JP2009110932A - Illuminating device having fluorescent lamp, displaying device including the same and light diffusion film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illuminating device having a fluorescent lamp, a displaying device including the same and a light diffusion film, capable of improving a color quantity of a high speed animation characteristic. <P>SOLUTION: This illuminating device has the fluorescent lamps 40a-40d. A phosphor layer 10a having blue and red phosphors is formed on an inner surface of a fluorescent lamp tube. A layer 10b of a green phosphor with Eu<SP>2+</SP>or Ce<SP>3+</SP>as the light emitting center, is formed on an outside surface of the fluorescent lamp tube. The green phosphor is excited by the blue light emitted from the blue phosphor. The white light is emitted by a color mixture of the blue light, the red light and the green light. The phosphor layer 10b is formed on a diffusion plate, and may be formed separately from the fluorescent lamp tube. Instead of the phosphor layer 10b, the light diffusion film of forming the green phosphor on a transparent sheet may be formed separately from the fluorescent lamp tube. The green phosphor being 0.2ms or less in 1/10 afterglow time is desirably used. The illuminating device is suitable for the back light of a liquid crystal displaying device for displaying a high speed animation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an illuminating device used for a display device such as a liquid crystal television, and in particular, an illuminating device having a fluorescent lamp that can be suitably used for a display device such as a liquid crystal television that performs high-speed moving image display and the same. The present invention relates to a light diffusion film used for a display device and a lighting device.

  Fluorescent lamps are used as backlights for liquid crystal displays (LCDs) for televisions and PCs. Generally, there are three types of blue light, green light, and red light (3 or more depending on the model). There is also a phosphor that emits light. LCD display colors are mainly fluorescent lamps (Cold Cathode Fluorescent Lamp (CCFL), Hot Cathode Fluorescent Lamp (HCFL), External Electrode Fluorescent Lamp (EEFL), White light emitted from a backlight configured by a flat lamp (FFL: Flat Fluorescent Lamp) is selected by blue, green, and red color filters.

  Conventionally, in order to improve the performance of LCD, various kinds of liquid crystal materials, LED as a light source for backlight, fluorescent lamp and phosphor, driving method, luminance deterioration, color reproducibility, color gamut expansion, video display image quality, etc. For example, with regard to moving image display image quality, improvement using 120 Hz drive, improvement using pseudo-impulse display using black insertion drive method and blinking backlight method using liquid crystal with high-speed response characteristics Methods are known (for example, see Non-Patent Document 1 and Non-Patent Document 2 described below).

  Hereinafter, a conventional technique related to color quality in illumination using a fluorescent lamp will be described.

  Patent Document 1 below entitled “Color Sequential Lighting Device” has the following description.

  FIG. 11 is a schematic view showing one embodiment of a lamp for use in a color sequential lighting device according to Patent Document 1, and a cross-sectional view taken along the line XX. 1 and FIG.

  Referring to FIG. 11, an illumination means such as a discharge tube is generally indicated at 101. The illumination means includes a glass envelope 102 whose inner surface is coated with a powdery blue phosphor 104. The end of the envelope 102 is sealed and includes an electrode 106 for exciting a discharge, such as an ultraviolet discharge, in a gas 108 contained within the glass envelope 102.

  Around the inside of the envelope 102 is an organic phosphor doped with a dye of the plastic material type. During operation of the illumination means, light is generated in the glass envelope 102 by discharge in the gas 108. This causes the blue phosphor powder 104 to emit blue light and this blue light stimulates the fluorescence in the fluorescent plastic material 110. In this case, the fluorescent plastic material 110 is selected to have light characteristics of an appropriate wavelength such as green or red.

  Since the light decay time of the organic fluorescent material 110 is approximately equal to that of the blue phosphor powder 104 (about 0.4 msec), the light emission of both colors does not occur for a long time after the illumination means is turned off. . Furthermore, since the decay times of blue, green and red light can be made substantially equal, the light emitted from the color sequential illuminator is perfectly synchronized with the electrical signal used to control the lamp activation. As a result, undesirable color mixing is reduced. The plastic materials and fluorescent dyes used to produce the organic phosphor 110 can degrade when exposed to relatively high levels of ultraviolet light for a long time, such as those resulting from discharges excited within the envelope 102. However, since the envelope 102 is made of glass and glass is a good absorber of ultraviolet rays, it is not necessary to filter the ultraviolet rays.

  Patent Document 2 below entitled “Variable Color Fluorescent Lamp” has the following description.

  FIG. 12 is a simplified diagram showing an embodiment of a variable color fluorescent lamp according to Patent Document 2, and is FIG. 1 described in Patent Document 2.

  FIG. 12 shows an embodiment according to Patent Document 2. This variable color fluorescent lamp includes an outer tube 201, an inner tube 202, an inner tube support plate 203, and electrodes 204a, 204b, 205a, and 205b.

  The outer tube 201 is made of, for example, glass, which is a light transmissive member, and is formed in a cylindrical shape having an inner diameter of about 30 mm and a length of about 1200 mm, and a phosphor (not shown) having a color temperature of 2800K is formed on the inner surface thereof. It has been applied. Further, both ends of the outer tube 201 are sealed with end plates 206a and 206b, and electrodes 204a and 205a and electrodes 204b and 205b are provided on the end plates 206a and 206b, respectively. The airtight space inside the outer tube 1 is filled with a rare gas of several Torr and mercury vapor which is a metal vapor.

  The inner tube 202 is made of, for example, glass, which is a light transmissive member, like the outer tube 201, and has a spiral structure and is disposed in the outer tube 201. The inner tube 2 is formed by winding a cylindrical body having an outer diameter of 12 mm into a spiral structure having an inner diameter of 5 mm and a length of 150 mm per turn, and the inner surface has chromaticity (0.248, 0.346). A fluorescent material (not shown) having the same color temperature as that of the fluorescent material applied to the outer tube 201 is applied to the outer surface of the blue-green fluorescent material (not shown). A pair of electrodes 205a and 205b are disposed in the vicinity of both ends in the inner tube 202. Further, the inner tube 202 is fixed by an inner tube support plate 203 so that the lower point of the spiral structure abuts the inner surface of the outer tube 201 every turn. The space in the inner tube 202 is configured to form the same airtight space as the space in the outer tube 201.

  In the variable color fluorescent lamp configured in this way, the outer tube 201 and the inner tube 202 are turned on in parallel via a dimming device (not shown), and the dimming control is performed independently of each other. The light color can be obtained. In this embodiment, a result was obtained that the color temperature was 2800K when only the outer tube 201 was turned on, and the color temperature was 6000K when the outer tube 201 and the inner tube 202 were turned on simultaneously.

  In addition, the physical description regarding the afterglow time of fluorescent substance is described in the nonpatent literature 3, for example.

  Furthermore, the phosphor sheet is described in, for example, Patent Document 3, Patent Document 4, Patent Document 5, and Patent Document 6.

JP-A-4-370650 (paragraphs 0009 to 0011, FIGS. 1 and 2) Japanese Patent Laid-Open No. 10-69889 (paragraphs 0013 to 000016, FIG. 1) JP 2007-86797 A (paragraphs 0065 to 0070, paragraphs 0077 to 0078) JP 2006-126109 A (paragraph 0157) JP 2004-161808 (paragraphs 067-0068, FIG. 1) JP 2008-50593 (paragraphs 0006 to 0010, paragraph 0066, paragraphs 0085 to 0086, FIG. 3) “Special feature: Annual report on video information media”, Kurita et al., Journal of the Institute of Image Information Media, Vol.60, No.8, pp.1169 to 1177 (2006) (LCD (page 1169, right column to page 1172, left column)) "High-quality OCB liquid crystal technology", Enomoto et al., Toshiba Review, Vol. 60, No. 7, pp. 42-45 (2005) (Video performance improvement technology (page 44, left column to page 45, left column, Fig. 6) (Fig. 9)) Fluorescent Society, Fluorescent Handbook, Ohmsha, First Edition, pp.101-102 (1987)

  In the following description, a phosphor emitting blue light is abbreviated as “blue phosphor”, a phosphor emitting green light is abbreviated as “green phosphor”, and a phosphor emitting red light is referred to as “red fluorescence”. Abbreviated as “body”.

  A fluorescent lamp is used as the backlight of the LCD. In order to suppress the deterioration of the fluorescent lamp, in particular, the luminance deterioration, the phosphor used in the fluorescent lamp is required to have light resistance, moisture resistance, heat resistance and the like. The organic fluorescent materials described in Patent Document 1 generally have poor light resistance, moisture resistance, heat resistance and the like, and inorganic fluorescent materials are widely used for fluorescent lamps.

  A necessary condition for adapting an LCD having a backlight using a fluorescent lamp to high-speed moving images is that the afterglow time of the phosphor used in the fluorescent lamp is short. Although there is a technique for improving moving image characteristics by blinking a fluorescent lamp at 60 Hz to 120 Hz, even if the fluorescent lamp is blinked at 60 Hz to 120 Hz, if the afterglow time of the phosphor used in the fluorescent lamp is long Since afterglow exists even in a time zone in which the driving of the fluorescent lamp is turned off, the effect of improving the moving image characteristics is reduced.

  That is, when high-speed moving image display is performed by switching on / off the fluorescent lamp at a high frequency (flashing), if the afterglow time of the phosphor used in the fluorescent lamp is long, the afterglow caused by the previous off is not. Since the light emission remains until the next turn-on, there is no point in turning it off. Therefore, it does not make sense for blinking. Therefore, in a liquid crystal display device having a backlight using a fluorescent lamp, in order to improve the color quality of the high-speed moving image characteristics, the phosphor used in the fluorescent lamp, in particular, the green phosphor having the highest specific luminous efficiency. It is necessary that the afterglow time is short.

Widely practically used in which CCFL (Cold Cathode Fluorescent Lamp) blue fluorescent used in _{body, BaMgAl 10 O 17: Eu,} (Sr x, Ba y, Ca z, Mg (1-xyz)) 5 (PO _{4) 3} Cl: is a Eu, their decay time is μsec order. Further, the afterglow time of red phosphors Y ₂ O ₃ : Eu and YVO ₄ : Eu that are put to practical use in CCFL is on the order of msec. As can be seen from the specific luminous efficiency curve, the red light has a low visual sensitivity of about half or less than that of green light. It is hard to stick to. The afterglow time of the red phosphors Y ₂ O ₂ S: Eu and Y ₂ O ₃ : Eu used in the cathode ray tube was on the order of msec, but the afterglow time of the blue and green phosphors was 20 μsec. There is a track record that the video characteristics were good.

The phosphor used in the CCFL must absorb light of mercury at 253.7 nm and emit light efficiently. Various green phosphors used in the CCFL have been proposed, but are LaPO ₄ : Tb and BaMgAl ₁₀ O ₁₇ : Eu, Mn in consideration of lifetime and efficiency. Further, green phosphors that have not been put into practical use are phosphors having Tb ³⁺ and Mn ²⁺ as emission centers. The fluorescence from these phosphors is physically derived from the transition level of the luminescent center metal. Since these emission centers are forbidden transitions, the afterglow time is as long as msec. Both the green phosphor LaPO ₄ : Ce, Tb and BaMgAl ₁₀ O ₁₇ : Eu, Mn are used in fluorescent lamps, and the emission intensity is high, but the afterglow time is as long as msec order.

  In a liquid crystal display device that performs high-speed moving image display, it is required that the fluorescent lamp used for the backlight repeats blinking at a high frequency. Therefore, in order to ensure good color purity of white light, the afterglow time Short phosphors are required to be used for fluorescent lamps.

In the phosphor having Ce ³⁺ and Eu ²⁺ as the emission center, Ce ³⁺ and Eu ²⁺ are permissible transitions, and therefore the afterglow time is on the order of nsec to μsec and is extremely short. There is a green phosphor that emits light with an ultraviolet excitation light of 253.7 nm and has Eu ²⁺ as the emission center, but a phosphor widely used in terms of efficiency and lifetime is not known.

  A phosphor layer can be formed on a substrate by a coating method using a paste-like paint containing phosphor particles. However, as the specific gravity of the phosphor increases and its particle size increases, the phosphor particles are more likely to settle. Therefore, it is difficult to prepare a paint in which the phosphor is uniformly dispersed. For this reason, it is difficult to produce a phosphor layer having a uniform composition and thickness by a coating method, and it is difficult to form a phosphor layer that exhibits uniform light emission without light emission unevenness. Accordingly, even when such a phosphor layer is used as a light diffusion layer and light in each color region of R (red), G (green), and B (blue) is mixed, a uniform light diffusion effect can be obtained. Therefore, it is difficult to emit light having uniform chromaticity and brightness from the light diffusion layer.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an illumination device having a fluorescent lamp and a display using the same, which can improve the color quality of high-speed moving image characteristics. It is providing the light-diffusion film used for an apparatus and an illuminating device.

That is, the present invention includes a fluorescent lamp that emits blue light and red light by a blue phosphor and a red phosphor applied on the inner surface, and is disposed outside the fluorescent lamp, and Eu ²⁺ or Ce ³⁺ is an emission center. A green phosphor layer containing a green phosphor, and green light emitted by exciting the green phosphor with the blue light, and the red light and the blue light are mixed to produce white light. The present invention relates to an illuminating device that emits light.

The present invention also provides a light diffusion layer formed on the sheet-like substrate, comprising a transparent sheet-like substrate, a resin binder, and a green phosphor having an emission center of Eu ²⁺ or Ce ³⁺ A green phosphor that is coated on the inner surface with a blue phosphor and a red phosphor, and is disposed outside a fluorescent lamp that emits blue light and red light. The green phosphor is excited by the blue light and emitted. The present invention relates to a light diffusing film used in an illumination device that emits white light by mixing the red light and the blue light.

  The present invention also relates to a display device having the above illumination device.

According to the illuminating device of the present invention, a fluorescent lamp that emits blue light and red light by the blue phosphor and red phosphor applied on the inner surface, and arranged outside the fluorescent lamp, Eu ²⁺ or Ce ³⁺ A green phosphor layer including a green phosphor having an emission center as a light emission, and green light emitted by exciting the green phosphor with the blue light, and the red light and the blue light are mixed. Since the white light is emitted, even when the fluorescent lamp is blinked at a high frequency, the color purity of the white light emitted from the lighting device is not deteriorated by the afterglow of the green light, and the chromaticity does not change. It is possible to provide a lighting device in which deterioration of moving image quality is suppressed.

According to the light diffusion film of the present invention, it contains a transparent sheet-like base material, a resin binder, and a green phosphor having an emission center of Eu ²⁺ or Ce ³⁺ and is formed on the sheet-like base material. A blue phosphor and a red phosphor are coated on the inner surface and disposed outside the fluorescent lamp that emits blue light and red light, and the green phosphor is excited by the blue light to emit light. The green light, the red light, and the blue light can be suitably used for an illumination device that emits white light, has a substantially uniform light diffusion effect, and has a substantially uniform chromaticity and Light with brightness can be emitted.

  In addition, according to the display device of the present invention, since the illumination device is provided, it is possible to reliably perform flashing of light emission by the backlight On-Off. Therefore, the color quality of moving image characteristics can be improved, and a display device that performs high-speed moving image display, in particular, a liquid crystal display device can be provided.

  In the illuminating device of the present invention, the green phosphor layer is preferably formed on the outer surface of the fluorescent lamp. According to this configuration, by using the fluorescent lamp glass tube that shields ultraviolet rays, the green phosphor is not deteriorated by ultraviolet rays, so that the life of the lighting device can be extended. Further, in the lamp using mercury, there is no problem that mercury is attached to the phosphor and the emission intensity is lowered. The green phosphor is an inorganic phosphor having an emission center wavelength of 500 nm to 570 nm, has a short afterglow time, and is excellent in light resistance and heat resistance.

