JP5341154B2 - High color rendering LED lamp unit - Google Patents

Description

  The present invention relates to a high color rendering light emitting diode lamp unit, and more particularly to a high color rendering light emitting diode lamp unit in which a plurality of light emitting diode lamps using light emitting diode elements having variations in emission center wavelength are assembled.

  In the present specification, “high color rendering” means a performance that allows the color of an object to be seen in a color that is more similar to the state seen in natural light.

  Conventionally, a light emitting diode that emits light at a short wavelength such as blue (hereinafter, the light emitting diode may be referred to as LED) is excited by absorbing part or all of the light emitted from the element and the LED, and has a longer wavelength yellow. A white LED using a phosphor that emits fluorescence such as the above is known. For example, a blue LED element and a white LED made of yttrium / aluminum / garnet phosphor activated by cerium that absorbs blue light and emits yellow fluorescence that is a complementary color of blue are disclosed (Patent Document 1). See).

  However, conventionally, the spectrum obtained by color mixing has a small light component in the red region and the light emission wavelength band of the LED is narrow, so that the light intensity is low between the light emission wavelength band of the LED and the light emission wavelength band of the phosphor. Due to the presence of the wavelength band, there was a drawback of poor color rendering.

  In order to eliminate this drawback, a white LED light emitting device comprising a red LED element and a green LED element is disclosed as a phosphor emitting blue light by absorbing blue light and blue light (see Patent Document 2). .) In addition, there are a plurality of methods such as a method of obtaining white light by three types of LED elements that emit red, green, and blue colors, and a method of obtaining white light by a blue LED element and a phosphor that absorbs blue light and emits yellow light. An apparatus combining a white LED by the above method is disclosed (see Patent Document 3).

  On the other hand, as a method of increasing the light component in the red region without using a plurality of types of LED elements, compound semiconductor blue LED elements, and yttrium activated by cerium that absorbs blue light and emits yellow fluorescence. An LED in which an aluminum / garnet phosphor and a phosphor that absorbs blue light from a compound semiconductor blue LED element and emits red light is mixed is also disclosed (see Patent Document 4).

Japanese Patent No. 2927279 JP 2005-5482 A Utility Model Registration No. 3102894 JP 2003-101081 A

  However, the technique of Patent Document 1 has the disadvantages as described above, and the techniques of Patent Document 2 and Patent Document 3 use a plurality of types of LED elements, and thus are adapted to the driving voltages of various LED elements. Thus, it is necessary to add a plurality of types of voltages, and there is a drawback that the electronic circuit becomes complicated.

  Moreover, since the light emission wavelength band of LED is narrow in the technique of patent document 4, it cannot supplement the wavelength band where the light intensity between the light emission wavelength band of the existing LED and the fluorescence wavelength band from the phosphor is low. There was a disadvantage that the color rendering properties were insufficient.

  An object of the present invention is to provide an LED lamp unit having high color rendering properties and no complexity of an electronic circuit.

Even in the same type, the LED elements exist over a certain range of emission center wavelengths generated at the same operating voltage. For this reason, when using a plurality of LED elements, in order to align the characteristics of each white LED, select LED elements having the same emission center wavelength as much as possible, or elements classified by the element manufacturer for each wavelength. I use it.
On the other hand, as a method for reducing the difference in band between the LED emission wavelength band and the fluorescence wavelength band, a method of making the center wavelength of the LED element longer is also conceivable, but the chromaticity of the obtained white LED or It is difficult to change the emission center wavelength from the viewpoint of the excitation efficiency of the phosphor.
As a result of intensive studies in view of the prior art, the present inventors have found that when a plurality of LED elements are used, even when only the same kind of LED elements are used, the same kind having different emission center wavelengths is used. By using this element, the emission wavelength band is widened, and the difference in wavelength band between the emission wavelength band of the LED element and the fluorescence wavelength band from the phosphor is maintained while maintaining the emission center wavelength of the entire unit. The present invention has been completed by finding that high color rendering properties can be obtained by reduction.

The present invention for solving the above-mentioned problems is a collection of a plurality of light-emitting diode lamps capable of emitting white light by color mixing of excitation light emitted from a blue light-emitting diode element and light emitted from a phosphor that has absorbed the excitation light. It is a high color rendering light-emitting diode lamp unit, providing variation in the emission center wavelength of the excitation light of each blue light-emitting diode element, the difference between the maximum value and the minimum value of the emission center wavelength of the excitation light of each blue light-emitting diode element, It is a high color rendering light-emitting diode lamp unit characterized by being 5 nm or more and less than 20 nm.
From a phosphor that absorbs excitation light from a blue light emitting diode element and emits yellow light, a phosphor that absorbs excitation light from a blue light emitting diode element and emits red light, or a blue light emitting diode element A phosphor that absorbs the excitation light and emits green light is preferable.
The blue light emitting diode element is preferably a nitride compound semiconductor.

