JPH052149B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a transmissive liquid crystal display device that can be used in portable compact color televisions and the like.

BACKGROUND ART In recent years, the performance of transmissive liquid crystal display elements has been rapidly improved, and in particular, high-speed response and high contrast have been significantly improved, and they are now being applied to television screen displays.

A transmissive liquid crystal matrix display has minute liquid crystal unit pixels arranged in a matrix in the X and Y directions.
The purpose is to obtain a predetermined display on the display surface by illuminating the back surface from a light emitting source. In particular, when performing color display, filters for the three primary colors of red, green, and blue are attached to the unit pixels, and white light is irradiated from the back side arranged in a mosaic pattern.
A screen of a predetermined color is obtained by the additive coloring method of the three primary colors of green and blue. A conventional example of such a device is shown in FIG.

Here, 21 is a liquid crystal, 22 is a pixel electrode constituting a unit picture element, 23 is a color filter layer constituting a filter for the three primary colors of red, green, and blue, and 24 is white light irradiated from the back.

When this transmissive liquid crystal display element is used in an actual portable compact color television, there are several problems that must be solved.

One is irradiation by a low-power light source built into the device. Usually, something close to a point light source is used as a light source, so it is necessary to uniformly irradiate the entire display surface with this point light. In particular, in the case of color display, high quality white light is required, and photoluminescence is the most promising means to obtain white light with low power at the current state of the art. Specifically, a small cylindrical straight tube type fluorescent lamp is used, but in this case, the light from a linear light source is spread in the vertical direction of the linear light source to uniformly illuminate the entire display surface. There is a need.

As an example of such, for example, JP-A-51-
There is an explanatory diagram (shown in Figure 7) in Publication No. 32297,
In order to obtain uniformity of irradiation, a translucent plate 43 is attached to the back surface of the liquid crystal display panel 41, and a space is provided between the liquid crystal display panel 41 and the light source body 42 to achieve this purpose.

Another problem to be solved is how to utilize external light such as sunlight to reduce power consumption. By balancing the above-mentioned irradiation with the built-in light source and the use of external light, the built-in light source does not need to be operated when sufficient external light is available, significantly reducing the power consumption required for image display. I can do it.

As a conventional technique for achieving both the use of the built-in light source and the use of external light, there is, for example, the technique shown in FIG. 5 of Japanese Patent Application No. 119695/1983 filed by the same applicant. A conventional example will be described below with reference to FIG.

FIG. 5 is an example of a conventional transmissive liquid crystal matrix display device that has a built-in light source and external light compatibility functions. In FIG. 5, 33 is a display panel, 34
is a light auxiliary plate equipped with means for reflecting external light and a built-in light source. 35 is a light scattering surface which has the function of scattering and reflecting external light and at the same time diffusing and transmitting light from the back side. 36 is a transparent plate that guides and scatters the light from the light source, 37 is a reverse slope that diffuses and reflects the light from the light source, and 38 is a light source. Further, L ₁ is external light such as sunlight.

The operation of the transmissive liquid crystal matrix display device constructed as described above will be explained below.

First, in the case of operation using the built-in light source, the display panel 33 is closely fixed to the light auxiliary plate 34 and the light source 38 is turned on to emit light. A portion of the light emitted from the light source 38 directly passes through the light scattering surface 35 while being diffused, and a portion of the light passes through the transparent plate 36 and is reflected on the reflective surface 37, and further passes through the back surface of the light scattering surface 35. By repeating the reflection, the back surface of the display panel 33 is irradiated through the scattering surface 35 as well.

In addition, in the case of operation using external light, the display panel 33
By opening and setting the light auxiliary plate 34 to an optimal angle, external light L ₁ is reflected on the surface of the light scattering surface 35 and the reflected scattered light reaches the back surface of the display panel 33.

Problems to be Solved by the Invention However, the above configuration has a drawback that it is difficult to obtain the brightness of the light that illuminates the back surface of the panel display element 33 in order to obtain a predetermined screen brightness. That is,
When using a built-in light pole, a light scattering surface 35 becomes a light emitting surface.
Since the light emission is made of direct light from the light source and light repeatedly reflected inside the light auxiliary plate 34,
The light unevenness of both is large, and in order to equalize this, it is necessary to increase the transmission diffusivity of the light scattering surface 35, which reduces the transmittance and significantly reduces the brightness of the light emitting surface relative to the light emitted by the light source. Resulting in. To prevent this, either increase the luminance of the light source by increasing the luminance of the light emitting surface, or use multiple light sources and use the light source's own equalization to use a light scattering surface with low diffusivity and high transparency. , one of the following is possible,
Both significantly increase the power consumption of the light source.

Furthermore, in the case of external light, the reflection of external light is due to the translucent white scattering surface, so the reflectance is extremely low at a few percent, and therefore the brightness of the panel display surface that can be obtained is only extremely low. Nakatsuta.