  The green phosphor layer may be formed on a light diffusing plate disposed outside the fluorescent lamp. According to this configuration, by selecting and using the type of the green phosphor, the color purity of the white light by the lighting device can be made desired.

  The green phosphor layer including the different types of green phosphors may be formed on the light diffusion plate. According to this configuration, the color purity of white light by the lighting device can be changed by using a plurality of phosphors having different chromaticities as the green phosphor.

  The green phosphor layer preferably has a light diffusibility and constitutes a light diffusing plate. According to this configuration, the green phosphor layer has a substantially uniform light diffusing effect, and can emit light having a substantially uniform chromaticity and luminance, and has a fluorescence emission and light diffusing action. It can be set as a light diffusing plate. It is not necessary to provide a light diffusion plate independent of the green phosphor layer, and the configuration of the lighting device can be simplified.

  The green phosphor layer may include different types of the green phosphor. According to this configuration, the green phosphor layer has a substantially uniform light diffusing effect, and can emit light having a substantially uniform chromaticity and luminance, and has a fluorescence emission and light diffusing action. By using a plurality of phosphors having different chromaticities as the green phosphor, the color purity of white light by the illumination device can be changed.

  The green phosphor layer may include light diffusing particles. According to this structure, it can be set as the light diffusing plate which has a more uniform light-diffusion effect.

  The light diffusing particles are preferably resin fine particles. According to this structure, it can be set as the light-diffusion plate which has a more uniform light-diffusion effect more cheaply.

  The 1/10 afterglow time of the green phosphor is preferably 0.2 msec or less. According to this configuration, even when the fluorescent lamp is switched on and off (flashing) at a high frequency, for example, 60 Hz to 120 Hz, the afterglow time of the green phosphor is as short as 0.2 msec or less. The afterglow intensity of the green fluorescence resulting from the previous off applied to the green fluorescence is small, the color purity of the white light emitted from the lighting device is not degraded by the afterglow of the green light, and the chromaticity changes Therefore, it is possible to realize an illumination device that can suppress deterioration of color quality. Therefore, by using such an illuminating device, the color quality of moving image characteristics can be improved, and a liquid crystal display device that performs high-speed moving image display can be realized. The “1/10 afterglow time” indicates the time until the point where the fluorescence emission luminance is reduced to 1/10 with 0 immediately after the excitation is stopped.

  More preferably, the green phosphor has a 1/10 afterglow time of 0.1 msec or less. According to this configuration, since the afterglow time of the green phosphor is further shorter than 0.1 msec or less, the afterglow intensity of the green fluorescence due to the previous off applied to the green fluorescence emitted by the next on is smaller. In addition, it is possible to realize an illumination device that can suppress deterioration in color quality. Therefore, by using such an illuminating device, the color quality of moving image characteristics can be further improved, and a liquid crystal display device that performs high-speed moving image display at a higher frequency can be realized.

  The green phosphor is a rare earth aluminate-based phosphor having a garnet structure, an alkaline earth metal aluminate phosphor, an alkaline earth metal silicate phosphor, an alkaline earth metal silicon oxynitride phosphor, an alkali It is preferable that the earth metal gallium sulfide phosphor be used. According to this configuration, by selecting and using the type of the green phosphor, the color purity of the white light by the lighting device can be made desired.

  As the fluorescent lamp, any one of a cold cathode fluorescent lamp, a hot cathode fluorescent lamp, an external electrode fluorescent lamp, and an electrodeless fluorescent lamp can be used according to the purpose.

  The fluorescent lamp may be a cold cathode fluorescent lamp. According to this configuration, since a cold cathode is used, a long-life and highly reliable lighting device can be realized.

  In the light diffusion film of the present invention, the light diffusion layer may include different types of the green phosphor. According to this configuration, the green phosphor layer has a substantially uniform light diffusing effect, and can emit light having a substantially uniform chromaticity and luminance, and has a fluorescence emission and light diffusing action. By using a plurality of phosphors having different chromaticities as the green phosphor, the color purity of white light by the illumination device can be changed.

  The light diffusing layer may include light diffusing particles. According to this structure, it can be set as the light diffusing plate which has a more uniform light-diffusion effect.

  The light diffusing particles are preferably resin fine particles. According to this structure, it can be set as the light-diffusion plate which has a more uniform light-diffusion effect more cheaply.

  The 1/10 afterglow time of the green phosphor is preferably 0.2 msec or less. According to this configuration, even when the fluorescent lamp is switched on and off (flashing) at a high frequency, for example, 60 Hz to 120 Hz, the afterglow time of the green phosphor is as short as 0.2 msec or less. The afterglow intensity of the green fluorescence resulting from the previous off applied to the green fluorescence is small, the color purity of the white light emitted from the lighting device is not degraded by the afterglow of the green light, and the chromaticity changes Therefore, it is suitable as a light diffusing film used in an illuminating device that can suppress deterioration in color quality. Therefore, by using an illuminating device provided with such a light diffusing film, the color quality of moving image characteristics can be improved, and a liquid crystal display device that performs high-speed moving image display can be realized.

  The display device of the present invention preferably has a liquid crystal panel. A liquid crystal display device having this liquid crystal panel can be suitably used for a television, a display device for a PC, and the like.

  The lighting device may be a backlight. According to this configuration, the display device can be configured to be thin and lightweight.

  Further, it is preferable to have a pixel portion and to synchronize on / off of the pixel portion and blinking of the backlight. According to this configuration, black image data is partially inserted into one frame (the area to be inserted is referred to as “black insertion area”), and the black image display timing is set at a position corresponding to the black insertion area. Since a certain backlight is turned off in synchronization with the movement of the black insertion area, that is, the backlight corresponding to the area other than the black insertion area is turned on, and the backlight at the position corresponding to the black insertion area is turned on. Since the light is turned off, the color quality of the moving image characteristic can be improved, and a display device capable of performing high-speed moving image display can be realized.

The manufacturing method of the illuminating device by this invention has the following characteristics.
(1) A process for producing a fluorescent lamp that emits blue light and red light by coating a blue phosphor and a red phosphor on the inner surface, a binder resin, and a green phosphor having Eu ²⁺ or Ce ³⁺ as the emission center. A step of forming a green phosphor layer using a paint having a viscosity of 4 Pa · s or more, more preferably 5 Pa · s or more and 20 Pa · s or less, wherein the green phosphor layer is the fluorescent lamp. The green light emitted from the green phosphor excited by the blue light and mixed with the red light and the blue light is emitted to emit white light. .

  According to the manufacturing method of the lighting device of the present invention, even when the specific gravity of the green phosphor is large and the particle size thereof is large, the coating material in which the green phosphor hardly settles and the green phosphor is uniformly dispersed is prepared. It is possible to provide a lighting device having the green phosphor layer that can be produced by a coating method and has a uniform composition and thickness, and has uniform emission without any uneven emission. it can. In particular, when the viscosity of the paint is 5 Pa · s or more and 20 Pa · s or less, the dispersion stability of the phosphor particles is excellent, the coating film has a more uniform composition and thickness, and more uniform light emission. The green phosphor layer can be produced by a coating method.

  (2) In said (1), the said coating material is apply | coated to the outer surface of the said fluorescent lamp, and the said green fluorescent substance layer is formed. According to this configuration, it is possible to manufacture an illumination device that enables uniform illumination.

  (3) In the above (1), the paint is applied to a light diffusing plate disposed outside the fluorescent lamp to form the green phosphor layer. According to this configuration, even when the light diffusion plate has a large area, the green phosphor layer having a uniform composition and thickness can be produced by a coating method.

  (4) In the above (3), the paints each containing different types of the green phosphors are sequentially used, and the green phosphor layers each containing the different types of the green phosphors are sequentially formed on the light diffusion plate. The By using a plurality of phosphors having different chromaticities as the green phosphor, the color purity of white light by the illumination device can be changed.

  (5) In the above (1), the coating material is applied to a light-transmitting flat plate to form a light diffusing plate having light diffusing properties. According to this configuration, the green phosphor layer has a substantially uniform light diffusing effect, and can emit light having a substantially uniform chromaticity and luminance, and has a fluorescence emission and light diffusing action. It can be set as a light diffusing plate.

  (6) In the above (5), the paint contains different types of the green phosphors. According to this configuration, the green phosphor layer has a substantially uniform light diffusing effect, and can emit light having a substantially uniform chromaticity and luminance, and has a fluorescence emission and light diffusing action. By using a plurality of phosphors having different chromaticities as the green phosphor, the color purity of white light by the illumination device can be changed.

  (7) In said (5), the said coating material contains the light-diffusion particle different from the said green fluorescent substance. According to this structure, it can be set as the light diffusing plate which has a more uniform light-diffusion effect.

  (8) In the above (7), the light diffusion particles are resin fine particles. According to this structure, it can be set as the light-diffusion plate which has a more uniform light-diffusion effect more cheaply.

  (9) In the above (1), the paint is prepared by dispersing the green phosphor in a solution containing an organic resin. According to this configuration, when adjusting the paint, by adjusting the mixing ratio of the organic resin and the green phosphor, the viscosity of the paint can be in a suitable range according to the type of coating method, The green phosphor layer having a uniform composition and thickness can be produced by a coating method, and an illuminating device having the green phosphor layer exhibiting uniform light emission without light emission unevenness can be provided.

  (10) In the above (9), polyurethane, polyester, urethane acrylate, acrylic monomer or the like is used as the organic resin. According to this configuration, a deformable flexible green phosphor layer can be formed by using the organic resin having flexibility after curing.

  Blue light and red light have low visibility and green light has high visibility, so even if the afterglow time of blue light and red light is long, the brightness of afterglow when the backlight of the liquid crystal display is turned off The impact on is minor. Blue and red have little effect on the brightness of afterglow, but green has high visibility and a large contribution to the afterglow time. Therefore, in the present invention, the brightness of afterglow when the backlight is turned off is greatly increased. In order to reduce this, a green phosphor with a short afterglow time is used.

In the illuminating device using the fluorescent lamp of the present invention, the blue phosphor and the red phosphor are arranged on the outer side of the CCFL by the blue emission emitted from the CCFL coated on the inner surface, and Eu ²⁺ and Ce ³⁺ are emitted from the emission center. A green phosphor having a short afterglow time is excited and emitted, and white light is generated by mixing blue light, red light emitted from the inside of the CCFL, and green light emitted from the outside of the CCFL. For example, a configuration in which a green phosphor is applied to the outer surface of a CCFL glass tube, a configuration in which a green phosphor is applied or kneaded on the surface of a diffusion plate or various optical sheets constituting a backlight, and a green phosphor layer is transparent. It can be formed on a sheet-like substrate, and the green phosphor layer can be configured as a light diffusion plate (having fluorescence emission and light diffusion action).

  A green phosphor layer formed on a flat surface such as a light diffusing plate is a paste paint (coating solution) by mixing phosphor particles in a binder (binder or binder) dissolved or diluted in an organic solvent. Can be applied to a light diffusion plate and dried. In order to increase the emission intensity from the green phosphor layer, it is desirable to increase the packing rate of the phosphor particles in the green phosphor layer and to increase the light transmittance of the green phosphor layer.

  As the binder, for example, ethyl cellulose, ethylene vinyl acetate copolymer, nitrocellulose, polyvinyl acetate, cellulose acetate butyrate, polyvinyl butyral, polyvinyl alcohol, urethane resin, acrylic resin, and the like can be used. Examples of the organic solvent include ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, and halogenated hydrocarbons such as methylene chloride and ethylene chloride.

  The coating material can be applied using a general method such as screen printing, bar coater, roll coater or the like. The thickness of the green phosphor layer can be adjusted depending on the viscosity of the coating material, application conditions, and the like. This viscosity can be appropriately changed depending on the mixing conditions and temperature of the organic solvent, the phosphor particles, and the binder when the coating material is prepared.

For example, SrGa ₂ S ₄ : Eu (average particle diameter 12 μmφ, specific gravity 5.1) is used as the green phosphor, and the green phosphor layer formed on the light diffusion plate has a thickness of 15 μm or more and 40 μm or less, and is green. The volume ratio of the green phosphor and the resin (binder) in the phosphor layer is 5 vol% or more and 20 vol% or less. Despite the large average particle diameter and specific gravity of SrGa ₂ S ₄ : Eu, it is dispersed almost uniformly in the layer, has a substantially uniform thickness, has excellent light transmittance, and adheres to the light diffusion plate. Thus, a green phosphor layer having good impact resistance and ultraviolet resistance can be formed.

  Further, instead of forming the green phosphor layer on the light diffusion plate, the green phosphor layer is formed on a transparent sheet-like substrate, and the green phosphor layer has light diffusibility. The sheet-like substrate can also be used as a light diffusing plate (having fluorescence and light diffusing action).

  In addition, after forming a green phosphor layer on a resin substrate having releasability, the green phosphor layer is peeled off from the resin substrate, and the green phosphor layer is converted into a light diffusion plate having fluorescence emission and light diffusion action It can also be used as In this case, the organic resin used as a binder in which the green phosphor is dispersed is made of a flexible green phosphor layer that can be deformed by using a material that has flexibility after curing. A light diffusing plate having the following can be formed.

  The lighting device of the present invention can be used for a display device such as a liquid crystal television, and can be suitably used for a display device such as a liquid crystal television that performs high-speed moving image display.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.

Embodiment A lighting device according to an embodiment of the present invention includes a fluorescent lamp in which a blue phosphor and a red phosphor are excited by ultraviolet rays, and the phosphor layer having the blue phosphor and the red phosphor is a fluorescent lamp tube. A phosphor layer having a green phosphor having an emission center wavelength of 500 nm to 570 nm with Eu ²⁺ or Ce ³⁺ as the emission center is formed on the outer surface of the fluorescent lamp tube. The green phosphor is excited by the blue light emitted from the blue phosphor, and the white light is emitted from the illumination device by the mixed color of the blue light, the red light, and the green light. The phosphor layer having the green phosphor is not formed on the outer surface of the fluorescent lamp tube, but the phosphor layer having the green phosphor is formed on the light diffusing plate to be separated from the fluorescent lamp tube. You can also

  It is desirable to use a phosphor having a 1/10 afterglow time of 0.2 msec or less as a green phosphor, and an illumination device capable of improving the color quality of high-speed moving image characteristics and a display device using the same can do. This illumination device is suitable as a backlight of a liquid crystal display device that performs high-speed moving image display.

  FIG. 1 is a cross-sectional view illustrating a schematic configuration of a lighting device in which a green phosphor is disposed outside a fluorescent lamp in an embodiment of the present invention, and FIG. 1 (A) is a cold cathode fluorescent lamp (CCFL) 40a. 1B shows the configuration of a hot cathode fluorescent lamp (HCFL) 40b, FIG. 1C shows the configuration of an external electrode fluorescent lamp (EEFL) 40c, and FIG. 1D shows the configuration of an electrodeless fluorescent lamp (internal coil type) 40d. It is sectional drawing shown typically.

  1A to 1D show cross-sectional views of a plane passing through the central axis of the fluorescent lamp and parallel to the tube length direction, and FIG. 1A shows a plane perpendicular to the central axis of the fluorescent lamp. FIG. 1B is a cross-sectional view in a plane perpendicular to the central axis of the fluorescent lamp in FIGS. 1B to 1D, and is the same as the cross-sectional view shown in FIG. Omitted.

