WO2009118806A1 - Phosphor mixture and plasma display panel using the phosphor mixture - Google Patents

Phosphor mixture and plasma display panel using the phosphor mixture Download PDF

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Publication number
WO2009118806A1
WO2009118806A1 PCT/JP2008/055446 JP2008055446W WO2009118806A1 WO 2009118806 A1 WO2009118806 A1 WO 2009118806A1 JP 2008055446 W JP2008055446 W JP 2008055446W WO 2009118806 A1 WO2009118806 A1 WO 2009118806A1
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Prior art keywords
phosphor
inorganic pigment
particles
display panel
plasma display
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PCT/JP2008/055446
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French (fr)
Japanese (ja)
Inventor
福田　晋也
別井　圭一
小坂　忠義
長谷川　実
井上　一
瀬尾　欣穂
智也 三澤
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株式会社 日立製作所
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Priority to PCT/JP2008/055446 priority Critical patent/WO2009118806A1/en
Publication of WO2009118806A1 publication Critical patent/WO2009118806A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J11/00—Gas-filled discharge tubes with alternating current induction of the discharge, e.g. alternating current plasma display panels [AC-PDP]; Gas-filled discharge tubes without any main electrode inside the vessel; Gas-filled discharge tubes with at least one main electrode outside the vessel
    • H01J11/10—AC-PDPs with at least one main electrode being out of contact with the plasma
    • H01J11/12—AC-PDPs with at least one main electrode being out of contact with the plasma with main electrodes provided on both sides of the discharge space
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J11/00—Gas-filled discharge tubes with alternating current induction of the discharge, e.g. alternating current plasma display panels [AC-PDP]; Gas-filled discharge tubes without any main electrode inside the vessel; Gas-filled discharge tubes with at least one main electrode outside the vessel
    • H01J11/20—Constructional details
    • H01J11/34—Vessels, containers or parts thereof, e.g. substrates
    • H01J11/42—Fluorescent layers

Definitions

  • the present invention relates to a phosphor technology, and more particularly, to a technology effective when applied to a phosphor used in a display device that displays an image by exciting the phosphor with light, such as a plasma display panel.
  • PDP plasma display panel
  • the PDP has a front substrate and a rear substrate, and a discharge space in which a discharge gas is sealed is formed between the front substrate and the rear substrate.
  • a desired image is displayed by generating a discharge in the discharge space and exciting the phosphor with vacuum ultraviolet rays generated at this time.
  • the PDP has phosphors that emit red (R), green (G), and blue (B) colors, and these phosphors are generally white. For this reason, when the PDP is observed in a bright environment, there is a problem that external light incident on the PDP is reflected with a high reflectance, and the contrast (bright room contrast) is lowered.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 10-152680 (Patent Document 1) and Japanese Patent Application Laid-Open No. 11-1331059 (Patent Document 2) disclose a technique of mixing a pigment in a predetermined weight ratio with a phosphor.
  • Patent Document 3 Japanese Patent Application Laid-Open No. 9-40945
  • Patent Document 4 Japanese Patent Application Laid-Open No. 10-269952
  • Patent Document 5 Japanese Patent Application Laid-Open No. 11-43670
  • Patent Document 6 discloses a technique of dividing a region where a phosphor layer portion is formed and containing a pigment at a different content in each of the divided regions. ing. Japanese Patent Laid-Open No. 10-152680 Japanese Patent Laid-Open No. 11-131059 Japanese Patent Laid-Open No. 9-40945 Japanese Patent Laid-Open No. 10-269952 JP 11-43670 A JP 2007-80556 A
  • Patent Document 2 when 5 wt% of the pigment is added, the display brightness of the PDP is reduced by about 50% compared to the case where the pigment is not mixed with the phosphor.
  • the present invention has been made in view of the above problems, and a purpose thereof is a technique capable of reducing the reflectance of external light while suppressing a decrease in display luminance of a display device using a phosphor such as PDP. Is to provide.
  • a phosphor mixture used for forming a phosphor part included in a display device such as a PDP in an embodiment of the present invention is a mixture of phosphor particles that emit light when excited by excitation light, and the phosphor particles.
  • the inorganic pigment particles have a crystal matrix having a band gap larger than the energy of the excitation light and an impurity level formed in the band gap, and the impurities The energy width from the HOMO level of the level to the conduction band of the crystal matrix is different from the energy of the excitation light.
  • a PDP will be described as an example of a display device using a phosphor.
  • FIG. 1 is an enlarged perspective view of an essential part of the PDP according to the present embodiment.
  • the PDP 1 has a front substrate structure (first substrate structure) 11 and a back substrate structure (second substrate structure) 12.
  • the front substrate structure 11 and the back substrate structure 12 are overlapped with each other so as to face each other, and have a discharge space 24 therebetween. That is, the front substrate structure 11 and the back substrate structure 12 are disposed to face each other with the discharge space 24 interposed therebetween.
  • the front substrate structure 11 has a display surface of the PDP 1 and has a front substrate 13 mainly made of glass.
  • a plurality of X electrodes (sustain electrodes, sustain electrodes) 14 and Y electrodes (scan electrodes, scan electrodes) 15 which are display electrodes of the PDP 1 are formed on the inner surface side of the front substrate 13.
  • the X electrode 14 and the Y electrode 15 constitute a pair of display electrodes for performing a sustain discharge (display discharge, sustain discharge), and are alternately arranged so as to extend in a strip shape along the row direction DX, for example. ing.
  • the pair of X electrode 14 and Y electrode 15 form a display line in the row direction DX in the PDP 1.
  • FIG. 1 two pairs of the X electrode 14 and the Y electrode 15 are shown in an enlarged manner.
  • the PDP 1 has a plurality of X electrodes 14 and Y electrodes 15 according to the number of display lines. Yes.
  • the X electrode 14 and the Y electrode 15 are generally composed of, for example, an X transparent electrode 14a and a Y transparent electrode 15a made of a transparent electrode material such as ITO (Indium Tin Oxide) or SnO 2, and, for example, Ag (silver), Au X bus electrode (metal electrode part) 14b made of (gold), Al (aluminum), Cu (copper), Cr (chromium), or a laminate thereof (for example, a laminate of Cr / Cu / Cr), Y bus It is comprised with the electrode (metal electrode part) 15b.
  • ITO Indium Tin Oxide
  • SnO 2 Tin Oxide
  • Ag silver
  • Au X bus electrode (metal electrode part) 14b made of (gold), Al (aluminum), Cu (copper), Cr (chromium), or a laminate thereof (for example, a laminate of Cr / Cu / Cr), Y bus It is comprised with the electrode (metal electrode part) 15b.
  • FIG. 1 shows the X transparent electrode 14a and the Y transparent electrode 15a extending in a strip shape, but the electrode structure of the X transparent electrode 14a and the Y transparent electrode 15a is not limited to this.
  • the position where the shortest distance between the pair of electrodes (referred to as a discharge gap) overlaps with the X bus electrode 14b and the Y bus electrode 15b so as to approach the cell. It is good also as a structure which forms a protrusion part in the direction which respectively opposes.
  • the electrode structure may be a so-called ALIS (AlternateternLighting of Surface Method).
  • Electrodes X electrodes 14, Y electrodes 15
  • the dielectric layer 17 is formed on the second surface 13b side of the front substrate 13, and a third surface 17a facing the second surface 13a and a fourth surface positioned on the opposite side of the third surface 17a. And a surface 17b.
  • a protective film 18 made of a metal oxide such as MgO is formed on the surface of the dielectric layer 17.
  • the protective film 18 is formed so as to cover one surface of the dielectric layer 17.
  • the back substrate structure 12 has a back substrate (substrate) 19 mainly made of glass.
  • a plurality of address electrodes (second electrodes) 20 are formed on the surface (inner surface) of the rear substrate 19 facing the front substrate structure 11.
  • Each address electrode 20 is formed so as to extend along a column direction DY intersecting (substantially orthogonal to) the direction in which the X electrode 14 and the Y electrode 15 extend.
  • the address electrodes 20 are arranged with a predetermined arrangement interval so as to be substantially parallel to each other.
  • the address electrode 20 is made of, for example, Ag, Au, Al, Cu, Cr, or a laminate thereof (for example, a laminate of Cr / Cu / Cr). Can do.
  • the address electrode 20 and the Y electrode 15 formed on the front substrate structure 11 constitute an electrode pair for performing address discharge, which is discharge for selecting lighting / non-lighting of the cell 25. That is, the Y electrode 15 has both a function as a sustain discharge electrode and a function as an address discharge electrode (scanning electrode).
  • Each cell 25 is configured to correspond to the intersection of the address electrode 20 and the pair of X electrode 14 and Y electrode 15. That is, the cell 25 is formed at each intersection of the display electrode pair (a pair of the X electrode 14 and the Y electrode 15) and the address electrode 20.
  • Each cell 25 emits red (R), green (G), and blue (B) visible light by sustain discharge, and a pixel (pixel) is configured by the set of each R, G, and B cell 25.
  • the address electrode 20 is covered with a dielectric layer 21.
  • a plurality of partition walls 22 extending in the thickness direction of the back substrate structure 12 are formed on the dielectric layer 21.
  • the barrier ribs 22 are formed to extend in a line along the column direction DY in which the address electrodes 20 extend.
  • the front substrate structure 11 and the rear substrate structure 12 are fixed in a state where the surface on which the protective film 18 is formed and the surface on which the partition wall 22 is formed face each other.
  • a position on the plane of the partition wall 22 is disposed between the adjacent address electrodes 20.
  • a phosphor portion that is excited by vacuum ultraviolet rays and generates visible light of each color of R, G, and B. 23r, 23g, and 23b are formed.
  • each discharge space 24 is filled with a gas such as a rare gas called a discharge gas at a predetermined pressure.
  • a gas such as a rare gas called a discharge gas at a predetermined pressure.
  • a mixed gas such as Xe-Ne whose Xe partial pressure ratio is adjusted to several to several tens of percent is used, and the pressure of the gas to be filled is 350 to 500 torr (about 47 to 67 kPa), for example. It can be.
  • the PDP 1 generates a discharge (sustain discharge) for each cell 25 in the discharge space 24, and is generated by the discharge (specifically, generated when an ion excited by the discharge transitions to a ground state).
  • the R, G, B phosphor portions 23 are excited to emit light.
  • vacuum ultraviolet rays of 147 nm and 172 nm are generated as excitation light for exciting the phosphor parts 23.
  • the wavelength of this vacuum ultraviolet ray (particularly the vacuum ultraviolet ray from the excimer) may have a certain range, but falls within the range of 147 nm to 180 nm.
  • FIG. 1 shows an example in which the partition wall 22 is formed in a strip shape
  • the arrangement of the partition wall is not limited to this.
  • a second barrier rib extending along the row direction DX may be arranged to partition the discharge space 24 in a grid pattern.
  • the discharge space 24 is partitioned into a box shape for each cell 25 by the barrier ribs 22 and the second barrier ribs, such a barrier rib structure is called a box structure.
  • 1 shows an example in which the address electrode 20 is formed on the back substrate structure 12, the address electrode 20 can also be formed on the front substrate structure 11.
  • FIG. 2 is an explanatory diagram showing the relationship between external light incident on the PDP and display light from the PDP.
  • the structure of the PDPs 1 and 2 is shown as a simplified model so that the relationship between the external light and the display light can be easily understood.
  • PDP1 and PDP2 are display devices whose display light P has emission luminance I i and reflectance R i , and a filter F having transmittance T i is disposed on the display surface (front surface) side.
  • a filter F having transmittance T i is disposed on the display surface (front surface) side.
  • the display brightness of the PDP 1 (the brightness seen by the observer) is advantageous in the inverse proportion of the reflectance. That is, if the luminance I 0 of the external light L is constant, the bright room contrast C i can be improved as the light emission luminance I i is increased and the reflectance R i is decreased.
  • the PDP 1 shown in FIG. 1 has a structure in which a front substrate structure 11 and a rear substrate structure 12 disposed opposite to each other are overlapped.
  • a member having a large influence on the reflectance of external light is the phosphor portion 23 of the back substrate structure 12.
  • a means for reducing the reflectance of the back substrate structure 12 on which the phosphor portion 23 is formed will be described.
  • FIG. 3 is an explanatory diagram showing a simplified model for explaining the effect of reducing the reflectivity of the structure of the back substrate structure of the PDP shown in FIG.
  • a phosphor portion 23 is formed on the back substrate 19 included in the back structure 12. This phosphor portion 23 is arranged with phosphor portions 23r, 23g, and 23b that emit visible light of red, green, and blue, respectively.
  • the white phosphor portion 23 and the back substrate 19 are in a completely reflective state (a state where the reflectance is 100%).
  • the reflectivity of the back substrate structure 12 is 1 (100%). Further, assuming that the luminance of visible light emitted from the phosphor portion 23 is I, all the light emission from the phosphor portion 23 is also reflected, and thus the emission luminance of the rear substrate structure 12 is also I.
  • the color tone of the phosphor part 23 is the same color tone as the visible light emitted from each phosphor part 23r, 23g, 23b will be considered.
  • the average reflectance can be reduced to 1/3 (about 33%).
  • the emission luminance of the rear substrate structure 12 is ideally set to I because all visible light emitted from the phosphor portion 23 is reflected.
