JP2009102502A - Fluorescent lamp and liquid crystal display device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the brightness and the chromaticity of a fluorescent lamp used for a back light of a liquid crystal display device. <P>SOLUTION: A blue fluorescent material containing BaMgAl<SB>10</SB>O<SB>17</SB>:Eu<SP>2+</SP>is used as a fluorescent material of the fluorescent lamp. In the BaMgAl<SB>10</SB>O<SB>17</SB>:Eu<SP>2+</SP>being the blue fluorescent material, it is possible to set the light emitting efficiency and the chromaticity within disired ranges, respectively, by controlling heating temperature and heating time within specified ranges, respectively. The BaMgAl<SB>10</SB>O<SB>17</SB>:Eu<SP>2+</SP>has a y value of CIE chromaticity coordinate within a range of 0.053-0.065 as shown by Fig.1 and can set the relative emission efficiency at a high region. Accordingly, a liquid crystal display device having excellent chromaticity and high brightness can be obtained by using a fluorescent lamp using the fluorescent material in the liquid crystal display device. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a fluorescent film, a fluorescent tube using the fluorescent film, and a liquid crystal display device using the fluorescent tube as a backlight.

  The image display apparatus in this patent refers to an apparatus that displays image information by exciting phosphors by applying energy to emit light. This includes a non-self-luminous image display device including a light source as a backlight or a sidelight in a non-luminous display unit such as a liquid crystal. In addition, the image display apparatus includes the entire system in which the liquid crystal or the light source is used as a display unit and a drive device, an image processing circuit, or the like is incorporated to display an image.

  Hereinafter, a liquid crystal display device will be mainly described among the image display devices. In the liquid crystal display device, the light from the light source 5 is guided to the liquid crystal element side by the backlight unit, the light transmission amount of the liquid crystal element 2 is adjusted for each pixel, and red, green, and blue for each pixel. Color display is performed by spectroscopically transmitting any light.

  Generally, a cold cathode fluorescent lamp (CCFL) is used as a light source of a liquid crystal display device. FIG. 6 shows a cross-sectional view of the CCFL in the long axis direction. The CCFL has a structure in which a phosphor 12 is applied to the inner wall of a glass tube 11 and electrodes 13 are provided at both ends of the tube. Further, mercury Hg and a rare gas (argon Ar or neon Ne) are sealed as a discharge medium 14 in the tube.

  The CCFL used for this type of backlight (synonymous with a light source) has a very long and characteristic shape unlike a fluorescent lamp for indoor illumination. In general, fluorescent lamps for indoor lighting have a tube diameter (tube inner diameter) of about 30 mm and a tube length of about 1100 mm. On the other hand, in the CCFL, for example, in the case of a 32-inch liquid crystal display device, the tube diameter (tube inner diameter) is about 4 mm and the tube length is about 720 mm. CCFL is characterized by a very small tube diameter.

  In such a CCFL, lighting is performed by applying a high voltage to the electrodes 13 at both ends. When voltage is applied, electrons emitted from the electrode excite mercury Hg, and ultraviolet light is emitted when the excited mercury Hg returns to the ground state. The phosphor is excited by the ultraviolet rays and emits visible light to the outside of the tube.

  The phosphor 12 provided in the CCFL includes a blue phosphor whose emission color is blue (main emission peak wavelength is about 400 nm to 500 nm) and a green phosphor whose main emission peak wavelength is about 500 nm to 600 nm. And a red phosphor powder having a red color (with a main emission peak wavelength of about 600 nm to 650 nm) are mixed to form a predetermined white chromaticity.

In general, blue phosphor BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , green phosphor LaPO ₄ : Tb ³⁺ , Ce ³⁺ , and red phosphor Y ₂ O ₃ : Eu ³⁺ are used as these three color phosphors. Often. Further, as a blue phosphor, (Ba, Ca, Mg, Sr) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ (commonly called SCA phosphor), and as a green phosphor, BaMgAl ₁₀ O ₁₇ : Eu ²⁺ Mn ²⁺ , YVO ₄ : Eu ³⁺ may be used as a red phosphor.

