JP2000284282A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction which dispenses with a sticking operation of a reflection film to guide light to a light transmission plate in the case a liquid crystal panel and a panel supporting body are present and to provide a construction of a liquid crystal display device to prevent light other than the light normally emitted from the light transmission plate from leaking. SOLUTION: Inside a frame of a supporting frame 41, a pair of expanded frame part 41d which is formed so as to protrude from left and right respectively as shown in the figure is formed between a rear side housing part 41a to hold a light transmission plate 42 and a front side housing part 41b to hold a liquid crystal panel 10. An inclined surface part 41f obliquely opposed to an outside end face 42c of the light transmission plate 42 is formed on the rear side of the expanded frame part 41d. The supporting frame 41 is formed with a white resin and its surface part 41f functions as a light reflection surface to guide light inside the light transmission plate 42.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display device, and more particularly to a structure of a liquid crystal display device having a liquid crystal panel and a panel support having a light guiding function for irradiating the liquid crystal panel with light. .

[0002]

2. Description of the Related Art A liquid crystal display device comprises a liquid crystal panel in which liquid crystal is sealed between a pair of substrates, and a panel support for supporting the liquid crystal panel for mounting the liquid crystal panel in various devices. There are things.

As a liquid crystal display device having the above-described structure, and particularly configured to be installed on a circuit board inside a portable device, there is a liquid crystal display device having a structure shown in FIGS. 5 and 6, for example. In this liquid crystal display device, a pair of substrates 11 and 12 are bonded via a sealing material (not shown), a liquid crystal is sealed between the substrates surrounded by the sealing material, and polarizing films 13 and 14 are formed on the outer surfaces of the substrates 11 and 12. It is composed of a liquid crystal panel 10 attached and a panel support 20 for accommodating the liquid crystal panel 10. The panel support 20 includes a support frame 21 integrally formed of a synthetic resin and the support frame 2.
1 and a flat light guide plate 22 made of a transparent resin.

The light guide plate 22 is accommodated in a back side accommodating portion 21a on the back side of the support frame 21, and is supported by a contact supporting portion 21c. A reflection film 23 made of a white resin sheet or the like is adhered on the back surface of the light guide plate 22 (the surface opposite to the side where the liquid crystal panel is arranged). The outer end surface 22a of the light guide plate 22 is an inclined surface obliquely facing the front side,
A belt-like reflective film 24 is adhered to the outer end face 22a.

On the other hand, a front side housing 21b is formed on the front side of the support frame 21, and the liquid crystal panel 10 is housed in the front side housing 21b and fixed by a double-sided adhesive tape (not shown) or the like. At this time, the liquid crystal panel 10 is arranged parallel to the front side of the light guide plate 22.

In this example, a light source 30 such as an LED (light emitting diode) is mounted on a circuit board (not shown). When the panel support 20 is fixedly mounted on the circuit board, as shown in FIG. The reference numeral 30 is arranged on the inner peripheral portion of the back side housing portion 21 a of the support frame 21. Light source 3
0 irradiates light to the periphery of the light guide plate 22, and the light is introduced into the light guide plate 22 from the back surface 22 b not covered with the reflection film 23 through the optical opening 20 a, The light is reflected by the reflection film 24 adhered to the end face 22a and is introduced toward the plate surface of the light guide plate 22 (inside the light guide plate). The light thus introduced is emitted from the front surface to the liquid crystal panel 10 almost uniformly by the internal structure of the light guide plate 22 and the action of the reflection film 23. This light passes through the liquid crystal panel 10 and enters the eyes of a viewer who views the display surface.

[0007]

By the way, with the recent miniaturization of portable devices, for example, cellular phones, liquid crystal display devices incorporated in portable devices have been required to be smaller and thinner. In this case, if it is attempted to reduce the size of the liquid crystal display device without reducing the effective display region 10V of the liquid crystal display device having the structure shown in FIG. It is necessary to reduce the existing outer region (frame region) 10E and the peripheral region 20E of the panel support 20.
However, the width of the outer end surface 22a of the light guide plate 22 must be reduced in order to form the peripheral region 20E of the panel support 20 with a small width, so that the reflection film 24 adhered thereto also has a small width. In addition, there is a problem that complicated pasting work conventionally performed manually becomes more difficult.

