KR101073616B1 - Display device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, comprising: a light source, a color change layer that receives light from a light source to adjust transmittance, and a display including a phosphor layer that receives light transmitted through the color change layer and emits light of different wavelengths. In this case, the color change layer is changed in color according to the change of the applied electric field, thereby controlling the transmittance of the light source to drive the display element.

Unlike the liquid crystal display device which filters the light source of the backlight with the R, G, and B filter layers, the display device of the present invention emits light by directly exciting the phosphor with the backlight light source. Do not. In addition, since the process of forming the color conversion layer between the transparent electrode is simple, the manufacturing cost is low, and it is possible to drive by a variety of driving methods has the advantage that can implement excellent image quality.

Description

Display device

The present invention relates to a display device, and more particularly, to a display device capable of realizing a natural color screen by driving on / off of each of R, G, and B cells by adjusting the amount of light supplied from a backlight light source to a phosphor. It is about.

Recently, with the development of information and communication technology, development of display devices having various uses for expressing information has been made. The display device may be classified into a reflective display device, a transmissive display device, and an emissive display device according to a method of displaying light to the outside.

Cathode ray tube (CRT), which is a typical light emitting display device, has been the most widely used display device until recently due to its excellent image quality and economical efficiency due to a technology accumulated for a long time. However, since cathode ray tubes excite phosphors of specific pixels by controlling the path of electrons emitted from an electron gun, they have a limitation in reducing overall thickness. While efforts have been made to develop a flat panel display device that can compensate for the disadvantages of the cathode ray tube and achieve high quality comparable to that of the cathode ray tube, representative examples are plasma display panels (PDPs) and organic electroluminescence. Diode (Organic Light Emitting Diode, OLED).

Plasma display panels are self-luminous devices that have no limitations on viewing angle, fast response speed, and easy manufacturing processes when manufacturing large areas. However, since a high voltage is required for plasma discharge, the device has a disadvantage of low electrical efficiency, high component cost, and easy deterioration of the phosphor, which has a relatively short lifetime. Organic electroluminescent diodes also have advantages as self-luminous devices and high luminous efficiency, but have a disadvantage in that the manufacturing cost is high and the large area coping ability is low because a vacuum deposition process is essential in the manufacturing process.

Therefore, the liquid crystal display device is most widely used as a flat panel display device. Liquid crystal display (LCD) is a large-area technology derived from semiconductor technology, has high economic feasibility, and is expected to dominate the display market for a while by solving the viewing angle problem, which was a conventional problem. However, despite the technical and industrial advantages of the liquid crystal display device, the light emitting efficiency is less than 5% and the response speed of the transmissive non-light emitting display device is limited.

Various attempts have been made to improve the efficiency of such a non-luminous display device. There is a prior art for a photonic crystal display device using band gap control. The prior art is a display device using a photonic crystal with a photonic bandgap including a material having a refractive index that changes in accordance with the electric field, a reflective display according to the high reflectance of each color region of the photonic crystal or a transmissive display according to the photonic bandgap control It can be implemented as a device. However, the prior art has the same limitations as the non-emission display device as in the conventional liquid crystal display device, and in particular, since the reflection and transmission amounts must be independently controlled and adjusted in order to realize a specific color, the implementation of natural colors is complicated. Has In addition, a plurality of photonic crystals having photonic bandgaps with different reflection wavelengths must be manufactured to drive R, G, and B cells, and in this case, complexity of using different driving voltages and frequencies to drive pixels of different colors. There is a disadvantage that the color of the reflected light or transmitted light is further changed depending on the viewing angle.

Accordingly, there is a growing need for the development of a new display device capable of reducing the manufacturing cost due to the simple manufacturing process while overcoming the disadvantages of the display devices listed above.

Accordingly, a problem to be solved by the present invention is to provide a display device having a simple driving method and improved image quality, high luminous efficiency, low electric consumption, simple manufacturing process, large area, and low manufacturing cost. To provide.

The present invention, in order to achieve the above object, the color is changed by the change of the light source, the applied electric field, the color change layer for adjusting the transmittance of the light source, and the light transmitted through the color change layer to receive light of different wavelengths Provided is a display device including a phosphor layer for emitting light.

According to an embodiment of the present invention, the center wavelength of the light source is located in the range of 300 to 500 nm, and the color change layer preferably has a light absorption band in the range of 300 to 500 nm when an electric field is applied.

