JP2008034201A - Lighting device and light control panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bright illumination device and a light control panel in which a phosphor has high luminous efficiency.
In an LED lighting device including an LED array section (1) and a light control layer, the light control layer has a light emitting layer (2) made of a fluid in which a phosphor is dissolved. The light emitting layer is a red light emitting layer made of a fluid in which a red light emitting phosphor is dissolved, and the light control layer has a yellow light emitting layer (3) adjacent to the red light emitting layer.
[Selection] Figure 1

Description

  The present invention relates to a lighting device and a light control panel.

  In recent years, LED elements have attracted attention as next-generation lighting devices that replace fluorescent lamps along with a rapid increase in luminous efficiency. However, the object illuminated by the current LED lighting device is particularly lacking in red vividness, and when a person is illuminated, there is a problem that the flesh color is poor. Such characteristics are caused by a weak spectrum intensity in the red region in the spectrum of current LED lighting devices. Accordingly, when such an LED lighting device is used for lighting effects such as stage lighting, it may be difficult to produce an effective rendering effect.

  In order to solve this problem, a red phosphor that can be excited by near-ultraviolet or blue light, which is the emission center wavelength of the LED chip, is required. However, when the red phosphor layer made of an inorganic compound is provided in the LED illumination device, the efficiency with which light can be extracted outside the illumination device is greatly reduced due to the increased light scattering effect.

  In such a situation, when a polymer thin film in which a rare earth complex that is a red organic phosphor is dissolved is placed adjacent to the yellow fluorescent layer, sufficient red spectrum intensity cannot be obtained.

  On the other hand, the temperature characteristics of phosphors are generally such that the emission characteristics, that is, the quantum yield, decrease as the temperature rises, regardless of whether the phosphors are organic or inorganic. Therefore, there is a problem that due to the heat generation of the LED chip array, radiant heat is transmitted to the light control layer or the fluorescent light emitting layer used in combination therewith, and the luminous efficiency of the phosphor is lowered.

  This invention is made | formed in view of this condition, and it aims at providing the bright illuminating device and light control panel with the high luminous efficiency of fluorescent substance.

  In order to solve the above problems, a first aspect of the present invention is a lighting device including a light-emitting element and a light-control layer that adjusts light from the light-emitting element, wherein the light-control layer dissolves a phosphor. An illuminating device having a light emitting layer made of a fluid is provided.

  In such a lighting device, the light emitting layer may be a red light emitting layer made of a fluid in which a red light emitting phosphor is dissolved. The light control layer may have a yellow light emitting layer adjacent to the red light emitting layer. In these cases, a rare earth complex phosphor can be used as the red light-emitting phosphor.

As the rare earth complex phosphor, a europium complex having a structure represented by the following formula (1) can be used.

(In the formula, R ^{1 to} R ⁹ are each an alkyl group or an alkoxy group having a straight chain or branched structure having 20 or less carbon atoms, a phenyl group, a biphenyl group, a naphthyl group, a heterocyclic group, and a substituent thereof. Except when selected from the group consisting of a hydrogen atom and a deuterium atom, and R ¹ -R ⁶ are all the same.)
As the rare earth complex phosphor, a europium complex having a structure represented by the following formula (2) can be used.

(In the formula, R ^{1 to} R ⁷ are each an alkyl group or an alkoxy group having a straight chain or branched structure having 20 or less carbon atoms, a phenyl group, a biphenyl group, a naphthyl group, a heterocyclic group, and a substituent thereof. (N is an integer of 2 or more and 20 or less, except when selected from the group consisting of a hydrogen atom and a deuterium atom, and R ¹ -R ⁴ are all the same.)
According to a second aspect of the present invention, there is provided a light emitting device, a light control layer having a light emitting layer in which a fluid in which a phosphor is dissolved in a medium is contained in a transparent cell, and the fluid connected to the transparent cell. Provided is a lighting device comprising a circulation means for circulation.

  In such a lighting device, the light emitting layer may be a red light emitting layer made of a fluid in which a red light emitting phosphor is dissolved. A yellow light emitting layer can be disposed on the outer wall or the inner wall of the transparent cell. A plurality of the yellow light emitting layers can be arranged in a lattice pattern.

  Furthermore, the medium in which the phosphor is dissolved can exhibit a liquid crystal phase. Further, the circulation means can comprise a cooling means or a heat dissipation means.