  As shown in FIGS. 1 (A) to 1 (D), a phosphor layer (hereinafter referred to as a phosphor layer) in which a mixture of a red phosphor powder and a blue phosphor powder is applied to the inner wall surface of a glass tube 11 constituting a fluorescent lamp. (Abbreviated as “red-blue phosphor layer”) 10 a, and a phosphor layer in which green phosphor powder is applied to the outer wall surface of the glass tube 11 (hereinafter abbreviated as “green phosphor layer”). ) 10b is formed. The glass tube 11 is made of glass that absorbs ultraviolet rays and does not transmit. A blue phosphor layer made of blue phosphor and a red phosphor layer made of red phosphor may be laminated on the inner wall surface of the glass tube 11.

  The green phosphor in the green phosphor layer 10b formed on the outer wall surface of the glass tube 11 is excited by the blue light excited and emitted from the blue phosphor and emits green light. As the fluorescent lamp, those of the types shown in FIGS. 1A to 1D can be used for the lighting device according to the purpose. The fluorescent lamp is controlled to blink at a desired frequency, the excitation of red and blue phosphors by ultraviolet light is controlled, red light and blue light are emitted, and green light is emitted from green phosphors by excitation by blue light. To do. And white light is radiate | emitted from an illuminating device by the mixed color of red light, blue light, and green light.

  In the configuration shown in FIGS. 1A to 1D, the green phosphor layer 10b can be formed by laminating two or more types of green phosphor layers having different chromaticities, and the entire green phosphor layer 10b. The chromaticity point can be changed by the abundance ratio (weight ratio) of green phosphors having different chromaticities. Also, two or more types of green phosphor powders having different chromaticities can be mixed and used, and the chromaticity point can be changed by the mixing ratio (weight ratio).

  In the configuration shown in FIGS. 1A to 1D, for example, the green phosphor-1 in the form of a paste is applied to the outer wall surface of the glass tube 11 and dried to form the green phosphor layer-1. Next, the green phosphor layer 10b can be formed by applying the paste-like green phosphor-2 on the green phosphor layer-1 and drying to form the green phosphor layer-2. it can. Alternatively, green phosphor-1 and green phosphor-2 can be mixed to form a paste, which can be applied to the outer wall surface of glass tube 11 and dried to form green phosphor layer 10b.

  As shown in FIG. 1A, a red-blue phosphor layer 10a is formed on the inner surface of the glass tube 11 of the cold cathode lamp 40a, and Hg is enclosed in the glass tube 11 together with a rare gas such as Ar. ing. The cathode side internal electrode 12a and the anode side internal electrode 12b are provided at both ends inside the glass tube 11, and the filament electrode is not provided.

  In the CCFL 40a, a high voltage is applied between the cathode-side conductor wire 13a and the anode-side conductor wire 13b between the cathode-side internal electrode 12a and the anode-side internal electrode 12b, and electrons emitted from the cathode-side internal electrode 12a due to cold cathode emission. Alternatively, the electrons already present in the glass tube 11 are accelerated, and Ar is ionized by collision between the electrons and Ar to generate Ar ions and electrons. Ar ions are accelerated to the cathode side, collide with the cathode side internal electrode 12a, and emit electrons from the electrode 12a. The emitted secondary electrons are accelerated to the anode side, and Ar ionization occurs again. In this way, avalanche is generated and discharge is started, and stable discharge is maintained.

  The collision between electrons and Hg excites Hg from the ground state to the excited state, and ultraviolet light is emitted when Hg in the excited state returns to the ground state. The ultraviolet rays are applied to the red and blue phosphors in the red-blue phosphor layer 10 a, and both phosphors are excited to generate red and blue fluorescence, which is emitted to the outside of the glass tube 11. The green phosphor in the green phosphor layer 10b applied to the outer surface of the glass tube 11 is excited by the blue fluorescence excited from the blue phosphor to generate green fluorescence. The red and blue fluorescence generated inside the glass tube 11 and the green fluorescence generated outside the glass tube 11 are mixed to generate white light.

  As shown in FIG. 1B, the cathode side internal electrode 12a and the anode side internal electrode 12b in the CCFL 40a of FIG. 1A are replaced with a cathode side filament 19a and an anode side filament 19b. In the HCFL 40b, a current is passed through the cathode side filament 19a to generate thermoelectrons. The thermoelectrons generated from the filament are accelerated to the anode side by the high voltage applied between the cathode side filament 19a and the anode side filament 19b. The accelerated thermoelectrons collide with Ar and Ar is ionized to produce Ar ions and electrons. The emitted secondary electrons are accelerated to the anode side, and Hg is excited by collision of the electrons with Hg to generate ultraviolet rays. In the same way as CCFL 40a, this ultraviolet light excites red and blue phosphors to generate red and blue fluorescence, and blue fluorescence excites green phosphors to generate green fluorescence. Produces white light.

  As shown in FIG. 1 (C), the EEFL 40c is different from CCFL and HCFL, and no electrode is provided inside the glass tube 11, and a cathode-side external electrode 14a and an anode are provided at both ends on the outside of the glass tube 11. A side external electrode 14 b is provided, and a voltage is applied from the outside of the glass tube 11 to generate a discharge inside the glass tube 11. This discharge causes ionization of Ar, and the emitted secondary electrons are accelerated to the anode side, and Hg is excited by collision between the electrons and Hg to generate ultraviolet rays. In the same manner as CCFL 40a and CCFL 40b, this ultraviolet light excites red and blue phosphors to generate red and blue fluorescence, and blue fluorescence excites green phosphors to generate green fluorescence. Mixed color to produce white light.

  As shown in FIG. 1 (D), unlike the CCFL 40a, CCFL 40b, and EEFL 40c, the electrodeless fluorescent lamp 40d does not use an electrode for discharge, and is generated from a coil 15 placed inside or outside the glass tube 11. The high-frequency electromagnetic field thus excited excites Hg enclosed therein to generate ultraviolet rays. In the same manner as CCFL 40a, CCFL 40b, and EEFL 40c, this ultraviolet light excites red and blue phosphors to generate red and blue fluorescence, and blue fluorescence excites green phosphors to generate green fluorescence. Fluorescence is mixed to produce white light.

  Although FIG. 1 (D) shows an inner coil type, a configuration (outer coil type) in which the coil 15 is placed outside the glass tube 11 is also possible.

  As described above, in the configuration shown in FIG. 1A to FIG. 1D, the glass tube 11 constituting the phosphor lamp uses a material that does not transmit ultraviolet rays. The blue phosphor layer 10a is required to be resistant to ultraviolet rays, but the green phosphor layer 10b disposed outside the glass tube 11 is not irradiated with ultraviolet rays, so that no ultraviolet deterioration occurs. In this manner, since the deterioration of the green phosphor having the highest specific visibility is suppressed, it is possible to suppress the deterioration of the color quality of white light.

  As the glass tube 11, one that transmits ultraviolet rays can be used, and both the red-blue phosphor layer 10 a and the green phosphor layer 10 b can be arranged outside the glass tube 11. In this case, a red-blue phosphor layer 10a is formed on the outer wall of the glass tube 11, and then a green phosphor layer 10b is formed on the red-blue phosphor layer 10a.

  When the phosphors used for the red-blue phosphor layer 10a and the green phosphor layer 10b are not deteriorated by ultraviolet rays, the red-blue phosphor layer 10a and the green phosphor layer 10b are formed inside the glass tube 11. can do. In this case, the green phosphor layer 10b is formed on the inner wall of the glass tube 11, and then the red-blue phosphor layer 10a is formed on the green phosphor layer 10b.

  The lighting device described in FIG. 1 can be used for a display device such as a liquid crystal television, and can be particularly suitably used for a display device such as a liquid crystal television that performs high-speed moving image display. Moreover, it cannot be overemphasized that it can be used also for general lightings, such as a ceiling lighting fixture.

  2A and 2B are diagrams illustrating a schematic configuration of a lighting device in which a green phosphor is disposed outside a fluorescent lamp in the embodiment of the present invention, FIG. 2A is a perspective view, and FIG. It is sectional drawing.

  In FIG. 1, the illuminating device including the fluorescent lamp formed by forming the green phosphor layer 10b on the outer wall surface of the glass tube 11 has been described. However, in the configuration of the illuminating device illustrated in FIG. 2, the configuration illustrated in FIG. In this embodiment, the lighting device is composed of the fluorescent lamp 40 having a configuration in which the green phosphor layer 10b is not formed on the outer wall surface of the glass tube 11, and the diffusion layer (diffusion sheet) 23 arranged outside the fluorescent lamp 40. Has been.

  The diffusion layer (diffusion sheet) 23 includes a green phosphor layer 18 formed on the surface of the diffusion plate (light diffusion plate) 16 so as to have substantially the same area as the diffusion plate 16. A plurality of fluorescent lamps 40 are arranged substantially parallel to the short side of the diffusion layer 23, and the fluorescent lamp 40 has substantially the same length as the short side of the diffusion layer 23. As the diffusion plate 16, for example, frosted glass, semi-transparent resin plate, a transparent or semi-transparent plate having a roughened surface with fine irregularities, or a transparent thermoplastic resin with a silicone resin or an acrylic resin A composition obtained by kneading a fine particle such as a plate, or a transparent film such as PET (polyethylene terephthalate) coated with a composition obtained by kneading fine particles in a translucent resin is used.

  The diffusion sheet 23 is prepared, for example, by dissolving ethyl cellulose in terpineol to create a binder, mixing the binder with green phosphor powder to form a paste, and applying this to the diffusion plate 16 with a desired thickness by a printing method. Then, it can be formed by drying. The lamp light LL composed of blue fluorescence and red fluorescence emitted from the fluorescent lamp 40 enters the green phosphor layer 18, and the green phosphor is excited by the blue fluorescence and emits green fluorescence. White light generated by mixing blue fluorescent light, green fluorescent light, and red fluorescent light is diffused and leveled by the diffusing plate 16, and is emitted from the diffusing plate 16 as planar white light WL.

  In the configuration shown in FIG. 2, the lamp light LL from the fluorescent lamp 40 is incident on the green phosphor layer 18 and the diffusion plate 16 in this order, but the lamp light LL is incident on the diffusion plate 16 and the phosphor layer 18 in this order. It can also be set as the structure made.

  As described below, two or more types of green phosphor layers having different chromaticities can be laminated to form a phosphor layer, and the presence of green phosphors having different chromaticities in the entire laminated phosphor layer. The chromaticity point can be changed by the ratio (weight ratio). Also, two or more types of green phosphor powders having different chromaticities can be mixed and used, and the chromaticity point can be changed by the mixing ratio (weight ratio).

  FIG. 3 is a diagram for explaining a schematic configuration of a lighting device in which a plurality of types of green phosphors are arranged outside the fluorescent lamp in the embodiment of the present invention. FIG. 3 (A) is a perspective view, and FIG. B) is a cross-sectional view.

  In the configuration shown in FIG. 2, paste-like green phosphor-1 is applied to the diffusion plate 16 and dried to form green phosphor layer-1 (18a), and then green phosphor layer-1 ( The diffusion layer 23 can be formed by applying the paste-like green phosphor-2 on 18a) and drying to form the green phosphor layer-2 (18b). Although not shown, the green phosphor-1 and the green phosphor-2 can be mixed to form a paste, which can be applied to the diffusion plate 16 and dried to form the diffusion layer 23.

  In the configuration shown in FIG. 3, the lamp light LL from the fluorescent lamp 40 is incident on the green phosphor layers 18b and 18a and the diffusion plate 16 in this order. The lamps LL and the phosphor layers 18a and 18b are in this order. A configuration in which the light LL is incident can also be adopted.

  In the configuration shown in FIGS. 2 and 3, a reflector for reflecting the emitted light from the fluorescent lamp 40 is not shown, but for example, as in the illumination device 2 a as shown in FIGS. 5 and 6 described later. As a simple configuration, it is possible to provide a lighting device having a configuration in which a reflecting plate 22 having a plurality of reflecting surfaces having a concave section is formed below the fluorescent lamp 40 shown in FIGS. The illumination device can be configured in the same manner as the illumination devices 2b and 2c shown in FIGS.

  As described above, in the configuration shown in FIGS. 2 and 3, since the glass tube 11 constituting the phosphor lamp uses a material that does not transmit ultraviolet rays, the red-blue phosphor layer 10a disposed inside the glass tube 11 is used. UV resistance is required, but the green phosphor layer 10b disposed outside the glass tube 11 is not irradiated with UV light and does not deteriorate.

  The lighting device described in FIGS. 2 and 3 can be used for a display device such as a liquid crystal television, and can be particularly preferably used for a display device such as a liquid crystal television that performs high-speed moving image display. Moreover, it cannot be overemphasized that it can be used also for general lightings, such as a ceiling lighting fixture.

  4A and 4B are diagrams illustrating a schematic configuration of a lighting device in which a green phosphor is disposed outside a fluorescent lamp in the embodiment of the present invention, FIG. 4A is a perspective view, and FIG. It is sectional drawing.

  In the configuration of the illumination device shown in FIG. 4, a diffusion layer (light diffusion layer) 8 containing a green phosphor is disposed outside a fluorescent lamp 40 with a diffusion film (diffusion plate) 9 provided on the transparent support 6. In this way, the lighting device is configured.

  In place of the diffusion layer (diffusion sheet) 23 in which the green phosphor layer 18 is formed on the surface of the diffusion plate 16 shown in FIG. 2, in the configuration shown in FIG. 4, the green fluorescence formed on the transparent support plate 6. A diffusion film 9 having a light diffusion layer 8 containing a body is used.

  In the configuration shown in FIG. 4, the lamp light LL from the fluorescent lamp 40 is incident on the light diffusion layer 8 and the transparent support plate 6 in this order, but the lamp light LL is sequentially input on the transparent support plate 6 and the light diffusion layer 8. It can also be set as the structure which injects.

  A plurality of fluorescent lamps 40 are arranged substantially parallel to the short side of the diffusion film 9 containing the green phosphor, and the fluorescent lamp 40 has substantially the same length as the short side of the diffusion layer film 9. As the diffusion layer 8 containing the green phosphor, for example, a transparent or translucent film having a surface with fine irregularities roughened by inorganic fine particles or organic fine particles and a binder is used.

  As the transparent support 6 that can be used for the diffusion film 9 containing the phosphor, a transparent plastic film having a high light transmittance is used. For example, polyester, polycarbonate, polyethylene, polypropylene, triacetylcellulose, polychlorinated Examples thereof include vinyl, acrylic, polystyrene, polyamide, and vinylidene chloride-vinyl chloride copolymer. Of these, a polyester film is preferably used in terms of weather resistance, processability, and the like. Although the thickness of a plastic film is not specifically limited, Generally it is 10 micrometers-500 micrometers, Preferably it is about 20 micrometers-200 micrometers.

  Next, the transparent binder resin, resin particles, and particulate lubricant that constitute the light diffusion layer 8 containing the phosphor will be described.

  As the transparent binder resin, a resin excellent in optical transparency is used. For example, polyester acrylate resin, polyurethane acrylate resin, epoxy acrylate resin, polyester resin, urethane-containing polyester resin, urethane resin, acrylic resin , Polycarbonate resin, epoxy resin, cellulose resin, acetal resin, vinyl resin, polyethylene resin, polystyrene resin, polypropylene resin, polyamide resin, polyimide resin, melamine resin, phenol resin, silicone Thermoplastic resins such as fluororesins and fluororesins, thermosetting resins, ionizing radiation curable resins, and the like.

