JP2013014679A - Display device, and rare earth phosphovanadate fluorescent substance used for the display device - Google Patents

Abstract

An object of the present invention is to provide a Eu ³⁺ -activated rare earth ^{phosphovanadate} phosphor that achieves both high luminance and short persistence and is stable and does not easily cause luminance saturation.
A display device using a rare earth phosphovanadate phosphor activated by Eu ³⁺ , wherein the rare earth phosphovanadate phosphor is fluorescent when excited with vacuum ultraviolet light having a wavelength of 146 nm. In the red light component emitted by the body, the peak height of the sub-light-emitting component near 614 nm with respect to the peak height of the main light-emitting component near 619 nm is defined as the first sub-light-emitting component ratio, and the peak height of the main light-emitting component is When the peak height of the auxiliary light emitting component near 697 nm is defined as the second auxiliary light emitting component ratio, the first auxiliary light emitting component ratio and the second auxiliary light emitting component ratio are 35.0% or more and 41.5%. It is characterized by being less than.
[Selection] Figure 16

Description

  The present invention relates to a display device such as a plasma display panel (PDP), a fluorescent lamp, and a field emission display (FED).

Conventionally, as a phosphor material used for a display device, a host crystal is Ln (P, V) O ₄ (where Ln is at least one selected from Sc, Y, La, Gd, and Lu). And a rare earth phosphovanadate phosphor (Eu ³⁺ activated rare earth phosphovanadate phosphor) containing at least Eu ³⁺ ions as an activator is known.

A typical example is Y (P, V) O ₄ : Eu ³⁺ red phosphor (hereinafter referred to as YPV), which has been practically used or studied for use in fluorescent lamps and plasma display panels (PDP). (For example, refer to Patent Documents 1 to 5 and Non-Patent Document 1).

It is known that the Eu ³⁺ activated rare earth ^{phosphovanadate} phosphor changes its emission spectrum shape and emission intensity by changing the ratio of phosphorus and vanadium. A composition with a small proportion of phosphorus can produce red light that is excellent in terms of red purity, but the emission intensity under vacuum ultraviolet (VUV) excitation decreases and the proportion of phosphorus (the number of phosphorus atoms relative to the total number of phosphorus and vanadium atoms is reduced). It is known that a composition having a phosphorous ratio of about 65 atomic% has a maximum emission intensity under VUV excitation, although it is slightly inferior in terms of red purity of red light (for example, , Patent Document 2, Non-Patent Document 1).

Note that Eu ³⁺ activated rare earth ^{phosphovanadate} phosphors that have been practically used for electronic devices have been manufactured by a general solid phase reaction, and alkali metal compounds and boron compounds are used as reaction accelerators. Is produced by reacting the phosphor raw material to which the above is added at a firing temperature of 1050 to 1250 ° C. (see, for example, Patent Documents 2, 3, and 5, Non-Patent Document 1).

Other than solid-phase reactions, for example, Eu ³⁺ activated rare earth phosphors produced by a spray pyrolysis method in which droplets of a solution (raw material solution) containing the constituent elements of the phosphor are heated to perform pyrolysis synthesis. Vanadate phosphors are known. A phosphor produced by a solid phase reaction is generally composed of a powder in which irregularly shaped particles are aggregated, whereas a phosphor produced by a spray pyrolysis method has a substantially spherical outer shape. It is known to become particles. In the spray pyrolysis method, the raw material solution is heated instantaneously (for example, 1 to 10 minutes as a reaction time) at a temperature of 1500 to 1700 ° C. (see, for example, Patent Document 4).

In the conventional light emitting device, the Eu ³⁺ activated rare earth ^{phosphovanadate} phosphor manufactured by such a manufacturing method has been used as the red phosphor. Such a rare earth phosphor having a composition having a short afterglow, such as a PDP with a stereoscopic image display function (hereinafter referred to as 3D-PDP), which requires a phosphor having a short afterglow, is used. Fovanadate phosphors have been used or discussed for use.

U.S. Pat. No. 3,417,027 Japanese Patent Publication No.57-352 Japanese Patent No. 3988337 JP 2004-256663 A JP 2009-256529 A

Phosphor Handbook, Ohm, pp. 233-235, pp. 332-333

However, conventional Eu ³⁺ activated rare earth ^{phosphovanadate} phosphors do not have both strong light emission and short persistence, particularly under VUV excitation, and contribute to lowering the luminance level of 3D-PDP. It was.

In order to obtain PDP red light having a relatively short persistence, it is effective to increase the vanadium ratio in the Eu ³⁺ activated rare earth phosphovanadate phosphor, but the VUV excitation increases as the vanadium ratio increases. Efficiency is reduced. In addition, since vanadium is unstable in terms of valence of ions, there is a problem that a phosphor having a higher vanadium ratio becomes more prominent in the PDP manufacturing process and phosphor deterioration due to PDP driving.

Furthermore, the conventional Eu ³⁺ activated rare earth ^{phosphovanadate} phosphor has a problem in that the luminance is saturated under strong VUV excitation.

On the other hand, the inventors have reported that the conventional Eu ^{3 +} -activated rare earth phosphovanadate phosphor crystals are incomplete, and even a practical phosphor that can be regarded as having a high degree of perfection has an atmosphere of about 1500 ° C. It was found that the light emission characteristics changed by heat treatment for several hours.

The present invention has been made to solve such problems, and provides an Eu ³⁺ -activated rare earth ^{phosphovanadate} phosphor that achieves both high luminance and short afterglow and is stable and hardly causes luminance saturation. The purpose is to provide.

In order to solve the above-mentioned problems, the present invention provides a display device using a rare earth phosphovanadate phosphor activated with Eu ³⁺ , wherein the rare earth phosphovanadate phosphor is a vacuum having a wavelength of 146 nm. In the red light component emitted by the phosphor when excited by ultraviolet rays, the peak height of the sub-light-emitting component near 614 nm to the peak height of the main light-emitting component near 619 nm is defined as the first sub-light-emitting component ratio. When the peak height of the auxiliary light emitting component near 697 nm with respect to the peak height of the light emitting component is defined as the second auxiliary light emitting component ratio, the first auxiliary light emitting component ratio and the second auxiliary light emitting component ratio are 35. It is 0% or more and less than 41.5%.

The present invention also relates to a rare earth phosphovanadate phosphor activated with Eu ³⁺ , which is a main component of around 619 nm in the red light component emitted by the phosphor when excited with vacuum ultraviolet light having a wavelength of 146 nm. The peak height of the sub-light-emitting component near 614 nm with respect to the peak height of the light-emitting component is defined as the first sub-light-emitting component ratio, and the peak height of the sub-light-emitting component near 697 nm with respect to the peak height of the main light-emitting component is the second. When the sub-light-emitting component ratio is set, the first sub-light-emitting component ratio and the second sub-light-emitting component ratio are 35.0% or more and less than 41.5%.

According to the present invention, it is possible to provide an Eu ³⁺ activated rare earth ^{phosphovanadate} phosphor that achieves both high luminance and short afterglow and is stable and hardly causes luminance saturation. Further, a display device using the Eu ³⁺ activated rare earth ^{phosphovanadate} phosphor, particularly a stereoscopic image display device, can be provided with an excellent display quality.