As a general notation of the phosphor material, the front of “:” indicates the matrix material composition, the back indicates the emission center, and means that some atoms of the matrix material are replaced with the emission center. For example, in the green phosphor LaPO ₄ : Tb ³⁺ , Ce ³⁺ , LaPO ₄ is a base material, and a part of lanthanum La is substituted with terbium Tb, which is the emission center. Cerium Ce is added as a sensitizer that sensitizes the emission of Tb. Therefore, LaPO ₄ : Tb ³⁺ , Ce ³⁺ may be described as (La, Tb, Ce) PO ₄ .

  Visible light emitted from the CCFL (light source 5) passes through optical members such as a diffusion plate 6, a prism sheet 7, and a polarizing plate 8 disposed immediately above the visible light, as shown in FIG. The light enters the facing liquid crystal element 2. Further, in order to improve the utilization efficiency of light from the CCFL, the reflecting plate 4 is disposed immediately below the CCFL, and the light reflected by the reflecting plate is transmitted through the optical member described above and is incident on the liquid crystal element 2.

  On the other hand, the liquid crystal element 2 has a cross-sectional structure shown in FIG. That is, a pair of glass substrates 21 (21A, 21B) facing each other and an alignment film 23 are applied on the inner surface of each substrate, and further, a liquid crystal 24 and a color filter 25 (red 25A, green 25B, blue) are interposed between the substrates. 25C) is a sandwiched structure.

  The glass substrate 21 (21A-21B) is held by a spacer 26. The polarizing plates 22 (22A, 22B) are respectively disposed outside the pair of substrates 21 (21A, 21B). The liquid crystal 24 is uniformly aligned by the alignment film 23 and is driven by applying a voltage to an electrode group (not shown in FIG. 10) formed for each pixel. When a voltage is applied, the liquid crystal rotates according to the electric field generated thereby, and the refractive index of the liquid crystal layer changes to adjust the light transmission amount.

  The color filter 25 (25A, 25B, 25C) splits the white light W from the backlight unit 1 into red light R, green light G, and blue light B for each pixel, and transmits any light.

  In this way, the liquid crystal display device adjusts the amount of light transmitted from the light source provided in the backlight unit for each pixel with the liquid crystal element, and transmits any one of red, green, and blue light for each pixel. Color display is performed by spectrally dividing with a color filter.

  The following is mentioned as a literature regarding the fluorescent substance apply | coated to the lamp | ramp for the purpose of the characteristic improvement of the fluorescent lamp used for the said white light source. However, in the examples shown in these documents, the luminance of the fluorescent lamp cannot be sufficiently improved.

JP 2006-322991 JP 2004-250694 A JP 2002-311429 A JP 2002-056812 A

  In recent years, the market for liquid crystal display devices is mainly expanding as a large-sized liquid crystal television, and further cost reduction and higher image quality are required. In order to solve these requirements, it is necessary to increase the brightness and improve the chromaticity of the CCFL which is a light source.

  In particular, increasing the brightness of CCFLs is an important issue. By solving this problem, it is possible to reduce the cost of a liquid crystal display device. For example, when designing a backlight unit having the same brightness, the number of CCFLs can be reduced as compared with the prior art, and considering that the number of inverters can be reduced at the same time, a great reduction in cost can be realized. Further, by increasing the brightness of the CCFL, it is possible to omit an optical member (for example, a brightness enhancement film) interposed between the CCFL and the liquid crystal element, so that the cost of the liquid crystal display device can be reduced.

  On the other hand, the chromaticity of CCFL is a factor that greatly affects the image quality of a liquid crystal display device, and its improvement is an important issue. In a liquid crystal display device, an amount of light transmitted from a light source is adjusted by a liquid crystal element, and further an image is displayed by performing spectral analysis. Therefore, the chromaticity characteristics of CCFL directly affect the color tone of the liquid crystal display device.

  Therefore, in the present invention, for the purpose of achieving both cost reduction and high image quality of a liquid crystal display device that is increasing in size, it is necessary to improve luminance and chromaticity of a light source typified by CCFL by means described below. Solve these issues.

  In the present invention, the following means are used for the purpose of solving the problems of increasing the luminance of a light source and improving the chromaticity and providing an image display device with high luminance and high image quality.

