JP2006318825A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve contrast in a bright place of a display device having phosphor layers and to prevent degradation of luminance. <P>SOLUTION: The phosphor layers 7 emitting visible light of respective colors such as red, green and blue for forming an image of this display device are respectively formed by mixing phosphor particles p1 formed of phosphor material emitting visible light of the respective colors such as red, green and blue by being excited by vacuum ultraviolet rays with granular pigment p2 absorbing light; and each surface of the granular pigment p2 is coated with a phosphor thin film (f) formed of a phosphor material emitting light of the same color as the emission color of the phosphor particles. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a configuration of a display device including a phosphor layer that emits light when excited by an excitation source.

  In general, a display device including a phosphor layer that emits light when excited by an excitation source is, for example, a plasma display panel (PDP) that is one of gas discharge display devices.

  In this PDP, a row electrode pair, a dielectric layer that covers the row electrode pair, and a protective layer that covers the dielectric layer are provided on the inner surface of one of the pair of substrates facing each other through the discharge space. On the inner surface of the other substrate, a column electrode forming a discharge cell in a matrix at a portion orthogonal to the row electrode pair and intersecting the row electrode pair in the discharge space, a column electrode protective layer covering the column electrode, and the column electrode A structure is provided in which a phosphor layer colored in red, green, and blue is provided for each discharge cell on the protective layer.

A discharge gas containing xenon gas is sealed in the discharge space.
In the PDP having such a structure, an address discharge is selectively generated between one row electrode and a column electrode of the row electrode pair, and wall charges are generated in the dielectric layer at a portion facing the discharge cell by the address discharge. In the formed discharge cell (light emitting cell), a sustain discharge is generated between the row electrodes of the row electrode pair, and vacuum ultraviolet rays generated from the xenon gas in the discharge gas excite the phosphor layer by this sustain discharge. By generating visible light of each color of red, green, and blue, an image corresponding to the video signal is formed on the panel surface.

A phosphor that emits visible light when excited by vacuum ultraviolet rays as provided in this PDP conventionally emits green as (Y, Gd) BO ₃ : Eu (GYBO) as a phosphor emitting red light. Zn ₂ SiO ₄ : Mn (ZSM) is known as a phosphor, and BaMgAl ₁₀ O ₁₇ : Eu (BAM) is known as a phosphor emitting blue light.

  The phosphor layers formed by applying these red, green, and blue phosphors onto the substrate all appear white in natural light, so they reflect external light incident from the panel surface. There is a problem of deteriorating the bright contrast of the image.

  Conventionally, in order to improve the problems in this phosphor layer, red, green, and blue phosphors are mixed with a light absorbing material that absorbs light in a wavelength region other than the wavelength of the emission color of each phosphor. There has been proposed a display device having a phosphor layer (see Patent Document 1).

  However, in this conventional display device, as the amount of the light absorbing material mixed into the phosphor layer increases, the amount of incident light absorbed from the panel surface by the phosphor layer increases, and the bright place contrast of the formed image. However, the higher the content of the light absorbing material in the phosphor layer, the more the vacuum ultraviolet ray is blocked by the light absorbing material. Therefore, the amount of vacuum ultraviolet light incident on the phosphor particles in the phosphor layer is reduced. There is a problem that the luminance is reduced due to the decrease.

Japanese Patent Laid-Open No. 11-131059

  One of the technical problems of the present invention is to solve the problems in the display device including the phosphor layer formed of the phosphor material excited by the conventional excitation source as described above.

  In order to achieve the above object, a phosphor according to a first invention (invention according to claim 1) is a display device including a phosphor layer that generates visible light when excited by an excitation source. The phosphor layer is formed by mixing phosphor particles formed of a fluorescent material that emits visible light of a predetermined color when excited by an excitation source, and non-luminescent particles formed of a non-luminescent material, The surface of the non-light emitting particles is covered with a phosphor thin film formed of a phosphor material.

