JPH10282494A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device provided with an organic EL surface light emitting panel capable of obtaining white light having high intrasurface uniformity and executing highly efficient light emission and having color display performance. SOLUTION: An organic EL element 15 for executing blue surface light emission is formed on the back of a transparent substrate 14 and a white light synthetic layer 16 consisting of a set of fine blue/red PL parts 16R, blue/green PL parts 16G and blue/blue PL parts 16B is arranged in the front of the substrate 14. Blue light is absorbed by the layer 16, light elements of R, G and B are emitted and these light elements constitute white light by additive color mixture, so that the white light can be supplied to a liquid crystal display panel 13 as illumination light. Thereby fine white display light based on uniform surface light emission can be made incident on the panel 13 and color display having high display performance can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a display device, and more particularly, to a liquid crystal display device having an electroluminescent element which emits surface light as a backlight.

[0002]

2. Description of the Related Art As a conventional liquid crystal display device, for example, one having a configuration as shown in FIG. 9 is known. As shown in FIG. 1, the liquid crystal display device 101 includes a liquid crystal display panel 1.
02 and a backlight system 103. The liquid crystal display panel 102 has a front transparent substrate 104 and a rear transparent substrate 105. R, G, B color filters 106R, 10R in a predetermined arrangement are provided on the surface of the front transparent substrate 104 on the side facing the rear transparent substrate 105, that is, on the opposite inner side surface.
6G and 106B are formed. Further, a black mask 107 is formed between the color filters 106R, 106G, and 106B. Further, the color filters 106R, 106G, 106B and the black mask 107 are covered with a protective film 108. A plurality of front liquid crystal drive electrodes 109, which are formed in parallel and form a stripe, are formed on the opposing inner side surfaces of the protective film 108. These front liquid crystal drive electrodes 109 and the protective film 1 are formed.
08, a pre-alignment film 110 is formed. On the other hand, on the opposite inner side surface of the rear transparent substrate 105, a plurality of rear liquid crystal driving electrodes 111 formed in parallel with each other in a direction intersecting with the above-described front liquid crystal driving electrode 109 are arranged. The front liquid crystal drive electrode 109 and the rear liquid crystal drive electrode 11
1 intersects with each of the color filters 10 described above.
6R, 106G, and 106B are set. Further, the rear transparent substrate 105 and the rear liquid crystal drive electrode 1
11 is covered with the post-alignment film 112. Then, the front transparent substrate 104 and the rear transparent substrate 105 are bonded together via a sealing material (not shown) such that the respective alignment films 110 and 112 face each other, and are formed by both the alignment films 110 and 112 and the sealing material. Liquid crystal 113 is sealed in the gap. Further, a front polarizer 114 is disposed on an outer side surface (front surface) of the front transparent substrate 104 facing the front transparent substrate 104.
A rear polarizing plate 115 is disposed on the outer side surface (rear surface) of the optical disk. A backlight system 103 is disposed behind the liquid crystal display panel 102 having such a configuration. The backlight system 103 includes a cold cathode tube 116, a light guide plate 117, a reflection plate, a diffusion plate, and the like.

In a conventional liquid crystal display device having such a configuration, light from a backlight system 103 is transmitted or cut off in accordance with a modulated state of liquid crystal of a liquid crystal display panel 102, so that a liquid crystal display is provided. Becomes possible.
In each pixel portion, each color filter 10
Since the light separated according to the action of 6R, 106G, and 106B is emitted, color display is possible.

[0004]

However, in the above-mentioned conventional liquid crystal display device, the backlight system 10
3, it was difficult to obtain uniform surface light emission. This is because the cold cathode tube 116, which is the light source of the backlight system 103, is linear or U-shaped, and the light from this light source is guided by the light guide plate 117, This is because it is difficult to make a panel that performs efficient and uniform surface emission by using the reflection function, the scattering function of the diffusion plate, and the like.

As a countermeasure against such a problem of the backlight system, studies have been made to use a (dispersion type) inorganic EL (electroluminescence) panel which is a surface-emitting panel in the backlight system. However, the inorganic EL panel has a problem that sufficient luminance cannot be obtained and the light emission life is short. In particular, the inorganic EL panel has a problem that it is difficult to obtain white light emission, and even if it can be obtained, the light emission efficiency is low. For this reason, inorganic EL
It is considered difficult to practically use the panel as a backlight.

