JP2008016303A - Light emitting device - Google Patents

Abstract

Even when a light source that emits light with a narrow light emission angle and different wavelength components is applied, the light use efficiency can be improved and the uniformity of the illuminance distribution can be improved. Provided is a light-emitting device capable of suppressing the occurrence of color unevenness on an irradiation surface.
A light emitting device 1 of the present invention includes an LED lamp 3 that emits light in which different wavelength components are mixed, and an optical component unit 12 that converts light emitted from the LED lamp 3 into parallel light with respect to an optical axis. And a fly-eye lens 7 for condensing the parallel light emitted from the optical component unit 12 by the incident side lens unit 7a and projecting the collected light on the infinity surface by the output side lens unit 7b.
[Selection] Figure 1

Description

  The present invention relates to a light emitting device used for illumination, for example.

  2. Description of the Related Art A light emitting device configured by embedding a light emitting diode element in a recess provided with a reflector is known (see, for example, Patent Documents 1 and 2).

  In this type of light emitting device, for example, a phosphor layer containing a yellow light emitting phosphor in a resin is filled in a recess, and a light emitting diode element that emits blue light is applied, whereby the light emitting diode element emits light. The blue light and the yellow light emitted from the yellow light emitter excited by the blue light are mixed to emit white light.

  Further, in such a light emitting device, a lens is disposed at a position facing the concave portion to enable light distribution control. In addition, as a lens to be disposed opposite to the concave portion, one or two fly-eye lenses are used, and a technique for arranging the fly-eye lenses at a predetermined interval with respect to a plurality of light emitting diode elements has also been proposed. Yes. (For example, refer to Patent Document 1).

  Conventionally, a critical illumination method is known as an illumination method. In this critical illumination method, a light source image is formed on an irradiated surface. For this reason, since the luminance distribution on the surface of the light source becomes the luminance distribution on the irradiated surface as it is, it is difficult to make the luminance distribution uniform, and a light source image is also formed on the irradiated surface, resulting in uneven illuminance. .

The critical illumination method is useful when there is a limitation on the size of the entire light source system or the number of lenses because the illumination efficiency is high and the light source system has a relatively simple structure. That is, as in Patent Documents 1 and 2, most of the lenses used in the light-emitting device having a configuration in which the light-emitting diode element is embedded in the concave portion apply the critical illumination method.
JP-A 61-147585 JP 2003-281908 A JP 2005-190954 A

  As described above, in the conventional critical illumination method, when the luminance distribution of the light source is not uniform, it is difficult to obtain a uniform luminance distribution on the irradiated surface. In addition, in a light source that emits blue light from the light emitting diode element in the center of the recess and yellow light from the phosphor layer in the entire area of the recess and emits white light by mixing these lights, the recess is exposed from the outside. When viewed, the luminance distribution of the light source is not uniform. In other words, the illuminance of blue light has a high distribution in the central area of the irradiated surface, while the color unevenness has a distribution of high illuminance of yellow light in the peripheral area of the irradiated surface.

  Further, in the light emitting device of Patent Document 3, since the fly-eye lens is disposed with a predetermined interval with respect to the light-emitting diode element, the parallel light emitted from the light-emitting diode element in the optical axis direction is the fly-eye lens. However, the light emitted from the light emitting diode element in the direction intersecting the optical axis direction does not enter the fly-eye lens or is reflected by the lens surface, and the light source There are cases where light cannot be extracted efficiently.

  Further, in the light emitting device of Patent Document 3, as described above, since the fly-eye lens is arranged at a predetermined interval with respect to the concave portion provided with the light emitting diode element and the phosphor layer, light is emitted from the light emitting diode element. The blue light emitted in the axial direction is easy to enter the fly-eye lens, and the light extraction efficiency is good. However, since the yellow light emitted from the phosphor layer has a smaller proportion of parallel light emitted than the blue light, the amount incident on the fly-eye lens is small, and the light extraction efficiency is lowered. For this reason, on the irradiated surface, the luminous intensity of blue light is high, the luminous intensity of yellow light is low, and color unevenness is likely to occur.

  Furthermore, in the case of the device of Patent Document 3, the light distribution control becomes easier as the light source and the fly-eye lens are further separated, but on the other hand, the light extraction efficiency is lowered.

