JPH08304821A - Display device - Google Patents

Abstract

PURPOSE: To reduce power consumption, to lengthen a battery duration and the fluorescent tube life and to brighten the fluorescent tube by using external light together with a back light. CONSTITUTION: The external light incident from an external light take-in window 26 irradiates a rear surface of a liquid crystal panel 11. When no external light is obtained sufficiently, the fluorescent tube 22 of a back light part 23 is lighted, and the external light is used together with the back light. Further, when the device is used in night and within doors where no external light is taken in perfectly, a monitor part 14 and the external light take-in window 26 are turned around a shaft 15, and the external light take-in window 26 is stored in a housing 16, and the monitor part 14 is made oppose to a prism sheet 18, and when the fluorescent tube 22 is lighted, the liquid crystal panel 11 is irradiated directly from the rear surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for a monitor screen of a portable liquid crystal television device or a video camera,
The present invention relates to a backlight type display device including a transmissive display panel.

[0002]

2. Description of the Related Art FIG. 5 is a sectional view of a backlight display portion in a conventional liquid crystal display device.

As shown in FIG. 5, the backlight portion of a liquid crystal display device of this type is arranged on the back surface of a liquid crystal panel 3 made of a fluorescent tube 2 which is a light source surrounded by a reflection plate 1 and a liquid crystal display substrate. And a light guide plate 4. Further, between the liquid crystal panel 3 and the light guide plate 4, a prism sheet 5 for efficiently deflecting the light from the fluorescent tube 2 in the direction of the liquid crystal panel 3 and a scattering plate 6 for eliminating unevenness in the brightness of the light are provided. Intervened. Further, a reflection plate 7 is provided on the back side of the light guide plate 4 so that the light of the fluorescent tube 2 does not leak out.

As a result, the light from the fluorescent tube 2 as a light source passes through the light guide plate 4, part of which is directly reflected by the reflector 7, and the liquid crystal panel through the prism sheet 5 and the scattering plate 6. 3 will be transmitted. On the other hand, the liquid crystal panel 3
Then, the liquid crystal can be driven according to the display voltage signal so that light from the fluorescent tube 2 can be transmitted or shielded for display.

[0005]

However, in the above-mentioned conventional liquid crystal display device, when trying to see the display screen of the liquid crystal panel 3, it is necessary to keep the fluorescent tube 2 serving as a light source constantly emitting light, and the power for that purpose is required. Had to be continuously supplied to the fluorescent tube 2. Therefore, there is a problem that the fluorescent tube 2 consumes a large amount of power and the life of the fluorescent tube 2 is shortened.

Further, in recent years, this liquid crystal display device has come to be used as a portable liquid crystal television device or the like or as a monitor screen of a video camera, and since a rechargeable battery is used as its power source, Development of a liquid crystal display device with low power consumption is desired. In addition, when used outdoors such as a video camera, the sunlight tends to enter the monitor screen and the screen tends to be darker than when used indoors. Therefore, it is necessary to make the brightness of the fluorescent tube 2 brighter, and there is a problem that the amount of power consumption is further increased and the duration of the battery is further shortened.

The present invention solves the above-mentioned conventional problems. By using external light and a back light together, the power consumption can be reduced, the battery duration and the fluorescent tube life can be extended, and a bright display can be obtained. The purpose is to provide a device.

[0008]

A display device of the present invention is a display device having a transmissive display panel for controlling and displaying transmitted light by driving a display medium, and an external light capturing window for capturing the external light, The light guide means for guiding the outside light taken in through the outside light taking-in window to the transmissive display panel is provided, thereby achieving the above object.

Preferably, the display device of the present invention is
In a backlight type display device having a transmissive display panel for controlling and displaying transmitted light by driving a display medium, an external light capturing window for capturing the external light and the external light captured through the external light capturing window The light guide means for guiding the backlight light to the transmissive display panel and the light quantity control means capable of controlling the light quantity of the backlight light are provided, thereby achieving the above object.

Further, preferably, the display device of the present invention is a backlight type display device having a transmissive display panel for controlling and displaying transmitted light by driving a display medium, and taking in external light. A window, a light guide means for guiding the outside light and the backlight light taken in from the outside light intake window to the transmissive display panel, and a light quantity control means for controlling the quantity of the backlight light. The light-intake window, the light guide means, and the transmissive display panel are integrally constructed and rotatably supported, and the outer light-intake window can be opened or stored by the rotation. There, the above object is achieved thereby.

Further, preferably, the display medium in the display device of the present invention is liquid crystal.