  • the display luminance of the back substrate structure 12 is obtained by setting the color tone of the phosphor portion 23 to the same color tone as the visible light emitted by the phosphor portions 23r, 23g, and 23b. (Luminance as viewed from the observer) can be made three times as high (as compared to the case where the phosphor portion 23 is white).
  • a phosphor that is a mixture of inorganic pigment particles having red, green, and blue color tones and substantially white phosphor particles is used as the phosphor portion 23. It will be.
  • the inorganic pigment particles absorb the excitation light irradiated on the phosphor particles.
  • the penetration length to the substance is an excitation source that is equal to or less than the average particle diameter of the inorganic pigment particles, such as vacuum ultraviolet rays that are the excitation source of PDP1
  • absorption of excitation energy by the inorganic pigment particles occurs, This loss is one of the causes that cause a decrease in the light emission luminance of the phosphor portion 23.
  • the excitation light reaches the phosphor particles, visible light emitted from the phosphor particles is absorbed by the inorganic pigment particles covering the surface. As a result, the light emission luminance of the phosphor portion 23 is lowered.
  • the surface of the inorganic pigment particles is covered with the phosphor particles, it is possible to suppress a decrease in emission luminance.
  • the thickness of the phosphor particle layer formed on the surface of the inorganic pigment particle is too thick, scattering of the external light L irradiated to the phosphor particle layer occurs, and the reflectance increases due to this scattering. To do.
  • the average particle diameter of the phosphor particles is 1 to 5 ⁇ m, the reflectance increases by 10% or more with only the reflection component resulting from the scattering. For this reason, the reflectance of the phosphor portion 23 cannot be sufficiently reduced, and as a result, the above-described effect of improving the display luminance cannot be obtained.
  • the present inventor has studied a technique for reducing the reflectance of outside light while suppressing a decrease in light emission luminance or display luminance, and a band gap larger than the energy of excitation light and impurities formed in the band gap. And a phosphor part by mixing inorganic pigment particles having different energy widths from the HOMO level of the impurity level to the conduction band of the crystal matrix and the energy of the excitation light with the phosphor particles.
  • the structure which forms 23 was found. Hereinafter, a specific configuration of the phosphor portion 23 will be described.
  • FIG. 4 is an enlarged cross-sectional view of the main part showing the detailed configuration of the phosphor part of the present embodiment
  • FIG. 5 is a band diagram showing the energy band of the inorganic pigment constituting the phosphor part shown in FIG.
  • the structure of the phosphor portion 23 shown in FIG. 4 is a structure common to the phosphor portion 23r for red, the phosphor portion 23g for green, and the phosphor portion 23b for blue.
  • the phosphor portion 23 includes phosphor particles (phosphor) 31 and inorganic pigment particles (inorganic pigment) 32 mixed with the phosphor particles 31.
  • the phosphor particles 31 and the inorganic pigment particles 32 are shown as particles having a circular cross-sectional shape, but the structures of the phosphor particles 31 and the inorganic pigment particles 32 are the same. It is not limited to.
  • the phosphor particles 31 and the inorganic pigment particles 32 may have a flat cross-sectional shape. Further, for example, there are various heating processes in the manufacturing process of the PDP 1 (see FIG. 1).
  • the phosphor part 23 may be a mixture of a phosphor and an inorganic pigment, and may have a structure in which a part of each particle is fixed and integrated.
  • the material constituting the phosphor particles 31 is, for example, (Y, Gd) 2 O 3 : Eu for the phosphor particles 31r for red, and Zn 2 SiO 4 : Mn, YBO 3 for the phosphor particles 31g for green.
  • BaMgAl 10 O 17 : Eu 2+ can be exemplified as the phosphor particles 31b for: Tb and blue.
  • the phosphor particles 31r, 31g, and 31b emit red, green, and blue light, respectively, by being excited by excitation light that is an excitation source (in this embodiment, vacuum ultraviolet rays having wavelengths of 147 nm and 172 nm). To do.
  • the inorganic pigment particles 32 include, for example, ruby (Al 2 O 3 : Cr) for red inorganic pigment particles 32r, green sapphire (Al 2 O 3 : Fe) for blue inorganic pigment particles 31g, and blue Blue sapphire (Al 2 O 3 : Ti) is used for the inorganic pigment particles 32b. All of these are crystal bodies called corundum, in which 3d transition metals Cr, Fe (iron), and Ti (titanium) are introduced as impurities into alumina (Al 2 O 3 ), which is a crystal base. .
  • alumina which is the crystal matrix of the inorganic pigment particles 32, has a band gap W1 of about 10 eV between the conduction band CB and the valence band VB.
  • vacuum ultraviolet rays having wavelengths of 147 nm and 172 nm, which are excitation sources of PDP1 are about 8.4 eV and 7.2 eV, respectively, and the band gap W1 of alumina is larger than the energy of the excitation light.
  • the above-described light shielding of the excitation light by the inorganic pigment particles constituting the phosphor portion 23 is such that the inorganic pigment particles absorb the energy of the excitation light (electrons in the valence band VB are excited by the excitation light and transition to the conduction band CB. Generated). Since alumina used in this embodiment has a band gap W1 larger than the energy of excitation light, electrons in the valence band VB do not transition to the conductor CB even when irradiated with excitation light, and the absorption rate of excitation light is high. Low. That is, it is transparent to vacuum ultraviolet rays that are excitation light.
  • spinel MgAl 2 O 4
  • alumina is more sensitive to light having a wavelength of 147 nm and 172 nm (vacuum ultraviolet light) than excitation light. Since the transmittance is high, it is more preferable.
  • the reflectance of the phosphor portion 23 with respect to the external light is determined by the visible light absorption characteristics of the inorganic pigment particles 32.
  • the visible light absorption characteristics of the inorganic pigment 32 are determined as follows. When a 3d transition metal element is introduced into alumina, the 3d transition metal ions are replaced with alumina Al 3+ ions. For example, when Cr is introduced as a 3d transition element, Cr 3+ ions are replaced with some Al 3+ ions, and at the substituted sites, as shown in FIG. 5 between the band gap W1 of alumina, which is the crystal matrix. Impurity levels are formed.
  • Energy width W2 of the lower t 2 g orbitals and high e g orbitals energy of this energy is a factor which determines the visible light absorption properties of the inorganic pigment particles 32.
  • the energy width W2 is about 2.3 eV, and when it is irradiated with external light (white light for simplicity), visible light in the wavelength range of purple and yellow-green has low energy. It is absorbed as the transition energy of electrons clogged in the t 2g orbital (as a result, ruby exhibits a complementary color, red). For this reason, since external light is absorbed by the inorganic pigment particles 32, the reflectance of the PDP 1 (see FIG. 1) can be reduced.
  • the impurities are Sc (scandium), V (vanadium), Mn (manganese), Co (cobalt), Ni (nickel), Cu (copper), Zn (zinc), etc. can also be introduced.
  • Two or more 3d transition metals can also be introduced. For example, some sapphires exhibiting a blue color tone have Fe and Ti introduced as impurities.
  • the impurity level includes a defect level formed in alumina which is a crystal base. When this defect level has a visible light absorption characteristic, external light is emitted in the same manner as when impurities are introduced. Can be absorbed.
  • any one or two or more impurities of Cr, Fe, or Ti having red, green, and blue color tones having visible light absorption characteristics in the color tone complementary to the emission color of the phosphor particles 31 are contained. It is particularly preferable to introduce impurity levels.
  • the impurity level formed by the impurities introduced into the alumina affects not only the absorption characteristic of visible light but also the absorption characteristic of vacuum ultraviolet light that is excitation light. More specifically, from the energy level of the highest energy orbital (HOMO) occupied by electrons among the low energy t 2g orbitals (hereinafter referred to as the HOMO level), the crystal matrix of alumina. When the energy width W3 to the conduction band CB is equal to the energy of vacuum ultraviolet light as excitation light, electrons occupying the orbit of the HOMO level absorb the vacuum ultraviolet light as excitation energy and transition to the conduction band CB of alumina.
  • HOMO highest energy orbital
  • the crystal matrix of alumina When the energy width W3 to the conduction band CB is equal to the energy of vacuum ultraviolet light as excitation light, electrons occupying the orbit of the HOMO level absorb the vacuum ultraviolet light as excitation energy and transition to the conduction band CB of alumina.
  • the energy width W3 and the energy of vacuum ultraviolet rays need to be different.
  • the energy width W4 from the valence band VB of alumina to the HOMO level is about 0.9 eV
  • the energy width W3 is 9.1 eV.
  • the energy width W3 is larger than the energy of the excitation light, the absorption of the excitation light due to the impurity level can be prevented or suppressed.
  • the energy width W4 from the band VB to the HOMO level is smaller than 1 eV. Therefore, since the energy width W3 is 9 eV or more, which is larger than the energy of the excitation light, absorption of the excitation light due to the impurity level can also be prevented.
  • the crystal matrix of the inorganic pigment particles 32 mixed with the phosphor particles 31 is alumina having a band gap W1 larger than the energy of the excitation light, thereby absorbing the excitation light. Can be prevented or suppressed.
  • an impurity level impurity level having visible light absorption characteristics
  • the energy width W3 from the HOMO level of the impurity level to the conduction band of the crystal base different from the energy of the excitation light, the transition of electrons from the HOMO level to the conduction band is prevented or suppressed. be able to. Accordingly, absorption of excitation light due to the impurity level can be prevented or suppressed.
  • the particle diameter of the phosphor particles is generally about 1 to 10 ⁇ m.
  • the particle diameter of general inorganic pigment particles is 1 ⁇ m or less, typically 5 to 500 nm so that they can be dispersed even when mixed in a liquid such as ink. That is, the particle diameter of the inorganic pigment particles is generally smaller than the particle diameter of the phosphor particles.
  • the particle size of the red pigment described in Patent Document 1 is about 100 nm.
  • the specific surface area of the green pigment (manufactured by Nissei Kagaku Kogyo Co., Ltd .: “TM Green # 3340”) is 100 m 2 / g, and the particle diameter is about 10 to 20 nm.
  • the particle diameter of the blue pigment (Asahi Sangyo Co., Ltd .: “Asahi Super Blue CR”) is about 200 nm.
  • the particle diameter (average particle diameter) of the inorganic pigment particles 32 is larger than the particle diameter (average particle diameter) of the phosphor particles 31.
  • the effect obtained by making the particle diameter of the inorganic pigment particles 32 larger than the particle diameter (average particle diameter) of the phosphor particles 31 will be described.
  • the alumina used as the crystal matrix of the inorganic pigment particles 32 in the present embodiment has a band gap W1 (see FIG. 5) of 10 eV, which is larger than the energy in the visible light region. Therefore, alumina itself is transparent not only for excitation light but also for visible light.
  • the inorganic pigment particles 32 obtain visible light absorption characteristics by, for example, introducing impurities into the band gap W1 to form impurity levels.
  • the inorganic pigment particles 32 used in the present embodiment have a lower amount of visible light absorption per unit surface area than the above-described generally used inorganic pigments.
  • the particle diameter (average particle diameter) of the inorganic pigment particles 32 is larger than the particle diameter (average particle diameter) of the phosphor particles 31.
  • the manufacturing process of the PDP 1 is roughly divided into a process of preparing the front substrate structure 11 and the rear substrate structure 12 shown in FIG. 1, and the front substrate structure 11 and the rear substrate structure 12 facing each other through the discharge space 24. And arranging and assembling.
  • the step of forming the phosphor portion 23 in the discharge space 24 formed in the back substrate structure 12 will be described in detail.
  • FIG. 6 is an explanatory diagram showing a manufacturing flow of the phosphor portion 23 included in the PDP of the present embodiment.
  • the phosphor part 23 shown in FIG. 1 is formed as follows, for example.
  • step S1 First, phosphor particles 31 and inorganic pigment particles 32 having an average particle diameter larger than the average particle diameter of the phosphor particles 31 are prepared in the preparation step shown in step S1. In this step, impurity levels are formed in the band gap W1 (see FIG. 5) of the inorganic pigment particles 32.
  • step S2 the inorganic pigment particles 32 and the phosphor particles 31 are mixed in the mixing step shown in step S2 to obtain a phosphor mixture 33.
  • the inorganic pigment particles 32 and the phosphor particles 31 are mixed so that they are dispersed. Therefore, various mixing methods can be used as long as each particle can be dispersed and mixed. For example, mixing can be performed using a mixer or the like. Further, for example, the phosphor particles 31 and the inorganic pigment particles 32 can be dispersed and mixed in the solution.
  • the surface areas of the inorganic pigment particles 32 and the phosphor particles 31 to be added are determined. It is preferable to determine the addition amount by measuring the sum.
  • the phosphor parts 23r, 23g, and 23b include different inorganic pigment particles 32r, 32g, and 32b (see FIG. 4), the red phosphor particles 31r and the red inorganic pigment are used. Particles 32r, green phosphor particles 31g and green inorganic pigment particles 32g, and blue phosphor particles 31b and blue inorganic pigment particles 32b are mixed separately.
  • a phosphor paste 34 is obtained by mixing the phosphor mixture 33 in a vehicle composed of an organic solvent, an organic binder agent, and the like in the pasting step shown in step S3.
  • the phosphor mixture 33 may be dispersed in the phosphor paste 34, and the mixing method is not particularly limited.