Next, the resin particles are dispersed and contained in the binder resin in order to impart light diffusibility. Examples of the resin particles include acrylic, styrene, and silicone resin particles, green phosphor particles, red phosphor particles, and silica-based inorganic particles that have Eu ²⁺ or Ce ³⁺ as the emission center.

  Taking into consideration the possibility of scratches on other members that may occur when a layer having a diffusion function comes into contact with other members installed as a part of the display member or scratches on the diffusion layer, fluorescent light is considered. Rather than imparting light diffusibility only with inorganic fine particles typified by the body, it is preferable to design with organic resin particles having excellent flexibility.

  Although the average particle diameter of such resin particles is related to the thickness of the light diffusion layer, the lower limit is 2 μm or more, preferably 4 μm or more, and the upper limit is 40 μm or less, preferably 20 μm or less. Since such particles may be embedded in the light diffusion layer and not contribute to the light diffusibility when the particle size distribution becomes wide, it is preferable that the particles have the same particle size as possible. However, since it is easy for moiré to occur when the particle diameter is a single diameter, it is preferable that particles having several kinds of single diameters are mixed.

  Also, two or more kinds of green phosphor fine particles having different chromaticities can be mixed, and the chromaticity point is changed according to the abundance ratio (weight ratio) of the green phosphors having different chromaticities in the entire diffusion layer containing the phosphor. be able to. Also, two or more types of green phosphor powders having different chromaticities can be mixed and used, and the chromaticity point can be changed by the mixing ratio (weight ratio).

  Further, the content of the particles is 1% by weight or more, preferably 5% by weight or more, and 500% by weight or less, preferably 300% by weight or less, as the upper limit, with respect to the binder resin. By using 20 parts by weight or more, sufficient light diffusibility and the ability to convert light emitted from a fluorescent lamp into white can be combined. Moreover, high transparency can be maintained by setting it as 300 weight part or less. In addition, it is also possible to add another diffusing agent as long as the performance is not impaired.

  In the light diffusing layer in the present invention as described above, a lubricant, a crosslinking agent, a colorant, a pigment, an antistatic agent, a flame retardant, an antibacterial agent, an antifungal agent, and an ultraviolet absorber are within the range not impairing the function of the present invention. Various additives such as a light stabilizer, an antioxidant, a plasticizer, a leveling agent, a pigment dispersant, a flow regulator, and an antifoaming agent can be included.

  The light diffusing sheet of the present invention is prepared by mixing the above-described transparent binder resin, phosphor-containing particles, and additives and diluents added as necessary. The coater, blade coater, spin coater, roll coater, gravure coater, flow coater, spray, screen printing, etc. are applied to at least one surface of the above-mentioned transparent support, dried by heating, and heated as necessary. A light diffusion layer can be formed by curing with ionizing radiation.

  As a method of irradiating ionizing radiation, an electron beam emitted from an electron beam accelerator that irradiates ultraviolet rays in a wavelength region of 400 nm or less emitted from an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a metal halide lamp, etc. This can be done by irradiation.

  The thickness of the light diffusion layer as described above is not particularly limited. However, when the thickness is provided by the coating method, the thickness is set to 2 μm to 50 μm, preferably 4 μm to 25 μm.

  As described above, according to the present invention, by providing a light diffusion layer composed of a transparent binder resin, particles containing phosphors, and various additives on at least one surface of a transparent support, Light diffused white light can be obtained in a state where light emitted from the lamp is transmitted.

  The lighting device described in FIG. 4 can be used for a display device such as a liquid crystal television, and can be particularly suitably used for a display device such as a liquid crystal television that performs high-speed moving image display. Moreover, it cannot be overemphasized that it can be used also for general lightings, such as a ceiling lighting fixture.

  FIG. 5 is a cross-sectional view illustrating a schematic configuration of a liquid crystal display device 1a using a direct backlight according to an embodiment of the present invention.

As shown in FIG. 5, the liquid crystal display device 1 a includes a liquid crystal panel 3 and a lighting device 2 a located behind the liquid crystal panel 3 (opposite to the image viewing side). An illuminating device 2a is arranged as a backlight immediately below the back side. That is, the liquid crystal display device 1a is of a transmissive type, by using the white light WL from the illuminating device 2a, the display surface of the liquid crystal panel 2, red display light LO _r, green display light LO _g, blue display and it is configured to emit display light LO consisting of light LO _b.

  In the configuration of the illumination device 2a shown in FIG. 5, a plurality of fluorescent lamps (CCFL) 40 having a configuration in which the green phosphor layer 10b formed on the outer surface of the glass tube 11 is not formed in the CCFL shown in FIG. Between the prism sheet 24 and the fluorescent lamp 40, a diffusion layer 23 composed of a diffusion plate 16 having a green phosphor layer 18 formed on the surface thereof is disposed.

  In the configuration shown in FIG. 5, the diffusion layer 23 may be disposed between the prism sheet 24 and the diffusion sheet 25 and the diffusion sheet 25 may not be disposed.

  In the illuminating device 2a shown in FIG. 5, a plurality of fluorescent lamps 40 are arranged substantially parallel to one side direction of the diffusion layer 23 (side perpendicular to the paper surface in which FIG. 5 is illustrated). 23 is a long fluorescent lamp having substantially the same length as the length in the one side direction. This long fluorescent lamp can also be configured by arranging a plurality of short fluorescent lamps close to each other in the one-side direction.

  In the illumination device 2a, a plurality of cold cathode fluorescent lamps (CCFL) 40 (four in the example shown in FIG. 5) are arranged in parallel as light sources. In addition, a reflector 22 is provided around the cold cathode fluorescent lamps 40 except for the liquid crystal panel 3 side. On the liquid crystal panel 3 side of the plurality of cold cathode fluorescent lamps 40, a diffusion sheet 23 and a prism sheet 24 are provided in this order from the cold cathode fluorescent lamp 40 side. A mixture of lamp light LL composed of red and blue fluorescence excited by ultraviolet rays from the red-blue phosphor layer 10a on the inner wall of the cold cathode fluorescent lamp 40 and green fluorescence excited from the green phosphor layer 18 by blue fluorescence. As a result, white light WL is generated.

  In the configuration shown in FIG. 5, the cold cathode fluorescent lamp 40 may be replaced with the HFCL shown in FIG. 1B, the EEFL shown in FIG. 1C, and the electrodeless tendency lamp shown in FIG. Good.

  The reflection plate 22 is for reflecting the lamp light LL emitted from the cold cathode fluorescent lamp 40 toward the liquid crystal panel 3 side. The reflecting plate 22 is formed with a plurality of concave reflecting surfaces having a circular cross section (for example, a semicircular shape), a parabolic shape, a parabolic shape, etc., and the reflecting surface is made of a material such as Al having a high reflectance of the lamp light LL. It is formed with. The reflector 22 enables the lamp light LL emitted from the cold cathode fluorescent lamp 40 to be used efficiently.

  The diffusion sheets 23 and 25 are for diffusing the white light WL toward the liquid crystal panel 3 to reduce uneven brightness. The prism sheet 24 is for directing the direction of the white light WL.

  The liquid crystal panel 3 has a laminated structure having a multilayer film between a pair of glass substrates 32A and 32B (the glass substrate 32A on the illumination device 2a side and the glass substrate 32B on the observation side). Specifically, the multilayer film is disposed in order from the lighting device 2a side in correspondence with each pixel, the transparent pixel electrode 33 disposed in each pixel, the liquid crystal layer 34, the transparent electrode 35 common to each pixel, and each pixel. The color filter 36 and a black matrix 37 formed between the color filters 36 are configured. Further, polarizing plates 31A and 31B are formed on the surfaces of the glass substrates 31A and 32A opposite to the liquid crystal layer 34, respectively.

  The polarizing plates 31A and 31B are a kind of optical shutter, and allow only light (polarized light) in a certain vibration direction to pass therethrough. The polarizing plates 31A and 31B are arranged so that their polarization axes are different from each other by 90 degrees, and the white light WL from the illumination device 2a is transmitted or blocked through the liquid crystal layer.

  The glass substrates 32A and 32B are generally transparent substrates that are transparent to visible light. Therefore, as long as it is transparent with respect to visible light, it is not limited to a glass substrate, and a transparent resin substrate can also be used. Note that a driving circuit (not shown) having a TFT (Thin Film Transistor) as a driving element electrically connected to the transparent pixel electrode 33, wiring, and the like is formed on the glass substrate 31A.

  The transparent pixel electrode 33 is made of, for example, ITO (Indium Tin Oxide) and functions as a pixel electrode of each pixel. The transparent electrode 35 is also made of, for example, ITO and functions as a common counter electrode.

  The liquid crystal layer 34 is composed of, for example, a liquid crystal such as a TN (Twisted Nematic) mode or an STN (Super Twisted Nematic) mode. It is for transmitting or blocking by the pixel.

  The black matrix 37 is disposed between the color filters 36 to block the white light WL from the irradiation device 2 and prevent it from being emitted to the observation side of the liquid crystal panel 3.

  The color filter 36 is for separating the white light WL from the illumination device 2a into three primary colors of red (R), green (G), and blue (B). It is composed of a red color filter that selectively transmits light in the region, a green color filter that selectively transmits light in the green wavelength region, and a green color filter that selectively transmits light in the blue wavelength region. .

  In the liquid crystal display device of the present embodiment, the lamp light LL from the cold cathode fluorescent lamp 40 having the inner surface coated with red and blue phosphors is emitted to the green phosphor layer 18 by the reflector 22. The green fluorescence excited from the green phosphor layer 18 by the blue fluorescence contained in the lamp light LL is mixed with the red and blue fluorescence contained in the lamp light LL and emitted to the diffuser plate 16 so that the green fluorescence White light WL is generated by a mixture of fluorescence, red, and blue fluorescence. The unevenness of the brightness of the white light WL is reduced by the diffusion sheet 23, and the direction of the white light WL is directed by the prism sheet 24.

The white light WL incident on the liquid crystal panel 3 is modulated by a voltage applied between each transparent pixel electrode 33 and the transparent electrode 35 based on the video signal, and is color-separated by the color filter 36 corresponding to each color. . Therefore, the display light LO composed of the red display light LO _r , the green display light LO _g , and the blue display light LO _b is emitted to the display surface on the observation side of the liquid crystal panel 2, and color video display is performed.

  In the display device, on / off of a voltage applied to the transparent pixel electrode 33 constituting the pixel portion is controlled by a drive element (TFT) electrically connected to the transparent pixel electrode 33. The on / off of the voltage applied to the transparent pixel electrode 33 is synchronized with the blinking of the fluorescent lamp 40 constituting the liquid crystal display device 1a. The fluorescent lamp 40 may be composed of a plurality of short fluorescent lamps instead of the long fluorescent lamp as described above, and the voltage applied to the transparent pixel electrode 33 can be turned on and off. It can also be set as the structure which synchronizes blinking of a fluorescent lamp.

  In this liquid crystal display device, a video display period for turning on the driving element and a black display period for inserting black image data for turning off the driving element are provided for each frame, and a single black image data is provided in a part of one frame. Alternatively, a backlight at a position corresponding to a black insertion region (a region where black image data is inserted is referred to as a “black insertion region”) is inserted into a plurality of scanning lines and is synchronized with the black image display timing. Then, it is turned off in synchronization with the movement of the black insertion area. When synchronizing the blinking of the short fluorescent lamp, black image data can be inserted into a part of one or a plurality of scanning lines.

  That is, the backlight corresponding to the area other than the black insertion area is turned on, and the backlight at the position corresponding to the black insertion area is turned off. By realizing pseudo impulse display by such control, moving image visibility can be improved in high-speed moving image display, and color quality of moving image characteristics can be improved.

  In the configuration shown in FIG. 5, the lamp light LL from the fluorescent lamp 40 is incident on the green phosphor layer 18 and the diffusion plate 16 in this order, but the lamp light LL is incident on the diffusion plate 6 and the green phosphor layer 18 in this order. It can also be set as the structure which injects.

  In the configuration shown in FIG. 5, the direct type backlight in which the illuminating device 2 a is disposed on the back surface of the liquid crystal panel 3 has been described. However, a light guide plate is disposed on the back surface of the liquid crystal panel 3 and It is also possible to adopt an edge light type (side light type, light guide plate type) backlight configuration in which a plurality of fluorescent lamps are arranged at the edge portion.

  FIG. 6 is a cross-sectional view illustrating a schematic configuration of a liquid crystal display device 1 a ′ using a direct type backlight in the embodiment of the present invention.

  In place of the diffusion layer (diffusion sheet) 23 in which the green phosphor layer 18 is formed on the surface of the diffusion plate 16 shown in FIG. 5, the green fluorescence formed on the transparent support plate 6 is used in the configuration shown in FIG. 6. A diffusion film 9 having a light diffusion layer 8 containing a body is used.

As shown in FIG. 6, the liquid crystal display device 1 a ′ includes a liquid crystal panel 3 and an illumination device 2 a located behind the liquid crystal panel 3 (opposite to the image viewing side). An illumination device 2a is disposed as a backlight immediately below the back side of the lamp. That is, the liquid crystal display device 1a ′ is of a transmissive type, and the red display light LO _r , the green display light LO _{g, the} blue color is displayed on the display surface of the liquid crystal panel 2 using the white light WL from the illumination device 2a. and it is configured to emit display light LO consisting of display light LO _b.

  In the configuration of the illumination device 2 a shown in FIG. 6, a plurality of fluorescent lamps (CCFL) 40 are used, and a diffusion layer 8 containing a green phosphor is formed on the transparent support substrate 6 between the prism sheet 24 and the fluorescent lamp 40. The diffused film 9 is disposed. The structure of the diffusion film 9 is the same as that shown in FIG.

  In the illuminating device 2a shown in FIG. 6, a plurality of fluorescent lamps 40 are arranged substantially parallel to one side direction of the diffusing layer 8 containing the phosphor (side perpendicular to the paper surface on which FIG. 6 is illustrated). Reference numeral 40 denotes a long fluorescent lamp having substantially the same length as the length of the diffusion layer 8 containing a phosphor in the one-side direction. This long fluorescent lamp can also be configured by arranging a plurality of short fluorescent lamps close to each other in the one-side direction.

  In the illumination device 2a, a plurality of cold cathode fluorescent lamps (CCFLs) 40 (four in the example shown in FIG. 6) are arranged in parallel as light sources. In addition, a reflector 22 is provided around the cold cathode fluorescent lamps 40 except for the liquid crystal panel 3 side. On the liquid crystal panel 3 side of the plurality of cold cathode fluorescent lamps 40, a prism sheet 24 and a diffusion film 9 are provided in this order from the cold cathode fluorescent lamp 40 side. Lamp light LL composed of red and blue fluorescence excited by ultraviolet rays from the red-blue phosphor layer 10a on the inner wall of the cold cathode fluorescent lamp 40, and green excited from the diffusion layer 8 containing green phosphor by blue fluorescence. The white light WL is generated by the mixed color of the fluorescence.

  In the configuration shown in FIG. 6, the cold cathode fluorescent lamp 40 may be replaced with HFCL, EEFL, or an electrodeless tendency lamp.

  The reflection plate 22 is for reflecting the lamp light LL emitted from the cold cathode fluorescent lamp 40 toward the liquid crystal panel 3 side. The reflecting plate 22 is formed with a plurality of concave reflecting surfaces having a circular cross section (for example, a semicircular shape), a parabolic shape, a parabolic shape, etc., and the reflecting surface is made of a material such as Al having a high reflectance of the lamp light LL. It is formed with. The reflector 22 enables the lamp light LL emitted from the cold cathode fluorescent lamp 40 to be used efficiently.