  The present invention provides a fluorescent material that emits visible light of each color of red, green, and blue when the phosphor layers that emit visible light of each color of red, green, and blue are excited by vacuum ultraviolet rays. A phosphor thin film formed by mixing phosphor particles formed by the above and a particulate pigment that absorbs light, and the surface of the particulate pigment is formed of a phosphor material that emits light of the same color as the phosphor particles The display device coated with is the best embodiment.

  The display device according to the above embodiment is a light absorbing material in which phosphor layers of red, green, and blue colors are coated with phosphor particles and a phosphor thin film that emits light of the same color as the phosphor particles. A mixture of pigments prevents external light incident from the panel surface of the display device from being absorbed by the pigment in the phosphor layer, resulting in deterioration of bright place contrast due to reflection of external light. At the same time, the surface of the pigment is coated with a phosphor thin film that is excited by vacuum ultraviolet rays and emits light of the same color as that of the phosphor particles. There is no possibility that the brightness of the formed image is lowered due to the mixing of the pigment as the light absorbing material in the phosphor layer.

  FIG. 1 shows an example of an embodiment of a display device according to the present invention. A PDP which is a kind of gas discharge display device having a phosphor layer formed of a phosphor material excited by vacuum ultraviolet rays is shown. 2 shows a configuration around one discharge cell when a cross section is taken along the column direction.

  In FIG. 1, a PDP has row electrodes extending in the row direction (perpendicular to the paper surface in FIG. 1) and arranged in parallel in the column direction (left-right direction in FIG. 1) on the back surface of the front glass substrate 1 as a display surface. A pair (X, Y) is formed.

  The row electrodes X and Y constituting the row electrode pair (X, Y) are respectively arranged at equal intervals along the bus electrodes Xa and Ya extending in a strip shape in the row direction and the bus electrodes Xa and Ya. It consists of transparent electrodes Xb, Yb that extend from the bus electrodes Xa, Ya to the other row electrode pair and are opposed to each other via a discharge gap g.

  A dielectric layer 2 is formed on the back side of the front glass substrate 1, and the row electrode pair (X, Y) is covered with the dielectric layer 2.

  On the other hand, on the display side surface of the rear glass substrate 4 facing the front glass substrate 1 through the discharge space, the address electrode D is a transparent electrode Xb in which each pair of row electrodes (X, Y) is paired with each other. And extend in the column direction orthogonal to the row electrode pair (X, Y) at a position opposite to Yb, and are arranged in parallel at predetermined intervals in the row direction.

  A white column electrode protective layer (dielectric layer) 5 covering the address electrodes D is further formed on the display side surface of the rear glass substrate 4.

  Then, on this column electrode protective layer 5, horizontal wall portions 6 </ b> A that extend in the row direction and are juxtaposed in the column direction at positions facing the bus electrodes Xa and Ya, respectively, and each address electrode D juxtaposed in the column direction A partition wall 6 that is formed in a substantially lattice shape is formed by a vertical wall portion (not shown) that extends in the column direction and is arranged in parallel in the row direction at a position opposite to the intermediate position. The space is partitioned in a matrix for each portion facing the transparent electrodes Xb, Yb opposed via the discharge gap g of each row electrode pair (X, Y), and discharge cells C are formed respectively.

  Further, in each discharge cell C, the surface of the column electrode protection layer 6 between the horizontal wall portion 6A and the vertical wall portion of the partition wall 6 and the five surfaces of the horizontal wall portion 6A and the side surface of the vertical wall portion are respectively red, The phosphor layers 7 color-coded green and blue are formed so as to be arranged in the row direction in the order of red, green and blue.

  The configuration of the red, green, and blue phosphor layers 7 will be described in detail later.

  A discharge gas containing xenon gas is enclosed in the discharge space between the front glass substrate 1 and the back glass substrate 4.

  As will be described later, the PDP red, green, and blue phosphor layer 7 has a discharge generated between the transparent electrodes Xb and Yb facing each other through the discharge gap g of the row electrode pair (X, Y) ( Sustain discharge) is excited by vacuum ultraviolet rays generated from xenon gas in the discharge gas, and emits visible light of red, green and blue colors, respectively.

