JP5728440B2 - LED lighting device - Google Patents

Description

  The present invention relates to an LED lighting device, and more particularly, to an LED lighting device that is easy to assemble and maintain and can be focused according to an object to be irradiated.

  Unlike incandescent bulbs and fluorescent lamps, LEDs have problems such as directivity in light emission and generation of glare due to high-luminance light emitted from the LEDs. Further, since the LEDs have variations in light quantity and light color, there is a problem that non-uniform light is generated when a plurality of LEDs are used.

  For this reason, for example, an LED illumination device as shown in Patent Document 1 has been proposed. The LED illumination device includes an annular light guide, a number of LEDs that irradiate light from both side surfaces in the longitudinal direction of the light guide toward the inside of the light guide, and a cover that houses the light guide. The light of the LED is mixed inside the light guide and irradiated from the lower surface of the light guide. According to this LED illuminating device, the light from the LED is mixed by the light guide, thereby reducing the occurrence of glare and reducing variations in the light amount and the light color, thereby obtaining uniform light.

  However, by mixing the light from the LED with the light guide, it is possible to uniformly irradiate the irradiated object, but the light emitted from the light guide only irradiates the lower surface, and the inspection object On the other hand, there is a problem that only a single focus can be made, and it cannot be applied to various inspection objects.

For this reason, the present inventor has proposed an LED illumination device capable of making the optical axis of the incident light to the incident part different from the optical axis of the outgoing light from the light mixing part (Japanese Patent Application No. 2011-234253). . According to this LED illumination device, it is possible to solve the problems such as glare, uneven illuminance or uneven irradiation, and the angle of light emission can be changed, so that a plurality of focal points can be created, and the object (irradiated object) It is possible to create a focus that matches the body.

Japanese Patent No. 4659155

  However, the currently proposed LED lighting device has an excellent advantage of being able to create a focal point that matches an object (object to be irradiated), but when a different focal length is required, the LED lighting device is introduced. There has been a problem that the shape of the light body has to be changed in accordance with the focal length of each object (object to be irradiated). In this case, if the shapes of the plurality of light guides are made uniform, this leads to high costs in terms of cost.

  Accordingly, an object of the present invention is to provide an LED lighting device capable of realizing different focal lengths at low cost without changing the shape of the light guide in accordance with the focal length of each object (irradiated body). is there.

In order to achieve the above object, an LED lighting device of the present invention includes a substrate on which a plurality of LEDs are mounted, a light guide that is provided on the other surface of the substrate and emits incident light from the LED from a light emitting surface. In the LED lighting device, the light guide includes an incident portion that makes incident light from the LED enter the light guide body, and reflects the incident light incident on the incident portion in the light guide body. A light mixing portion for mixing light, and a light output portion for forming light emitted from the light output surface to the outside. A first reflecting surface which is smooth and reflects the incident light from the LED to the light mixing portion and is inclined with respect to the optical axis of the incident light; and The light that is provided at the opposite position and reflected by the first reflecting surface is different from the optical axis of the incident light. A second reflecting surface having a substantially circular cross section that emits light from the light emitting surface, and light reflected by the first reflecting surface provided at a position facing the first reflecting surface. And a third reflecting surface that is reflected in the light guide body, wherein the light output section has a Fresnel lens that is detachable from the light output surface.

  The LED illumination device according to the present invention is characterized in that the incident portion has a concave portion having an opening larger than the shape of the LED, and the concave portion is disposed so as to surround the LED.

  The LED lighting device of the present invention is characterized in that a reflective paint is applied to the concave inner wall surface of the concave portion.

  The LED lighting device according to the present invention is characterized in that the second reflecting surface is formed on a substantially spherical upper surface and / or side surface forming the light mixing portion.

  According to the present invention, a substrate on which a plurality of LEDs are mounted, an incident part that receives light emitted from the LEDs, a light mixing part that reflects and mixes light incident from the incident part, and the light mixing part Since a light guide having a light output portion for emitting light mixed in the outside to the outside and a Fresnel lens provided in the light output portion are provided, the object without changing the shape of the light guide Different focal lengths can be realized at low cost in accordance with the focal length of the (irradiated body).