The object is to provide a fluorescent lamp or an image display device using ultraviolet light emission by discharge, and as a blue phosphor, BaMgAl ₁₀ O ₁₇ : Eu phosphor at least partially, and CIE chromaticity coordinates in light emission of the phosphor This can be solved by a fluorescent lamp or an image display device characterized in that the y value is in the range of 0.053 to 0.065. If the y value of the CIE chromaticity coordinates is in the range of 0.055 to 0.060, more desirable characteristics can be obtained.

As another configuration of the present invention, in a fluorescent lamp or an image display device using ultraviolet light emission by discharge, as a blue phosphor, BaMgAl ₁₀ O ₁₇ : Eu phosphor is included at least partially, and in the phosphor emission spectrum The ratio of the emission intensity at 480 nm to the maximum value of the emission intensity at around 450 nm is in the range of 41 to 48%, which can be solved by a fluorescent lamp or an image display device. Further, if the ratio of the emission intensity at 480 nm to the maximum value of emission intensity at around 450 nm in the phosphor emission spectrum is in the range of 45 to 48%, more desirable characteristics can be obtained.

The fluorescent lamp or the image display device having the above-described characteristics includes at least partly BaMgAl ₁₀ O ₁₇ : Eu phosphor as a blue phosphor, and is heated to 500 ° C. or more in the manufacturing process of the fluorescent lamp. Can be realized by a fluorescent lamp and an image display device characterized by being 1 minute or more and 25 minutes or less. Further, in the manufacturing process of the fluorescent lamp, if the time for heating to 500 ° C. or more is 2 minutes or more and 15 minutes or less, more desirable characteristics can be obtained.

  The effect of the present invention can be made remarkable when the median particle diameter d50 of the phosphor is in the range of 1.0 μm to 10.0 μm.

  In the fluorescent lamp, when the fluorescent lamp is a white light emitting fluorescent lamp having a cold cathode line structure having a fluorescent film containing a red light emitting phosphor, a green light emitting phosphor and a blue light emitting phosphor, the effect can be remarkable. .

  In the present invention, by using the above means, it is possible to achieve both improvement in luminance of the light source and improvement in chromaticity. Moreover, by using such a light source, a high-quality image display device can be obtained in the image display device.

  First, the principle that the present invention provides improvement in luminance and chromaticity will be described.

As a result of examination of the phosphor for the lamp, the luminous efficiency when the BaMgAl ₁₀ O ₁₇ : Eu phosphor is excited with ultraviolet light of 254 nm and the chromaticity value y which is one of the chromaticity indices are shown in FIG. It turned out that it was the relationship.

  Here, the chromaticity value y is an indicator of emission color according to the standard defined as CIE chromaticity coordinates. Here, the phosphor emits ultraviolet light of 254 nm, and the emission from the phosphor is measured by a chromaticity meter. The value measured in was used. The chromaticity value y may be obtained by other methods such as calculating from the emission spectrum using a color matching function.

  In a blue phosphor, the smaller the chromaticity value y, the better the color reproducibility. That is, the direction in which the chromaticity value y decreases is the direction in which the chromaticity is improved. As the emission color of the blue phosphor used for the display, the chromaticity value y is preferably 0.065 or less. More desirably, the color reproducibility is good if it is 0.06 or less.

  For the luminous efficiency, a value obtained by dividing the luminance measured with a luminance meter by the chromaticity value y was used. The luminous efficiency may be obtained by other methods such as a measured value obtained by a light receiving cell provided with a radiometric filter.

  From the relationship shown in FIG. 1, it can be seen that the luminous efficiency is high when the chromaticity value y is 0.053 or more. However, if the chromaticity value y is too large, even if the luminous efficiency is high, the color reproducibility is poor and the image quality as a display is lowered. When the chromaticity value y is in the range of 0.053 to 0.065, a phosphor with high luminous efficiency and good chromaticity can be obtained. The present invention can provide a fluorescent lamp and an image display device having high luminance and good chromaticity by using the phosphor in this range.

Such a change in chromaticity value can be explained by an emission spectrum. FIG. 2 shows an emission spectrum of the BaMgAl ₁₀ O ₁₇ : Eu phosphor. The maximum value of the emission intensity around 450 nm is normalized to 1. When the chromaticity value y is in the range of 0.053 to 0.065, the spectrum changes as shown in FIG. What is characteristic is that the chromaticity value y decreases as the emission intensity at 450 to 530 nm decreases. Here, the light emission intensity at 480 nm is used as an index of chromaticity value change. When the emission intensity at 480 nm is 41 to 48% with respect to the maximum emission intensity around 450 nm, the chromaticity value y is within the range of 0.053 to 0.065.