,

,

및

로 이루어진 군에서 선택된 적어도 하나일 수 있다.According to another embodiment of the present invention, the color changing layer is biphenyl dicarboxylic acid diethyl ester, dioctyl-substituted 2,3-di (thien-3-yl) -5, 7-di (thien-2-yl) thieno [3,4- b ] pyrazine (dioctyl-substituted 2,3-di (thien-3-yl) -5,7-di (thien-2-yl) thieno [3,4- b ] pyrazine), poly (3,4-propylenedioxythiophene) diester, poly (3,4-propylenedioxythiophene diol (poly (3 , 4-propylenedioxythiophene) diol), thiophene / EDOT / phenylene complex, poly-bithiophene, N, N-bis (4-aminophenyl) -N ', N'-di (4-methoxyphenyl) -1,4-phenylenediamine (N, N-bis (4-aminophenyl) -N ', N'-di (4-methoxylphenyl) -1,4-phenylenediamine) , Poly [N-9-heptadecanyl-2,7-carbazole-alt-5,7-di (3-octylthien-2-yl-2,3-di (thien-3-opp))- Thieno [3,4-b] pyrazine (poly [N-9-heptadecanyl-2,7-carbazole-alt-5,7-di (3-octylthien-2-yl) -2,3-di (thien -3-yl) -thieno [3,4-b] pyrazine), poly [N-9-heptadecanyl-2,7-carbazole-alt-5,7-di (3-octylthien-2-yl ) -2,3-di (fe-1-yl) -thieno [3,4-b] pyrazine (poly [N-9-heptadecanyl-2,7-carbazole-alt-5,7-di (3- octylthien-2-yl) -2,3-di (phen-1-yl) -thieno [3,4-b] pyrazine), poly [N-9-heptadecanyl-2,7-carbazole-alt- 5,7-di (3-octylthien-2-yl) 2,3-di (4-octylphen-1-yl) -thieno [3,4-b] pyrazine (poly [N-9-heptadecanyl- 2,7-carbazole-alt-5,7-di (3-octylthien-2-yl) -2,3-di (4-octylphen-1-yl) -thieno [3,4-b] pyrazine), poly (5,8-bis (2,3-dihydrothieno [3,4-b] [1,4] dioxin-5-yl) quinoxaline (poly (5,8-bis (2,3-dihydrothieno [3,4-b] [1,4] dioxin-5-yl) quinoxaline)), poly (5,8-bis (2,3-dihydrothieno [3,4-b] [1,4] Dioxin-5-yl) -2,3-di (thiophen-2-yl) quinoxaline (poly (5,8-bis (2,3-dihydrothieno [3,4-b] [1,4] dioxin -5-yl) -2,3-di (thiophen-2-yl) quinoxaline)), poly (1,4-bis (2- [3'4'-ethylenedioxy] thienyl) -2-methoxy -5-2 ''-ethylenehexyloxybenzene (poly (1,4-bis (2- [3 ', 4'-ethylenedioxy] t hienyl) -2-methoxy-5-2 ''-ethylhexyloxybenzene)), poly (3-methyl-2-{[3- (4-vinyl-benzyl) -3H-benzothiazole-2-ylidene] -hydra Zono} -2,3-dihydro-benzothiazole-6-sulfonic) acid (poly (3-methyl-2-{[3- (4-vinyl-benzyl) -3H-benzothiazol-2-ylidene]- poly (3,4-ethylenedioxythiophene) doped with hydrazono} -2,3-dihydro-benzothiazole-6-sulfonic acid),

,

,

And

It may be at least one selected from the group consisting of.

, K[(NC₅H₄CH₂PO₃H₂)RuIII(NH₃)₄(NC)RuII(CN)₅], K[(NC₅H₄PO₃H₂)RuIII(NH₃)₄(NC)RuII(CN)₅] 및 Ru(bpy)2-dioxolene 착물로 이루어진 군에서 선택된 적어도 하나일 수 있다.According to another embodiment of the present invention, the color change layer is

, K [(NC ₅ H ₄ CH ₂ PO ₃ H ₂ ) RuIII (NH ₃ ) ₄ (NC) RuII (CN) ₅ ], K [(NC ₅ H ₄ PO ₃ H ₂ ) RuIII (NH ₃ ) ₄ ( NC) RuII (CN) ₅ ] and Ru (bpy) 2-dioxolene complex.

According to another embodiment of the present invention, the gray scale may be expressed by adjusting the transmittance of the light source passing through the color change layer.

According to another embodiment of the present invention, the control of the transmittance of the light source passing through the color changing layer may be performed by adjusting the intensity of the electric field applied to the color changing layer.

According to another embodiment of the present invention, the control of the transmittance of the light source passing through the color changing layer may be performed by adjusting the time the electric field is applied to the color changing layer.

According to another embodiment of the present invention, the display element further comprises a brightness enhancement layer formed between the color change layer and the phosphor layer, the brightness enhancement layer transmits the light of the light source transmitted through the color change layer, in the phosphor layer The emitted light can reflect.

According to another embodiment of the present invention, the luminance enhancement layer may be formed by alternately stacking material layers having different refractive indices.