  • step S4 the phosphor paste 34 is applied to the region where the phosphor part 23 shown in FIG. 1 is formed. Specifically, a plurality of address electrodes 20 are formed in advance on the surface of the back substrate 19 shown in FIG. 3, then a dielectric layer 21 is formed so as to cover the address electrodes 20, and then the surface of the dielectric layer 21 is formed. The barrier ribs 22 that define the plurality of discharge spaces 24 are formed. In step S4, the phosphor paste 34 is applied to the discharge space 24 (bottom surface and side wall) partitioned by the barrier ribs 22 by, for example, a screen printing method or a dispensing method.
  • the phosphor pastes 34 for red, green, and blue are separately applied.
  • the phosphor part 23 obtained in this way is formed in a state where the primary particles of the inorganic pigment particles 32 and the phosphor particles 31 are dispersed, and therefore when set in the mixing step shown in step S2.
  • the surface area ratio is reflected.
  • the surface areas of phosphor particles 31 and inorganic pigment particles 32 are measured, and the amount of each particle added is determined.
  • the reflectance with respect to the external light of the fluorescent substance part 23 can be reduced stably.
  • the display device can be widely applied to any display device that displays an image by exciting a phosphor with light.
  • the present invention can be applied to a display device such as a PDP that displays an image by exciting a phosphor with light.

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Abstract

A phosphor mixture composed of phosphor particles, which emit light upon excitation with excitation light, and inorganic pigment particles mixed in the phosphor particles, is used in the formation of a phosphor part in a display device such as PDP. The inorganic pigment particle comprises a crystal matrix having a band gap (W1) larger than the energy of excitation light and an impurity level formed within the band gap (W1). The energy width (W3) from the HOMO level in the impurity level to the conduction band (CB) of the crystal matrix is rendered different from the energy of the excitation light. According to the above constitution, external light can be absorbed while preventing a lowering in luminescence brightness caused by the absorption of the excitation light, and, thus, the roomlight contrast of the display device can be improved.

Description

蛍光体混合物およびこれを用いたプラズマディスプレイパネルPhosphor mixture and plasma display panel using the same
　本発明は、蛍光体の技術に関し、特に、プラズマディスプレイパネルなど光で蛍光体を励起して画像を表示する表示装置に用いる蛍光体に適用して有効な技術に関する。 The present invention relates to a phosphor technology, and more particularly, to a technology effective when applied to a phosphor used in a display device that displays an image by exciting the phosphor with light, such as a plasma display panel.
　蛍光体の発光を利用した表示装置として、プラズマディスプレイパネル（ＰＤＰ；Plasma Display Panel）がある。 There is a plasma display panel (PDP) as a display device using light emission of a phosphor.
　ＰＤＰは、前面基板と背面基板とを有し、これらの基板の間に放電ガスを封入した放電空間が前面基板と背面基板との間に形成される。この放電空間で放電を発生させ、この際に発生する真空紫外線で蛍光体を励起させることで所望の画像が表示される。 The PDP has a front substrate and a rear substrate, and a discharge space in which a discharge gas is sealed is formed between the front substrate and the rear substrate. A desired image is displayed by generating a discharge in the discharge space and exciting the phosphor with vacuum ultraviolet rays generated at this time.
　ＰＤＰは、赤（Ｒ）、緑（Ｇ）、青（Ｂ）の各色を発光する蛍光体を有しているが、これらの蛍光体は一般に白色である。このため、ＰＤＰを明るい環境で観察すると、ＰＤＰに入射される外光が高い反射率で反射され、コントラスト（明室コントラスト）が低下するという課題がある。 The PDP has phosphors that emit red (R), green (G), and blue (B) colors, and these phosphors are generally white. For this reason, when the PDP is observed in a bright environment, there is a problem that external light incident on the PDP is reflected with a high reflectance, and the contrast (bright room contrast) is lowered.
　この外光の反射を抑制するため、白色の蛍光体を無機顔料と混合する技術が提案されている。 In order to suppress this reflection of external light, a technique of mixing a white phosphor with an inorganic pigment has been proposed.
　例えば、特開平１０－１５２６８０号公報（特許文献１）や特開平１１－１３１０５９号公報（特許文献２）には、蛍光体に所定の重量割合で顔料を混合する技術が開示されている。 For example, Japanese Patent Application Laid-Open No. 10-152680 (Patent Document 1) and Japanese Patent Application Laid-Open No. 11-1331059 (Patent Document 2) disclose a technique of mixing a pigment in a predetermined weight ratio with a phosphor.
　また、例えば、特開平９－４０９４５号公報（特許文献３）、特開平１０－２６９９５２号公報（特許文献４）、特開平１１－４３６７０号公報（特許文献５）には、蛍光体粒子の表面に顔料を被覆させる技術が開示されている。 Further, for example, in Japanese Patent Application Laid-Open No. 9-40945 (Patent Document 3), Japanese Patent Application Laid-Open No. 10-269952 (Patent Document 4), and Japanese Patent Application Laid-Open No. 11-43670 (Patent Document 5), A technique for coating a pigment with a pigment is disclosed.
　また、例えば、特開２００７－８０５５６号公報（特許文献６）には、蛍光体層部を形成する領域を区分して、この区分した領域毎に異なる含有率で顔料を含有させる技術が開示されている。
特開平１０－１５２６８０号公報 特開平１１－１３１０５９号公報 特開平９－４０９４５号公報 特開平１０－２６９９５２号公報 特開平１１－４３６７０号公報 特開２００７－８０５５６号公報 Further, for example, Japanese Patent Application Laid-Open No. 2007-80556 (Patent Document 6) discloses a technique of dividing a region where a phosphor layer portion is formed and containing a pigment at a different content in each of the divided regions. ing.
Japanese Patent Laid-Open No. 10-152680 Japanese Patent Laid-Open No. 11-131059 Japanese Patent Laid-Open No. 9-40945 Japanese Patent Laid-Open No. 10-269952 JP 11-43670 A JP 2007-80556 A
　しかしながら、蛍光体に無機顔料を混合すると、ＰＤＰの表示輝度が低下するという課題がある。この理由は、第１には、放電により発生した真空紫外線が無機顔料に吸収されて減衰し、発光輝度が低下するためである。また、第２には、真空紫外線により励起され、蛍光体から発光された可視光が無機顔料に吸収されて減衰するためである。 However, when an inorganic pigment is mixed with the phosphor, there is a problem that the display brightness of the PDP is lowered. This is because, firstly, the vacuum ultraviolet rays generated by the discharge are absorbed by the inorganic pigment and attenuated, and the light emission luminance is lowered. The second reason is that visible light excited by vacuum ultraviolet rays and emitted from the phosphor is absorbed by the inorganic pigment and attenuated.
　例えば、前記特許文献２において、顔料を５ｗｔ％添加した場合には、ＰＤＰの表示輝度は蛍光体に顔料を混合しないものと比較して約５０％程度低下する。 For example, in Patent Document 2, when 5 wt% of the pigment is added, the display brightness of the PDP is reduced by about 50% compared to the case where the pigment is not mixed with the phosphor.
　このように、蛍光体に無機顔料を混合すると、ＰＤＰの表示輝度が低下するという課題は解決されておらず、安定的にＰＤＰの明室コントラストを向上させるまでには至っていない。このため、蛍光体に無機顔料を混合する構成は、種々検討はされているものの、未だ実用化には至っていない。 Thus, when the inorganic pigment is mixed with the phosphor, the problem that the display brightness of the PDP is lowered has not been solved, and the bright room contrast of the PDP has not been improved stably. For this reason, although the structure which mixes an inorganic pigment with fluorescent substance is variously examined, it has not yet reached practical use.
　本発明は、上記課題に鑑みてなされたものであり、その目的は、ＰＤＰなど蛍光体を用いた表示装置の表示輝度の低下を抑制しつつ、外光の反射率を低下させることができる技術を提供することにある。 The present invention has been made in view of the above problems, and a purpose thereof is a technique capable of reducing the reflectance of external light while suppressing a decrease in display luminance of a display device using a phosphor such as PDP. Is to provide.
　本発明の前記ならびにその他の目的と新規な特徴は、本明細書の記述および添付図面から明らかになるであろう。 The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.
　本願において開示される発明のうち、代表的なものの概要を簡単に説明すれば、次のとおりである。 Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.
　すなわち、本発明の一実施の形態におけるＰＤＰなどの表示装置が有する蛍光体部の形成に用いる蛍光体混合物は、励起光で励起されることにより発光する蛍光体粒子と、前記蛍光体粒子と混合される無機顔料粒子とを有し、前記無機顔料粒子は、前記励起光のエネルギーよりも大きいバンドギャップと、前記バンドギャップ内に形成された不純物準位とを有する結晶母体を有し、前記不純物準位のＨＯＭＯ準位から、前記結晶母体の伝導帯までのエネルギー幅が前記励起光のエネルギーと異なるものとするものである。 That is, a phosphor mixture used for forming a phosphor part included in a display device such as a PDP in an embodiment of the present invention is a mixture of phosphor particles that emit light when excited by excitation light, and the phosphor particles. The inorganic pigment particles have a crystal matrix having a band gap larger than the energy of the excitation light and an impurity level formed in the band gap, and the impurities The energy width from the HOMO level of the level to the conduction band of the crystal matrix is different from the energy of the excitation light.
　本願において開示される発明のうち、代表的なものによって得られる効果を簡単に説明すれば以下のとおりである。 Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.
　すなわち、表示装置の表示輝度の低下を抑制しつつ、外光の反射率を低下させることができる。 That is, it is possible to reduce the reflectance of external light while suppressing a decrease in display brightness of the display device.
本発明の一実施の形態であるＰＤＰの要部を拡大して示す要部拡大組み立て斜視図である。It is a principal part expansion assembly perspective view which expands and shows the principal part of PDP which is one embodiment of this invention. ＰＤＰに入射される外光と表示装置からの表示光との関係を示す説明図である。It is explanatory drawing which shows the relationship between the external light which injects into PDP, and the display light from a display apparatus. 図１に示すＰＤＰが有する背面基板構造体の構造について反射率低減の効果を説明するために単純化したモデルとして示す説明図である。It is explanatory drawing shown as a model simplified in order to demonstrate the effect of a reflectance reduction about the structure of the back substrate structure which PDP shown in FIG. 1 has. 図１に示すの蛍光体部の詳細な構成を示す要部拡大断面図である。It is a principal part expanded sectional view which shows the detailed structure of the fluorescent substance part shown in FIG. 図４に示す蛍光体部を構成する無機顔料のエネルギーバンドを示すバンド図である。It is a band figure which shows the energy band of the inorganic pigment which comprises the fluorescent substance part shown in FIG. 本発明の一実施の形態であるＰＤＰが有する蛍光体部２３の製造フローを示す説明図である。It is explanatory drawing which shows the manufacture flow of the fluorescent substance part 23 which PDP which is one embodiment of this invention has.
　本実施の形態を説明するための全図において同一機能を有するものは同一の符号を付すようにし、その繰り返しの説明は原則として省略する。以下、本発明の実施の形態を図面に基づいて詳細に説明する。 In the drawings for explaining the present embodiment, parts having the same function are given the same reference numerals, and repeated explanation thereof is omitted in principle. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
　なお、本実施の形態では、蛍光体を用いた表示装置の例としてＰＤＰを例に取り上げて説明する。 In this embodiment, a PDP will be described as an example of a display device using a phosphor.
　＜ＰＤＰの基本構造＞
　まず、図１を用いて本実施の形態のＰＤＰの構造の一例について交流面放電型のＰＤＰを例に説明する。図１は本実施の形態のＰＤＰの要部を拡大して示す要部拡大組み立て斜視図である。 <Basic structure of PDP>
First, an example of the structure of the PDP according to the present embodiment will be described with reference to FIG. 1 using an AC surface discharge type PDP as an example. FIG. 1 is an enlarged perspective view of an essential part of the PDP according to the present embodiment.
　図１において、ＰＤＰ１は前面基板構造体（第１基板構造体）１１と背面基板構造体（第２基板構造体）１２とを有している。前面基板構造体１１と背面基板構造体１２とは対向配置された状態で重ね合わされ、その間に放電空間２４を有している。つまり、前面基板構造体１１と背面基板構造体１２とは放電空間２４を介して対向配置されている。 In FIG. 1, the PDP 1 has a front substrate structure (first substrate structure) 11 and a back substrate structure (second substrate structure) 12. The front substrate structure 11 and the back substrate structure 12 are overlapped with each other so as to face each other, and have a discharge space 24 therebetween. That is, the front substrate structure 11 and the back substrate structure 12 are disposed to face each other with the discharge space 24 interposed therebetween.
　前面基板構造体１１はＰＤＰ１の表示面を有し、主にガラスで構成される前面基板１３を有している。前面基板１３の内面側にはＰＤＰ１の表示電極であるＸ電極（維持電極、サステイン電極）１４と、Ｙ電極（走査電極、スキャン電極）１５とがそれぞれ複数形成されている。 The front substrate structure 11 has a display surface of the PDP 1 and has a front substrate 13 mainly made of glass. A plurality of X electrodes (sustain electrodes, sustain electrodes) 14 and Y electrodes (scan electrodes, scan electrodes) 15 which are display electrodes of the PDP 1 are formed on the inner surface side of the front substrate 13.