  The present invention provides a light-emitting device that can improve the light extraction efficiency and make the illuminance distribution uniform in a light source that emits light in which different wavelength components are mixed, and can further suppress the occurrence of color unevenness on the irradiated surface. For the purpose of provision.

  In order to achieve the above object, the invention according to claim 1 is a light source that emits light in which different wavelength components are mixed; and a light control means that makes the light emitted from the light source parallel to the optical axis; A lens body having a first lens for condensing the parallel light and a second lens for projecting the light collected by the first lens onto an infinite surface. The light emitting device is characterized.

  That is, in the first aspect of the invention, the light emitted from the light source and expanding, for example, radially, is first collected as a light flux parallel to the optical axis through the light control means, and then the parallel light is imaged by the first lens. Since the second lens projects onto the surface at infinity, the light collection rate can be increased.

More specifically, in the first aspect of the invention, the light source image is formed in the front stage of the second lens, that is, in the front stage of the projection lens, so that the imaging portion having a positional relationship of the conjugate with the light source is moved to the rear stage side. The shifted position becomes the irradiated surface. As a result, even when a light source that emits light with different wavelength components is applied, the influence of variations in the luminance distribution of the light source itself does not appear directly on the irradiated surface. The influence of unevenness is reduced, and a uniform illuminance distribution can be obtained on the irradiated surface.
Here, each of the first lens and the second lens included in the lens body may be an integral structure or a separate structure.

The light-emitting device according to claim 2 is the light-emitting device according to claim 1, wherein the light control means is provided between the first lens and the light source disposed at a predetermined focal position. A third lens that emits light emitted from a light source and emits parallel light; and surrounds the light source and the first lens with a paraboloid with respect to the focal position and the first lens side And a reflecting member that radiates light from the light source and does not pass through the third lens to be reflected by the paraboloid to be parallel light.
That is, in the light emitting device according to the second aspect, all the light emitted from the light source can be collimated and incident on the first lens while the third lens and the reflecting member cooperate.

The light emitting device according to claim 3 is the light emitting device according to claim 1 or 2, wherein the third lens has a conical virtual shape connecting the inner peripheral edge of the opening of the reflecting member and the focal position. It is arrange | positioned in the position which touches a surface.
In the light emitting device according to the third aspect, the parallel light emitted from the rear stage of the third lens can be appropriately incident on the first lens through the opening of the reflecting member.

Furthermore, the light-emitting device according to claim 4 is the light-emitting device according to any one of claims 1 to 3, wherein the third lens has a flat surface on the side facing the light source, and The surface on the side facing the first lens is formed in a convex shape or a Fresnel shape.
In the light emitting device according to claim 4, by applying, for example, a Fresnel lens as the third lens, parallel light to be incident on the first lens can be suitably created.

Furthermore, the light-emitting device according to claim 5 is the light-emitting device according to any one of claims 1 to 4, wherein the first lens and the second lens are configured by a single fly-eye lens. It is characterized by being.
In the light-emitting device according to claim 5, since the two types of optical functions obtained by the first and second lenses of the lens body are realized by a single fly-eye lens, the light-emitting device body can be thinned. In addition to this, it is possible to appropriately irradiate the desired range with light.

  According to the first aspect of the present invention, the light emitted from the light source is aligned as a light beam parallel to the optical axis, and the parallel light is imaged and then projected onto the infinity surface. Can be improved. Furthermore, according to the first aspect of the present invention, since the light source image is formed in the front stage of the second lens functioning as the projection lens, the influence of the variation in the luminance distribution of the light source that is conjugate with the second lens is affected. However, it does not appear directly on the irradiated surface, the influence of uneven illuminance on the irradiated surface can be reduced, and the illuminance distribution on the irradiated surface can be made uniform.

  According to the second aspect of the present invention, all the light emitted from the light source is made parallel light and efficiently incident on the first lens while the third lens and the reflecting member cooperate. Since this can be emitted through the second lens, the light extraction efficiency can be improved.

  Furthermore, according to the light emitting device of the third aspect, the parallel light emitted from the rear stage of the third lens can be appropriately incident on the first lens through the opening of the reflecting member. As in the case of the invention, the light extraction efficiency can be improved.

  According to the light emitting device of the fourth aspect, by applying, for example, a Fresnel lens as the third lens, the parallel light to be incident on the first lens can be suitably created, and the obtained parallel light is the first lens. The light can be guided to the first and second lens sides.