According to another embodiment of the present invention, the display device further comprises a first electrode and a second electrode for applying an electric field to the color change layer, the first electrode and the second electrode in the thickness direction of the color change layer Can be formed.

According to another embodiment of the invention, the first electrode and the second electrode for applying an electric field to the color change layer further comprises, the first electrode and the second electrode to form an electric field in the plane direction of the color change layer Can be.

According to another embodiment of the present invention, the first electrode or the second electrode may have a protrusion formed on the surface in the direction in which the electric field is formed.

Although the display device according to the present invention uses a backlight light source, it is not a method of filtering a specific wavelength band in the backlight light source, but is a transmission-emitting display device that excites phosphors using all of the backlight light sources. In addition, since it is possible to change the transmittance of the color change layer by adjusting the intensity of the electric field applied to the color change layer or the time applied, it is easy to drive, and finally the light emitted from the phosphor is recognized by a person. It can have the effect of excellent image quality with. Furthermore, since the structure of the color change layer is simple, it is possible to provide a display device having a simple manufacturing process and low manufacturing cost.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The display device of the present invention includes a light source, a color change layer that receives light from the light source to adjust the transmittance and a phosphor layer that receives light transmitted through the color change layer to emit light of different wavelengths, wherein the color change layer is The color is changed in accordance with the change of the applied electric field, and the display element is driven by adjusting the transmittance of the light source.

1 shows a part of a cross section of a display element of the present invention. Referring to FIG. 1, the display element includes a light source 101, an optical film 102, a substrate 103, a first electrode 104, a color change layer 105, a second electrode 106, and a phosphor layer 107. ) And black matrix 108. The light generated from the light source 101 is transmitted to the phosphor layer 107 through the color change layer 105 whose transmittance is adjusted according to the application of the electric field, and the phosphor layer 107 excited by the supplied light is Emits light in the visible region.

As a light source, a blue light source may be used, and a lamp or a blue LED using plasma discharge may be used. The preferred wavelength band of the light source is 300 to 500 nm, because the light source of such a blue or bluish violet band has high efficiency of exciting the phosphor. The light source passes through the optical film before being supplied toward the substrate. The optical film may include a diffusion plate for scattering the light into a surface light source as a means for uniformly supplying the light supplied from the light source toward the substrate. In FIG. 1, only a direct light source in which a light source is directly positioned on a rear surface of the substrate is illustrated. However, the light source may be positioned at the side of the substrate and a light guide plate may be used to guide light toward the substrate.

The substrate may be a glass substrate or various kinds of polymer resin substrates, and when the polymer resin substrate is used, a flexible display may be realized. A first electrode and a second electrode are formed on the substrate, and a color change layer is formed between the first electrode and the second electrode. The first electrode and the second electrode are patterned for each cell of R, G, and B, and may be made of a transparent conductive material such as indium tin oxide or fluorine tin oxide. The first electrode or the second electrode may be laminated with a patterned metallic electrode layer to improve electrical conductivity.

R, G, and B phosphors are patterned on the second electrode, and a black matrix is formed therebetween. R, G, and B phosphors are preferably made of a material that absorbs blue light and emits light in the visible region. In particular, the phosphor layer is preferably matched with the wavelength of the light source and high in light conversion efficiency in the wavelength range of 300 to 500 nm. When the excitation light is blue light, R phosphors include (Sr, Ca) S: Eu, (Ca, Sr) ₂ Si ₅ N ₈ : Eu, CaSiN ₂ : Eu, (Sr, Ca) AlSiN ₃ : Eu and At least one selected from the group consisting of CaAlSiN ₃ : Eu may be used, and as the G phosphor, SIALON: Eu, SrGa ₂ S ₄ : Eu, Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce, CaSc ₂ O ₄ : Ce, γ -AlON: Mn, γ-AlON: Mn, Mg, Ca-α-sialon: Yb, Ba ₃ Si ₆ O ₁₂ N ₂ : Eu, (SrBa) SiO ₄ : Eu and SrSi ₂ O ₂ N ₂ : Eu At least one selected from the group can be used. In the case where the excitation light is ultraviolet light, R phosphors include Y ₂ O ₂ S: Eu, La ₂ O ₂ S: Eu, (Sr, Ba, Ca, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, Mn _{, LiW 2 O 8: Eu,} Sm and _{Ba 3 MgSi 2 O 8: Eu} , from the group consisting of Mn with at least, and one can be used, G phosphor selected is _{(SrBa) SiO 4: Eu,} ZnS: Cu, Al, At least one selected from the group consisting of Au, ZnS: Cu, Al, BaMgAl ₁₀ O ₁₇ : Eu and SrAl ₂ O ₄ : Eu may be used, and as the B phosphor, (Sr, Ba, Ca, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, BaMg ₂ Al ₁₆ O ₂₇ ; Eu, (Ba, Sr) MgAl ₁₀ O ₁₇ : Eu, ZnS: Ag, Al, ZnS: Ag.Cl, Ca ₃ MgSi ₂ O ₈ : Eu, ( Sr, Ba) ₃ MgSi ₂ O ₈ : Eu and La1-xCexLaAl (Si ₆ -zAlz) O ₁₀ -zNz (z = 1) At least one selected from the group consisting of may be used. If the light supplied through the color change layer is sufficient to realize blue, the B phosphor may not be formed. The black matrix is to prevent color mixing of light emitted from the R, G, and B phosphors and may be formed between the R, G, and B phosphors. Although the forming layer of the black matrix is shown on the color change layer in the figure, it may be formed in any layer as long as it is possible to prevent the color mixture between R, G, and B.

