JP2005292546A - Liquid crystal display device of low power consumption - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device that neither increases the space of a solar battery panel 6 nor causes a decrease in luminance. <P>SOLUTION: The liquid crystal display device having a light guide plate which guides light to a liquid crystal display panel has the solar battery panel right opposite at least one end surface of the light guide plate which is not opposed to a light source. Further, the solar battery panel is arranged nearly in parallel along a flank where the light source is not arranged. In a back light unit which has no light guide plate and which has a hollow housing, the solar battery panel is arranged along a flank where no light source is arranged in the housing. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a structure suitable for low power consumption in a liquid crystal display device using a backlight unit that irradiates a liquid crystal panel.

  In a conventional liquid crystal display device, an optical sheet, a light source, a light guide plate, a reflective sheet, an optical element, and a panel for converting the light energy into electric energy (hereinafter referred to as a solar cell panel) are provided as illumination means at the bottom of the liquid crystal panel. It has a built-in backlight unit. The light leaking from the end face of the light guide plate in the backlight unit is received by the solar cell panel to obtain electric power, which is used as circuit driving electric power, thereby realizing low power consumption.

  For example, in the first embodiment of Patent Document 1, as shown in FIG. 6, light 3e leaking from the end face of the light guide plate 4 is reflected by the optical element 7 on the side opposite to the irradiated surface, and is provided on the lower surface. To receive power. Further, in the second embodiment of Patent Document 1, as shown in FIG. 7, the solar cell panel 6 is disposed on the entire surface opposite to the illumination surface of the light guide plate, and the light 3f leaks to the light guide plate counter-lighting surface side. The light 3e leaking from the end face of the light guide plate 4 is combined and received by the solar cell panel 6 to obtain power.

JP 2003-84281 A

  However, in the above-described conventional technology, the optical element 7 is required to reflect the loss light on the end face of the light guide plate so that it can be received by the solar cell panel. The arrangement space of the optical element 7 and the arrangement of the solar cell panel 6 are necessary. The space will increase the external size of the backlight unit and the liquid crystal display device. Moreover, when the solar cell panel 6 is arranged on the entire surface of the light guide plate reflecting surface as in the second embodiment of Patent Document 1, the light 3f leaking from the light reflecting surface of the light guide plate is originally transmitted to the reflecting sheet 5. However, since the solar cell panel 6 is located on the entire surface opposite to the illumination surface of the light guide plate instead of the reflection sheet 5, the solar cell panel 6 absorbs light and the reflected light is reflected. There is a problem that the brightness is reduced due to the loss.

  An object of the present invention is to provide a liquid crystal display device that does not increase the space of the solar battery panel 6 and does not cause a decrease in luminance.

  The liquid crystal display device of the present invention is a liquid crystal display device having a light guide plate that guides light to the liquid crystal display panel, and includes a solar cell panel facing at least one end surface of the light guide plate not facing the light source. It is. Further, the solar cell panel is arranged substantially in parallel along the side surface where the light source is not arranged.

  Further, in a backlight unit having a hollow housing without a light guide plate, a solar cell panel is disposed along a side surface in the housing where a light source is not disposed.

  According to the present invention, the space for arranging the solar cell panel in the backlight unit can be suppressed as much as possible, so that the external size of the backlight unit and the liquid crystal display device can be reduced as compared with the conventional liquid crystal display device. . In addition, since the light that is originally lost is used instead of using the light necessary for irradiating the liquid crystal panel, the luminance of the liquid crystal display device does not need to be reduced.

Embodiment 1
FIG. 1 is a top view of a liquid crystal display device according to Embodiment 1 of the present invention. 2 is a cross-sectional view taken along the line AA in FIG. FIG. 3 is a perspective view of the liquid crystal display device of FIG.

  The liquid crystal display device of the present invention includes a liquid crystal panel 1, an optical sheet 2, a light source 3, a light guide plate 4, a reflection sheet 5, and a solar cell panel 6. The light 3 a emitted from the light source 3 is contained in the light guide plate 4. It passes through and becomes scattered light 3b. Further, the light that passes through the counter-irradiation surface and is reflected by the reflection sheet 5 passes through the light guide plate 5 again to become the light 3 c, and is irradiated to the liquid crystal panel 1 through the optical sheet 2.

