JPH02131284A - Extremely thin display device - Google Patents

Abstract

PURPOSE:To obtain a uniform and bright plane light source and to realize an extremely thin type by providing an AC power source which is connected to a transparent common electrode present at the boarder of a two-layer type EL plane light source. CONSTITUTION:This device is equipped with the two-layered EL (electroluminescence) plane light source consisting of a 1st plane light emission layer 12 which emits the 1st color of primary-color light emission and a 2nd plane light emission layer 13 formed of longitudinal and lateral stripes of two kinds of light emitting materials of the 2nd and 3rd colors of the three primary color light emission. Further, a matrix drive type liquid crystal panel 1 which has a mosaic color filter matching the strips pitch of the 2nd plane light emission layer 3 and the AC power source 17 connected to the transparent common electrode 15 present at the boarder of the two-layer type EL plane light source are provided on the front surface of the two-layer type EL plane light source. Consequently, the EL light emission layers which are formed uniformly are used and the primary color light emission is separated into the two layers to increase the quantity of light emission, so the bright and thin type three-wavelength white light source is obtained.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a display device capable of full-color display that can be used for video and information equipment, etc., and is effective for ultra-thin display devices using special K liquid crystal panels. It is something.

2. Description of the Related Art Conventional color liquid crystal display devices using fluorescent lamps as backlights have been developed.

That is, since liquid crystal panels are not self-luminous devices, most of them are used as a border for controlling the amount of transmitted light. There are some types of flat light for monochrome display LCD panels that use distributed ICL as a surface light source.
A white ICL light emitting surface that emits three wavelengths for color display has poor luminous efficiency and is not practical.

FIG. 6 shows a configuration diagram of a color liquid crystal display device using a fluorescent lamp, in which 1 is a liquid crystal panel, 2 is a glass 7 substrate on which a color filter 10 and transparent electrodes 6 are formed, The liquid crystal material 4 is held between the glass substrate 3 on which the other electrode pattern 6 is formed. Reference numeral 7 denotes a diffuser plate that makes the light uniform, and a light source composed of a fluorescent lamp 8 and a reflector plate 9 is arranged behind the liquid crystal panel 1. Note that there are various structures for the liquid crystal panel 1.
In those using Tsinutnemati Sok (TN) i crystal, it is necessary to arrange a polarization filter outside the glass substrate 2.3, and the liquid crystal material 4 is generally sandwiched between alignment films.

In the conventional liquid crystal display device configured as described above,
A diffuser plate 7 serves as a surface light source for light transmitted through the liquid crystal panel 1.
Uniform light emission characteristics are obtained by using . Generally, the fluorescent lamps 8 are rod-shaped and arranged at a certain distance. The light beams emitted from the lamps 8 directly reach the diffuser plate 7K, and the light beams reflected by the reflector plate 9 to increase brightness overlap, and the liquid crystal panel 1K is irradiated with the light beams.

Problems to be Solved by the Invention However, in the above configuration, since the fluorescent lamp 8 is a rod-shaped light source, there is a problem that the thickness direction becomes large when trying to obtain uniform brightness on the surface of the diffuser plate 7. had. In addition, the brightness did not increase much because of the diffuser plate 7.

In view of this point K, an object of the present invention is to provide an ultra-thin display device that has a uniform bright surface light source, can realize an ultra-thin design, and is capable of color display.

Means for Solving the Problems The present invention provides a first planar light-emitting layer that emits the first color of the three primary colors, and two types of light-emitting materials that emit the second and third colors of the three primary colors, vertically or A two-layer EL (abbreviation for electroluminescence) surface light source consisting of a second planar light-emitting layer formed in the shape of seven horizontal stripes, and a second planar light-emitting layer in front of the two-layer EL surface light source. An ultra-thin display comprising a matrix-driven liquid crystal panel having a mosaic color filter that matches the 7-tribe layer, and an AC power supply connected to a transparent common electrode located at the boundary of the two-layer EL surface light source. It is a device.

Function The present invention uses a uniformly formed EL light emitting layer according to the above-described structure, and also uses a bright and thin three-wavelength white light source in order to separate the three primary colors into two layers and increase the amount of light emitted. Can be configured.

Embodiment FIG. 1 shows a configuration diagram of an ultra-thin display device in a first embodiment of the present invention. In FIG. 1, 1 is a liquid crystal display panel, which functions in the same way as the conventional example. Descriptions of parts with the same symbols are omitted (see Figure 6). 11 is a glass substrate forming a two-layer EL, 12 is a first light-emitting layer, and 13 is a second light-emitting layer, in which two types of light-emitting materials are formed into a nutripe-like film. Both luminescent layers 12, 13 are sandwiched by a common transparent electrode 16 and respective opposing surface electrodes 14 and 16K. 1 is an AC power source that applies an AC voltage to both light emitting layers.