In the display device of the present invention, the transmittance of light supplied from the light source is controlled in the color change layer to express on-off or gray scale. That is, by controlling the transmittance of the light source in the color change layer, the amount of excitation light supplied to the phosphor layer can be adjusted to control whether the phosphor emits light and the light intensity. Since the color change layer changes color according to the intensity of the applied electric field, the color change layer operates on a principle of controlling the amount of absorption of light supplied from the light source.

Figure 2 illustrates the cross-sectional structure and color change principle of the color change layer applied to the present invention. Referring to FIG. 2A, a first electrode 202 is formed on a substrate 201, and a color change layer 203 and a second electrode 204 are sequentially stacked thereon. A DC signal (or an AC signal may be connected, although not shown) is connected between the first electrode 202 and the second electrode 204. When no signal is applied, no electric field is formed in the color change layer 203 and light supplied from the light source is transferred to the substrate 201, the first electrode 202, the color change layer 203, and the second electrode 204. Penetrates. Referring to FIG. 2B, when an electric field is formed between the first electrode 202 and the second electrode 204, the color change layer 203 causes a color change, and the discolored color change layer 203a It will absorb some or all of the light supplied from the light source. By this principle, the intensity of the excitation light supplied to the phosphor can be changed.

(흡수피크 중심: 450㎚),

(흡수피크 중심: 391㎚, 410㎚, 418㎚),

(흡수피크 중심: 475㎚),

(흡수피크 중심: 396㎚, 435㎚, 461㎚) 등을 들 수 있다. 또한 색변화층 물질 중 무기착물로는

(흡수피크 중심: 475㎚, 450㎚, 475㎚), K[(NC₅H₄CH₂PO₃H₂)RuIII(NH₃)₄(NC)RuII(CN)₅](흡수피크 중심: 440㎚), K[(NC₅H₄PO₃H₂)RuIII(NH₃)₄(NC)RuII(CN)₅](흡수피크 중심: 450㎚), Ru(bpy)2-dioxolene 착물(흡수피크 중심: 450㎚, 440㎚) 등을 들 수 있다.The color change layer may include a color change material, a solvent, and an electrolyte. The color change material is a material whose color changes with the application of an electric field. The color change material reversibly changes with the supply and removal of the electric field. The change in color of the color change material means absorption of light in a specific wavelength range. In the present invention, a color change material capable of absorbing the wavelength of the blue series may be used due to the application of an electric field. The material that can be used as the color change layer in the present invention is various. The material forming the color change layer is a material that absorbs light in the wavelength range of 300 to 500 nm. Among the color change layer materials which can be used in the present invention, organic or organic polymers include biphenyl dicarboxylic acid diethyl ester (absorption peak center: 460 nm), dioctyl-substituted 2,3-di (thien-3-yl) -5,7 -di (thien-2-yl) thieno [3,4- b ] pyrazine (absorption peak center: 360 nm), poly (3,4-propylenedioxythiophene) diester (absorption peak center: 480 nm), poly (3,4 -propylenedioxythiophene) diol (absorption peak center: 480 nm), thiophene / EDOT / phenylene complex (absorption peak center: 450 nm), poly-bithiophene (absorption peak center: 450 nm), N, N-bis (4-aminophenyl) -N ', N'-di (4-methoxylphenyl) -1,4-phenylenediamine (absorption peak center: 430 nm), poly [N-9-heptadecanyl-2,7-carbazole-alt-5,7-di ( 3-octylthien-2-yl) -2,3-di (thien-3-yl) -thieno [3,4-b] pyrazine (absorption peak center: 430 nm), poly [N-9-heptadecanyl-2, 7-carbazole-alt-5,7-di (3-octylthien-2-yl) -2,3-di (phen-1-yl) -thieno [3,4-b] pyrazine (absorption peak center: 420 nm ), poly [N-9-heptadecanyl-2,7-carbazole-alt-5,7-di (3-octylthien-2-yl) -2,3-di (4-octylphen-1-yl) -th ieno [3,4-b] pyrazine (absorption peak center: 460 nm), poly (5,8-bis (2,3-dihydrothieno [3,4-b] [1,4] dioxin-5-yl) quinoxaline ) (Absorption peak center: 410 nm), poly (5,8-bis (2,3-dihydrothieno [3,4-b] [1,4] dioxin-5-yl) -2,3-di (thiophen- 2-yl) quinoxaline) (absorption peak center: 405 nm), poly (1,4-bis (2- [3 ', 4'-ethylenedioxy] thienyl) -2-methoxy-5-2''-ethylhexyloxybenzene) ( Absorption peak center: 470 nm), poly (3-methyl-2-{[3- (4-vinyl-benzyl) -3H-benzothiazol-2-ylidene] -hydrazono} -2,3-dihydro-benzothiazole-6- poly (3,4-ethylenedioxythiophene) doped with sulfonic) acid (absorption peak center: 393 nm),