FIG. 2 is a partially enlarged view of the configuration of the phosphor layer 7.
In FIG. 2, phosphor layers 7 of red, green and blue colors emit phosphors of the same color as the emission color of the phosphor particles p1, respectively, on the phosphor particles p1 of red, green and blue, respectively. A pigment p2 having the same color as the emission color of the phosphor particles p1 whose surface is coated with the thin film f is mixed and formed.

  Each of the red, green, and blue pigments p2 is a light absorbing material that absorbs light in a wavelength region other than the color (red, green, blue) of the pigment in visible light.

  The composition and particle size of each color of the phosphor particles p1 are as follows.

Red phosphor particles - _{Composition: (Y, Gd) BO 3} : Eu (GYBO)
Particle size: about 1 to 3 μm
Green phosphor particles-composition: Zn ₂ SiO ₄ : Mn (ZSM)
Particle size: about 1 to 3 μm
Blue phosphor particles-composition: BaMgAl ₁₀ O ₁₇ : Eu (BAM)
Particle size: about 1 to 3 μm
The composition and particle size of each color of the pigment p2 are as follows.

Red pigment-composition: Fe ₂ O ₃
Particle size: about 0.1 to 0.02 μm
Green pigments - Composition _{1: (Co, Ni, Zn} ) 2 TiO 4
Particle size: about 0.3 μm
Composition 2: (Co, Mg) (Al, Cr) ₂ O ₄
Particle size: about 0.03 μm
Blue pigment-composition 1: CoAl ₂ O ₄
Particle size: about 0.1 μm
Composition 2: CoAl ₂ O ₄
Particle size: about 0.01 μm
The composition, film thickness, and raw material of each color of the phosphor thin film f are as follows.

Green phosphor thin - _Composition: Y ₂ O _3: Tb
Film thickness: 260nm
Raw material: Y (DPM) ₃ , Tb (DPM) ₃
Blue phosphor thin - _Composition: Y ₂ O _3: Tm
Film thickness: 210nm
Raw materials: Y (DPM) ₃ , Tm (DPM) ₃
Red phosphor thin - _Composition: Y ₂ O _3: Eu
Film thickness: 300nm
Raw material: Y (DPM) ₃ , Eu (DPM) ₃

  In the PDP having the phosphor layer 7 having the above-described configuration, as shown in FIG. 2, when external light L enters from the front glass substrate 1 side constituting the panel surface, red, green, blue In the phosphor layer 7 of each color, light outside the wavelength range of each color passes through the phosphor thin film f and is absorbed by the pigment p2, and only light Lr in the same wavelength range as the color of the phosphor layer 7 is reflected. Is done.

  For example, in the green phosphor layer 7, the light in the wavelength range other than green of the incident external light L is absorbed by the green pigment p <b> 2, and only the light Lr in the green wavelength range is reflected.

  As described above, the sustain discharge is generated between the transparent electrodes Xb and Yb facing each other through the discharge gap g of the row electrode pair (X, Y), and the discharge gas sealed in the discharge space is generated. When the vacuum ultraviolet ray UV is generated from the xenon gas, the phosphor ultraviolet ray p1 and the phosphor thin film f of each phosphor layer 7 are excited by the vacuum ultraviolet ray UV, and each of the red, green and blue colors is excited. Light emission Ra is performed.

  As described above, in the PDP, the phosphor layer 7 of each color of red, green, and blue emits the phosphor particles p1 that emit light of each color, and emits light of the same color as the emission color of each of the phosphor particles p1. Since the pigment p2 having the same color as the emission color of the phosphor particles p1 whose surface is coated with the phosphor thin film f to be formed is mixed, the external light L incident from the panel surface is absorbed. The deterioration of the bright place contrast due to the reflection of outside light is prevented, and the surface of the pigment p2 which is a light absorbing material mixed in the phosphor layer 7 is excited by vacuum ultraviolet rays to emit light of the phosphor layer 7 Since the light is also emitted on the surface of the pigment p2 by being coated with the phosphor thin film f that emits light of the same color as the above, even if the pigment p2 that is a light absorbing material is mixed in the phosphor layer 7, Not be reduced brightness as come.