Such a difference in luminous efficiency and spectrum is attributed to the crystal structure of the phosphor. FIG. 4 shows a main peak (about 2θ = about 33.2 degrees) by X-ray diffraction of the BaMgAl ₁₀ O ₁₇ : Eu phosphor. Here, the X-ray diffraction measurement result using the Kα1 characteristic X-ray of the Cu target is shown. A sample with a chromaticity value y = 0.068, a sample with a chromaticity value y = 0.049, and a sample with a chromaticity value y = 0.059 according to the present invention are shown. It can be seen that the sample having a lower chromaticity value shifts the position of the main peak to a lower angle. From this, it is shown that the change in the emission spectrum as shown in FIG. 2 is accompanied by the change in the crystal structure. It can also be seen that in the sample with the chromaticity value y = 0.049, the intensity of the X-ray diffraction main peak is reduced and the half-value width is expanded. This indicates that the crystallinity is lowered. From this, it can be seen that the decrease in luminous efficiency seen when the chromaticity value y is low as shown in FIG. 1 is due to the decrease in crystallinity.

One method for producing the phosphor within the scope of the present invention shown above is heat treatment of the phosphor. FIG. 3 shows changes in luminous efficiency and chromaticity value y depending on the heating time when BaMgAl ₁₀ O ₁₇ : Eu phosphor is heated in air at a temperature of 500 ° C. or higher. It can be seen that the phosphor having the characteristic range of the present invention can be obtained within a heating time of 1 minute to 30 minutes.

  Such heat treatment is performed simultaneously with the processing necessary for manufacturing in the fluorescent lamp manufacturing process, so that an increase in cost can be avoided.

  Based on the above principle, the effects of the present invention are not limited to the shape of the fluorescent lamp and the excitation method, but are effective. The CCFL lamp described above is an example. For example, it is effective even in the case of a fluorescent lamp having a planar shape, a hot cathode fluorescent lamp (HCFL), or a fluorescent lamp using ultraviolet light by Xe discharge as an excitation source. It is.

  Embodiments in which the present invention is used for a fluorescent tube and a liquid crystal display device will be described below in detail with reference to the drawings.

  An image display device having the configuration of the present invention was produced by the following method, and its characteristics were evaluated.

  The liquid crystal display device according to this embodiment includes a backlight unit 1 and a liquid crystal element 2 as shown in FIG. Further, the backlight unit 1 includes a white light source 5 and a drive circuit 9 (inverter) for lighting the light source 5, a housing 3, a reflection plate 4, a diffusion plate 6, a prism sheet 7, and a polarization reflection plate 8.

  In this example, the CCFL shown in FIG. 6 was used as the white light source. In both the example and the conventional example, a CCFL using a fluorescent film in which red, green, and blue were mixed was prepared. Hereinafter, the production of CCFL and the production of a liquid crystal display device using the CCFL will be described.

The CCFL production procedure is shown below. First, a binder such as alumina and each color phosphor material are mixed in an organic solvent composed of nitrocellulose and butyl acetate called a vehicle. This liquid mixture is called a suspension. For phosphor film preparation, blue phosphor BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , green phosphor LaPO ₄ : Tb ³⁺ , Ce ³⁺ , red phosphor Y ₂ O ₃ : Eu ³⁺ are mixed as phosphors Suspension was used.

  As the particle diameters of all these phosphors, those having a median particle diameter d50 measured with a Coulter meter in the range of 1.0 μm to 10.0 μm were used.

  Next, one side of the glass tube washed beforehand was immersed in this suspension, and it suck | inhaled with the pump from the other side, and the fluorescent substance was apply | coated to the inner wall of the glass tube by pulling up suspension.

  The material of the glass tube is copal glass, and the tube diameter is 3 mm. Then, the glass tube was baked (fired) to fix the phosphor to the inner wall of the tube. Then, an electrode is attached and the one side of a glass tube is sealed. The gas pressure was adjusted by injecting and exhausting a rare gas such as argon Ar or neon Ne from the opposite side of the sealed side. Further, after injecting mercury, the glass tube was sealed. Finally, the glass tube was turned on for a certain period of time to perform an aging process.