Further, in the conventional structure shown in FIG. 6, light incident from the back side of the liquid crystal panel 10 is guided into the light guide plate 22 by the reflection film 24 adhered on the outer end face 22a. As a result, the reflection film 24
The leakage light 30a leaks to the front side from the gap between the liquid crystal panel and the support frame 21, so that there is a problem that the light leakage is visually recognized at the periphery of the liquid crystal panel. In particular, if the sticking position of the reflective film 24 shifts, the light leakage becomes extremely large, which reduces the brightness of the effective display area 10V and deteriorates the visibility.

Accordingly, the present invention is to solve the above-mentioned problem, and an object of the present invention is to attach a reflective film for guiding light to a light guide plate in a liquid crystal display device having a liquid crystal panel and a panel support. It is an object of the present invention to provide a novel liquid crystal display device that can provide a structure that can be made unnecessary and that can prevent leakage of light other than that normally emitted from a light guide plate.

[0010]

According to another aspect of the present invention, there is provided a liquid crystal display device comprising a liquid crystal panel and a panel support for supporting the liquid crystal panel. A light guide part having a light guide surface for illuminating the liquid crystal panel by emitting light introduced from the light guide surface and illuminating the liquid crystal panel, comprising: a light guide surface; And a support frame portion formed of a conductive material, wherein the support frame portion is disposed at a position facing or closely contacting the light introduction surface, and a surface portion that reflects incident light toward the light introduction surface side. It is characterized by being provided.

According to the present invention, since the surface portion for reflecting the incident light toward the light introducing surface is integrally formed on the support frame portion of the panel support, a belt-shaped reflective film is adhered as in the related art. Since the necessity is eliminated, assembling work is facilitated, and light leakage from between the adhered reflective film and the panel support can be prevented.

In the present invention, it is preferable that the panel support is provided with an optical opening through which light is incident on the surface portion.

According to the present invention, an optical opening is provided in the panel support, and light is allowed to enter from the optical opening toward the surface portion. Since the liquid crystal panel can be illuminated by arranging it so as to face the optical opening, either when the light source is mounted in the panel support or when the light source is mounted on another member, for example, on a circuit board. Can also respond.

In each of the above inventions, the support frame portion is formed in a frame shape so as to surround the light guide portion, and the light guide portion is a light guide plate housed in the support frame portion, and Is preferably the outer end face of the light guide plate.

According to the present invention, the surface portion is formed on the frame-shaped support frame portion, and the outer end surface of the light guide plate housed in the support frame portion is configured as the light introduction surface, so that the panel support has a simple structure. It can be.

In each of the above inventions, the light guide portion is a light guide plate disposed substantially parallel to a panel surface of the liquid crystal panel so that the light emission surface faces the liquid crystal panel. An end surface substantially orthogonal to a panel surface, wherein the front surface portion reflects the incident light incident from the rear surface side of the liquid crystal panel toward the light introduction surface side and introduces the light into the light guide portion. It is preferable that both the light-incident surface and the light-introducing surface are inclined.

According to the present invention, it is possible to block incident light incident from the rear side and prevent the light from leaking to the front side only by providing a surface portion serving as a light reflecting surface on the support frame portion.

In the above invention, the light-reflective material preferably has a white color.

According to the present invention, since the surface portion is constituted by a white surface, it is possible to form white scattered light which is preferable as a backlight or other illumination light of a liquid crystal panel.

In each of the above inventions, when light is incident on the surface from a light source provided in the liquid crystal display device or a light source provided separately from the liquid crystal display device, the light is emitted on the surface portion. The light is reflected and the light is introduced into the light guide. Here, the configuration of the liquid crystal display device includes a case where incident light is once introduced into the light guide portion, then goes to the surface portion, is reflected by the surface portion, and is again introduced into the light guide portion.

