JP2009032524A - LED lighting device - Google Patents

Abstract

An LED lighting device capable of improving color reproducibility and color mixing with a simple configuration without performing feedback control is provided.
SOLUTION: At an intersection of two chromaticity points W1 and W2 defined on a black body locus BL in an xy chromaticity diagram and two tangent lines contacting the black body locus BL at each of the two chromaticity points W1 and W2. A light emitting device 1a that emits the colors of the chromaticity points R1, B1, and G1 of the respective vertices of a triangle that is a polygon that includes a triangle that connects the three chromaticity points W1, W2, and C with the chromaticity point C that is positioned. , 1b, 1c. Each of the light emitting devices 1a, 1b, and 1c includes blue LED chips 11a, 11b, and 11c, and protective covers (protecting portions) 13a, 13b, and 13c formed of a translucent material. The protective cover 13a contains only red phosphor, the protective cover 13b contains only green phosphor, and the protective cover 13c contains only light diffusing material.
[Selection] Figure 1

Description

  The present invention relates to an LED lighting device including a plurality of types of light emitting devices having different emission colors.

  Conventionally, LED lighting devices have been proposed in which a plurality of types of light emitting devices having different emission colors are mounted on the same substrate to obtain mixed color light having a desired color temperature (see, for example, Patent Documents 1 and 2). .

  Here, for example, as shown in FIG. 4, the LED illumination device described in Patent Document 1 has two color temperatures on the black body locus BL in the xy chromaticity diagram of the XYZ display system. A first light emitting device (main light source) set at a chromaticity point (hereinafter referred to as a white point) W between the chromaticity points Wmin and Wmax, a white point W, and a chromaticity point Wmin having a low color temperature. A second light-emitting device (first auxiliary light source) having a light emission peak wavelength in the vicinity of a point L1 that intersects the spectrum locus SL when the connecting straight line is extended in the direction of Wmin, a white point W, and a chromaticity point having a high color temperature A third light-emitting device (second auxiliary light source) having a light emission peak wavelength in the vicinity of a point S1 that intersects with the spectral locus SL when a straight line connecting Wmax is extended in the Wmax direction; It is possible to obtain a color temperature different from that of the main light source. , Moreover, it can be corrected color rendering. Here, the first light emitting device emits broad yellow light when excited by an InGaN-based blue LED chip having a light emission peak wavelength in a wavelength region of 450 to 460 nm and blue light emitted from the blue LED chip. The second light emitting device is composed of an AlINGAP-based orange LED chip having a light emission peak wavelength at 590 nm, and is composed of a white LED that obtains white light in combination with a YAG phosphor. Is configured using a blue LED chip having an emission peak wavelength in a wavelength range of 470 to 480 nm. The LED lighting device described in Patent Document 1 is particularly suitable for a shadowless lamp, a living room lamp, a makeup lamp, and the like.

The LED illumination device described in Patent Document 2 includes, for example, a light emitting device 110 using only a blue LED chip, a light emitting device 111 having a blue LED chip and a green phosphor, as shown in FIG. A light emitting device 112 having a blue LED chip and a red phosphor, a light emitting device 113 having a blue LED chip and a yellow phosphor, a light emitting device 114 using only a green LED chip, and a light output of each of the light emitting devices 110 to 114 And a control device 120 capable of adjusting the above.
JP 03/019072 (page 4, line 45 to page 5, line 8, page 5, line 24 to line 49, page 8, line 15 to line 44, and FIGS. 5, 7) JP 2007-122950 A (paragraphs [0018] to [0027] and FIGS. 1 to 3)

  By the way, in the LED lighting device disclosed in Patent Document 1, since the LED chip having a different emission peak wavelength is used for each light emitting device, the initial characteristics and the time-varying characteristics of the LED chip are different, and the ambient environment and the passage of time. This causes color misregistration. Here, in order to improve color reproducibility, a plurality of light detecting elements for detecting the light output of each light emitting device and a control circuit for feedback controlling the amount of current supplied to each LED chip of each light emitting device are provided. However, there is a problem that the cost becomes high.

