JP2016170294A - Wavelength control filter, and light emitting device and illumination device having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength control filter with high color rendering capability and light resistance for use with light emitting devices.SOLUTION: A wavelength control filter 1 consists of a base material 31 made of a translucent resin, and a pigment 32 for controlling wavelength of light added to the base material 31, and comprises a plurality of types of resin layers 3A, 3B with different concentration of the pigment 32 with respect to the base material 31. With such a configuration, the resin layer 3A containing the pigment 32 provides high color rendering property, and forming the resin layers 3B containing no pigment 32 to increase the thickness of the entire wavelength control filter 1 while making the pigment concentration of the resin layer 3A relatively higher minimizes reduction in wavelength controlling capability of the pigment 32 and increases light resistance.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a wavelength control filter that controls the wavelength of light emitted from a light emitting diode (LED), a light emitting device using the same, and an illumination device.

  A light emitting diode (hereinafter referred to as an LED) is capable of emitting light with high power and high luminance and has a long lifetime, and is therefore used as a light source for a lighting device that replaces an incandescent lamp or a fluorescent lamp. In addition, there is a so-called white LED in which blue light emitted from a blue LED is applied to a phosphor to output yellow light, and white light is generated by mixing blue light and yellow light. White LEDs are excellent in luminous intensity and luminous efficiency, and lighting devices using them are used for lighting fixtures that diffuse light such as ceiling lights and base lights, and lighting fixtures that collect light such as downlights and spotlights. Has been.

  However, since the general white LED as described above has low color rendering properties, it is not suitable for lighting fixtures that illuminate food, clothing, and the like. Then, the illuminating device which provided the filter layer containing the visible light selective absorption material (henceforth pigment | dye) which has an absorption peak in a wavelength range of 575-600 nm in the front surface of a LED light source is known (for example, patent document 1). reference). According to the invention described in Patent Document 1, the filter layer reduces the intensity of the illumination light in the wavelength region of 575 to 600 nm to reduce the yellow light component. As a result, the appearance of red is good and the color rendering properties of illumination light can be enhanced.

JP 2010-267571 A

  By the way, in the filter layer described above, the pigment is uniformly dispersed with respect to the translucent resin that is the base material of the filter layer. When comparing filter layers having the same wavelength absorption amount, the thickness of the filter layer is If it is thick, the pigment concentration is set low, and if the filter layer is thin, the pigment concentration is set high. However, in the filter layer as described above, the wavelength control function tends to decrease more rapidly as the dye base material concentration is lower. For this reason, for example, when a structural member such as a protective cover of an LED light source is used as a filter, the filter needs to have a certain thickness or more, while the concentration of the pigment is lowered and the light resistance of the filter is lowered. There is a fear. In addition, the filter layer as described above tends to decrease in the wavelength control function of the dye as the thickness decreases. Therefore, when the filter layer having a high dye concentration is formed in a thin sheet so that it can be attached to a protective cover or the like, the dye concentration can be set high, but the light resistance of the filter may be reduced because the thickness is thin. There is.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a wavelength control filter that can achieve high color rendering properties and has high light resistance, and a light emitting device and a lighting device using the same.

  In order to solve the above-described problems, the present invention provides a wavelength control filter having a light-transmitting resin and a pigment that is added to the light-transmitting resin to control the wavelength of light, and A plurality of types of resin layers having different dye concentrations are laminated.

  According to the present invention, high color rendering properties can be obtained by forming the wavelength control filter with a resin layer containing a pigment. In addition, among a plurality of types of resin layers having different dye concentrations, the dye concentration of a certain resin layer is relatively high, while a resin having a low dye concentration or a layer containing no resin is laminated to By giving the thickness, it is possible to suppress a decrease in the wavelength control function of the dye and to improve light resistance.

1 is an exploded perspective view of a light emitting device according to an embodiment of the present invention. The sectional side view of the LED light source used for the light-emitting device. The figure which shows the emission spectrum of the LED light source. The perspective view and partial side view of the wavelength control filter (Example 1) used for the light-emitting device. The figure which shows structural formula of the tetraaza porphyrin compound used for the wavelength control part of the said light-emitting device. The figure which shows the light absorption spectrum of the tetraaza porphyrin compound used for a wavelength control part. The figure which shows the spectrum of the emitted light of the said light-emitting device. The figure for demonstrating the relationship between the pigment density | concentration of the said wavelength control filter, and light resistance. The perspective view and partial side view of a general wavelength control filter (comparative example). The perspective view and partial side view of the wavelength control filter (Example 2) used for the said light-emitting device. The perspective view and partial side view of the wavelength control filter (Example 3) used for the said light-emitting device. The perspective view and partial side view of the wavelength control filter (Example 4) used for the said light-emitting device. The figure for demonstrating the relationship between the thickness of the said wavelength control filter, and light resistance. The perspective view and partial side view of the wavelength control filter (modification) used for the said light-emitting device. The perspective view of the illuminating device using the said light-emitting device.

