JP2012204214A - Illumination device and illumination instrument equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illumination device enabled to uniformly irradiate a light guide plate with light as a whole, without giving rise to increase of the number of light sources or processing of the light guide plate, as well as an illumination instrument equipped with the same.SOLUTION: The illumination device 10 includes a flat-plate light guide plate 13 and LEDs 33a, 33b arranged at a rear-face side of the light guide plate 13. Emission light from the LEDs 33a, 33b is made incident into the light guide plate 13, and the incident light is made totally reflected and guided at the inside of the light guide plate 13 and is made irradiated from a surface side of the light guide plate 13. An optically coupling member 35 for coupling the emission light from the LEDs 33a, 33b to make light incident aslant to the light guide plate 13 is provided between the light guide plate 13 and the LEDs 33a, 33b. The LEDs 33a, 33b are so arranged to emit light of color temperatures of 2,000 K to 6,000 K toward the optically coupling member 35, and that, for an optical axis direction of the emission light toward the optically coupling member 35 to cross the light guide plate 13.

Description

  The present invention relates to an illumination device that emits light from a light source in a planar shape by a light guide plate, and an illumination device including the illumination device.

  Conventionally, in an illuminating device, an LED (Light Emitting Diode) capable of saving energy by using low power consumption and low heat generation is used instead of an incandescent bulb. That is, since much of the supplied power is used for light emission, that is, the light emission efficiency is high, the LED lighting requires less power to produce the same brightness as the conventional incandescent lighting. In addition, the low power consumption is characterized by the fact that less heat is generated for the power that has been lost as heat in the prior art, and the lighting apparatus has a low heat generation.

  In recent years, lighting fixtures using LEDs have emerged not only for LED bulbs that replace incandescent bulbs but also for ceiling lights that are fixed to the ceiling.

  For example, Patent Literature 1 discloses a lighting fixture that can illuminate a ceiling surface by emitting light toward the side and back of the fixture body using LEDs.

  The lighting fixture 100 disclosed in Patent Document 1 is a ceiling-mounted ceiling light for home use. As shown in FIGS. 12 (a) and 12 (b), the fixture main body 110 and the front surface of the fixture main body 110 are provided. And a light-transmitting cover 101 that covers the side surfaces, and a light control body 102 that emits light from the peripheral edge portion 101a of the light-transmitting cover 101 toward the side and back of the instrument main body 110.

  And the instrument main body 110 is equipped with the light emitting module 120 which has several LED, and the lighting device 111 which lights LED. As shown in FIGS. 12C and 12D, the light emitting module 120 includes a base 121, a plurality of LED chips 122a mounted on the base 121, and yellow fluorescence excited by the LED chips 122a. And a semiconductor light emitting element 122 configured to emit white light with high luminance and high output.

  With this configuration, it is possible to provide a lighting fixture 100 that can radiate light toward the side and back of the fixture main body 110 to brighten the ceiling surface.

  By the way, in this kind of lighting fixture 100, since the several light emitting module 120 is arrange | positioned and arrange | positioned substantially on the front surface of the ceiling light, the number of the semiconductor light emitting elements 122 increases and it becomes high-cost.

  In order to solve this problem, for example, Patent Document 2 discloses a technique used for a backlight of a liquid crystal display device.

  As shown in FIG. 13, the backlight 200 for a display device disclosed in Patent Literature 2 is provided with a light emitting diode 201 below the light guide plate 210 so that its optical axis is orthogonal to the light guide plate 210. . Then, immediately above the light emitting diode 201 on the surface of the light guide plate 210, curved reflecting surfaces 211 and 211 are formed so as to reflect light from the light emitting diode 201 toward both ends of the light guide plate 210. A reflective sheet 202 is provided below the light emitting diode 201.

  With the above configuration, the number of the light emitting diodes 201 can be reduced because the light emitting diodes 201 need only be disposed on the center line of the light guide plate 210.

JP 2010-140797 A (published on June 24, 2010) JP 2006-49324 A (published February 16, 2006)

  However, in the display device backlight 200 disclosed in the above-described conventional Patent Document 2, the light guide plate 210 must be formed with reflecting surfaces 211 and 211 having curved surfaces. Therefore, since the light guide plate 210 has to be processed, the cost increases, and in particular, the processing of the large light guide plate has a problem that the area is large and difficult.

  Further, in the backlight 200 for a display device disclosed in Patent Document 2, the amount of light emitted to the liquid crystal panel side becomes too large immediately above the light emitting diode 201 in the light guide plate 210, and is uniform over the entire light guide plate. There is a problem that irradiation is difficult.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide an illumination device that enables uniform irradiation over the entire light guide plate without increasing the number of light sources and processing the light guide plate. And providing a lighting device including the same.