  Also, in the LED illumination device having the configuration shown in FIG. 5 disclosed in Patent Document 2, since the blue LED chip and the green LED chip having different emission peak wavelengths are used as the LED chip, the initial characteristics of the LED chip are used. Also, the time-varying characteristics are different, and color misregistration occurs due to the surrounding environment and the passage of time. Further, if three types of light emitting devices 110 to 112 among the above five types of light emitting devices 110 to 114 are used, only the blue LED chip can be used as the LED chip, but the light emitting device 110 using only the blue LED chip. Is stronger than the directivity of the other light emitting devices 111 and 112, and the blue emission color becomes conspicuous, and the color mixing property is low.

  The present invention has been made in view of the above-described reasons, and an object thereof is to provide an LED lighting device capable of improving color reproducibility and color mixing with a simple configuration without performing feedback control. .

  The invention of claim 1 is an LED illumination device including a plurality of types of light emitting devices having different emission colors, and is defined on a black body locus in an xy chromaticity diagram of an XYZ display system based on desired mixed color light. Each vertex of a polygon containing a triangle connecting three chromaticity points, one chromaticity point and a chromaticity point located at the intersection of two tangents that touch the blackbody locus at each of the two chromaticity points A plurality of types of light emitting devices that emit light of a color point corresponding to the color point, and the plurality of types of light emitting devices include a blue LED chip and a protective portion that protects the blue LED chip made of a translucent material. The light emitting device that emits the color of the chromaticity point corresponding to one of the vertices of the polygon includes a diffusing material that diffuses the light emitted from the blue LED chip in the protection unit. , The chromaticity point corresponding to the other vertex of the polygon Emits light emitting device, the protection unit, characterized in that are allowed to contain a fluorescent substance which emits the color of the chromaticity point corresponding to the vertex is excited by the light emitted from the blue LED chip.

  According to the present invention, the two chromaticity points defined on the black body locus in the xy chromaticity diagram of the XYZ display system based on the desired mixed color light, and 2 in contact with the black body locus at each of the two chromaticity points. A plurality of types of light emitting devices that emit colors of chromaticity points corresponding to respective vertices of a polygon that includes a triangle connecting three chromaticity points with a chromaticity point located at the intersection of two tangent lines, The plurality of types of light emitting devices have a blue LED chip and a protection part that protects the blue LED chip made of a translucent material, and have a chromaticity point corresponding to one vertex of each vertex of the polygon. The light emitting device that emits color includes a diffusing material that diffuses the light emitted from the blue LED chip in the protection unit, and emits light of a color point corresponding to the other vertex of the polygon. The device is radiated from the blue LED chip to the protective part. A phosphor that is excited by light and emits the color of the chromaticity point corresponding to the apex is contained, so that color misregistration due to the ambient environment and time can be suppressed, and all the light emitting devices are simply turned on. Therefore, the circuit configuration for lighting is simple, and color reproducibility and color mixing can be improved with a simple configuration without performing feedback control.

  According to a second aspect of the present invention, in the first aspect of the invention, the polygon is a triangle, and as the light emitting device, a blue light emitting device in which the protective portion contains only a diffusing material, and the protective portion is the A red light-emitting device containing only a red phosphor emitting red light as a phosphor, and a green light-emitting device containing only a green phosphor whose green light is emitted as the phosphor by the protective unit; It is characterized by having.

  According to the present invention, part of the green light emitted from the green phosphor can be suppressed from being secondarily absorbed by the red phosphor and converted into red light, and the luminous efficiency of the phosphor can be improved. Can be planned.

  According to the first aspect of the invention, there is an effect that it is possible to improve color reproducibility and color mixing with a simple configuration without performing feedback control.