In view of the above-mentioned problems, the present invention provides a transmissive display device that can efficiently obtain high brightness on the display surface both with a built-in light source and with external light.

Means for Solving the Problems In order to achieve this object, in the transmissive liquid crystal display device of the present invention, a perfect reflection plate having a screen-like finely divided structure is provided between the built-in light source and the diffuser plate integrated on the back surface of the display panel. The display panel is characterized in that the reflector plate is rotated in conjunction with opening and closing of the display panel.

Effect With this configuration, when operating with the built-in light source, the relatively highly uniform light of the light source directly illuminates the display panel diffusion surface, and when operating with external light, the highly reflective plate reflects the light with a high reflectance. Since light can be obtained, high screen brightness can be obtained in either case.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the main parts of a transmissive liquid crystal display device according to an embodiment of the present invention, and shows the case of operation using a built-in light source.

In Fig. 1, 1 is a panel display section, 1' is a panel locking claw attached integrally with the panel display section 1, and 2
is the liquid crystal panel built into the panel display section 1,
3 is a diffuser plate attached to the back surface of the liquid crystal panel 2, and 4 is a light source, which in this case represents a cross section of a straight tube type fluorescent lamp installed from the front side to the opposite side of the drawing. Reference numeral 5 denotes a reflective umbrella for the light source 4, and reference numeral 6 denotes an external light reflecting plate, which has a substantially rectangular shape with its longitudinal direction extending from the front side to the opposite side of the drawing, and rotates at the center of its short side. It is used. Reference numeral 6' denotes a rotation lever for rotating the external light reflecting plate 6, which is fixed at a constant angle to the external light reflecting plate 6. 7 is a drive lever that drives the rotation lever 6'. The longitudinal dimension of the approximately elliptical external light reflecting plate 6 covers the width of a predetermined panel display, and the rotary lever 6' is connected to one or both longitudinal ends of the external light reflecting plate 6 to cover the width of a predetermined panel display. Do not enter the width of Furthermore,
The drive lever 7 is attached to the side opposite to the external light reflecting plate 6 with the rotary lever 6' interposed therebetween. 7' is a projection attached to the drive lever, and 7' is a panel display opening/closing button integrated with the drive lever 7'.

Figure 2 also shows the case of operation due to external light,
The symbols are the same as the configuration in FIG. Figures 3 and 4
The figure shows the overall view of FIGS. 1 and 2, where 8 represents the casing of a small color television using the transmissive liquid crystal matrix display device of the present invention, and other symbols are the same as those in FIG. 1. It is.

The operation of the transmissive liquid crystal matrix display device configured as described above will be explained below.

First, the operation using the built-in light source will be explained with reference to FIG. Light emitted from the panel display side of the light source 4 passes between the open external light reflecting plates 6 and directly reaches the diffusing plate 2. Further, the light emitted from the back side of the light source is reflected by the light source reflector 5, which has a parabolic shape and has a mirror-finished inner surface, and reaches the diffuser plate as well. in this case,
The light source reflector has a mirror surface that exhibits complete reflection, and has a parabolic shape, so it can reflect at an extremely high rate, and there is little unevenness between the direct light and reflected light from the light source, and moreover, at high illuminance, it almost covers the diffuser plate 3. It also becomes possible to irradiate uniformly. On the other hand, the external light reflecting plate 6 has a thin streamlined cross-section with mirror surfaces on both sides, and the shadow cast on the diffuser plate by the irradiation from the light source is reduced by diffused reflection performed by each reflecting plate.

A diffusion plate 3 is provided to prevent uneven light on the screen due to shadows generated by the external light reflection plate 6, but since the reflection umbrella 5 has a uniformity effect, the diffusion effect is relatively small. Therefore, a diffuser plate with high transmittance can be used.

With these configurations, the loss of light from the light source is extremely small, and therefore a high-brightness screen can be realized with low power consumption.

Next, a state in which the operation of the built-in light source is switched to the operation based on external light will be explained. In FIG. 1, the drive lever 7 is always biased by a spring force in the direction of the arrow. Further, as shown in FIG. 4, a spring force is always applied to the panel in the door opening direction. Now, in Fig. 1, when the panel display opening/closing button 7'' is pressed, the drive lever moves downward by overcoming the spring force applied to the drive lever force, and the panel locking claw 1' and the drive lever are moved downward. However, since a spring force is applied to the panel display section 1 in the door opening direction, the panel display section 1 opens as shown in FIG. At the same time, the driving lever 7 is pushed upward by the biased spring force, and at the same time pushes up the rotary lever 6' connected to each external light reflecting plate 6 at a certain angle.This action causes the external light reflecting plate to 6
The light source reflector 5 rotates 90 degrees counterclockwise all at once, blocking the exit of the light source reflector 5, and is arranged in a flat plate shape, so that the entire body has a substantially flat mirror surface.