It is sectional drawing of the light for visual inspection. It is the perspective view which showed the structure of the light for visual inspection. It is a perspective view which shows the lower surface side of the board | substrate with which LED was mounted. It is the perspective view which showed the modification of the board | substrate with which LED was mounted. It is the figure which showed the AA cross section of FIG. It is the perspective view which showed the modification of the board | substrate with which LED was mounted. It is the figure which showed the BB cross section of FIG. It is a perspective view which shows the upper surface side of the board | substrate with which LED was mounted. It is the perspective view which showed the structure of the heat sink. It is the perspective view which showed the structure of the light guide. It is sectional drawing which shows the structure of the light guide, and the installation state to a board | substrate. It is sectional drawing which shows the structure of the light guide, and the installation state to a board | substrate. It is sectional drawing which shows the structure of the light guide, and the installation state to a board | substrate. It is sectional drawing which showed the structure of the Fresnel lens sheet. FIGS. 13A to 13C are diagrams showing the behavior of light in the light guide. It is the figure which showed the modification of the light guide.

Hereinafter, with reference to the drawings, the LED illumination device according to the present embodiment will be described using a visual inspection light as an example.
FIG. 1 is a diagram showing the configuration of the visual inspection light 100.

  As shown in the figure, the visual inspection light 100 is applied to a loupe light so that the inspection object can be irradiated with light and the inspection object can be enlarged and viewed with a magnifying glass. The visual inspection light 100 dissipates heat generated from the LED 201, a metallic cover 101 having openings 101a and 101b on the upper and lower surfaces, a substrate 200 on which the LED 201 housed in the cover 101 is mounted. And a light guide 400 formed of a light-transmitting material, and a sheet-like Fresnel lens 500 provided on the lower surface of the light guide 400.

  Here, it is assumed that the LED 201 includes a red LED, a green LED, and a blue LED. Note that a three-color LED in which a red LED, a green LED, and a blue LED are integrated in one package may be used. Then, by adjusting the light emission of each color, it is possible to emit light of a color suitable for observing the inspection object. Moreover, since the light emitted from the LED 201 does not take heat, even if the specimen is a living thing, it can be observed without damaging the living thing.

FIG. 2 is a view of the visual inspection light 100 as viewed from below.
As shown in the figure, the visual inspection light 100 is configured in a ring shape. Although not shown, a magnifying glass is disposed in the opening 101a portion of the metallic cover 101 having the openings 101a and 101b. Further, the Fresnel lens 500 is provided so as to cover substantially the entire lower surface of the light guide 400.

FIG. 3 is a perspective view showing the lower surface side of the substrate 200 on which the LEDs 201 are mounted.
As shown in the figure, the substrate 200 is formed in a flat plate shape in a ring shape, and the LEDs 201 are mounted at equal intervals along the outer periphery of the lower surface side of the substrate 200. On the outer peripheral side of the substrate 200, a metal fitting 202 for installing and fixing the light guide 400 on the lower surface side and a control substrate 203 for performing lighting control of the LED 201 are provided.

4 is a diagram showing a first modification of the substrate 200 on which the LEDs 201 are mounted, and FIG. 5 is a cross-sectional view taken along the line AA ′ shown in FIG.
Since the same reference numerals are given to the same contents as those in FIG. 3, the overlapping description is omitted. However, as shown in the figure, a hole 20 is formed at a substantially central portion in the width direction of the substrate 200 on the lower surface side of the substrate 200. It is drilled concentrically with the outer periphery at equal intervals, and the LED 201 is mounted in the hole 20. As shown in FIG. 5, the hole 20 has a depth at which the LED 201 can be mounted, and a reflective paint 21 is applied to the wall surface thereof. The applied reflective paint 21 reflects the light emitted from the LED 201 and enters the light guide 400 without leakage.

6 is a view showing a second modification of the substrate 200 on which the LEDs 201 are mounted, and FIG. 7 is a cross-sectional view taken along the line BB ′ shown in FIG.
3 and 4 are given the same reference numerals and redundant description is omitted, but as shown in the figure, a groove portion 30 concentric with the substrate 200 is formed on the lower surface side of the substrate 200. The LEDs 201 are mounted on the bottom surface of the groove 30 at equal intervals. As shown in FIG. 7, the groove 30 has a depth at which the LED 201 can be mounted.

FIG. 8 is a perspective view of the upper surface side of the substrate 200 on which the LED 201 is mounted, that is, the side opposite to the side shown in FIGS. 3, 4, and 6.
As shown in the figure, a metal fitting 202 is provided on the upper surface side of the substrate 200. As described above, the metal fitting 202 is also connected to the lower surface side of the substrate 200. The light guide 400 is fixed on the lower surface side, and the substrate 200 is fixed to the cover 101 on the upper surface side.

FIG. 9 is a perspective view showing the configuration of the heat sink 300.
As shown in the figure, the heat radiating plate 300 has a flat plate shape and a ring shape, and is configured to be substantially the same as the outer diameter and inner diameter of the substrate 200. The heat radiating plate 300 is for radiating heat generated by driving the LED 201, and is installed on the upper surface side of the substrate 200. In addition, the heat sink 300 is formed with a metal (for example, aluminum etc.) with high heat conductivity.