Sectional perspective view which shows the structure of PDP which comprises the plasma display apparatus in this invention. The figure which shows the drive circuit structure of the plasma display apparatus using PDP Sectional view showing the structure of the PDP A perspective view showing an example of a stereoscopic image display device using a plasma display device The figure which shows an example of the measurement data which calculates | requires 1/10 afterglow time of fluorescent substance powder Figure showing the relationship between the phosphor ratio of red phosphor, relative luminance value, and total photon number relative value Diagram showing emission spectra of red phosphors with different phosphorus ratios Diagram showing afterglow characteristics of red phosphors with different phosphorus ratios Diagram showing the luminance saturation phenomenon of red phosphors with different phosphorus ratios Diagram showing afterglow characteristics of red phosphor Reference diagram showing afterglow characteristics of red phosphor The figure which shows the main peak in the XRD pattern of red fluorescent substance Diagram showing emission spectrum of red phosphor Diagram showing afterglow characteristics of red phosphor Diagram showing luminance saturation phenomenon of red phosphor The figure which shows an example of the emission spectrum of red phosphor Diagram showing the relationship between emission peak height and phosphorus ratio

  Hereinafter, a display device according to an embodiment of the present invention and a rare earth phosphovanadate phosphor used in the display device will be described. The present invention can be used for a display device using a light emitting device such as a plasma display panel, a field emission display, a fluorescent lamp, and an LED. As an example of the display device, a plasma display panel will be described below as an example.

  FIG. 1 is a cross-sectional perspective view showing a configuration of a PDP constituting a plasma display device in the present invention. The PDP 10 includes a front plate 20 and a back plate 30. The front plate 20 has a front glass substrate 21, and a plurality of display electrode pairs 24 including scan electrodes 22 and sustain electrodes 23 arranged in parallel are formed on the front glass substrate 21. A dielectric layer 25 is formed so as to cover the scan electrode 22 and the sustain electrode 23, and a protective layer 26 is formed on the dielectric layer 25.

  On the other hand, the back plate 30 has a back glass substrate 31, and a plurality of address electrodes 32 arranged in parallel are formed on the back glass substrate 31. Further, a base dielectric layer 33 is formed so as to cover the address electrodes 32, and a partition wall 34 is formed thereon. Then, on the side surface of the partition wall 34 and the underlying dielectric layer 33, a red phosphor layer 35R, a green phosphor layer 35G, and a blue phosphor that sequentially emit light in red, green, and blue colors corresponding to the address electrodes 32, respectively. Layer 35B is provided.

  The front plate 20 and the back plate 30 are arranged to face each other so that the display electrode pair 24 and the address electrode 32 intersect each other with a minute discharge space interposed therebetween, and the outer peripheral portion thereof is sealed by a sealing member such as a glass frit. It is worn. In the discharge space, a mixed gas such as neon (Ne) and xenon (Xe) is sealed as a discharge gas at a pressure of 55 kPa to 80 kPa.

  The discharge space is partitioned into a plurality of sections by barrier ribs 34, and discharge cells 36 are formed at portions where the display electrode pairs 24 and the address electrodes 32 intersect. When a discharge voltage is applied between the electrodes, discharge occurs in the discharge cells 36, and the red phosphor layer 35R, the green phosphor layer 35G, and the blue phosphor layer 35B are caused by ultraviolet rays generated by the discharge. The phosphors are excited to emit light and a color image is displayed. Note that the structure of the PDP 10 is not limited to that described above. The structure of the partition wall 34 may be a structure provided with a cross-shaped partition wall.

  In the present invention, the red phosphor layer 35R includes at least a rare earth phosphovanadate phosphor, and preferably, all of the phosphors included in the red phosphor layer 35R include the rare earth phosphovanadate phosphor. Make your body.

Examples of the red phosphor other than the rare earth phosphovanadate phosphor included in the red phosphor layer 35R include Y ₂ O ₃ : Eu ³⁺ and (Y, Gd) ₂ O ₃ : Eu ^3+. Eu ³⁺ activated phosphors such as (Y, Gd) Al ₃ (BO ₃ ) ₄ : Eu ³⁺ .

Examples of the green phosphor included in the green phosphor layer 35G include Zn ₂ SiO ₄ : Mn ²⁺ , BaMgAl ₁₀ O ₁₇ : Mn ²⁺ , YBO ₃ : Tb ³⁺ , (Y, Gd) Al ₃ (BO ₃ ) ₄ : Tb ³⁺ , Y ₃ Al ₅ O ₁₂ : Ce ³⁺ , Y ₃ (Al, Ga) ₅ O ₁₂ : Ce ³⁺ , Ba ₃ Si ₆ O ₁₂ N ₂ : Eu ²⁺ , Mn ² Examples include at least one phosphor selected from a ⁺ activated phosphor, a Tb ³⁺ activated phosphor, a Ce ³⁺ activated phosphor, and an Eu ²⁺ activated phosphor.

In addition, a green phosphor having both the color tone of green light and short persistence is required for 3D. From this viewpoint, preferred green phosphors are Mn ²⁺ activated phosphor and Ce ³⁺ activated phosphor or A mixed green phosphor with Eu ²⁺ activated phosphor, for example, Zn ₂ SiO ₄ : Mn ²⁺ and Y ₃ Al ₅ O ₁₂ : Ce ³⁺ or Y ₃ (Al, Ga) ₅ O ₁₂ : Ce It is a mixed green phosphor formed by combining any of ³⁺ phosphors.

Examples of the blue phosphor included in the blue phosphor layer 35B include Eu ²⁺ activated phosphors such as BaMnAl ₁₀ O ₁₇ : Eu ²⁺ and CaMgSi ₂ O ₆ : Eu ²⁺ .

  FIG. 2 is a diagram showing a configuration of a plasma display device using the PDP 10. The plasma display device includes a PDP 10 and a drive circuit 40 connected to the PDP 10. The drive circuit 40 includes a display driver circuit 41, a display scan driver circuit 42, and an address driver circuit 43, and is connected to the sustain electrode 23, the scan electrode 22, and the address electrode 32 of the PDP 10, respectively. The controller 44 controls drive voltages applied to these various electrodes.

  Next, the discharge operation in the PDP 10 will be described. First, address discharge is performed by applying a predetermined voltage to the scan electrode 22 and the address electrode 32 corresponding to the discharge cell 36 to be lit. Thereby, wall charges are formed in the discharge cells 36 corresponding to the display data. Thereafter, when a sustain discharge voltage is applied between the sustain electrode 23 and the scan electrode 22, a sustain discharge occurs in the discharge cell 36 in which wall charges are formed, and ultraviolet rays are generated. The discharge cells 36 are turned on when the phosphors in the red phosphor layer 35R, the green phosphor layer 35G, and the blue phosphor layer 35B excited by the ultraviolet light emit light. An image is displayed by a combination of lighting and non-lighting of the discharge cells 36 of each color.

  Next, the structure of the back plate 30 of the PDP 10 and the manufacturing method thereof will be described with reference to FIG. FIG. 3 is a cross-sectional view showing the configuration of the back plate 30 of the PDP 10. A plurality of address electrodes 32 are formed in stripes on the back glass substrate 31 by screen-printing and baking a silver paste for electrodes. A base dielectric layer 33 is formed by applying and baking a paste containing a glass material so as to cover these address electrodes 32 by a die coater method or a screen printing method.