  According to the light emitting device of the fifth aspect, since the two types of optical functions obtained by the first and second lenses are realized by a single fly-eye lens, the light is appropriately emitted within a desired range. In addition to being able to irradiate, it is possible to reduce the thickness of the main body of the apparatus, whereby a useful light-emitting device can be obtained.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view illustrating a configuration of a light-emitting device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of an LED lamp included in the light-emitting device. Further, FIG. 3 is a diagram illustrating a light guide path of light guided in the light emitting device, and FIG. 4 is a diagram for explaining a layout of each component of the light emitting device.

  As shown in FIG. 1, the light emitting device 1 of the present embodiment is mainly composed of an LED lamp 3, an optical component unit 12 that functions as a light control means, and a single fly-eye lens 7. The fly-eye lens 7 includes a plurality of incident surface side lens portions 7a arranged in a cell (matrix) functioning as a first lens, and a plurality of output surface side lens portions 7b arranged in a cell shape functioning as a second lens. Is provided.

  The LED lamp 3 is a light source that emits light in which different wavelength components are mixed. As shown in FIG. 2, the LED lamp 3 includes a base material 23 having a recess 22 and a light emitting element (light emitting diode element) 28. The base material 23 is formed by sequentially laminating, for example, a substrate 24, an insulating layer 25, a pair of electrode layers 26 (26a, 26b), and a recess forming member 27.

  The light emitting element 28 is provided in the recess 22 of the base material 23, and is bonded (die-bonded) on one electrode layer 26 a of the pair of electrode layers 6 with a conductive adhesive such as silver paste. Thereby, the lower electrode of the light emitting element 28 is connected to the electrode layer 26a. The upper electrode of the light emitting element 28 is connected to the other electrode layer 26b by a bonding wire 29 such as a gold wire.

  The light emitting element 28 is an LED chip that emits blue light by exciting phosphors with the emitted light to emit visible light. On the other hand, a phosphor layer 31 is formed in the recess 22 having a reflection surface on the inside. The phosphor layer 31 contains a yellow phosphor particle phosphor (particle) that is excited by blue light from the light emitting element 28 and emits yellow light. That is, the LED lamp 3 radiates white light from the radiation surface 3 a by mixing the blue light emitted from the light emitting element 28 and the yellow light emitted by the excitation of the phosphor layer 31. Here, as shown in FIG. 2, in such an LED lamp 3, since the path length of the blue light passing through the phosphor layer 31 differs depending on the emission angle of the light emitting element 28, white light is emitted from the emission surface 3a. Light of peripheral wavelengths is emitted in a slightly mixed manner.

  The optical component unit 12 aligns the light emitted from the LED lamp 3 with a light flux parallel to the optical axis, and is composed of the Fresnel lens 5 and the reflecting member 2 functioning as a third lens. As shown in FIGS. 1, 2, and 4, the Fresnel lens 5 is arranged so that the center position of the radiation surface 3a overlaps the incident surface side lens portion 7a of the fly-eye lens 7 and the focal position 3b. It is provided between the LED lamps 3. The surface of the Fresnel lens 5 facing the LED lamp 3 is flat, while the surface 5a facing the incident surface side lens portion 7a of the fly-eye lens 7 is formed in a thin annular Fresnel shape. . Thereby, the light radiated from the LED lamp 3 enters and emits parallel light. In addition, if it is a lens which can obtain parallel light in this way, you may form the surface of the side facing the entrance plane side lens part 7a of the fly eye lens 7 by convex shape.

  On the other hand, the reflecting member 2 surrounds the incident surface side lens portion 7a of the fly-eye lens 7 and the LED lamp 3 with a paraboloid 2a with reference to the focal position 3b, as shown in FIGS. And an opening 2b that opens to the entire incident surface side lens portion 7a. Further, the LED lamp 3 is attached to the reflecting member 2 through a light source support portion at a portion opposite to the light emitting surface 3a. Further, the Fresnel lens 5 is attached to the reflecting member 2 while its peripheral portion is held by a lens support member 8 made of a material such as highly translucent acrylic or glass. Further, the reflecting member 2 reflects the light emitted from the LED lamp 3 and not passing through the Fresnel lens 5 (for example, the light passing through the lens support member 8) by the parabolic surface 2a having a mirror finish, and becomes parallel light. To do.