[0012]

In the present invention, the outside light taking-in window is opened whenever it is desired to utilize the outside light, so that the outside light can be efficiently guided to the display panel surface from the window made of, for example, a prism sheet. Can be used with lights. Further, when outside light cannot be used, this window can be housed to efficiently guide the light from the backlight to the display panel surface. In this way, by using the external light and the backlight light together, the external light is used, so that the power consumption is reduced, the battery duration and the fluorescent tube life are extended, and a bright display is obtained. .

[0013]

Embodiments of the present invention will be described below.

1A and 1B show a state of a liquid crystal display device according to an embodiment of the present invention incorporated in a video camera when using external light. FIG. 1A is its sectional view and FIG. 1B is its side view. .

In FIGS. 1A and 1B, a liquid crystal panel 11 which is a monitor screen is provided at the center of the video camera.
Is attached. The liquid crystal panel 11 is composed of, for example, an active matrix type liquid crystal display element, and an external drive circuit 12 supplies a display voltage signal to the liquid crystal panel 11 to drive the liquid crystal to control the amount of transmitted light and display a subject on a monitor. I do. A diffusion plate 13 is arranged on the back surface of the liquid crystal panel 11. The monitor unit 14 including the liquid crystal panel 11 is rotatably supported by the housing 16 by a shaft 15 provided at one end of the monitor unit 14.

A prism sheet 18 is attached to the front surface of the prism portion 18 so as to face the diffusion plate 13 with a space 17 separated from the monitor portion 14, and a light guide plate 19 is arranged on the back surface side of the prism sheet 18. A reflection plate 20 is attached to the back surface of the light guide plate 19. A fluorescent tube 22 surrounded by a reflection plate 21 is arranged on the lower side surface of the light guide plate 19 so that light is collected in the longitudinal direction of the light guide plate 19.
These diffuser plate 13, prism sheet 18 and light guide plate 1
9. The light guide means is constituted by the reflection plate 20 and the reflection plate 20, and guides the external light and the backlight light taken in through the external light taking-in window 26 to the liquid crystal panel 11 as a transmissive display panel. From the light guide means, the reflection plate 21 and the fluorescent tube 22 to the backlight unit 23.
Is configured. A light amount control means capable of controlling the light amount of the backlight light from the fluorescent tube 22 is provided, and the light amount of the backlight light can be controlled according to the indoor and outdoor light amounts.

Further, above the space portion 17, there is provided an outside light taking-in window 26 made of a prism sheet 25 attached to the upper part of the housing 24 of the monitor portion 14, and as the monitor portion 14 rotates. It is configured to rotate. A housing recess is provided inside the upper side of the housing 16 for housing the outside light taking-in window 26 by rotating.

Further, as shown in FIG. 1B, a protective cover 27 is provided on the side surface of the video camera parallel to the plane of the drawing so as to prevent dust and dirt from entering the space 17 of the monitor 24. Is attached to. At this time, the protective cover 27 also rotates together with the monitor unit 14. Further, it is desirable that the protective cover 27 be transparent or formed of a prism sheet so that external light that strikes the side surface of the video camera can be efficiently taken in. Further, the inside of the protective cover 27 may be a mirror surface so that the outside light incident from the outside light intake window 26 at the upper portion does not leak from the side surface.

With the above configuration, the operation will be described below.

First, the external light incident from the external light intake window 26 illuminates the back surface of the liquid crystal panel 11. In this state,
By driving the liquid crystal panel 11 via the drive circuit 12, a bright monitor image is displayed by receiving the external light. At this time, if sufficient bright external light is obtained,
Since the fluorescent tube 22 of the backlight unit 23 is turned off by the light amount control means and is not used, the power consumption can be significantly reduced and the lifetime of the fluorescent tube 22 which is the light source of the backlight unit 23 is extended.

Further, when the outside light is not sufficiently obtained due to the shade, cloudy weather, etc., the fluorescent tube 22 of the backlight unit 23 is used.
It is possible to display a bright monitor image by appropriately turning on the light by means of the light amount control means and using the external light and the backlight light together. In this case, since the backlight light is bright enough as the auxiliary light, it is possible to save power consumption.

Further, when used at night or indoors where outside light cannot be taken in at all, as shown in FIG.
The monitor unit 14 and the housing 24 are rotated around the center to store the outside light intake window 26 in the housing recess of the housing 16, and the monitor unit 14 and the prism sheet 18 of the backlight unit 23 face each other and contact each other. When the fluorescent tube 22 of the backlight unit 23 is turned on in this state, the liquid crystal panel 11 can be directly illuminated from the back side thereof, so that a bright monitor image can be obtained even in a dark place.