  In the above, the phosphor thin film f is formed so that the optical film thickness (thin film thickness × thin film refractive index) is an integral multiple of the half wavelength of the emission wavelength of each color phosphor particle p1. Thus, by using optical interference, the color of the reflected light from the pigment p2 can be made the same as the emission color of the phosphor layer 7.

  3 to 7 are graphs showing the composition of the pigment p2 mixed in the phosphor layer 7 of the PDP, the luminance for each particle diameter, and the reflectance (Ref.) Of external light.

  In addition, the comparative example shown by each figure has shown the brightness | luminance when the coating by the fluorescent substance thin film is not given to the same pigment.

That is, FIG. 3 shows a case where a red pigment Fe ₂ O ₃ having a particle size of about 0.1 to 0.02 μm is mixed in the red phosphor layer 7, compared with the comparative example, It can be seen that the brightness is greatly increased by coating the pigment with the phosphor thin film.

FIG. 4 shows a case where a green pigment (Co, Ni, Zn) ₂ TiO ₄ having a particle size of about 0.3 μm is mixed in the green phosphor layer 7, compared with the comparative example, It can be seen that the brightness is greatly increased by coating the pigment with the phosphor thin film.

FIG. 5 shows a case where a green pigment (Co, Mg) (Al, Cr) ₂ O ₄ having a particle size of about 0.03 μm is mixed in the green phosphor layer 7, and in the case of the comparative example. In comparison, it can be seen that the brightness is greatly increased by coating the pigment with the phosphor thin film.

FIG. 6 shows a case where a blue pigment CoAl ₂ O ₄ having a particle diameter of about 0.1 μm is mixed in the blue phosphor layer 7, and the pigment is formed by the phosphor thin film as compared with the comparative example. It can be seen that the brightness is greatly increased by the coating.

FIG. 7 shows a case where a blue pigment CoAl ₂ O ₄ having a particle diameter of about 0.01 μm is mixed in the blue phosphor layer 7, and the pigment is formed by the phosphor thin film as compared with the comparative example. It can be seen that the brightness is greatly increased by the coating.

  If the phosphor thin film f is formed of the same phosphor material as the phosphor particles p1 in the red, green, and blue phosphor layers 7 of the PDP, the row electrode Y and the column electrode D are used. With respect to the address discharge voltage generated between them, the exposed substances on the surface of each phosphor layer are aligned and the respective secondary electron emission characteristics are approximated, whereby each of the phosphor layers 7 of red, green, and blue colors. The difference can be reduced.

  Further, in the above PDP, when the phosphor thin film is coated on the surface of a white non-emissive material that is not a pigment, instead of the pigment p2, the reflected light is reduced by the optical interference effect, and almost the same contrast is obtained. An improvement effect can be obtained.

  As a film forming method for forming the phosphor thin film f on the pigment p2, various methods such as a vapor deposition method, a sputtering method, and a liquid phase method can be used, but it is preferable to use a chemical vapor deposition method (CVD).

  FIG. 8 shows an example of an apparatus for coating the pigment p2 with the phosphor thin film f by CVD.

  In FIG. 8, the coating apparatus 10 includes a nozzle 13 disposed above a conveyance path 12 that conveys the heating dish 11 in which the granular pigment p <b> 2 is placed, and in the middle of a pipeline 14 connected to the nozzle 13, A vaporizer 15 for vaporizing the CDV material (fluorescent material) m is connected.

  A reaction gas supply pipe 16 is connected to a portion of the pipe line 14 between the nozzle 13 and the vaporizer 15.

  In the coating apparatus 10, the CDV material m is vaporized by the vaporizer 15, and the vaporized vapor of the CDV material m is carried by the carrier gas flowing from the upstream side into the pipe 14 and supplied to the nozzle 13. The

At this time, air or a reaction gas such as O ₂ or O ₃ is supplied into the pipe line 14 from the reaction gas supply pipe 16 connected to the pipe line 14 on the downstream side of the vaporizer 15, so that the CDV material m Mixed with steam.

