JP4086020B2 - LED lighting source - Google Patents

Description

  The present invention relates to an LED illumination light source for general illumination.

  A light-emitting diode element (hereinafter referred to as an “LED element”) is a semiconductor element that is small, efficient, and emits brightly colored light, and has an excellent monochromatic peak. When emitting white light using an LED element, for example, it is necessary to arrange a red LED element, a green LED element, and a blue LED element in close proximity to perform diffusion color mixing, but each LED element has an excellent monochromatic peak. Therefore, color unevenness is likely to occur. That is, if the light emission from each LED element is not uniform and color mixing is not successful, white light emission with uneven color will occur. In order to solve the problem of such color unevenness, a technique for obtaining white light emission by combining a blue LED element and a yellow phosphor has been developed (for example, Patent Document 1 and Patent Document 2).

  According to the technique disclosed in Patent Document 1, white light emission is obtained by light emission from a blue LED element and light emission from a yellow phosphor that is excited by the light emission and emits yellow light. In this technique, since white light emission is obtained using only one type of LED element, the problem of color unevenness that occurs when white light emission is obtained by bringing a plurality of types of LED elements close to each other can be solved.

In addition, since one LED element has a small luminous flux, in order to obtain a luminous flux equivalent to that of incandescent bulbs and fluorescent lamps that are widely used today as a light source for general illumination, a plurality of LED elements are arranged and LEDs are arranged. It is desirable to construct an illumination light source. Such LED illumination light sources are disclosed in, for example, Patent Document 3 and Patent Document 4.
Japanese Patent Laid-Open No. 10-242513 Japanese Patent No. 2998696

  Japanese Patent Application No. 2003-31634 (Applicant; Matsushita Electric Industrial Co., Ltd.) discloses an LED illumination light source that can solve the problem of color unevenness of the bullet-type LED illumination light source disclosed in Patent Document 2. ing. First, an LED illumination light source that can solve this color unevenness problem will be described.

  The bullet-type LED illumination light source disclosed in Patent Document 2 has a configuration as shown in FIG. That is, the bullet-type LED illumination light source 200 shown in FIG. 1 includes an LED element 121, a bullet-shaped transparent container 127 that covers the LED element 121, and lead frames 122 a and 122 b for supplying current to the LED element 121. A cup-shaped reflector 121 that reflects light emitted from the LED element 121 in the direction of arrow D is provided on the mount portion of the frame 122b on which the LED element 121 is mounted. The LED element 121 is sealed with a first resin portion 124 in which a fluorescent material 126 is dispersed. The first resin portion 124 is covered with a second resin portion 125. When blue light is emitted from the LED element 121 and the fluorescent material 126 emits yellow light by the light, both colors are mixed to obtain white. However, because the first resin portion 124 is formed by filling the cup-shaped reflecting plate 123 so as to seal the LED element 121 and then curing it, the first resin portion 124 is enlarged as shown in FIG. Concavities and convexities are likely to occur on the upper surface of the resin part 124, resulting in unevenness in the thickness of the resin containing the fluorescent material 126, and the path through which the light from the LED element 121 passes through the first resin part 124 (for example, The amount of the fluorescent material 126 present on the optical paths E and F) varies, resulting in uneven color.

  In order to solve such a problem, in the LED illumination light source disclosed in the specification of Japanese Patent Application No. 2003-31634, the reflecting surface of the light reflecting member (reflecting plate) is separated from the side surface of the resin portion in which the fluorescent material is dispersed. It is configured to let you. 3A and 3B are a side sectional view and a top view showing an example of an LED illumination light source disclosed in Japanese Patent Application No. 2003-31634. In the LED illumination light source 300 shown in FIGS. 3A and 3B, the LED element 112 mounted on the substrate 111 is covered with a resin portion 113 in which a fluorescent material is dispersed. A reflective plate 151 having a reflective surface 151 a is attached to the substrate 111, and the side surface of the resin portion 113 and the reflective surface 151 a of the reflective plate 151 are formed apart from each other. Since the side surface of the resin portion 113 is formed away from the reflection surface 151a of the reflection plate 151, the shape of the resin portion 113 can be freely designed without being restricted by the shape of the reflection surface 151a of the reflection plate 151. As a result, the effect of reducing color unevenness can be exhibited.

  When a plurality of the configurations shown in FIG. 3 are arranged in a matrix, the configuration is as shown in FIG. In the LED illumination light source 300 shown in FIG. 4, the resin portions 113 covering the LED elements 112 are arranged in a matrix on the substrate 111, and the reflection plate 151 having the reflection surface 151a corresponding to each resin portion 113 is the substrate. 111 is attached. With such a configuration, since the light flux of a plurality of LED elements can be used, it becomes easy to obtain a light flux equivalent to that of a general illumination light source (for example, an incandescent bulb or a fluorescent lamp) that is widely used today. .