  The LED illuminating device of the present embodiment includes two chromaticity points W1 and W2 defined on the black body locus BL in the xy chromaticity diagram of the XYZ display system shown in FIG. A polygon containing a triangle connecting the three chromaticity points W1, W2, and C with the chromaticity point C located at the intersection of two tangents that are in contact with the black body locus BL at each of the two chromaticity points W1 and W2. (In this embodiment, a plurality of types (in this embodiment, light emitting) the colors of chromaticity points (in this embodiment, chromaticity points R1, B1, and G1) corresponding to the vertices of each of the vertices. Three types of light emitting devices 1a, 1b, and 1c (see FIG. 1A) are provided. FIG. 1B also shows a series of color matching temperature lines given by a straight line intersecting the black body locus BL.

  In the LED illumination device of the present embodiment, the above-described light emitting device 1a constitutes a red light emitting device (red light source) that emits a red color indicated by the chromaticity point R1 in the xy chromaticity diagram, and the light emitting device. 1b constitutes a green light-emitting device (green light source) that emits green light indicated by a chromaticity point G1 in the xy chromaticity diagram, and the light-emitting device 1c has a chromaticity point B1 in the xy chromaticity diagram. The blue light emitting device (blue light source) that emits the blue light shown in the figure is configured, and the color within the range of a triangle formed by connecting the chromaticity points R1, B1, and G1 with a broken line (in this embodiment, white) Light).

  Further, in the LED lighting device of the present embodiment, two light emitting devices 1a, one light emitting device 1b, and one light emitting device 1c are conductors that serve as power supply paths to the respective light emitting devices 1a, 1a, 1b, 1c. The circuit board 2 having a pattern is mounted on one surface side. In addition, although the circuit board 2 is formed in the rectangular plate shape, it is not restricted to a rectangular plate shape, For example, you may be formed in disk shape.

  Each light-emitting device 1a, 1b, 1c includes blue LED chips 11a, 11b, 11c, rectangular plate-like mounting boards 12a, 12b, 12c on which blue LED chips 11a, 11b, 11c are mounted, and a translucent material ( Dome-shaped protective covers 13a, 13b, and 13c that are formed by surrounding the LED chips 11a, 11b, and 11c with the mounting substrates 12a, 12b, and 12c. It has. Here, the protective cover 13a contains only a red phosphor that is excited by light emitted from the blue LED chip 11a and emits red light, and the protective cover 13b is excited by light emitted from the blue LED chip 11b. The protective cover 13c contains only a transparent light diffusing material (eg, glass beads) such as glass beads that diffuses the light emitted from the blue LED chip 11c. It is included. In the present embodiment, each of the protective covers 13a, 13b, and 13c constitutes a protective unit. In the present embodiment, ceramic substrates are used as the mounting substrates 12a, 12b, and 12c, but the present invention is not limited to ceramic substrates.

  In addition, each light emitting device 1a, 1b, 1c has a sealing portion (for example, silicone resin) made of a translucent material that seals the LED chips 11a, 11b, 11c inside the protective covers 13a, 13b, 13c. (Not shown), and an air layer is formed between the inner surfaces of the protective covers 13a, 13b, and 13c and the light emitting surfaces of the sealing portions. Therefore, it is possible to suppress the light from propagating from the protective covers 13a, 13b, and 13c to the sealing portions, and to increase the light extraction efficiency to the outside. In addition, the light emission from each LED chip 11a, 11b, 11c is made to contain the light-diffusion material (for example, glass bead etc.), such as a glass bead, in the sealing part of each light-emitting device 1a, 1b, 1c. Is reflected and mixed by the light diffusing material in the sealing portion, so that the color mixing property can be improved. Further, the phosphor concentration of the protective covers 13a and 13b is different between the red light source and the green light source, and the blue color from the blue LED chips 11a and 11b and the light color from the phosphor are difficult to mix in a light phosphor concentration. Therefore, a diffusing material may be mixed in the color conversion members 13a and 13b.

  By the way, in the LED illuminating device of this embodiment, the blue LED chip of the same specification (The composition of a light emitting layer, the light emission peak wavelength, and a structure are the same) is used as each blue LED chip 11a, 11b, 11c.