  The diffusion film (sheet) 9 is for diffusing white light toward the liquid crystal panel 3 to reduce uneven brightness. The prism sheet 24 is for directing the light direction of the cold cathode fluorescent lamp 40 shell.

  The liquid crystal panel 3 has a laminated structure having a multilayer film between a pair of glass substrates 32A and 32B (the glass substrate 32A on the illumination device 2a side and the glass substrate 32B on the observation side). Specifically, the multilayer film is disposed in order from the lighting device 2a side in correspondence with each pixel, the transparent pixel electrode 33 disposed in each pixel, the liquid crystal layer 34, the transparent electrode 35 common to each pixel, and each pixel. The color filter 36 and a black matrix 37 formed between the color filters 36 are configured. Further, polarizing plates 31A and 31B are formed on the surfaces of the glass substrates 31A and 32A opposite to the liquid crystal layer 34, respectively.

  The polarizing plates 31A and 31B are a kind of optical shutter, and allow only light (polarized light) in a certain vibration direction to pass therethrough. The polarizing plates 31A and 31B are arranged so that their polarization axes are different from each other by 90 degrees, and the white light WL from the illumination device 2a is transmitted or blocked through the liquid crystal layer.

  The glass substrates 32A and 32B are generally transparent substrates that are transparent to visible light. Therefore, as long as it is transparent with respect to visible light, it is not limited to a glass substrate, and a transparent resin substrate can also be used. Note that a driving circuit (not shown) having a TFT (Thin Film Transistor) as a driving element electrically connected to the transparent pixel electrode 33, wiring, and the like is formed on the glass substrate 31A.

  The transparent pixel electrode 33 is made of, for example, ITO (Indium Tin Oxide) and functions as a pixel electrode of each pixel. The transparent electrode 35 is also made of, for example, ITO and functions as a common counter electrode.

  The liquid crystal layer 34 is composed of, for example, a liquid crystal such as a TN (Twisted Nematic) mode or an STN (Super Twisted Nematic) mode. It is for transmitting or blocking by the pixel.

  The black matrix 37 is disposed between the color filters 36, and blocks the white light WL from the irradiation device 2a so as not to be emitted to the observation side of the liquid crystal panel 3.

  The color filter 36 is for separating the white light WL from the illumination device 2a into three primary colors of red (R), green (G), and blue (B). It is composed of a red color filter that selectively transmits light in the region, a green color filter that selectively transmits light in the green wavelength region, and a green color filter that selectively transmits light in the blue wavelength region. .

  In the liquid crystal display device of the present embodiment, the lamp light LL from the cold cathode fluorescent lamp 40 having the inner surface coated with red and blue phosphors is reflected by the reflecting plate 22, and the direction thereof is directed by the prism sheet 24. The light is emitted to the diffusion layer 8 containing the green phosphor. The green fluorescence excited from the green phosphor contained in the diffusion layer 8 by the blue fluorescence contained in the lamp light LL is mixed with the red and blue fluorescence contained in the lamp light LL, and unevenness in brightness is reduced. White light WL is generated.

The white light WL incident on the liquid crystal panel 3 is modulated by a voltage applied between each transparent pixel electrode 33 and the transparent electrode 35 based on the video signal, and is color-separated by the color filter 36 corresponding to each color. . Therefore, the display light LO composed of the red display light LO _r , the green display light LO _g , and the blue display light LO _b is emitted to the display surface on the observation side of the liquid crystal panel 2, and color video display is performed.

  In the display device, on / off of a voltage applied to the transparent pixel electrode 33 constituting the pixel portion is controlled by a drive element (TFT) electrically connected to the transparent pixel electrode 33. The on / off state of the voltage applied to the transparent pixel electrode 33 is synchronized with the blinking of the fluorescent lamp 40 constituting the liquid crystal display device 1a '. The fluorescent lamp 40 may be composed of a plurality of short fluorescent lamps instead of the long fluorescent lamp as described above, and the voltage applied to the transparent pixel electrode 33 can be turned on and off. It can also be set as the structure which synchronizes blinking of a fluorescent lamp.

  In this liquid crystal display device, a video display period for turning on the driving element and a black display period for inserting black image data for turning off the driving element are provided for each frame, and a single black image data is provided in a part of one frame. Alternatively, a backlight at a position corresponding to a black insertion region (a region where black image data is inserted is referred to as a “black insertion region”) is inserted into a plurality of scanning lines and is synchronized with the black image display timing. Then, it is turned off in synchronization with the movement of the black insertion area. When synchronizing the blinking of the short fluorescent lamp, black image data can be inserted into a part of one or a plurality of scanning lines.

  That is, the backlight corresponding to the area other than the black insertion area is turned on, and the backlight at the position corresponding to the black insertion area is turned off. By realizing pseudo impulse display by such control, moving image visibility can be improved in high-speed moving image display, and color quality of moving image characteristics can be improved.

  In the configuration shown in FIG. 6, the lamp light LL from the fluorescent lamp 40 is incident on the light diffusion layer 8 and the transparent support plate 6 in this order, but the lamp light LL is sequentially input on the transparent support plate 6 and the light diffusion layer 8. It can also be set as the structure which injects.

  In the configuration illustrated in FIG. 6, the direct type backlight in which the illumination device 2 a is disposed on the back surface of the liquid crystal panel 3 has been described. However, a light guide plate is disposed on the back surface of the liquid crystal panel 3 and It is also possible to adopt an edge light type (side light type, light guide plate type) backlight configuration in which a plurality of fluorescent lamps are arranged at the edge portion.

  7 and 8 are cross-sectional views illustrating the schematic configuration of the liquid crystal display devices 1b and 1c using the side edge type backlight in the embodiment of the present invention.

  The configuration of the liquid crystal display device 1a shown in FIG. 5 in which the illuminating device 2a is arranged directly under the back side of the liquid crystal display panel 3 is changed, and as shown in FIG. A liquid crystal display device 1b using a side edge (side light) type backlight in which the cold cathode fluorescent tube 40 is disposed as a linear light source can be used. White light WL from the fluorescent lamp 40 and the diffusion layers 23 (16, 18) is converted into planar light via the light guide plate 26 and irradiated from behind the liquid crystal panel 3. Hereinafter, a description will be given focusing on differences from the liquid crystal display device 1a shown in FIG.

  In the configuration of the lighting device 2b shown in FIG. 7, a fluorescent lamp (CCFL) 40 having a configuration in which the green phosphor layer 10b formed on the outer surface of the glass tube 11 is not formed in the CCFL shown in FIG. A diffusion layer 23 composed of a diffusion plate 16 having a green phosphor layer 18 formed on the surface is disposed between the light guide plate 26 and the fluorescent lamp 40, and white light WL transmitted through the diffusion layer 23 is applied to the light guide plate 26. It has the structure which injects.

  A mixture of lamp light LL composed of red and blue fluorescence excited by ultraviolet rays from the red-blue phosphor layer 10a on the inner wall of the cold cathode fluorescent lamp 40 and green fluorescence excited from the green phosphor layer 18 by blue fluorescence. As a result, white light WL is generated.

  Further, as shown in FIG. 8, in the configuration shown in FIG. 7, the green phosphor layer 18 is arranged between the prism sheet 24 and the diffusion sheet 25, that is, instead of the diffusion sheet 25 shown in FIG. 23 (diffusion plate 16, green phosphor layer 18) may be arranged. In this case, diffusion layer 23 (16, 18) and light guide plate 26 shown in FIG. 7 are replaced with light guide plate 26a.

  Further, in the configuration shown in FIG. 8, the green phosphor layer 18 is formed between the prism sheet 24 and the light guide plate 26a by forming the green phosphor layer 18 below the prism sheet 24 or above the light guide plate 26a. It can also be set as the structure arrange | positioned.

  In the configuration shown in FIGS. 7 and 8, the lamp light LL from the fluorescent lamp 40 is incident on the green phosphor layer 18 and the diffusion plate 16 in this order. A configuration in which the light LL is incident can also be adopted.

  FIG. 9 is a cross-sectional view illustrating a schematic configuration of a liquid crystal display device 1c ′ using a side-edge type backlight in the embodiment of the present invention.

  The configuration of the liquid crystal display device 1a ′ shown in FIG. 6 in which the illuminating device 2a is arranged directly under the back side of the liquid crystal display panel 3 is changed, and as shown in FIG. A liquid crystal display device 1c ′ using a side edge (side light) type backlight in which the cold cathode fluorescent tube 40 is arranged as a linear light source can be used.

  The lamp light LL from the cold cathode fluorescent lamp 40 is reflected by the reflecting plate 22, converted into planar light through the light guide plate 26a, directed in the direction by the prism sheet 24, and a diffusion layer containing a green phosphor. 8 is emitted. The green fluorescence excited from the green phosphor contained in the diffusion layer 8 by the blue fluorescence contained in the lamp light LL is mixed with the red and blue fluorescence contained in the lamp light LL, and unevenness in brightness is reduced. White light WL is generated.

  White light WL from the diffusion film 9 in which the diffusion layer 8 including the green phosphor is formed on the transparent support substrate 6 is irradiated from behind the liquid crystal panel 3. The structure of the diffusion film 9 is the same as that shown in FIG.

  In the configuration shown in FIG. 9, the diffusing film 9 may be arranged between the prism sheet 24 and the light guide plate 26a.

  In the configuration shown in FIG. 9, the lamp light LL from the fluorescent lamp 40 is incident on the light diffusion layer 8 and the transparent support plate 6 in this order, but the lamp light LL is sequentially input on the transparent support plate 6 and the light diffusion layer 8. It can also be set as the structure which injects.

  FIG. 10 is a cross-sectional view illustrating a schematic configuration of a lighting device in which a green phosphor is arranged outside a fluorescent lamp in an embodiment of the present invention, and FIG. 10A is a glass tube of a green phosphor layer ( FIG. 10B is a diagram for explaining the protection by the transparent coating film of the green phosphor layer. In FIG. 10, only the glass tube 11, the red-blue phosphor layer 10a, and the green phosphor layer 10b are shown among the components shown in FIG. 1 of the fluorescent lamp, and other components are omitted.

  When forming the phosphor layer on the outer surface of the glass tube of the fluorescent lamp, as shown in FIG. 10A, the green phosphor layer 10b formed on the outer surface of the glass tube 11 is replaced with a glass tube (outer tube) 21a. Or a transparent coating film with a low moisture-permeable resin film or glass film on the green phosphor layer 10b formed on the outer surface of the glass tube 11, as shown in FIG. With the configuration in which 21b is formed, the moisture resistance and the like of the green phosphor layer 10b can be improved.

  Needless to say, the configuration shown in FIG. 10 can also be adopted when a blue phosphor layer and / or a red phosphor layer is formed on the outer surface of the glass tube 11 in addition to the green phosphor layer 10b. The fluorescent lamp may be any of CCFL, HCFL, EEFL, and electrodeless fluorescent lamp.

Example (1)
The illumination device comprising the phosphor layer 23 and the fluorescent lamp 40 shown in FIG. 2 is configured, and the afterglow time of the green phosphor is set to 0 immediately after the excitation of the fluorescent lamp is stopped, and the luminance of the green fluorescence is 1/10. The time until the point of decrease was evaluated as 1/10 afterglow time. The measurement of the afterglow time of the green phosphor layer formed on the diffusion plate is performed by measuring the intensity of green fluorescence after stopping the AC power supply of the fluorescent lamp through a green color filter that selectively transmits light in the green wavelength region. This was done by monitoring with a pin diode and observing the decay of green fluorescence with an oscilloscope.

Example 1: Illumination device in which a diffuser plate on which a green phosphor (SrGa ₂ S ₄ : Eu) layer is formed is arranged outside the CCFL A binder is prepared by dissolving 6 g of ethylcellulose in 300 mL of terpineol, and 20 mL of this binder is prepared. On the other hand, green phosphor SrGa ₂ S ₄ : Eu, 5.0 g was mixed to form a paste, which was applied to the diffusion plate 16 by a printing method.

The diffusion plate, and a blue phosphor on the inner wall _{(Sr x, Ba y, Ca} z, Mg (1-xyz)) 5 (PO 4) 3 Cl: Eu, red phosphor Y ₂ 0 _3: Eu is applied The lighting device was constituted by CCFL and used as the backlight of the liquid crystal panel. When is lit attaching the backlight to the liquid crystal panel, so that the white chromaticity point is near (0.300,0.300), a blue phosphor _{(Sr x, Ba y, Ca} z, Mg (1- The weight ratio of _xyz) ) ₅ (PO ₄ ) ₃ Cl: Eu and red phosphor Y ₂ O ₃ : Eu was searched by trial and error, and a mixture of blue phosphor and red phosphor was applied to CCFL. The exploratory test was conducted using a 32-inch LCD TV.

CCFL coated with a mixture of a blue phosphor and a red phosphor with a weight ratio (blue phosphor: red phosphor) = 73: 27 obtained as a result of the search test, and a green phosphor (SrGa ₂ S ₄ : The illuminating device was constituted by a diffusion plate coated with Eu), and this was attached to a liquid crystal panel as a backlight. As a result, the white chromaticity was (0.3024, 0.3077). As a result of taking out this backlight and evaluating the afterglow characteristics of the green phosphor, the 1/10 afterglow time of the green phosphor (SrGa ₂ S ₄ : Eu) was about 0.2 msec.

Example 2: Illuminating device in which a diffuser plate on which a green phosphor ((Sr, Ba, Ca, Mg) ₂ SiO ₄ : Eu) layer is formed is disposed outside the CCFL. In Example 1, the green phosphor (SrGa (Sr: Ba, Ca, Mg) ₂ SiO ₄ : Eu is used instead of ₂ S ₄ : Eu, and 1/10 of the green phosphor (Sr, Ba, Ca, Mg) ₂ SiO ₄ : Eu remains Light time was evaluated.

In the same manner as in Example 1, the green phosphor (Sr, Ba, Ca, Mg ) 2 SiO 4: applying the Eu on the diffusion plate 16, the diffusion plate, and a blue phosphor on the inner wall (Sr _x, Ba _{y , Ca z, Mg (1-} xyz)) 5 (PO 4) 3 Cl: Eu, red phosphor Y ₂ 0 _3: by Eu is applied CCFL, the backlight of this constitutes the illumination device includes a liquid crystal panel It was. The 1/10 afterglow time of the green phosphor (Sr, Ba, Ca, Mg) ₂ SiO ₄ : Eu in this backlight was also about 0.2 msec.

Example 3: Chromaticity of green phosphor applied to diffusion plate Green phosphor SrGa ₂ S ₄ : Eu, (Sr, Ba) SiO ₄ : Eu having different chromaticities was used for the diffusion plate 16 as a green phosphor. A layer was formed and the chromaticity of the green phosphor was measured. Since these phosphors SrGa ₂ S ₄ : Eu and (Sr, Ba) SiO ₄ : Eu contain Eu ²⁺ , the afterglow time of fluorescence is short.

(1) When green phosphor SrGa ₂ S ₄ : Eu is used 6 g of ethyl cellulose is dissolved in 300 mL of terpineol to prepare a binder, and 5 g of the phosphor is mixed with 20 mL of this binder to form a paste. One layer was applied to the diffusion plate 16. The chromaticity point of the green phosphor was (0.2640, 0.6555).

(2) When (Sr, Ba) SiO ₄ : Eu is used A binder is prepared by dissolving 6 g of ethylcellulose in 300 mL of terpineol, and 6.6 g of phosphor is mixed with 20 mL of this binder to form a paste, and printing is performed. One layer was applied to the diffusion plate 16 by the method. The chromaticity point of the green phosphor was (0.2740, 0.6104).

