JPH0614247B2 - Emissive display device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-cost light emitting display device which is particularly excellent in contrast and viewing angle characteristics.

Conventional technology Currently, word processors, personal computers, televisions, CAD /
The display devices used in CAM and the like are mainly those using a CRT (cathode ray tube), and from one that can display A4 full pages to one that can display high quality full color, one size is available. 0.5 ″
Various types up to about 40 "are used for office work or entertainment. However, the CRT has a large volume, and it is difficult to make it thin, and high voltage is required. There is a strong demand for large capacity, low cost full color display devices.

Conventional flat panel color display devices include plasma displays, flat CRTs, fluorescent display tubes, etc., which are still under development, and liquid crystal pocket televisions, which have already been commercialized. The former three have problems that the light emission efficiency is low at present, the panel structure is complicated and expensive, and it is difficult to increase the size. On the other hand, liquid crystal full-color display devices are being actively developed toward full-color enlargement because of the ease of upsizing. As an example, it is described in Technical Report of the Institute of Television Engineers of Japan, Vol. 8, No. 4, pp. 1 to 6, 1984. In order to realize full-color display with liquid crystal, the liquid crystal is usually used as a light valve for panchromatic light, and color filters are added by mixing colors on a two-dimensional surface by providing red, green, and blue color filters in strips or dots. The image is displayed.

Twisted nematic type (hereinafter abbreviated as TN) is shown in Fig. 4.
The configuration and operation of a conventional full-color panel using the liquid crystal display mode will be described. The TN type full-color matrix panel has a pair of glass substrates 2 and 8 on which transparent row electrodes 3 and transparent column electrodes 7 made of indium oxide or the like are provided.
The nematic liquid crystal 4 having positive dielectric anisotropy is sandwiched between the glass substrates 2 and 8 and the pair of polarizing plates 1 and 9 are provided outside the glass substrates 2 and 8.

Red R, green G, and blue B color filter layers 5 for forming a color panel are respectively column electrodes (or row electrodes).
It is provided regularly on the top. Although the panel is shown in a simplified manner, an alignment treatment layer for regulating the alignment of liquid crystal molecules is usually provided on the color filter layer side surface and the row electrode side surface. On the surface, they are arranged in a specific direction almost parallel to the substrate, and the arrangement direction of molecules is different by 90 ° between one substrate and the other substrate, and the molecules are arranged from one substrate to the other substrate. The directions are gradually twisted, and in the end, an orientation treatment is applied to the surfaces of both substrates so that a twist of approximately 90 ° is generated between both substrates.

In a liquid crystal color panel, a transmissive type is usually used to obtain a bright display. That is, the white back light source 10 is provided on the back surface of the panel. When a linear light source such as a fluorescent lamp is used as the light source 10, a light diffusing plate (not shown) is provided between the light source 10 and the liquid crystal in order to obtain uniform brightness without unevenness on the two-dimensional display surface. It is provided between the panels. If the light source 10 is a planar light source such as electroluminescence, the light diffusion plate is not necessary. The above is one example of the conventional full-color liquid crystal panel, but the biggest drawbacks of the conventional technology are: (1) Generally, in a simple XY matrix display panel,
When a panel having two scanning lines is driven by a line-sequential signal, the ratio R of the effective value voltage applied between the electrodes sandwiching the pixel to be turned on and the pixel to be turned off is the so-called voltage averaging method. When the method is adopted and optimized so that R becomes maximum, R = {(N ^1/2 +1) / (N ^1/2 -1)} ^1/2 . That is, in a panel having a simple matrix structure, a crosstalk voltage is applied to off-pixels as well, resulting in a reduction in contrast. For example, in the case of N = 100 lines, R = 1.1 and only 10% of the effective value voltage applied between the electrodes corresponding to the off pixels is applied to the ON pixel, and the voltage difference of 10% is displayed. You have to add contrast. That is, the display medium used in the simple matrix panel cannot display a high contrast unless the brightness-voltage characteristic is sharp and the threshold value characteristic is clear. In the conventional TN cell, since the sharpness is insufficient, it is the actual situation that even if N = 64 (R = 1.134), the contrast is not comparable to that of the active matrix panel. On the other hand, in the TN cell, the light transmission characteristic of the cell generally depends on the light wavelength as shown in the above-mentioned reference, so-called optical rotation dispersion occurs, and the luminance-voltage characteristic varies considerably depending on the wavelength. Also, when a dielectric layer called a color filter is provided on the transparent electrode as shown in the figure, the filter layer is inserted in series with the liquid crystal, so this on and off applied between the electrodes The voltage ratio is further lowered in the liquid crystal layer, and the contrast of the color panel is considerably worse than that of the monochrome panel.

