JPH0481797B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a liquid crystal display device used in a portable small-sized color television or the like using a transmission type liquid crystal display device.

BACKGROUND ART In recent years, the performance of transmissive liquid crystal matrix display elements has been rapidly improved, and in particular, high-speed response and high contrast have been significantly improved, and their application to television screen displays has been put into practical use.

A transmissive liquid crystal matrix display device attempts to obtain a predetermined display on a display surface by arranging fine unit picture elements of liquid crystal in a matrix in the X and Y directions and illuminating the back surface from a light emitting source. In particular, when performing color display, filters of 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 with predetermined colors is obtained by the primary color additive method. An example 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 matrix 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. Since a light source that is close to a point light source is usually used as a light source, 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 the linear light source must be spread in the vertical direction of the linear light source to uniformly illuminate the entire display surface. be.

An example of this is shown in FIG. 7, for example. This is achieved by attaching a semi-transparent plate 43 to the back surface of the liquid crystal display panel 41 and providing a space between the liquid crystal display panel 41 and the light source body 42 in order to obtain uniformity of irradiation.

Another problem to be solved is the use of external light such as sunlight to reduce power consumption. If sufficient external light can be obtained by combining the above-mentioned irradiation with the built-in light source and the use of external light, the power consumption required for image display will be significantly reduced because there is no need to operate the built-in light source. It can be reduced.

As a conventional technique for making both such a built-in light source and external light compatible, there is a technique shown in FIG. 5, for example.

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, 23 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 reflective surface that diffusely reflects the light from the light source, and 38 is a light source. Further, L ₁ is external light such as sunlight.

First, in the case of operation using the built-in light source, the display panel 23 is tightly fixed to the light auxiliary plate 34, and the light source 3
8 to emit light. A portion of the light emitted from the light emitting source 38 passes directly through the linear light scattering surface 35 while being diffused.
In addition, a part of the light passes through the transparent plate 36 and is reflected onto the reflective surface 37, and is then repeatedly reflected onto the back surface of the light scattering surface 35, and illuminates the back surface of the display panel 23 through the same scattering surface 35.

In addition, in the case of operation using external light, the display panel 23
By opening and setting the light auxiliary plate 34 to an optimal angle, the external light _L1 is reflected on the surface of the light scattering surface 35, and the reflected scattered light reaches the back surface of the display panel 23.

Problems to be Solved by the Invention However, the above configuration has the disadvantage that it is difficult to obtain the brightness of the light that illuminates the back surface of the panel display element 23 in order to obtain a predetermined screen brightness. That is,
When using a built-in light source, a light scattering surface 35 that becomes a light emitting surface
Since the light emission is made of the direct light from the light source and the light repeatedly reflected inside the light auxiliary plate 34, there is a large unevenness of light between the two, and in order to equalize this, the transmission of the light scattering surface 35 is necessary. Since the diffusion rate must be increased, the transmittance decreases, and the brightness of the light emitting surface relative to the light emitted by the light source decreases significantly. To prevent this, you can either increase the brightness of the light source to increase the brightness of the light emitting surface, or use multiple light sources and use equalization by the light source itself, and use a light scattering surface with low diffusivity and high transparency. Both of these methods significantly increase the power consumption of the light source.

In addition, 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 liquid crystal display device that can efficiently obtain high brightness on the display surface in both cases of built-in light source and external light.

Means for Solving the Problems In order to achieve this object, the transmissive liquid crystal display device of the present invention has a reflective umbrella that is divided into a plurality of parts and has bendable joints. When the part is pulled out or pushed in, the opening opens and closes, and when it is pulled out, it forms a light source reflector with an arc-shaped or parabolic cross section, and when it is pushed in, it wraps around the light source and opens and closes the opening. It is characterized by being configured so that it closes.

Function With this configuration, when operating with a built-in light source, relatively highly uniform light from the light source directly illuminates the display panel diffusion surface, and when operating with external light, highly reflective light from a complete reflector plate illuminates the display panel. In either case, high screen brightness can be obtained because reflected light of a certain ratio can be obtained.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the entire transmissive liquid crystal display device according to an embodiment of the present invention, and shows the storage state of the device.