  A partition wall 34 is formed on the underlying dielectric layer 33 thus formed. As a method for forming the partition wall 34, there is a method in which a paste containing a glass material is repeatedly applied in a stripe shape with the address electrodes 32 sandwiched by a screen printing method and baked. There is also a method of covering the address electrodes 32, applying a paste on the underlying dielectric layer 33, patterning and baking. A discharge space is partitioned by the barrier ribs 34, and discharge cells 36 are formed. The gap between the partition walls 34 is set to 130 μm to 240 μm in accordance with, for example, a 42-inch to 50-inch full HD television or an HD television.

  A red phosphor layer 35R, a green phosphor layer 35G, a paste containing particles of each phosphor material are applied to the grooves between the two adjacent barrier ribs 34 by a screen printing method or an ink jet method, and fired. A blue phosphor layer 35B is formed.

  The back plate 30 thus manufactured and the front plate 20 on which the display electrode pair 24, the dielectric layer 25, and the protective layer 26 are formed are respectively connected to the scanning electrode 22 of the front plate 20 and the address electrode of the back plate 30. The front plate 20 and the back plate 30 are sealed by applying the sealing glass to the peripheral portion so as to be opposed to each other so as to be orthogonal to each other. Then, once the discharge space is evacuated to a high vacuum, a mixed gas such as neon (Ne) and xenon (Xe) is sealed at a pressure of 55 kPa to 80 kPa, and the PDP 10 of this embodiment is manufactured.

  A plasma display device is obtained by connecting the drive circuit 40 to the PDP 10 thus manufactured and further arranging a housing or the like.

  Next, an example in which such a plasma display device is applied to a stereoscopic image display device will be described. 4A is a perspective view showing an example of a stereoscopic image display device using a plasma display device, and FIG. 4B is a video viewing glasses used when viewing a video displayed by the stereoscopic image display device. It is a perspective view which shows the external appearance. A viewer can view a video displayed on the display surface of the stereoscopic image display device as a stereoscopic video by viewing the video through glasses for video viewing.

  In FIG. 4, a synchronization signal transmission unit 110 of the stereoscopic image display apparatus 100 using the plasma display device transmits a signal synchronized with the video output to the display surface, and the synchronization signal reception unit 130 of the video viewing glasses 120 Receive. The video viewing glasses 120 performs predetermined optical processing on the light incident on the left and right eyes based on the synchronization signal. Thereby, the viewer wearing the video viewing glasses 120 can view the video displayed on the stereoscopic image display device 100 as a stereoscopic video.

  When the video viewing glasses 120 include a liquid crystal shutter, an infrared emitter is used as the synchronization signal transmitting unit 110 of the stereoscopic image display apparatus 100, and an infrared sensor is used as the synchronization signal receiving unit 130 of the video viewing glasses 120. Can be used.

  That is, the stereoscopic image display device 100 is configured by combining the above-described plasma display device and video viewing glasses 120 using a liquid crystal shutter that opens and closes at a frequency of 120 Hz. The three-dimensional video (3D video) is subjected to a predetermined process, and the video for the left eye and the video for the right eye are displayed with different video by the amount of parallax. The viewer can perceive parallax from the video viewed with the left eye and the right eye and perceive that the video displayed on the stereoscopic image display apparatus 100 is a stereoscopic video.

  Here, in the stereoscopic image display apparatus 100, it is necessary to prevent crosstalk, which is a phenomenon in which an image looks double, even if the liquid crystal shutter is opened and closed at a frequency of 120 Hz. For that purpose, if the afterglow time of the light emitted from each color phosphor of the PDP is 3.5 msec or less, particularly 3.0 msec or less, a stereoscopic image display that is easy on the eyes can be realized, and further powerful. The accompanying stereoscopic video can be viewed.

  Next, the phosphor used in the plasma display device of the present invention will be described.

The inventors of the present invention have known that Eu ³⁺ -activated rare earth phosphovanadate phosphor crystals are incomplete, the light emission characteristics are changed by heat treatment for several hours in the atmosphere at about 1500 ° C., and afterglow I found it to be shorter. Moreover, it was found that the short afterglow equivalent to Eu ³⁺ activated rare earth ^{phosphovanadate} phosphor can be realized by thorough optimization of manufacturing conditions. Furthermore, it has been found that a large phosphorus ratio has a positive effect on luminance saturation as well as luminance and phosphor stability under VUV excitation. As a result, a 3D plasma using a rare earth phosphovanadate phosphor is obtained. It was also found that the problems that occurred in the display device could be solved.

  Here, “phosphorus ratio”, “first sub-light-emitting component ratio”, “second sub-light-emitting component ratio”, and “1/10 afterglow time” are defined as follows.

Phosphorus ratio (at.%):
It means the ratio of the number of phosphorus atoms to the total number of phosphorus and vanadium atoms contained in the rare earth phosphovanadate phosphor. The number of atoms of phosphorus and vanadium is quantitatively analyzed by ICP emission spectroscopy (for example, using SRS1700VR manufactured by SII).

First sub-luminescence component ratio:
In the spectral distribution of red light emitted from the phosphor when excited by VUV, it means the ratio of the peak height of the sub-light emitting component near 614 nm to the peak height of the main light emitting component near 619 nm.

Second sub-luminescence component ratio:
In the spectral distribution of red light emitted by the phosphor when excited by VUV, it means the ratio of the peak height of the auxiliary light emitting component near 697 nm to the peak height of the main light emitting component near 619 nm.

1/10 afterglow time (msec):
After completely irradiating the phosphor with the excitation light, when the phosphorescence intensity after a certain period of time is 100 and the elapsed time is the reference time (t ₀ = 0), this phosphorescence intensity is 1/10. This means the time until the value decreases to 10. For convenience of measurement, the 1/10 afterglow time of the phosphor powder is the afterglow characteristic of the phosphor after the shutter provided on the excitation light source side is closed after irradiating the phosphor with an ultraviolet ray having a wavelength of 250 nm (time change of light). ). It has been confirmed that the same results can be obtained qualitatively even when the phosphor powder is irradiated with VUV instead of ultraviolet light having a wavelength of 250 nm.

The spectral distribution (emission spectrum) is determined by irradiating VUV to a phosphor sample (room temperature) placed in a vacuum of 10 ⁻⁴ Pa using an excimer lamp (USHIO INC., Peak 146 nm) as a VUV excitation light source. A multi-channel photodetector (for example, C-7473 (Hamamatsu Photonics)) having a 1024 ch electronically cooled CCD linear image sensor as a detection element, measurement wavelength range: 200 to 950 nm, element resolution: about 0.8 nm )) Is obtained by calculation from data obtained using a multichannel spectrophotometer. More specifically, spectral distribution data obtained by the multi-channel spectrophotometer is approximately calculated on software to obtain a spectral distribution obtained by connecting data every 1 nm in the wavelength range of 350 to 750 nm. The total number of photons is obtained by calculation from the spectral distribution. In the spectral distribution, the height of the main emission peak near 619 nm of the rare earth phosphovanadate phosphor emitting red light is 100 times or more the background noise intensity.