However, SBE (abbreviation of Super-Birefringence-Effect)
The mode is much sharper than the TN mode in which the brightness-voltage characteristics are twisted by 90 degrees. For example, Applied Physics Letters, Vol. 45, 1020-102.
Page 3, ('84) and SID (Society for Information Display: Socity for iformstio
n Disply), 1985 digest, 120-123
Page and British Patent GB 2143336A, JP-A-60.
-73525, etc. However, since this mode uses a birefringence mode, the wavelength dispersion is large, and the display is colored when used with white light, and it is not suitable as a monochrome light valve for white light, and of course full color display combined with R, G, B filters. Has never been tried. A cell having a twist angle of about 180 degrees is disclosed in Japanese Patent Laid-Open No.
0-196728 and 360 ° twisted cells, see Journal Applied Physics 53.
Vol., Page 8599, ('82), but the possibility of flat-panel full-color display is not mentioned.

(2) Another drawback of the conventional TN type full color display panel is that the luminous flux utilization rate from the light source 10 is low. That is, the full-color light spectrum from the light source 10 must include red, blue, and green color light components. Since light from an ordinary light source is natural light, when passing through the polarizing plate 1, about 50% of the luminous flux is absorbed by the polarizing plate and lost. Whether the display medium is liquid crystal or electro-optical crystal plate,
In a display system using a polarizing plate, this 50% light loss is inevitable whether it is a monochrome panel or a color panel. A further disadvantage of the color panel as compared with the monochrome panel is that the color filter layer 5 is inserted. That is, the polarizing plates 1 and 9 shown in FIG. 4 are assumed to be neutral polarizing plates, and the white light flux from the back light source 10 becomes white linearly polarized light by the polarizing plate 1.
This white linearly polarized light passes through the color filter layer and the liquid crystal layer 4
Whether the light enters the filter layer 5 after exiting the liquid crystal layer 4 as shown in the figure, each color filter layer absorbs light of a specific wavelength.

That is, when passing through the red filter layer, the green and blue components are
The red and green components are absorbed when passing through the blue filter layer, and the red and blue components are absorbed when passing through the green filter layer, so the original white light energy is reduced to about one-third. Will end up. If the light passing through the liquid crystal layer 4 and the color filter layer is linearly polarized light and the polarization axis thereof coincides with the polarization axis of the polarizing plate 9, there is basically no light loss when passing through the polarizing plate 9. There is no. As described above, even if the polarizing plates 1 and 9 and the color filter 5 are ideal,
Light energy passing through the color panel is almost 50% ×
33% = 16.5%. The liquid crystal panel itself usually features low voltage, low current and low power, but when it comes to liquid crystal color panels, as mentioned above, it requires a back light source and uses only part of the light flux of the back light source. Because of this, the reality is that the low power consumption of the liquid crystal is greatly impaired.

Problems to be Solved by the Invention Problems to be solved by the present invention include (1) poor threshold characteristics in a conventional TN type simple matrix panel (2) multicolor light in a conventional simple matrix panel Coloring based on (3) Full-color display that was impossible with conventional SB panels (4) Deterioration of threshold characteristics due to color filters in conventional simple matrix color panels (5) In conventional simple matrix color panels (6) It is difficult to use a plastic substrate in the conventional simple matrix panel.

In order to solve the above problems, in the light emitting display device of the present invention, the electrode surface sides of a pair of transparent substrates each having a transparent electrode are opposed to each other, and in the meantime, a voltage is applied between them. A medium whose refractive index changes is sandwiched, and a polarizing plate is provided on the outside of each transparent substrate, and a fluorescent substance layer is provided on the polarizing plate side for observing the display.
On the other polarizing plate side, a light source capable of exciting and emitting the phosphor and further a means for applying a voltage to the transparent electrode are provided, and particularly in a medium having a change in birefringence, SBE having a sharp luminance-voltage characteristic. It is equipped with a liquid crystal.

The present invention has the above-described structure, in which the SBE liquid crystal is used as a light valve, and the chromatic dispersion is prevented by using a monochromatic excitation light source, and a fluorescent substance layer having a different emission color is used without using a conventional color filter. Since the energy loss of light transmitted through the liquid crystal cell is prevented by applying different colors, a full-color image that is bright and has excellent contrast in each color can be displayed.