  If the above measures are taken, theoretically, the color unevenness disappears, and an LED illumination light source without color unevenness can be realized.

  However, as a result of further trial production by the present inventors, it has become clear that color unevenness may easily occur due to the accuracy in the process. An example of this case is shown in FIG. The accuracy of the arrangement of the resin part 502 with respect to the LED element 501 depends on the repeatability of the device in which the resin part 502 is arranged. For this reason, the center of the LED element 501 and the center of the resin portion 502 may not coincide with each other. For example, as shown in FIG. 5A, the thickness 502b of the resin portion 502 on the left side of the LED element 501 is thinner than the thickness 502a of the resin portion 502 on the right side of the LED element 501. As a result, the irradiation light 510 emitted from the upper surface portion of the LED element 501, the irradiation light 530 emitted from the right side surface of the LED element 501 and reflected by the reflection plate 503, and emitted from the left side surface of the LED element 501 and reflected by the reflection plate 503. Since the light colors of the reflected irradiation lights 520 are different, color unevenness occurs. In the resin portion 502a, the thickness of the resin portion 502 containing the phosphor is larger than that of the resin portion 502b. Therefore, the irradiation light 520 is yellowish compared to the irradiation light 510, and conversely, the irradiation light 530 is blue. It becomes a tinged color.

  FIG. 5B shows a conceptual diagram of the state of color unevenness on the irradiated surface drawn corresponding to the position of the drawing of FIG. The horizontal axis represents the position of one axis selected on the irradiation surface with the LED illumination light source, and the vertical axis represents the color temperature on that axis. As shown in FIG. 5B, the color difference ΔE1 between the irradiation light 520 and the irradiation light 530 on the irradiation surface is 6000K.

Here, the implementation conditions and the like of this time are as follows. The LED element 501 has a square shape, and has dimensions of an upper surface area of 0.3 mm ² and a thickness of 0.1 mm. The reflector 503 was prepared with a pilot hole of 1.0 mm, an upper hole of 2.5 mm, a thickness of 10 mm, and a parabolic shape. The resin portion 502 has a cylindrical shape with a diameter of 0.75 mm and a thickness of 0.25 mm. In the color temperature measurement, in order to eliminate the influence of the shape accuracy and arrangement accuracy of the reflecting plate 503, the light from the upper and side surfaces of the resin portion 502 is measured with the reflecting plate 503 removed, and the irradiated light 520, 530. Color temperature. Specifically, the sample of FIG. 5A from which the reflecting plate 503 is removed is placed on an x, y turntable with the irradiation surface sideways, and a spectroscopic measurement device is placed at a distance of 100 mm from the irradiation surface. By rotating the xy turntable, the color temperature irradiated from the upper surface and side surface of the resin portion 502 can be measured. Measurements were made every 5 degrees.

  Since these color irregularities are caused by the accuracy of the device in which the resin portion 502 is arranged on the LED element 501, it is very difficult to completely eliminate the color irregularities in consideration of process variations and the like. Therefore, a means for making the color unevenness that has come out inconspicuous is indispensable.

  The present invention has been made in view of such a point, and a main object thereof is to provide an LED illumination light source using an optical system in order to make color unevenness inconspicuous.

  In order to solve the above problems, the LED illumination light source of the present application includes an LED element, a substrate on which the LED element is mounted, a resin portion including a phosphor applied to the surface of the LED element, and the LED element. An LED illumination light source comprising: a reflective plate attached to the substrate, wherein the substrate contacts the substrate more than an area of an upper surface portion on which the LED element is mounted. A mirror-finished convex structure having a larger lower surface area is attached, and light from the LED element is emitted from the opening of the reflecting plate to the opening of the contact portion of the substrate. The area of the opening formed is smaller.

  As a preferred embodiment, the opening of the reflector has a truncated cone shape, and the convex structure has a truncated cone shape.

  As a preferred embodiment, the light from the LED element that has passed through the resin portion is reflected by a reflecting mirror, and the reflected light is further reflected by a convex structure and emitted to the outside of the reflecting mirror. .

  As a preferred embodiment, it further includes a lens that is provided in the opening of the reflecting plate and collects light from the LED element.

  As described above, the LED illumination light source according to the present invention is provided with a mirror-finished convex structure in which the area of the lower surface portion in contact with the substrate is larger than the area of the upper surface portion on which the LED element is mounted on the substrate. In addition, the opening of the reflecting plate has a configuration in which the area of the opening from which the light from the LED element is emitted is smaller than the area of the opening of the contact portion of the substrate. With this configuration, color unevenness can be reduced even when the center of the LED element and the center of the resin portion including the phosphor applied to the LED element are deviated.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 6 shows an LED illumination light source 600 according to the first embodiment of the present invention.