[0021]

Next, an embodiment of a liquid crystal display device according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view of the present embodiment, and FIG. 2 is a plan view of a panel support of the present embodiment. In the present embodiment,
Support frame 41 made of white polycarbonate resin or the like
The liquid crystal panel 10 is supported by a panel support 40 having a light guide plate 42 made of transparent polycarbonate, acrylic resin, or the like. Since the liquid crystal panel 10 is not different from the above-mentioned conventional one, the same parts are denoted by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 2, the support frame 41 constituting the panel support 40 is formed in a rectangular frame shape in plan view, and the light guide plate 42 is accommodated in the frame. The light guide plate 42 is provided as shown in FIG.
From above, is fitted into the central portion of the support frame 41 (inside of the frame shape), and is brought into contact with and supported by the contact support portion 41c projecting into the frame on the back side of the support frame 41. Light guide plate 4
A liquid crystal panel 10 has a white reflective film 43 made of PET (polyethylene terephthalate) resin or the like in advance.
Is affixed to the surface opposite to the side on which is disposed.

Inside the support frame 41, a rear housing portion (housing space) 41a configured to house the light guide plate 42 on the rear side thereof and the liquid crystal panel 10 to be housed on the front side thereof. , A front housing portion 41b (housing space) for supporting the end surface (outer peripheral portion) of the liquid crystal panel 10 in a frame shape, and a frame from the front housing portion 41b for supporting the end portion of the liquid crystal panel 10 from behind. A pair of overhanging frame portions 41d are formed so as to overhang inside. The upper surface of each overhang frame portion 41d shown in FIG. 1 is configured as a flat panel support surface 41e that supports the liquid crystal panel 10.
The lower surface (rear surface) shown in FIG. 1 of the overhang frame portion 41d is formed with an inclined surface portion 41f obliquely opposed to the outer end surface 42c of the light guide plate 42. That is, the overhang frame portion 4 of the support frame
An inclined surface portion 41f is formed between 1d and the rear housing portion 41a (behind the surface of the overhanging frame portion 41d supporting the end of the liquid crystal panel 10). This surface portion 41f is
Since the support frame 41 of the panel support 40 is formed of a white resin, it functions as a light reflection surface. The surface portion 41f is provided with a light source 30 such as an LED (light emitting diode) mounted on a circuit board (not shown).
And the direction in which light emitted from the light source 30 is incident so that the light can be directed to the outer end surface 42c of the light guide plate 42 disposed on the side of the surface portion 41f. 42 are formed so as to obliquely face both directions in which the outer end surfaces 42c of the 42 are arranged.

In this embodiment, the light source 30 is mounted on a circuit board (not shown), and the light source 30 is mounted inside the support frame 41 of the panel support 40 by installing the panel support 40 on the circuit board. There, the back side storage part 41a
It is arranged so that it may fit in the inner peripheral part. The support frame 41 is provided with a light introducing portion 40a that opens the surface portion 41f toward the light source 30. Alternatively, the light source 30 is provided in the light introduction (opening) portion 40a of the panel support 40 so as to be attached to the panel support 40 itself.
May be electrically connected to the outside to supply power to the light source.

FIG. 3 is an enlarged sectional view showing a main part of this embodiment in an enlarged manner. In this embodiment, the light emitted (emitted) from the light source 30 passes through the optical opening 40a opened in the peripheral portion of the back side housing portion 41a and passes through the support frame 41.
The light is reflected by the surface portion 41f and is introduced (incident) into the light guide plate 42 from the outer end surface 42c. The light introduced into the light guide plate 42 is
The liquid crystal is reflected on the front side (the side on which the liquid crystal panel 10 is disposed) by the reflection film 43 adhered on the back surface of the liquid crystal panel 2 and is emitted (emitted) from this surface, and is disposed on the front side of the light guide plate 42. The panel 10 is irradiated.

