The drive circuit board arranged on the back side of the liquid crystal panel (101) for outputting the serial image data and the control signal to the IC and outputting the start signal and the control signal to the two scanning line driving ICs (821) and (822). (841) (see FIG. 2), drive circuit board (841) and signal line drive ICs (801), (802), (803), (804)
Flexible wiring board (FPC) (8
11), driving circuit board (841) and two scanning line driving ICs (8
A flexible wiring board (FPC) (831) for connecting to 21) and (822), and a surface light source device (901) arranged on the back surface side of the liquid crystal panel (101) are included.

Further, as shown in FIG. 2, the surface light source device (90
1) is held by a resin frame (115), and the drive circuit board (841) is also attached to the back side of the surface light source device (901) by the frame (1
Retained by 15). In addition, a metal bezel with an opening exposing this frame (115) and display area (103).
The liquid crystal panel (101) is sandwiched by (111).

The liquid crystal panel (101) comprises a display area (103) having a diagonal of 14 inches as shown in FIG. More specifically, as shown in FIG. 4, the array substrate (200) and the counter substrate (300) are arranged with a gap of 5 μm interposed therebetween with a sealant (not shown), and the gap is orthogonal to each other. A liquid crystal layer (401) mainly composed of a nematic liquid crystal material having a positive dielectric anisotropy is formed through the alignment films (291) and (391) that are rubbed in the direction of It is held.

As shown in FIGS. 3 to 4, the array substrate (200) has a plurality of scanning lines Yj (j = 1, 2, ..., N) and a plurality of scanning lines on one main surface side of the glass substrate (201). Signal line Xi (i = 1,2, ...,
m) are arranged in a matrix and ITO (Indium-Tin-Oxi) is formed in a region surrounded by the scanning lines Yj and the signal lines Xi.
A transparent pixel electrode (251) composed of de) is arranged.
A thin film transistor (hereinafter abbreviated as TFT) (231) is arranged near each intersection of the scanning line Yj and the signal line Xi. This TFT (231) uses the scanning line Yj itself as a gate electrode (211), an insulating film (213) arranged on the gate electrode (211), and an island-shaped amorphous silicon arranged via the insulating film. (A-Si: H) thin film (215), a-Si: H thin film
(215) Channel protective film (217), aS placed on top
A drain electrode (221) extending from the signal line Xi and electrically connected to the i: H thin film (215), a pixel electrode (251) and a-
A source electrode (2) for electrically connecting to the Si: H thin film (215)
23) and Further, between the drain electrode (221) and the source electrode (223) and the a-Si: H thin film (217),
In order to obtain a good ohmic junction, n ⁺ type a-Si: H thin films (222) and (224) containing phosphorus as impurities are arranged as low resistance semiconductor films.

Further, an auxiliary capacitance line Cj made of the same material as the scanning line Yj and wired substantially parallel to the scanning line Yj is arranged on the glass substrate (201), and has a pixel electrode (251) and an auxiliary capacitance line Cj. The auxiliary capacitance (Cs) is formed by.

The counter substrate (300) is formed on the glass substrate (301) facing the array substrate (200) and the TF of the array substrate (200).
T (231), between the light-shielding film (311) and the light-shielding film (311) arranged so as to shield the gap between the signal line Xi and the pixel electrode (251) and the gap between the scanning line Yj and the pixel electrode (251). A color filter layer (321) composed of red (R), green (G), and blue (B) color portions, and a counter electrode (331) composed of ITO disposed on the color filter layer (321). Including.

The array substrate (200) and the counter substrate (3
Polarizing plates (411) and (421) are attached to the outer surface of (00), respectively, and thus the liquid crystal panel (101) having a plurality of display pixels is constructed.

Next, the surface light source device (901) will be described. As shown in FIG. 2, the surface light source device (901) is a molded body made of acrylic resin and has a substantially rectangular light guide plate (911) which is slightly larger than the effective display area (103) of the liquid crystal panel (101). ), A tubular light source (951) that is arranged in close proximity with one end surface of the light guide plate (911) as a light introduction surface (921), and a reflective film (guide film that efficiently guides the light source light from the tubular light source (951) to the light guide plate (911). 9
61) includes a prism sheet (991) disposed between the light guide plate (911) and the liquid crystal panel (101).