  Next, the assembly of the backlight unit will be described with reference to FIG. The plurality of completed CCFLs 5 are arranged in the metal casing 3. In a liquid crystal display device such as a liquid crystal television that requires high brightness, a direct system in which a plurality of CCFLs are arranged in a plane is adopted.

  Between the metal housing 3 and the CCFL 5, a reflector 4 for efficiently using the light emitted from the CCFL toward the housing is disposed. In addition, in order to suppress the luminance in-plane distribution of the liquid crystal display device, a diffusion plate 6 is disposed immediately above the CCFL. Furthermore, a prism sheet 7 and a polarizing reflector 8 are arranged for the purpose of improving the luminance of the liquid crystal display device. An inverter 9 is connected to the CCFL, and the lighting control of the CCFL is performed by driving the inverter. These are collectively referred to as the backlight unit 1.

  Directly above the backlight unit 1, a liquid crystal element 2 having a color filter that adjusts the amount of light transmitted from the backlight (white light source CCFL) and separates light into red, green, and blue for each pixel is disposed.

  A schematic cross-sectional view of the liquid crystal element is as shown in FIG. As the substrate 21, a glass substrate with a normal thickness of 0.5 mm is used. On one substrate 21A, an electrode (not shown in FIG. 10) was formed for each pixel, and a thin film transistor (TFT) for supplying a voltage to these electrodes was formed. On the other substrate 21B, color filters 25 (red 25A, green 25B, blue 25C) were formed for each pixel. An alignment film 23 for aligning liquid crystal molecules was formed on the surfaces of the pair of substrates, and a liquid crystal 24 was sandwiched between the substrates. In addition, polarizing plates 22 (22A and 22B) were disposed outside the substrate.

  Finally, the backlight unit 1 and the liquid crystal element 2 were combined and covered with a housing 10 to obtain a liquid crystal display device.

  According to Example 1, the fluorescent lamp of the present invention using the phosphor within the range shown in FIG. 1 and an image display device using the same were manufactured. This is simultaneously within the range of the emission spectrum shown in FIG.

  There are several methods for producing such a fluorescent lamp according to the present embodiment. As an example, one is a method of forming the fluorescent film of the present embodiment by forming the fluorescent film on the lamp and then performing heat treatment in the range of FIG. As another method, a method using a blue phosphor powder having the characteristics shown in FIGS. 1 and 2 in advance can be mentioned. A blue phosphor having this characteristic can also be produced by phosphor treatment such as heat treatment within the range of FIG. The fluorescent lamp of the present invention can be produced by any of the methods listed above. Moreover, it can produce also by setting it as the fluorescent film which satisfy | fills the requirements of this invention with another method.

  This image display device has improved blue light emission efficiency and blue chromaticity as compared with the conventional image display device. Therefore, white brightness and color reproducibility were also improved.

  From this, it was shown that the present invention can achieve both high brightness of CCFL and improvement of chromaticity. Further, by using such a light source, it is possible to obtain a high-quality image display device that achieves both low cost and high image quality.

  The second embodiment is different from the first embodiment in the type of light source. In Example 1, CCFL was used, but in this example, HCFL (Hot Cathode Fluorescent Lamp, hot cathode tube) shown in FIG. 7 was used. The phosphor used for HCFL is the same as in Example 1.

  As shown in FIG. 7, HCFL has a structure similar to CCFL, and is greatly different in that the metal electrode portion 13 is a filament electrode. When a voltage is applied between both electrodes of the HCFL, thermoelectrons are emitted from the filament, and the thermoelectrons excite mercury and emit ultraviolet rays.

  As a result of measuring the light emission characteristics of the HCFL using the phosphor of the conventional example and Example 2, it was found that the emission efficiency and chromaticity were improved as compared with the conventional example. From this, it was shown that the present invention can achieve both high luminance and chromaticity improvement even in HCFL. In addition, by using such a light source, a high-quality liquid crystal display device having both low cost and high image quality could be obtained.