EXAMPLE As shown in FIG. 1, the full-color light emitting type liquid crystal display device of the present invention is basically a monochromatic excitation light source 13, a first polarizing plate 1, an SBE liquid crystal cell 14, a second polarizing plate 9, R, G, B
Of the fluorescent substance layer 11 which emits the light. In the light source 13,
Those that emit almost single wavelength light in the blue or ultraviolet range are used. As the R, G, B phosphor layer 11, one that emits light in R, G, B by excitation light from the light source 13 is used.
In the figure, what is provided in a stripe shape may of course be provided in a mosaic shape. The fluorescent substance layer 11 may be provided on the polarizing plate 9, or as shown in the figure, the one provided on the ferroelectric liquid crystal 12 transparent to visible light may be attached to the polarizing plate 9. The SBE liquid crystal cell 14 includes a pair of glasses provided with a transparent conductive film (hereinafter abbreviated as ITO) such as indium oxide, tin oxide, and a metal thin film, or between the electrode surfaces of the transparent substrates 2 and 8 made of a plastic film, The nematic liquid crystal 4 substrate with positive Δε is oriented so that it has an appropriate tilt angle, and the molecular axis is from 90 ° to 360 ° from one substrate to the other substrate. Twisted. Here, an illustration of an alignment film for aligning the liquid crystal molecules in a specific direction and having an appropriate tilt angle with respect to the electrode surface (the tilt angle of the liquid crystal molecule long axis with respect to the substrate surface) is omitted. For molecular orientation treatment, an organic thin film such as polyimide is applied to the electrode surface, dried, and then rubbed in one direction with a cloth or the like, or SiO or the like is obliquely vapor-deposited on the electrode surface, or a molecular orientation agent is applied to the substrate by dipping or the like. It is performed by adsorption.

In the present invention, the material forming the SBE cell 14, that is, the transparent substrate, the transparent electrode, the alignment film, the liquid crystal, the polarizing plate, etc., is the light source 1.
A material having a higher light transmittance than 3 is used. In the present invention, “transparent” means having high transparency to the excitation light from the light source 13.

Biphenyl-based and ester-based liquid crystals are around 30 nm around 250 nm.
Absorption is small at 0 nm or more, and phenylcyclohexane-based absorption is small at 250 nm or more.

For the polarizing plate, a uniaxially stretched oriented film such as polyvinyl alcohol (PVA) (1) a multi-halogen polarizing film in which iodine or the like is arranged, (2) a dichroic dye system in which dichroic dyes are arranged and adsorbed, (3) Polyvinylene polarization system in which metals such as Au, Ag, Hg, and Fe are arranged, PVA and polyvinyl chloride are double-bonded, and PVA is a boric acid solution containing potassium iodide and sodium thiosulfate. There is a near-ultraviolet polarizing film treated with.

Since the light transmittance T of the SBE cell strongly depends on the gap d, it is important to provide a spacer between the electrodes to keep d as constant as possible in order to obtain a uniform display. XY
In the matrix type panel, the pair of ITOs are patterned into strips, and the strips of ITO are arranged so as to be orthogonal to each other. The present invention is characterized in that the display medium uses an SBE liquid crystal mode having a sharp threshold characteristic and a color fluorescent layer is provided outside the polarizing plate instead of using a color filter. The SBE mode referred to here is a chiral nematic liquid crystal in which a small amount of chiral material is added to a nematic liquid crystal having a positive dielectric anisotropy (hereinafter abbreviated as Δε) as shown in FIG. The molecules are oriented so as to have an appropriate tilt angle, and molecules are twisted between the two substrates at an angle of 90 degrees or more and 360 degrees or less (molecular twist angle in FIG. 2), and the polarization axis of the polarizing plate 1 Is 0 with the molecular axis on the electrode 3 side
To 90 degrees (angle β in FIG. 2) other than 90 degrees, and a state of being operated in a so-called birefringence mode. An example of cell transmittance-voltage characteristics is shown in FIG. Here, φ = 240 degrees, θ = about 2 degrees, and β = 4 in FIG.
The characteristics are 5 degrees and γ = −45 degrees (each arrow direction is positive).