The light guide plate (911) is constructed so that the thickness thereof continuously decreases as the distance from the light introduction surface (921) increases. More specifically, the angle (θ) formed by the main surface on the back side of the light guide plate (911) with respect to the perpendicular of the light introduction surface (921) is approximately 0.5.
It is set to ゜.

Then, on the main surface of the light guide plate (911),
A projection array (913) having a triangular cross section is provided on the light introducing surface (921) so that the light source light introduced from the light introducing surface (921) is selectively prevented and the spread of the light source light emitted from the light guide plate (911) is suppressed. ) Are arranged in parallel with each other. This row of protrusions (913)
Are arranged alternately in a plane, and are arranged so that the arrangement pitch becomes denser as the distance from the tubular light source (951) increases. In addition, as shown in FIG. 4, each of the projection rows (913) has a reflection surface (913a) on the light introduction surface (921) side and a light guide plate.
The exit surface (913b) is included on the edge side of (911).

By the way, since the light guide plate (911) is made of acrylic resin, the light source light of the tubular light source (951) incident from the light introduction plane (921) is perpendicular to the light introduction plane (921). The light is incident on the light guide plate (911) with a condensing angle (Ω1) of about 42 °.

From the above, the angle (θ) formed by the reflecting surface (913a) of the projection row (913) with respect to the perpendicular of the light introducing surface (921)
1) is set to 40 °, and the exit surface (9) of the projection row (913) is
The angle (θ2) formed by 13b) and (915b) is set to about 90 °. Here, the angle (θ1) is set to 40 °, but the angle (θ1) is not limited to this, and the light source light incident from the light introduction surface (921) is generally projected.
What is necessary is that it is set so as to be guided to the exit surface (913b). However, if the angle (θ1) is too small, it becomes impossible to arrange a large number of the projection rows (913), which may lead to uneven brightness. Therefore, it is preferable to set the angle within the range of 20 to 40 °.

Particularly, as in this embodiment, since the main surface on the back side of the light guide plate (911) is formed with a predetermined angle (θ) with the light introducing surface (921), the angle (θ1) is set. It is possible to set a large value, whereby the array pitch of the protrusion rows (913) can be set to a small value, and thus in-plane variations in brightness can be reduced.

Although the angle (θ2) is set to about 90 ° here, it is preferably 80 ° or more in order to reduce the spread of the emitted light, and may be an obtuse angle exceeding 90 °. With such a configuration, the emission surface of the protrusion array (913)
From (913b), the light source light condensed at a spread angle (Ω2) of about 90 ° is emitted toward one end of the light guide plate (911).

The prism sheet (991) arranged between the liquid crystal panel (101) and the light guide plate (911) protrudes toward the light guide plate (911) side, and the projection row (913) of the light guide plate (911). And a plurality of protrusion rows (993) arranged substantially parallel to each other. These protrusion rows
(993) transmits the light emitted from the light guide plate (991) to the liquid crystal panel (10
1) Including a refracting surface (993a) that guides to the side, prism sheet (991)
The angle (θ3) between the main surface of the and the refracting surface (993a) is about 3
It is set to 0 °.

Thus, the light source light emitted toward the end side of the light guide plate (911) is controlled to be the surface light source light toward the liquid crystal panel (101) side. With the above configuration, the liquid crystal display device (1) operates as follows.

The light source light incident from the tubular light source (951) to the light introduction surface (921) of the light guide plate (911) propagates inside the light guide plate (911), and a part of the light is emitted from the projection row (913). It is emitted from the surface (913b). Then, the emitted light emitted from the light guide plate (911) is
It is controlled by the prism sheet (991) to be uniform surface light source light condensed toward the liquid crystal panel (101).

As described above, according to the liquid crystal display device of this embodiment, the light source light emitted from the light guide plate toward the liquid crystal panel is integrally formed with the light guide plate on one main surface of the light guide plate. Since it is converted into the surface light source light directed to the liquid crystal panel side by the projection row, the light utilization efficiency of the light source light is high, and thereby high contrast can be achieved. The power consumption of the tubular light source can be reduced as long as the contrast is of a conventional level. Further, since such a light guide plate can be integrally molded, the cost of the device can be reduced.