Recently, the use of an organic EL panel which emits light at high luminance with a lower applied voltage than an inorganic EL element has been studied as a surface emitting panel. However, organic EL
Even if a panel is used, it is considered that it is difficult in principle to realize white light, which is required as a backlight of a color display, at a high luminous efficiency at an element level.
That is, when an attempt is made to obtain white light by dispersing a fluorescent dye or the like in an organic light emitting layer of an organic EL panel, white light is efficiently generated due to energy transition between adjacent molecules or thermal loss due to stepwise deactivation. It becomes difficult.

One problem to be solved by the present invention is:
What measures should be taken to obtain a liquid crystal display device capable of performing good color display with a backlight system that emits light with high in-plane uniformity and high efficiency of white light emission? On the point. Another problem to be solved by the present invention is that what kind of means should be taken to obtain a liquid crystal display device that enables color display with high luminous efficiency and can reduce power consumption? It is in the point.

[0008]

According to the first aspect of the present invention,
In a liquid crystal display device, an organic EL element that performs surface emission corresponding to a display area of the liquid crystal display panel is provided behind the liquid crystal display panel, and the organic EL element is provided between the liquid crystal display panel and the organic EL element. It is characterized in that a plurality of photoluminescence means for absorbing light in the wavelength range of light generated by the EL element and generating light in mutually different wavelength ranges are arranged.

According to the first aspect of the present invention, light generated by the organic EL element is absorbed by the photoluminescence means,
Each photoluminescence means generates light in a specific wavelength range. The light generated by the plurality of photoluminescence means enters a liquid crystal display panel and becomes display light. By adopting such a configuration, light of the same color is uniformly generated in the plane of the organic EL element, and the photoluminescence means that absorbs this light generates light of different wavelength ranges. It is possible to perform color display on the panel side. In addition, by using the photoluminescence means, it is possible to emit light with high energy efficiency using light generated by the organic EL element, and a liquid crystal display with high display luminance can be realized.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of a liquid crystal display device according to the present invention will be described below based on embodiments shown in the drawings. (Embodiment 1) FIG. 1 is a sectional view showing Embodiment 1 of a liquid crystal display device according to the present invention. In the figure, reference numeral 11 denotes a liquid crystal display device. The liquid crystal display device 11 is composed of an organic EL surface light emitting panel 12 and a liquid crystal display panel 13 as shown in FIG.

First, the configuration of the organic EL surface light emitting panel 12 will be described. As shown in FIG. 1, the organic EL surface light-emitting panel 12 has a display area of a liquid crystal display panel 13 on a rear (lower side in the figure) surface (hereinafter referred to as a rear surface) of a transparent EL substrate 14 made of glass or synthetic resin. An organic EL element 15 having a corresponding light-emitting region is formed, and a white light synthesizing layer 16 as a photoluminescence (hereinafter, referred to as PL) array is provided on the front (upper side in the figure) surface (hereinafter, referred to as front side) of the transparent EL substrate 14. Are formed so as to correspond to the light emitting regions of the organic EL element 15.

The organic EL element 15 is, as shown in FIG.
On the rear surface of the transparent EL substrate 14, an anode electrode 17,
An organic EL layer 18 and a cathode electrode 19 are stacked.
The anode electrode 17 is transparent, for example, ITO (indium tint).
In oxide), it is formed so as to correspond to the display area of the liquid crystal display panel 13. The organic EL layer 18 is, for example, N, N′-di (α-naphthyl) -N, N′-diphenyl-1,1′-biphenyl-4,4 ′ in order from the anode electrode 17 side.
A hole transport layer composed of diamine (hereinafter referred to as α-NPD) and 96 wt% of 4,4′-bis (2,2′-diphenylvinylene) biphenyl (hereinafter referred to as DPVBi),
A light emitting layer comprising 4 wt% of 4'-bis (2-carbazolevinylene) biphenyl (hereinafter, referred to as BCzVBi) and an electron transporting layer comprising a tris (8-hydroxyquinoline) aluminum complex (hereinafter, referred to as Alq3). It is configured to be laminated. The organic EL layer 18 formed of such a material layer generates blue light when an electric field is applied. The light emitting area of the organic EL layer 18 is:
The setting is made so as to correspond to the display area of the liquid crystal display panel 13. Below, α-NPD, DPVBi, BCzV
The structural formulas of Bi and Alq3 are shown.