  The high color-rendering light-emitting diode lamp unit of the present invention intentionally uses the same kind of LED elements having different emission center wavelengths, thereby expanding the emission wavelength band while maintaining the desired emission center wavelength as a whole unit. As a result, the fluorescence wavelength band is also expanded, the difference in wavelength band between the emission wavelength band of the LED element and the fluorescence wavelength band from the phosphor is reduced, and high color rendering white can be emitted.

It is a schematic diagram which shows an example of the high color-rendering chip type white LED lamp used for this invention. It is an external view of the high color rendering white LED lamp unit of the present invention. It is a schematic diagram which shows an example of the highly color-rendering bullet-type white LED lamp used for this invention.

  Next, the present invention will be described in detail. The LED element used for this invention is a commercial item. When used in lighting devices that require a large amount of light, a plurality of the same LED elements are used. Even if the LED elements are the same type and emit light at the same operating voltage, they emit light. There is variation in the center wavelength. For example, in the case of MegaBright manufactured by Cree, InGaN-based blue LED elements having an emission center wavelength ranging from 455.0 nm to 205.0 nm from 475.0 nm are classified and lined up according to wavelength. In the present invention, a blue LED element having a variation in emission center wavelength, preferably 1 nm or more, more preferably 3 nm or more, particularly preferably 5 nm or more, even more preferably 10 nm or more, and most preferably 20 nm or more, to the emission center wavelength. A plurality of blue LED elements having variations are used.

The LED lamp unit of the present invention can emit white light having high color rendering properties by color mixing of excitation light from a plurality of blue LED elements of the same type having different emission center wavelengths and light emitted from a phosphor that has absorbed the excitation light. It is to make. Further, as the phosphor used in the present invention, a phosphor that absorbs excitation light from a blue LED element and emits yellow light, a phosphor that absorbs excitation light from a blue LED element and emits red light, Alternatively, a phosphor that absorbs excitation light from a blue LED element and emits green light is desirable. As the blue LED element, it is desirable to use a nitride-based semiconductor, for example, InGaN, AlGaN, AlGaInNbN or the like. Examples of phosphors that emit yellow light include YAG-based, phosphate-based, silicate-based, aluminate-based, television-based, and strontium-based phosphors. Examples of the phosphor that emits red light include CaAlSiN ₃ , Y ₂ O ₃ : Eu ³⁺ in which Eu is dissolved. Examples of phosphors that emit green light include β-sialon crystals containing ZnSiO ₄ and Eu.

  In the present invention, as apparent from the test examples described later, the light emission wavelength band is expanded by intentionally using the same kind of LED elements having different emission center wavelengths, and as a result, the fluorescence wavelength band is also expanded. The difference in wavelength band between the emission wavelength band and the fluorescence wavelength band from the phosphor is reduced, and a high color rendering white LED lamp unit is obtained.

  It is as follows if a specific example is shown and described. FIG. 1 is an example of a schematic cross-sectional view of a highly color-rendering chip type white LED lamp of the present invention. Two lead wires (102, 103) are fixed to a white substrate (101) having a high visible light reflectivity, and one end of each of these lead wires is located at the center of the substrate, and the other end is external. It is an electrode that is soldered to the electric board when mounted.

In one of the lead wires, a semiconductor blue LED element (104) is fixed to one end of the lead wire so as to be a central portion of the substrate. The lower electrode (107) of the blue LED element and the lead wire (103) therebelow are electrically connected by a conductive paste, and the upper electrode (106) and the other lead wire (102) are thin gold wires. They are electrically connected by (105).
On the substrate (101), a wall member (108) having a shape with a hole in the center is fixed. A hole for mounting the blue LED element (104) is provided in the central portion of the wall surface member (108), and the portion facing the center is an inclined surface. This slope is a reflection surface for extracting light forward, and the curved surface shape of the slope is determined in consideration of the light reflection direction.

  Further, the reflecting surface is a member having a high visible light reflectance and having at least white or metallic luster. In the example of FIG. 1, the hole in the center of the wall member is concave when it is fixed to the substrate, but here the blue LED element (104) is sealed, so that the wall member (108) is fluorescent. It is filled with a transparent resin (109) in which the body is dispersed. In FIG. 1, the upper surface of the transparent resin (109) is exemplified as a flat shape, but may have a convex shape upward.

  The chip-type LED lamps illustrated in FIG. 1 can be arranged concentrically as illustrated in FIG. 2 to manufacture a white LED lamp unit. By configuring in this way, the same kind of LED elements having different emission center wavelengths are intentionally used to broaden the emission wavelength band of the LED elements, and the emission wavelength band of the LED elements and the fluorescence wavelength band of the phosphor A white LED having a high color rendering property can be obtained by reducing the drop in the wavelength band between them. It should be noted that this chip type LED lamp can be used in an appropriate number such as several, several tens or several hundreds depending on the desired light quantity. In this example, the chip-type LED lamp is mounted concentrically, but it can be mounted in various shapes such as a square, a rectangle, and a trapezoid depending on the purpose of use.