  In the LED illumination device of the present embodiment described above, the two chromaticity points W1 and W2 defined on the black body locus BL in the xy chromaticity diagram and the black body locus BL at each of the two chromaticity points W1 and W2 are described. Of the chromaticity points R1, B1, G1 corresponding to the respective vertices of the triangle including the triangle connecting the three chromaticity points W1, W2, C with the chromaticity point C located at the intersection of the two tangents that are in contact with Three types of light emitting devices 1a, 1b, and 1c that emit light are provided, and each of the light emitting devices 1a, 1b, and 1c is made of a blue LED chip 11a, 11b, and 11c and a translucent material, and the blue LED chips 11a, 11b, and 11c are included. The light emitting device 1c that emits the color of the chromaticity point corresponding to one of the vertices is provided on the protective cover 13c with the blue LED chip 11c. The light emitting devices 1a and 1b that contain a diffusing material that diffuses the emitted light and emit the color of the chromaticity point corresponding to the other apex are provided on the protective covers 13a and 13b from the blue LED chips 11a and 11b. Since the phosphor which is excited by the emitted light and emits the color of the chromaticity point corresponding to the apex is contained, the color shift due to the surrounding environment and time can be suppressed, and all the light emitting devices 1a can be suppressed. , 1b, 1c need only be turned on, the circuit configuration for lighting is simple, and color reproducibility and color mixing can be enhanced with a simple configuration without performing feedback control. In manufacturing the LED lighting device of this embodiment, the blue LED chips 11a, 11b, and 11c having the same specifications are prepared for all the light-emitting devices 1a, 1b, and 1c, and are different for the light-emitting devices 1a, 1b, and 1c. Since it is only necessary to prepare the protective covers 13a, 13b, and 13c, it becomes easy to manufacture the light emitting devices 1a, 1b, and 1c, and it is possible to easily manufacture an LED lighting device that can suppress the occurrence of color misregistration. It becomes.

  In the LED lighting device of the present embodiment, the protective cover 13a of the light emitting device 1a contains only red phosphor as the phosphor, and the protective cover 13b of the light emitting device 1b contains only green phosphor as the phosphor. Since the protective cover 13c of the light emitting device 1c contains only the light diffusing material without containing the phosphor, a part of the green light emitted from the green phosphor is secondarily absorbed by the red phosphor. Conversion to red light can be suppressed, and the luminous efficiency of the phosphor can be improved.

  By the way, the chromaticity point G1 of the light emitting device 1b as the green light source is a curve between the chromaticity points W1 and W2 on the black body locus BL and the chromaticity in the xy chromaticity diagram shown in FIG. It is set within a region surrounded by a straight line between the points W2 and P2, a curve between the chromaticity points P2 and P1 on the spectrum locus SL, and a straight line between the chromaticity points P1 and W1, and serves as a red light source. The chromaticity point R1 of the light emitting device 1a is a straight line between the chromaticity points W1 and P3 and a line between the chromaticity points P3 and Q1 on the spectrum locus SL in the xy chromaticity diagram, and between the chromaticity points Q1 and W1. In the xy chromaticity diagram, the chromaticity point B1 of the light emitting device 1c as a blue light source is set in the region surrounded by the straight line between the chromaticity points W2 and P4 and the spectrum locus SL. It is desirable to set within an area surrounded by a line between chromaticity points P4 and Q2 and a straight line between chromaticity points Q2 and W2.Here, in the xy chromaticity diagram of FIG. 1B, the intersections of the straight line parallel to the bisector of the angle corresponding to the chromaticity point C through the chromaticity point W1 and the spectral locus SL are P1 and P3. The intersections between the straight line passing through the chromaticity point W2 and parallel to the bisector and the spectral locus SL are P2 and P4, and the intersection between the straight line connecting the chromaticity point W1 and the chromaticity point W2 and the spectral locus SL is Q1 and Q2 are provided, and the color reproducibility can be further enhanced by setting the chromaticity points G1, R1, and B1 in the respective areas.