  When the heating dish 11 containing the granular pigment p2 is conveyed on the conveying path 12 and is positioned below the nozzle 13, the nozzle is directed toward the heated pigment p2 in the heating dish 11. 13, the vapor of the CDV material m mixed with the reaction gas is sprayed, and the phosphor thin film as described above is formed on the surface of the pigment p2 by the fluorescent material which is the CDV material.

FIG. 9 shows another example of the coating apparatus.
In FIG. 9, the coating apparatus 20 is provided with a conduit 21 having an inlet 21 </ b> A for the granular pigment p <b> 2 at the upper end and an outlet 21 </ b> B at the lower end in a substantially vertical direction. (Fluorescent material) A vaporizer 22 that vaporizes m is connected by a pipe line 23.

  A receiving tray 24 that receives the pigment p2 discharged from the inside of the pipe 21 is disposed below the outlet 21B of the pipe 21.

  In the coating apparatus 20, the CDV material m is vaporized by the vaporizer 22, and the vaporized vapor of the CDV material m is carried by the carrier gas that flows from the upstream side into the pipe line 23. To be supplied.

  In this state, the heated granular pigment p2 is charged from the inlet 21A at the upper end of the pipe 21.

  Then, in the pipe 21, the vapor of the CDV material m is sprayed on the particulate pigment p2 falling in the pipe 21, and the surface of the pigment p2 is caused by the fluorescent material that is the CDV material as described above. A phosphor thin film is formed, and then dropped into the tray 24 from the discharge port 21B.

It is sectional drawing which shows the Example in embodiment of this invention. It is the elements on larger scale of the structure of the fluorescent substance layer of the Example. In the same Example, it is a graph which shows the brightness | luminance of a red fluorescent substance layer, and the reflectance of external light. In the Example, it is a graph which shows the brightness | luminance of a green fluorescent substance layer, and the reflectance of external light. In the same Example, it is a graph which shows the brightness | luminance and reflectance of external light of another green fluorescent substance layer. In the same Example, it is a graph which shows the brightness | luminance of a blue fluorescent substance layer, and the reflectance of external light. In the same Example, it is a graph which shows the brightness | luminance and reflectance of external light of another blue fluorescent substance layer. It is a schematic block diagram which shows an example of the coating device of the fluorescent substance thin film to the pigment in the Example. It is a schematic block diagram which shows the other example of the coating apparatus of the fluorescent substance thin film to the pigment in the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Front glass substrate 4 ... Back glass substrate 7 ... Phosphor layer p1 ... Phosphor particle p2 ... Pigment (non-light emitting material, light absorbing material)
f ... phosphor thin film C ... discharge cell X, Y ... row electrode D ... column electrode

Claims (10)

In a display device including a phosphor layer that generates visible light when excited by an excitation source,
The phosphor layer is formed by mixing phosphor particles formed of a fluorescent material that emits visible light of a predetermined color when excited by an excitation source and non-luminescent particles formed of a non-luminescent material. ,
The surface of the non-luminous particles is covered with a phosphor thin film formed of a phosphor material,
A display device characterized by that.   The display device according to claim 1, wherein the non-light emitting material is a light absorbing material.   The display device according to claim 1, wherein the non-light emitting material is a pigment.   The display device according to claim 1, wherein a color of the non-light emitting material forming the non-light emitting particles is the same color as a light emitting color of the phosphor particles constituting the same phosphor layer together with the non-light emitting particles.   2. The display device according to claim 1, wherein an emission color of the phosphor thin film covering the non-light emitting particles is the same color as a light emission color of the phosphor particles constituting the same phosphor layer together with the non-light emitting particles.   The display device according to claim 1, wherein an optical film thickness of the phosphor thin film is set to an integral multiple of a half wavelength of an emission wavelength from the phosphor thin film.   The display device according to claim 1, wherein the non-luminescent material is a white non-luminescent material, and an optical film thickness of the phosphor thin film is set to an integral multiple of a half wavelength of an emission wavelength from the phosphor thin film. .   The display device according to claim 1, wherein the excitation source is a vacuum ultraviolet ray.   The display device according to claim 1, wherein the display device is a gas discharge display device.   The display device according to claim 9, wherein the gas discharge display device is a plasma display panel.

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