In Figure 1, 1 is the panel display section, 2 is the liquid crystal panel built into the panel display section 1, 3 is the diffuser plate attached to the back of the liquid crystal panel 2, and 4 is the light source, in this case the front side of the drawing. This shows a cross section of a straight tube fluorescent lamp installed facing away from the camera. 5,
Reference numerals 6, 7, and 8 denote members constituting a reflective umbrella, and each member has a substantially rectangular shape extending from the near side to the opposite side in the drawing. In this example, there are four members,
The members 5, 6, 7, and 8 are joined by three bendable joints. Reference numeral 9 denotes a movable part that is part of the housing and moves together with the sliding plate 10 relative to the main body part 11;
Reference numeral 1 denotes a main body portion constituting a housing, and 10 a sliding plate interposed between the main body portion 11 and the movable portion 9. 9' is a movable part reflecting mirror attached to the movable part 9, and 11' is a main body part reflecting mirror attached to the main body part 11. Reference numeral 5' denotes a hinge part connecting the reflectance member 5 and the main body part reflecting mirror 11', and 8' denotes a hinge part connecting the reflector member 8 and the movable part reflecting mirror 9'. In addition, 10' is a reflective umbrella member 6.
and 7 are fixed to the sliding plate 10 at the joints of the reflecting umbrella members 6 and 7, and move up and down with respect to the main body 11 in accordance with the sliding plate 10 while supporting the opening and closing of the reflecting umbrella members 6 and 7.

FIG. 2 shows a state in which the panel display section 1 is opened like a door with the lower end of the panel display section 1 as the center of rotation from the state shown in FIG. 1, and the panel display is operated using external light. FIG. 4 shows the case where the panel display operation is changed from the state shown in FIG. 1 to the operation using the built-in light source, and FIG. 3 shows the state in the middle of switching from FIG. 1 to FIG. 4.
The width dimension of the barrel reflective umbrella members 5 to 8 from the front side to the opposite side in the drawing sufficiently includes the width of a predetermined panel display.

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

First, the operation under external light will be explained using FIG. 2.

As shown in Fig. 2, the operation during external light is such that the external light entering the back side of the open panel display section 1 is reflected by the movable part reflecting mirror 9' and the main part reflecting mirror 11' being arranged in a flat plate shape and being almost integrated. The outside light is reflected by the external light reflecting mirror constituting the mirror surface of the surface and illuminates the diffuser plate 3. In this case, the diffuser plate has the effect of equalizing the unevenness of reflected light that occurs in the slight gap between the two reflecting mirrors. FIG. 1 shows the state shown in FIG. 2 with the panel display section 1 closed, and shows the portable form of a compact color television using a transmissive liquid crystal matrix display device.

Next, the case of transitioning from external light operation to built-in light source operation will be described. In FIG. 1, when the movable part 9 is pulled in the direction of the mark loss, the movable part 9 and the sliding plate 10 move together. This state is shown in FIG. In FIG. 3, the reflective umbrella support part 10' moves together with the sliding plate 10, while the reflective umbrella member 5 is extended between the main body part 11 and the hinge part 5', and the reflective umbrella member 6 is moved as a reflective umbrella member. 5, the joints of the reflective umbrella members 5 and 6 gradually widen until they reach the state shown in FIG. When the movable part 9 is further pulled from this state, the sliding plate 10 and the main body part 11 reach their full sliding range. Moving on. At this time, the reflecting umbrella support part 10' is fixed and the hinge part 8' of the reflecting member 8 connected to the movable part 9 moves upward, so that the reflecting members 7 and 8, which are jointed, gradually open. Eventually, the state shown in Figure 4 is reached. At this time, the reflecting umbrella members 5 to 8 form a reflecting mirror of the light source 4 in a combined state. This formation has an arc-shaped or parabolic cross-section, and has the effect of uniformly diffusing the luminous flux of the light source 4 over the entire display panel surface in an ideal form.

In FIG. 4, the built-in light source is in operation when the light source 4 is turned on. The diffuser plate 3 includes reflective umbrella members 5 to 8.
It has the effect of equalizing the unevenness of light that could not be completely absorbed by the small gaps between each and the diffusion effect of the reflective umbrella.