  In addition, the 1/10 afterglow time of the phosphor powder is obtained by using, for example, a spectrofluorometer (FP-6500: JASCO Corporation) and using dedicated software (“phosphorescence lifetime measurement” of “Spectrum Manager”). It is understood by using. Specific examples of measurement conditions are excitation bandwidth: 1 nm, fluorescence bandwidth: 20 nm, sensitivity: Low, excitation wavelength: 250.0 nm, fluorescence wavelength: 619.0 nm, delay time: 0.0 msec, measurement time: 25 msec. Data capture interval: 0.1 msec. The 1/10 afterglow time is, for example, 7.0 msec after the start of data acquisition, where the shutter on the excitation light source side is closed and the afterglow characteristics of the phosphor powder can be monitored. The elapsed time is obtained from the afterglow characteristics up to 25.0 msec after the start of data acquisition, with the elapsed time as a reference time (t = 0).

  For reference, a specific example of the afterglow characteristic evaluation data of the phosphor powder is shown in FIG. In FIG. 5, the horizontal axis represents the data acquisition time, and the time after opening the shutter provided on the excitation light source side (maximum 25 msec) is shown in real scale. The vertical axis shows the emission intensity (data capture interval: 0.1 msec) captured by the detector in actual scale. FIG. 5 shows that the shutter starts to open at the time of 0 msec, the shutter starts to close at the time of about 5 msec, and the afterglow characteristic of the phosphor sufficiently long with respect to the shutter closing speed is detected after the time of about 6 msec. It shows how it can be regarded as being taken in by the vessel.

In the present invention, the 1/10 afterglow time (t _AG ) of the phosphor powder is the time after 7.0 msec from the start of data acquisition in the measurement data shown in FIG. was the reference time (t ₀ = _0), as 100 the emission intensity at the reference time (t _0), the luminous intensity is defined as the time until the decrease of 10.

Next, the characteristics commonly recognized in Eu ³⁺ activated rare earth phosphovanadate phosphors having different phosphorus ratios are shown in the above YPV red phosphor, that is, the compound (Y _1-x Eu _x ) (P _y V _1-y ) The case of a phosphor composition mainly composed of O ₄ will be outlined as an example.

  FIG. 6 is a diagram showing the relationship between the phosphorus ratio of the YPV red phosphor, the luminance relative value (a), and the total photon number relative value (b). FIG. 7 is a diagram showing emission spectra of YPV red phosphors having different phosphorus ratios. In FIG. 7, (a), (b), (c), (d), (e), (f), (g), (h), (i), (j), (k), And (l), respectively, when the phosphorus ratio is 0 at%, 10 at%, 20 at%, 30 at%, 40 at%, 50 at%, 60 at%, 65 at%, 70 at%, 80 at%, 90 at%, and 100 at% Indicates.

  FIG. 8 is a diagram showing afterglow characteristics of YPV red phosphors having different phosphorus ratios. In FIG. 8, (a), (b), (c), (d), (e), and (f) each have a phosphorus ratio of 0 at%, 20 at%, 40 at%, 60 at%, The cases of 80 at% and 100 at% are shown.

FIG. 9 is a diagram showing the luminance saturation phenomenon of the YPV red phosphor in which the phosphorus ratio is in the range of 40 to 100 atomic%. Note that FIG. 9 shows that the YPV red phosphor and the BAM (BaMgAl ₁₀ O ₁₇ : Eu ²⁺ ) blue phosphor are irradiated with VUV (wavelength 146 nm) having different intensities, and the luminance of the BAM blue phosphor is 100, respectively. It is the figure which normalized the brightness | luminance of the fluorescent substance, and also normalized the brightness | luminance at the time of exciting with the weakest VUV as 100, and is the figure which put together the vertical axis | shaft as a relative luminance value and the horizontal axis as a relative value of VUV intensity. . In FIG. 9, (a), (b), (c), and (d) show the cases where the phosphorus ratio is 40 at%, 60 at%, 80 at%, and 100 at%, respectively (e) Is data of the BAM blue phosphor used as a reference.

  As shown in FIG. 6, the luminance relative value and the total photon number relative value of the YPV red phosphor increase as the phosphorus ratio increases, and gradually decrease after the phosphorus ratio reaches the maximum at 65 to 80 atomic%. To do. That is, the luminance of YPV having a phosphorus ratio of 70 atomic% or less decreases as the phosphorus ratio decreases, and increases as the phosphorus ratio increases.

  As can be seen from FIG. 7, in the emission spectrum of the YPV red phosphor, as the phosphorus ratio is increased, the first sub-light-emitting component ratio decreases, and the second sub-light-emitting component ratio and the sub-light-emitting component near 593 nm. The ratio (hereinafter referred to as the third sub-light emitting component ratio) increases. As can be seen from FIG. 7, the first sub-light-emitting component ratio and the second (and third sub-light-emitting component ratio) are contradictory.

  Further, as can be seen from FIG. 8, the afterglow of YPV becomes longer as the phosphorus ratio increases.

  As can be seen from the comparison between FIG. 7 and FIG. 8, when the phosphorus ratio is increased to the YPV with the second and third sub-light emission component ratios increased, the 1/10 afterglow time of the red light Is widely known to be long.

  Moreover, as shown in FIG. 9, the YPV red phosphor has a problem that the luminance is saturated when excited with VUV having a high excitation density. At least in the YPV red phosphor having a phosphorus ratio of 40 atomic% or more, when the phosphorus ratio increases, luminance saturation is suppressed. Although the data is omitted, this tendency is qualitatively similar when the vertical axis in FIG. 9 is the total number of photons.

  Note that luminance saturation of YPV under VUV excitation is a problem raised by the inventors for the first time.

  From the experimental results of FIGS. 6 to 9, the inventors have a range of 40 to 80 atomic% for realizing a red phosphor having all of high luminance, short afterglow, and luminance saturation suitable for 3D-PDP. It was found that the technical point is how much short persistence can be realized with a relatively high phosphorus ratio in the YPV.

  In addition, when obtaining the 3D-PDP in which the crosstalk is not substantially recognized using the YPV phosphor widely known through the characteristic evaluation of the obtained YPV mass production prototype and the prototype evaluation of the PDP. It has been found that YPV with a phosphorus ratio of about 60 atomic% is preferred.

  As can be seen from FIGS. 6, 8, and 9, the YPV having a phosphorus ratio of about 60 atomic% has a brightness level that is about 6% lower than the YPV having a phosphorus ratio of about 70 to 80 atomic%. Furthermore, although the luminance saturation characteristic is inferior, the 1/10 afterglow characteristic shows a short afterglow of less than 4 msec. For this reason, the upper limit of the phosphorus ratio that is effective in suppressing the crosstalk, which is essential in 3D-PDP, is about 60 atomic%.

  As described above, the YPV red phosphor that satisfies the requirements for 3D-PDP is YPV whose upper limit of the phosphorus ratio is about 60 atomic%, and the necessity of sacrificing the luminance level and the like has arisen.

  Hereinafter, the knowledge found in the search for the performance improvement of the YPV red phosphor will be described.

  The characteristics shown in FIG. 10 and FIG. 11 below are characteristics that are recognized in a mass production prototype level YPV red phosphor having characteristics that satisfy the practical level. This is a characteristic of a phosphor that can be regarded as YPV that is enhanced to the limit.

  FIG. 10 is a graph showing the afterglow characteristics before (a) and after (b) heating the conventional YPV red phosphor in the atmosphere at 1500 ° C. for 2 hours.