(Absorption peak center: 450 nm),

(Absorption peak center: 391 nm, 410 nm, 418 nm),

(Absorption peak center: 475 nm),

(Absorption peak center: 396 nm, 435 nm, 461 nm) etc. are mentioned. In addition, as inorganic complexes among the color change layer materials,

(Absorption peak center: 475 nm, 450 nm, 475 nm), K [(NC ₅ H ₄ CH ₂ PO ₃ H ₂ ) RuIII (NH ₃ ) ₄ (NC) RuII (CN) ₅ ] (absorption peak center: 440 Nm), K [(NC ₅ H ₄ PO ₃ H ₂ ) RuIII (NH ₃ ) ₄ (NC) RuII (CN) ₅ ] (absorption peak center: 450 nm), Ru (bpy) 2-dioxolene complex (absorption peak Center: 450 nm, 440 nm), and the like.

Therefore, the color change layer used in the present invention may include at least one color change material selected from the group consisting of the organic materials, organic polymers and inorganic complexes listed above, NMP (N-methyl pyrrolidine) is used as a solvent The electrolyte may be tetra-n-butylammonium perchlorate (TBAP) or tetra-n-butylammonium iodide (TBAI). In addition, the color change layer may further include ferrocene (ferrocene, Fc). Ferrocene acts as an electron donor as a counter redox material, and the inclusion of ferrocene in the color change layer can increase the cycle stability of the color change material and lower the operating voltage.

Figure 3 shows the absorption spectrum when an electric field is applied to the color change layer consisting of DEB, NMP, TBAP and Fc. Referring to Figure 3, the color change layer is formed to absorb energy at 400 to 500nm. Therefore, the transmittance of light supplied from the light source of the display element can be adjusted efficiently.

The color change layer absorbs light in a specific wavelength range as the electric field intensity changes. Therefore, in the present invention, each cell of the display device can be turned on or off using gray scale.

Figure 4 shows a method of controlling the on-off of each of the R, G, B cells by adjusting the intensity of the electric field. Referring to FIG. 4, an electric field is not applied to the first electrode 204a formed in the R region among the first electrodes 104a, 104b, and 104c formed on the substrate 103, and the first electrode in the G and B regions ( In 104b and 104c, only the phosphor layer 107a of the R cell is emitting light while an electric field is applied. The first electrodes 104b and 104c in the G and B regions form an electric field in a direction opposite to the second electrodes 106b and 106c. The R region to which the electric field is not applied is the color change layer 105. ) Does not change color, and the color change layers of the G and B regions to which the electric field is applied become the color change layer 105a discolored while the color change occurs. When the color change occurs, the transmittance of light of the light source 101 supplied through the optical film 102 is lowered, so that the R cells are in the on state and the G and B cells are in the off state. In this way, when the light transmission is blocked close to zero in the color change layer, the phosphor layer does not emit light. However, if the transmittance is appropriately adjusted, the gray level of the display device can be expressed.

The method of controlling the light transmittance in the color change layer may be various. The first method is to adjust the intensity of the electric field formed between the first electrode and the second electrode. The intensity of the electric field may be adjusted by changing the intensity of the voltage applied to the first electrode or the second electrode. As the intensity of the electric field increases, the color of the color change layer becomes darker, and the amount of absorbing light in a specific wavelength band increases, thereby reducing the amount of excitation light supplied to the phosphor layer, thereby reducing the amount of light emitted from the corresponding cell. The second method is to fix the intensity of the voltage applied to the first electrode or the second electrode and to adjust the time for which the voltage is applied. This method may have an advantage in driving the display element in that the voltage applied to the electrode can be fixed. In order to control the time for which the voltage is applied, the voltage may be supplied in the form of a pulse, and the time for which the voltage is applied to the color change layer may be adjusted by adjusting the pulse width. In order to control the time for which the voltage is applied, a method of adjusting the number of pulses having a predetermined pulse width may also be applied. In this case, the time for which the voltage is applied is adjusted according to the number of pulses.