[0013]

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The cathode electrode 19 formed on the rear surface of the organic EL layer 18 is made of a metal material such as MgIn, Al
It is formed of Li or the like. This cathode electrode 19 also
It is formed so as to correspond to the display area of the liquid crystal display panel 13. Although not shown, a protective film for shielding water and oxygen is formed on the entire surface of the organic EL element 15.

Next, the configuration of the white light combining layer 16 formed on the front side of the transparent EL substrate 14 will be described. This white light combining layer 16 absorbs light in the blue wavelength range and newly generates light in the red wavelength range, and the blue / red PL section 16R absorbs light in the blue wavelength range and newly emits green light. A blue / green PL unit 16G for generating light in a wavelength range, and a blue / blue PL unit 16B for absorbing light in a blue wavelength range and generating light of a blue wavelength
Are arranged adjacent to each other in a predetermined arrangement, and the occupied area of each PL section is sufficiently small (preferably 1) in comparison with the area of one pixel of the liquid crystal display panel.
(One third or less of the pixel area). In addition, as a material constituting these PL portions,
A well-known photoluminescence material can be applied.

The structure of the organic EL surface light emitting panel 12 has been described above. Next, the liquid crystal display panel 13 will be described. In the present embodiment, a liquid crystal display panel 13 having a configuration using a simple matrix driving method is applied.

Hereinafter, a specific configuration of the liquid crystal display panel 13 of the present embodiment will be described. The liquid crystal display panel 13 of the present embodiment has a front transparent substrate 20 and a rear transparent substrate 21. R, G, and B color filters 22R, 22G, and 22 are arranged in a predetermined arrangement on the opposed inner side surface of the front transparent substrate 20.
B is formed. In addition, the color filters 22R,
A black mask 23 is formed between 2G and 22B. Further, these color filters 22R,
22G, 22B and the black mask 23 form the protective film 2
4 is covered. A plurality of front liquid crystal driving electrodes 25 are formed on the opposing inner side surfaces of the protective film 24 in parallel to form a stripe shape.
A pre-alignment film 26 is formed so as to cover. On the other hand, a plurality of rear liquid crystal driving electrodes 27 formed in parallel with each other in a direction intersecting the above-described front liquid crystal driving electrode 25 are arranged on the inner surface of the opposing rear transparent substrate 21. The area (pixel area) where the front liquid crystal drive electrode 25 and the rear liquid crystal drive electrode 27 intersect is the above-described color filter 22R,
It is set to correspond to 2G and 22B. Also,
The rear transparent substrate 21 and the rear liquid crystal drive electrode 27 are covered with a rear alignment film 28. Then, the front transparent substrate 20 and the rear transparent substrate 21 are bonded via a sealing material (not shown) such that the respective alignment films 26 and 28 face each other,
A liquid crystal 29 is sealed in a gap formed by the two alignment films 26 and 28 and the sealing material. Further, a front polarizer 30 is disposed on the opposing outer surface (front surface) of the front transparent substrate 20, and a rear polarizer 31 is disposed on the opposing outer surface (rear surface) of the rear transparent substrate 21.

Next, the liquid crystal display device 11 having such a configuration will be described.
The operation and operation of will be described. When displaying on the liquid crystal display panel 13, an electric field is applied to the liquid crystal 29 by driving the front liquid crystal driving electrode 25 and the rear liquid crystal driving electrode 27 line-sequentially, and the liquid crystal 29 is oriented to a predetermined orientation according to the strength of the electric field. It is driven so that The light emitted from the organic EL surface light-emitting panel 12 is transmitted or blocked through the pixel portion in accordance with the orientation state of the liquid crystal 29, thereby enabling display. At this time, since each pixel portion of the liquid crystal display panel 13 includes the color filters 22R, 22G, and 22B, light transmitted through the color filters emits R, G, and B colors by the spectral action of the color filters. Is emitted.