　Ｘ電極１４およびＹ電極１５は維持放電（表示放電、サステイン放電）を行うための一対の表示電極対を構成し、例えば、行方向ＤＸに沿って帯状に延在するようにそれぞれ交互に配置されている。この一対のＸ電極１４とＹ電極１５とがＰＤＰ１における行方向ＤＸの表示ラインを構成する。なお、図１では、二対のＸ電極１４およびＹ電極１５を拡大して示しているが、ＰＤＰ１は、この表示ラインの行数に応じて複数のＸ電極１４およびＹ電極１５を有している。 The X electrode 14 and the Y electrode 15 constitute a pair of display electrodes for performing a sustain discharge (display discharge, sustain discharge), and are alternately arranged so as to extend in a strip shape along the row direction DX, for example. ing. The pair of X electrode 14 and Y electrode 15 form a display line in the row direction DX in the PDP 1. In FIG. 1, two pairs of the X electrode 14 and the Y electrode 15 are shown in an enlarged manner. However, the PDP 1 has a plurality of X electrodes 14 and Y electrodes 15 according to the number of display lines. Yes.
　このＸ電極１４およびＹ電極１５は一般に例えば、ＩＴＯ（Ｉｎｄｉｕｍ　Ｔｉｎ　Ｏｘｉｄｅ）やＳｎＯ２などの透明な電極材料で構成されるＸ透明電極１４ａ、Ｙ透明電極１５ａと、例えば、Ａｇ（銀）、Ａｕ（金）、Ａｌ（アルミニウム）、Ｃｕ（銅）、Ｃｒ（クロム）、あるいはこれらの積層体（例えばＣｒ／Ｃｕ／Ｃｒの積層体）などからなるＸバス電極（金属電極部）１４ｂ、Ｙバス電極（金属電極部）１５ｂとで構成される。 The X electrode 14 and the Y electrode 15 are generally composed of, for example, an X transparent electrode 14a and a Y transparent electrode 15a made of a transparent electrode material such as ITO (Indium Tin Oxide) or SnO 2, and, for example, Ag (silver), Au X bus electrode (metal electrode part) 14b made of (gold), Al (aluminum), Cu (copper), Cr (chromium), or a laminate thereof (for example, a laminate of Cr / Cu / Cr), Y bus It is comprised with the electrode (metal electrode part) 15b.
　図１では、Ｘ透明電極１４ａ、Ｙ透明電極１５ａが帯状に延びる形状を示しているが、Ｘ透明電極１４ａ、Ｙ透明電極１５ａの電極構造はこれに限定されない。例えば、維持放電の安定化や放電効率の向上のため、一対の電極対間の最短距離（放電ギャップと呼ばれる）がセルに対応して近づくようにＸバス電極１４ｂ、Ｙバス電極１５ｂと重なる位置からそれぞれ対向する方向に突出部を形成する構造としても良い。また、電極構造をいわゆるＡＬＩＳ（Alternate Lighting of Surface Method）と呼ばれる構造としても良い。 FIG. 1 shows the X transparent electrode 14a and the Y transparent electrode 15a extending in a strip shape, but the electrode structure of the X transparent electrode 14a and the Y transparent electrode 15a is not limited to this. For example, in order to stabilize sustain discharge and improve discharge efficiency, the position where the shortest distance between the pair of electrodes (referred to as a discharge gap) overlaps with the X bus electrode 14b and the Y bus electrode 15b so as to approach the cell. It is good also as a structure which forms a protrusion part in the direction which respectively opposes. The electrode structure may be a so-called ALIS (AlternateternLighting of Surface Method).
　これらの電極群（Ｘ電極１４、Ｙ電極１５）は、主にＳｉＯ２などのガラス材料で構成される誘電体層１７で被覆されている。この誘電体層１７は、前面基板１３の第２の面１３ｂ側に形成され、第２の面１３ａと対向する第３の面１７ａと、第３の面１７ａの反対側に位置する第４の面１７ｂとを有している。 These electrodes (X electrodes 14, Y electrodes 15) is mainly covered by the configured dielectric layers 17 of a glass material such as SiO 2. The dielectric layer 17 is formed on the second surface 13b side of the front substrate 13, and a third surface 17a facing the second surface 13a and a fourth surface positioned on the opposite side of the third surface 17a. And a surface 17b.
　また、誘電体層１７の表面には、ＭｇＯなどの金属酸化物で構成される保護膜１８が形成されている。保護膜１８は誘電体層１７の一方の表面を覆うように形成されている。 A protective film 18 made of a metal oxide such as MgO is formed on the surface of the dielectric layer 17. The protective film 18 is formed so as to cover one surface of the dielectric layer 17.
　一方、背面基板構造体１２は、主にガラスで構成される背面基板（基板）１９を有している。背面基板１９の前面基板構造体１１と対向する面（内側面）上には、複数のアドレス電極（第２電極）２０が形成されている。各アドレス電極２０は、Ｘ電極１４およびＹ電極１５が延在する方向と交差する（略直交する）列方向ＤＹに沿って延在するように形成されている。また、各アドレス電極２０は、互いに略平行となるように所定の配置間隔を持って配置されている。 On the other hand, the back substrate structure 12 has a back substrate (substrate) 19 mainly made of glass. A plurality of address electrodes (second electrodes) 20 are formed on the surface (inner surface) of the rear substrate 19 facing the front substrate structure 11. Each address electrode 20 is formed so as to extend along a column direction DY intersecting (substantially orthogonal to) the direction in which the X electrode 14 and the Y electrode 15 extend. The address electrodes 20 are arranged with a predetermined arrangement interval so as to be substantially parallel to each other.
　アドレス電極２０はＸバス電極１４ｂ、Ｙバス電極１５ｂと同様に、例えば、Ａｇ、Ａｕ、Ａｌ、Ｃｕ、Ｃｒ、あるいはこれらの積層体（例えばＣｒ／Ｃｕ／Ｃｒの積層体）などで構成することができる。 Similarly to the X bus electrode 14b and the Y bus electrode 15b, the address electrode 20 is made of, for example, Ag, Au, Al, Cu, Cr, or a laminate thereof (for example, a laminate of Cr / Cu / Cr). Can do.
　このアドレス電極２０と、前面基板構造体１１に形成されたＹ電極１５とは、セル２５の点灯／非点灯を選択するための放電であるアドレス放電を行うための電極対を構成する。つまり、Ｙ電極１５は維持放電用の電極としての機能とアドレス放電用の電極（走査電極）としての機能とを併せ持っている。 The address electrode 20 and the Y electrode 15 formed on the front substrate structure 11 constitute an electrode pair for performing address discharge, which is discharge for selecting lighting / non-lighting of the cell 25. That is, the Y electrode 15 has both a function as a sustain discharge electrode and a function as an address discharge electrode (scanning electrode).
　セル２５は、アドレス電極２０と一対のＸ電極１４とＹ電極１５との交差に対応して各１個ずつ構成される。つまり、セル２５は表示電極対（Ｘ電極１４とＹ電極１５の対）とアドレス電極２０の交差毎に形成される。各セル２５は、維持放電によりそれぞれ赤（Ｒ）、緑（Ｇ）、青（Ｂ）の可視光を発光し、このＲ、Ｇ、Ｂの各セル２５のセットにより画素（ピクセル）が構成される。 Each cell 25 is configured to correspond to the intersection of the address electrode 20 and the pair of X electrode 14 and Y electrode 15. That is, the cell 25 is formed at each intersection of the display electrode pair (a pair of the X electrode 14 and the Y electrode 15) and the address electrode 20. Each cell 25 emits red (R), green (G), and blue (B) visible light by sustain discharge, and a pixel (pixel) is configured by the set of each R, G, and B cell 25. The
　また、アドレス電極２０は、誘電体層２１で被覆されている。誘電体層２１上には背面基板構造体１２の厚さ方向に伸びる複数の隔壁２２が形成されている。隔壁２２はアドレス電極２０が延在する列方向ＤＹに沿ってライン状に延在するように形成されている。前面基板構造体１１と背面基板構造体１２とは、保護膜１８が形成された面と隔壁２２が形成された面とが対向した状態で固定されている。隔壁２２の平面上の位置は、隣り合うアドレス電極２０の間に配置されている。隔壁２２を隣り合うアドレス電極２０の間に配置することにより、各アドレス電極の位置に対応して誘電体層２１の表面を列方向ＤＹに区分けする放電空間２４が形成される。 The address electrode 20 is covered with a dielectric layer 21. A plurality of partition walls 22 extending in the thickness direction of the back substrate structure 12 are formed on the dielectric layer 21. The barrier ribs 22 are formed to extend in a line along the column direction DY in which the address electrodes 20 extend. The front substrate structure 11 and the rear substrate structure 12 are fixed in a state where the surface on which the protective film 18 is formed and the surface on which the partition wall 22 is formed face each other. A position on the plane of the partition wall 22 is disposed between the adjacent address electrodes 20. By disposing the barrier ribs 22 between the adjacent address electrodes 20, a discharge space 24 for dividing the surface of the dielectric layer 21 in the column direction DY corresponding to the position of each address electrode is formed.
　放電空間２４（詳しくは、アドレス電極２０上の誘電体層２１の上面、および隔壁２２の側面）には、真空紫外線により励起されてＲ、Ｇ、Ｂの各色の可視光を発生する蛍光体部２３ｒ、２３ｇ、２３ｂが形成されている。 In the discharge space 24 (specifically, the upper surface of the dielectric layer 21 on the address electrode 20 and the side surface of the barrier rib 22), a phosphor portion that is excited by vacuum ultraviolet rays and generates visible light of each color of R, G, and B. 23r, 23g, and 23b are formed.
　また、各放電空間２４には、放電ガスと呼ばれる希ガスなどのガスが所定の圧力で封入されている。放電ガスとしては、例えばＸｅの分圧比が数％～数十％に調整されたＸｅ－Ｎｅなどの混合ガスを用いて、封入されるガスの圧力は例えば３５０ｔｏｒｒ～５００ｔｏｒｒ（約４７ｋＰａ～約６７ｋＰａ）とすることができる。 Further, each discharge space 24 is filled with a gas such as a rare gas called a discharge gas at a predetermined pressure. As the discharge gas, for example, a mixed gas such as Xe-Ne whose Xe partial pressure ratio is adjusted to several to several tens of percent is used, and the pressure of the gas to be filled is 350 to 500 torr (about 47 to 67 kPa), for example. It can be.
　ＰＤＰ１は、放電空間２４内のセル２５毎に放電（維持放電）を発生させて、放電により発生する（詳しくは放電により励起状態となったイオンが基底状態に遷移する際に発生する）真空紫外線によりＲ、Ｇ、Ｂの各蛍光体部２３を励起して発光させる構造となっている。放電ガスとしてＮｅとＸｅの混合ガスを用いた場合、１４７ｎｍおよび１７２ｎｍの真空紫外線が各蛍光体部２３を励起する励起光として発生する。この真空紫外線（特にエキシマからの真空紫外線）の波長はある程度の幅を有している場合があるが、１４７ｎｍ～１８０ｎｍの範囲に収まる。 The PDP 1 generates a discharge (sustain discharge) for each cell 25 in the discharge space 24, and is generated by the discharge (specifically, generated when an ion excited by the discharge transitions to a ground state). Thus, the R, G, B phosphor portions 23 are excited to emit light. When a mixed gas of Ne and Xe is used as the discharge gas, vacuum ultraviolet rays of 147 nm and 172 nm are generated as excitation light for exciting the phosphor parts 23. The wavelength of this vacuum ultraviolet ray (particularly the vacuum ultraviolet ray from the excimer) may have a certain range, but falls within the range of 147 nm to 180 nm.
　なお、図１では隔壁２２を帯状に形成する例について示しているが、隔壁の配置はこれには限定されない。例えば列方向ＤＹに沿って延在する第１隔壁としての隔壁２２に加えて、行方向ＤＸに沿って延在する第２隔壁を配置して放電空間２４を格子状に区画する構造としても良い。この場合、放電空間２４は、隔壁２２と第２隔壁とによりセル２５毎にボックス状に区画されるので、このような隔壁の構造はボックス構造と呼ばれる。また、図１ではアドレス電極２０を背面基板構造体１２に形成する例について示したが、アドレス電極２０を前面基板構造体１１に形成することもできる。 Although FIG. 1 shows an example in which the partition wall 22 is formed in a strip shape, the arrangement of the partition wall is not limited to this. For example, in addition to the barrier ribs 22 as the first barrier ribs extending along the column direction DY, a second barrier rib extending along the row direction DX may be arranged to partition the discharge space 24 in a grid pattern. . In this case, since the discharge space 24 is partitioned into a box shape for each cell 25 by the barrier ribs 22 and the second barrier ribs, such a barrier rib structure is called a box structure. 1 shows an example in which the address electrode 20 is formed on the back substrate structure 12, the address electrode 20 can also be formed on the front substrate structure 11.