Therefore, in the liquid crystal display device having the liquid crystal panel 11, the fluorescent tube 22 serving as an illumination light source, and the external light receiving window 26 that can be stored, the liquid crystal panel 11 is rotatably supported by the external light. When the light is taken in, the liquid crystal panel 11 is opened as shown in FIG. 1, and the external light taking-in window 26 appears and opens, and the external light can be taken in through it, and the light can also be taken in from the backlight unit 23. Further, when the liquid crystal panel 11 is closed, the outside light taking-in window 26 is housed in the housing 16 as shown in FIG. 2, and it can be configured to take in light only from the backlight unit 23. In other words, a configuration in which the outside light intake window 26 can be opened or stored and the outside light can be used can be obtained by a simple opening / closing operation only by rotating the monitor unit 14 and the housing 24 without using a special adapter. , It does not add weight. Further, since the increase in the volume of the main body is relatively small due to the deformation caused by the opening or the storage, there is no problem even when the main body is adopted in a portable camera such as a video camera.

The prism sheet 25 of the outside light taking-in window portion 26 of FIG. 1 is constructed so that light incident from all directions can be efficiently directed to the back surface direction of the liquid crystal panel 11, for example, as shown in FIG. As shown in the drawing, the light B having a triangular cross section and incident obliquely can be converted into the light B ′ in a certain direction of the liquid crystal panel, or the Fresnel as shown in the plan view of FIG. A lens sheet, a microlens group as shown in FIG. 3C, or a lens sheet shown in FIG.
As shown in FIG. 4A, it is an n-pyramid (n is an integer) (in FIG. 4A, it is a quadrangular pyramid and includes a cone), and FIG.
3A, the prism sheet of FIG. 3A may be arranged in a patch shape by changing its groove direction.

Although the liquid crystal display device has been described in the present embodiment, a display device using a display medium other than liquid crystal which requires a backlight may be used.

Further, in this embodiment, the external light intake window 2
6, a part of the light guide means, a diffusion plate 13, and a liquid crystal panel 1.
1 is integrally configured, the external light intake window 26 and the liquid crystal panel 11 and the diffusion plate 13 may be separately configured. In short, the external light intake window 26 is opened or accommodated by a lid or a door. It only needs to be freely configured.

[0027]

As described above, according to the liquid crystal display device of the present invention, since it is not necessary to use the backlight when the outside light can be sufficiently taken in, it is possible to significantly reduce the power consumption, The battery can be downsized or used for a long time. In addition, even when the outside light is not sufficiently obtained due to the shade or cloudy weather, by using the outside light and the backlight light together, the backlight light will be as bright as the auxiliary light, which is enough power consumption. You can save electricity. In this way, the life of the fluorescent tube as the backlight can be extended by using the external light. Further, with this configuration, there is no large increase in volume or weight when taking in external light.

[Brief description of drawings]

FIG. 1 shows a state in which a liquid crystal display device according to an embodiment of the present invention incorporated in a video camera uses external light,
(A) is the sectional view and (b) is the side view.

2A and 2B show a state of the liquid crystal display device of FIG. 1 in a case where outside light is not used, FIG. 2A is a sectional view thereof, and FIG. 2B is a side view thereof.

3 (a) to 3 (c) are external light intake window portions 2 of FIG.
It is a figure which shows each Example of the prism sheet 25 in FIG.

4 (a) and 4 (b) are diagrams showing respective other examples of the prism sheet 25 in the external light intake window portion 26 of FIG.

FIG. 5 is a cross-sectional view of a backlight display portion in a conventional liquid crystal display device.

[Explanation of symbols]

 11 Liquid crystal panel 12 Drive circuit 13 Scattering plate 14 Monitor part 15 Shaft 17 Space part 18,25 Prism sheet 19 Light guide plate 20,21 Reflector plate 22 Fluorescent tube 23 Backlight part 26 External light intake window

Claims (4)

[Claims] 1. A display device having a transmissive display panel for controlling and displaying transmitted light by driving a display medium, the external light taking-in window taking in the external light, and the external light taking in from the external light taking-in window. And a light guide means for guiding the light to the transmissive display panel. 2. A backlight type display device having a transmissive display panel for controlling and displaying transmitted light by driving a display medium, the external light taking-in window taking in the external light, and taking in from the external light taking-in window. A display device comprising: a light guide unit for guiding the outside light and the backlight light to the transmissive display panel; and a light amount control unit capable of controlling the light amount of the backlight light. 3. A backlight type display device having a transmissive display panel for controlling and displaying transmitted light by driving a display medium, the external light taking-in window taking in the external light, and taking in from the external light taking-in window. The light guide means for guiding the outside light and the backlight light to the transmissive display panel and the light quantity control means for controlling the light quantity of the backlight light are provided, and the outside light taking-in window can be opened or stored. Display device. 4. The display medium is a liquid crystal.
The display device according to any one of the above.