  In order to solve the above-described problems, an illumination device according to the present invention includes a flat light guide plate and a light source disposed on the back side of the light guide plate, and causes light emitted from the light source to enter the light guide plate. An illumination device that irradiates light from the surface side of the light guide plate while totally reflecting and guiding the incident light inside the light guide plate, wherein the light source is incident on the light guide plate at an angle. An optical coupling member that couples light emitted from the light guide plate and the light source, the light source emits light having a color temperature of 2000 K to 6000 K toward the optical coupling member; and The optical axis direction of the emitted light toward the optical coupling member is arranged so as to be orthogonal to the light guide plate.

  According to said invention, the optical coupling member which couple | bonds the emitted light from a light source is provided between a light guide plate and a light source so that light may inject into a light guide plate diagonally. The light emitted from the light source on the back surface of the light guide plate is coupled to the light guide plate through the optical coupling member and is incident obliquely, and moves to the end of the light guide plate while totally reflecting inside the light guide plate. The total reflection condition is broken by the optical path conversion element, and the light is emitted to the surface side of the light guide plate.

  As a result, light can be irradiated from the entire surface of the light guide plate simply by arranging the light sources along the back surface of the optical coupling member. As a result, the number of light sources can be reduced as compared with the case where light sources are arranged on the entire back surface of the light guide plate.

  In the present invention, by providing an optical coupling member separate from the light guide plate, light is incident obliquely on the flat light guide plate and totally reflected inside the light guide plate to be guided to the whole. be able to. As a result, even if the light guide plate is not processed, incident light from the light source can be guided inside the light guide plate via the optical coupling member, and light can be irradiated uniformly from the light guide plate.

  Furthermore, in the present invention, the light source is arranged so that the optical axis direction of the emitted light toward the optical coupling member is orthogonal to the light guide plate. For this reason, since it is not necessary to make the arrangement of the light source oblique to the flat light guide plate, the arrangement of the light source is easy and the structure is simple.

  In the present invention, the light source emits light having a color temperature of 2000K to 6000K. For this reason, it can be appropriately used as a lighting device such as a ceiling light.

  Therefore, it is possible to provide an illuminating device that enables uniform irradiation of the entire light guide plate without increasing the number of light sources and processing the light guide plate.

  Moreover, in the illuminating device of this invention, the said optical coupling member can be provided in strip | belt shape.

  Thereby, it is not necessary to make the relationship between the optical coupling member and the light source 1: 1, and a plurality of light sources are covered with one optical member, so that the structure of the optical system can be simplified. In addition, since the light source can be provided along the optical coupling member, wiring of the light source is facilitated.

  In the configuration in which the optical coupling members are provided in a strip shape, the optical coupling members may be double rows. In this case, in particular, it is preferable to arrange symmetrically about the vertical or horizontal center line of the light guide plate so that the luminance distribution of the double-row optical coupling members is symmetrical. In addition, when the optical coupling members are in a double row, the luminance of the light emitted from the surface of the light guide plate may be arranged so that the luminance at the center of the flat light guide plate is higher than the luminance at the end of the light guide plate. desirable.

  Moreover, in the illuminating device of this invention, the said optical coupling member can be provided on the centerline of the vertical or horizontal direction in the said flat light-guide plate.

  This makes it possible to make the luminance symmetrical about the vertical or horizontal center line of the light guide plate. Therefore, it is possible to provide a lighting device suitable for the luminance distribution.

  Moreover, in the illuminating device of this invention, it is preferable that the said light source consists of several LED.

  As a result, the LED has lower power consumption and lower heat generation than the incandescent bulb, and can save energy.

  In order to solve the above-described problems, a lighting fixture according to the present invention includes the lighting device.

  According to said invention, the illumination apparatus provided with the illuminating device which enables uniform irradiation in the whole light-guide plate can be provided, without accompanying the increase in the number of light sources, and the process of a light-guide plate.

  As described above, in the lighting device of the present invention, the optical coupling member that couples the light emitted from the light source so that the light is incident obliquely on the light guide plate is provided between the light guide plate and the light source. The light source emits light having a color temperature of 2000 K to 6000 K toward the optical coupling member, and the optical axis direction of the emitted light toward the optical coupling member is orthogonal to the light guide plate. Are arranged in such a way.

  The lighting fixture of this invention is provided with the said illuminating device as mentioned above.