　＜明室コントラストについて＞
　次に、図２を用いてＰＤＰの明室コントラストについて説明する。図２はＰＤＰに入射される外光とＰＤＰからの表示光との関係を示す説明図である。なお、図２では外光と表示光との関係を判りやすくするため、ＰＤＰ１、２の構造は単純化したモデルで示している。 <About bright room contrast>
Next, the bright room contrast of the PDP will be described with reference to FIG. FIG. 2 is an explanatory diagram showing the relationship between external light incident on the PDP and display light from the PDP. In FIG. 2, the structure of the PDPs 1 and 2 is shown as a simplified model so that the relationship between the external light and the display light can be easily understood.
　図２において、ＰＤＰ１、２は表示光Ｐの発光輝度がＩｉ、反射率がＲｉの表示装置であり、その表示面（前面）側には透過率ＴｉのフィルタＦが配置されている。ここで、ＰＤＰ１の表示面側に輝度Ｉ０の外光Ｌを垂直入射したときの明室コントラストをＣｉとすると、Ｃｉは以下に示す式（１）で与えられる。 In FIG. 2, PDP1 and PDP2 are display devices whose display light P has emission luminance I i and reflectance R i , and a filter F having transmittance T i is disposed on the display surface (front surface) side. . Here, the bright room contrast when the external light L luminance I 0 was vertically incident on the display surface side of the PDP1 and C i, C i is given by Equation (1) below.
　Ｃｉ＝Ｉｉ／（Ｔｉ×Ｒｉ×Ｉ０）　・・・（１）
　上記式（１）が成立するためには、外光ＬがフィルタＦで反射される項が無視できる程度であることが必要となるが、これはフィルタＦの透過率Ｔｉが数十％であれば成立するので、一般的な表示装置では成立する。 C i = I i / (T i × R i × I 0 ) (1)
In order for the above formula (1) to hold, it is necessary that the term in which the external light L is reflected by the filter F is negligible. This is because the transmittance T i of the filter F is several tens of percent. Since it is established if there is, it is established in a general display device.
　ここで、２つのＰＤＰ１、２（ｉ＝１、２）がある場合に、このＰＤＰ１、２の明室コントラストが同じとすると、以下の式（２）が成立する。 Here, when there are two PDPs 1 and 2 (i = 1, 2), and the bright room contrast of the PDPs 1 and 2 is the same, the following equation (2) is established.
　Ｉ１／（Ｔ１×Ｒ１）＝Ｉ２／（Ｔ２×Ｒ２）　・・・（２）
　したがってＰＤＰ１、２の観察者から見たＰＤＰ１、２の輝度比（Ｔ１×Ｉ１）（Ｔ２×Ｉ２）に上記（２）式を代入すると以下の（３）式が得られる。 I 1 / (T 1 × R 1 ) = I 2 / (T 2 × R 2 ) (2)
Therefore, the following equation (3) is obtained by substituting the above equation (2) into the luminance ratio (T 1 × I 1 ) (T 2 × I 2 ) of the PDPs 1 and 2 viewed from the observer of the PDPs 1 and 2 .
　（Ｔ１×Ｉ１）／（Ｔ２×Ｉ２）＝（Ｉ１ ２×Ｒ１）／（Ｉ２ ２×Ｒ２）　・・・（３）
　したがって、同じ明室コントラストを得るという条件では、ＰＤＰ１の表示輝度（観察者から見た輝度）は反射率の逆数比例で有利になる。つまり、外光Ｌの輝度Ｉ０を一定とすると、明室コントラストＣｉは発光輝度Ｉｉを高くして、反射率Ｒｉを低くするほど改善することができる。 (T 1 × I 1 ) / (T 2 × I 2 ) = (I 1 2 × R 1 ) / (I 2 2 × R 2 ) (3)
Therefore, under the condition that the same bright room contrast is obtained, the display brightness of the PDP 1 (the brightness seen by the observer) is advantageous in the inverse proportion of the reflectance. That is, if the luminance I 0 of the external light L is constant, the bright room contrast C i can be improved as the light emission luminance I i is increased and the reflectance R i is decreased.
　ここで、図１に示すＰＤＰ１は前面基板構造体１１とその反対側に対向配置される背面基板構造体１２とを重ね合わせた構造となっている。ＰＤＰ１において、外光の反射率に対する影響が大きい部材は背面基板構造体１２の特に蛍光体部２３である。以下蛍光体部２３が形成される背面基板構造体１２の反射率の低減手段について説明する。 Here, the PDP 1 shown in FIG. 1 has a structure in which a front substrate structure 11 and a rear substrate structure 12 disposed opposite to each other are overlapped. In the PDP 1, a member having a large influence on the reflectance of external light is the phosphor portion 23 of the back substrate structure 12. Hereinafter, a means for reducing the reflectance of the back substrate structure 12 on which the phosphor portion 23 is formed will be described.
　図３は図１に示すＰＤＰが有する背面基板構造体の構造について反射率低減の効果を説明するために単純化したモデルとして示す説明図である。 FIG. 3 is an explanatory diagram showing a simplified model for explaining the effect of reducing the reflectivity of the structure of the back substrate structure of the PDP shown in FIG.
　図３において、背面構造体１２が有する背面基板１９の上には蛍光体部２３が形成されている。この蛍光体部２３はそれぞれ赤、緑、青の可視光を発光する蛍光体部２３ｒ、２３ｇ、２３ｂが区画されて配置されている。 In FIG. 3, a phosphor portion 23 is formed on the back substrate 19 included in the back structure 12. This phosphor portion 23 is arranged with phosphor portions 23r, 23g, and 23b that emit visible light of red, green, and blue, respectively.
　まず、蛍光体部２３が白色である場合について説明する。なお、ここでは説明を判りやすくするため、白色の蛍光体部２３、および背面基板１９は完全反射状態（反射率が１００％の状態）であると仮定する。 First, the case where the phosphor part 23 is white will be described. Here, for easy understanding, it is assumed that the white phosphor portion 23 and the back substrate 19 are in a completely reflective state (a state where the reflectance is 100%).
　蛍光体部２３および背面基板１９が完全反射状態である場合、背面基板構造体１２の反射率は１（１００％）となる。また、蛍光体部２３から発光される可視光の輝度をＩとすると、蛍光体部２３からの発光も全て反射されるため、背面基板構造体１２の発光輝度もＩとなる。 When the phosphor part 23 and the back substrate 19 are in a completely reflective state, the reflectivity of the back substrate structure 12 is 1 (100%). Further, assuming that the luminance of visible light emitted from the phosphor portion 23 is I, all the light emission from the phosphor portion 23 is also reflected, and thus the emission luminance of the rear substrate structure 12 is also I.
　次に、蛍光体部２３の色調が各蛍光体部２３ｒ、２３ｇ、２３ｂが発光する可視光と同系列の色調である場合を検討する。この場合、背面基板構造体１２の各蛍光体部２３ｒ、２３ｇ、２３ｂでの反射率を平均すると、平均反射率を１／３（約３３％）とすることができる。一方、背面基板構造体１２の発光輝度は、理想的には蛍光体部２３から発光される可視光が全て反射される状態となりＩとなる。 Next, the case where the color tone of the phosphor part 23 is the same color tone as the visible light emitted from each phosphor part 23r, 23g, 23b will be considered. In this case, when the reflectances at the phosphor portions 23r, 23g, and 23b of the back substrate structure 12 are averaged, the average reflectance can be reduced to 1/3 (about 33%). On the other hand, the emission luminance of the rear substrate structure 12 is ideally set to I because all visible light emitted from the phosphor portion 23 is reflected.
　したがって、明室コントラストを一定とした場合、蛍光体部２３の色調を各蛍光体部２３ｒ、２３ｇ、２３ｂが発光する可視光と同系列の色調とすることにより、背面基板構造体１２の表示輝度（観察者から見た輝度）を３倍（蛍光体部２３が白色である場合に対して）の高輝度とすることができる。 Accordingly, when the bright room contrast is constant, the display luminance of the back substrate structure 12 is obtained by setting the color tone of the phosphor portion 23 to the same color tone as the visible light emitted by the phosphor portions 23r, 23g, and 23b. (Luminance as viewed from the observer) can be made three times as high (as compared to the case where the phosphor portion 23 is white).
　図１に示すＰＤＰ１において、上記技術を適用する場合、赤、緑、青の各色調を有する無機顔料粒子と略白色の蛍光体粒子とを混合した混合物である蛍光体を蛍光体部２３として用いることとなる。 In the PDP 1 shown in FIG. 1, when the above technique is applied, a phosphor that is a mixture of inorganic pigment particles having red, green, and blue color tones and substantially white phosphor particles is used as the phosphor portion 23. It will be.
　ところが、蛍光体粒子と一般に顔料として用いられる無機顔料粒子とを単に混合したのみでは、上記した表示輝度を向上させる効果が得られない。 However, the effect of improving the display luminance cannot be obtained by simply mixing phosphor particles and inorganic pigment particles generally used as pigments.
　例えば、蛍光体粒子の表面が、無機顔料粒子で覆われている場合、無機顔料粒子が蛍光体粒子に照射される励起光を吸収してしまう。このため、ＰＤＰ１の励起源である真空紫外線のように物質への透過長が無機顔料粒子の平均粒子径と同程度以下の励起源である場合、無機顔料粒子による励起エネルギーの吸収が発生し、その分のロスが蛍光体部２３の発光輝度の低下を引き起こす原因の一つとなる。また、励起光が蛍光体粒子に届いても、蛍光体粒子から発光する可視光がその表面を覆った無機顔料粒子により吸収される。この結果、蛍光体部２３の発光輝度が低下する。 For example, when the surface of the phosphor particles is covered with inorganic pigment particles, the inorganic pigment particles absorb the excitation light irradiated on the phosphor particles. For this reason, when the penetration length to the substance is an excitation source that is equal to or less than the average particle diameter of the inorganic pigment particles, such as vacuum ultraviolet rays that are the excitation source of PDP1, absorption of excitation energy by the inorganic pigment particles occurs, This loss is one of the causes that cause a decrease in the light emission luminance of the phosphor portion 23. Further, even if the excitation light reaches the phosphor particles, visible light emitted from the phosphor particles is absorbed by the inorganic pigment particles covering the surface. As a result, the light emission luminance of the phosphor portion 23 is lowered.
　一方、無機顔料粒子の表面が蛍光体粒子で覆われている場合、発光輝度の低下は抑制することができる。しかし、無機顔料粒子の表面に形成された蛍光体粒子層の層厚が厚すぎると、蛍光体粒子層に照射された外光Ｌの散乱が発生し、この散乱に起因して反射率が上昇する。特に、蛍光体粒子の平均粒子径を１～５μｍとすると、この散乱に起因する反射成分だけで反射率は１０％以上上昇する。このため、蛍光体部２３の反射率を十分に低下させることができず、結果として、上記した表示輝度を向上させる効果が得られなくなる。 On the other hand, when the surface of the inorganic pigment particles is covered with the phosphor particles, it is possible to suppress a decrease in emission luminance. However, if the thickness of the phosphor particle layer formed on the surface of the inorganic pigment particle is too thick, scattering of the external light L irradiated to the phosphor particle layer occurs, and the reflectance increases due to this scattering. To do. In particular, when the average particle diameter of the phosphor particles is 1 to 5 μm, the reflectance increases by 10% or more with only the reflection component resulting from the scattering. For this reason, the reflectance of the phosphor portion 23 cannot be sufficiently reduced, and as a result, the above-described effect of improving the display luminance cannot be obtained.
　本発明者は、発光輝度あるいは表示輝度の低下を抑制しつつ、外光の反射率を低減させる技術について検討を行い、励起光のエネルギーよりも大きいバンドギャップと、バンドギャップ内に形成された不純物準位とを有する結晶母体を有し、不純物準位のＨＯＭＯ準位から、結晶母体の伝導帯までのエネルギー幅が励起光のエネルギーと異なる無機顔料粒子を蛍光体粒子と混合して蛍光体部２３を形成する構成を見出した。以下蛍光体部２３の具体的な構成について説明する。 The present inventor has studied a technique for reducing the reflectance of outside light while suppressing a decrease in light emission luminance or display luminance, and a band gap larger than the energy of excitation light and impurities formed in the band gap. And a phosphor part by mixing inorganic pigment particles having different energy widths from the HOMO level of the impurity level to the conduction band of the crystal matrix and the energy of the excitation light with the phosphor particles. The structure which forms 23 was found. Hereinafter, a specific configuration of the phosphor portion 23 will be described.
　＜蛍光体の詳細構成＞
　図４は本実施の形態の蛍光体部の詳細な構成を示す要部拡大断面図、図５は図４に示す蛍光体部を構成する無機顔料のエネルギーバンドを示すバンド図である。なお、図４に示す蛍光体部２３の構造は赤用の蛍光体部２３ｒ、緑用の蛍光体部２３ｇ、青用の蛍光体部２３ｂに共通する構造である。 <Detailed structure of phosphor>
FIG. 4 is an enlarged cross-sectional view of the main part showing the detailed configuration of the phosphor part of the present embodiment, and FIG. 5 is a band diagram showing the energy band of the inorganic pigment constituting the phosphor part shown in FIG. The structure of the phosphor portion 23 shown in FIG. 4 is a structure common to the phosphor portion 23r for red, the phosphor portion 23g for green, and the phosphor portion 23b for blue.