However, the liquid crystal cell has Δn · d = 0.65 (d = 6 μm),
The measured stretch length γ = 450 nm, which is the characteristic in the vertical direction of the panel. When the twist angle of the molecule is 90 degrees or more, the tilt angle change with respect to the voltage of the molecule located in the center of the cell becomes steep. For example, Appl. Phys. Lett. 45
Vol. 841, 1021.

The SBE mode is characterized by using this effect and the birefringence mode. As shown in FIG. 3, the brightness-voltage characteristic becomes extremely steep with respect to light of a specific wavelength. However, when the twist angle is, for example, around 90 to 200 degrees, no hysteresis appears in the luminance-voltage characteristics even if the tilt angle is small (5 degrees or less), but when the twist angle exceeds about 270 degrees, the elastic constant and pitch of the liquid crystal and the like. Generally, hysteresis is likely to occur, though it also depends on the physical property constant of. At this time, it is necessary to increase the tilt angle of the initial alignment to, for example, 20 degrees or more.

In an XY matrix type panel for displaying characters, images, etc., the pair of ITOs are patterned into strips as shown in the figure, and the strips of ITO are arranged so as to be orthogonal to each other. Thus, the intersection of both electrodes constitutes one pixel.

When the matrix panel of the present invention shown in FIG. 1 is line-sequentially driven by a normal voltage averaging method, when the number of scanning lines is N, a voltage R times as high as that of an off cell is applied to an on cell, and a pixel of both pixels is duplicated. Since the refraction properties are different, the intensity of the excitation light source passing through the second polarizing plate is different. Therefore, the emission intensity from the phosphor layer is different, and contrast is provided. What is important here is that the light rays passing through the liquid crystal layer are monochromatic in the present invention, so that TN or SB as pointed out in the reference example is used.
The optical rotatory dispersion that normally occurs in the E panel does not occur, and since there is no color filter layer on the electrodes, a net voltage R is applied to both pixels, and therefore a much better contrast than before can be obtained.

The SBE mode cell used in the present invention includes a wavelength of a light source used, a refractive index anisotropy (Δn) of liquid crystal, a pitch, a material constant such as an elastic constant, a cell gap d, a tilt angle, a polarization axis crossing angle, and a polarization. It is desirable to set the axial position so that the ratio of the transmittance of the excitation light from the light source is the largest in the on-cell and the off-cell.

In the present invention, the monochromatic light source, as well as the spectral line,
An excitation light source having a full width at half maximum that does not significantly reduce the contrast.

The fluorescent material used in the present invention may be one widely used for so-called photoluminescence such as a fluorescent lamp.
That is, Eu ³⁺ activated phosphors are typical for red light emission, and Y ₂ O ₃ : Eu ³⁺ , Y (P, V) O ₄ : Eu ³⁺ , (Y, Gd) BO ₃ : Eu ³⁺ , Y ₂ O ₂ S: Eu ^{3+ and} others 3.5MgO, 0.5MgF ₂ , GeO ₂ : Mn Tb ³⁺ activated phosphor is typical for green emission, and Y ₂ O ₂ S : Tb ³⁺ Ga ₂ O ₂ S: Tb ³⁺ Y ₂ SiO ₅ : Ce ³⁺ , Tb ³⁺ (Ce, Tb) MgAl ₁₁ O ₁₉ , LaPO ₄ : Ce ³⁺ , Tb ^{3+ and} other ZnO: Zn, ZnSiO ₄ : Mn Zn ₂ SiO ₄ : Mn LaPO ₄ : Ce ³⁺ , Tb ³⁺ Eu ²⁺ activated phosphor is typical for blue emission, and BaMg ₂ Al ₁₆ O ₂₇ : Eu ²⁺ , _{(Sr, Ca) 5 (PO} 4) 3 Cl: Eu 2+, Sr 2 P 2 O 7: Eu 2+, Ca 5 (PO 4) ^{(F, Cl): Sb 3+} (Ba, Ca, Mg) 5 (PO 4) 3 Cl: Eu 2+ Sr 5 (PO 4) 3 Cl: Eu 2+, other _{MgWO 4, CaWO 4, Sr 2} P 2 _{O 7: Sn Ca 5 (PO} 4) 3 (F, Cl): Sb 3+ Y 2 O 2 S: Tm 3+ , etc. can be utilized.