  According to a third aspect of the present invention, in the LED illumination device including the LED array unit and the light control layer including the first phosphor and the second phosphor, the first phosphor is the second fluorescence. Provided is a lighting device characterized by being dispersed in a phase-separated matrix polymer containing a body.

  In such an illumination device, the first phosphor may be a red light-emitting phosphor and the second phosphor may be a yellow light-emitting phosphor.

  According to a fourth aspect of the present invention, there is provided a light control panel comprising a light emitting layer made of a fluid in which a phosphor is dissolved.

  In such a light control panel, the light emitting layer can be a red light emitting layer made of a fluid in which a red light emitting phosphor is dissolved. A yellow light emitting layer can be disposed adjacent to the red light emitting layer. In these cases, the rare earth complex phosphor described above can be used as the red light-emitting phosphor.

  According to the present invention, since the light control panel has a transparent light emitting layer made of a fluid in which a phosphor is dissolved, light scattering does not occur. Extraction efficiency is improved. Further, by circulating the fluid in which the phosphor is dissolved, heat from the element is removed by heat dissipation or cooling, and the temperature of the phosphor can be kept low. As a result, the luminous efficiency of the phosphor can be increased, and an increase in fluorescence intensity can be realized.

  The best mode for carrying out the invention will be described below.

  FIG. 1: shows the schematic side view of the LED lighting apparatus which concerns on the 1st Embodiment of this invention. In FIG. 1, a plurality of LED elements 1 are arranged in an array in a parabolic shape, and a light control layer composed of an organic phosphor cell 2 containing a phosphor, for example, a fluid in which a red light-emitting phosphor is dissolved is arranged in the optical path. Has been. The organic phosphor cell 2 includes a fluid inlet 4 at the bottom and a fluid outlet 5 at the top. The inlet 4 and the outlet 5 are connected by a pipe 6. The fluid in the organic phosphor cell 2 circulates through the pipe 6.

  The pipe 6 may be provided with a cooler or a radiator 7. Even if only the pipe line 6 is used, the fluid whose temperature has risen due to the heat from the LED element 1 is cooled by natural cooling, but by providing a cooler or a radiator 7, more effective cooling of the fluid is possible. Is possible. In addition, the fluid can be circulated only in the pipe line 6 by the convection of the fluid in the organic phosphor cell 2, but a forced circulation means may be separately provided in the pipe line 6.

  In FIG. 1, an inorganic yellow light emitting layer 3 is disposed as necessary adjacent to the organic phosphor cell 2, and constitutes a light control layer by both.

  When the LED element 1 is a white LED element, the inorganic yellow light emitting layer 3 is not necessary, and only the organic phosphor cell 2 is disposed. When the LED element 1 is a blue LED element, the inorganic yellow light emitting layer 3 is disposed adjacent to the organic phosphor cell 2.

  In the LED illumination device configured as described above, the red light-emitting phosphor is dissolved in the fluid and thus becomes transparent, so that light scattering does not occur, and the light extraction efficiency of the LED illumination device is improved by light scattering. There is no decline.

  In addition, by increasing the spectral intensity in the red region, it is possible to realize a bright illumination device that can clearly illuminate red and human skin color.

  As shown in FIG. 2, the fluorescence intensity of the organic phosphor tends to be higher when dissolved in the solution than when contained in the solid thin film.

  FIG. 2 shows a case where 1% by weight of the red light emitting phosphor (the following formula (4)) is dissolved in a solvent (acetone) (curve 1), and 5% by weight of the red light emitting phosphor (the following formula (4) The fluorescence intensity when dissolved in a solvent (acetone) (curve 2) and when 1% by weight of red-emitting phosphor (the following formula (1) is dispersed in a solid thin film (silicone) (curve 3) 2, it can be seen that the red fluorescent intensity is much higher when the organic phosphor is dissolved in the solution than when it is dispersed in the solid thin film.

  Further, in the LED illumination device shown in FIG. 1, the inorganic yellow light emitting layer 3 is also cooled while suppressing the temperature rise of the organic phosphor cell 2 by circulation of the fluid medium. Thus, the luminous efficiency is not lowered by suppressing the temperature rise of the phosphor. Further, as shown in FIG. 1, when a large number of LED chip arrays 1 are arranged densely, the heat dissipation state is deteriorated, so that the effect of radiating and cooling by circulating a fluid medium is particularly exerted. .

