JP5597091B2 - Lighting device - Google Patents

Description

  The present invention particularly relates to an illumination device that irradiates an irradiated surface.

  2. Description of the Related Art Conventionally, lighting devices that irradiate illuminated surfaces such as billboards for advertising characters or pictures, or liquid crystal televisions, and general illumination that emits light in a planar shape are known. In such a conventional illuminating device, the light emitting units including the light emitting element and the light flux controlling member (diffuse lens) are arranged in a matrix (for example, Patent Document 1, FIG. 14). The light emitting element is a light emitting diode (LED), for example, and emits light. The light flux controlling member receives light emitted from the light emitting element, and diffuses and emits the incident light.

  Such an illuminating device emits light emitted from a plurality of light emitting units in a planar state in a state where the light is diffused by a diffusion plate, and a film or a plate as an illumination target member is illuminated on the back side by the planar emitted light. Illuminate from. Moreover, such an illuminating device may utilize the light radiate | emitted in the planar shape as room illumination.

  For such an illuminating device, it is required to reduce power consumption while maintaining the brightness on the irradiated surface and the light emission quality of the planar illumination. As a method for satisfying this requirement, in the light flux controlling member, the light traveling direction is controlled so as to diffuse the incident light as much as possible, and the light emitted from one light emitting element is irradiated to a wide range of the irradiated surface. It is conceivable to increase the pitch between the light emitting units to reduce the number of light emitting units per unit area.

JP 2007-48883 A

  However, as the angle of the light emission direction from the light flux controlling member with respect to the optical axis of the light emitting element increases, the incident angle to the surface of the diffuser plate that becomes the irradiated surface increases and the surface reflectance increases. The transmitted light is reduced, and the light use efficiency as illumination light is reduced. In addition, since the amount of light transmitted through the diffusion plate is small at a position corresponding to between the light emitting units, bright and dark illuminance unevenness occurs on the diffusion plate (outgoing surface side). Therefore, simply increasing the diffusion angle of the light emitted from the light flux controlling member leads to a decrease in light utilization efficiency and a decrease in light emission quality, so there is a limit to reducing the number of light emitting units.

  The present invention has been made in view of the above points, and effectively reduces the use efficiency of light by effectively using light having a large angle, and improves the brightness on the irradiated surface and the light emission quality of the planar illumination device. An object of the present invention is to provide an illumination device capable of reducing power consumption by reducing the number of light-emitting units while maintaining.

  The lighting device of the present invention has a bottom plate and a side wall rising from the bottom plate, and has a box-shaped housing having an opening formed by the side wall, an inner side of the housing, and an inner surface of the bottom plate. A mounting substrate to be attached, a light emitting element that emits light, and a light flux control member that diffuses light emitted from the light emitting element, a plurality of light emitting units mounted on the mounting substrate, and the light flux control member, A light control member that emits pre-conversion outgoing light emitted at an angle greater than a predetermined angle with respect to the optical axis of the light emitting element, and changes the traveling direction so as to be smaller than the predetermined angle; and A light diffusing member that is fixed to the opening portion of the housing and closes the opening portion of the housing, and has a light transmissive property, and the light control member has the lower surface facing the bottom plate. Mounting board Is formed such that the height of the pre-conversion exit light is closer to the diffusion member than the exit position on the light exit surface of the luminous flux control member, and a prism is formed on the lower surface. take.

  ADVANTAGE OF THE INVENTION According to this invention, the fall of the utilization efficiency of light can be prevented by using effectively the light with a big emitted angle with respect to the optical axis of a light emitting element. Thereby, the number of light emitting units can be reduced and the power consumption can be reduced while maintaining the brightness on the irradiated surface and the light emission quality of the planar illumination.