  6, in the LED illumination light source 600, an LED element 614, a substrate 613 on which the LED element 614 is mounted, a resin portion 615 including a phosphor applied to the surface of the LED element 614, and the LED element 614 are arranged. And a reflector 617 attached to the substrate 613.

  The opening of the reflecting plate 617 has a smaller area of the opening from which light from the LED element 614 is emitted than the area of the opening of the contact portion of the substrate 613. In this embodiment, the opening is a truncated cone, the substrate exists in a direction in which the cross-sectional area perpendicular to the rotation axis of the truncated cone increases, and the LED element in the direction in which the cross-sectional area perpendicular to the rotation axis of the truncated cone decreases. Light is emitted.

  A convex structure 612 on which the LED element 614 is mounted is attached to the substrate 613. As for the convex structure 612, the area of the lower surface part which contacts the board | substrate 613 is larger than the area of the upper surface part in which the LED element 614 is mounted. In this embodiment, the convex structure 612 is a truncated cone, and the surface is mirror-finished.

  The side surface of the resin portion 615 is formed away from the reflection surface 616 of the reflection plate 617. Since the side surface of the resin portion 615 is formed apart from the reflection surface 616 of the reflection plate 617, light emitted mainly from the side surface of the resin portion 615 is reflected by the reflection surface 616 of the reflection plate 617. The light reflected by the reflecting surface 616 is applied to the reflecting surface 611 of the convex structure 612. The irradiated light is reflected again by the reflecting surface 611 and enters the office as irradiated light 618 from the opening of the reflecting mirror 617.

  In the present embodiment, the convex structure 612 of the substrate 613 is a truncated cone, and the dimensions are an upper surface φ0.9 mm, a lower surface φ1.7 mm, and a height 0.2 mm. The LED element 614 is a blue LED having a peak wavelength at 470 nm, and has a size of 0.3 mm square and a thickness of 0.1 mm. The shape of the resin portion 615 in which the fluorescent material is dispersed is a cylindrical shape, and φ0.8 mm and a height of 0.3 mm are used. The reflection plate 617 was a truncated cone, and the upper hole was φ1.9 mm and the lower hole was φ2.3 mm.

  It should be noted that the size of each of these members is only an example, and it is needless to say that there is no particular problem even if the size is any size as long as the irradiation light 618 can be emitted closer to the resin portion 615 than the reflector 617. That is, each size is such that light from the LED element 614 that has passed through the resin portion 615 is reflected by the reflecting plate 617, and the reflected light is further reflected by the convex structure and emitted from the reflecting mirror 617. As long as it is in a positional relationship and an angle.

  As a material for the substrate 613, a composite substrate having excellent heat dissipation was used. The convex structure 612 of the substrate 613 is plated with metal such as silver or chrome so as to be specularly reflected. In this embodiment, chrome plating was performed. The reflecting plate 617 was made by cutting an aluminum plate so that it could be mirror-reflected. There is no problem even if a mirror surface is formed by metal plating on a resin material like the convex structure 612 of the substrate 613. The reflectance is preferably 70% or more so as not to reduce the luminous flux as much as possible.

  As described above, since the light emitted from the side surface of the resin portion 615 is designed to irradiate around φ1.2 mm around the resin portion 615, it is more central than the configuration shown in FIG. It is focused on.

  7A, in the LED illumination light source 600 configured as shown in FIG. 6, the state of light emitted from the LED illumination light source 700 when the center of the LED element 701 and the center of the resin portion 113 are shifted. Is shown schematically. FIG.7 (b) shows the conceptual diagram of the state of the nonuniformity with respect to the irradiation surface drawn corresponding to the position of drawing of Fig.7 (a). The color temperature measurement is the same as in FIG. The horizontal axis indicates the position on the irradiation surface with the LED illumination light source 700, and the vertical axis indicates the color temperature on that axis.

  The irradiation light 720 emitted from the upper surface portion of the LED element 701 in FIG. 7A, the irradiation light 740 emitted from the right side surface of the LED element 701 and reflected by the reflecting plate 710, and emitted from the left side surface of the LED element 701 and reflected. Each light color of the irradiation light 730 reflected by the plate 710 is a different light color as described in FIG. Since the resin portion 702a is thicker than the resin portion 702b, the irradiation light 730 has a yellowish color and the irradiation light 740 has a blueish color compared to the irradiation light 720. In this embodiment, as shown in FIG. 7B, the color difference ΔE2 between the irradiation light 740 and the irradiation light 730 is 3000K (= 6500K-3500K). Compared with the case of the conventional LED illumination light source of FIG. 5B, in this embodiment, the irradiation light 720, 730, 740 is mixed due to the narrow irradiation angle as shown in FIG. It becomes smaller than the color difference ΔE1 (= 6000K) of b).