FIG. 10 is a perspective view of the light guide 400 as seen from the upper surface side.
As shown in the drawing, the light guide 400 is a material having heat resistance, insulation, and light transmission, and is formed in a substantially ring-shaped shape using, for example, an acrylic resin or a polycarbonate resin. In addition, a reflection film for reflecting light emitted by the LED 201 is formed on a part of the light guide 400.

11 to 13 are cross-sectional views showing the structure of the light guide 400 and the state of installation on the substrate.
As shown in the drawing, the light guide 400 includes an incident portion 401 that allows light from the LED 201 to enter, and a light mixing portion 402 that mixes incident light.

The incident portion 401 includes a concave portion 401 a that surrounds the installation site of the LED 201, and a reflective surface 401 c that reflects the light emitted from the LED 201 into the light guide 400. The opening of the recess 401a is larger than the LED 201. For example, when the LED 201 is mounted on the substrate 200 as shown in FIG. The opening is positioned directly below the LED 201 and covers the LED 201 (FIG. 11).
Further, as shown in FIG. 4, when the LED 201 is mounted on the bottom surface of the hole 20 of the substrate 200, the opening of the recess 401a is located directly below the hole 20 (FIG. 12). The light emitted from the LED is reflected by the reflective paint applied to the wall surface 21 and enters the incident portion 401.
Furthermore, as shown in FIG. 6, when the LED 201 is mounted on the bottom surface of the groove portion 30 of the substrate 200, the width of the groove portion 30 is larger than the concave portion 401 a, so that the concave portion 401 a fits into the groove portion 30, thereby opening the concave portion 401 a. Is located directly below the LED 201 and covers the LED 201 (FIG. 13).
A reflective paint 401b that reflects the light emitted from the LED 201 is applied to the inner wall surface of the recess 401a. The light emitted from the LED 201 is reflected by the reflective paint 401b, so that the light emitted from the LED 201 is reflected without omission. It can be reflected on the surface 401c.

The reflective surface 401c is linearly inclined toward the inner diameter side of the light guide 400, and a white paint is applied to the inclined surface to form a reflective film. The inclination angle R of the inclined surface can be changed within a range of 30 to 50 °, and the focal distance to the inspection object can be changed by changing the inclination angle R.
In addition, this reflective surface 401c may be arc-shaped, and its shape may be changed depending on the object to be irradiated.

  The light mixing section 402 has a substantially circular top surface in cross-sectional shape, a reflective surface 402a coated with a reflective paint, a straight side surface, a reflective surface 402b coated with a reflective paint, and a straight bottom surface. Thus, it is formed from a light exit surface 402 c that emits light mixed in the light mixing section 402. A Fresnel lens 500 is provided on the light exit surface 402c.

  In the light mixing unit 402, the light of the LED 201 reflected on the reflection surface 401c of the incident unit 401 is repeatedly reflected on the reflection film formed on the inner walls of the upper surface 402a and the side surface 402b, and is mixed in the light mixing unit 402 and mixed. The emitted light is emitted toward the central axis of the light guide 400 through the Fresnel lens 500.

FIG. 14 is a cross-sectional view showing the configuration of the Fresnel lens 500.
The Fresnel lens 500 is formed of an acrylic resin, a polycarbonate resin, or the like, and has an adhesive surface 501 that adheres to the light exit surface 402c of the light guide 400 in a substantially flat shape on one surface, and a plurality of surfaces on the other surface. And a lens portion 502 having a substantially triangular cross section.

  The light exit surface 402c of the light guide 400 can be formed into a substantially spherical surface, and the focal length according to various inspection objects can be created by changing the curvature of the spherical surface. For this purpose, the light guide having a spherical surface with various curvatures. It is necessary to prepare 400, which causes high costs. In addition, it is difficult to prepare the light guide 400 that creates a focal length corresponding to the inspection object because the cost increases even when the light exit surface 402c is processed into a substantially spherical shape.

  Therefore, the light exit surface 402c of the light guide 400 can be made substantially planar, and the Fresnel lens 500 can be attached to the light exit surface 402c to create a focal length corresponding to the test object. As described above, the Fresnel lens 500 has an adhesive surface 501 on one side, and can be easily adhered to or removed from the light exit surface 402c of the light guide 400.

Further, the focal length can be changed by deforming the substantially triangular structure of the Fresnel lens portion 502. Furthermore, aligning the Fresnel lens 500 capable of creating various focal lengths can reduce costs compared to processing the light exit surface 402c of the light guide 400 into a substantially spherical shape.