  Therefore, there is an effect that it is possible to provide an illuminating device including an illuminating device that enables uniform irradiation over the entire light guide plate without increasing the number of light sources and processing the light guide plate.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view illustrating a configuration of a main part of a lighting device in a ceiling light as a lighting device according to an embodiment of a lighting device including a lighting device according to the present invention. (A) is a perspective view from the surface side which shows the structure of the said ceiling light, (b) is a perspective view from the back surface side which shows the structure of the said ceiling light. It is a perspective view which shows the structure of the light source module in the said illuminating device. (A) is sectional drawing which shows the optical path when the light radiate | emitted from LED injects into a light-guide plate via the optical coupling member which has a paraboloid, (b) is principal part sectional drawing which shows the optical path near LED. It is. (A) is sectional drawing which shows the optical path when the light radiate | emitted from LED injects into a light-guide plate via the optical coupling member which has an elliptical surface, (b) is principal part sectional drawing which shows the optical path of LED vicinity. is there. (A) is sectional drawing which shows the optical path when the light radiate | emitted from two LED injects into a light-guide plate through the optical coupling member which has a paraboloid and an ellipsoid, and radiate | emits from the surface side of a light-guide plate, (B) is a perspective view which shows the strip | belt-shaped light source module provided in the back surface of the light-guide plate. (A) is a top view which shows the said light-guide plate, (b) is a graph which shows the luminance distribution on the string which passes along point A * B of (a). It is a top view which shows the total reflection conditions in the outer periphery of the light-guide plate which consists of a disk in the light which injected into the light-guide plate from the said light source module. (A) shows the structure of the modification of the said light-guide plate, Comprising: It is a top view which shows a rectangular light-guide plate, (b) is a top view which shows the light-guide plate which chamfered the rectangular corner | angular part, (C) is a top view which shows an elliptical light-guide plate, (d) is a top view which shows a rhombus-shaped light-guide plate. It is a perspective view which shows the structure of the modification of the light source module in the said illuminating device, Comprising: A frame-shaped light source module. It is sectional drawing which shows the toning illumination in the said illuminating device. (A) is sectional drawing which shows the structure of the conventional lighting equipment, (b) is a top view which shows the structure of the lighting equipment, (c) is sectional drawing which shows the structure of the illuminating device in the lighting equipment. (D) is a plan view showing the configuration of the illumination device. It is a cross section which shows the structure of the backlight applied to the conventional liquid crystal display device.

  One embodiment of the present invention will be described below with reference to FIGS.

  A configuration of a ceiling light as a lighting device including the lighting device of the present embodiment will be described with reference to FIGS. 1, 2A, 2B, and 3. FIG. FIG. 1 is a cross-sectional view showing a configuration of a main part of a lighting device in a ceiling light, FIG. 2 (a) is a perspective view showing the configuration of the ceiling light, and FIG. 2 (b) is a ceiling light. FIG. 3 is a perspective view from the rear surface side showing the configuration of FIG. 3, and FIG. 3 is a perspective view from the front surface side showing the configuration of the light source module. In the present specification, unless otherwise specified, the “front surface” direction is the direction of the light irradiation surface in the lighting device of the present invention, the “back surface” direction is the opposite direction, and the “side surface” direction is The direction is orthogonal to both the front surface direction and the back surface direction. That is, when the lighting device of the present invention is installed as a ceiling light on the ceiling, the “front surface” is the room (floor) side, and the “back surface” is the ceiling side.

  As shown in FIG. 2A, the ceiling light 1 includes, for example, a disk-shaped lighting device 10, and the disk-shaped lighting device 10 includes a frame 20 on the outer periphery thereof. On the back surface of the ceiling light 1, as shown in FIG. 2B, a light source module 30 is provided on the diameter of the disk. The diameter of the ceiling light 1 is, for example, 550 mm, and the thinnest part is, for example, 10 mm. In addition, about the shape and each dimension of the ceiling light 1, it is not restricted to this.

  As shown in FIG. 1, the illumination device 10 of the ceiling light 1 includes a diffusion sheet 11, a prism sheet 12, a light guide plate 13, and a light source module 30 in order from the surface side. A portion of the back surface of the light guide plate 13 where the light source module 30 is not provided is provided with a reflection sheet 14 and a back chassis 15 that are openings.

  As shown in FIG. 3, the light source module 30 is provided with a sheet-like heat sink 32 on a light source holder 31 formed in a strip shape. On the heat sink 32, for example, an LED as a light source is provided. LED substrates 34a and 34b on which (Light Emitting Diodes) 33a and 33b are mounted are provided. In the present embodiment, the LEDs 33a and 33b are used as the light sources. However, the present invention is not limited to this. For example, an organic EL light emitting element or an inorganic EL light emitting element can be used.