In this embodiment, when an electric field is applied between the anode electrode 17 and the cathode electrode 19 in the organic EL element 15, blue light is generated from the organic EL layer 18. The blue light passes through the transparent EL substrate 14 and enters the white light combining layer 16 because the cathode electrode 19 is a light-reflective metal material. At this time, the white light combining layer 1
6, in the blue / red PL section 16R, the organic EL element 1
The light in the blue wavelength range from No. 5 is absorbed to newly generate light in the red wavelength range. The blue / green PL unit 16G absorbs light in the blue wavelength range and newly generates light in the green wavelength range. Further, the blue / blue PL section 16B absorbs light in the blue wavelength range and generates light of a longer wavelength blue color. Also, these PL units 16R, 16G, 16B
As described above, each of the PLs is set to be sufficiently finer than the area of one pixel of the liquid crystal display panel and is arranged adjacent to each other in a predetermined arrangement. Fine R, G, B to the front of the part
Beam light is generated. These many light beams are radiatively diffused and become white light by additive color mixing. Then, in each pixel portion of the liquid crystal display panel 13 described above, this white light is transmitted or blocked according to the alignment state of the liquid crystal 29. When white light is transmitted through the pixel portion, the white light is separated by the color filter, and display light of a desired color can be obtained. With such an operation, the liquid crystal display device 11 of the present embodiment enables color display.

In general, the efficiency of the photoluminescent material is higher as the wavelength range of the absorption light serving as the excitation energy is closer to the wavelength range of the excitation light. In the present embodiment, in particular, in the present embodiment, each PL section constituting the white light synthesis layer 16 has a higher efficiency. Since it has an action of absorbing blue light, which is the light in the shortest wavelength range of visible light, and generating light in a predetermined wavelength range of a longer wavelength range, the photoluminescence efficiency of visible light is extremely high, Energy loss can be kept low. Therefore, the light emission from the organic EL element 15 can be effectively used to the maximum. Further, in the organic EL surface light-emitting panel 12, the in-plane uniformity of white light emission can be enhanced by the action of the white light combining layer 16. Furthermore, the organic EL surface light-emitting panel 12 is originally provided with the organic EL element 15 that generates blue light with high luminous efficiency. The white light synthesizing layer 16 efficiently generates new light from the blue light. Therefore, the brightness of the display light can be increased, and a display with good contrast can be performed. Further, in the present embodiment, since the organic EL element 15 which performs surface light emission is used, there is an advantage that the backlight system can be made thin. Furthermore, the organic EL element 15
Is a low-voltage DC drive, it is easy to continuously change the brightness compared to high-voltage AC-driven elements such as cold-cathode tubes and inorganic EL elements, and the desired brightness can be adjusted according to the specification environment. It has the advantage of being configurable.

(Embodiment 2) FIG. 2 is a sectional view showing Embodiment 2 of the liquid crystal display device according to the present invention, and FIG. 2 is an enlarged sectional view of the organic EL surface emitting panel 12. The liquid crystal display device 11 of the present embodiment has a configuration in which a filter array 32 is arranged on the front surface of the white light combining layer 16 in the organic EL surface light emitting panel 12 as shown in FIG. The other configuration in the present embodiment is the same as the configuration in the first embodiment.

As shown in FIGS. 2 and 3, the filter array 32 includes a red filter section 32R corresponding to the blue / red PL section 16R of the white light combining layer 16 and a green filter section corresponding to the blue / green PL section 16G. 32G and a blue filter section 32B corresponding to the blue / blue PL section 16B are arranged so as to be adjacent to each other.