　図４において、蛍光体部２３は蛍光体粒子（蛍光体）３１と、この蛍光体粒子３１と混合される無機顔料粒子（無機顔料）３２とを有している。図４では、蛍光体粒子３１と無機顔料粒子３２との区別を判りやすく示すため、これらを円形の断面形状を有する粒子として示しているが、蛍光体粒子３１および無機顔料粒子３２の構造はこれに限定されない。例えば、蛍光体粒子３１および無機顔料粒子３２の断面形状が扁平した構造となっている場合もある。また、例えば、ＰＤＰ１（図１参照）の製造工程には種々の加熱工程があるが、この加熱工程によって、蛍光体粒子３１と無機顔料粒子３２の一部、蛍光体粒子３１同士、無機顔料粒子３２同士の一部が固着して一体化する場合がある。蛍光体部２３は蛍光体と無機顔料の混合物であれば良く、このように各粒子の一部が固着して一体化した構造であっても良い。 4, the phosphor portion 23 includes phosphor particles (phosphor) 31 and inorganic pigment particles (inorganic pigment) 32 mixed with the phosphor particles 31. In FIG. 4, in order to show the distinction between the phosphor particles 31 and the inorganic pigment particles 32, these are shown as particles having a circular cross-sectional shape, but the structures of the phosphor particles 31 and the inorganic pigment particles 32 are the same. It is not limited to. For example, the phosphor particles 31 and the inorganic pigment particles 32 may have a flat cross-sectional shape. Further, for example, there are various heating processes in the manufacturing process of the PDP 1 (see FIG. 1). By this heating process, a part of the phosphor particles 31 and the inorganic pigment particles 32, the phosphor particles 31 each other, the inorganic pigment particles In some cases, a part of 32 may be fixed and integrated. The phosphor part 23 may be a mixture of a phosphor and an inorganic pigment, and may have a structure in which a part of each particle is fixed and integrated.
　蛍光体粒子３１を構成する材料は、例えば、赤用の蛍光体粒子３１ｒには(Ｙ，Ｇｄ)２Ｏ３:Ｅｕ、緑用の蛍光体粒子３１ｇにはＺｎ２ＳｉＯ４:Ｍｎ、ＹＢＯ３:Ｔｂ、青用の蛍光体粒子３１ｂにはＢａＭｇＡｌ１０Ｏ１７:Ｅｕ２＋を例示することができる。この蛍光体粒子３１ｒ、３１ｇ、３１ｂは、励起源である励起光（本実施の形態では、波長が１４７ｎｍおよび１７２ｎｍの真空紫外線）に励起されることにより、それぞれ赤色、緑色、青色の光を発光する。 The material constituting the phosphor particles 31 is, for example, (Y, Gd) 2 O 3 : Eu for the phosphor particles 31r for red, and Zn 2 SiO 4 : Mn, YBO 3 for the phosphor particles 31g for green. BaMgAl 10 O 17 : Eu 2+ can be exemplified as the phosphor particles 31b for: Tb and blue. The phosphor particles 31r, 31g, and 31b emit red, green, and blue light, respectively, by being excited by excitation light that is an excitation source (in this embodiment, vacuum ultraviolet rays having wavelengths of 147 nm and 172 nm). To do.
　一方、無機顔料粒子３２は、例えば、赤色の無機顔料粒子３２ｒには、ルビー(Ａｌ２Ｏ３：Ｃｒ)、緑色の無機顔料粒子３１ｇにはグリーンサファイア（Ａｌ２Ｏ３：Ｆｅ）、青色の無機顔料粒子３２ｂにはブルーサファイア（Ａｌ２Ｏ３：Ｔｉ）を用いている。これらはいずれもコランダムと呼ばれる結晶体であり、結晶母体であるアルミナ（Ａｌ２Ｏ３）に不純物として３ｄ遷移金属であるＣｒ、Ｆｅ（鉄）、Ｔｉ（チタン）がそれぞれ導入されたものである。 On the other hand, the inorganic pigment particles 32 include, for example, ruby (Al 2 O 3 : Cr) for red inorganic pigment particles 32r, green sapphire (Al 2 O 3 : Fe) for blue inorganic pigment particles 31g, and blue Blue sapphire (Al 2 O 3 : Ti) is used for the inorganic pigment particles 32b. All of these are crystal bodies called corundum, in which 3d transition metals Cr, Fe (iron), and Ti (titanium) are introduced as impurities into alumina (Al 2 O 3 ), which is a crystal base. .
　無機顔料粒子３２の結晶母体であるアルミナは、図５に示すように伝導帯（Conduction band）ＣＢと価電子帯（valence band）ＶＢとの間に約１０ｅＶのバンドギャップＷ１を有している。一方、ＰＤＰ１の励起源である波長が１４７ｎｍ、１７２ｎｍの真空紫外線はそれぞれ約８．４ｅＶ、約７．２ｅＶとなっており、アルミナのバンドギャップＷ１は励起光のエネルギーよりも大きい。前述した蛍光体部２３を構成する無機顔料粒子による励起光の遮光は、無機顔料粒子に励起光のエネルギーが吸収される（価電子帯ＶＢの電子が励起光に励起されて伝導帯ＣＢに遷移する）ことにより発生する。本実施の形態で用いるアルミナは励起光のエネルギーよりも大きいバンドギャップＷ１を有するので、励起光が照射されても価電子帯ＶＢの電子が伝導体ＣＢに遷移せず、励起光の吸収率が低い。つまり、励起光である真空紫外線に対して透明である。このように真空紫外線に対する透過率が高い特性を有する材料としてスピネル（ＭｇＡｌ２Ｏ４）を用いることもできるが、アルミナはスピネルよりも励起光である１４７ｎｍ、１７２ｎｍの波長光（真空紫外光）に対する透過率が高いのでより好ましい。 As shown in FIG. 5, alumina, which is the crystal matrix of the inorganic pigment particles 32, has a band gap W1 of about 10 eV between the conduction band CB and the valence band VB. On the other hand, vacuum ultraviolet rays having wavelengths of 147 nm and 172 nm, which are excitation sources of PDP1, are about 8.4 eV and 7.2 eV, respectively, and the band gap W1 of alumina is larger than the energy of the excitation light. The above-described light shielding of the excitation light by the inorganic pigment particles constituting the phosphor portion 23 is such that the inorganic pigment particles absorb the energy of the excitation light (electrons in the valence band VB are excited by the excitation light and transition to the conduction band CB. Generated). Since alumina used in this embodiment has a band gap W1 larger than the energy of excitation light, electrons in the valence band VB do not transition to the conductor CB even when irradiated with excitation light, and the absorption rate of excitation light is high. Low. That is, it is transparent to vacuum ultraviolet rays that are excitation light. As described above, spinel (MgAl 2 O 4 ) can be used as a material having a high transmittance with respect to vacuum ultraviolet rays, but alumina is more sensitive to light having a wavelength of 147 nm and 172 nm (vacuum ultraviolet light) than excitation light. Since the transmittance is high, it is more preferable.
　また、蛍光体部２３の外光に対する反射率は、無機顔料粒子３２の可視光の吸収特性によって決定される。無機顔料３２の可視光吸収特性は以下のように決定される。アルミナに３ｄ遷移金属元素を導入すると、３ｄ遷移金属イオンがアルミナのＡｌ３＋イオンと置換される。例えば、３ｄ遷移元素としてＣｒを導入すると、Ｃｒ３＋イオンが一部のＡｌ３＋イオンと置換して、置換されたサイトでは、結晶母体であるアルミナのバンドギャップＷ１の間に図５に示すような不純物準位が形成される。Ｃｒ３＋イオンの３ｄ電子の軌道であって、５重に縮退していた３ｄ軌道はＣｒ３＋イオンの周囲の配位子場の影響により縮退が解けてエネルギーの低いｔ２ｇ軌道（３重縮退）と、エネルギーの高いｅｇ軌道（２重縮退）に***し、これが不純物準位となる。 Further, the reflectance of the phosphor portion 23 with respect to the external light is determined by the visible light absorption characteristics of the inorganic pigment particles 32. The visible light absorption characteristics of the inorganic pigment 32 are determined as follows. When a 3d transition metal element is introduced into alumina, the 3d transition metal ions are replaced with alumina Al 3+ ions. For example, when Cr is introduced as a 3d transition element, Cr 3+ ions are replaced with some Al 3+ ions, and at the substituted sites, as shown in FIG. 5 between the band gap W1 of alumina, which is the crystal matrix. Impurity levels are formed. 3d electron orbit of Cr 3+ ion, 3d orbital which was degenerate in 5fold is degenerated due to the influence of ligand field around Cr3 + ion, and t2g orbital with low energy (triple degeneracy) If, it split into high e g orbitals energy (double stuck), which is the impurity level.
　このエネルギーの低いｔ２ｇ軌道とエネルギーの高いｅｇ軌道とのエネルギー幅Ｗ２が無機顔料粒子３２の可視光吸収特性を決定する要因となる。例えば、ルビーの場合、エネルギー幅Ｗ２は約２．３ｅＶであり、ここに外光（簡単のため白色光とする）が照射されると、紫や黄緑の波長域の可視光がエネルギーの低いｔ２ｇ軌道につまっている電子の遷移エネルギーとして吸収される（この結果、ルビーは補色である赤色を呈する）。このため、無機顔料粒子３２により外光が吸収されるのでＰＤＰ１（図１参照）の反射率を低減することができる。 Energy width W2 of the lower t 2 g orbitals and high e g orbitals energy of this energy is a factor which determines the visible light absorption properties of the inorganic pigment particles 32. For example, in the case of ruby, the energy width W2 is about 2.3 eV, and when it is irradiated with external light (white light for simplicity), visible light in the wavelength range of purple and yellow-green has low energy. It is absorbed as the transition energy of electrons clogged in the t 2g orbital (as a result, ruby exhibits a complementary color, red). For this reason, since external light is absorbed by the inorganic pigment particles 32, the reflectance of the PDP 1 (see FIG. 1) can be reduced.
　アルミナに３ｄ遷移金属を導入すると、可視光領域に強い光吸収特性を有する不純物準位が形成されるので、不純物は上記したＣｒ、Ｆｅ、Ｔｉの他、Ｓｃ（スカンジウム）、Ｖ（バナジウム）、Ｍｎ（マンガン）、Ｃｏ（コバルト）、Ｎｉ（ニッケル）、Ｃｕ（銅）、Ｚｎ（亜鉛）などを導入することもできる。また、２種以上の３ｄ遷移金属を導入することもできる。例えば、青色の色調を呈するサファイアには、不純物としてＦｅおよびＴｉが導入されているものもある。また、不純物準位には、結晶母体であるアルミナ中に形成された欠陥準位も含まれるが、この欠陥準位が可視光吸収特性を有する場合、不純物を導入した場合と同様に外光を吸収することができる。 When a 3d transition metal is introduced into alumina, an impurity level having a strong light absorption characteristic in the visible light region is formed. Therefore, in addition to Cr, Fe, and Ti, the impurities are Sc (scandium), V (vanadium), Mn (manganese), Co (cobalt), Ni (nickel), Cu (copper), Zn (zinc), etc. can also be introduced. Two or more 3d transition metals can also be introduced. For example, some sapphires exhibiting a blue color tone have Fe and Ti introduced as impurities. In addition, the impurity level includes a defect level formed in alumina which is a crystal base. When this defect level has a visible light absorption characteristic, external light is emitted in the same manner as when impurities are introduced. Can be absorbed.
　ただし、前述したように、蛍光体粒子３１ｒ、３１ｇ、３１ｂが発光する色調と同系列の色調を有する無機顔料粒子３２ｒ、３２ｇ、３２ｂをそれぞれ蛍光体粒子３１ｒ、３１ｇ、３１ｂと混合した場合、蛍光体粒子３１が発光する可視光の吸収を抑制することができる。したがって、蛍光体部２３の発光輝度の低下を抑制することができる。したがって、赤、緑、青の色調を有する（蛍光体粒子３１の発光色の補色となる色調に可視光吸収特性を有する）Ｃｒ、Ｆｅ、あるいはＴｉのいずれか１種または２種以上の不純物を導入して不純物準位を形成するのが特に好ましい。 However, as described above, when the inorganic pigment particles 32r, 32g, and 32b having the same color tone as that of the phosphor particles 31r, 31g, and 31b are mixed with the phosphor particles 31r, 31g, and 31b, respectively, Absorption of visible light emitted from the body particles 31 can be suppressed. Accordingly, it is possible to suppress a decrease in the light emission luminance of the phosphor portion 23. Therefore, any one or two or more impurities of Cr, Fe, or Ti having red, green, and blue color tones (having visible light absorption characteristics in the color tone complementary to the emission color of the phosphor particles 31) are contained. It is particularly preferable to introduce impurity levels.