  Here, in the present embodiment, the LEDs 33a and 33b emit light having a color temperature of 2000K to 6000K. That is, red light in the morning sun or sunset has a color temperature of about 2000K, and sunlight has a color temperature of about 5000K to 6000K. In addition, in the light source used with the backlight of a liquid crystal display device, LED of color temperature 10000K-20000K is used, for example. A plurality of the LEDs 33a and 33b are provided in parallel in two rows.

  Next, an optical coupling member 35 is provided above the plurality of LEDs 33a and 33b.

  That is, as shown in FIG. 1, the ceiling light 1 of the present embodiment includes a light guide plate 13 that irradiates light on the surface side, a light coupling member 35 as an optical element that couples light to the light guide plate 13, and the above LEDs 33a and 33b that emit incident light to the optical coupling member 35, and the light guide plate 13, the optical coupling member 35, and the LEDs 33a and 33b are arranged in this order from the front surface side to the rear surface side of the lighting device 10. It consists of things. Therefore, the illuminating device 10 in the ceiling light 1 according to the present embodiment is a illuminating device 10 directly below the light source in which the LEDs 33 a and 33 b are provided below the light guide plate 13.

  Here, in the present embodiment, as shown in FIGS. 4 (a) and 4 (b), the optical coupling member 35 has a substantially semi-cylindrical cross section provided between the light guide plate 13 and the LEDs 33a and 33b, that is, a rod-like body. More specifically, it consists of a band-like body having a semicircular cross section. The material of the optical coupling member 35 is made of the same resin as that of the light guide plate 13. Specifically, as shown in FIG. 4A, the surface of the optical coupling member 35 on the light guide plate 13 side is a top flat surface 35a that abuts the flat light guide plate 13, and both end sides from the top flat surface 35a. Are composed of a suspended curved surface 35b and 35b.

  The drooping curved surfaces 35b and 35b can be, for example, a cross-sectional parabola shown in FIG. However, the present invention is not limited to this, and a cross-sectional ellipse may be used as shown in FIGS. In the present invention, a curved shape such as a bow having a top flat surface 35a, or a plane inclined obliquely from the top flat surface 35a is not limited to a parabola or a cross ellipse.

  The surface of the optical coupling member 35 opposite to the light guide plate 13 side, that is, the lower end of the optical coupling member 35 is a lower flat surface 35c as shown in FIG. Further, a concave portion 35 d is formed in the central portion on the lower end side of the optical coupling member 35. However, the present invention is not necessarily limited to this, and the recess 35d may not exist. That is, in the present embodiment, it is only necessary to secure an optical path to the light guide plate 13 for the light reflected by the suspended curved surfaces 35b and 35b, so that the portion that does not become the optical path can be cut out as a recess 35d. Thereby, cost reduction can be aimed at. It is also possible to provide a reflective sheet in the recess 35d. Thereby, irradiation from the light guide plate 13 on the top flat surface 35a to the surface side of the light guide plate 13 can be improved.

  The LEDs 33a and 33b are provided close to the optical coupling member 35 below the lower flat surfaces 35c and 35c of the optical coupling member 35, respectively. As shown in FIGS. 4B and 5B, these LEDs 33a and 33b are preferably present on the end side with respect to the focal position F of the suspended curved surfaces 35b and 35b having a cross-sectional parabola or a cross-sectional ellipse. Thereby, for example, as shown in FIG. 4A, for example, the light emitted from the LED 33 a is reflected by the drooping curved surface 35 b of the cross-sectional parabola of the optical coupling member 35, and the reflected light is flat at the top of the optical coupling member 35. It reaches the surface 35a, and enters the light guide plate 13 obliquely while maintaining the arrival direction. The light incident on the light guide plate 13 travels by being totally reflected inside the right side of the light guide plate 13 shown in FIG. 4A and colliding with a light scatterer which is an optical path changing unit (not shown). The angle of traveling through 13 is changed, the total reflection condition is broken, the light is emitted from the surface side of the light guide plate 13, and is emitted from the ceiling light 1 through the prism sheet 12 and the diffusion sheet 11. Note that the light emitted from the LED 33b also proceeds symmetrically with the light from the LED 33a, as shown in FIG.