FIG. 11 is a diagram showing the afterglow characteristics of a conventional YPV red phosphor having a different composition, shown for reference. (A) and (b) each have a phosphorus ratio of 67 atomic%. This is data of the composition (Y _0.92 Eu _0.08 ) (P _0.67 V _0.33 ) O ₄ and the composition (Y _0.96 Eu _0.04 ) (P _0.61 V _0.39 ) O ₄ having a phosphorus ratio of 61 atomic%.

For example, as shown in FIG. 10, a conventionally known Y (P, V) O ₄ : Eu ³⁺ red phosphor has a short afterglow accompanied by a slight change in emission spectrum by at least the heat treatment at 1500 ° C. To do.

  As shown in FIG. 11, the 1/10 afterglow time with a phosphorus ratio of 67 atomic% is about 3.4 to 3.5 msec, and about 3.3 to 1/10 afterglow with a phosphorus ratio of 61 atomic%. It is longer than 3.4 msec.

  Although data is omitted, a large difference in 1/10 afterglow time due to a difference in Eu activation amount is hardly recognized.

  As can be seen from FIG. 10, the 1/10 afterglow time before the heat treatment is 3.3 to 3.4 msec, whereas after the 1500 ° C. heat treatment, it is 3.2 to 3.3 msec. An afterglow of about 3% is observed. Moreover, the same tendency is recognized also in other YPV red fluorescent substance to some extent.

  In addition, in the quantitative analysis of the phosphor constituent elements by ICP emission spectroscopy, at least a decrease in the phosphorus ratio is not observed, and a relatively large amount of metal impurities is not observed.

  Considering that YPV is usually mass-produced at a firing temperature of 1050 to 1350 ° C., the above results are practical applications that have been sufficiently improved in terms of completeness by optimizing manufacturing conditions for a long time in the past. Even a level of YPV phosphor is believed to suggest that crystals are incomplete and still leave room for improvement.

  At the same time, through thorough optimization of manufacturing conditions, a short persistence equivalent to that of YPV red phosphors that have been practically studied for 3D-PDP can be realized with a larger phosphorus ratio than previously known. It suggests the possibility.

  Further, by comparison with FIG. 8, the short persistence of about 3% of YPV having a phosphorus ratio of about 60 atomic% has a short afterglow equivalent to that before heat treatment by increasing the phosphorus ratio of about 5 atomic%. It suggests the possibility of realization.

  Hereinafter, embodiments of the rare earth phosphovanadate phosphor of the present invention will be described.

The rare earth phosphovanadate phosphor of the present invention is a rare earth phosphovanadate phosphor activated by Eu ³⁺ , and emits red light emitted by the phosphor when excited by vacuum ultraviolet light having a wavelength of 146 nm. In the component, the peak height of the sub-light-emitting component near 614 nm with respect to the peak height of the main light-emitting component near 619 nm is defined as the first sub-light-emitting component ratio, and the sub-light-emitting component near 697 nm with respect to the peak height of the main light-emitting component. When the peak height is defined as a second sub-light-emitting component ratio, the first sub-light-emitting component ratio and the second sub-light-emitting component ratio are 35.0% or more and less than 41.5%. To do.

  In a preferred embodiment of the rare earth phosphovanadate phosphor of the present invention, when the ratio of the number of phosphorus atoms to the total number of phosphorus and vanadium atoms is defined as the phosphorus ratio, the phosphorus ratio is more than 62 atom% and less than 70 atom%. , Preferably 63 atomic percent or more and less than 68 atomic percent. More preferably, the ratio of the second sub-light emitting component is 36.0% or more, and more preferably 38.0% or more.

Such Eu ³⁺ activated rare earth ^{phosphovanadate} phosphors emitting red light can be expected to have high brightness under VUV excitation, and have relatively high phosphorus in the range of more than 60 atomic% and less than 70 atomic%. Excellent in crystal quality by a ratio, so that it exhibits high light emission performance, and has characteristics preferable as a red phosphor for 3D-PDP, such as high luminance, short afterglow, and luminance saturation-less under VUV excitation. Become.

Further, when the composition has the same phosphorus ratio as the conventional one, the ratio of the third auxiliary light emitting component is relatively smaller than that of the conventional Eu ³⁺ activated rare earth ^{phosphovanadate} phosphor, and the red purity. In addition to being a phosphor that emits good red light, the second (and third) sub-light-emitting component ratio is small, so that the phosphor has a relatively short persistence.

As a result, it is possible to provide an Eu ³⁺ activated rare earth phosphovanadate phosphor that has both high brightness, good color tone of red light, and short persistence.

Conversely, in the case of obtaining the red light color tone and afterglow to desired than conventional Eu ³⁺ activated rare earth phosphonium vanadate phosphor, as some phosphorus ratio is large composition, Eu ^{3 +} Activated rare earth phosphovanadate phosphors can also be constructed.

At this time, as can be seen from FIG. 6 described above, the Eu ³⁺ -activated rare earth ^{phosphovanadate} phosphor has a higher luminance under VUV excitation and a higher total photon number, and the valence of ions. Since the proportion of vanadium which is unstable in terms of number is reduced, it becomes an Eu ³⁺ activated rare earth ^{phosphovanadate} phosphor with little phosphor deterioration during the manufacturing process of the PDP and driving of the PDP. Furthermore, as can be seen from FIG. 10, a luminance saturation-less Eu ³⁺ activated rare earth ^{phosphovanadate} phosphor that emits red light with a high luminance level even under high-density VUV excitation conditions.

As a result, an Eu ³⁺ activated rare earth ^{phosphovanadate} phosphor having both stability and higher brightness can be provided.

The rare earth phosphovanadate phosphor of the present invention is substantially a compound represented by the chemical formula of (Ln _1-x Eu _x ) (P _y V _1-y ) O ₄ , where Ln is Sc, Y And a rare earth containing at least Y, and x is preferably a numerical value satisfying 0.01 ≦ x ≦ 0.1, preferably 0.03 ≦ x ≦ 0.08. The y is a numerical value satisfying 0.62 <y <0.70, preferably 0.63 ≦ y <0.68.

  In this way, the phosphor ratio of 65 to 80 atomic% at which the luminance is maximum or YPV close to this is obtained, so that a red phosphor with relatively high emission intensity under VUV excitation and less luminance saturation is obtained.

  The rare earth phosphovanadate phosphor of the present invention is not particularly limited in terms of particle shape. When the material has a substantially spherical particle shape, it becomes a phosphor capable of forming a dense phosphor film, and thus is preferable for a light emitting device.

  On the other hand, if irregularly shaped particles have agglomerated particle shape, they can be manufactured relatively easily by a solid-phase reaction of premixed raw material powder, and no special considerations are required for manufacturing. This is preferable.

  The rare earth phosphovanadate phosphor of the present invention is preferably a phosphor produced by a reaction time exceeding 10 minutes.

  Since such rare earth phosphovanadate phosphors are formed after a long reaction time, the crystal completeness is greater, and as described above, good red light is obtained in terms of red purity. The phosphor becomes excellent in terms of short persistence. In addition, for example, when obtaining a desired color tone and afterglow of red light, it is possible to increase the phosphor ratio, combine stability and higher brightness, and do not easily saturate even under high-density VUV excitation. Become a body.

  Further, in the rare earth phosphovanadate phosphor of the present invention, the 1/10 afterglow time of the red light emitted from the phosphor is shorter than 3.4 msec, and preferably 3.3 msec or less.