As shown in FIG. 3, when an electric field is applied between the anode electrode 17 and the cathode electrode 19, the organic EL
The layer 18 emits blue light B from the surface. The blue light B enters the blue / red PL section 16R, the blue / green PL section 16G, and the blue / blue PL section 16B, and becomes red light R, green light G, and blue light B ', respectively. The light emitted from each of the PL sections has a higher color purity at each section of the filter array 32. For this reason, it is possible to generate white light with high purity by being additively mixed by each light from the filter array 32. Particularly, in the present embodiment, since good white color can be realized, the intensity balance of each color can be set by adjusting the light transmittance of each part of the filter array 32. In addition, blue
Red PL section 16R, blue / green PL section 16G, and blue / blue PL section 1
6B, a red filter part 32R, a green filter part 32G, and a blue filter part 32B are arranged, respectively.
The blue light B generated by the organic EL element 15 is applied to the blue / red PL section 1.
When the light exits from the 6R, the blue / green PL section 16G and the blue / blue PL section 16B, the blue light B can be prevented from entering the liquid crystal display panel 13 side. For this reason, even if the light emission output of the organic EL element 15 is increased, blue light B does not escape, and a favorable liquid crystal display with high luminance is enabled. In this embodiment, the blue / blue PL unit 16B
Although the blue filter unit 32B is arranged on the top,
The blue light may be directly emitted to the liquid crystal display panel 13 side without disposing the 2B or as a transparent portion.

(Embodiment 3) FIG. 4 is a sectional view showing Embodiment 3 of the liquid crystal display device according to the present invention. In the present embodiment, a diffusion plate 33 having a light transmitting property and a light diffusing property is disposed in front of the white light combining layer 16 in the organic EL surface light emitting panel 12. The other configurations in the present embodiment are the same as those in the first embodiment. In the present embodiment, the light generated in each PL section of the white light combining layer 16 is further diffused, so that uniform surface light emission can be achieved and the color purity of the additively mixed white light can be increased, thereby improving display performance. Can be improved.

(Embodiment 4) FIG. 5 is a sectional view showing Embodiment 4 of the liquid crystal display device according to the present invention. In the present embodiment, the microlens array 34 is arranged on the front surface of the white light combining layer 16 in the organic EL surface light emitting panel 12. The other configurations in the present embodiment are the same as those in the first embodiment. In the present embodiment, the light generated in each PL section of the white light combining layer 16 is condensed by the microlens array 34 and then diffused.
The effect of mixing the light emitted from the L part is enhanced, and as a result, uniform surface light emission can be achieved and the color purity of the additively mixed white light can be increased. Therefore, also in the present embodiment, the display performance of the liquid crystal display device 11 can be improved.

(Embodiment 5) FIG. 6 is a sectional view showing Embodiment 5 of the liquid crystal display device according to the present invention. The organic EL surface light-emitting panel 12 according to the present embodiment includes a transparent EL substrate 1
4 is the same as that of the first embodiment described above,
An organic EL element 15 is formed. Transparent EL substrate 14
Of the liquid crystal display panel 13, P has substantially the same area as the pixel area so as to correspond to each pixel portion (region where the front liquid crystal drive electrode and the rear liquid crystal drive electrode intersect).
An L layer is arranged and formed. As the PL layer, as shown in FIG. 6, a blue / red PL layer 35R and a blue / green PL layer 35G
And a blue / blue PL layer 35B. These PL layers correspond to each pixel of the liquid crystal display panel 13 described later,
They are formed in a predetermined arrangement.

Next, the configuration of the liquid crystal display panel 13 in this embodiment will be described. Liquid crystal display panel 1 of the present embodiment
No. 3 has no color filter. That is, a plurality of front liquid crystal drive electrodes 25 are formed in a stripe shape on the rear surface of the front transparent substrate 20. A black mask 23 is formed between these front liquid crystal drive electrodes 25.
A front alignment film 26 is formed on the rear surface (the inner surface facing the front) of the front liquid crystal drive electrode 25 and the black mask 23. The other configuration of the liquid crystal display panel 13 is the same as that of the first embodiment.

The operation and operation of the liquid crystal display device 11 of the present embodiment will be described. First, when a DC voltage or a pulse waveform voltage is applied between the anode electrode 17 and the cathode electrode 19 of the organic EL element 15, blue light is generated from the organic EL layer 18. The blue light is applied to the blue / red PL layer 35R, the blue / green PL layer 35G, and the blue / blue PL layer 35, respectively.
At B, red light, green light and blue light are generated and emitted. The emitted light enters the liquid crystal display panel 13 and is transmitted through or shielded by the liquid crystal 29 according to the alignment state of the liquid crystal 29 in each pixel portion. The brightness of the transmitted light of each color is adjusted according to the alignment state of the liquid crystal 29. And
By performing pixel selection on the liquid crystal display panel 13, color display can be freely performed.