  Such an optical path is the same in the optical coupling member 35 having an elliptical cross section shown in FIGS. Specifically, as shown in FIG. 5A, the light emitted from the LED 33 a is reflected by a hanging curved surface 35 b having an elliptical cross section of the optical coupling member 35, and the reflected light is a flat top surface of the optical coupling member 35. It reaches 35a, and enters the light guide plate 13 obliquely while maintaining the direction of arrival. The light incident on the light guide plate 13 travels by being totally reflected on the inner right side of the light guide plate 13 shown in FIG. 5A, and collides with a light scatterer which is an optical path changing unit (not shown). The angle of traveling inside is changed, the total reflection condition is broken, the light is emitted from the surface side of the light guide plate 13, and is emitted from the ceiling light 1 through the prism sheet 12 and the diffusion sheet 11. Note that the light emitted from the LED 33b also travels symmetrically with the light from the LED 33a, as shown in FIG.

  Thus, by making the shape of the hanging curved surfaces 35b and 35b in the optical coupling member 35 to be a cross-sectional parabola or a cross-sectional ellipse, the light emitted from the LEDs 33a and 33b is reflected by the drooping curved surfaces 35b and 35b having a cross-sectional parabola or a cross-sectional ellipse. Thus, the light can be efficiently combined and incident on the light guide plate 13 from the top flat surface 35a, and the illumination light can be emitted from the ceiling light 1 as shown in FIG. Incidentally, in the comparison between the cross-section parabola and the cross-section ellipse, the cross-section ellipse can be coupled so that the light is focused and incident on the light guide plate 13, so that the coupling efficiency can be increased.

  As a result, in the illuminating device 10 in the ceiling light 1 of the present embodiment, as shown in FIG. 6B, the strip-shaped light source module 30 is provided across the central portion, that is, the center line, of the disc-shaped ceiling light 1. Thus, as shown in FIG. 7 (a), the luminance distribution shown in FIG. 7 (b) is shown in the string passing through the points A and B that are about ± 1/3 of the radius in the X-axis direction from the center of the light guide plate 13. The light emitted from the light guide plate 13 can be obtained. As a result, the ceiling light 1 of the present embodiment can obtain a uniform and smooth luminance distribution.

  Here, the luminance distribution of the disk-shaped ceiling light 1 in the present embodiment will be described.

  That is, in the present embodiment, as shown in FIG. 8, in the disc-shaped light guide plate 13, the light P emitted from the light source module 30 provided on the center line reaches the outer peripheral end 13a. Here, since the light guide plate 13 of the present embodiment is made of, for example, an acrylic plate, the radial direction (normal direction to the tangent line Q) at the outer peripheral end 13a is orthogonal to the light source module 30 according to Snell's law. The angle θ formed by the direction is divided into a region S1 that is not totally reflected and regions S2 and S2 that are totally reflected with a boundary of about 42 degrees. The region S1 that is not totally reflected is a central side portion of the diameter, and the regions S2 and S2 that are totally reflected are both side portions of the diameter. For this reason, in the present embodiment, the brightness of the entire light guide plate 13 is further uniformed by adjusting the arrangement pattern of the light scattering portion which is an optical path conversion element (not shown).

  Moreover, in the illuminating device 10 of this Embodiment, as shown in FIG. 1, the light of LED33a * 33b is entered from the back surface of the light-guide plate 13. As shown in FIG. Here, in the backlight field of the liquid crystal display device, a side edge type backlight has been conventionally used. However, the light utilization efficiency of the conventional side edge type backlight is 75%. The light use efficiency of the lighting apparatus 10 of the present embodiment was 88%. Therefore, it can be seen that the illumination device 10 of the present embodiment is superior in light utilization efficiency than the conventional side-edge type backlight. That is, in the conventional side edge type backlight, the linear expansion accompanying the temperature rise in the longitudinal direction of the light guide plate is large, so it is necessary to provide a gap between the LED and the light guide plate. Since the light leaks from this gap, the light utilization efficiency could not be increased. In this regard, in the illumination device 10 of the present embodiment, the LEDs 33a and 33b are provided directly below the light guide plate 13, so that the expansion dimension is small even when the light guide plate 13 is thermally expanded. Therefore, since it is not necessary to provide a gap, the light utilization efficiency can be increased.

  As a result, in the illumination device 10 of the present embodiment, unlike the conventional side-edge type backlight, there is no light source at the end of the ceiling light 1 as shown in FIG. It is possible to provide the frame 20 directly at the end of the frame. As a result, surface light emission with a frame size of 6 mm or less is possible. Further, by forming the frame 20 from a transparent, translucent or milky white resin material, it is possible to emit light from the entire surface including the frame 20. By optimizing the shape and material of the frame 20, indirect illumination that emits light in the back surface direction is possible.