As shown in Fig. 4, the operation under external light is such that the external light that enters the back side of the open panel display area is reflected by the external light reflecting mirror, which is lined up on a flat plate and has a substantially mirror surface, and is reflected by the diffuser plate. 3. In this case, the diffuser plate has the effect of equalizing the unevenness of reflected light caused by the slight gap between the external light reflecting plates.

Next, a case will be described in which the operation shifts from outside light to built-in light source operation. In Figures 2 and 4, when the panel display section 1 is pushed in the door closing direction, the panel locking claw 1' is pushed into the housing, and the sloping part provided at the tip of the locking claw 1' acts. When the projection 7' provided on the drive lever 7 is pushed down, and the panel display section 1 is completely pushed in, the locking pawl 1' engages with the projection 7' due to the spring force applied to the drive lever 7. Otherwise, the panel display section will be fixed to the housing. At this time, the drive lever is pushed downward again, and the external light reflecting plate 6 is rotated 90 degrees clockwise by the rotation lever 6', returning to the operating state of the built-in light source described at the beginning.

As described above, according to this embodiment, the built-in light source uses the light from the light source in a way with less loss due to direct light and highly reflected light, so it can be used very efficiently. Since the fully reflective surface provides high reflectance, a high-brightness screen can be realized.
Furthermore, in this embodiment, switching between the built-in light source and the optical system using external light is completely linked to the opening/closing operation of the panel, and the optical system is automatically switched by simply opening/closing the panel without any special operations. It also has the advantage of being switchable.

In this embodiment, the nine external light reflecting plates had the same streamlined cross-sectional shape, but each of the nine external light reflecting plates had a cross-sectional shape that was concave with respect to the panel display section 1 when the external light was in operation. If the reflective surface is made to have a spherical or cylindrical concave shape relative to the panel display section, external light will be condensed and directed toward the panel display section, making it possible to obtain a brighter image.

Furthermore, if you change the fixed angle of the external light reflector and the rotary lever slightly for each external light reflector, for example, when operating with the built-in light source, you can set the angle of the external light reflector at a different angle between the central part and the periphery. Either minimize the shadow of the external light reflector caused by direct light, or change the angle little by little from the side closest to the center of opening/closing the panel display to the opposite side when operating with external light. It is also possible to achieve highly uniform screen brightness.

Effects of the Invention As described above, according to the present invention, highly efficient reflected light can be obtained when outside light is provided by the screen-like reflector that rotates in conjunction with the panel display section that opens and closes, and when the built-in light source is used, it is possible to obtain reflected light from the light source. Direct light and reflected light reach the diffuser plate without being obstructed by the reflector, allowing efficient irradiation, making it possible to achieve a high-brightness screen without sacrificing anything else, whether using the built-in light source or outside light. , its practical effects are great.

[Brief explanation of the drawing]

FIG. 1 is a main part diagram showing the operation of a transmissive liquid crystal display device according to an embodiment of the present invention using a built-in light source, FIG. 2 is a main part diagram showing the operation in external light, and FIGS. 3 and 4. is the overall diagram, Figures 5 to 7
The figures are a sectional view and a perspective view showing a conventional example. 1...Panel display section, 1'...Latching claw, 2...
Liquid crystal panel, 3...Diffusion plate, 4...Light source, 5...
Reflective umbrella, 6...External light reflector, 6'...Rotary lever,
7... Drive lever, 7'... Protrusion, 7''... Open/close button, 8... Housing, 21... Liquid crystal, 22... Pixel electrode, 23... Color filter layer, 24... White light, 33 ... Display panel, 34 ... Light auxiliary board, 3
5...Light scattering surface, 36...Transparent plate, 37...Reflecting surface, 38...Light source, _L1 ...External light, 41...Liquid crystal display panel, 42...Light source body, 43...Semi-transparent plate .

Claims (1)

[Scope of Claims] 1. A mechanism is provided that rotates a reflecting plate provided between the liquid crystal display and a light source on the rear surface of the liquid crystal display by opening and closing the liquid crystal display, When the reflector is brought close to the reflector, the reflector is tilted parallel to the direction connecting the liquid crystal display and the light source, and when the liquid crystal display is separated from the reflector, the reflector is oriented at right angles. Transmissive liquid crystal display device. 2. When a plurality of reflectors are provided, and the cross-sectional shape of each of the plurality of reflectors is changed and rotated at right angles to the direction connecting the liquid crystal display section and the light source, the plurality of reflectors as a whole can be used as a whole when viewed from the liquid crystal display section. Claim 1 in which a concave spherical surface or a parapet surface is formed.
Transmissive liquid crystal display device as described in . 3. The transmission according to claim 1, wherein a plurality of reflecting plates are provided, and the set angles of the plurality of reflecting plates are gradually changed from one end side to the other side, or gradually changed from the center to both sides. type liquid crystal display device.