Electrodes applied to the display device of the present invention can be manufactured in various structures and shapes. The electrode formation structure may be formed on the upper and lower portions of the color change layer such that the first electrode and the second electrode form an electric field in the thickness direction of the color change layer. This structure is the same as that shown in Figure 1, because the distance between the first electrode and the second electrode is determined according to the thickness of the color change layer has the advantage of uniformly adjusting the intensity of the electric field formed between the electrodes of each cell Have Another electrode formation structure is such that the first electrode and the second electrode form an electric field in the direction of the plane of the color change layer. In such a structure, the first electrode and the second electrode may be formed on the same layer, thereby providing a manufacturing process. Can be simplified.

The first electrode or the second electrode applied to the display device of the present invention may have a protrusion formed on a surface of the electric field is formed. Protrusions formed on one surface of the electrode can concentrate the electric field to locally strengthen the intensity of the electric field formed in the color change layer, and consequently shorten the reaction time of the color change layer due to the application of voltage. When the response time of the color change layer is shortened, it is advantageous to realize a moving image with rapid movement, and when applying a voltage in the form of pulse to the electrode, the number of pulses applied at a certain time can be increased, so that various gray levels can be expressed. Done. The protrusions may be formed on only one or both of the first electrode and the second electrode, and the protrusions may be formed in various shapes such as horns or rods having narrow upper portions.

The display device of the present invention can increase the brightness by applying the brightness enhancement layer. 5 is a cross-sectional view of the display device to which the luminance enhancement layer is applied. Referring to FIG. 5, the display device includes a light source 101, an optical film 102, a substrate 103, a first electrode 104, a color change layer 105, a second electrode 106, and a phosphor layer 107. ) And the black matrix 108 are the same as those in FIG. 1, but a luminance enhancement layer 109 is further formed between the second electrode 106 and the phosphor layer 107.

Fig. 6 shows the cross-sectional structure and the principle of luminance enhancement of the luminance enhancement layer used in the display element of the present invention. Referring to FIG. 6, the luminance enhancement layer has a structure in which a material layer H having a high refractive index and a material layer L having a low refractive index are repeatedly stacked. The luminance enhancement layer has a characteristic of passing light of a relatively short wavelength and reflecting light of a long wavelength. The lower and upper end layers of the luminance-enhancing layer consist of a material layer (H) having a high refractive index having a thickness corresponding to 1/8 of the wavelength λ of transmitted light, between which the material layer (L) having a low refractive index and The material layer H having a high refractive index is alternately repeated with a thickness of 1/4 of the wavelength λ of transmitted light, forming an odd number of layers. At this time, the number of intermediate layers except for the upper and lower end layers is preferably an odd number of 3 to 13. If the number of intermediate layers is less than 3, the reflection efficiency of high wavelength light is low, and if it exceeds 13, the transmission efficiency of low wavelength light is too low. The material layer having the high refractive index and the material layer having the low refractive index included in the luminance enhancing layer may be TiO ₂ and SiO ₂ , respectively.

7 illustrates a principle of increasing luminance by the luminance enhancement layer in the display device of the present invention. FIG. 7 shows the luminance enhancement layer and the phosphor layer separately for convenience of description. Referring to FIG. 7, the excitation light transmitted through the color change layer passes through the luminance enhancement layer 109 as it is and is transmitted to the phosphor layer 107, and the phosphor layer 107 emitted by the excitation light is higher than the excitation light. The light of the wavelength emits up and down direction. In this case, the light emitted in the upward direction of the phosphor layer 107 is directly emitted to the front surface of the display element, and the light emitted in the downward direction is reflected to the brightness enhancement layer 109 and emitted to the front surface. Therefore, when the luminance enhancement layer is applied to the display element, the light emitted from the rear surface and thus did not contribute to the luminance enhancement contributes to the luminance, thereby increasing the overall luminance of the display element.

A method of manufacturing a panel of the display element of the present invention will be described. First, a transparent electrode layer made of indium tin oxide or fluorine tin oxide is formed on a glass substrate or a transparent polymer resin substrate using a sputtering method or an electron beam deposition method, and the transparent electrode layer is patterned for each cell using a photolithography technique. Subsequently, a color change layer is formed by coating a solution including a color change material such as DEB, a solvent, an electrolyte, and the like on the patterned transparent electrode layer by dipping or spin coating. Subsequently, a transparent electrode layer is formed on the color change layer by sputtering, electron beam evaporation, or the like. Subsequently, TiO ₂ and SiO ₂ are repeatedly stacked by using an electron beam deposition method to form a luminance enhancement layer on the transparent electrode layer. Subsequently, R, G, and B phosphors are coated on the brightness enhancement layer by screen printing, inkjet, or the like. Finally, a black matrix layer is formed by screen printing or inkjet. When the optical film and the light source are installed on the rear surface of the manufactured panel and the driving circuit is connected to the panel, the manufacturing of the display device can be completed.