  As described above, by configuring the LED illumination light source 600 as shown in FIG. 6, even when the center of the LED element 614 and the center of the resin portion 615 are deviated, color unevenness can be reduced.

  That is, in the LED illumination light source according to the present embodiment, the LED chip, the substrate on which the LED chip is mounted, the area of the lower surface part is larger than the area of the upper surface part, and the convex surface is a mirror surface on the upper surface. A resin that covers the LED chip by including a phosphor that absorbs light from the LED chip and emits light having a longer wavelength than the light, and a reflector plate having a lower surface hole larger than the upper surface hole and a mirror surface The light emitted from the side surface of the part and the light emitted from the upper surface are further mixed in color, and color unevenness can be reduced.

(Embodiment 2)
FIG. 8 shows an LED illumination light source 800 according to the second embodiment of the present invention. In FIG. 8, the difference from the configuration of the first embodiment is that a lens 810 is provided. The same configurations as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  Since the irradiation light 820 is further condensed by the lens 810, the color unevenness is further reduced.

  As described above, in the LED illumination light source 800 of the present embodiment, the illumination light is collected by having the lens on the illumination surface side of the LED element, and the color unevenness of the illumination light is reduced. Can do.

  FIG. 9 shows a state where the reflecting plate 617 and the substrate 613 are covered with the resin constituting the lens 910 and the LED element 614 is sealed. By being completely sealed by the resin used for the lens 910, the humidity in the vicinity of the LED element 614 is kept constant, so that problems such as ion migration can be avoided.

  FIG. 10 shows a configuration in which the resin part 615 including the phosphor covering the LED element is removed from FIG. Although it is not a viewpoint of color unevenness, as is clear from the irradiation light beams 520 and 530 in FIG. 5, the irradiation light 1010 is useful for the effect of narrowing the light distribution by condensing.

  Since the LED illumination light source of the present invention can reduce color unevenness, it is useful as an LED illumination light source for general illumination.

The figure which shows the cross section of the conventional LED illumination light source The enlarged view which shows the cross section of the reflection part of the conventional LED illumination light source (A) is a cross-sectional view of an LED illumination light source previously invented by the applicant, and (b) is a top view of the LED light source previously invented by the applicant. A perspective view of the LED illumination light source previously invented by the applicants in a modularized state (A) is sectional drawing which shows the mode of reflection of a LED illumination light source which the applicants devised before, (b) is a graph which shows the color temperature of the LED illumination light source of (a) Sectional drawing of the LED illumination light source 600 of one Embodiment in this invention (A) is sectional drawing which shows the mode of reflection of the LED illumination light source 700 of one Embodiment in this invention, (b) is a graph which shows the color temperature of the LED illumination light source 700 of one Embodiment in this invention of (a). Sectional drawing of the LED illumination light source 800 of one Embodiment in this invention Sectional drawing of the LED illumination light source 900 of one Embodiment in this invention Sectional drawing of the LED illumination light source 1000 of one Embodiment in this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 111 Board | substrate 112 LED element 113 Resin part 151 Reflector 151a Reflective surface 152 Irradiation light 121 LED element 122a Lead frame 123 In-cup reflector 124 First resin part 125 Second resin part 126 Fluorescent substance 127 Transparent container 200 Cannonball type LED Illumination light source 300 LED illumination light source 501 LED element 502 Resin part 502a Resin part 502b Resin part 503 Reflection plate 510 Irradiation light 520 Irradiation light 530 Irradiation light 600 LED light source 611 Reflecting surface 612 Convex structure 613 Substrate 614 LED element 615 Resin part 616 Reflection Surface 617 Reflector 618 Irradiation light 701 LED element 702a Resin part 702b Resin part 720 Irradiation light 730 Irradiation light 740 Irradiation light 810 Lens 820 Irradiation light 910 Sealing part 1010 Irradiation light

Claims (4)

An LED element;
A substrate on which the LED element is mounted;
A resin part containing a phosphor applied to the surface of the LED element;
A reflector having an opening in which the LED element is disposed and attached to the substrate;
An LED illumination light source comprising:
The substrate is attached with a mirror-finished convex structure having a larger area of the lower surface portion contacting the substrate than the area of the upper surface portion on which the LED element is mounted,
The LED illumination light source, wherein the opening of the reflecting plate has a smaller area of the opening from which light from the LED element is emitted than the area of the opening of the contact portion of the substrate. The opening of the reflector has a truncated cone shape,
The LED projection light source according to claim 1, wherein the convex structure has a truncated cone shape. The light from the LED element that has passed through the resin portion is reflected by a reflecting mirror, and the reflected light is further reflected by a convex structure and emitted to the outside of the reflecting mirror. The LED illumination light source described in 1. The LED illumination light source according to any one of claims 1 to 3, further comprising a lens that is provided at an opening of the reflection plate and collects light from the LED element.

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