(3) When SrGa ₂ S ₄ : Eu and (Sr, Ba) SiO ₄ : Eu are used SrGa ₂ S ₄ : Eu phosphor is mixed in a paste form by mixing 2.5 g of phosphor with 20 mL of binder. And one layer (thickness 10 μm) was applied to the first diffusion plate. Further, (Sr, Ba) SiO ₄ : Eu phosphor was mixed with 3.3 g of phosphor with 20 mL of binder to form a paste, and one layer was applied to the second diffusion plate (thickness 10 μm).

When the first diffusion plate and the second diffusion plate were overlapped and evaluated, the chromaticity of the entire green phosphor was (0.2690, 0.6342). The chromaticity point of the green phosphor is an intermediate point between the chromaticity point when only SrGa ₂ S ₄ : Eu is used and the chromaticity point when only the (Sr, Ba) SiO ₄ : Eu phosphor is used (0 2690, 0.6330). That is, by using two types of phosphors having different chromaticities, it is possible to obtain a chromaticity that substantially matches an intermediate point between the chromaticity points of the two types of phosphors.

In addition, SrGa ₂ S ₄ : Eu phosphor is mixed with 2.5 g of phosphor with 20 mL of binder to form a paste, coated on the diffusion plate 16 with a single layer (thickness 10 μm), cured, and the first phosphor This is layer 18a. Further, (Sr, Ba) SiO ₄ : Eu phosphor is mixed with 3.3 g of phosphor in 20 mL of binder to form a paste, and one layer is coated on the first phosphor layer 18 a (thickness 10 μm) and cured. Thus, the second phosphor layer 18b is obtained. The chromaticity of the diffusion layer 23 in which the first phosphor layer 18a and the second phosphor layer 18b are formed on the diffusion plate 16 is the same as described above.

Comparative Example (Part 1)
As a comparative example, the afterglow time of the green phosphor in a normal CCFL is set to 0 immediately after the CCFL excitation is stopped, and the time until the brightness of the green fluorescence is reduced to 1/10 is 1/10 afterglow time. As evaluated. In the measurement of the afterglow time of the green phosphor in the CCFL, the intensity of the green fluorescence after the AC power supply of the CCFL is stopped is monitored with a pin diode through a green color filter that selectively transmits light in the green wavelength region, This was done by observing the decay of green fluorescence with an oscilloscope.

Comparative Example 1:
Blue phosphor on the inner surface of the glass tube _{(Sr x, Ba y, Ca} z, Mg (1-xyz)) 5 (PO 4) 3 Cl: Eu, green phosphor _{BaMgAl 10 O 17: Eu, Mn} , red phosphor In the CCFL coated with Y ₂ O ₃ : Eu, the 1/10 afterglow time of the green phosphor BaMgAl ₁₀ O ₁₇ : Eu, Mn was 12 msec.

Comparative Example 2:
Blue phosphor on the inner surface of the glass tube _{(Sr x, Ba y, Ca} z, Mg (1-xyz)) 5 (PO 4) 3 Cl: Eu, green phosphor LaPO _4: Tb, a red phosphor Y ₂ O ₃ The 1/10 afterglow time of the green phosphor LaPO ₄ : Tb in the CCFL coated with: Eu was 10 msec.

When the emission center of the green phosphor is Mn ²⁺ or Tb ^{3+ as} in Comparative Example 1 and Comparative Example 2 described above, the 1/10 afterglow time is as long as 12 msec and 10 msec. When the emission center of the green phosphor is Eu ²⁺ as in Example 2, the 1/10 afterglow time is about 0.2 msec, which is 1 / (about about 1/10 afterglow time in the comparative example. Since it is as short as 30 to 40), high-speed moving image characteristics can be improved.

  That is, even if the fluorescent lamp blinks at 60 Hz to 120 Hz, the 1/10 afterglow time of the phosphor used in the fluorescent lamp is as short as about 0.2 msec. It is possible to maintain a moving image characteristic.

If a phosphor containing Ce ³⁺ whose fluorescence emission mechanism is the same as Eu ²⁺ is used, the 1/10 afterglow time will be short and the high-speed moving picture characteristics will be improved, as in the above-described embodiment. Can do.

Examples of phosphors containing Ce ³⁺ include phosphors having a garnet structure, and Y ₃ Al ₃ Ga ₂ O ₁₂ : Ce (emission center wavelength 540 nm), Y ₂ GdAl ₃ Ga ₂ O ₁₂ : Ce (emission center). A phosphor such as YGd ₂ Al ₃ Ga ₂ O ₁₂ : Ce (emission center wavelength 562 nm), Gd ₃ Al ₃ Ga ₂ O ₁₂ : Ce (emission center wavelength 570 nm) may be used as the green phosphor. it can.

Example (2)
In the production of the diffusion layer 23 shown in FIG. 2 having the green phosphor layer 18 formed on the diffusion plate 16, the conditions of the composition and viscosity of the paint used for forming the green phosphor layer 18 were examined. The unevenness of the chromaticity distribution due to the diffusion plate (phosphor sheet) was confirmed visually.

  In addition, the illumination device including the phosphor layer 23 and the fluorescent lamp 40 shown in FIG. 2 is configured, and the afterglow time of the green phosphor is set to 0 immediately after the excitation of the fluorescent lamp is stopped, and the luminance of the green fluorescence is 1. The time until the point of time when it was reduced to / 10 was evaluated as 1/10 afterglow time. The measurement of the afterglow time of the green phosphor layer formed on the diffusion plate is performed by measuring the intensity of green fluorescence after stopping the AC power supply of the fluorescent lamp through a green color filter that selectively transmits light in the green wavelength region. This was done by monitoring with a pin diode and observing the decay of green fluorescence with an oscilloscope.

Example 1A: Lighting device in which a diffuser plate on which a green phosphor (SrGa ₂ S ₄ : Eu) layer is formed is disposed outside the CCFL Thermoplastic urethane resin (DIC Corporation: Pandex T-5265L) 1.5 g Is dissolved in 3.0 g of ethyl methyl ketone, and 1.0 g of green phosphor SrGa ₂ S ₄ : Eu is mixed and stirred to prepare a coating material (coating solution). This is applied to the diffusion plate 16 with a bar coater. Applied. The viscosity of this paint was measured using a Pheometric Scientific apparatus pheosol-G3000 at a temperature of 25 ° C. (the same applies to each of Examples and Comparative Examples described below) at a shear rate of 80 (1 / sec). It was 4,000 mPa · s (4 Pa · s). The thickness of the coating film was 20 μm.

The diffusion plate, and a blue phosphor on the inner wall _{(Sr x, Ba y, Ca} z, Mg (1-xyz)) 5 (PO 4) 3 Cl: Eu, red phosphor Y ₂ 0 _3: Eu is applied The lighting device was constituted by CCFL and used as the backlight of the liquid crystal panel. When is lit attaching the backlight to the liquid crystal panel, so that the white chromaticity point is near (0.300,0.300), a blue phosphor _{(Sr x, Ba y, Ca} z, Mg (1- The weight ratio of _xyz) ) ₅ (PO ₄ ) ₃ Cl: Eu and red phosphor Y ₂ O ₃ : Eu was searched by trial and error, and a mixture of blue phosphor and red phosphor was applied to CCFL. The exploratory test was conducted using a 32-inch LCD TV.

CCFL coated with a mixture of a blue phosphor and a red phosphor with a weight ratio (blue phosphor: red phosphor) = 73: 27 obtained as a result of the search test, and a green phosphor (SrGa ₂ S ₄ : The illuminating device was constituted by a diffusion plate coated with Eu), and this was attached to a liquid crystal panel as a backlight. As a result, the white chromaticity was (0.3024, 0.3077). As a result of taking out this backlight and evaluating the afterglow characteristics of the green phosphor, the 1/10 afterglow time of the green phosphor (SrGa ₂ S ₄ : Eu) was about 0.2 msec. In addition, unevenness in the chromaticity distribution due to the diffusion plate (phosphor sheet) could not be confirmed visually.

Example 2A: Lighting device in which a diffusion plate on which a green phosphor (SrGa ₂ S ₄ : Eu) layer is formed is arranged outside the CCFL Thermoplastic urethane resin (manufactured by DIC: Pandex T-5265H) 1.5 g Was dissolved in 6.6 g of cyclohexanone, mixed with green phosphor SrGa ₂ S ₄ : Eu, 0.53 g, and stirred to prepare a paint, which was applied to the diffusion plate 16 with a bar coater. The viscosity of the paint was 20,000 mPa · s (20 Pa · s) at a shear rate of 80 (1 / sec). The thickness of the coating film was 20 μm.

The diffusion plate, and a blue phosphor on the inner wall _{(Sr x, Ba y, Ca} z, Mg (1-xyz)) 5 (PO 4) 3 Cl: Eu, red phosphor Y ₂ 0 _3: Eu is applied The lighting device was constituted by CCFL and used as the backlight of the liquid crystal panel. When is lit attaching the backlight to the liquid crystal panel, so that the white chromaticity point is near (0.300,0.300), a blue phosphor _{(Sr x, Ba y, Ca} z, Mg (1- The weight ratio of _xyz) ) ₅ (PO ₄ ) ₃ Cl: Eu and red phosphor Y ₂ O ₃ : Eu was searched by trial and error, and a mixture of blue phosphor and red phosphor was applied to CCFL. The exploratory test was conducted using a 32-inch LCD TV.

As a result of attaching the backlight to the liquid crystal panel, the white chromaticity was (0.3024, 0.3077). As a result of taking out this backlight and evaluating the afterglow characteristics of the green phosphor, the 1/10 afterglow time of the green phosphor (SrGa ₂ S ₄ : Eu) was about 0.2 msec. In addition, unevenness in the chromaticity distribution due to the diffusion plate (phosphor sheet) could not be confirmed visually.

Example 3A: Illuminating device in which a diffuser plate on which a green phosphor (SrGa ₂ S ₄ : Eu) layer is formed is arranged outside the CCFL Acrylic monomer (Nippon Kayaku Co., Ltd .: KAYARAD DPHA (dipentaerythritol acrylate)) A green phosphor SrGa ₂ S ₄ : Eu, 1.0 g was mixed with 1.5 g and stirred to prepare a paint, which was applied to the diffusion plate 16 with a bar coater. The viscosity of this paint was 10,000 mPa · s (10 Pa · s) at a shear rate of 80 (1 / sec). The thickness of the coating film was 20 μm.

The diffusion plate, and a blue phosphor on the inner wall _{(Sr x, Ba y, Ca} z, Mg (1-xyz)) 5 (PO 4) 3 Cl: Eu, red phosphor Y ₂ 0 _3: Eu is applied The lighting device was constituted by CCFL and used as the backlight of the liquid crystal panel. When is lit attaching the backlight to the liquid crystal panel, so that the white chromaticity point is near (0.300,0.300), a blue phosphor _{(Sr x, Ba y, Ca} z, Mg (1- The weight ratio of _xyz) ) ₅ (PO ₄ ) ₃ Cl: Eu and red phosphor Y ₂ O ₃ : Eu was searched by trial and error, and a mixture of blue phosphor and red phosphor was applied to CCFL. The exploratory test was conducted using a 32-inch LCD TV.

As a result of attaching the backlight to the liquid crystal panel, the white chromaticity was (0.3024, 0.3077). As a result of taking out this backlight and evaluating the afterglow characteristics of the green phosphor, the 1/10 afterglow time of the green phosphor (SrGa ₂ S ₄ : Eu) was about 0.2 msec. In addition, unevenness in the chromaticity distribution due to the diffusion plate (phosphor sheet) could not be confirmed visually.

Example 4A: Illuminating device in which a diffuser plate on which a green phosphor ((Sr, Ba, Ca, Mg) ₂ SiO ₄ : Eu) layer is formed is disposed outside the CCFL. In Example 1A, the green phosphor (SrGa (Sr: Ba, Ca, Mg) ₂ SiO ₄ : Eu is used instead of ₂ S ₄ : Eu, and 1/10 of the remaining green phosphor (Sr, Ba, Ca, Mg) ₂ SiO ₄ : Eu Light time was evaluated.

In the same manner as in Example 1A, a paint containing a green phosphor (Sr, Ba, Ca, Mg) ₂ SiO ₄ : Eu was applied to the diffusion plate, and the blue phosphor (Sr _x , _{Ba y, Ca z, Mg (} 1-xyz)) 5 (PO 4) 3 Cl: Eu, red phosphor Y ₂ 0 _3: by Eu is applied CCFL, which the liquid crystal panel constituting the lighting device The backlight was used. The 1/10 afterglow time of the green phosphor (Sr, Ba, Ca, Mg) ₂ SiO ₄ : Eu in this backlight was also about 0.2 msec.

In the same manner as in Example 2A, a paint containing a green phosphor (Sr, Ba, Ca, Mg) ₂ SiO ₄ : Eu was applied to the diffusion plate 16, and a blue phosphor (Sr _x ) was applied to the diffusion plate and the inner wall. _{, Ba y, Ca z, Mg} (1-xyz)) 5 (PO 4) 3 Cl: Eu, red phosphor Y ₂ 0 _3: by Eu is applied CCFL, it constitutes the illumination device includes a liquid crystal panel The backlight. The 1/10 afterglow time of the green phosphor (Sr, Ba, Ca, Mg) ₂ SiO ₄ : Eu in this backlight was also about 0.2 msec.

Example 5A: Chromaticity of green phosphor applied to diffuser plate The diffuser plate 16 is coated with a paint containing green phosphors SrGa ₂ S ₄ : Eu and (Sr, Ba) SiO ₄ : Eu having different chromaticities. A green phosphor layer was formed and the chromaticity of the green phosphor was measured. Since these phosphors SrGa ₂ S ₄ : Eu and (Sr, Ba) SiO ₄ : Eu contain Eu ²⁺ , the afterglow time of fluorescence is short.

(1) When green phosphor SrGa ₂ S ₄ : Eu is used 1.5 g of urethane resin (manufactured by DIC: Pandex T-5265L) is dissolved in 3.0 g of ethyl methyl ketone, and green phosphor SrGa is added thereto. ₂ S ₄ : Eu, 1.0 g was mixed and stirred to prepare a paint (coating liquid), which was applied to the diffusion plate 16 with a bar coater. The viscosity of the paint was 4,010 mPa · s (4.01 Pa · s) at a shear rate of 80 (1 / sec). The thickness of the coating film was 20 μm. The chromaticity point of the green phosphor was (0.2640, 0.6555).

(2) When (Sr, Ba) SiO ₄ : Eu is used 1.5 g of urethane resin (manufactured by DIC: Pandex T-5265L) is dissolved in 3.0 g of ethyl methyl ketone, and green phosphor SrGa is added thereto. ₂ S ₄ : Eu, 1.3 g was mixed and stirred to prepare a coating material (coating solution), which was applied to the diffusion plate 16 with a bar coater. The viscosity of this paint was 4,005 mPa · s (4.005 Pa · s) at a shear rate of 80 (1 / sec). The thickness of the coating film was 21 μm. The chromaticity point of the green phosphor was (0.2740, 0.6104).

(3) When SrGa ₂ S ₄ : Eu and (Sr, Ba) SiO ₄ : Eu are used 1.5 g of urethane resin (manufactured by DIC: Pandex T-5265L) is dissolved in 3.0 g of ethyl methyl ketone. This was mixed with 0.5 g of SrGa ₂ S ₄ : Eu phosphor to form a paint, which was applied to the first diffusion plate with a bar coater (thickness 20 μm). Further, 1.5 g of urethane resin (manufactured by DIC: Pandex T-5265L) is dissolved in 3.0 g of ethyl methyl ketone, and 0.7 g of (Sr, Ba) SiO ₄ : Eu phosphor is mixed with the paint. And applied to the second diffusion plate with a bar coater (thickness 20 μm).