  The red phosphor used in the LED lighting device according to the first embodiment of the present invention is preferably a trivalent europium complex that has a stable emission color and provides strong emission. Among these, a europium complex having a phosphine oxide compound and a β-diketone as a ligand is excellent in dispersibility in a resin and excellent in absorption efficiency of ultraviolet, near-ultraviolet, and blue-violet light, so that it is easy to obtain stronger light emission. Furthermore, among the above europium complexes, those having two kinds of phosphine oxides having different molecular structures as ligands are most excellent in resin dispersibility and light absorption efficiency, and are more desirable.

Such a europium complex has, for example, a structure represented by the following formula (1), but the present invention is not limited to this.

(In the formula, R ^{1 to} R ⁹ are each an alkyl group or an alkoxy group having a straight chain or branched structure having 20 or less carbon atoms, a phenyl group, a biphenyl group, a naphthyl group, a heterocyclic group, and a substituent thereof. Except when selected from the group consisting of a hydrogen atom and a deuterium atom, and R ¹ -R ⁶ are all the same.)
Moreover, since a europium complex as shown in the following formula (2) is excellent in light and thermal durability, it can cope with lighting of LED lighting for a long time, which is preferable.

(In the formula, R ^{1 to} R ⁷ are each an alkyl group or an alkoxy group having a straight chain or branched structure having 20 or less carbon atoms, a phenyl group, a biphenyl group, a naphthyl group, a heterocyclic group, and a substituent thereof. N is an integer of 2 or more and 20 or less, more preferably an integer of 3 or more and 5 or less, except when selected from the group consisting of a hydrogen atom and a deuterium atom and R ¹ -R ⁴ are all the same. )
Solvents that dissolve the above organic phosphors to form fluids have a high boiling point, are not easily volatilized, are flame retardant, and have the property of dissolving polar compounds such as organic phosphors at high concentrations. It is desirable that Specific examples include silicon oil, fluorine-based liquid crystal material, and cyanobiphenyl-based liquid crystal material, but are not limited thereto. A solvent such as xylene having a relatively large boiling point can also be used.

The inorganic yellow light emitting layer 3 is obtained by dispersing an inorganic yellow light emitting phosphor in a matrix resin. As the inorganic yellow light emitting phosphor, YAG, Sr ₂ SiO ₄ : Eu can be used, and as the matrix resin, a transparent resin that does not dissolve in the fluid medium of the light emitting layer cell, for example, a fluorine-based acrylic resin, polystyrene, polyester A silicone resin can be used.

  FIG. 3 shows an LED lighting device according to the second embodiment of the present invention. In the LED lighting device shown in FIG. 3, the organic phosphor cell 12 arranged in the optical path of the LED element 11 includes a glass cell 13 made of glass and a flow in which the phosphor contained therein is dissolved. It is composed of a conductive medium 14. In FIG. 3, the inorganic yellow light emitting layer 15 is disposed on the side opposite to the LED element 11 inside the organic phosphor cell 12, but may be disposed outside the organic phosphor cell 12.

  As in the LED lighting device shown in FIG. 3, the inorganic yellow light emitting layer 15 is disposed in close contact with the glass wall inside the glass cell 13, so that the fluid medium 14 and the inorganic yellow light emitting layer 15 are liquid-solid without gaps. It is possible to realize a light control layer that contacts at the interface and has a small optical loss. Further, as shown in FIG. 1, by circulating and replacing the fluid medium 14, the temperature rise of the fluid medium 14 is suppressed, the cooling effect of the inorganic yellow phosphor layer 15 is improved, and the luminous efficiency of the phosphor is lowered. Can be prevented.

  FIG. 4 shows an LED lighting device according to the third embodiment of the present invention. In the LED illumination device shown in FIG. 4, the LED chip array 21 is disposed in close contact with the organic phosphor cell 12. As described above, the LED chip array 21 is disposed in close contact with the organic phosphor cell 12, whereby the optical loss due to the refractive index gap can be reduced. In the LED lighting device shown in FIG. 4, the inorganic yellow light emitting layer 15 is disposed outside the organic phosphor cell 12. The inorganic yellow light emitting layer 15 is disposed on the LED chip array 21 side in FIG. 4A and on the opposite side of the LED chip array 21 in FIG. 4B.