In this embodiment, the color liquid crystal display panel 13 is provided with a PL layer which emits a color corresponding to the display color of each pixel in each pixel, so that the non-display area covered by the black mask 23 is provided. Multicolor display can be performed without using a color filter without emitting light, and the luminance of the luminescent color of the PL layer is higher than that of a liquid crystal display device that absorbs and disperses white including each display color and displays multicolor. , The ratio of the luminance of the light to be displayed is high, and the light transmission efficiency can be greatly improved. In addition, since the organic EL surface light-emitting panel 12 uses the organic EL element 15 that emits blue light with high efficiency and uses the PL layer with high photoluminescence efficiency to realize R, G, and B light, the liquid crystal display Device 11
As a whole, the light use efficiency can be greatly increased. In addition, by increasing the light use efficiency in this way,
There is an advantage that power consumption can be reduced.

(Embodiment 6) FIG. 7 is a sectional view showing Embodiment 6 of the liquid crystal display device according to the present invention. In the present embodiment, on the front surface of each of the PL layers 35R, 35G, and 35B of the organic EL surface light-emitting panel 13 of Embodiment 5 described above, in order to increase the color purity of light generated and emitted from each PL layer. , A red filter layer 36R, a green filter layer 36G, and a blue filter layer 36B are arranged so as to correspond to each other. Other configurations in the present embodiment are the same as those in the above-described fifth embodiment.

In this embodiment, the organic EL element 15
The blue light generated in the blue / red PL layer 35R and the blue / green PL
When the light exits from the layer 35G and the blue / blue PL layer 35B or when the emission wavelength range of each of the PL layers 35R, 35G, and 35B is broad, the light emitted from the filter layer disposed on the PL layer by modulation. The liquid crystal display panel 13 is set so as to be able to increase the color purity of light incident on each pixel portion of the liquid crystal display panel 13 because it has an action of absorbing components other than the above or an action of emitting light in a wavelength region of a sharp peak. . Further, even if the emission intensity of the organic EL element 15 is set to be high, the escape of blue light can be prevented, so that high-luminance display can be performed.

(Embodiment 7) FIG. 8 is a sectional view showing a liquid crystal display device according to Embodiment 7 of the present invention. In the present embodiment, a thin film transistor 42 having a semiconductor layer made of a-Si connected to each rear liquid crystal drive electrode 27 of the liquid crystal display device 11 of Embodiment 5 described above, and each PL layer of the organic EL surface emitting panel 13 The configuration is such that a black mask 41 is provided between 35R, 35G, and 35B to shield light emitted from the PL layer from the thin film transistor. Other configurations in the present embodiment are the same as those in the above-described fifth embodiment. In the seventh embodiment, since the external light can be shielded by the black mask 23 and the emission of the organic EL surface light-emitting panel 12 is shielded by the black mask 41, it is possible to suppress the incidence of the excitation light for generating carriers to the semiconductor layer, and the thin film transistor 42. Can be prevented from malfunctioning.

Although the first to seventh embodiments have been described above, the present invention is not limited to these embodiments.
Various changes accompanying the gist of the configuration are possible. For example, in each of the above embodiments, a hole transport layer made of α-NPD is used as the organic EL layer 18 that generates blue light,
The light emitting layer is composed of 96 wt% of DPVBi and 4 wt% of BCzVBi, and the electron transport layer of Alq3 is laminated. However, any organic EL material layer that substantially generates blue light may be used. It is not limited.
In each of the above embodiments, the blue light is converted to blue / blue PL.
The blue / blue PL section 16B and the blue / blue PL layer 35B are used as long as the blue light emitted from the organic EL layer 18 has an appropriate wavelength range as the display light. Of course, the layer 35B may be omitted.