  By the way, in this Embodiment, although the illuminating device 10 becomes disk shape, for example, it is not necessarily this, As shown to Fig.9 (a)-(d), it can be set as various shapes. . Specifically, FIG. 9A shows a rectangular light guide plate 13, FIG. 9B shows a light guide plate 13 with rectangular corners chamfered, and FIG. 9C shows an elliptic light guide plate 13. FIG. 9D shows a diamond-shaped light guide plate 13.

  In this case, in the rectangular light guide plate 13 shown in FIG. 9A, the light quantity gradually increases in the light guide direction of the light from the light source module 30, that is, in the direction orthogonal to the light source module 30 extending in a strip shape (traveling direction). To decrease. For this reason, the distribution of the dot pattern of the light scattering portion can obtain a uniform luminance distribution from the light guide plate 13 to the surface side by increasing the number of dot patterns as it goes in the traveling direction. On the other hand, in the direction perpendicular to the light guide direction (vertical direction), the amount of light is constant, and as a result, the distribution of the dot pattern of the light scattering portion is also uniform.

  Further, in the light guide plate 13 whose corners of the rectangle shown in FIG. 9B are chamfered, the rectangular portion is the same as that in FIG. That is, the amount of light gradually decreases in the light guide direction (traveling direction) of light from the light source module 30. For this reason, the distribution of the dot pattern of the light scattering portion can obtain a uniform luminance distribution from the light guide plate 13 to the surface side by increasing the number of dot patterns as it goes in the traveling direction. In the direction perpendicular to the light guide direction (vertical direction), the amount of light is constant, and as a result, the dot pattern distribution in the light scattering portion is also uniform.

  On the other hand, in the chamfered portion of the rectangular corner, the light is totally reflected in the direction perpendicular to the light guide direction (vertical direction). As a result, in order to obtain a uniform luminance distribution from the light guide plate 13 to the surface side. Needs to reduce the dot pattern of the light scattering portion as it proceeds in the vertical direction.

  Furthermore, in the elliptical light guide plate 13 shown in FIG. 9C, the light quantity gradually decreases in the light guide direction (traveling direction) of the light from the light source module 30. For this reason, the distribution of the dot pattern of the light scattering portion can obtain a uniform luminance distribution from the light guide plate 13 to the surface side by increasing the number of dot patterns as it goes in the traveling direction. On the other hand, in the direction perpendicular to the light guide direction (vertical direction), the light is totally reflected. As a result, in order to obtain a uniform luminance distribution from the light guide plate 13 to the surface side, the light proceeds in the vertical direction. Accordingly, it is necessary to reduce the dot pattern of the light scattering portion.

  The prism sheet 12 is used for the purpose of hiding the dot print image. For this reason, it arrange | positions so that a prism surface may become the light-guide plate 13 side. It can be replaced with an optical sheet such as a diffusion sheet or a microprism sheet. The prism sheet 12 can be abolished by forming the printing surface of the light scattering portion dot pattern on the light guide plate 13 in the back surface direction.

  As the diffusion plate 11, one having a thickness of 1 mm to 2 mm is used. About 1.5 mm is preferable. In FIG. 1, the light guide plate 13, the prism sheet 12, and the diffusion plate 11 are in close contact with each other, but a spacer member (not shown) may be used to provide a space. For example, if a space of about 2 mm is maintained between the light guide plate 13 and the diffusion plate, the dot print image can be concealed even if the dot pattern print surface of the light scattering portion of the light guide plate 13 is formed in the surface direction. is there.

  Moreover, in the rhombus-shaped light guide plate 13 shown in FIG. 9D, the amount of light gradually decreases in the light guide direction (traveling direction) of the light from the light source module 30. For this reason, the distribution of the dot pattern of the light scattering portion can obtain a uniform luminance distribution from the light guide plate 13 to the surface side by increasing the number of dot patterns as it goes in the traveling direction. On the other hand, in the direction perpendicular to the light guide direction (vertical direction), the light is totally reflected. As a result, in order to obtain a uniform luminance distribution from the light guide plate 13 to the surface side, the light proceeds in the vertical direction. Accordingly, it is necessary to reduce the dot pattern of the light scattering portion.

  In addition, in this Embodiment, although the light source module 30 of the illuminating device 10 is provided in strip | belt shape, it does not necessarily restrict to this. For example, as shown in FIG. 10, it can be a ring shape that is a frame shape. Thus, by using the frame-shaped light source module 30 that follows the shape of the illumination device 10, it is possible to easily achieve uniform luminance.

  Further, in the light source module 30 of the present embodiment, as described above, in the light source module 30, two rows of LEDs 33 a and 33 b are provided along the longitudinal direction of the optical coupling member 35. Accordingly, by adjusting the color temperatures of the two rows of LEDs 33a and 33b, as shown in FIG. 11, dimming illumination is possible. Specifically, the LED 33a is daylight white, and the LED 33b is a light bulb color. This makes it possible to perform dimming illumination such as irradiating daylight on the outside of the ceiling light 1 and illuminating a light bulb color on the inside of the ceiling light 1.