  The third embodiment is different from the first embodiment in the type of light source. In Example 1, CCFL was used, but in this example, EEFL (External Electrode Fluorescent Lamp, external electrode tube) shown in FIG. 8 was used. The phosphor used for EEFL is the same as in Example 1.

  Production of EEFL differs from CCFL in the formation of electrode parts. In EEFL, after applying a phosphor to a glass tube, one side of the glass tube is sealed and evacuated, then mercury as a discharge medium is introduced and the other side of the glass tube is sealed. Thereafter, a flexible electrode such as a copper tape is disposed outside the glass tube.

  In such an EEFL, since the glass tube itself serves as a capacitor, a ballast capacitor is not required, and multiple lighting driving in which a plurality of lamps 5 are lit by a single inverter 9 is possible. This can be expected to reduce costs because the number of inverters can be greatly reduced compared to CCFL.

  As a result of measuring the light emission characteristics of EEFL using the phosphor of the conventional example and Example 3, it was found that the emission efficiency and chromaticity were improved as compared with the conventional example as in Example 1.

  From this, it was shown that the present invention can achieve both high luminance and chromaticity improvement even in EEFL. In addition, by using such a light source, a high-quality liquid crystal display device having both low cost and high image quality could be obtained.

  The fourth embodiment is different from the first embodiment in the type of light source. In Example 1, CCFL was used, but in this example, the planar light source shown in FIG. 9 was used. The phosphor used for EEFL is the same as in Example 1.

As shown in FIG. 9, the planar light source includes a sealed container 15 (back glass 15A, front glass 15B) provided with a phosphor 12, and an electrode 13 (on the back glass).
13A, 13B). Further, a dielectric 16 is disposed on the electrode. The discharge medium 14 is enclosed in the sealed container. The discharge medium varies depending on the type of the planar light source, but there is a light source using Xe gas and a light source using mercury.

  As a result of measuring the light emission characteristics of the planar light source using the phosphor of the conventional example and Example 4, it was found that the light emission efficiency and chromaticity were improved as compared to the conventional example as in Example 1.

  From this, it was shown that the present invention can achieve both high luminance and chromaticity improvement even in a planar light source. In addition, by using such a light source, a high-quality liquid crystal display device having both low cost and high image quality could be obtained.

It is a figure which shows the relationship between the luminous efficiency of this invention, and chromaticity value y. It is a figure which shows the emission spectrum of this invention. It is a figure which shows the change by the heating time of the luminous efficiency and chromaticity value y of this invention. It is a figure which shows the relationship between the X-ray-diffraction peak of this invention, and chromaticity value y. It is a figure which shows the disassembled perspective view of a liquid crystal display device. It is a figure which shows the outline of the cross-section of a cold cathode tube (CCFL). It is a figure which shows the outline of the cross-section of a hot cathode tube (HCFL). It is a figure which shows the outline of the cross-section of an external electrode tube (EEFL). It is a figure which shows the schematic cross section of a planar light source. It is a figure which shows the outline of the cross-section of a liquid crystal element.

Explanation of symbols

1 ... Backlight unit,
2 ... Liquid crystal element,
3 ... Case (bottom),
4 ... reflector,
5 ... Light source (eg CCFL),
6 ... diffusion plate,
7 ... Prism sheet,
8 ... Polarizing reflector,
9: Inverter,
10: Housing (top),
11 ... Glass tube,
12 ... phosphor,
13 ... electrodes
14 ... discharge medium,
15 ... Sealed container (15A, 15B),
16 ... partition wall,
21, 31 ... Glass substrate,
22, 32 ... Polarizing plate,
23 ... Alignment film,
24 ... Liquid crystal,
25 (25A, 25B, 25C) ... color filters (red, green, blue),
26 ... spacer,
27, 37: Pixel electrodes.