  Such a rare earth phosphovanadate phosphor is preferable for 3D-PDP and suppresses the double reflection phenomenon (crosstalk) of 3D-PDP images.

  Moreover, since the rare earth phosphovanadate phosphor of the present invention has high crystal perfection, it is excellent in terms of performance and stability. Further, afterglow characteristics equivalent to those of the prior art can be realized with a relatively high phosphorus ratio, which can be excellent in terms of luminance and luminance saturation characteristics.

The present invention has been achieved by finding that the Eu ³⁺ -activated rare earth ^{phosphovanadate} phosphor specified by the emission spectrum shape exhibits the overall excellent characteristics as described above. Accordingly, the Eu ³⁺ activated rare earth ^{phosphovanadate} phosphor containing at least both phosphorus and vanadium is not particularly limited. For example, phosphors in which some of the constituent elements are replaced with other elements, phosphors containing a trace amount of metal impurities (for example, Tb) on the order of several ppm to several percent, and compounds such as SiO _{2 that} can be used as sintering aids. Needless to say, there are various modifications such as a phosphor added in a small amount, a phosphor slightly deviating from the stoichiometric composition, and a phosphor whose particle surface is coated with another substance.

  Next, a method for producing the rare earth phosphovanadate phosphor of the present invention will be described.

  The rare earth phosphovanadate phosphor of the present invention can be produced by a solid-phase reaction of raw material powders mixed in advance.

  As a raw material, it is sufficient to appropriately select a material containing rare earth, a material containing phosphorus, or a material containing vanadium.

The substance containing rare earths can be selected from metallic rare earths or rare earth compounds, but it is preferable to use rare earth oxides that are easily available and handled. The rare earth oxides include Sc ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , Eu ₂ O ₃ , Gd ₂ O ₃ , Lu ₂ O ₃ , (Y, Eu) ₂ O ₃ , (Gd, Eu) ₂ O ₃ , (Y, Sc, Eu) ₂ O ₃ , (Y, Gd, Eu) ₂ O _{3, and the} like are appropriately selected and used.

  In addition to rare earth oxides, rare earth carbonates, rare earth oxalates, rare earth nitrates, rare earth halides, and the like can be used.

The substance containing phosphorus can be selected from metallic phosphorus or phosphorus compounds, but it is preferable to use ammonium phosphates (such as (NH ₄ ) ₂ HPO ₄ ) that are easy to obtain and handle.

In addition, the said phosphorus compound can also utilize liquid phosphorus compounds, such as phosphoric acid. The substance containing vanadium can be selected from metal vanadium or a vanadium compound, but it is preferable to use vanadium oxide (such as V ₂ O ₅ ) or an ammonium salt of vanadate (NH ₄ VO ₃ ) that is easy to obtain and handle.

A composite compound containing a plurality of elements selected from rare earth, phosphorus and vanadium can also be used. Specific examples of the composite compound include rare earth phosphates (such as YPO ₄ and (Y, Eu) PO ₄ ), rare earth vanadates (such as YVO ₄ and (Y, Eu) VO ₄ ), and vanadium phosphate (VPO). ₃ etc.).

Moreover, a reaction accelerator is utilized as needed. The reaction accelerator can be selected from substances containing boron and alkali metals, such as boron compounds (such as H ₃ BO ₃ and B ₂ O ₃ ) and alkali metal compounds (particularly alkali metal carbonates (Li ₂ CO _3)). , Na ₂ CO ₃ , K ₂ CO _3, etc.), alkali metal nitrates (LiNO ₃ , NaNO ₃ , KNO _3, etc.), vanadates containing alkali metals (eg NaVO ₃ ), phosphates containing alkali metals ( For example, NaH ₂ PO ₄ ) can be used.

  Next, the above raw materials are weighed, prepared and mixed so that a phosphor with a stoichiometric composition or an atomic ratio close to this is obtained.

  The mixing may be dry mixing or wet mixing, but wet mixing is preferable for the purpose of obtaining a mixed raw material having a good mixing state. The mixed raw material can be used as a slurry or a solution. In addition, when wet-mixing is performed, it is preferable to prepare a dry raw material in advance by, for example, a drying process.

  About a mixed raw material, temporary baking (decomposition baking) is performed as needed, and elements (for example, hydrogen, nitrogen, carbon, etc.) originally unnecessary are removed beforehand.

  When the mixed raw material is charged into a firing container and the mixed raw material is heated, a rare earth phosphovanadate phosphor is generated by a solid phase reaction.

  The method for producing a rare earth phosphovanadate phosphor of the present invention is not particularly limited as long as it is a solid phase reaction that improves the crystallinity of the rare earth phosphovanadate phosphor. The reaction time of the reaction is preferably more than 10 minutes, more preferably more than 1 hour. In this way, since the reaction time is long, the completeness of the crystal is enhanced, and as described above, phosphors that emit good red light in terms of color purity and are excellent in terms of short afterglow, or phosphorus ratio Therefore, a phosphor having both stability and higher brightness and luminance saturation resistance is synthesized.

  Since the manufacturing method using such a solid-phase reaction is an orthodox fluorescent material manufacturing method, the shape of the phosphor particles is an agglomeration of irregularly shaped particles. It can be manufactured relatively easily and is preferable in terms of industrial production. In order to obtain a phosphor with a relatively small particle size (center particle size: 1 to 5 μm) for the purpose of application to a PDP or a cold cathode fluorescent lamp (CCFL), the firing temperature is compared. Production at a low temperature of 1050 ° C. or higher and lower than 1300 ° C. is desired. On the other hand, for the purpose of obtaining a phosphor having a relatively large particle size (center particle size: 5 to 20 μm) for the purpose of application to a fluorescent lamp or an electron tube, the firing temperature is a relatively high temperature of 1300 ° C. or more and less than 1600 ° C. Is desired.

  In general, when the firing temperature is set to a relatively low temperature of 1050 ° C. or more and less than 1300 ° C., it takes a relatively long time to sufficiently react the phosphor raw material. It's time. In addition, when the firing temperature is set to a relatively high temperature of 1300 ° C. or more and less than 1600 ° C., the firing time may be a relatively short time, for example, 1 to 5 hours.

  When a reaction accelerator is used, it is mixed in a small amount or a small amount (about 0.01 mol% to 30 mol% with respect to 1 mol of the phosphor) in the raw material, the calcined product, or the precursor before the main baking. As the amount of the reaction accelerator is increased, the phosphor can be synthesized at a lower temperature. On the other hand, the elements constituting the reaction accelerator are mixed as impurities, and the desired rare earth phosphovanadate fluorescence is obtained. There is an increased risk that the body cannot be manufactured. For this reason, when the firing temperature is set to a relatively high temperature of 1300 ° C. or more and less than 1600 ° C., the reaction accelerator may be added in a small amount of 0.1 mol% or less with respect to 1 mol of the phosphor. Preferably, no reaction accelerator is used.

  On the other hand, when the firing temperature is set to a relatively low temperature of 1050 ° C. or higher and lower than 1300 ° C., the amount is preferably 0.1 mol% or more and 100 mol% or less with respect to 1 mol of the phosphor.

  In addition, when an unnecessary substance is generated after firing, such as when firing using a reaction accelerator, it is appropriately removed by washing with acid, alkali, warm water, or the like.