  Further, in the present embodiment, the light source modules 30 are provided in one row, but the present invention is not limited to this, and a plurality of light source modules 30 may be provided. Thereby, improvement in brightness and dimming illumination are possible.

  In the light source module 30 of the present embodiment, as described above, in the light source module 30, two rows of LEDs 33a and 33b are provided along the longitudinal direction of the optical coupling member 35. Accordingly, by adjusting the color temperatures of the two rows of LEDs 33a and 33b, as shown in FIG. 11, dimming illumination is possible. Specifically, the LED 33a is daylight white, and the LED 33b is a light bulb color. This makes it possible to perform dimming illumination such as irradiating daylight on the outside of the ceiling light 1 and irradiating bulb light on the inside of the ceiling light 1.

  As described above, the illumination device 10 according to the present embodiment includes the flat light guide plate 13 and the LEDs 33a and 33b arranged on the back side of the light guide plate 13, and guides the emitted light from the LEDs 33a and 33b. The light is incident on the light plate 13, and the incident light is totally reflected inside the light guide plate 13 and irradiated from the surface side of the light guide plate 13 while being guided. And the optical coupling member 35 which couple | bonds the emitted light from LED33a * 33b so that light may incline with respect to the light-guide plate 13 is provided between the light-guide plate 13 and LED33a * 33b. The LEDs 33 a and 33 b emit light having a color temperature of 2000 K to 6000 K toward the optical coupling member 35, and are arranged so that the optical axis direction of the emitted light toward the optical coupling member 35 is orthogonal to the light guide plate 13. Has been.

  According to the above configuration, the light coupling member 35 is provided between the light guide plate 13 and the LEDs 33a and 33b so as to couple light emitted from the LEDs 33a and 33b so that light is incident on the light guide plate 13 obliquely. It has been. For this reason, the light emitted from the LEDs 33a and 33b on the back surface of the light guide plate 13 is coupled to the light guide plate 13 through the optical coupling member 35 and is incident obliquely, and is totally reflected inside the light guide plate 13 while being totally reflected. And the total reflection condition is broken at the light scattering part which is an optical path conversion element, and the light is emitted to the surface side of the light guide plate 13.

  As a result, it is possible to irradiate light from the entire surface of the light guide plate 13 simply by arranging the LEDs 33 a and 33 b along the back surface of the optical coupling member 35. As a result, the number of LEDs 33a and 33b can be reduced as compared with the case where the LEDs 33a and 33b are arranged on the entire back surface of the light guide plate 13.

  In the present embodiment, by providing a light coupling member 35 that is separate from the light guide plate 13, light is incident obliquely on the flat light guide plate 13 and totally reflected inside the light guide plate 13. Can be guided to the whole. As a result, even if the light guide plate 13 is not processed, incident light from the LEDs 33a and 33b is guided inside the light guide plate 13 via the optical coupling member 35, and the light is uniformly emitted from the light guide plate 13. be able to.

  Further, in the present embodiment, the LEDs 33 a and 33 b are arranged so that the optical axis direction of the emitted light toward the optical coupling member 35 is orthogonal to the light guide plate 13. For this reason, since it is not necessary to arrange LED33a * 33b diagonally with respect to the flat light-guide plate 13, arrangement | positioning of LED33a * 33b is also easy and a structure is simple.

  In the present embodiment, the LEDs 33a and 33b emit light having a color temperature of 2000K to 6000K. For this reason, it can be appropriately used as an illumination device such as the ceiling light 1.

  Therefore, it is possible to provide the lighting device 10 that enables uniform irradiation of the entire light guide plate 13 without increasing the number of LEDs 33a and 33b and processing the light guide plate.

  Moreover, in this Embodiment, it is not necessary to process the light-guide plate 13, and since light injects from the downward direction, the light-guide plate 13 and the ceiling light 1 can be reduced in thickness. Specifically, a certain amount of thickness is required for processing the light guide plate 13. In this case, for example, when an edge light type light guide plate is considered, if the light guide plate 13 is made thinner than the widths of the LEDs 33a and 33b, the optical coupling ratio is lowered, so that there is a limit to thinning. In this regard, in the present embodiment, if the light guide plate 13 is thinned, the ceiling light 1 is thinned. Moreover, since the material of the light guide plate 13 can be saved, the cost can be reduced. Further, since the LEDs 33a and 33b may be mounted so that their optical axes are perpendicular to the light guide plate 13, the assembly is simple. That is, in the case of the conventional edge light, since it is necessary to attach LED33a * 33b from a side surface, manufacture becomes a little difficult.