In this embodiment, the outer end surface 42 of the light guide plate 42
c and the front end of the overhanging frame portion 41d (the front ends of the liquid crystal panel 10 that protrude into the front housing portion 41b while supporting the end of the liquid crystal panel 10 behind) are fixed so as to fit tightly without gaps. The light from the light source 30 is
Light guide plate 42 with almost no leakage on the side where
And is used as a backlight for the liquid crystal panel 10. In particular, as shown in FIG. 6, leakage light from the peripheral portion of the liquid crystal panel 10 in the conventional structure is completely blocked by the overhanging frame portion 41d itself. It is possible to prevent the brightness of the display from being reduced.

Further, in order to secure the maximum effective display area of the liquid crystal display device as much as possible and to reduce the size of the device, the outer region (frame region) 10E of the liquid crystal panel and the peripheral region 40E of the panel support 40 are thinned. Even when it is necessary to form the support frame 41, it is possible to cope with it only by changing the shape of the support frame 41, and it is not necessary to change the assembling work itself, and it is not necessary to attach the reflective film. Since it can be easily performed, the manufacturing cost can be reduced. Further, automation of the assembling work can be easily performed.

FIG. 7 shows light reflection characteristics of a polycarbonate resin (white) suitable as a light reflection material of the frame portion 41 of the present embodiment. The measurement sample is a HR-3001NR (product number) 2 mm thick plate manufactured by Mitsubishi Engineering-Plastics Corporation. As described above, even a very thin plate material can be configured to exhibit a sufficient light reflectance over almost the entire visible light region.

FIG. 4 shows a modification of this embodiment. In this modification, the liquid crystal panel 10 has exactly the same structure as described above, and the panel support 50 is the same as the above embodiment except for an engagement portion 51c and an outer end surface 52c of the light guide plate 52 described later. is there. Accordingly, in this modification, the support frame 51 of the panel support 20, the overhang frame 51 d,
There is no change in the basic configuration such as the light guide plate 52.

In this modification, the support frame 51 of the panel support 50 receives the light guide plate 42 from above in the above embodiment (the front side, that is, the side on which the liquid crystal panel 10 is mounted). The light guide plate 52 is supported from below the support frame 51 (the rear side, that is, the side opposite to the side on which the liquid crystal panel 10 is mounted) without forming the contact support portion 41c configured to contact and support the light guide plate 52. Frame 5
1.
In this case, in order to hold the light guide plate 52 inside the support frame 51, an engagement portion 51c indicated by a dotted line in the drawing may be provided. The engaging portion 51c is provided with a light guide plate 52 introduced into the support frame 51.
Is formed with a hook-shaped overhanging portion that engages with the outer end of the horn. The engaging portion 51c connects the light guide plate 52 to the panel support 5.
0 from the rear side (the lower side in the figure), and
The light guide plate 52 is configured to be snap-engaged with the outer edge of the light guide plate 52 by being fitted inside the light guide plate 52. The method of holding the light guide plate 52 on the support body 51 is not limited to this, and the light guide plate 52 may be held by various methods such as bonding to the support frame 51 with a double-sided adhesive tape or the like.

In this modified example, an inclined surface portion 51f functioning as a light reflecting surface is formed on a support frame 51 similarly to the above embodiment. This modification differs from the above embodiment in that the outer end surface 52c of the light guide plate 52 is formed as an inclined surface inclined to a shape corresponding to the surface portion 51f. That is, the end portion of the light guide plate 52 is formed so as to greatly extend over the surface portion 51f,
The inclination of the outer end portion 52c of the light guide plate 52 (the angle formed by the back surface of the light guide plate 52 and the outer end portion 52c) and the inclination of the surface portion 51f (the angle of the tip of the overhanging frame portion 51d) are equal to each other. The surface of the outer end portion 52c is in contact with the surface portion 51f. When the light guide plate 52 is fitted into the support frame 51 as described above, and the engaging portion 51c is engaged with the outer edge of the light guide plate 52, the outer end surface 52c is almost exactly fitted to the surface portion 51f as shown in FIG. They are in close contact or substantially parallel to each other with a slight gap therebetween.