  Next, specific examples will be described.

  The characteristics of the rare earth phosphovanadate phosphor of the present invention will be described together with the production method of the present invention, which is produced by an orthodox solid phase reaction with a comparative example.

  As a specific example of the rare earth phosphovanadate phosphor, a general YPV red phosphor was selected.

As a raw material of the YPV red phosphor, a predetermined amount of compound powder shown below was used, and for convenience, the mixing ratio was such that the phosphor composition was (Y _0.92 Eu _0.08 ) (P _0.67 V _0.33 ) ₄ .

Yttrium oxide (Y ₂ O ₃ ): 20.92 g
Europium oxide (Eu ₂ O ₃ ): 2.82 g
Diammonium phosphate ((NH ₄ ) ₂ HPO ₄ ): 17.70 g
Vanadium pentoxide (V ₂ O ₅ ): 6.02 g
Using a motor grinder, these raw materials were sufficiently wet mixed with an appropriate amount of water (pure water).

  The mixed raw material after wet mixing was transferred to an evaporating dish and dried at 120 ° C. overnight using a dryer. The mixed raw material after drying was roughly crushed and then calcined in the atmosphere at 500 ° C. for 2 hours.

  The calcined product was sufficiently pulverized using a motor grinder to obtain a calcined raw material.

The fired raw material is transferred to an alumina crucible with a lid, and fired in an atmosphere of 1300 ° C., 1400 ° C., and 1500 ° C. for 2 hours using a box-type electric furnace, and Eu ³⁺ activated rare earth phosphovanadate. A salt phosphor Y (P, V) O ₄ : Eu ³⁺ red phosphor was obtained. For simplification of the experiment, post-processing was omitted.

Here, Eu ³⁺ -activated rare earth ^{phosphovanadate} phosphors obtained by firing in air at 1300 ° C., 1400 ° C., and 1500 ° C. for 2 hours are Comparative Example 1, Comparative Example 2, and It is a YPV red phosphor of an example.

FIG. 12 shows the vicinity of the main peak of the XRD pattern of the YPV red phosphor obtained by firing at different firing temperatures. For reference, FIG. 12 also shows the main peak positions of the XRD pattern of the compound YVO ₄ containing no phosphorus and the compound YPO ₄ containing no vanadium, calculated from PDF (Powder Diffraction Data).

In FIG. 12, (a), (b), and (c) are XRD patterns when the firing temperatures are 1300 ° C., 1400 ° C., and 1500 ° C., respectively, and (d) and (e) are respectively , XRD pattern main peak positions of compound YVO ₄ and compound YPO ₄ .

  FIGS. 13 and 14 show the emission spectrum and afterglow characteristics of YPV whose XRD pattern is shown in FIG. 13 and 14, (a), (b), and (c) are data when the firing temperature is 1300 ° C., 1400 ° C., and 1500 ° C., respectively.

  Note that the emission spectrum of FIG. 13 is an enlarged summary of those normalized with the emission peak near 619 nm as 100.

  As shown in FIG. 12, when the firing temperature is low, the main XRD peak position near 25.5 ° is located on the wide angle side, and the main XRD peak has a shape having a relatively large shoulder on the narrow angle side. As a result, the half width of the XRD peak is increased. As the firing temperature is increased, at the firing temperature up to 1500 ° C., the main XRD peak position shifts to the narrow-angle side, the shoulder recognized on the narrow-angle side of the main XRD peak decreases, and the half width of the XRD peak decreases.

  As can be seen by comparing FIG. 12 with FIG. 13 and FIG. 14, with the narrow angle side shift of the main XRD peak position and the decrease in shoulders observed on the narrow angle side of the main XRD peak, the second and second The sub-light-emitting component ratio of 3 gradually decreases, resulting in a short afterglow.

In the composition analysis by ICP emission spectroscopy, at a firing temperature up to 1500 ° C., the composition is almost similar to (Y _0.92 Eu _0.08 ) (P _0.69 V _0.31 ) ₄ of about 69 atomic%, which is slightly higher than the charged composition. However, almost no change in the actual composition due to the difference in the firing temperature was observed.

From the comparison between the main XRD peak positions of Compound YVO ₄ and Compound YPO ₄ shown in (d) and (e) of FIG. 12 and the data shown in (a) to (c) of FIG. 12, Y (P, V ) O ₄ : Eu ³⁺ red phosphor has insufficient solid solution of YVO ₄ : Eu ³⁺ and YPO ₄ : Eu ³⁺ when the reaction conditions are poor, for example, because the firing temperature is low. It can be seen that the crystals are incomplete. From the comparison between the data shown in FIG. 12 and the data shown in FIG. 13 and FIG. 14, the Y (P, V) O ₄ : Eu ³⁺ red phosphor has a poor reaction condition and is incompletely crystallized. It can be said that the ratio of the second (and third) sub-light-emitting component is increased, resulting in longer afterglow.

  Furthermore, the YPV red phosphor (example) fired at 1500 ° C. shown in FIG. 14C has a relatively high actual phosphorus ratio of 69 atomic%, and the phosphorus ratio shown in FIG. Although an afterglow time larger than that of the conventional YPV red phosphor of Comparative Example 3 is expected, the 1/10 afterglow time is about 3.3 msec, and the phosphorus ratio is 67 atomic%. 1/10 afterglow time (3.4 to 3.5 msec) of the conventional YPV red phosphor.

  The conventional YPV red phosphor (Comparative Example 4) having afterglow characteristics shown in FIG. 11B has a phosphorus ratio of 61 atomic% and a 1/10 afterglow time as short as about 3.3 msec. is there.

  From these results, the shortening of the afterglow accompanying the high-temperature heat treatment of the conventional YPV red phosphor shown in FIG. 10 is a characteristic that proves that the conventional YPV red phosphor is not necessarily perfect in terms of crystallinity. It is believed that there is. Moreover, it can be said that the light emission characteristic of the YPV red phosphor that has been conventionally known is a characteristic that proves that the YPV red phosphor is not a true characteristic originally provided.

This is not limited to Y (P, V) O ₄ : Eu ³⁺ red phosphor, but Eu ³ containing at least both phosphorus and vanadium to some extent due to the similarity of physical properties of materials. It is clear that this is a property common to ⁺ activated rare earth phosphovanadate phosphors.

  In addition, even in a production method using a reaction accelerator, it is sufficiently expected that such a YPV red phosphor can be realized by thoroughly optimizing production know-how and production conditions.

  Note that such rare earth phosphovanadate phosphors having high crystal perfection have high crystal perfection, and are excellent in performance and stability. Although the data is omitted, for example, the decrease in 1/10 afterglow time associated with the heat treatment in the atmosphere at 1500 ° C. for 2 hours is less than 0.1 msec, and the characteristic fluctuation is small even when heating at high temperature. Further, the X-ray diffraction pattern has a feature that the half width of the main diffraction peak having a peak at a diffraction angle 2θ of about 25.5 ° is narrower than 0.09 °, particularly 0.08 °.

  In addition, since the afterglow characteristics equivalent to those of the prior art can be realized with a relatively high phosphorus ratio, when the short afterglow characteristics are made equal, it can be excellent in terms of luminance and luminance saturation characteristics.