The operation of the ultra-thin display device of this embodiment configured as described above will be described below. In order to clarify the operation, FIG. 3 shows the principle of operation of the main components when FIG. 1 is viewed from the front. 12 is a first light-emitting layer that forms green among the three primary colors; blue and red light-emitting materials are formed in the second light-emitting layer; and the color filter 10 of the matrix-driven liquid crystal panel has four They are arranged in a field shape, making up one set. In this case, the second planar light-emitting layer 13 is formed in a nutripe (horizontal stripe) shape in accordance with the arrangement of the color filter 1o in the X direction. The liquid crystal panel 1 performs line-sequential scanning drive, and has an X driver circuit 21 and a Y driver circuit 21.
The driver circuit 20 is operated by matori-1 drive. Typical driving methods for liquid crystal pixels arranged in matrix are well known and will not be described here. Part 3 about the light emitting operation of the two-layer ICL surface light source, which is important in the present invention.
The operation will be explained using figures. As is well known, in EL light emission, when an electric field is applied to a transparent electrode, surface light is emitted. However, when multiple layers are used, the colors of the emitted light are additively mixed, and the green light of the first light emitting layer 12 is different from that of the second light emitting layer. The light passes through the layers and passes only through the green filter location of the color filter 1o, and is obtained as light output. Similarly, the red and blue emitted light passes only through the red and blue filters of the color filter 10 and is obtained as optical output. As described above, the color filter 10 operates as if there were a white light source on the rear surface, but in order to increase the luminance, the frequency of the AC power source 17 is changed as shown in FIG. 4 (4-e). It is driven at a frequency N times the vertical drive frequency of the display panel 1 to obtain high brightness. In the case of the light emission of the picture element of the color filter 10 of (X3"5) shown by K in FIG. 3, the vD of (4-1)
When PALNU is applied, the X driver circuit outputs X, . X2.
Generate line sequential scanning PALNU every line period as X5..., Y, if there is a bright signal (4-5)K
As shown, a voltage is applied to the liquid crystal to allow the amount of light to pass through.

The light emitting pulse emits KN times as shown in (4-7)K.
: (XS-Y5) (7) In response to the signal (+-
8) Red light will be passed through as shown in the o waveform.

As described above, according to the present example, by adding the emitted light colors of the two-layer EL, it is possible to obtain a display device in which a very bright and very thin surface light source is arranged. Dispersed type E, which is close to white, is used for conventional monochrome LCD displays.
Although there are display devices using L single-layer type surface light sources, it is difficult to obtain high luminance of three-wavelength white light suitable for color display. In the present invention, a thin surface light source with good color reproduction is realized by using thin AC type EL light emitting light and using two layers.

In general, thin-film AC type EL can be used as a display device by itself because it can obtain high brightness.Although it is possible to drive IJ sokunu, the driving voltage is high and ICs packed in high density are required.
This makes conut very expensive and the brightness is 2of-
The limit is around L. On the other hand, in this example, the color EL light emitting layer is not driven in a matrix but is driven in a simple planar manner, and the light emission frequency is increased by N times, thereby making use of the brightness increase in proportion to the frequency, which is a characteristic of the light emission characteristics of EL. . Therefore, if N=about 100, a surface light source of about 10oOft-L can be realized, and a brightness comparable to that of a fluorescent lamp can be obtained.

Moreover, it is possible to obtain an ideal surface light source with far better uniformity than in the past.

FIG. 2 is a block diagram of an ultra-thin display device showing a second practical example of the present invention. In the figure, 1 is a liquid crystal display panel whose glass substrate 13 is also used as a glass substrate forming an EL light emitting layer. The LCD will be in Guest Honuto mode.

By configuring as shown in mJ, an even thinner display device can be realized. Moreover, the nutripe-like formation of the second light-emitting layer can be easily matched with the arrangement of the color filter 10 of the liquid crystal display panel, and can be manufactured with high precision.

In Figure 3, the first light-emitting layer was selected to be green, but in this case, a green filter with high visibility is used for the four picture elements.
Since there are two, it is easy to obtain horizontal resolution. As another method, in FIG. 3, if the first light emitting layer is selected from among the EL light emitting materials, a material with the lowest luminous efficiency, such as blue, has the effect of making it easier to obtain a white paramme.

Further, in this embodiment, a liquid crystal display panel with a color filter is used as a matrix drive type panel, but any other transmissive display panel using a modulation element may be used.

Effects of the Invention As explained above, according to the present invention, an ultra-thin color display device can be realized, and its practical effects are significant.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an ultra-thin display device according to one embodiment of the present invention, FIG. 2 is a block diagram of an ultra-thin display device according to another embodiment of the present invention, and FIG. 3 is a diagram of the principle of operation. FIG. 4 is an operating waveform diagram, and FIG. 6 is a configuration diagram of a conventional display device. 1...H crystal display panel, 10...Color filter 5 filter, 2...First planar light emitting layer,...Second planar light emitting layer , 7... AC power supply.

Claims (5)

[Claims] (1) A first planar light-emitting layer that emits the first color of the three primary colors, and a second planar light-emitting layer that is formed in vertical or horizontal stripes using two types of light-emitting materials that emit the second and third colors of the three primary colors. a two-layer EL surface light source comprising two planar light-emitting layers; and a matrix drive having a mosaic color filter on the front surface of the two-layer EL surface light source that matches the stripe pitch of the second planar light-emitting layer. 1. An ultra-thin display device comprising: a 2-layer type liquid crystal panel; and an AC power source connected to a transparent common electrode located at the boundary of the two-layer EL surface light source. (2) The ultra-thin display device according to claim 1, wherein the AC power source has a frequency N times the frame frequency. (3) The ultra-thin display device according to claim 1 or 2, characterized in that the first planar light-emitting layer emits light in green color, and the second planar light-emitting layer lights in red and blue. . (4) The ultra-thin display device according to claim 1 or 2, wherein the luminescent color of the first planar luminescent layer is made of a luminescent material with the lowest luminous efficiency among the three primary colors. (5) A claim characterized in that the glass substrate of the two-layer EL surface light source and one glass substrate of the matrix-driven liquid crystal panel are shared by one glass substrate, and the liquid crystal panel uses a guest host liquid crystal. The ultra-thin display device according to item 1, 2, 3 or 4.