  Therefore, the Fresnel lens 500 capable of creating various focal lengths is prepared, and the Fresnel lens 500 having a focal length corresponding to the inspection object is adhered to the light output surface 402c of the light guide 400, so that it can correspond to the inspection object. An LED lighting device can be provided.

Next, the behavior of light in the light guide 400 will be described in detail with reference to FIG.
Fig.15 (a)-FIG.15 (c) are the figures which showed the behavior of the light within a light guide.
As shown in the drawing, the light emitted from the LED 201 enters the incident portion 401 and is reflected by the reflecting surface 401c (FIG. 15A). At this time, the light emitted from the LED 201 is reflected on the wall surface 401b on which the reflective paint of the concave portion 401a of the incident portion 401 is applied, so that the light can be incident into the light guide 400 without leakage.

  The light reflected on the reflection surface 401c enters the light mixing portion 402, is reflected on the reflection surface 402a on the upper surface of the light mixing portion 402, and is reflected again on the reflection surface 401c (FIG. 15B). In the light mixing unit 402, the light reflected on the reflection surface 401c is again reflected on the reflection surfaces 402a and 402b, and the light is repeatedly reciprocated in the light guide 400 by so-called pumping to be mixed. Then, the mixed light exits from the light exit surface 402c via the Fresnel lens 500, and is irradiated on the lower surface of the LED illumination device 100 (FIG. 15C).

At this time, since the Fresnel lens 500 is configured to condense on the central axis of the light guide 400, the emitted light can be focused on the central axis to form a focal point.
Further, the light emitted from the LED 201 is mixed in the light guide 400, so that the inspection object can be uniformly irradiated, and unevenness in illuminance can be eliminated.

FIG. 16 is a view showing a modification of the light guide 400.
The illustrated light guide 400 corresponds to the LEDs 201 mounted on the outer peripheral side and the inner peripheral side of the substrate 200 in order to increase the illuminance of the visual inspection light 100.
In such a case, the light guide 400 is configured to include the incident portions 401 on the outer diameter side and the inner diameter side. The light emitted from each LED 201 enters the respective incident portions 401, is reflected by the reflecting surface 401 c, and enters the light mixing portion 402. In the light mixing unit 402, the light is reflected by the reflection surface 402a on the upper surface, and is emitted from the Fresnel lens 500 on the lower surface by repeating the pumping described above.

  In addition, the visual inspection light 100 as an example of the LED lighting device described above has a substrate, a heat sink, or a light guide formed in a ring shape (substantially ring-shaped), and a magnifying glass (not shown) in the opening 101a. Although it is the structure to arrange | position, the shape of these board | substrates, a heat sink, or the light guide 400 is not limited to a ring shape (substantially ring-ball shape). If this is formed, for example, in a straight tube type, it can be provided as a fluorescent lamp using LEDs. Moreover, it can design freely according to a use aspect.

100 Light for visual inspection (LED lighting device)
101 Cover 101a, 101b Opening 200 Substrate 201 LED
202 Metal fitting 300 Heat sink 400 Light guide 401 Incident part 401a Concave part 401b, 401c Reflective surface 402a, 402b Reflective surface 402c Light exit surface 402 Light mixing part 500 Fresnel lens

Claims (4)

In an LED illumination device comprising: a substrate on which a plurality of LEDs are mounted; and a light guide that is provided on the other surface of the substrate and emits incident light from the LEDs from a light exit surface.
The light guide includes an incident part that makes incident light from the LED enter the light guide, and a light mixing part that reflects and mixes the incident light incident on the incident part in the light guide, The light exit surface is formed in a straight line, and comprises a light exit portion that emits light mixed in the light blend portion to the outside from the light exit surface,
The incident part has a first reflecting surface that is smooth to reflect incident light from the LED to the light mixing part and is inclined with respect to the optical axis of the incident light,
The light mixing section is provided at a position facing the light exit surface, and has a substantially circular cross section in which the light reflected by the first reflection surface is made different from the optical axis of the incident light and is emitted from the light exit surface. A second reflecting surface and a third reflecting surface that is provided at a position facing the first reflecting surface and reflects the light reflected by the first reflecting surface together with the second reflecting surface within the light guide. Have
The light exit portion has a Fresnel lens that is removable from the light exit surface.
LED lighting device characterized by the above.   The LED illumination device according to claim 1, wherein the incident portion has a concave portion having an opening larger than the shape of the LED, and the concave portion is disposed so as to surround the LED. The LED lighting device according to claim 2 , wherein a reflective paint is applied to the concave inner wall surface of the concave portion.   The LED lighting device according to claim 1, wherein the second reflecting surface is formed on a substantially spherical upper surface and / or side surface forming the light mixing portion.

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