The top view of the illuminating device in one embodiment of this invention AA line sectional view and illuminance distribution image diagram of FIG. Cross-sectional view and illuminance distribution image of a conventional lighting device Sectional view and illuminance distribution image of a conventional lighting device using a light flux controlling member The top view of the light control member concerning one embodiment of the present invention The top view of the illuminating device in one embodiment of this invention (modification 1) The top view of the illuminating device in one embodiment of this invention (modification 2) The top view of the illuminating device in one embodiment of this invention (modification 3) The top view of the illuminating device in one embodiment of this invention (modification 4) The top view (modification) of the light control member concerning one embodiment of the present invention

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

(Configuration of lighting device)
Hereinafter, the configuration of a lighting apparatus according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2. FIG. 1 is a plan view of the lighting device 1. FIG. 1 shows a state in which a diffuse transmission unit 50 described later is removed. 2 is a cross-sectional view taken along line AA in FIG. 1 and an illuminance distribution image diagram. 2A is a cross-sectional view taken along line AA in FIG. 1, and FIG. 2B is an illuminance distribution image diagram on the diffuse transmission part 50. FIG.

  The illuminating device 1 is mainly composed of a housing 10, a mounting substrate 20, a light emitting unit 30, a light control member 40, and a diffuse transmission part 50.

  The housing 10 is a resinous housing formed by injection molding a resin material such as polycarbonate, and a storage space is formed by a bottom plate 11 having a square planar shape and four side walls 12 rising from the bottom plate 11. To do. The housing 10 has an opening formed by the edges of the four side walls 12. A support portion (not shown) that supports the mounting substrate 20 is provided on the inner surface of the bottom plate 11. In addition, the material of the housing | casing 10 is not limited to resin, Metals, such as aluminum, may be sufficient. Further, the inner surface of the housing 10 may be processed so as to enhance the reflectivity of the light emitted from the light emitting unit 30. Examples of the method include selection of a high reflection type injection molding material, attachment of sheet-like aluminum, electroless plating, or white coating.

  The mounting substrate 20 is formed in an elongated strip shape. The mounting substrate 20 is formed of an insulating material such as glass epoxy. A conductive circuit pattern (not shown) that is electrically connected to a conductive terminal (not shown) of the light emitting element 30 is formed on the surface of the mounting substrate 20. The light emitting units 30 are mounted on the mounting substrate 20 at a predetermined interval. The mounting substrate 20 is fixedly installed on the support portion of the housing 10. In the present embodiment, the number of light emitting units 30 (light emitting elements 31 and light flux controlling members 32) mounted on the mounting substrate 20 is not limited.

  The light emitting unit 30 is mainly composed of a light emitting element 31 and a light flux controlling member 32.

  The light emitting element 31 is, for example, a light emitting diode (LED). The light emitting element 31 is mounted on the mounting substrate 20 along the longitudinal direction of the mounting substrate 20 by soldering conductive terminals (not shown) to the conductive circuit pattern of the mounting substrate 20. . The light emitting element 31 emits light when supplied with power via the circuit pattern of the mounting substrate 20. The optical axis of the light emitting element 31 is perpendicular to the inner surface of the bottom plate 11. Note that the optical axis of the light emitting element 31 is a central axis of a three-dimensional light beam emitted from the light emitting element 31.

  The light flux controlling member 32 is made of, for example, a transparent resin material such as PMMA (polymethyl methacrylate), PC (polycarbonate), EP (epoxy resin), or transparent glass. The light flux controlling member 32 is a circular lens whose planar shape has a center on the central axis P1 (see FIG. 2). The light flux controlling member 32 is mounted on the mounting substrate 20 at a predetermined interval along the longitudinal direction of the mounting substrate 20 so that the central axis P1 coincides with the optical axis of the light emitting element 31. The light flux controlling member 32 changes the light distribution characteristic of the light emitted from the light emitting element 31 mainly by refraction of light on the incident surface and the light emitting surface of the light flux controlling member 32 and emits the light toward the irradiated surface 50b. In the illuminating device 1 in which only the light emitting element 31 is arranged without using the light flux controlling member 32, the light output surface 50 a of the diffusing and transmitting unit 50 has a position directly above the light emitting element 31 (in the optical axis direction of the light emitting element 31) compared to the others. Becomes brighter and the illuminance unevenness increases (see FIG. 3). In addition, the continuous line of FIG.3 (b) shows the illumination intensity distribution of each light radiate | emitted from each light emission unit 30 on the light-projection surface 50a. In order to suppress this uneven illuminance, the light beam near the optical axis of the light emitting element 31 is controlled by the light beam control member 32 so as to irradiate the irradiated surface 50b having a large area (see FIG. 4). In addition, the broken line of FIG.4 (b) shows the illumination intensity distribution of each light radiate | emitted from each light emission unit 30 on the light-projection surface 50a. Moreover, the continuous line of FIG.4 (b) shows the illumination intensity distribution of all the lights radiate | emitted from the several light emission unit 30 on the light-projection surface 50a.

