JPH0155459B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid crystal display device that displays multiple colors.

[Conventional example]

In general, liquid crystal display elements are used in various display devices because it is easy to form electrode shapes that correspond to the display pattern, and color displays using synthetic resin color filters or colored polarizing plates have improved visibility and It has been widely used.

This type of color display provides an extremely good visual effect to ensure that each display information is clearly understood, especially when there are many types of display parts, and is also effective in giving the display device a high-class image. The device also employs a multicolor display as shown in FIG. 1, for example.

In other words, it is common to use a transparent plate as a color layer for this type of multicolor display, which is printed with different colors corresponding to each display part, and to provide a clear display using transmitted illumination from a rear light source. be.

The configuration shown in FIG.
Disclosed in Publication No. 142685.

The liquid crystal display element 1 is a TN liquid crystal display element having neutral polarizing plates 2 on both sides of which the respective light absorption axes are parallel.
Adopt a type cell. The liquid crystal display element 1 also has a counter electrode section 3 of a predetermined shape formed on the inner surface of the opposing transparent substrate. In this case, when a voltage is applied to the electrode section 3 formed as a display section, the liquid crystal display element 1 becomes transparent. On the front side of the liquid crystal display element 1, a front panel 5 is provided, in which each display window 4 through which the electrode section 3 can be seen is formed. Around each display window 4 of the front panel 5, scales, characters, etc. representing the magnitude of the displayed value are printed. Behind the liquid crystal display element 1 is a color filter 6 made of synthetic resin.
will be arranged. The color filter 6 has a plurality of different transparent color printed parts 8 formed on the surface of a colorless transparent plate 7. The color printing section 8 is formed at a position that matches the shape of the display section formed by the electrode section 3 and corresponds to the shape. A white semi-transmissive reflection plate 9 is disposed behind the color filter 6. Transflective plate 9
transmits the irradiated light from the rear light source 10 to enable transmitted illumination of the liquid crystal display element 1 at night, and also reflects bright external light during the day to enable clear multicolor display during the day and night. .

In other words, the multicolor display in the above conventional structure is
This is done by seeing through the color printing section 8 using the shutter effect of the liquid crystal display element 1. When a display signal corresponding to an external measurement amount is selectively applied to the electrode portion 3 of the liquid crystal display element 1, only the corresponding portion becomes a transparent state, and the color behind the liquid crystal display element 1 is transmitted through the display window 4 of the front panel 5. Color printing section 8 formed on filter 6
is visible. As a result, each display section displays a display in each corresponding color tone by changing the display area according to the measured amount.

It is also conceivable that a light source 10 is provided in a place where external light is used, and the light from this light source 10 is guided by a light guide plate (not shown) for illumination. In this case, the transflective plate 9 is not provided, but a light guide plate is attached to the back surface of the color filter 6. When displaying, the light source 10 is always turned on, and the light is colored by passing through the color filter 6, and the liquid crystal display element 1 described above is colored.
By transmitting the display signal to the selected portion, a display in each corresponding color tone appears.

[Problem to be solved by the invention]

However, in the case of a liquid crystal display device using a transflective plate 9, the transflective plate 9 is functionally unavoidable.
This reduces the irradiation light from zero by half, and effective irradiation is required to illuminate the liquid crystal display element 1 brightly. In particular, when a color filter 6 is provided to display a multicolor display as in the conventional structure described above, it becomes difficult to obtain bright illumination due to the light attenuation effect caused by the colorless transparent plate 7 and the color printing section 8. . In addition, instead of displaying multiple colors using the color filter 6, a method has been proposed in which one or both sides of the transflective plate 9 are printed in different colors corresponding to each display area, but in this case, the dedicated color filter 6 Although the structure is simplified by integrating both of them without the need to form them, the range of directivity provided to the transflective plate 9 is limited by direct color printing, and it is difficult to see clearly depending on the viewing direction. It has the disadvantage that the quality is lost.