Furthermore, when returning to the storage state from the operation of the built-in light source, by pushing the movable part 8 in the direction of the arrow in FIG. Figure 1 shows a state in which the movable part 8' is bent and the movable part 8 is completely pushed in after passing through the state shown in Figure 3 on the way. becomes a plane mirror. This state is the stored state.

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, and when using external light, Since the fully reflective surface provides high reflectance, a high-brightness screen can be achieved.
Furthermore, in this embodiment, the space occupied by the reflector inside the housing when the built-in light source is operating is significantly reduced when stored and when operating with external light, making it easier to use the housing when carrying or using external light outdoors. Since the volume is significantly reduced, it is very convenient when the present invention is applied to a small color television as in this embodiment.

In this embodiment, in order to clearly explain the mutual movement of the movable part 9, the sliding plate 10, and the main body part 11, the sliding plate 10 is first moved from the main body part 11, and after this movement is completed, the movable part Although the order was such that the movable part 9 and the sliding plate 10 are moved from the sliding plate 10, this order may be reversed, or the movable part 9 and the sliding plate 1 can be moved in any order.
0 may move at the same time.

In this embodiment, the door movement of the panel display section 1, the sliding operation of the movable section 9, and the power input switch of the light source 4 are linked, so that when the panel display section 1 is open as shown in FIG. 9 was kept stationary, and the panel display section 1 was made not to open when the built-in light source was operating as shown in Figure 4, and when the power was input to the light source 4, the movable part 9 was pulled out completely as shown in Figure 4. If only the time is entered, malfunctions associated with switching operations between built-in light source operation and external light operation will be eliminated, and the functionality of this configuration will be further improved.

Effects of the Invention As described above, according to the present invention, the member constituting the reflective umbrella of the light source is configured to roll in conjunction with the sliding movable part, thereby achieving highly efficient reflection during external light operation. When the built-in light source is operating, a useful combination of direct light and reflected light can be obtained, so high brightness can be achieved both when the built-in light source is operating and when operating with external light without sacrificing the other. screen can be realized, and its practical effects are great.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the storage state of a transmissive liquid crystal display device according to an embodiment of the present invention, FIG. 2 is a sectional view showing the state when using external light, and FIG. 3 is a sectional view showing the state in the middle of switching. Sectional diagram showing, No. 4
The figure is a cross-sectional view showing the built-in light source when it is in operation.
Figures 6 and 7 are cross-sectional views showing conventional examples;
FIG. 1... Panel display section, 2... Liquid crystal panel, 3...
...Diffusion plate, 4...Light source, 5, 6, 7, 8...Reflector member, 9...Movable part, 9'...Movable part reflector,
10...Sliding plate, 10'...Reflector support part, 11
...Body part, 11'...Body part reflector, 21...
Liquid crystal, 22...pixel electrode, 23...color filter layer, 24...white light, 33...display panel,
34...Light auxiliary plate, 35...Light scattering surface, 36...
Transparent plate, 37... Reflective surface, 38... Light source, L ₁ ...
...External light, 41...Liquid crystal display panel, 42...Light source body, 43...Semi-transparent plate.

Claims (1)

[Claims] 1. When the movable part of the casing composed of a plurality of sliding members is pulled out from the main body part, the movable part is installed in a third movable part interposed between the main body part and the movable part. The reflector, which is made up of a member with a plurality of bendable joints, opens to form a light source reflector with an arc-shaped or parabolic cross section, and when the movable part is pushed in, the light source A transmissive liquid crystal display device in which an opening of a reflective umbrella closes to enclose the light source. 2. The liquid crystal display section that opens and closes and the movable section are linked, and when the liquid crystal display section is opened, the movable section does not move.
2. The transmissive liquid crystal display device according to claim 1, further comprising a mechanism that prevents the liquid crystal display section from opening when the movable section is pulled out. 3. The transmissive liquid crystal display device according to claim 1, wherein the power input switching means for the light source and the movable section are linked, and the light source can be inputted in a state where the movable section is pulled out.