  The light control member 40 is made of, for example, a transparent resin material such as PMMA (polymethyl methacrylate), PC (polycarbonate), EP (epoxy resin), or transparent glass. As shown in FIG. 2, the light control member 40 is fixed between the light emitting units 30 and the inner surface of the bottom plate 11. The light control member 40 is preferably fixed at a position equidistant from the four light emitting units 30 adjacent to each other, in other words, at the center of a circle passing through the four light emitting units 30 adjacent to each other. That is, it arrange | positions so that light may be supplemented to the low illumination intensity part in the illumination intensity distribution of FIG.4 (b). In addition, the broken line of FIG.2 (b) shows the illumination intensity distribution of each light radiate | emitted from each light emission unit 30 on the light-projection surface 50a. Moreover, the continuous line of FIG.2 (b) shows the illumination intensity distribution of all the lights radiate | emitted from the several light emission unit 30 on the light-projection surface 50a.

  The light control member 40 emits light (hereinafter simply referred to as “light having a large angle”) emitted from the light flux control member 32 at an angle larger than a predetermined angle (for example, 75 °) with respect to the optical axis of the light emitting element 31. It has a function of entering and exiting while changing the traveling direction so as to be smaller than the predetermined angle (see FIGS. 2A and 5E).

  The diffuse transmission part (diffusion plate) 50 is formed in a sheet shape or a flat plate shape with a resin material such as PMMA (polymethyl methacrylate) or PC (polycarbonate) having excellent light transmittance. The diffuse transmission part 50 is formed in a size substantially the same as the planar shape of a member to be illuminated such as a liquid crystal display panel, an advertisement display panel, or a sign display panel. The diffuse transmission part 50 is fixedly installed in the housing 10 so as to cover the opening, diffuses and transmits the light irradiated on the irradiated surface 50b, and emits the light from the light emitting surface 50a.

  The diffuse transmission part 50 is formed with fine irregularities (prism-like projections, irregularities formed by diffusion processing by embossing or bead coating) on the surface, or a diffusing material is mixed inside, so that the light flux controlling member The light emitted from 32 and the light control member 40 is diffused while being transmitted, and the light applied to the illuminated surface (not shown) such as the back surface of the liquid crystal is made uniform.

(Shape of light control member)
Next, the shape of the light control member 40 will be described with reference to FIG. FIG. 5 is a plan view of the light control member 40 according to the present embodiment. 5 (a) is a top view, FIG. 5 (b) is a front view, FIG. 5 (c) is a cross-sectional view taken along the line BB, FIG. 5 (d) is a cross-sectional view taken along the line CC, and FIG. It is an enlarged view of D section.

  As shown in FIG. 5, the light control member 40 includes a leg portion 41, a column portion 42, and a top plate portion 43.

  The leg portion 41 is provided to stably attach the light control member 40 to the bottom plate 11, and in the present embodiment, the bottom surface 44 that contacts the bottom plate 11 is formed in a flat surface. Note that the shape of the leg portion 41 is not particularly limited as long as the top plate portion 43 can be fixed so as to efficiently receive the light from the light emitting unit 30.

  The column part 42 is provided in order to set the distance between the bottom surface 44 of the leg part 41 and the lower surface 45 of the top plate part 43 to a predetermined value, and has a cross-sectional area within a range having sufficient strength. Is desirable to be small.