  A light emitting device according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the light emitting device 1 of this embodiment includes an LED light source 2 and a wavelength control filter 3 provided on the front surface of the LED light source 2. The front surface of the LED light source 2 refers to a surface facing the direction in which light is emitted from the LED light source 2.

  As the LED light source 2, an LED module having a light emitting unit 4 on one surface is used, and this LED module is mounted on a substrate 5. The LED light source 2 is, for example, an LED in which a GaN-based blue LED chip that emits blue light with an emission peak wavelength of 460 nm is coated with a YAG-based yellow phosphor, and white light is emitted by mixed light of blue light and yellow light. Modules are used. When the LED light source 2 is a single unit as in this embodiment, a general-purpose chip-on-board (COB) type LED package is preferably used.

  Specifically, as shown in FIG. 2, the LED light source 2 includes a substrate 20 having a rectangular cross section made of aluminum or ceramic, an LED chip 21 mounted on the substrate 20, and a bank 22 surrounding the LED chip 21. And a sealing member 23 filled in the bank 22. In the example shown in the figure, a configuration using two LED chips 21 is shown, but the present invention is not limited to this. For example, a silicone resin or the like is used for the sealing member 23 and contains a phosphor 24 that converts the wavelength of light emitted from the LED chip 21. A cathode electrode 25 and an anode electrode 26 are respectively provided on the upper surface of the substrate 20, and the cathode electrode 25 and the anode electrode 26 are connected to each electrode terminal of the LED chip 21 by wires 27.

  The inner periphery of the bank 22 has a circular shape when viewed from above, and the surface of the sealing member 23 exposed from the opening of the bank 22 is filled with the sealing member 23 containing the phosphor 24 in the periphery. Becomes the light emitting section 4 that emits light.

  In the LED light source 2 of the present embodiment, for example, as shown in FIG. 3, the LED chip 21 emits light having a light emission peak wavelength in the vicinity of a wavelength of 460 nm, and the phosphor 24 has a light emission peak wavelength in the vicinity of a wavelength of 610 nm. The light it has is emitted. The LED light source 2 can emit white light obtained by mixing these lights.

  As shown in FIG. 4, the wavelength control filter 3 includes a base material 31 made of a translucent resin, and a dye 32 that is added to the base material 31 and controls the wavelength of light (see the enlarged view of FIG. 4). ). The wavelength control filter 3 includes a plurality of types of resin layers having different concentrations of the pigment 32 with respect to the base material 31. The plurality of types of resin layers having different concentrations of the pigment 32 referred to here include a resin layer not containing the pigment 32. In the wavelength control filter 3, a resin layer having a relatively high concentration of the dye 32 is sandwiched between resin layers having a relatively low concentration of the dye 32 or not containing the dye 32.

  Hereinafter, the configuration example illustrated in FIG. 4 is referred to as a wavelength control filter 3i according to the first embodiment. In the wavelength control filter 3i according to Example 1, the dye 32 was added at a double concentration (dye concentration 2x) as compared with a wavelength control filter 3r (dye concentration x, see FIG. 9) of a comparative example described later. It consists of a resin layer 3A and a resin layer 3B to which no pigment 32 is added. In addition, the resin layer 3 </ b> A having a relatively high concentration of the dye 32 is sandwiched between two resin layers 3 </ b> B that do not contain the dye 32. The wavelength control filter 3i according to Example 1 is formed as a plate having a thickness of 30 mm square and a thickness of 2 mm, the thickness of the resin layer 3A having a dye concentration of 2x is 1 mm, and the thickness of the resin layer 3B not including the dye 32 is 0.00. It is 5 mm.