When the first diffusion plate and the second diffusion plate were overlapped and evaluated, the chromaticity of the entire green phosphor was (0.2690, 0.6342). The chromaticity point of the green phosphor is an intermediate point between the chromaticity point when only SrGa ₂ S ₄ : Eu is used and the chromaticity point when only the (Sr, Ba) SiO ₄ : Eu phosphor is used (0 2690, 0.6330). That is, by using two types of phosphors having different chromaticities, it is possible to obtain a chromaticity that substantially matches an intermediate point between the chromaticity points of the two types of phosphors.

Further, 1.5 g of urethane resin (manufactured by DIC: Pandex T-5265L) is dissolved in 3.0 g of ethyl methyl ketone, and 0.5 g of SrGa ₂ S ₄ : Eu phosphor is mixed with this to obtain a paint. Is applied to the diffusion plate 16 with a bar coater (thickness: 20 μm) and cured to form the first phosphor layer 18a. Furthermore, 1.5 g of urethane resin (DIC Corporation: Pandex T-5265L) is dissolved in 3.0 g of ethyl methyl ketone, and 0.7 g of (Sr, Ba) SiO ₄ : Eu phosphor is mixed therewith. This is applied on the first phosphor layer 18a with a bar coater (thickness 20 μm) and cured to form the second phosphor layer 18b. The chromaticity of the diffusion layer 23 in which the first phosphor layer 18a and the second phosphor layer 18b are formed on the diffusion plate 16 is the same as described above.

Comparative Example (Part 2)
Further, as a comparative example, the afterglow time of the green phosphor in a normal CCFL is set to 0 immediately after the CCFL excitation is stopped, and the time until the point where the luminance of the green fluorescence is reduced to 1/10 is 1/10 afterglow. Evaluated as light time. In the measurement of the afterglow time of the green phosphor in the CCFL, the intensity of the green fluorescence after the AC power supply of the CCFL is stopped is monitored with a pin diode through a green color filter that selectively transmits light in the green wavelength region, This was done by observing the decay of green fluorescence with an oscilloscope. Further, the unevenness of the chromaticity distribution due to the diffusion plate (phosphor sheet) was visually confirmed.

Comparative Example 1A:
1.5 g of urethane resin (manufactured by DIC: Pandex L) is dissolved in 5.0 g of ethyl methyl ketone, and then green phosphor SrGa ₂ S ₄ : Eu, 1.0 g is mixed and stirred to obtain a paint (application) (Liquid) was prepared and applied to the diffusion plate with a bar coater. The viscosity of the paint was 3,500 mPa · s (3.5 Pa · s) at a shear rate of 80 (1 / sec). The thickness of the coating film was 20 μm. As a result of attaching the backlight using this diffusion plate to the liquid crystal panel, it was confirmed that the chromaticity was partially changed by visual observation.

Comparative Example 1B:
1.5 g of urethane resin (manufactured by DIC: Pandex L) is dissolved in 3.0 g of cyclohexanone, and then green phosphor SrGa ₂ S ₄ : Eu, 1.0 g is mixed and stirred, and then paint (coating liquid) Was prepared. The viscosity of the paint was 28,000 mPa · s (28 Pa · s) at a shear rate of 80 (1 / sec). This was applied to the diffusion plate with a bar coater, but the coating solution did not spread and could not be applied.

Comparative Example 1C:
Blue phosphor on the inner surface of the glass tube _{(Sr x, Ba y, Ca} z, Mg (1-xyz)) 5 (PO 4) 3 Cl: Eu, green phosphor _{BaMgAl 10 O 17: Eu, Mn} , red phosphor The 1/10 afterglow time of the green phosphor BaMgAl ₁₀ O ₁₇ : Eu, Mn in the CCFL coated with a paint containing Y ₂ O ₃ : Eu was 12 msec.

Comparative Example 1D:
Blue phosphor on the inner surface of the glass tube _{(Sr x, Ba y, Ca} z, Mg (1-xyz)) 5 (PO 4) 3 Cl: Eu, green phosphor LaPO _4: Tb, a red phosphor Y ₂ O ₃ The 1/10 afterglow time of the green phosphor LaPO ₄ : Tb in the CCFL coated with a paint containing: Eu was 10 msec.

When the emission center of the green phosphor is Mn ²⁺ or Tb ^{3+ as} in Comparative Example 1C and Comparative Example 1D described above, the 1/10 afterglow time is as long as 12 msec and 10 msec. When the emission center of the green phosphor is Eu ²⁺ as in Example 2A, the 1/10 afterglow time is about 0.2 msec, which is 1 / (about 1/10 afterglow time in the comparative example. Since it is as short as 30 to 40), high-speed moving image characteristics can be improved.

  That is, even if the fluorescent lamp blinks at 60 Hz to 120 Hz, the 1/10 afterglow time of the phosphor used in the fluorescent lamp is as short as about 0.2 msec. It is possible to maintain a moving image characteristic.

If a phosphor containing Ce ³⁺ whose fluorescence emission mechanism is the same as Eu ²⁺ is used, the 1/10 afterglow time will be short and the high-speed moving picture characteristics will be improved, as in the above-described embodiment. Can do.

Examples of phosphors containing Ce ³⁺ include phosphors having a garnet structure, and Y ₃ Al ₃ Ga ₂ O ₁₂ : Ce (emission center wavelength 540 nm), Y ₂ GdAl ₃ Ga ₂ O ₁₂ : Ce (emission center). A phosphor such as YGd ₂ Al ₃ Ga ₂ O ₁₂ : Ce (emission center wavelength 562 nm), Gd ₃ Al ₃ Ga ₂ O ₁₂ : Ce (emission center wavelength 570 nm) may be used as the green phosphor. it can.

  The diffusion plate 16 in the above-described example (part 1) and example (part 2) is a PET film having a thickness of 188 μm made of a paint in which acrylic resin particles are dispersed in a transparent polyurethane resin as a light diffusing agent. It was formed by applying and curing at a thickness of about 30 μm.

Example (3)
An illuminating device comprising a diffusion film 9 (shown in FIG. 4) having a light diffusing layer 8 containing a green phosphor formed on a transparent support plate 6 and a fluorescent lamp 40 is constructed, and the afterglow time of the green phosphor Was evaluated as 1/10 afterglow time until the time when the brightness of green fluorescence decreased to 1/10 with 0 immediately after the excitation of the fluorescent lamp was stopped. The measurement of the afterglow time of the green phosphor layer formed on the diffusion film 9 is performed using a green color filter that selectively transmits green wavelength light after the AC power supply of the fluorescent lamp is stopped. This was done by monitoring with a pin diode and observing the decay of green fluorescence with an oscilloscope.

Example 1B: Illumination device in which a diffusion film having a light diffusion layer containing a green phosphor (SrGa ₂ S ₄ : Eu) is disposed outside the CCFL Green phosphor (SrGa ₂ S ₄ : Eu) After preparing the coating material which has a composition of (a)-(e), this was apply | coated on the transparent support plate 6, it dried, the diffusion layer 8 was formed, and the diffusion film 9 was produced.
(A) Green phosphor fine particles: SrGa ₂ S ₄ : Eu 15% by weight
(B) Diffusion particles: PMMA particles (8 μm diameter) 38% by weight
(C) Binder: Unidic V4263 (manufactured by Dainippon Ink Industries, Ltd.) 37% by weight
(D) Photopolymerization initiator: Darocur 1173 0.6% by weight
(E) Solvent: 9.4% by weight of methyl ethyl ketone
Said (a)-(e) was stirred for 1 minute with the stirring apparatus (HM-800: made by Keyence Corporation), and it was set as the coating material. The base material (transparent support plate 6) was PET (A4300: manufactured by Toyobo Co., Ltd.) (thickness: 188 μm), and the paint was applied with a bar coater. After coating, the coating film was dried at 80 ° C. for 2 minutes, and the coating film was cured by irradiating energy of 1,000 mJ / cm ² with a high-pressure mercury lamp, whereby a diffusion film 9 was produced. The thickness of the coating film was 25 μm.

  Note that Unidic V 4263 (Dainippon Ink Industries) is a urethane acrylate, an ultraviolet ray whose reaction is accelerated using an alkylphenone photopolymerization initiator such as Darocur 1173 (Ciba Specialty Chemicals). It is a curable resin.

  Moreover, a technopolymer (made by Sekisui Plastics Co., Ltd.) can be used as the PMMA particles used as the diffusing particles.

The diffusion film, and a blue phosphor on the inner wall _{(Sr x, Ba y, Ca} z, Mg (1-xyz)) 5 (PO 4) 3 Cl: Eu, red phosphor Y ₂ 0 _3: Eu is applied The lighting device was constituted by CCFL and used as the backlight of the liquid crystal panel. When is lit attaching the backlight to the liquid crystal panel, so that the white chromaticity point is near (0.300,0.300), a blue phosphor _{(Sr x, Ba y, Ca} z, Mg (1- The weight ratio of _xyz) ) ₅ (PO ₄ ) ₃ Cl: Eu and red phosphor Y ₂ O ₃ : Eu was searched by trial and error, and a mixture of blue phosphor and red phosphor was applied to CCFL. The exploratory test was conducted using a 32-inch LCD TV.

CCFL coated with a mixture of a blue phosphor and a red phosphor with a weight ratio (blue phosphor: red phosphor) = 73: 27 obtained as a result of the search test, and a green phosphor (SrGa ₂ S ₄ : The illuminating device was constituted by a diffusion plate coated with Eu), and this was attached to a liquid crystal panel as a backlight. As a result, the white chromaticity was (0.3024, 0.3077). As a result of taking out this backlight and evaluating the afterglow characteristics of the green phosphor, the 1/10 afterglow time of the green phosphor (SrGa ₂ S ₄ : Eu) was about 0.2 msec. Moreover, the color map distribution by the coating film thickness nonuniformity of the diffusion film containing fluorescent substance was not able to be confirmed visually. The light diffusion function was good.

Example 2B: Illumination device in which a diffusion film having a light diffusion layer containing a green phosphor (SrGa ₂ S ₄ : Eu) is disposed outside the CCFL In Example 1B, the binder is V4263 (manufactured by Dainippon Ink & Chemicals, Inc.) In place of T5265L (manufactured by Dainippon Ink & Chemicals, Inc.), a coating material having the following compositions (a) to (d) is prepared, applied onto the transparent support plate 6, dried, and then the diffusion layer. 8 was formed, and the diffusion film 9 was produced.
(A) Green phosphor fine particles: SrGa ₂ S ₄ : Eu: 10% by weight
(B) Diffusion particles: PMMA particles (8 μm diameter) 27% by weight
(C) Binder: T5265L (manufactured by Dainippon Ink Industries, Ltd.) 21% by weight
(D) Solvent: 42% by weight of methyl ethyl ketone
Said (a)-(d) was stirred for 1 minute with the stirring apparatus (HM-800: made by Keyence Corporation), and it was set as the coating material. The base material (transparent support plate 6) was PET (A4300: manufactured by Toyobo Co., Ltd.) (thickness: 188 μm), and the paint was applied with a bar coater. After application, the film was dried at 80 ° C. for 2 minutes to produce a diffusion film 9. The thickness of the coating film was 25 μm. Evaluation was performed in the same manner as in Example 1B. The results were comparable.

Example 3B: Illumination device in which a diffusion film having a light diffusion layer containing a green phosphor (SrGa ₂ S ₄ : Eu) is disposed outside the CCFL In Example 1B, the binder is V4263 (manufactured by Dainippon Ink Industries, Ltd.) In place of Byron 885 (manufactured by Toyobo Co., Ltd.), a coating material having the following compositions (a) to (d) is prepared, applied onto the transparent support plate 6, dried, and then the diffusion layer 8. And a diffusion film 9 was produced.
(A) Green phosphor fine particles: SrGa ₂ S ₄ : Eu: 10% by weight
(B) Diffusion particles: PMMA particles (8 μm diameter) 27% by weight
(C) Binder: Byron 885 (Toyobo Co., Ltd.) 21% by weight
(D) Solvent: 42% by weight of methyl ethyl ketone
Said (a)-(d) was stirred for 1 minute with the stirring apparatus (HM-800: made by Keyence Corporation), and it was set as the coating material. The base material (transparent support plate 6) was PET (A4300: manufactured by Toyobo Co., Ltd.) (thickness: 188 μm), and the paint was applied with a bar coater. After application, the film was dried at 80 ° C. for 2 minutes to produce a diffusion film 9. The thickness of the coating film was 25 μm. Evaluation was performed in the same manner as in Example 1B. The results were comparable. Byron 885 (manufactured by Toyobo Co., Ltd.) is such a polyester resin in general-purpose organic solvents such as methyl ethyl ketone and toluene.

Example 4B: Illumination device in which a diffusion film having a light diffusion layer containing a green phosphor (SrGa ₂ S ₄ : Eu) is arranged outside the CCFL In Example 2B, the following (a), except for diffusion particles: A coating material having the compositions (c) and (d) was prepared, and this was applied onto the transparent support plate 6 and then dried to form a diffusion layer 8, thereby producing a diffusion film 9.
(A) Green phosphor fine particles: SrGa ₂ S ₄ : Eu 18% by weight
(C) Binder: T5265L (manufactured by Dainippon Ink Industries, Ltd.) 27% by weight
(D) Solvent: 55% by weight of methyl ethyl ketone
Said (a), (c), (d) was stirred for 1 minute with the stirring apparatus (HM-800: made by Keyence Corporation), and it was set as the coating material. The base material (transparent support plate 6) was PET (A4300: manufactured by Toyobo Co., Ltd.) (thickness: 188 μm), and the paint was applied with a bar coater. After application, the film was dried at 80 ° C. for 2 minutes to produce a diffusion film 9. The thickness of the coating film was 23 μm. Evaluation was performed in the same manner as in Example 1B. The results were comparable.

Example 5B: Illumination device in which a diffusion film having a light diffusion layer containing a green phosphor (SrGa ₂ S ₄ : Eu) is disposed outside the CCFL In Example 3B, the following (a), except for diffusion particles: A coating material having the compositions (c) and (d) was prepared, and this was applied onto the transparent support plate 6 and then dried to form a diffusion layer 8, thereby producing a diffusion film 9.

The composition was as follows except for the diffusion particles.
(A) Green phosphor fine particles: SrGa ₂ S ₄ : Eu 18% by weight
(C) Binder: Byron 885 (manufactured by Toyobo Co., Ltd.) 30% by weight
(D) Solvent: 52% by weight of methyl ethyl ketone
Said (a), (c), (d) was stirred for 1 minute with the stirring apparatus (HM-800: made by Keyence Corporation), and it was set as the coating material. The base material was PET (A4300: manufactured by Toyobo Co., Ltd.), and the paint was applied with a bar coater. After application, the film was dried at 80 ° C. for 2 minutes to produce a diffusion film 9. The thickness of the coating film was 22 μm. Evaluation was performed in the same manner as in Example 1B. The results were comparable.