Furthermore, in this embodiment, since the main surface on the back side of the light guide plate is continuously thinly formed at a predetermined angle with the light introducing surface of the light guide plate, the projection row pitch should be set small. Therefore, the in-plane luminance variation can be sufficiently suppressed.

Further, in this embodiment, the back side of the light guide plate,
In particular, since the drive circuit board is housed in the thin portion of the light guide plate, a narrow frame can be achieved without impairing the thickness dimension of the liquid crystal display device.

In this embodiment, no treatment is applied to the back surface side of the light guide plate, but for example, projections or grooves are arranged so that part of the light source light propagating in the light guide plate is emitted from one main surface side. By controlling so that the in-plane luminance variation is further reduced.

By the way, in this embodiment, the light guide plate made of acrylic resin is used, but other materials may be used. In this case, since the solid angle of the light source light incident from the light introduction surface is slightly different, the angle formed by each projection row may be appropriately changed in consideration of the above-mentioned circumstances.

Further, in this embodiment, the light source light emitted from the surface light source device is controlled to have a small converging angle. Therefore, if a scattering film or the like is arranged on the observer side of the liquid crystal panel, The viewing angle can be improved, which is suitable for displaying to viewers at various angles.

Further, in this embodiment, the signal line is drawn out only to one end side of the array substrate and the scanning line is drawn out only to the other end side, and further, the driving IC is mounted on the array substrate, and the array substrate and Although the drive circuit board is electrically connected by the FPC to achieve a narrow frame, the drive circuit board and the array board are formed by a TAB-IC or the like in which the drive IC is mounted on the flexible wiring board and the array board and the drive circuit. It may be electrically connected to the substrate. Also,
In this embodiment, one end surface of the light guide plate is the light introduction surface,
A tubular light source may be arranged by providing a groove or a through hole including a light introduction surface in the light guide plate.

[0039]

According to the display device of the present invention, since the surface light source device having high light utilization efficiency of the light source light and excellent in productivity is provided, the display device can be manufactured at low cost, and the contrast can be improved. Low power consumption can be achieved. Further, according to the present invention, it is possible to achieve a narrow frame without significantly changing the thickness dimension.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of the display device taken along the line AA ′ in FIG.

FIG. 3 is a partial schematic front view of an array substrate of a liquid crystal display device according to an embodiment of the present invention.

FIG. 4 is a partial schematic cross-sectional perspective view of a liquid crystal display device according to an embodiment of the present invention.

[Explanation of symbols]

 (1) ... Liquid crystal display device (100) ... Array substrate (300) ... Counter substrate (901) ... Surface light source device (913) ... Projection row (913a) ... Reflection surface (913b) ... Emission surface (951) ... Tubular light source

Claims (5)

[Claims] 1. A display panel including a display region composed of a plurality of display pixels, a drive circuit section for driving the display panel, a tubular light source, and an arrangement arranged in proximity to the tubular light source for introducing light source light from the tubular light source. Arranged on the one main surface of the light guide plate that selectively emits the light source light propagating in the light guide plate from one main surface side of the light guide plate. And a surface light source device including a protrusion, wherein the light guide plate includes a thin region thinner than the thickness of the light guide plate of the light introduction face, and the drive circuit unit is close to the thin unit. A display device characterized by being arranged in a row. 2. The projection according to claim 1, wherein the projection has a first emission surface that emits the light source light from the tubular light source that propagates in the light guide plate to the outside of the light guide plate, and the protrusion that propagates in the light guide plate. A display device having a triangular cross section including a first reflection surface that guides the light source light from a tubular light source to the first emission surface or reflects into the light guide plate. 3. The display device according to claim 1, wherein the display panel and the drive circuit section are electrically connected by a flexible wiring board. 4. A display device, wherein the flexible wiring board according to claim 3 includes a drive IC. 5. The display panel according to claim 3 is a driving IC
A display device characterized by being equipped with.