  The base material 31 is made of any resin material or glass having translucency. For example, examples of the optically transparent material include thermoplastic resins such as polymethyl methacrylate, polycarbonate, cyclic polyolefin, cyclic polyolefin copolymer, and polymethylpentene. Examples of the milky white translucent material include thermoplastic resins such as polyethylene and polypropylene. Furthermore, after adding a crosslinking component to a methacrylic acid resin or a silicone resin, a thermosetting resin that is cured by applying heat or energy such as an electron beam or ultraviolet rays may be used. In addition, an ultraviolet absorber, a light stabilizer, an antioxidant, a hydrolysis inhibitor, and the like may be appropriately added to the base material 31 with respect to the resin material that is the base material, depending on the application. In the present embodiment, a flat plate-shaped member is illustrated as the wavelength control filter 3, but a light distribution control member formed and processed into a shape that diffuses or condenses light emitted from the LED light source. Also good.

  The dye 32 is a compound having a property of selectively absorbing light of a specific wavelength. Examples thereof include dyes mainly composed of organic compounds such as tetraazaporphyrin, tetraphenylporphyrin, octaethylporphyrin, phthalocyanine, cyanine, pyromethene, squarylium, xanthene, dioxane and oxonol. In particular, a tetraazaporphyrin compound as shown in FIG. 5 is preferably used because it has high fastness to light irradiation from a light source. In the figure, M represents an element serving as a central metal, and R1 to R8 represent substituents.

  In the present embodiment, as the dye 32, a dye having a maximum absorption wavelength in the wavelength range of 450 to 650 nm is used. In particular, tetraazaporphyrin, which is a dye having a maximum absorption wavelength in the wavelength range of 570 to 590 nm, is preferably used. FIG. 6 shows the absorption of a wavelength control filter 3 prepared by adding a tetraazaporphyrin compound having copper as a central metal to an acrylic resin (VH001 (manufactured by Mitsubishi Rayon Co., Ltd.)) as a base material 31 at a concentration of 30 ppm. The characteristic was measured with a self-recording spectrophotometer (U4100, manufactured by Hitachi High-Technology Corporation).

  In the LED light source 2, the emitted light from the LED light source 2 having the light emission characteristics shown in FIG. 3 is transmitted through the wavelength control unit 6 containing the pigment having the absorption characteristics shown in FIG. Is emitted. FIG. 7 shows the spectral characteristics of white light emitted from the light emitting device 1. In addition, the spectral spectrum of the figure was measured by the instantaneous multiphotometry system (MCPD-7700 (made by Otsuka Electronics)). Since the white light emitted from the LED light source 2 has a wavelength in the range of 570 to 590 nm, the yellow light component is reduced and high color rendering can be obtained.

Here, the influence of the dye concentration on the heat resistance and light resistance of the wavelength control filter will be described with reference to FIG. Specifically, each of the prepared samples was put into a heat and light resistance test tank, and a heat and light resistance test for evaluating based on the maintenance rate of the main absorption peak before and after the test was performed. The outline of the heat and light resistance test is as follows.
・ Test tank: Metal weather testing machine made by Daipura Wintes Co., Ltd. ・ Test conditions: 75 ° C
・ Spectrophotometer: U4100 manufactured by Hitachi High-Technology Corporation
Derivation method of residual rate: Measure the total light transmittance of the test sample with a spectrophotometer, and determine the initial transmittance (T0) and the transmittance after the test (T1) of the maximum absorption wavelength (595 nm in this case) of the dye. The residual ratio was calculated from the following calculation formula (1).
(Equation 1)
Residual rate = (TB−T1)) / (TB−T0) × 100 (1)
Where TB is the transmittance of the substrate

  FIG. 8 shows the results of a heat and light resistance test of the wavelength control filter 3 when the filter thickness is the same and the dye concentration is changed 1 to 3 times. From these results, it was shown that when the dye concentration is different, the one with the higher dye concentration has higher heat resistance and light resistance.

  FIG. 9 shows a configuration example of the wavelength control filter 3r according to the comparative example. The wavelength control filter 3r according to this comparative example has the same outer dimensions as the resin layer 3A (the dye concentration 2x, see FIG. 4) of the wavelength control filter 3i of the first embodiment, but the dye concentration is half (the dye concentration). x). As described above, when the pigment 32 is uniformly dispersed in the base material 31, the pigment concentration is lowered, so that the wavelength control function is likely to be lowered, and the light resistance of the filter may be lowered.

  On the other hand, according to the wavelength control filter 3i according to the first embodiment, the resin layer 3A has a high pigment concentration, while the resin layer 3B not containing the pigment 32 is provided, and the total thickness of the filter, The overall pigment content is the same as that of the wavelength control filter 3r according to the comparative example. Therefore, according to the wavelength control filter 3i according to the first embodiment, having the same wavelength control performance as the wavelength control filter 3r according to the comparative example, the light resistance of the filter is achieved while realizing high color rendering properties of illumination light. Can be improved.