Example 6B: Illumination device in which a diffusion film having a light diffusion layer containing a green phosphor ((Sr, Ba, Ca, Mg) ₂ SiO ₄ : Eu) is disposed outside the CCFL In Example 1B, the green phosphor (SrGa ₂ S ₄ : Eu) is used instead of (Sr, Ba, Ca, Mg) ₂ SiO ₄ : Eu to prepare a paint, which is applied on the transparent support plate 6 and then dried. Then, the diffusion layer 8 was formed, the diffusion film 9 was produced, and the 1/10 afterglow time of the green phosphor (Sr, Ba, Ca, Mg) ₂ SiO ₄ : Eu was evaluated.

In the same manner as in Example 1B, a diffusion plate film containing a green phosphor (Sr, Ba, Ca, Mg) ₂ SiO ₄ : Eu was prepared, and this diffusion plate film and a blue phosphor (Sr _x , _{Ba y, Ca z, Mg (} 1-xyz)) 5 (PO 4) 3 Cl: Eu, red phosphor Y ₂ 0 _3: by Eu is applied CCFL, which the liquid crystal panel constituting the lighting device The backlight was used. The 1/10 afterglow time of the green phosphor (Sr, Ba, Ca, Mg) ₂ SiO ₄ : Eu in this backlight was also about 0.2 msec.

Example 7B: A diffusion film having a light diffusion layer containing two types of green phosphors (SrGa ₂ S ₄ : Eu, (Sr, Ba, Ca, Mg) ₂ SiO ₄ : Eu) was placed outside the CCFL. Illumination Device In Example 1B, two types of green phosphors (SrGa ₂ S ₄ : Eu, (Sr, Ba, Ca, Mg) ₂ SiO ₄ : Eu) are used for chromaticity adjustment, and the following (a1) , (A2), (b) to (e) were prepared, and this was applied on the transparent support plate 6 and then dried to form a diffusion layer 8 to produce a diffusion film 9. .
(A1) Green phosphor: SrGa ₂ S ₄ : Eu 11% by weight
(A2) Green phosphor: Sr, Ba) SiO ₄ : Eu 14% by weight
(B) Diffusion particles: PMMA particles (8 μm diameter) 32% by weight
(C) Binder: Unidic V4263 (manufactured by Dainippon Ink Industries, Ltd.) 33% by weight
(D) Solvent: 9.4% by weight methyl ethyl ketone
(E) Photopolymerization initiator: Darocur 1173 0.6% by weight
The above (a1), (a2), and (b) to (e) were stirred for 1 minute with a stirrer (HM-800: manufactured by Keyence Corporation) to obtain a paint. The base material (transparent support plate 6) was PET (A4300: manufactured by Toyobo Co., Ltd.) (thickness: 188 μm), and the paint was applied with a bar coater. After coating, the film was dried at 80 ° C. for 2 minutes, and the coating film was cured by irradiating energy of 1000 mJ / cm ² with a high-pressure mercury lamp. The thickness of the coating film was 25 μm.

  The chromaticity when the above two kinds of phosphor fine particles were added alone was (0.2640, 0.6555) and (0.2740, 0.6104), whereas the two kinds in Example 7B (0.2690, 0.6342) in the phosphor fine particle mixed system. This substantially coincided with the intermediate point (0.2690, 0.6330) of the chromaticity point of the diffusion film containing each phosphor. That is, by using two types of phosphors having different chromaticities, it is possible to obtain a chromaticity that substantially matches an intermediate point between the chromaticity points of the two types of phosphors.

Comparative Example (Part 3)
Comparative Example 2A:
In Example 1B, a paint having a composition excluding the diffusion fine particles was prepared, and this was applied on the transparent support plate 6 and then dried to form a diffusion layer 8, thereby producing a diffusion film 9. This diffusion film was inferior in diffusibility, and the luminance distribution was confirmed visually.

Comparative Example 2B:
In Example 1B, a coating material having the following compositions (a) to (e) with a reduced amount of diffusion fine particles to be mixed was prepared, applied to the transparent support plate 6, dried, and then the diffusion layer 8. And a diffusion film 9 was produced. This diffusion film was inferior in diffusibility, and the luminance distribution was confirmed visually.
(A) Green phosphor fine particles: SrGa ₂ S ₄ : Eu 16% by weight
(B) Diffusion particles: PMMA particles (8 μm diameter) 16% by weight
(C) Binder: Unidic V4263 (manufactured by Dainippon Ink Industries, Ltd.) 64% by weight
(D) Solvent: methyl ethyl ketone 3.4% by weight
(E) Photopolymerization initiator: Darocur 1173 0.6% by weight

  In the above description of the embodiment, the lighting device using a specific phosphor has been described as an example. However, the present invention is not limited to this. For example, the phosphors shown below can be used in the configurations shown in FIGS. When high-speed moving image display is performed by blinking the fluorescent lamp at 120 Hz, the 1/10 afterglow time of the phosphor may be 0.2 msec or less.

  As a blue inorganic phosphor having a light emission color from blue to blue-green, alkaline earth metal halogen apatite phosphor, alkaline earth metal borate halogen phosphor, alkaline earth metal aluminate phosphor, alkaline earth A metal silicon oxynitride phosphor, an alkaline earth metal silicon nitride phosphor or the like can be used.

Specifically, Ca ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, Sr ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, (Sr, Mg, Ca) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, (Sr, Ca) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, (Sr, Ca) ₁₀ (PO ₄ ) ₆ Cl ₂ .nB ₂ O ₃ : Eu, (Sr, Ca, Ba) ₅ (PO ₄ ) ₃ Cl: Eu , (Ba, Ca, Mg) ₅ (PO ₄ ) ₃ Cl: Eu, (Ba, Sr) ₅ (PO ₄ ) ₃ (F, Cl): Eu, Sr ₅ (PO ₄ ) ₃ Cl: Eu, (Sr , Mg) ₂ P ₂ O ₇ : Eu, Sr ₂ P ₂ O ₇ : Eu, BaMgAl ₁₀ O ₁₇ : Eu, (Ba, Mg) Al ₁₀ O ₁₇ : Eu, BaMg ₂ Al ₁₆ O ₂₇ : Eu, (Ba Mg) ₂ Al ₁₅ O ₂₇ : Eu, Sr ₄ Al ₁₄ O ₂₅ : Eu, Ba ₃ MgSi ₂ O ₈ : Eu, Ca ₂ B ₅ O ₉ Cl: Eu, BaSi ₂ O ₂ N ₂ : Eu, SrS: Eu, (Ca, Ba, Sr) S: Eu, Y ₂ SiO ₅ : Ce, La _0.7 Gd _0.3 OBr: Ce, and the like can be used.

  As a green inorganic phosphor having an emission color in a green to orange region, a rare earth aluminate phosphor having a garnet structure, an alkaline earth metal aluminate phosphor activated by at least Eu, activated by at least Eu Alkaline earth metal silicate phosphors activated, at least Eu or Ce activated alkaline earth metal silicon oxynitride phosphors, at least Eu or Ce activated alkaline earth metal gallium sulfide phosphors, etc. can do.

Specifically, SrGa ₂ S ₄ : Eu, (Sr, Ca, Ba) (Al, Ga) ₂ S ₄ : Eu, (Ca, Sr, Ba) Ga ₂ S ₄ : Eu, BaAl ₂ O ₄ : Eu SrAl ₂ O ₄ : Eu, (Ba, Sr) Al ₂ O ₄ : Eu, CaAl ₂ O ₄ : Eu, Sr ₄ Al ₄ O ₂₅ : Eu, Ba ₂ SiO ₄ : Eu, (Sr, Ba, Mg) _{2 SiO 4: Eu, (Ba} , Sr) 2 SiO 4: Eu, Ba 2 MgSi 2 O 7: Eu, Ca 3 (1-x) Mg 3 Si 4 O 28: Eu x, Ba 2 (Mg, Zn) Si ₂ O ₇ : Eu, BaSi ₂ O ₂ N ₂ : Eu, (Sr, Ca) Si ₂ O ₂ N ₂ : Eu, β-SiAlON: Eu, Lu ₃ Al ₅ O ₁₂ : Ce, Y ₃ Al ₅ O _{12: Ce, Y 3 (Al} , Ga) 5 O 12: Ce, (Y, Gd) 3 Al 5 O 12: Ce, Y 2 (Al, Ga) 5 O 12: Ce _{Ca 3 Sc 2 Si 3 O 12} : it can be used such as Ce.

  A monoclinic or orthorhombic alkaline earth metal silicon nitride phosphor or the like can be used as the red inorganic phosphor having an emission color in the orange to red-based region.

Specifically, Ca ₂ Si ₅ N ₈ : Eu, Sr ₂ Si ₅ N ₈ : Eu, (Sr, Ca) ₂ Si ₅ N ₈ : Eu, Ba ₂ Si ₅ N ₈ : Eu, CaAlSiN ₃ : Eu, YVO ₄ : Eu, Y (P, V) O ₄ : Eu, Sr ₂ CeO ₄ : Eu, (Y, Gd) BO ₃ : Eu, SrS: Eu, CaS: Eu, Ca, Sr) S: Eu, ( CaBaSr) S: Eu, Y ₂ O ₃ : Eu, Gd ₂ O ₂ S: Eu, La ₂ O ₂ S: Eu, Y ₂ O ₂ S: Eu, SrY ₂ S ₄ : Eu, etc. can be used. .

  In addition, the fluorescent lamp constituting the illumination device is not limited to the straight tube fluorescent lamp having a linear shape as shown in FIGS. 1 to 10, and has a curved shape such as a U shape or a spiral shape. A curved tube fluorescent lamp may be used. Furthermore, the number of fluorescent lamps constituting the illumination device can be arbitrarily set.

  Further, the diffusion plate 16 on which the green phosphor layer 18 is formed may include various known light diffusing agents. In addition to the green phosphor, the diffusion layer (light diffusion layer) 8 containing the green phosphor is made of resin fine particles such as PMMA (polymethyl methacrylate) particles and crosslinked polystyrene (PS) particles as the light diffusion particles, and inorganic materials. Fine particles can also be used. Various binders (binders) can be used for the formation of the green phosphor layer 18 and the formation of the diffusion layer (light diffusion layer) 8 containing the green phosphor.

As described above, according to the present invention, there are provided an illuminating device having a fluorescent lamp, a display device using the same, and a light diffusing film that can be suitably used for a liquid crystal display device that performs high-speed moving image display. be able to.

It is sectional drawing explaining schematic structure of the illuminating device which has arrange | positioned the green fluorescent substance outside the fluorescent lamp in embodiment of this invention. It is sectional drawing explaining schematic structure of the illuminating device which has arrange | positioned the green fluorescent substance outside the fluorescent lamp same as the above. It is sectional drawing explaining schematic structure of the illuminating device which has arrange | positioned multiple types of green fluorescent substance outside a fluorescent lamp same as the above. It is sectional drawing explaining schematic structure of the illuminating device which has arrange | positioned the green fluorescent substance outside the fluorescent lamp same as the above. It is sectional drawing explaining schematic structure of the liquid crystal display device which uses a direct type backlight same as the above. It is sectional drawing explaining schematic structure of the liquid crystal display device which uses a direct type backlight same as the above. It is sectional drawing explaining schematic structure of the liquid crystal display device which uses a side edge type | mold backlight same as the above. It is sectional drawing explaining schematic structure of the liquid crystal display device which uses a side edge type | mold backlight same as the above. It is sectional drawing explaining schematic structure of the liquid crystal display device which uses a side edge type | mold backlight same as the above. It is sectional drawing explaining schematic structure of the illuminating device which has arrange | positioned the green fluorescent substance outside the fluorescent lamp same as the above. It is the schematic which shows the lamp | ramp for using for a color sequential illumination apparatus in a prior art. FIG. 2 is a simplified diagram showing a variable color fluorescent lamp.

Explanation of symbols

1a, 1a ', 1b, 1c, 1c' ... liquid crystal display device, 2a, 2b, 2c ... lighting device,
3 ... Liquid crystal panel, 6 ... Transparent support, 8 ... Diffusion layer containing green phosphor, 9 ... Diffusion film,
10a ... red blue phosphor layer, 10b ... green phosphor layer, 11, 21a ... glass tube,
12a ... Cathode side internal electrode, 12b ... Anode side internal electrode, 13a ... Anode side conductor wire,
13b ... Anode-side conductor wire, 14a ... Cathode-side external electrode, 14b ... Anode-side external electrode,
DESCRIPTION OF SYMBOLS 15 ... Coil, 16 ... Diffusing plate, 18 ... Green fluorescent substance layer, 18a ... Green fluorescent substance layer-1,
18b ... green phosphor layer-2, 19a ... cathode side filament,
19b ... Anode-side filament, 21b ... Transparent coating film, 22 ... Reflector, 23 ... Diffusion layer,
24 ... Prism sheet, 25 ... Diffusion sheet, 26, 26a ... Light guide plate,
31A, 31B ... deflection plates, 32A, 32B ... glass substrates, 33 ... transparent pixel electrodes,
34 ... Liquid crystal layer, 35 ... Transparent electrode, 36 ... Color filter, 37 ... Black matrix,
40 ... fluorescent lamp, 40a ... cold cathode fluorescent lamp, 40b ... hot cathode fluorescent lamp,
40c: external electrode fluorescent lamp, 40d: electrodeless fluorescent lamp, LL: lamp light,
LO: Display light, LO _r : Red display light, LO _g : Green display light, LO _b : Blue display light,
WL ... White light

Claims (19)

A fluorescent lamp that emits blue light and red light by the blue phosphor and red phosphor applied on the inner surface;
A green phosphor layer disposed outside the fluorescent lamp and including a green phosphor having Eu ²⁺ or Ce ³⁺ as an emission center, and the green phosphor is excited by the blue light to emit light. An illumination device that emits white light by mixing green light, the red light, and the blue light.   The lighting device according to claim 1, wherein the green phosphor layer is formed on an outer surface of the fluorescent lamp.   The lighting device according to claim 1, wherein the green phosphor layer is formed on a light diffusing plate disposed outside the fluorescent lamp.   The lighting device according to claim 3, wherein the green phosphor layers each including the different types of green phosphors are formed on the light diffusion plate.   The lighting device according to claim 1, wherein the green phosphor layer has light diffusibility and constitutes a light diffusing plate.   The lighting device according to claim 5, wherein the green phosphor layer includes different types of the green phosphors.   The lighting device according to claim 5, wherein the green phosphor layer includes light diffusing particles.   The lighting device according to claim 7, wherein the light diffusing particles are resin fine particles.   The lighting apparatus according to claim 1, wherein a 1/10 afterglow time of the green phosphor is 0.2 msec or less.   The lighting device according to claim 1, wherein the fluorescent lamp is a cold cathode fluorescent lamp. A transparent sheet substrate;
A resin binder, a green phosphor having a light emission center of Eu ²⁺ or Ce ³⁺ , and a light diffusion layer formed on the sheet-like substrate; The green light, which is disposed outside the fluorescent lamp coated with the phosphor and emits blue light and red light, is emitted by exciting the green phosphor with the blue light, and the red light and the blue light are mixed. A light diffusing film used in a lighting device that emits white light.   The light diffusion film according to claim 11, wherein the light diffusion layer includes different types of the green phosphors.   The light diffusion film according to claim 11, wherein the light diffusion layer includes light diffusion particles.   The light diffusion film according to claim 13, wherein the light diffusion particles are resin fine particles.   The light diffusion film according to claim 11, wherein the 1/10 afterglow time of the green phosphor is 0.2 msec or less.   The display apparatus which has an illuminating device of any one of Claims 1-10.   The display device according to claim 16, comprising a liquid crystal panel.   The display device according to claim 16, wherein the illumination device is a backlight.   The display device according to claim 18, further comprising: a pixel portion, wherein on / off of the pixel portion is synchronized with blinking of the backlight.

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