On the other hand, the light source used in the present invention must have a broad emission spectrum suitable for causing the phosphor to emit light by excitation. Further, it is desirable that the conversion efficiency from electric energy to radiant energy is as high as possible. As an example, a fluorescent lamp that utilizes the ultraviolet radiation emitted by the arc discharge in mercury vapor is suitable. A fluorescent lamp has a glass tube filled with a small amount of mercury and a few torr of odd gas such as argon, and a fluorescent substance is applied to the inner wall of the tube. A pair of electrodes is enclosed at both ends of the tube. The surface of the electrode is coated with an electron emitting substance. In a low-pressure mercury discharge lamp, about 60% of the electric energy input to the lamp has a wavelength of 254 nm.
Is converted into ultraviolet energy. 254 nm
Although it is not impossible to use directly, it is necessary to pass through the polarizing plate, transparent substrate, transparent electrode, alignment film, liquid crystal layer, etc. before exciting the phosphor layer, as is clear from FIG. Absent. Therefore, the preferable light source spectrum used in the present invention is that the energy attenuation in these layers is small, the damage to these layers is small, and the emission efficiency to the phosphor layer used is high. 313n if mercury vapor pressure is increased
Longer wavelength components such as m and 365 nm are enhanced. Alternatively, about 4 nm of ultraviolet rays with a wavelength of 254 nm generated by the discharge
You may use the fluorescent substance lamp which provided the fluorescent substance which converts into a longer wavelength light of up to 50 nm on the inner wall of a lamp tube. 450n
m is usually required as a blue light component for full color display.

If the excitation light has a wavelength in the vicinity of 450 nm, the B phosphor layer is unnecessary and a light diffusion plate may be used. Only the G and R phosphor layers 4
What efficiently emits light with excitation light of 50 nm may be used.

EFFECTS OF THE INVENTION In a conventional full-color liquid crystal panel, a TN mode liquid crystal ride valve, stripe-shaped or mosaic-shaped R,
The combination of G and B color filters and a white back light source was basic. Since the liquid crystal cell is in the TN mode and the threshold characteristic is insufficient and N becomes large, the contrast is extremely lowered, and the so-called optical rotatory dispersion in which the threshold characteristic is not uniform over all the R, G and B color lights is caused. In the simple matrix panel, the display quality is poor such as the contrast and the narrow color reproduction range and the degree of visual dependency. In order to overcome this limitation, a method called an active matrix, in which a switching element such as a TFT is provided in each pixel to improve R, has been developed and put into practical use, and it has been proved that the display quality is improved even when the TN mode is used. However, there is a drawback that the panel cost is increased. In the present invention, attention has been paid to the sharpness of the threshold characteristics of monochromatic light in the SBE mode, which was conventionally considered to be impossible for full color, and the color filter layer on the electrode, which has conventionally caused deterioration of the threshold characteristics, Get rid of,
A simple matrix panel with a large number of scanning lines N has realized high contrast and wide color reproducibility. Even if the brightness-voltage characteristic is steep and N is large, it is easy to obtain the contrast, and the excitation light transmittance of the liquid crystal panel is changed by changing the effective value voltage applied to the cell by pulse width modulation based on the normal voltage averaging method. Therefore, the intensity of the radiated light from the phosphor layer changes, and gradation display is easy, so low-cost small to meter-sized full-color TV displays and CAD terminals such as OA
It can be said that it is suitable for high-contrast color graphic display for TV.

The second feature of the present invention is the brightness of the display. That is, since R, G, B phosphor layers having different emission spectra are used instead of the conventional color filters, most of the light energy of the light source is used as the excitation energy of the R, G, B phosphors. Can be used. Therefore, if the material selection for the light source, substrate, polarizing plate, transparent electrode, and fluorescent material is optimized to minimize the absorption loss until reaching the fluorescent material, the efficiency is three times higher than the conventional one. It can be a display panel. The third feature of the present invention is that it is easy to make a lightweight and thin plastic panel. Conventionally, TN-mode plastic liquid crystal panels have been put to practical use in thin calculators and the like, but the plastic substrates that enter the inside of a pair of polarizing plates have no birefringence (optical isotropic body) or are optically uniaxial. It was necessary to use an optical axis and to align the optical axis direction with the polarization axis of the polarizing plate. Therefore, the plastics that can be used are greatly restricted, and only polyether sulfone resins, phenoxy resins, uniaxial PET (polyethylene terephthalate) resins, etc. can be used. However, in the present invention, since the light passing through the liquid crystal layer is monochromatic, the Δn · d (Δn: refractive index anisotropy, d: cell gap) of the substrate is set to the polarization axis crossing angle of both polarizing plates and the polarization. Angle of the axis with the molecular axis, Δn. In the relationship of d, the excitation light entering the polarizing plate 9 in the ON pixel and the OFF pixel both become substantially linearly polarized light, and the contrast becomes maximum if optimized so that the polarization axes of both become an angle of about 90 degrees. Even if a plastic film having an ordinary birefringence is used for the substrate, the contrast characteristic is not deteriorated and the coloring phenomenon does not occur. The use of a thin (several tens / several hundreds of microns) plastic film for the substrate is especially recommended in the present invention. Because in the panel structure of the present invention, the phosphor layer is provided on the outside of the polarizing plate, so if the substrate thickness on the front side is thicker than the size of the pixel, the color shift will occur unless the excitation light from the back light source is a parallel light beam. , The display quality is deteriorated due to color mixing.