  FIG. 10 illustrates a configuration example of the wavelength control filter 3ii according to the second embodiment. The wavelength control filter 3ii according to Example 2 is a dye 32 having a density (dye density 2.88x) that is 2.88 times that of the comparative wavelength control filter 3r (referred to as dye density x, see FIG. 9). The resin layer 3C to which is added, and the resin layer 3B to which the pigment 32 is not added. In addition, the frontal dimension of the resin layer (resin layer 3C in this example) having a relatively high concentration of the dye 32 is smaller than the filter dimension, and the periphery of the resin layer 3C has a relatively low concentration of the dye 32 or It is covered with a resin layer that does not contain the pigment 32 (in this example, the resin layer 3B). Specifically, the resin layer 3C is formed in a layer shape of 25 mm square and 1 mm in thickness, and a 2.5 mm width resin layer 3B that does not include the pigment 32 covers the four sides of the resin layer 3C. According to the wavelength control filter 3ii according to Example 2, since the resin layer 3C is not exposed to the outside, it is considered that the pigment 32 does not come into contact with moisture or oxygen in the outside air. Therefore, the light resistance of the filter can be particularly improved while having the same wavelength control performance as the wavelength control filter 3r according to the comparative example.

  FIG. 11 illustrates a configuration example of the wavelength control filter 3iii according to the third embodiment. The wavelength control filter 3iii according to Example 3 has a dye 32 with a concentration (dye concentration of 0.2x) 0.2 times that of the comparative wavelength control filter 3r (referred to as dye concentration x, see FIG. 9). Is added to the resin layer 3D, and the resin layer 3E to which the pigment 32 is added at a density 1.8 times (pigment concentration 1.8x). The resin layer 3E having a relatively high concentration of the dye 32 is sandwiched between two resin layers 3D having a relatively low concentration of the dye 32.

  FIG. 12 illustrates a configuration example of the wavelength control filter 3iv according to the fourth embodiment. The wavelength control filter 3iv according to Example 4 is a dye 32 having a density (dye density 0.9x) 0.9 times that of the comparative wavelength control filter 3r (dye density x, see FIG. 9). Is added to the resin layer 3F, the resin layer 3G to which the dye 32 is added at 1.2 times the density (dye density 1.2x), and the dye 32 at the 0.7 times density (the dye density 0.7x). And a resin layer 3H to which is added. The resin layer 3G having a relatively high concentration of the dye 32 is sandwiched between the two resin layers 3F and H having a relatively low concentration of the dye 32.

  Table 1 below shows the results of a light resistance test performed on the above-described wavelength control filters 3i to 3iv and 3r according to Examples 1 to 4 and Comparative Example. The test was performed in the same manner as the heat and light resistance test and procedure described with reference to FIG. 8, and the light resistance was evaluated by the number of days to reach the remaining rate of 80%.

  From the results in Table 1, it was shown that in Examples 1 to 4, higher light resistance than that of the comparative example was obtained. Further, as in Example 1 and Example 3, the resin layers 3A and 3E in which the concentration of the pigment 32 is relatively high are resin layers 2B and 3D in which the concentration of the pigment 32 is relatively low or does not contain the pigment 32. It was shown that particularly high light resistance can be obtained in the sandwiched configuration. Moreover, in Example 2, since the density | concentration of the pigment | dye 32 of the resin layer 3C was the highest and it was covered to the periphery by the resin layer 2B which does not contain the pigment | dye 32, it was shown that extremely high light resistance is obtained. .

  Thus, according to the wavelength control filter 1 of this embodiment, high color rendering properties can be obtained by the resin layer 3 </ b> A containing the pigment 32. Moreover, while making the pigment | dye density | concentration of the resin layer 3A relatively high, the fall of the wavelength control function of the pigment | dye 32 is suppressed by giving the thickness of the whole wavelength control filter 1 by the resin layer 3B which does not contain the pigment | dye 32. , Light resistance can be enhanced.