  FIG. 15 is a diagram showing the luminance saturation of the YPV red phosphor fired at 1500 ° C. shown in FIG. 15, (a) and (b) respectively show the luminance saturation characteristics of the YPV red phosphor fired at 1500 ° C. shown in FIG. 14 (c) and the conventional YPV with the phosphorus ratio of 61 atomic%. FIG.

In FIG. 15, in order to more clearly show the difference from the conventional (Y _0.96 Eu _0.04 ) (P _0.61 V _0.39 ) O ₄ having a phosphorus ratio of 61 atomic%, each YPV red phosphor is represented by the weakest VUV. Normalization by luminance when excited with is not performed.

  That is, similarly to the case described with reference to FIG. 15 above, VUV (wavelength 146 nm) having different intensities is irradiated to the YPV red phosphor and the BAM blue phosphor, and the luminance level of the BAM blue phosphor is used as a reference. First, the brightness of the conventional YPV having a phosphorus ratio of 61 atomic% is plotted, and the brightness level of the YPV red phosphor fired at 1500 ° C. with respect to the conventional YPV red phosphor is plotted. In FIG. 15, the vertical axis represents the luminance relative value, but the same tendency is recognized even when the vertical axis represents the total number of photons.

  As shown in FIG. 15, the YPV red phosphor fired at 1500 ° C. has a relative luminance (and total photon number) as compared with the conventional YPV (comparative example 4) having a phosphorus ratio of 61 atomic%. And high efficiency (good wavelength conversion efficiency of VUV to red light). Further, there is little luminance saturation when the excitation intensity of VUV is increased, and the luminance level difference under high-density UVU excitation is further increased. These advantages seen with the YPV red phosphor fired at 1500 ° C. are believed to be due to the relatively high phosphorus percentage.

  These afterglow characteristics are as shown in FIG. 10 and FIG.

  FIG. 16 shows the spectral distribution of the YPV red phosphor of the example.

  The rare earth phosphovanadate phosphors of the examples with high crystal perfection have not only the reason, but the first side emission near 613 nm as well as the ratio of the second side emission component near 698 nm. The component ratio also tends to be relatively small compared to YPV having the same phosphorus ratio, and both examples of the first sub-light-emitting component ratio and the second sub-light-emitting component ratio in the spectral distribution are both It was in the range of 35.0% or more and less than 41.5%, particularly 38.0% or more and less than 41.5%.

  For reference, FIG. 17 shows, based on the emission spectra of the conventional YPV red phosphors having different phosphorus ratios shown in FIG. The second sub-light emission component ratio was summarized.

  In FIG. 17, (a) and (b) indicate the first sub-light-emitting component ratio and the second sub-light-emitting component ratio, respectively.

  Note that the hatched portion in FIG. 17 is a region where the first sub-light-emitting component ratio and the second sub-light-emitting component ratio are both in the range of 35.0% or more and less than 41.5%. This is a region recognized by the spectral distribution of YPV of the present invention.

  As can be seen from FIG. 17, in the case of the YPV red phosphor prototyped by the conventional manufacturing technique whose emission spectrum is shown in FIG. 13, the first sub-light emission even if the composition of the YPV red phosphor is changed, such as the phosphorus ratio. An emission spectrum in which the component ratio and the second sub-light-emitting component ratio are both in the range of 35.0% or more and less than 41.5% was not recognized.

  Table 1 summarizes the results of a similar examination of the first sub-light-emitting component ratio and the second sub-light-emitting component ratio of the YPV red phosphors (Comparative Examples 5 to 14) that can be obtained as a precaution. It is a table.

  As can be seen from Table 1, most of the YPV red phosphors that can be obtained have a relatively large first sub-light-emitting component ratio of 41.5% or more. None of the two sub-light-emitting component ratios satisfy the condition of being in the range of 35.0% or more and less than 41.5%.

  From the analogy between FIG. 12 and the examples, the YPV red phosphors of Comparative Examples 5 to 14 are YPV red phosphors having a phosphorus ratio of about 50 to 70 atomic%, and in terms of crystallinity. Although not as much as in the examples, it is presumed that the YPV is better than the YPV prototype phosphor shown in FIG.

As described above, according to the present invention, it is possible to realize a Eu ³⁺ activated rare earth ^{phosphovanadate} phosphor that has both high luminance and short afterglow, is stable and hardly causes luminance saturation, and has high luminance. In addition, the present invention is useful for a display device such as a plasma display device capable of displaying a high color gamut.

10 PDP
20 Front plate 21 Front glass substrate 22 Scan electrode 23 Sustain electrode 24 Display electrode pair 25 Dielectric layer 26 Protective layer 30 Back plate 31 Back glass substrate 32 Address electrode 33 Base dielectric layer 34 Partition 35 Phosphor layer 35R Red phosphor layer 35G Green phosphor layer 35B Blue phosphor layer 36 Discharge cell

Claims (7)

A display device using a rare earth phosphovanadate phosphor activated with Eu ³⁺ , wherein the rare earth phosphovanadate phosphor is a red color emitted by a phosphor when excited by vacuum ultraviolet light having a wavelength of 146 nm. In the light component of light, the peak height of the sub-light-emitting component near 614 nm with respect to the peak height of the main light-emitting component near 619 nm is defined as the first sub-light-emitting component ratio, and the sub-light component near 697 nm with respect to the peak height of the main light-emitting component. When the peak height of the light emitting component is the second sub light emitting component ratio, the first sub light emitting component ratio and the second sub light emitting component ratio are 35.0% or more and less than 41.5%. A display device. The display device according to claim 1, wherein a 1/10 afterglow time of the red light emitted from the phosphor is shorter than 3.4 msec. A rare-earth phosphovanadate phosphor activated with Eu ³⁺ , and in the red light component emitted by the phosphor when excited by vacuum ultraviolet light having a wavelength of 146 nm, the peak height of the main light emitting component near 619 nm The peak height of the sub-light-emitting component near 614 nm relative to the first sub-light-emitting component ratio is defined as the first sub-light-emitting component ratio, and the peak height of the sub-light-emitting component near 697 nm relative to the peak height of the main light-emitting component is defined as the second sub-light-emitting component ratio. In this case, the rare earth phosphovanadate phosphor, wherein the first sub-light-emitting component ratio and the second sub-light-emitting component ratio are 35.0% or more and less than 41.5%. 4. The rare earth phosphovanadate phosphor according to claim 3, wherein the phosphorus ratio is more than 62 atomic% and less than 70 atomic% when the ratio of the number of phosphorus atoms to the total number of atoms of phosphorus and vanadium is defined as the phosphorus ratio. . (Ln _1-x Eu _x ) (P _y V _1-y ) O ₄ is a compound represented by the chemical formula, and Ln is selected from Sc, Y, and Gd, and is a rare earth containing at least Y. The rare earth phosphovanadate phosphor according to claim 3, wherein x satisfies 0.01 ≦ x ≦ 0.1 and y satisfies 0.62 <y <0.70. . The rare earth phosphovanadate phosphor according to claim 3, wherein a 1/10 afterglow time of red light emitted from the phosphor is shorter than 3.4 msec. 4. The rare earth phosphovanadate according to claim 3, wherein in the X-ray diffraction pattern, the half width of the main diffraction peak having a peak at a diffraction angle 2θ in the vicinity of 25.5 ° is narrower than 0.08 °. Salt phosphor.

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