Claims (14)

A fluorescent lamp that uses ultraviolet rays from electric discharge and has a phosphor attached to the inside.
The phosphor BaMgAl ₁₀ O _17: includes a blue phosphor including Eu ^2+, the BaMgAl ₁₀ O _17: main peak of X-ray diffraction of the Eu ²⁺ from 33.18 degrees, in a range of 33.22 ° And a y value of the CIE chromaticity coordinates of the BaMgAl ₁₀ O ₁₇ : Eu ²⁺ is in the range of 0.053 to 0.065.   The fluorescent lamp according to claim 1, wherein the y value of the CIE chromaticity coordinates is in the range of 0.055 to 0.060. The emission spectrum of the BaMgAl ₁₀ O ₁₇ : Eu ²⁺ exhibits a maximum emission intensity around 450 nm, and the emission intensity at 480 nm is 41% to 48% of the emission intensity around 450 nm. Item 2. The fluorescent lamp according to Item 1. The emission spectrum of the BaMgAl ₁₀ O ₁₇ : Eu ²⁺ shows a maximum value of emission intensity around 450 nm, and the emission intensity at 480 nm is 45% to 48% of the emission intensity around 450 nm. Item 2. The fluorescent lamp according to Item 1. A fluorescent lamp that uses ultraviolet rays from electric discharge and has a phosphor attached to the inside.
The phosphor includes a blue phosphor containing BaMgAl ₁₀ O ₁₇ : Eu ^2+, and the BaMgAl ₁₀ O ₁₇ : Eu ²⁺ is heated to 500 ° C. or higher for 1 minute or more and 30 minutes or less. And the y value of the CIE chromaticity coordinates of the BaMgAl ₁₀ O ₁₇ : Eu ²⁺ is in the range of 0.053 to 0.065. The fluorescent lamp according to claim 5, wherein the BaMgAl ₁₀ O ₁₇ : Eu ²⁺ is manufactured through a process in which the time for heating to 500 ° C. or more is 2 minutes or more and 15 minutes or less.   6. The fluorescent lamp according to claim 5, wherein the y value of the CIE chromaticity coordinates is in the range of 0.055 to 0.060. A liquid crystal display device having a liquid crystal element and a backlight unit including a fluorescent lamp on the back,
The fluorescent lamp is a fluorescent lamp that uses ultraviolet rays due to discharge, and has a phosphor attached to the inside.
The fluorescent lamp of the phosphor BaMgAl ₁₀ O _17: includes a blue phosphor including Eu ^2+, the BaMgAl ₁₀ O _17: main peak of X-ray diffraction of Eu ²⁺ is from 33.18 °, 33.22 A liquid crystal display device, wherein the y value of the CIE chromaticity coordinates of BaMgAl ₁₀ O ₁₇ : Eu ²⁺ is in the range of 0.053 to 0.065. 9. The liquid crystal display device according to claim 8, wherein a y value of the CIE chromaticity coordinate of the BaMgAl ₁₀ O ₁₇ : Eu ²⁺ in the fluorescent lamp is in a range of 0.055 to 0.060. The emission spectrum of the BaMgAl ₁₀ O ₁₇ : Eu ²⁺ in the fluorescent lamp shows the maximum value of emission intensity around 450 nm, and the emission intensity at 480 nm is 41% to 48% of the emission intensity around 450 nm. The liquid crystal display device according to claim 8. The emission spectrum of the BaMgAl ₁₀ O ₁₇ : Eu ²⁺ in the fluorescent lamp shows the maximum value of emission intensity around 450 nm, and the emission intensity at 480 nm is 45% to 48% of the emission intensity around 450 nm. The liquid crystal display device according to claim 8. A liquid crystal display device having a liquid crystal element and a backlight unit including a fluorescent lamp on the back,
The fluorescent lamp is a fluorescent lamp that uses ultraviolet rays due to discharge, and has a phosphor attached to the inside.
The phosphor in the fluorescent lamp includes a blue phosphor containing BaMgAl ₁₀ O ₁₇ : Eu ^2+, and the BaMgAl ₁₀ O ₁₇ : Eu ²⁺ is heated to 500 ° C. or more for 1 minute or more and 30 minutes or less. A liquid crystal display device, wherein the y value of the CIE chromaticity coordinates of the BaMgAl ₁₀ O ₁₇ : Eu ²⁺ is in the range of 0.053 to 0.065. 13. The liquid crystal display device according to claim 12, wherein the BaMgAl ₁₀ O ₁₇ : Eu ²⁺ is manufactured through a process in which a time for heating to 500 ° C. or more is 2 minutes or more and 15 minutes or less.   The liquid crystal display device according to claim 12, wherein a y value of the CIE chromaticity coordinates is in a range of 0.055 to 0.060.

Images