　ここで、アルミナに導入した不純物により形成される不純物準位は、可視光の吸収特性の他、励起光である真空紫外線の吸収特性にも影響を与える。詳しく説明すると、エネルギーの低いｔ２ｇ軌道のうち電子によって占拠されている最もエネルギーの高い軌道（ＨＯＭＯ；Highest Occupied Molecular Orbital）のエネルギー準位（以下ＨＯＭＯ準位と記す）から結晶母体であるアルミナの伝導帯ＣＢまでのエネルギー幅Ｗ３が励起光である真空紫外線のエネルギーと等しい場合、ＨＯＭＯ準位の軌道を占拠する電子は真空紫外線を励起エネルギーとして吸収し、アルミナの伝導帯ＣＢに遷移する。したがって、真空紫外線の吸収を防止するためには、エネルギー幅Ｗ３と真空紫外線のエネルギーとを異なるものとする必要がある。図５に示すルビーの場合、アルミナの価電子帯ＶＢからＨＯＭＯ準位までのエネルギー幅Ｗ４は約０．９ｅＶであり、エネルギー幅Ｗ３は９．１ｅＶとなる。このようにエネルギー幅Ｗ３が励起光のエネルギーよりも大きいので、不純物準位に起因する励起光の吸収も防止ないしは抑制することができる。 Here, the impurity level formed by the impurities introduced into the alumina affects not only the absorption characteristic of visible light but also the absorption characteristic of vacuum ultraviolet light that is excitation light. More specifically, from the energy level of the highest energy orbital (HOMO) occupied by electrons among the low energy t 2g orbitals (hereinafter referred to as the HOMO level), the crystal matrix of alumina. When the energy width W3 to the conduction band CB is equal to the energy of vacuum ultraviolet light as excitation light, electrons occupying the orbit of the HOMO level absorb the vacuum ultraviolet light as excitation energy and transition to the conduction band CB of alumina. Therefore, in order to prevent absorption of vacuum ultraviolet rays, the energy width W3 and the energy of vacuum ultraviolet rays need to be different. In the case of the ruby shown in FIG. 5, the energy width W4 from the valence band VB of alumina to the HOMO level is about 0.9 eV, and the energy width W3 is 9.1 eV. As described above, since the energy width W3 is larger than the energy of the excitation light, the absorption of the excitation light due to the impurity level can be prevented or suppressed.
　なお、実際の励起状態では、可視光の吸収により電子が励起されるので田辺・菅野ダイヤグラムで説明されるように複雑であるが、本発明者は、エネルギーの低いｔ２ｇ軌道のエネルギー準位のうち、最も高いエネルギー準位（ＨＯＭＯ準位）からアルミナの伝導帯ＣＢまでのエネルギー幅Ｗ３が真空紫外線のエネルギーと異なっていれば、励起光の吸収による発光輝度の低下は実効上無視できる程度まで防止することができることを確認した。 In the actual excited state, electrons are excited by the absorption of visible light, which is complicated as described in the Tanabe / Ogino diagram. However, the present inventor has the energy level of the t 2g orbit with low energy. Of these, if the energy width W3 from the highest energy level (HOMO level) to the conduction band CB of alumina is different from the energy of vacuum ultraviolet rays, the decrease in emission luminance due to absorption of excitation light is effectively negligible. It was confirmed that it can be prevented.
　また、図４で示した緑色の無機顔料粒子３１ｇであるグリーンサファイア（Ａｌ２Ｏ３：Ｆｅ）および青色の無機顔料粒子３２ｂあるブルーサファイア（Ａｌ２Ｏ３：Ｔｉ）についても、アルミナの価電子帯ＶＢからＨＯＭＯ準位までのエネルギー幅Ｗ４は１ｅＶより小さい。したがって、エネルギー幅Ｗ３は９ｅＶ以上と励起光のエネルギーよりも大きいので、不純物準位に起因する励起光の吸収も防止することができる。 Further, for the green sapphire (Al 2 O 3 : Fe) which is the green inorganic pigment particle 31g and the blue sapphire (Al 2 O 3 : Ti) which is the blue inorganic pigment particle 32b shown in FIG. The energy width W4 from the band VB to the HOMO level is smaller than 1 eV. Therefore, since the energy width W3 is 9 eV or more, which is larger than the energy of the excitation light, absorption of the excitation light due to the impurity level can also be prevented.
　このように、本実施の形態によれば、蛍光体粒子３１と混合する無機顔料粒子３２の結晶母体を、励起光のエネルギーよりも大きいバンドギャップＷ１を有するアルミナとすることにより、励起光の吸収を防止ないしは抑制することができる。また、バンドギャップＷ１内に不純物準位（可視光吸収特性を有する不純物準位）を形成することにより、蛍光体部に照射された外光を吸収して反射率を低減することができる。また、不純物準位のＨＯＭＯ準位から、結晶母体の伝導帯までのエネルギー幅Ｗ３を励起光のエネルギーと異なるものとすることにより、ＨＯＭＯ準位から伝導帯への電子の遷移を防止ないしは抑制することができる。したがって、不純物準位に起因する励起光の吸収を防止ないしは抑制することができる。 As described above, according to the present embodiment, the crystal matrix of the inorganic pigment particles 32 mixed with the phosphor particles 31 is alumina having a band gap W1 larger than the energy of the excitation light, thereby absorbing the excitation light. Can be prevented or suppressed. Further, by forming an impurity level (impurity level having visible light absorption characteristics) in the band gap W1, it is possible to absorb external light irradiated on the phosphor portion and reduce the reflectance. Further, by making the energy width W3 from the HOMO level of the impurity level to the conduction band of the crystal base different from the energy of the excitation light, the transition of electrons from the HOMO level to the conduction band is prevented or suppressed. be able to. Accordingly, absorption of excitation light due to the impurity level can be prevented or suppressed.
　＜蛍光体粒子と無機顔料粒子との粒子径の関係＞
　ところで、蛍光体粒子の粒子径は一般に１～１０μｍ程度である。これに対し、一般的な無機顔料粒子の粒子径はインクなど液体に混合しても分散させられるように１μｍ以下、典型的には５～５００ｎｍである。つまり、無機顔料粒子の粒子径は一般に蛍光体粒子の粒子径よりも小さい。 <Relationship of particle size between phosphor particles and inorganic pigment particles>
By the way, the particle diameter of the phosphor particles is generally about 1 to 10 μm. On the other hand, the particle diameter of general inorganic pigment particles is 1 μm or less, typically 5 to 500 nm so that they can be dispersed even when mixed in a liquid such as ink. That is, the particle diameter of the inorganic pigment particles is generally smaller than the particle diameter of the phosphor particles.
　例えば、前記特許文献１に記載される赤色顔料（堺化学工業株式会社製：「ＦＲＯ－３」）の粒子径は１００ｎｍ程度である。また、緑色顔料（日精化工業株式会社製：「ＴＭグリーン＃３３４０」）の比表面積は１００ｍ２／ｇであり、その粒子径は１０～２０ｎｍ程度である。また、青色顔料（旭日産業株式会社製：「アサヒスーパーブルーＣＲ」）の粒子径は２００ｎｍ程度である。 For example, the particle size of the red pigment described in Patent Document 1 (manufactured by Sakai Chemical Industry Co., Ltd .: “FRO-3”) is about 100 nm. The specific surface area of the green pigment (manufactured by Nissei Kagaku Kogyo Co., Ltd .: “TM Green # 3340”) is 100 m 2 / g, and the particle diameter is about 10 to 20 nm. The particle diameter of the blue pigment (Asahi Sangyo Co., Ltd .: “Asahi Super Blue CR”) is about 200 nm.
　しかし、本実施の形態では、図４に示すように、無機顔料粒子３２の粒子径（平均粒子径）は蛍光体粒子３１の粒子径（平均粒子径）よりも大きい。以下、無機顔料粒子３２の粒子径を蛍光体粒子３１の粒子径（平均粒子径）よりも大きくすることにより得られる効果について説明する。 However, in the present embodiment, as shown in FIG. 4, the particle diameter (average particle diameter) of the inorganic pigment particles 32 is larger than the particle diameter (average particle diameter) of the phosphor particles 31. Hereinafter, the effect obtained by making the particle diameter of the inorganic pigment particles 32 larger than the particle diameter (average particle diameter) of the phosphor particles 31 will be described.
　本実施の形態で無機顔料粒子３２の結晶母体として用いるアルミナは、バンドギャップＷ１（図５参照）が１０ｅＶと可視光域のエネルギーよりも大きい。したがって、アルミナ自体は、励起光だけでなく、可視光に対しても透明である。無機顔料粒子３２はバンドギャップＷ１内に例えば不純物を導入して不純物準位を形成することにより、可視光吸収特性を得るものである。 The alumina used as the crystal matrix of the inorganic pigment particles 32 in the present embodiment has a band gap W1 (see FIG. 5) of 10 eV, which is larger than the energy in the visible light region. Therefore, alumina itself is transparent not only for excitation light but also for visible light. The inorganic pigment particles 32 obtain visible light absorption characteristics by, for example, introducing impurities into the band gap W1 to form impurity levels.
　しかし、アルミナ中のＡｌ３＋イオンの全てを不純物イオンに置換できる訳ではなく、不純物を導入する割合には限界がある。したがって、本実施の形態で用いる無機顔料粒子３２は上記したような一般に用いられる無機顔料と比較して単位表面積当りの可視光吸収量が低くなる。 However, not all Al 3+ ions in alumina can be replaced with impurity ions, and the ratio of introducing impurities is limited. Accordingly, the inorganic pigment particles 32 used in the present embodiment have a lower amount of visible light absorption per unit surface area than the above-described generally used inorganic pigments.
　そこで、本実施の形態では、無機顔料粒子３２の粒子径（平均粒子径）を蛍光体粒子３１の粒子径（平均粒子径）よりも大きいものとした。これにより、図１に示す蛍光体部２３における無機顔料粒子３２が占める表面積率を大きくすることができるので、蛍光体部２３全体としては、十分に外光を吸収することができる。したがって、蛍光体部２３の反射率を低減することができる。 Therefore, in the present embodiment, the particle diameter (average particle diameter) of the inorganic pigment particles 32 is larger than the particle diameter (average particle diameter) of the phosphor particles 31. Thereby, since the surface area ratio which the inorganic pigment particle 32 occupies in the fluorescent substance part 23 shown in FIG. 1 can be enlarged, external light can fully be absorbed as the fluorescent substance part 23 whole. Therefore, the reflectance of the phosphor part 23 can be reduced.
　＜ＰＤＰの製造方法＞
　次に、本実施の形態のＰＤＰの製造方法について説明する。ＰＤＰ１の製造工程は大きく分けると図１に示す前面基板構造体１１および背面基板構造体１２を準備する工程と、この前面基板構造体１１と背面基板構造体１２とを放電空間２４を介して対向配置して組み立てる工程とがある。本実施の形態では、背面基板構造体１２に形成された放電空間２４に蛍光体部２３を形成する工程について詳細に説明する。 <Manufacturing method of PDP>
Next, a method for manufacturing the PDP according to the present embodiment will be described. The manufacturing process of the PDP 1 is roughly divided into a process of preparing the front substrate structure 11 and the rear substrate structure 12 shown in FIG. 1, and the front substrate structure 11 and the rear substrate structure 12 facing each other through the discharge space 24. And arranging and assembling. In the present embodiment, the step of forming the phosphor portion 23 in the discharge space 24 formed in the back substrate structure 12 will be described in detail.
　図６は本実施の形態のＰＤＰが有する蛍光体部２３の製造フローを示す説明図である。図１に示す蛍光体部２３は例えば以下のように形成される。 FIG. 6 is an explanatory diagram showing a manufacturing flow of the phosphor portion 23 included in the PDP of the present embodiment. The phosphor part 23 shown in FIG. 1 is formed as follows, for example.
　（ａ）まず、ステップＳ１に示す準備の工程で蛍光体粒子３１と、平均粒子径が蛍光体粒子３１の平均粒子径よりも大きい無機顔料粒子３２とをそれぞれ準備する。この工程では、無機顔料粒子３２のバンドギャップＷ１（図５参照）内には不純物準位が形成されている。 (A) First, phosphor particles 31 and inorganic pigment particles 32 having an average particle diameter larger than the average particle diameter of the phosphor particles 31 are prepared in the preparation step shown in step S1. In this step, impurity levels are formed in the band gap W1 (see FIG. 5) of the inorganic pigment particles 32.
　（ｂ）次にステップＳ２に示す混合の工程で無機顔料粒子３２と蛍光体粒子３１とを混合して、蛍光体混合物３３を得る。本工程では無機顔料粒子３２と蛍光体粒子３１とが分散するように混合する。したがって、各粒子を分散混合させることができれば、種々の混合方法を用いることができる。例えば、ミキサなどを用いて混合することができる。また、例えば、溶液中に蛍光体粒子３１と無機顔料粒子３２とを分散させて混合することができる。 (B) Next, the inorganic pigment particles 32 and the phosphor particles 31 are mixed in the mixing step shown in step S2 to obtain a phosphor mixture 33. In this step, the inorganic pigment particles 32 and the phosphor particles 31 are mixed so that they are dispersed. Therefore, various mixing methods can be used as long as each particle can be dispersed and mixed. For example, mixing can be performed using a mixer or the like. Further, for example, the phosphor particles 31 and the inorganic pigment particles 32 can be dispersed and mixed in the solution.
　また、本工程では、最終的に形成される蛍光体部２３における無機顔料粒子３２の表面積率を制御するため、この被覆の工程では、添加する無機顔料粒子３２、および蛍光体粒子３１の表面積の総和を測定して添加量を決定することが好ましい。混合する段階で各粒子の表面積の総和を管理することにより、蛍光体部２３における無機顔料粒子３２の表面積率を容易に制御することができる。この結果、蛍光体部２３の外光に対する反射率を制御することができる。 Further, in this step, in order to control the surface area ratio of the inorganic pigment particles 32 in the phosphor portion 23 to be finally formed, in this coating step, the surface areas of the inorganic pigment particles 32 and the phosphor particles 31 to be added are determined. It is preferable to determine the addition amount by measuring the sum. By managing the total surface area of each particle at the stage of mixing, the surface area ratio of the inorganic pigment particles 32 in the phosphor portion 23 can be easily controlled. As a result, the reflectance with respect to the external light of the phosphor part 23 can be controlled.