In each of the above embodiments, each PL section is disposed on the front side of the transparent EL substrate 14 and the organic EL element 15 is formed on the rear side. It is, of course, possible to adopt a configuration in which the organic EL element 15 is formed and each PL section is disposed on the organic EL element 15. Further, a protective film may be formed on the white light combining layer 16.

Further, in each of the above embodiments,
Although the organic EL layer 18 is configured to generate blue light, the organic EL layer 18 may be formed of a material that generates and emits light of another wavelength range, for example, ultraviolet light, blue-violet light, or the like. In this case, PL
What is necessary is just to set so that a part and a PL layer may modulate these source lights into R, G, B light, for example.

Further, in each of the above-described embodiments, the liquid crystal display panel 13 is configured by simple matrix driving. However, it is needless to say that the liquid crystal display panel 13 may be configured by an active driving system including a pixel electrode and a thin film transistor as a switching element. In addition, it is of course possible to appropriately change the liquid crystal display mode, and the presence or absence of the polarizing plate is appropriately changed according to the liquid crystal display mode. In particular, in a liquid crystal mode such as PDLC, a high-luminance display can be performed because the liquid crystal mode functions as an optical shutter without a polarizing plate. Further, in each of the above-described embodiments, the PL section and the PL layer are formed of organic E
Although provided on the L-surface light-emitting panel 12 side, it is of course possible to adopt a configuration provided on the liquid crystal display panel 13 side. The above-mentioned liquid crystal display device is of a reflective type at the time of light and emits external light to the cathode electrode 19.
It is also possible to make it possible to select the display so that the organic EL surface light-emitting panel 12 emits light and displays the light when the light is reflected, and in the dark, it is of a transmissive type.

[0037]

As is apparent from the above description, according to the present invention, a good color display is provided by providing a backlight system which has high in-plane uniformity of white light emission and emits light with high efficiency. There is an effect of realizing a liquid crystal display device that can perform the above. Further, according to the present invention, there is an effect that a liquid crystal display device capable of performing color display with high luminous efficiency and reducing power consumption is realized.

[Brief description of the drawings]

FIG. 1 is a sectional view showing Embodiment 1 of a liquid crystal display device according to the present invention.

FIG. 2 is a sectional view showing Embodiment 2 of the liquid crystal display device according to the present invention.

FIG. 3 is an enlarged sectional view of the second embodiment.

FIG. 4 is a sectional view showing Embodiment 3 of the liquid crystal display device according to the present invention.

FIG. 5 is a sectional view showing Embodiment 4 of the liquid crystal display device according to the present invention.

FIG. 6 is a sectional view showing Embodiment 5 of the liquid crystal display device according to the present invention.

FIG. 7 is a sectional view showing Embodiment 6 of the liquid crystal display device according to the present invention.

FIG. 8 is a sectional view showing Embodiment 7 of the liquid crystal display device according to the present invention.

FIG. 9 is a cross-sectional view illustrating a conventional liquid crystal display device.

[Explanation of symbols]

 Reference Signs List 11 liquid crystal display device 12 organic EL surface emitting panel 13 liquid crystal display panel 15 organic EL element 16 white light synthesis layer 16R blue / red PL section 16G blue / green PL section 16B blue / blue PL section 32 filter array 33 diffusion plate 34 micro lens array 35R Blue / red PL layer 35G Blue / green PL layer 35B Blue / blue PL layer

Claims (3)

[Claims] 1. An organic EL element which performs surface light emission corresponding to a display area of the liquid crystal display panel is provided behind the liquid crystal display panel, and the liquid crystal display panel and the organic EL element are provided.
A liquid crystal, wherein a plurality of photoluminescence means for absorbing light in the wavelength range of light generated by the organic EL element and generating light in different wavelength ranges from each other are arranged between the liquid crystal display and the element. Display device. 2. The liquid crystal display device according to claim 1, wherein a predetermined color filter is provided for each pixel of the liquid crystal display panel. 3. The photoluminescence means comprises: blue / red photoluminescence means for absorbing blue light to generate red light; blue / green photoluminescence means for absorbing blue light to generate green light; Blue-blue photoluminescence means for absorbing light to generate blue light,
2. The liquid crystal display device according to claim 1, wherein there are three types.