  Here, as shown in FIG. 4, the Fresnel lens 5 is disposed at a position in contact with the conical virtual surface 5b connecting the inner peripheral edge of the opening 2b of the reflecting member 2 and the focal position 3b. A light beam parallel to the optical axis can be appropriately incident on the incident surface side lens portion 7 a of the fly-eye lens 7.

  As described above, the fly-eye lens 7 includes the entrance surface side lens portion 7a and the exit surface side lens portion 7b. The incident surface side lens unit 7 a collects (images) the parallel light emitted from the optical component unit 12. On the other hand, the exit surface side lens unit 7b projects the light collected by the entrance surface side lens unit 7a onto the infinity surface. That is, as shown in FIG. 3, the light emitted from the individual cellular lens portions of the exit surface side lens portion 7b spreads radially and irradiates the projection surface 9 while the light beams of the adjacent cellular lens portions overlap. Is done.

  Here, in the light-emitting device 1 of the present embodiment, light having a wavelength around white light is slightly mixed and emitted from the radiation surface 3a of the LED lamp 3 (light mixed with yellow light and blue light is emitted). Although the color unevenness is generated, the light source image is formed in the front stage of the exit surface side lens portion 7b, that is, the front stage of the projection lens. Therefore, the imaging portion (incident surface side lens) having a conjugate positional relationship with the LED lamp 3 is used. The position shifted from the imaging position of the portion 7a to the rear side is the irradiated surface (projection surface 9). Thereby, since the influence of the variation in the luminance distribution of the LED lamp 3 itself does not appear directly on the irradiated surface, the influence of the illuminance unevenness on the irradiated surface is reduced, and a uniform illuminance distribution is obtained on the projection surface 9. be able to.

  As described above, in the light emitting device 1 according to the present embodiment, the light emitted from the LED lamp 3 and radially spread is first collected as a light flux parallel to the optical axis through the optical component unit 12, and further this parallel light is Since an image is formed on the incident surface side lens portion 7a of the eye lens 7 and then projected onto the infinity surface, the influence of uneven illuminance can be reduced as described above, and the light extraction efficiency can be increased.

  Although the present invention has been specifically described above by the embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. For example, in the embodiment described above, white light is obtained by an LED lamp including a light emitting element that emits blue light and a phosphor layer that is excited by blue light and emits yellow light. For example, an LED lamp that obtains white light emission from an RGB phosphor layer and an ultraviolet light emitting type light emitting element may be applied as the light source of the light emitting device of the present invention.

Sectional drawing which shows the structure of the light-emitting device which concerns on embodiment of this invention. Sectional drawing of the LED lamp with which the light-emitting device shown in FIG. 1 is provided. The figure which shows the optical path of the light guided within the light-emitting device of FIG. FIG. 3 is a diagram for explaining a layout of each component of the light emitting device illustrated in FIG. 1.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Light-emitting device, 2 ... Reflective member, 2a ... Parabolic surface, 2b ... Opening part, 3 ... LED lamp, 3a ... Light-emitting surface, 3b ... Focus position, 5 ... Fresnel lens, 5b ... Virtual surface, 6 ... Light source support 7, a fly-eye lens, 7 a, an incident side lens unit, 7 b, an exit side lens unit, 9, a projection surface, 12, an optical component unit, 28, a light emitting element, 31, a phosphor layer.

Claims (5)

A light source that emits light with different wavelength components;
Light control means for making the light emitted from the light source parallel to the optical axis;
A lens body having a first lens for condensing the parallel light and a second lens for projecting the light collected by the first lens onto an infinite surface;
A light-emitting device comprising: The light control means includes
A third lens that is provided between the first lens and the light source disposed at a predetermined focal position and that receives light emitted from the light source and emits parallel light;
The light source and the first lens are surrounded by a paraboloid with respect to the focal position, and have an opening that opens to the first lens side. A reflecting member that reflects non-passing light on the paraboloid to make parallel light;
The light-emitting device according to claim 1.   3. The light emitting device according to claim 1, wherein the third lens is disposed at a position in contact with a conical virtual surface connecting an inner peripheral edge of the opening of the reflecting member and the focal position. apparatus.   The surface of the third lens facing the light source is flat and the surface facing the first lens is formed in a convex shape or a Fresnel shape. The light emitting device according to any one of 1 to 3.   5. The light-emitting device according to claim 1, wherein the first lens and the second lens are configured by a single fly-eye lens.

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