Hereinafter, the present invention will be described in more detail with reference to preferred examples. However, these examples are intended to illustrate the present invention in more detail, it will be apparent to those skilled in the art that the scope of the present invention is not limited thereby.

Example 1 (Manufacture of Shutter Using Color Changing Layer)

A glass substrate coated with indium tin oxide (130 nm thick) was used as the upper and lower substrates, and a color change layer was formed between the indium tin oxide electrodes. The spacing between the electrodes was controlled by using a 60 µm thick surlyn tape, and the color-changing layer was 0.1M of dye biphenyl dicarboxylic acid diethyl ester (DEB) in N-methyl pyrrolidone (NMP) solvent and tetra -n-butylammonium perchlorate (TBAP) was prepared by mixing 0.05 M and electron donor material ferrocene (Fc) at a concentration of 0.03 M. The shutter using the color change layer was operated by applying a DC signal to the upper and lower electrodes. 8 is a schematic cross-sectional view of a shutter using a color change layer manufactured according to Example 1 of the present invention.

Example 2 (Manufacture of Display Device Using Color Changing Layer)

On the upper substrate of the shutter using the color change layer prepared according to Example 1, a structure not coated with phosphor, a structure coated with SrGa ₂ S ₄ : Eu, and a structure coated with (Sr, Ca) AlSiN ₃ : Eu were formed. To produce display elements of B, G, and R cells, respectively.

Experimental Example 1

A voltage was applied to the upper and lower electrodes of the shutter using the color change layer manufactured according to Example 1, and the color change was visually observed. Referring to FIG. 9, the shutter showed a transparent color when no voltage was applied and became yellow when a 4V signal was applied. Therefore, it can be seen that when the voltage is applied to the shutter, light in the B region is absorbed.

Experimental Example 2

The blue LED was installed at the lower part of the shutter using the color change layer manufactured according to Example 1, and the transmittance of light generated from the blue LED was measured while applying voltages of 0V and 4V to the upper and lower electrodes. Referring to FIG. 10, when no voltage is applied, light transmittance reaches 100%, but when 4 V is applied, light transmission is effectively blocked at a wavelength range of 400 to 500 nm. In addition, it was found that the wavelength band where the light is blocked coincides very well with the wavelength band of the light generated by the blue LED. From these results, the performance of the shutter using the color change layer prepared according to Example 1 could be confirmed.

Experimental Example 3

A blue LED was installed at the bottom of the shutter using the color change layer manufactured according to Example 1, and the transmittance of light generated from the blue LED was measured while changing the magnitude of the voltage applied to the upper and lower electrodes. Referring to FIG. 11, it can be seen that the transmittance of light generated by the blue LED is changed while the applied voltage is changed from 1V to 4.5V. Therefore, when such a shutter is applied to the display device, it can be seen that various gray levels can be expressed by a change in the magnitude of the voltage.

Experimental Example 4

Contrast ratios were measured by driving cells B, G, and R of the display device manufactured according to Example 2 at voltages of 0V and 4V. Referring to FIG. 12A, the B cell has a structure in which the phosphor is not formed separately, and the contrast ratio is measured to be 11: 1 when 0V is applied and when 4V is applied. Referring to FIG. 12B, in the case of the G cell, the SrGa ₂ S ₄ : Eu phosphor was coated, and the contrast ratio was measured to be 11: 1 when 0V and 4V were applied. In addition, referring to FIG. 12C, the R cell has a (Sr, Ca) AlSiN ₃ : Eu phosphor coated structure, and the contrast ratio was measured to be 8: 1 when 0V and 4V were applied. From these results, it can be seen that the driving of each cell of B, G, and R occurs effectively.

Experimental Example 5

Each cell B, G, and R of the display device manufactured according to Example 2 was driven at a voltage of 0 V, and color coordinates were measured and displayed on a CIE color coordinate system. Referring to FIG. 13, the color coordinate of cell B is represented by x = 0.149 and y = 0.062, the color coordinate of cell G is represented by x = 0.291, y = 0.632, and the color coordinate of R cell is x = 0.639 and y = 0.359. Was indicated. From these results, it can be seen that the display device of the present invention can effectively implement natural colors.

1 shows a part of a cross section of a display element of the present invention.

Figure 2 illustrates the cross-sectional structure and color change principle of the color change layer applied to the present invention.

Figure 3 shows the absorption spectrum when an electric field is applied to the color change layer consisting of DEB, NMP, TBAP and Fc.

Figure 4 shows a method of controlling the on-off of each of the R, G, B cells by adjusting the intensity of the electric field.

5 is a cross-sectional view of the display device to which the luminance enhancement layer is applied.