  The influence of the filter thickness on the heat resistance and light resistance of the wavelength control filter will be described with reference to FIG. Also in this case, the prepared sample was put into a heat and light resistance test tank, and a heat and light resistance test for evaluating based on the maintenance rate of the main absorption peak before and after the test was performed. The outline of the heat and light resistance test is the same as the procedure described in FIG. FIG. 13 shows the results of a heat and light resistance test of the wavelength control filter 3 when the dye concentration is the same and the filter thickness is changed by 1 or 2 times. From these results, it was shown that when the filter thickness is different, the thicker filter thickness is higher in heat resistance and light resistance.

  In any of the embodiments described above, the thickness of the resin layers 3A, 3C, 3E, and 3G in which the concentration of the pigment 32 is relatively high among the plurality of types of resin layers is relatively low or contained. The resin layers 3B, 3D, 3F, and 3H that are not formed are formed to be thicker. That is, higher light resistance can be obtained by increasing the thickness of the resin layer having a high concentration of the dye 32 than the resin layer having a low concentration of the dye 32.

  FIG. 14 shows a wavelength control filter 3m according to a modification of the above embodiment. The wavelength control filter 3m includes a resin layer 3I having a relatively high concentration of the dye 32 and a resin layer 3B that does not contain the dye 32. The resin layer 3I having a relatively high concentration of the pigment 32 is formed in a strip shape on the same plane, and a resin layer 3B not containing the pigment 32 is filled between the resin layers 3I.

  As shown in FIG. 13, the light resistance of the wavelength control filter increases as the dye concentration increases and the filter thickness increases. However, in order to realize the transmittance as shown in FIG. 6, the pigment content in the entire filter needs to be constant. Therefore, as shown in FIG. 14, by making the resin layer 3I into a strip shape, the pigment concentration is increased and the layer thickness is increased, while a layer not containing the pigment 32 is interposed between the resin layers 3I. Thus, a desired transmittance can be realized. The front view shape of the wavelength control filter 3 is not limited to the illustrated square, and may be a circle, a rectangle, or an arbitrary polygon.

  The light emitting device 1 using the wavelength control filter 3 of the present embodiment is applied to, for example, an illumination device 10 as shown in FIG. Here, a configuration in which an LED light source (not shown) is built in a spherical instrument housing 11 and a circular wavelength control filter 3 is attached to an opening provided in the instrument housing 11 is shown. According to this illuminating device 10, by using the wavelength control filter 3 with high light resistance, it is possible to irradiate illumination light with high color rendering properties stably over a long period of time.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, the wavelength control filter 3 according to the above example has a structure in which two or three types of resin layers having different dye concentrations are laminated, but the resin layer has three or more types, or four or more layers. A laminated structure may be used. Moreover, you may affix the wavelength control filter 3 on a separate translucent member. In this case, you may provide in a limited part in the part facing the light emission part 4 of the LED light source 2 among separate translucent members. Further, as shown in FIG. 10 (Example 2), the resin layer 3 </ b> C having a relatively high concentration of the dye 32 may be provided in a limited manner in a portion facing the light emitting unit 4 of the LED light source 2.

DESCRIPTION OF SYMBOLS 1 Light-emitting device 10 Illuminating device 2 LED light source 3 Wavelength control filter 3A-3I Resin layer 31 Base material (translucent resin)
32 Dye

Claims (9)

A wavelength control filter comprising a translucent resin and a dye that is added to the translucent resin to control the wavelength of light,
A wavelength control filter, wherein a plurality of types of resin layers having different dye concentrations with respect to the translucent resin are laminated. The plurality of types of resin layers include a resin layer not containing the pigment,
The wavelength control filter, wherein the resin layer having a relatively high concentration of the dye is sandwiched between resin layers having a relatively low concentration of the dye or not containing the dye.   The wavelength control according to claim 2, wherein a peripheral edge of the resin layer having a relatively high concentration of the dye is covered with a resin layer having a relatively low concentration of the dye or not containing the dye. filter.   Of the plurality of types of resin layers, the thickness of the resin layer having a relatively high concentration of the dye is relatively low or thicker than the thickness of the resin layer not containing the dye. The wavelength control filter according to claim 2 or 3, wherein:   The wavelength control filter according to claim 1, wherein the dye has a maximum absorption wavelength in a wavelength range of 450 to 600 nm.   The wavelength control filter according to claim 1, wherein the dye is a tetraazaporphyrin compound.   The wavelength control filter according to claim 6, wherein a central metal of the tetraazaporphyrin compound is copper.   A light emitting device comprising: the wavelength control filter according to claim 1; and an LED light source that emits light toward the wavelength control filter.   The illuminating device using the light-emitting device of Claim 8.