That is, the transflective plate 9 is made of a colorless and transparent thin plate made of synthetic resin, such as acrylic, and is made of a pearl pigment mixed with silicon dioxide etc. to obtain directivity, and a white paint that is made into a thin film to obtain a semi-transparent function. It is common to use laminated printing and slightly roughen the other side to make it a diffusive surface, which equalizes the amount of reflected or transmitted light and controls brightness, but color printing for multicolor display is common. Since it is applied on the diffuser surface, which is the front side, the directivity and diffusion function of the pearl pigment is lost, and it cannot fulfill its original function as a semi-transparent reflector, making it impossible to obtain a clear multicolor display. cause problems.

In addition, when a light guide plate is used without using the transflective plate 9, although there is no light attenuation effect of the transflective plate 9, when it is desired to display the color filter 6 brighter, the light amount of the light source 10, such as the wattage Although it has been proposed to increase the temperature, the temperature rise due to heat generation is significant, and the characteristics of the liquid crystal display element 1 itself are adversely affected.

[Means to solve the problem]

The present invention minimizes light attenuation during illumination and obtains a clear multicolor illumination display.The present invention uses a light guide plate, forms a recess on the light irradiation surface of the light guide plate, and fills the recess with a predetermined synthetic resin. A color board consisting of

[Effect]

The color plate disposed in the concave portion can take in the irradiated light from the light guide plate even from the end of the color plate, so that a large area for taking in light can be obtained, and clear illumination can be achieved.

〔Example〕

Embodiments of the present invention will be described in detail below based on the accompanying drawings.

In FIGS. 2 and 3, locking recesses for fixing transflective plates of different colors are formed on the light irradiation surface of the illumination light guide plate.

The liquid crystal display element 11 is configured as a TN type cell, which has polarizing plates on both sides of which the light absorption axes are parallel to each other, and enters a transmissive state by applying a voltage to the counter electrode part 12, which serves as a display part. A front panel 14 is disposed in front of the liquid crystal display element 11 and has display windows 13 through which the electrode section 12 can be seen. An illumination light guide plate 15 is arranged behind the liquid crystal display element 11.
A plurality of locking recesses 16 are formed on the light irradiation surface of the light guide plate 15 and at positions corresponding to at least a portion of the display section formed by the electrode section 12 of the liquid crystal display element 11. Each transflective plate 17
are colored to correspond to each display section, and are formed in a shape corresponding to each of the locking recesses 16. As shown in FIG. 4, the semi-transmissive reflective plate 17 is made of a synthetic resin flat plate molded containing a pigment, for example, a pearl pigment 19 that obtains directionality on one side of a color transparent thin plate 18 such as acrylic, and a thin film. It is laminated and printed with a white paint 20 that provides a semi-transparent function, and is configured as a diffusing surface with a slightly roughened opposing surface.
A light source 21 is placed opposite to the end of the light guide plate 15, and enables uniform illumination from behind the liquid crystal display element 11 by introducing and reflecting the irradiated light beam.

In the above configuration, the assembly for performing multicolor display is simply done by simply
This can be achieved by setting it to 6. That is, the transflective plates 17 colored corresponding to each display part of the liquid crystal display element 11 are respectively locked in the corresponding locking recesses 16 of the light guide plate 15, and together with the light guide plate 15, semi-transparent color irradiation is performed. form a section. Liquid crystal display element 11
is fixed above this, and the color tone of the semi-transparent reflector 17 located at the rear is revealed through open viewing by selectively applying a voltage to the electrode section 12.

Next, the operation and effect will be explained using FIG. 5. Transflective plate 1 set in locking recess 16
7, it is possible to take in not only the irradiated light from the surface printed with the pearl pigment 19 and the white print 20, but also the irradiated light from the end of the transflective plate 17. The irradiated light taken in from the end is reflected and refracted within the color transparent thin plate 18, and is reflected by the pearl pigment 19 and white paint 20 printed on the back so that it is irradiated in the display direction.