  Further, in order to be able to change the color temperature on the black body locus BL, the relationship between the color temperature as shown in FIG. 2 and the current value of the drive current to each light emitting device 1a, 1b, 1c is measured in advance. A control device for controlling each lighting circuit (driving circuit) for lighting each light emitting device 1a, 1b, 1c is provided, and the color temperature and each light emitting device 1a, A table in which the current ratios 1b and 1c are associated with each other is stored, and the current value of the drive current to each of the light emitting devices 1a, 1b, and 1c is controlled based on the color temperature set by the operation of the operation unit. In this case, the color temperature can be adjusted on the black body locus BL.

  In relation to the color temperature and illuminance, a phenomenon called the Kruzov effect is widely known as a psychological effect of light on humans. As shown in FIG. 3, the range of illuminance that humans feel comfortable with color temperature. Therefore, even if the color temperature is changed, the illuminance should be within the comfortable range described above, and if the illuminance is adjusted to increase as the color temperature is increased, the person will be able to change the color temperature. It is possible to obtain light that feels comfortable.

  On the other hand, generally the feeling of brightness (the impression of brightness when a person sees the entire illuminated room) feels darker as the color temperature is lower, even at the same illuminance. Therefore, if the total luminous flux is adjusted so that the illuminance is higher as the color temperature is lower, a substantially constant brightness feeling can be given.

  In this embodiment, in the xy chromaticity diagram of FIG. 1B, the polygon is a triangle indicated by a broken line. However, the polygon is not limited to a triangle, and may be a polygon, for example, a pentagon indicated by a solid line. But you can. Alternatively, a diffusion panel formed of a diffusion transmissive material may be disposed so as to face the circuit board 2 and light emitted from each light emitting device 1a, 1b, 1c may be mixed by the diffusion panel. Further, instead of mounting each light emitting device 1a, 1b, 1c on the circuit board 2, for example, it is mounted on a base member such as a fixture body formed of a material having high thermal conductivity (such as metal) in a lighting fixture, A circuit board in which a plurality of window holes for exposing a part or all of each of the light emitting devices 1a, 1b, and 1c may be disposed to face the base member.

Regarding the LED lighting device of the embodiment, (a) is a schematic perspective view, (b) is an xy chromaticity diagram. It is explanatory drawing of the other structural example same as the above. It is a relation explanatory drawing of color temperature and illuminance. It is explanatory drawing of a prior art example. It is a schematic block diagram which shows another prior art example.

Explanation of symbols

1a Light emitting device (red light emitting device)
1b Light emitting device (green light emitting device)
1c Light emitting device (blue light emitting device)
2 Circuit board 11a, 11b, 11c Blue LED chip 12a, 12b, 12c Mounting board 13a, 13b, 13c Protective cover (protection part)
W1, W2, C, R1, G1, B1 Chromaticity point BL Black body locus SL Spectrum locus

Claims (2)

  An LED illumination device including a plurality of types of light emitting devices having different emission colors, two chromaticity points defined on a black body locus in an xy chromaticity diagram of an XYZ display system based on desired mixed color light, and In each of the two chromaticity points, the chromaticity point corresponding to each vertex of the polygon containing the triangle connecting the three chromaticity points with the chromaticity point located at the intersection of the two tangents that touch the black body locus. A plurality of types of light-emitting devices that emit light, the plurality of types of light-emitting devices each include a blue LED chip and a protective part that is made of a light-transmitting material and protects the blue LED chip, and each of the polygons The light emitting device that emits the color of the chromaticity point corresponding to one of the vertices includes a diffusing material that diffuses the light emitted from the blue LED chip in the protection unit, and the other of the polygons Light emitting device that emits the color of the chromaticity point corresponding to the vertex Is the protection unit, LED lighting apparatus characterized by that is contain a phosphor emitting color chromaticity points corresponding to the vertex is excited by the light emitted from the blue LED chip.   The polygon is a triangle, and the light emitting device includes only a blue light emitting device in which the protective portion contains only a diffusing material, and the protective portion includes only a red phosphor that emits red light as the phosphor. 2. The red light emitting device according to claim 1, and the green light emitting device in which the protection unit contains only a green phosphor that emits green light as the phosphor. LED lighting device.

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