  The top plate portion 43 has a flat plate shape. When the light control member 40 is attached to the bottom plate 11, the lower surface 45 that faces the bottom plate 11 and the upper surface 46 that is the opposite surface of the lower surface 45 are substantially parallel to the bottom plate 11. In FIG. 3, the outer shape of the top plate portion 43 in plan view is formed to be substantially square, but the present invention is not limited to the outer shape of the top plate portion 43.

  The lower surface 45 is formed so that the cross section becomes the prism 47. In order to obtain the effect of the present invention, it is desirable that the apex angle of the prism 47 is 90 ° or less. In FIG. 5E, the apex angle of the prism 47 is 70 °. The apex angle of the prism 47 is such that the angle of the light reaching the upper surface 46 via the prism 47 with respect to the optical axis of the light emitting element 31 is smaller than the angle of the light reaching the lower surface 45 with respect to the optical axis of the light emitting element 31. Designed to. The apex angle of the prism 47 is adjusted by the amount of light reaching the lower surface 45 and the angle with respect to the optical axis of the light emitting element 31. Further, the apex angle of the prism 47 may be changed depending on the position of the lower surface 45. In FIG. 5, each ridge portion of the prism 47 in a plan view of the light control member 40 is formed in a square shape. However, the present invention is not limited to the shape of the prism. Each ridge may be formed in a circular shape. The prism 47 may be formed in a lattice shape.

  The height of the lower surface 45 of the light control member 40 from the mounting substrate 20 is diffused more than the emission position on the light emission surface of the light flux control member 32 that changes the traveling direction by the lower surface 45 when the light control member 40 is attached to the bottom plate 11. It is formed so as to be close to the transmission part 50. As a result, the light emitted from the light beam control member 32 emitted from the light beam control member 32 at a large angle with respect to the optical axis of the light emitting element 31 is incident from one surface of the prism 47 and is almost entirely emitted from the other surface. Reflected and emitted from the upper surface 46. In order to change the direction of more light into light that can be efficiently transmitted through the diffusing and transmitting portion 50, the lower surface 45 is placed at a position higher than the position at which the height of the light flux controlling member 32 is maximized from the mounting board 20. It is preferable to arrange.

  The upper surface 46 is formed in a plane. However, processing for forming fine irregularities on the surface of the upper surface 46 may be performed. By this processing, the light control member 40 can diffuse and emit the incident light while transmitting.

(Effect of this embodiment)
As described above, in the present embodiment, the light control member 40 is attached to the bottom plate 11 so as to be positioned between the light flux control members 32. When the light control member 40 is attached to the bottom plate 11, the lower surface 45 is formed so as to be closer to the diffuse transmission part 50 than the light exit surface of the light flux control member 32, and a prism is formed on the lower surface 45. The Thereby, the light emitted from the light flux controlling member 32 at a large angle with respect to the optical axis of the light emitting element 31 is emitted from the light controlling member 40 while changing the traveling direction so as to be smaller than the predetermined angle. As a result, the light emitted from the light control member 40 is transmitted without being reflected on the irradiated surface 50b of the diffuse transmission part 50 (see FIG. 2).

  Therefore, according to the present embodiment, it is possible to effectively use light having a large angle and prevent a decrease in light use efficiency. Thereby, the power consumption can be reduced by reducing the number of light emitting units while maintaining the brightness on the irradiated surface.

  Moreover, according to this Embodiment, the dark part which was made between the light emission units in the conventional illuminating device can be eliminated.

(Modification)
FIGS. 6 to 9 are diagrams showing modifications of the illumination device according to the present invention. 6 to 9, the same reference numerals as those in FIGS. 1 and 2 denote the same parts as in FIGS. 1 and 2, and a detailed description thereof will be omitted.

  FIG. 6 is a plan view of the lighting device 1a. In the lighting device 1a, the mounting substrate 20a is formed in a planar shape wider than the mounting substrate 20 of FIG. 1, and a plurality of light emitting units 30 are mounted in a matrix on the mounting substrate 20a. In FIG. 6, the light control member 40 is fixed between the light emitting units 30 on the mounting substrate 20 a.