That is, the irradiated light taken in from the end of the transflective plate 17 is reflected in the display direction without being attenuated by the pearl pigment 19 or the like, so that a color display can be performed on the color transparent thin plate 18.
Therefore, in addition to the light irradiated only from behind the conventional transflective plate 17, it is also possible to take in the irradiation light from the edge, increasing the overall light amount. It can brightly illuminate 18 different tones, making extremely efficient lighting possible.

The next embodiment attempts to carry out the above embodiment using only the irradiation light from the light guide plate.

This embodiment has almost the same configuration as the above embodiment. The difference is that all the irradiation light is provided by the light from the light source 21, so there is no need to use external light for illumination, and a pearl pigment 1 is placed on the back of the color transparent thin plate 18.
9 and white paint 20, which have reflective, directional, and diffusive effects, are no longer needed.

The color plate set in the locking recess 16 formed in the light guide plate 15 does not need to have the above-mentioned effect, so the color transparent thin plate 18 without the printing process is sufficient, and this color transparent thin plate 18 is usually A transparent thin plate with color printing can also be used instead.

The light irradiated by the light guide plate 15 is transmitted to the color transparent thin plate 1.
Since the irradiation light can be taken in from all surfaces other than the display surface of 8, the irradiation light at the color filter 6 provided in contact with the light irradiation surface of the light guide plate that does not form the conventional locking recess 16 is different from the light irradiation surface. Compared to the amount of light that can only be taken in through the contact surface between the surface and the color filter 6, the amount of light is significantly increased, that is, the color tone of the color transparent thin plate 18 can be brightly illuminated.

Further, if printing is performed on a normal transparent thin plate, it is not necessary to form each color plate individually. For example, multi-color printing is performed on the necessary parts of an acrylic board and the shapes are cut out. In order to prevent the color plates formed at this time from falling apart, the connecting arms that connect the color plates are also cut out at the same time. In addition to the locking recess for setting the color plate, the light guide plate is provided with a locking recess for setting the connecting arm. With this configuration, assembly is easy because the color plates can be set in one time without having to set them one by one into the locking recesses. That is, the lighting efficiency can be increased while maintaining the ease of assembly of the conventional color filter 6.

As an additional effect, since the color plate is disposed within the light guide plate, the thickness of the color filter, which would conventionally be laminated on the light guide plate, can be made thinner, allowing for a more compact configuration.

〔Effect of the invention〕

As explained above, in the liquid crystal display device according to the present invention, a concave portion is formed in the light irradiation surface of the light guide plate, and a semi-transparent reflective plate, a transparent thin plate printed in color, or a color plate containing pigment is formed in the concave portion. By setting a color plate made of synthetic resin such as a transparent thin plate, the irradiated light from the light guide plate can be taken in from the edge of the color plate, so the light intake area of the color plate can be widened, making it clear and efficient. You can get lighting effects.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view showing the conventional structure of a liquid crystal display device for multicolor display, FIG. 2 is an exploded perspective view showing an embodiment of the liquid crystal display device according to the present invention, and FIG. FIG. 4 is an enlarged sectional view of a transflective plate used in the present invention, and FIG. 5 is a diagram showing the operation of the present invention. Liquid crystal display device: 11, counter electrode: 12, display window: 13, front panel: 14, light guide plate: 1
5. Concave part: 16, Transflective plate (color plate): 1
7. Color transparent thin plate (color plate): 18, pearl pigment: 19, white paint: 20.

Claims (1)

[Scope of Claims] 1. A liquid crystal display element whose display portion is formed of an electrode pattern, a light guide plate disposed behind the liquid crystal display element, and a light source for illumination disposed at the end of the light guide plate; In a liquid crystal display device comprising a transparent color plate disposed on a light irradiation surface of a light guide plate at a position corresponding to at least a part of the display section, the color plate is formed by containing a dye. or a synthetic resin plate printed in color on the surface thereof, wherein the color plate is disposed in a recess formed in the light irradiation surface of the light guide plate. Display device. 2. In the color plate according to claim 1, the color plate is a transflective plate that can reflect light emitted from the display direction and transmit light emitted from the light source in the display direction. A color board that is characterized by certain things.