That is, in the case of a diffusion type back light source, it is desirable to make the thickness of the front side substrate sufficiently smaller than the width of the fluorescent body, but since the monochromatic light source is used, the present invention has an advantage that the selection of the resin substrate is extremely easy. .

The fourth feature of the present invention is the expansion of the viewing angle. In the liquid crystal display, the viewing angle dependency is generally large, but this is because the equivalents Δn and d of the liquid crystal layer differ depending on the viewing direction. In the present invention, the intensity of the excitation light passing through the SBE cell has a directional property, but since the emission from the fluorescent substance stimulated by this excitation light is diffuse, the viewing angle is much wider than the conventional one. Have.

In the present invention, an example of performing full-color display has been mainly described, but it goes without saying that a monochromatic light emitting phosphor layer may be used in place of the R, G, B phosphor layer of FIG. Good. In this case, there are advantages such as improvement of contrast and expansion of viewing angle.

[Brief description of drawings]

FIG. 1 is a perspective view of a full-color display device of the present invention, FIG. 2 is a configuration diagram of an SBE liquid crystal cell, FIG. 3 is a transmittance-voltage characteristic diagram of the SBE cell, and FIG. 4 is a perspective view of a conventional full-color liquid crystal panel. It is a figure. 1 ... 1st polarizing plate, 2nd ... 1st substrate, 3 ... Transparent row electrode, 4 ... Liquid crystal layer, 7 ... Transparent column electrode, 8 ... 2nd substrate, 9 ... 2nd polarizing plate , 12 ... Third substrate, 11 ... Fluorescent material layer, 6 ... Black matrix layer, 13 ... Monochromatic excitation light source, 14 ... SBE liquid crystal cell.

Claims (10)

[Claims] 1. A pair of transparent substrates each having a transparent electrode are opposed to each other on their electrode surface sides, and a medium whose birefringence is changed by a voltage is sandwiched between the transparent substrates. A polarizing plate is provided on the outer side of each of the polarizing plates, a phosphor layer is provided on the polarizing plate side for observing the display, a light source capable of exciting and emitting the fluorescent substance on the other polarizing plate side, and a voltage is applied to each transparent electrode. A light-emitting display device, characterized in that means for applying is provided. 2. The medium is a nematic liquid crystal having a positive dielectric anisotropy, and 90% from one substrate to the other substrate.
The light emitting display device according to claim (1), wherein the light emitting display device is twisted in a range of 360 degrees to 360 degrees. 3. The light emitting display device according to claim 1, wherein the light source is a substantially monochromatic light source. 4. The light emitting display device according to claim 1, wherein the light source uses discharge of low-pressure mercury vapor. 5. A light source utilizing electroluminescence, as claimed in claim 1.
The light-emitting display device according to the item. 6. The light-emitting display device according to claim 4, wherein the light source emits light having a wavelength shorter than 450 nm. 7. The polarizing plate is any of a multi-halogen type, a dichroic dye type, a metal polarizing film type, a polyvinylene polarizing system, and a near-ultraviolet polarizing film obtained by treating PVA with a boric acid solution containing potassium iodide and sodium thiosulfate. The light-emitting display device according to claim (1), which is selected from the above. 8. The light-emitting display device according to claim 1, wherein the phosphor layers are separately coated so as to emit red, green, and blue light, respectively. 9. A display device, wherein the transparent electrodes are composed of strip-shaped transparent electrode groups, and a pair of transparent electrode groups are arranged so as to be orthogonal to each other to form an XY matrix type display panel. The light emitting display device according to claim (1). 10. The light emitting display device according to claim 1, wherein at least the substrate on the side of observing the display of the display device is made of a plastic film.