　また、蛍光体部２３ｒ、２３ｇ、２３ｂ（図１参照）それぞれに異なる無機顔料粒子３２ｒ、３２ｇ、３２ｂ（図４参照）を含有させる場合には、赤用の蛍光体粒子３１ｒと赤色の無機顔料粒子３２ｒを、緑用の蛍光体粒子３１ｇと緑色の無機顔料粒子３２ｇを、青用の蛍光体粒子３１ｂと青色の無機顔料粒子３２ｂをそれぞれ別個に混合する。 When the phosphor parts 23r, 23g, and 23b (see FIG. 1) include different inorganic pigment particles 32r, 32g, and 32b (see FIG. 4), the red phosphor particles 31r and the red inorganic pigment are used. Particles 32r, green phosphor particles 31g and green inorganic pigment particles 32g, and blue phosphor particles 31b and blue inorganic pigment particles 32b are mixed separately.
　（ｃ）次に、ステップＳ３に示すペースト化の工程で有機溶剤、および有機バインダ剤などで構成されるビヒクル中に蛍光体混合物３３を混合して蛍光体ペースト３４を得る。 (C) Next, a phosphor paste 34 is obtained by mixing the phosphor mixture 33 in a vehicle composed of an organic solvent, an organic binder agent, and the like in the pasting step shown in step S3.
　このペースト化工程では、蛍光体混合物３３が蛍光体ペースト３４中に分散されていれば良く、混合方法は特に限定されない。 In this pasting step, the phosphor mixture 33 may be dispersed in the phosphor paste 34, and the mixing method is not particularly limited.
　（ｄ）次にステップＳ４に示す蛍光体ペースト塗布の工程で、蛍光体ペースト３４を図１に示す蛍光体部２３が形成される領域に蛍光体ペースト３４を塗布する。詳しくは、予め図３に示す背面基板１９の表面に複数のアドレス電極２０を形成し、次に、アドレス電極２０を覆うように誘電体層２１を形成し、次に、誘電体層２１の表面に複数の放電空間２４を規定する隔壁２２を形成しておく。ステップＳ４では、この隔壁２２で仕切られた放電空間２４（底面および側壁）に蛍光体ペースト３４を、例えばスクリーン印刷法やディスペンス法により塗布する。 (D) Next, in the phosphor paste application step shown in step S4, the phosphor paste 34 is applied to the region where the phosphor part 23 shown in FIG. 1 is formed. Specifically, a plurality of address electrodes 20 are formed in advance on the surface of the back substrate 19 shown in FIG. 3, then a dielectric layer 21 is formed so as to cover the address electrodes 20, and then the surface of the dielectric layer 21 is formed. The barrier ribs 22 that define the plurality of discharge spaces 24 are formed. In step S4, the phosphor paste 34 is applied to the discharge space 24 (bottom surface and side wall) partitioned by the barrier ribs 22 by, for example, a screen printing method or a dispensing method.
　なお、図１に示す蛍光体部２３ｒ、２３ｇ、２３ｂを形成するため、それぞれ赤、緑、青用の蛍光体ペースト３４を塗り分けることは言うまでもない。 Needless to say, in order to form the phosphor portions 23r, 23g, and 23b shown in FIG. 1, the phosphor pastes 34 for red, green, and blue are separately applied.
　（ｅ）次にステップＳ５に示す乾燥、焼成の工程で蛍光体ペースト３４中に含まれる有機化合物成分（有機溶剤および有機バインダ剤）を取り除き、蛍光体部２３が得られる。 (E) Next, the organic compound components (organic solvent and organic binder agent) contained in the phosphor paste 34 are removed in the drying and firing steps shown in step S5, and the phosphor portion 23 is obtained.
　このようにして得られた蛍光体部２３は、無機顔料粒子３２、蛍光体粒子３１の各１次粒子が分散された状態で形成されるため、ステップＳ２に示す混合の工程で設定したときの表面積率が反映される。 The phosphor part 23 obtained in this way is formed in a state where the primary particles of the inorganic pigment particles 32 and the phosphor particles 31 are dispersed, and therefore when set in the mixing step shown in step S2. The surface area ratio is reflected.
　また、本工程では、蛍光体ペースト３４を加熱するため、前述したように蛍光体粒子３１と無機顔料粒子３２の一部、蛍光体粒子３１同士、無機顔料粒子３２同士の一部が固着して一体化する。 Further, in this step, since the phosphor paste 34 is heated, as described above, a part of the phosphor particles 31 and the inorganic pigment particles 32, a part of the phosphor particles 31 and a part of the inorganic pigment particles 32 are fixed. Integrate.
　このように本実施の形態では、ステップＳ２に示す蛍光体粒子３１と無機顔料粒子３２とを混合する工程で、蛍光体粒子３１および無機顔料粒子３２の表面積を測定し、各粒子の添加量を決定することにより、蛍光体部２３の外光に対する反射率を安定的に低減することができる。 As described above, in the present embodiment, in the step of mixing phosphor particles 31 and inorganic pigment particles 32 shown in step S2, the surface areas of phosphor particles 31 and inorganic pigment particles 32 are measured, and the amount of each particle added is determined. By determining, the reflectance with respect to the external light of the fluorescent substance part 23 can be reduced stably.
　以上、本発明者によってなされた発明を実施の形態に基づき具体的に説明したが、本発明は前記発明の実施の形態に限定されるものではなく、その要旨を逸脱しない範囲で種々変更可能である。 As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment of the invention, and various modifications can be made without departing from the scope of the invention. is there.
　例えば、表示装置の適用例としてＰＤＰについて説明したが、光で蛍光体を励起して画像を表示する表示装置であれば、広く適用することができる。 For example, although the PDP has been described as an application example of the display device, the display device can be widely applied to any display device that displays an image by exciting a phosphor with light.
　本発明は、ＰＤＰなど、光で蛍光体を励起して画像を表示する表示装置に適用できる。 The present invention can be applied to a display device such as a PDP that displays an image by exciting a phosphor with light.

Claims (14)

  1. 　励起光で励起されることにより発光する蛍光体粒子と、前記蛍光体粒子と混合される無機顔料粒子とを有する蛍光体混合物であって、
    　前記無機顔料粒子は、前記励起光のエネルギーよりも大きいバンドギャップと、前記バンドギャップ内に形成された不純物準位とを有する結晶母体を有し、
    　前記不純物準位のＨＯＭＯ準位から、前記結晶母体の伝導帯までのエネルギー幅が前記励起光のエネルギーと異なることを特徴とする蛍光体混合物。     A phosphor mixture having phosphor particles that emit light when excited with excitation light, and inorganic pigment particles mixed with the phosphor particles,
    The inorganic pigment particles have a crystal matrix having a band gap larger than the energy of the excitation light and an impurity level formed in the band gap;
    A phosphor mixture, wherein an energy width from a HOMO level of the impurity level to a conduction band of the crystal base is different from an energy of the excitation light.
  2. 　請求項１に記載の蛍光体混合物において、
    　前記励起光の波長が１４７ｎｍ～１８０ｎｍの真空紫外線であることを特徴とする蛍光体混合物。     The phosphor mixture according to claim 1,
    A phosphor mixture, characterized in that the wavelength of the excitation light is vacuum ultraviolet light having a wavelength of 147 nm to 180 nm.
  3. 　請求項２に記載の蛍光体混合物において、
    　前記結晶母体はアルミナであって、前記不純物準位は、前記結晶母体内に導入された不純物により形成されることを特徴とする蛍光体混合物。     The phosphor mixture according to claim 2,
    The phosphor mixture, wherein the crystal matrix is alumina, and the impurity level is formed by impurities introduced into the crystal matrix.
  4. 　請求項３に記載の蛍光体混合物において、
    　前記不純物は、前記結晶母体のアルミニウムと置換されていることを特徴とする蛍光体混合物。     The phosphor mixture according to claim 3,
    The phosphor mixture, wherein the impurity is substituted with aluminum of the crystal matrix.
  5. 　請求項３に記載の蛍光体混合物において、
    　前記不純物は３ｄ遷移金属であることを特徴とする蛍光体混合物。     The phosphor mixture according to claim 3,
    The phosphor mixture, wherein the impurity is a 3d transition metal.
  6. 　請求項３に記載の蛍光体混合物において、
    　前記不純物はＣｒ（クロム）、Ｆｅ（鉄）、あるいはＴｉ（チタン）のいずれか１種または２種以上の物質であることを特徴とする蛍光体混合物。     The phosphor mixture according to claim 3,
    The phosphor mixture is characterized in that the impurity is one or more of Cr (chromium), Fe (iron), and Ti (titanium).
  7. 　請求項１に記載の蛍光体混合物において、
    　前記無機顔料粒子の粒子径は前記蛍光体粒子の粒子径よりも大きいことを特徴とする蛍光体混合物。     The phosphor mixture according to claim 1,
    The phosphor mixture, wherein the inorganic pigment particles have a particle size larger than that of the phosphor particles.
  8. 　基板と、
    　前記基板の一方の面側を複数の放電空間に区画する隔壁と、
    　前記複数の放電空間の各々に形成される蛍光体部とを有し、
    　前記蛍光体部は、
    　励起光で励起されることにより発光する蛍光体と、前記蛍光体と混合される無機顔料とを有し、
    　前記無機顔料は、前記励起光のエネルギーよりも大きいバンドギャップと、前記バンドギャップ内に形成された不純物準位とを有する結晶母体を有し、
    　前記不純物準位のＨＯＭＯ準位から、前記結晶母体の伝導帯までのエネルギー幅が前記励起光のエネルギーと異なることを特徴とするプラズマディスプレイパネル。     A substrate,
    Partition walls that divide one surface side of the substrate into a plurality of discharge spaces;
    A phosphor portion formed in each of the plurality of discharge spaces,
    The phosphor portion is
    A phosphor that emits light when excited by excitation light, and an inorganic pigment mixed with the phosphor,
    The inorganic pigment has a crystal matrix having a band gap larger than the energy of the excitation light and an impurity level formed in the band gap;
    A plasma display panel, wherein an energy width from a HOMO level of the impurity level to a conduction band of the crystal base is different from an energy of the excitation light.
  9. 　請求項８に記載のプラズマディスプレイパネルにおいて、
    　前記励起光の波長が１４７ｎｍ～１８０ｎｍの真空紫外線であることを特徴とするプラズマディスプレイパネル。     The plasma display panel according to claim 8, wherein
    A plasma display panel characterized in that the wavelength of the excitation light is vacuum ultraviolet light having a wavelength of 147 nm to 180 nm.
  10. 　請求項９に記載のプラズマディスプレイパネルにおいて、
    　前記結晶母体はアルミナであって、前記不純物準位は、前記結晶母体内に導入された不純物により形成されることを特徴とするプラズマディスプレイパネル。     The plasma display panel according to claim 9, wherein
    The plasma display panel according to claim 1, wherein the crystal matrix is alumina, and the impurity level is formed by impurities introduced into the crystal matrix.
  11. 　請求項１０に記載のプラズマディスプレイパネルにおいて、
    　前記不純物は、前記結晶母体のアルミニウムと置換されていることを特徴とするプラズマディスプレイパネル。     The plasma display panel according to claim 10, wherein
    The plasma display panel, wherein the impurities are substituted with aluminum of the crystal base.
  12. 　請求項１０に記載のプラズマディスプレイパネルにおいて、
    　前記不純物は３ｄ遷移金属であることを特徴とするプラズマディスプレイパネル。     The plasma display panel according to claim 10, wherein
    The plasma display panel, wherein the impurity is a 3d transition metal.
  13. 　請求項１０に記載のプラズマディスプレイパネルにおいて、
    　前記不純物はＣｒ（クロム）、Ｆｅ（鉄）、あるいはＴｉ（チタン）のいずれか１種または２種以上の物質であることを特徴とするプラズマディスプレイパネル。     The plasma display panel according to claim 10, wherein
    The plasma display panel according to claim 1, wherein the impurity is one or more of Cr (chromium), Fe (iron), and Ti (titanium).
  14. 　請求項８に記載のプラズマディスプレイパネルにおいて、
    　前記蛍光体部は、前記蛍光体の粒子である蛍光体粒子と、前記無機顔料の粒子である無機顔料粒子との混合物で形成され、前記無機顔料粒子の粒子径は前記蛍光体粒子の粒子径よりも大きいことを特徴とするプラズマディスプレイパネル。     The plasma display panel according to claim 8, wherein
    The phosphor portion is formed of a mixture of phosphor particles that are particles of the phosphor and inorganic pigment particles that are particles of the inorganic pigment, and the particle size of the inorganic pigment particles is the particle size of the phosphor particles. A plasma display panel characterized by being larger than.
PCT/JP2008/055446 2008-03-24 2008-03-24 Phosphor mixture and plasma display panel using the phosphor mixture WO2009118806A1 (en)

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