6 illustrates a cross-sectional structure and a principle of luminance enhancement of the luminance enhancement layer used in the display device of the present invention.

7 illustrates a principle of increasing luminance by the luminance enhancement layer in the display device of the present invention.

8 is a schematic cross-sectional view of a shutter using a color change layer manufactured according to Example 1 of the present invention.

Figure 9 shows the color change of the color change layer prepared according to Example 1 of the present invention.

Figure 10 shows the transmission control effect of the excitation light by the color change layer prepared according to Example 1 of the present invention.

Figure 11 shows the control of the transmittance of the excitation light by the color change layer prepared according to Example 1 of the present invention.

12 illustrates the operation of the display device manufactured according to Example 2 of the present invention and the corresponding contrast ratio for each cell.

FIG. 13 shows the color coordinates of each cell of the display device manufactured according to Example 2 of the present invention in a CIE color coordinate system.

Claims (12)

Light source; A color change layer for controlling a transmittance of the light source by changing a color by a change in an applied electric field; And Phosphor layer for receiving light transmitted through the color change layer to emit light of a different wavelength; including, further comprising a brightness enhancement layer formed between the color change layer and the phosphor layer, the brightness enhancement layer is a color change And a light emitted from the phosphor layer and reflecting light emitted from the phosphor layer. The method of claim 1, The center wavelength of the light source is positioned in the range of 300 to 500 nm, and the color change layer has a light absorption band in the range of 300 to 500 nm when an electric field is applied. The method of claim 1, The color change layer is biphenyl dicarboxylic acid diethyl ester, dioctyl-substituted 2,3-di (thien-3-yl) -5,7-di (thien-2-yl) thieno [3, 4- b ] pyrazine, poly (3,4-propylenedioxythiophene) diester, poly (3,4-propylenedioxythiophene diol, thiophene / EDOT / phenylene complex, poly-bithiophene , N, N-bis (4-aminophenyl) -N ', N'-di (4-methoxyphenyl) -1,4-phenylenediamine, poly [N-9-heptadecanyl-2,7- Carbazole-alt-5,7-di (3-octylthien-2-yl-2,3-di (thien-3-yl) -thieno [3,4-b] pyrazine, poly [N-9- Heptadecanyl-2,7-carbazole-alt-5,7-di (3-octylthien-2-yl) -2,3-di (fe-1-yl) -thieno [3,4-b ] Pyrazine, poly [N-9-heptadecanyl-2,7-carbazole-alt-5,7-di (3-octylthien-2-yl) 2,3-di (4-octylphen-1- Yl) -thieno [3,4-b] pyrazine, poly (5,8-bis (2,3-dihydrothieno [3,4-b] [1,4] dioxin-5-yl) quinox Saline, poly (5,8-bis (2,3-dihydrothieno [3,4-b] [1,4] dioxin-5-yl) -2,3-di (thiophen-2- ) Quinoxaline, poly (1,4-bis (2- [3'4'-ethylenedioxy] thienyl) -2-methoxy-5-2 ''-ethylenehexyloxybenzene, poly (3-methyl- Doped with 2-{[3- (4-vinyl-benzyl) -3H-benzothiazole-2-ylidene] -hydrazono} -2,3-dihydro-benzothiazole-6-sulphonic) acid Poly (3,4-ethylenedioxythiophene),

,

,

And

Display device, characterized in that at least one selected from the group consisting of. The method of claim 1, The color change layer is

, K [(NC ₅ H ₄ CH ₂ PO ₃ H ₂ ) RuIII (NH ₃ ) ₄ (NC) RuII (CN) ₅ ], K [(NC ₅ H ₄ PO ₃ H ₂ ) RuIII (NH ₃ ) ₄ ( NC) RuII (CN) ₅ ] and Ru (bpy) 2-dioxolene complex. The method of claim 1, Display element characterized in that to represent the gray scale by adjusting the transmittance of the light source passing through the color change layer. The method of claim 5, The display device, characterized in that for controlling the transmittance of the light source passing through the color change layer, by adjusting the intensity of the electric field applied to the color change layer. The method of claim 5, The display device, characterized in that for controlling the transmittance of the light source passing through the color change layer, by adjusting the time the electric field is applied to the color change layer. delete The method of claim 1, The luminance-enhancing layer is a display device, characterized in that formed by alternately stacking material layers of different refractive index. The method of claim 1, And a first electrode and a second electrode for applying an electric field to the color change layer, wherein the first electrode and the second electrode form an electric field in a thickness direction of the color change layer. The method of claim 1, And a first electrode and a second electrode for applying an electric field to the color change layer, wherein the first electrode and the second electrode form an electric field in a plane direction of the color change layer. The method according to any one of claims 10 and 11, The first electrode or the second electrode is a display element, characterized in that the protrusion is formed on the surface in the direction in which the electric field is formed.

Images