In this modification, the light emitted from the light source 30 passes through the optical opening 50a and is introduced into the light guide plate 52 from the back surface 52b of the light guide plate 52 which is not covered by the reflection film 53. Is done. This light is applied to the surface portion 5 that is closely or opposing to the outer end surface 52c of the light guide plate 52.
2c again reflects into the light guide plate 52,
Is reflected in a direction substantially along the surface of the plate.

In this modified example, in addition to the above-described embodiment, light leakage of light directly emitted from the light source 30 to the side where the liquid crystal panel is disposed through the space between the overhang frame 51d and the light guide plate 52 is described. And the overhanging frame 51
Since precise and high-precision assembly of the light guide plate 52 and the tip of d is not required, the assembling work can be easily performed. In this modification, the outer end surface 52c of the light guide plate 52
Are inclined so as to correspond to the inclination of the surface portion 51f, and are arranged in a mutually combined state.
Light leakage between the tip of 1d and the light guide plate 52 can be almost completely blocked.

It should be noted that the liquid crystal display device of the present invention is not limited to the illustrated example described above, and it goes without saying that various changes can be made without departing from the spirit of the present invention.

[0035]

As described above, according to the present invention,
By forming a surface part on the support frame of the panel support that reflects the incident light and introduces it into the light introduction surface of the light guide plate, it is no longer necessary to attach a belt-like reflective film as in the past, so it is assembled. Work can be facilitated, and light leakage from between the adhered reflective film and the panel support can be prevented.

[Brief description of the drawings]

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

FIG. 2 is a plan view showing a planar structure of the panel support in the embodiment.

FIG. 3 is an enlarged cross-sectional view showing the vicinity of a periphery of a liquid crystal panel in the same embodiment.

FIG. 4 is an enlarged sectional view showing a modification of the embodiment.

FIG. 5 is a schematic sectional view showing a structure of a conventional liquid crystal display device.

FIG. 6 is an enlarged sectional view showing the vicinity of the periphery of a liquid crystal panel of a conventional liquid crystal display device.

FIG. 7 is a graph showing light reflection characteristics of a thin plate of a white polycarbonate resin that can be used in an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Liquid crystal panel 11, 12 Substrate 40 Panel support 40a Optical opening 41 Support frame 41a Back side accommodating part 41b Front side accommodating part 41c Contact support part 41d Projection frame part 41e Panel support surface 41f Surface part 42 Light guide plate 42b Back part 42c Outer end face

Claims (5)

[Claims] 1. A liquid crystal display device comprising a liquid crystal panel and a panel support for supporting the liquid crystal panel, wherein the panel support has a light introduction surface and a light emission surface,
A light guide portion having a light guide function for emitting light introduced from the light introduction surface from the light exit surface to illuminate the liquid crystal panel, and a support frame portion formed of a light reflective material. A liquid crystal display device, wherein the support frame portion is provided with a surface portion disposed at a position facing or closely contacting the light introduction surface and reflecting incident light toward the light introduction surface side. 2. The liquid crystal display device according to claim 1, wherein the panel support is provided with an optical opening for allowing light to enter the surface. 3. The support frame according to claim 1, wherein the support frame is formed in a frame shape so as to surround the light guide.
The liquid crystal display device according to claim 1, wherein the light guide portion is a light guide plate accommodated in the support frame portion, and the light introduction surface is an outer end surface of the light guide plate. 4. One of claims 1 to 3
In the paragraph, the light guide section is a light guide plate arranged substantially in parallel with a panel surface of the liquid crystal panel such that the light emission surface faces the liquid crystal panel, and the light introduction surface is positioned relative to the panel surface. An end surface of the light guide plate that is substantially orthogonal, and the front surface portion of the support frame portion reflects incident light incident from the back side of the liquid crystal panel toward the light introduction surface side and introduces the light into the light guide portion. A liquid crystal display device characterized by being inclined with respect to both the panel surface and the light introduction surface. 5. The liquid crystal display device according to claim 4, wherein the light-reflective material has a white color.