  FIG. 5 shows a light control panel for an LED lighting device according to the fourth embodiment of the present invention. In the LED lighting device shown in FIG. 5, a plurality of inorganic yellow fluorescent layers 31 are arranged in a lattice shape in close contact with the glass wall inside the glass cell 13. By arranging a plurality of inorganic yellow fluorescent layers 31 in this way, the spectral intensity in the red region can be further increased.

  FIG. 6 shows a light control panel for an LED lighting device according to a fifth embodiment of the present invention. In the light control panel shown in FIG. 6, the organic red light emitting phosphor 43 is phase-separated and dispersed in the form of droplets in the inorganic yellow phosphor layer in which the inorganic yellow light emitting phosphor 42 is dispersed in the matrix resin 41. Yes. Thus, by combining and dispersing the inorganic yellow light-emitting phosphor 42 and the organic red light-emitting phosphor 43, a light control panel having a high spectral intensity in the red region can be easily obtained.

  Hereinafter, various examples and comparative examples of the present invention will be described.

Example 1
As a red light emitting phosphor, a europium complex having a structure represented by the following formula (3) is used. This is dissolved in xylene to form a solution having a concentration of 20 wt%, and injected into a glass cell having an inner wall thickness of 1 mm. A light emitting cell was formed. Next, an LED lighting device as shown in FIG. 1 was prototyped by installing an inorganic phosphor layer in which 20 wt% of a silicate inorganic phosphor was dispersed in a silicon polymer outside the glass cell. As the LED element, a blue LED having an emission center wavelength of 460 nm was used.

According to the LED lighting device configured in this way, the color rendering index was increased by 7 for Ra, increased by 46 for R9, and increased by 14 for R15, compared to the case where only the inorganic phosphor layer was disposed. .

Example 2
An LED lighting device similar to that of Example 1 was prototyped except that a europium complex having a structure represented by the following formula (4) was used as the red light-emitting phosphor.

  According to the LED illuminating device thus configured, the color rendering index was increased by 10 for Ra, increased by 52 for R9, and increased by 16 for R15, compared to the case where only the inorganic phosphor layer was disposed. .

The LED illumination device according to the present example was more effective than the LED illumination device according to Example 1 because the phosphor represented by the following formula (4) is the phosphor represented by the above formula (3). This is probably because the fluorescence intensity is large compared to the effect of increasing the color rendering index.

Example 3
An LED lighting device similar to that of Example 1 was made experimentally except that the light control layer having the structure shown in FIG.

  According to the LED illuminating device thus configured, the color rendering index increased by 8 for Ra, increased by 45 for R9, and increased by 15 for R15, compared to the case where only the inorganic phosphor layer was disposed. .

  According to the LED lighting apparatus according to the present example, the organic light emitting cell and the inorganic phosphor layer are in contact with each other without any gap, so that it is considered that there is little optical loss and the increase in red spectral intensity is large.

Example 4
An LED lighting device shown in FIG. 5 having the same material configuration as that of Example 1 except that the concentration of the inorganic phosphor was set to 30 wt% was prototyped.

  According to the LED illuminating device thus configured, the color rendering index increased by 8 for Ra, increased by 45 for R9, and increased by 15 for R15, compared to the case where only the inorganic phosphor layer was disposed. .

  According to the LED illumination device according to the present embodiment, since the red light that has passed through the organic light emitting cell directly goes out of the LED illumination device, there is little optical loss and the increase in red spectral intensity is large. It is considered a thing.

Example 5
The light control panel shown in FIG. 6 is obtained using the red light-emitting phosphor and the inorganic phosphor used in Example 1, using a non-volatile solvent such as silicone oil and PMMA (polymerized with Lucillin TPO) as a matrix polymer. A prototype LED lighting device was prepared.

  According to the LED lighting device thus configured, the color rendering index was increased by 10 for Ra, increased by 48 for R9, and increased by 18 for R15, compared to the case where only the inorganic phosphor layer was disposed. .

Example 6
When the LED lighting device was prototyped with the configuration of only the inorganic fluorescent layer sheet, the surface temperature of the inorganic fluorescent layer sheet was close to 120 ° C. On the other hand, when the temperature of the inorganic fluorescent layer adjacent to the organic light emitting cell of the lighting device according to Example 1 was measured, the surface temperature showed a low value of 80 ° C.