  Moreover, the bullet-type LED lamp shown in FIG. 3 can also be used for the high color rendering LED lamp unit of the present invention. The bullet-type white LED lamp has two lead wires (302, 303), one of which (302) has a recess as shown, and a blue LED element (304) is placed thereon. The lower electrode (307) of the blue LED element and the bottom surface of the lead wire (302) are electrically connected by a conductive paste, and the upper electrode (306) of the blue LED element and the other lead wire (303) are gold. It is electrically connected by a thin wire (305). The transparent first resin (308) in which the phosphor is dispersed covers the entire blue LED element.

  The tip of the lead wire (302) including the concave portion, the blue LED element (304), and the first transparent resin (308) in which the phosphor is dispersed are sealed with a transparent second resin (310). The whole of the transparent second resin (310) has a substantially cylindrical shape, and the tip thereof is a lens-shaped curved surface.

  The high color rendering LED lamp unit in which the bullet-type white LED lamp configured as described above is arranged is similar to the case in which the chip-type LED lamp is arranged, and the emission wavelength band of the LED element and the fluorescence wavelength band from the phosphor. The drop in the wavelength band between the two can be reduced.

  EXAMPLES Next, although an Example is shown and this invention is demonstrated further in detail, this invention is not limited to a following example.

  Twenty-five chip type white LED lamps were mounted on a concentric circle to produce a high color rendering LED lamp unit as shown in FIG. For each chip-type white LED lamp, blue LED elements having various emission center wavelengths ranging from 455.0 to 474.9 nm and 20 nm were used.

  In Example 2, a high color rendering LED lamp unit was prepared in the same manner as in Example 1 except that blue LED elements having various emission center wavelengths ranging from 462.5 to 467.5 nm in Example 1 were used. Produced.

  Example 3 is the same as in Example 1, except that blue LED elements having various emission center wavelengths ranging from 33.5 nm to 466.5 nm in Example 1 were used. Produced.

  Example 4 is the same as in Example 1, except that blue LED elements having various emission center wavelengths ranging from 14.5 nm to 464.5 nm to 14.5 nm were used. Produced.

(Comparative Example 1)
A high color rendering light emitting diode lamp unit was produced in the same manner as in Example 1 except that 25 samples having an emission center wavelength of 465.0 nm were selected and used.

(Test Example 1)
About each high color rendering light emitting diode lamp unit obtained above, LED was set to the integrating sphere, the emission spectrum was measured, and the average color rendering index and chromaticity coordinates were measured from the spectrum. The results are shown in Table 1.

It was found that the average color rendering index increases particularly greatly when the difference between the maximum value and the minimum value of the emission center wavelength is 5 nm or more as in the white LED lamp unit of the present invention. Furthermore, it has been recognized that the chromaticity coordinates of the white LED lamp unit of the present invention are hardly changed, and have little influence on the chromaticity.
In addition, the same test was done also about the case where a bullet-type LED lamp was used, but the same result was obtained. Therefore, it has been found that the high color rendering light emitting diode lamp unit of the present invention has a performance far superior to that of the prior art.

    The highly color-rendering light-emitting diode lamp unit of the present invention described in detail above is useful in all industrial fields using white illumination.

101 Substrate 102, 103, 302, 303 Lead wire 104, 304 Blue LED element 105, 305 Gold wire 106, 306 Blue LED element upper electrode 107, 307 Blue LED element lower electrode 108, 308 Wall member 109, 309 Transparent First resin 310 Transparent second resin 220 Chip type white LED lamp

Claims (3)

  This is a high color rendering light-emitting diode lamp unit in which a plurality of light-emitting diode lamps capable of emitting white light by color mixing of excitation light emitted from a blue light-emitting diode element and light emitted from a phosphor that has absorbed the excitation light are assembled. The emission center wavelength of the excitation light of each blue light emitting diode element is varied, and the difference between the maximum value and the minimum value of the emission center wavelength of excitation light of each blue light emitting diode element is 5 nm or more and less than 20 nm. High color rendering LED lamp unit.   From a phosphor that absorbs excitation light from a blue light emitting diode element and emits yellow light, a phosphor that absorbs excitation light from a blue light emitting diode element and emits red light, or a blue light emitting diode element The high color-rendering light-emitting diode lamp unit according to claim 1, which is a phosphor that absorbs the excitation light and emits green light.   The high color rendering LED lamp unit according to claim 1 or 2, wherein the blue LED element is a nitride compound semiconductor.

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