  FIG. 7 is a plan view of the lighting device 1b. In the lighting device 1b, the bottom plate 11b has a circular planar shape, and a storage space is formed by the bottom plate 11b and a side wall 12b rising from the bottom plate 11b. The lighting device 1b has a shape suitable for use in ceiling lighting or the like.

  FIG. 8 is a plan view of the illumination device 1c. In the lighting device 1c, the same number of mounting substrates 20c as the light emitting units 30 are prepared, and one light emitting unit 30 is mounted on one mounting substrate 20c. In FIG. 8, the light control member 40 is fixed to the bottom plate 11 between the light emitting units 30 and in the vicinity of the outer edge where the amount of light is insufficient.

  FIG. 9 is a plan view of the lighting device 1d. FIG. 9A is a top view, and FIG. 9B is a side sectional view. In the lighting device 1d, the bottom plate 11d has a circular planar shape, and a storage space is formed by the bottom plate 11d and a side wall 12d rising from the bottom plate 11d. It is fixed. Further, in the lighting device 1d, the light control member 40d is formed in a circular shape in which the column portion 42d is formed in an annular shape along the inner peripheral surface of the side wall 12d, and the top plate portion 43d is formed in a circular shape having a through hole 48d in the center. The In the illuminating device 1d, the emitted light from the light flux controlling member 32 having an angle with respect to the optical axis in the range of 0 ° to a predetermined angle is directly caused to reach the irradiated surface of the diffusing and transmitting portion (diffusing plate) 50d. Further, in the illuminating device 1d, the light transmitted from the light beam control member 32 whose angle with respect to the optical axis is outside the predetermined angle range is changed in the traveling direction by the top plate portion 43d, and then the diffuse transmission portion (diffusion plate) 50d. To reach the irradiated surface.

  FIG. 10 is a view showing a modification of the top plate portion and the prism of the light control member 40 of the illumination device according to the present invention. In FIG. 10, the same reference numerals as those in FIG. FIG. 10A shows a case where the outer periphery of the top plate portion 43e is formed in a circular shape and each ridge portion of the prism 47e is formed in a square shape. FIG. 10B shows a case where the outer periphery of the top plate portion 43f and each ridge portion of the prism 47f are formed to be circular. FIG. 10C shows a case where the outer periphery of the top plate portion 43g and each ridge portion of the prism 47g are formed by four arcs having a predetermined diameter with the light emitting unit 30 (light emitting element 31) as the center.

  The illuminating device according to the present invention is suitable for use in the field of flat display using a backlight and general illumination that emits light in a planar shape.

DESCRIPTION OF SYMBOLS 1 Illuminating device 10 Housing | casing 11 Bottom plate 12 Side wall 20 Mounting board 30 Light emitting unit 31 Light emitting element 32 Light flux control member 40 Light control member 41 Leg part 42 Column part 43 Top plate part 44 Bottom face 45 Bottom face 46 Top face 47 Prism 50 Diffusing transmission part

Claims (3)

A box-shaped housing having a bottom plate and a side wall rising from the bottom plate, and having an opening formed by the side wall;
A mounting substrate attached to the inner side of the casing and the inner surface of the bottom plate;
A light emitting element that emits light and a light flux controlling member that diffuses the light emitted from the light emitting element, and a plurality of light emitting units mounted on the mounting substrate;
Pre-conversion emitted light that is arranged between the plurality of light emitting units and emitted from the light flux controlling member at an angle larger than a predetermined angle with respect to the optical axis of the light emitting element is incident on the inside, and the predetermined angle A light control member that emits toward the opening portion by changing the traveling direction to be smaller than
A diffusing member that is fixed to the opening portion of the housing and has a light diffusing property and a light transmitting property that closes the opening portion of the housing;
Comprising
The light control member has a lower surface facing the bottom plate that is closer to the diffusion member than a position on the light exit surface of the light beam control member on the light exit surface of the pre-conversion exit light from the mounting substrate. Formed as
A prism is formed on the lower surface,
Lighting device.   The lighting device according to claim 1, wherein one light emitting unit is mounted on one mounting substrate.   The lighting device according to claim 1, wherein a plurality of the light emitting units are mounted on one mounting board.

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