Example 7
Using the same material configuration as in Example 1, a prototype LED lighting device that does not have a liquid feeding mechanism and a special cooling mechanism was manufactured. In spite of only natural convection and natural heat dissipation, an inorganic fluorescent layer adjacent to the organic light emitting cell was used. The surface temperature was not so high as 100 ° C.

Comparative Example An LED lighting device having a configuration in which the fluid was removed from the LED lighting device according to Example 1 was made as an experiment. According to the LED lighting device thus configured, Ra was as low as 62, and it was found that the spectral intensity in the red region was particularly small.

The figure which shows the outline of the LED lighting apparatus which concerns on the 1st Embodiment of this invention. The characteristic view which compares and compares the fluorescence intensity of the organic fluorescent substance when it contains in the solid thin film, and when melt | dissolving in the solution. Sectional drawing which shows the LED lighting apparatus which concerns on the 2nd Embodiment of this invention. Sectional drawing which shows the LED lighting apparatus which concerns on the 3rd Embodiment of this invention. Sectional drawing which shows the light control panel used for the LED lighting apparatus which concerns on the 4th Embodiment of this invention. Sectional drawing which shows the light control panel used for the LED lighting apparatus which concerns on the 5th Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,11,21 ... LRD element, 2,12 ... Organic light emitting cell, 3,13,31 ... Inorganic yellow fluorescent layer, 4 ... Inlet, 5 ... Discharge, 6 ... Pipe, 7 ... Cooling / cooling means , 14 ... glass cell, 15 ... fluid, 41 ... matrix polymer, 42 ... inorganic yellow light emitting phosphor, 43 ... organic red light emitting phosphor.

Claims (15)

  An illumination device including a light emitting element and a light control layer for adjusting light from the light emitting element, wherein the light control layer includes a light emitting layer made of a fluid in which a phosphor is dissolved in a medium. Lighting device.   The lighting device according to claim 1, wherein the light emitting layer is a red light emitting layer made of a fluid in which a red light emitting phosphor is dissolved.   The lighting device according to claim 2, wherein the light control layer has a yellow light emitting layer adjacent to the light emitting layer.   4. The illumination device according to claim 2, wherein the red light emitting phosphor is a rare earth complex phosphor. The lighting device according to claim 4, wherein the rare earth complex phosphor is a europium complex having a structure represented by the following formula (1).

(In the formula, R ^{1 to} R ⁹ are each an alkyl group or an alkoxy group having a straight chain or branched structure having 20 or less carbon atoms, a phenyl group, a biphenyl group, a naphthyl group, a heterocyclic group, and a substituent thereof. Except when selected from the group consisting of a hydrogen atom and a deuterium atom, and R ¹ -R ⁶ are all the same.) The lighting device according to claim 4, wherein the rare earth complex is a europium complex having a structure represented by the following formula (2).

(In the formula, R ^{1 to} R ⁷ are each an alkyl group or an alkoxy group having a straight chain or branched structure having 20 or less carbon atoms, a phenyl group, a biphenyl group, a naphthyl group, a heterocyclic group, and a substituent thereof. (N is an integer of 2 or more and 20 or less, except when selected from the group consisting of a hydrogen atom and a deuterium atom, and R ¹ -R ⁴ are all the same.)   A light-emitting element, a light-control layer having a light-emitting layer containing a fluid obtained by dissolving a phosphor in a medium in a transparent cell, and a circulation means connected to the transparent cell and circulating the fluid. A lighting device.   The lighting device according to claim 7, wherein the light emitting layer is a red light emitting layer made of a fluid in which a red light emitting phosphor is dissolved.   The lighting device according to claim 8, wherein a yellow light emitting layer is disposed on an outer wall or an inner wall of the transparent cell.   The lighting device according to claim 9, wherein a plurality of the yellow light emitting layers are arranged in a grid pattern.   The lighting device according to claim 1, wherein the medium exhibits a liquid crystal phase.   The lighting device according to claim 7, wherein the circulation unit includes a cooling unit or a heat dissipation unit.   In a lighting device including a light-emitting element and a light control layer including a first phosphor and a second phosphor, the first phosphor is phase-separated into a matrix polymer including a second phosphor. A lighting device that is dispersed.   The lighting device according to claim 13, wherein the first phosphor is a red light-emitting phosphor, and the second phosphor is a yellow light-emitting phosphor.   A light control panel comprising a red light emitting layer made of a fluid containing a red light emitting phosphor and a yellow light emitting layer disposed adjacent to the red light emitting layer.

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