  As shown in FIG. 1, the light 3a emitted from the light source 3 passes through the light guide plate 4 to the end face of the light guide plate 4 where the light source 3 is not disposed, and becomes lost light. There is also light 3d. The solar cell panel 6 is disposed perpendicular to the light 3d emission direction (that is, facing the end face of the light guide plate). The solar cell panel 6 receives the light 3d, converts the light energy into electric energy, and obtains electric power for driving the liquid crystal display device. The light 3d which is originally lost light can be reused, and a liquid crystal display device with low power consumption can be realized. Further, by arranging the solar cell panel 6 perpendicularly to the light 3d emission direction, the solar cell panel 6 need only have an arrangement space corresponding to the thickness of the solar cell panel 6. Therefore, the outer size of the backlight unit and the liquid crystal display device can be reduced.

Embodiment 2
FIG. 4 is a top view of a liquid crystal display device according to Embodiment 2 of the present invention. 5A is a cross-sectional view taken along the line BB in FIG. 4, and FIG. 5B is a cross-sectional view taken along the line CC in FIG.

  In the present embodiment, the backlight does not use a light guide plate, and the backlight housing 8 is hollow. The light emitted from the light source 3 provided along the side surface 8 a of the housing 8 is refracted by the optical element 7 and directed toward the bottom surface of the housing 8. There is a reflection sheet 5 on the bottom surface of the housing 8, and light is scattered and reflected by the reflection sheet 5. The reflected light passes through the optical sheet 2 provided in the opening of the housing 8 and is irradiated to a liquid crystal panel (not shown).

  Here, a part of the light refracted by the optical element 7 and a part of the light scattered and reflected by the reflection sheet 5 are directed to the side surface 8b in the housing 8 where the light source 3 is not provided. Therefore, the solar cell panel 6 is arranged on a part or the whole of the side surface 8b where the light source 3 is not provided in the housing 8, receives light directed toward the side surface 8b, converts light energy into electrical energy, Electric power for driving the liquid crystal display device is obtained.

  In the present embodiment, the space for installing the solar cell panel 6 only needs to be equal to the thickness of the solar cell panel 6. Therefore, the outer size of the backlight unit and the liquid crystal display device can be reduced.

  Conventionally, the side surface in the backlight housing where the light source is not disposed may be a reflecting plate. Since the reflecting plate can be reused by reflecting light, the light irradiated on the side surface on which the light source is not disposed can be used effectively. When a solar cell panel is compared with a case where a reflector is used, the solar cell panel absorbs light, and it is difficult to reuse the light applied to the side surface on which the light source is not arranged. Therefore, by making the surface of the solar cell panel of the present invention white or the like that easily reflects light, a part of the light irradiated to the solar cell panel can be reflected and reused. It is possible to effectively use the light irradiated to the. In addition, the external size of the backlight unit and the liquid crystal display device can be reduced while reducing power consumption.

1 is a top view of a liquid crystal display device according to Embodiment 1 of the present invention. It is AA sectional drawing of the liquid crystal display device of FIG. 1 is a perspective view of a liquid crystal display device according to Embodiment 1 of the present invention. It is a top view concerning Embodiment 2 of this invention. FIG. 5 is a cross-sectional view of FIG. 4. (A) is a BB cross section, (b) is a CC cross section. It is sectional drawing of the liquid crystal display device which shows 1st Example of a prior art. It is sectional drawing of the liquid crystal display device which shows the 2nd Example of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal panel 2 Optical sheet 3 Light source 3a The path | route of the light emitted from the light source 3 3b The path | route of the light emitted from the light source 3 3c The path | route of the light emitted from the light source 3 3d The path | route of the light emitted from the light source 3 3e The path of the light 3f The path of the light emitted from the light source 3 4 The light guide plate 5 The reflection sheet 6 The solar cell panel 7 The optical element

Claims (3)

In a liquid crystal display device having a liquid crystal display panel, a light source that irradiates the liquid crystal display panel, and a light guide plate that guides light emitted from the light source to the liquid crystal display panel, at least one of the light guide plate that is not suitable for the light source A liquid crystal display device comprising a panel for converting light energy into electric energy so as to face one end face. The liquid crystal display device according to claim 1, wherein the panel that converts the light energy into electric energy is disposed on an end face of the light guide plate that is not directly facing the irradiation direction of the light source. In a liquid crystal display device having a liquid crystal display panel and a planar light source device that irradiates the liquid crystal display panel, light energy is converted into electrical energy on a side surface of the planar light source device in which a light source is not provided. A liquid crystal display device comprising a panel.

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