  Moreover, in the illuminating device 10 of this Embodiment, the optical coupling member 35 is provided in strip | belt shape.

  Thereby, it is not necessary to make the relationship between the optical coupling member 35 and the LEDs 33a and 33b 1: 1, and the plurality of LEDs 33a and 33b are covered with one optical member, so that the structure of the optical system can be simplified. . Further, since the LEDs 33a and 33b can also be provided along the optical coupling member 35, the wiring of the LEDs 33a and 33b is facilitated.

  In the configuration in which the optical coupling member 35 is provided in a strip shape, the optical coupling member 35 may be a double row. In this case, in particular, it is preferable to arrange them symmetrically with respect to the vertical or horizontal center line of the light guide plate 13 so that the luminance distribution of the double-row optical coupling members 35 is symmetrical. Further, when the optical coupling members 35 are in a double row, the luminance of light emitted from the surface of the light guide plate 13 is such that the luminance at the center of the flat light guide plate 13 is higher than the luminance at the end of the light guide plate 13. It is desirable to arrange in.

  Moreover, in the illuminating device 10 of this Embodiment, the optical coupling member 35 is provided on the centerline of the vertical or horizontal direction in the flat light-guide plate 13. As shown in FIG. This makes it possible to make the luminance symmetric about the vertical or horizontal center line of the light guide plate 13 as an axis. Therefore, it is possible to provide the lighting device 10 suitable for the luminance distribution.

  Moreover, in the illuminating device 10 of this Embodiment, the light source consists of several LED33a * 33b. Accordingly, the LEDs 33a and 33b have lower power consumption and lower heat generation than incandescent bulbs, and can save energy.

  Furthermore, the ceiling light 1 as the lighting fixture of the present embodiment includes a lighting device 10. Thereby, the ceiling light 1 provided with the illuminating device 10 which enables uniform irradiation in the whole light-guide plate 13 without the increase in the number of LED33a * 33b and the process of the light-guide plate 13 can be provided.

  In the illumination device 10 of the present embodiment, a back chassis 15 that is a flat chassis that holds the light guide plate 13 in a flat surface is provided below the light guide plate 13, and the back chassis 15 is guided. The optical plate holding surface has an opening at a portion where the optical coupling member 35 contacts the light guide plate 13, and the optical coupling member 35 and the LEDs 33 a and 33 b are located below the light guide plate holding surface of the back chassis 15.

  By adopting such a configuration, only the optical coupling member 35 and the LEDs 33a and 33b protrude on the back surface side of the light guide plate 13. Accordingly, it is possible to reduce the thickness of portions other than the optical coupling member 35 and the LEDs 33a and 33b. For this reason, the overall thickness can be reduced. Furthermore, by setting it as such a structure, it becomes excellent also in the surface of heat dissipation of LED33a * 33b. Moreover, since the back chassis 15 functions as a heat sink by connecting the light source module 30 to the back chassis 15, high heat dissipation performance can be obtained. As a result, the light emission efficiency of the LEDs 33a and 33b is also improved.

  Further, in the ceiling light 1 of the present embodiment, the LEDs 33 a and 33 b are arranged in two rows along the longitudinal direction of the optical coupling member 35. Specifically, the LEDs 33a and 33b are provided in two rows in parallel along the center line immediately below both ends of the lower end chord in the optical coupling member 35 having a semicircular cross section.

  Thus, when the light is incident on the light guide plate 13, the two rows of LEDs 33a and 33b emit light in opposite directions, so that the line passing through the midpoint between the two rows is axially symmetric, that is, both sides of the light coupling member 35, that is, the light guide. The light can be guided to both ends of the optical plate 13. When the line passing through the midpoint between the two rows coincides with the center line of the light guide plate 13, the light guide plate is guided to both ends of the light guide plate with the center line of the light guide plate 13 being axially symmetrical. A luminance distribution that is axially symmetric about the 13 center lines can be obtained. Therefore, the luminance distribution can be made uniform in the light guide plate 13 with a simple structure. That is, when the LED 23a is single, there is a possibility that the portion directly above the LED 23a does not transmit light and becomes a dark part. This can be supplemented with light from other LEDs 23b.

  Note that the backlight 200 for a display device disclosed in Patent Document 2 has a problem that the luminance directly above the light emitting diode 201 becomes brighter than the surroundings and bright lines are generated, so that a uniform luminance distribution cannot be created. However, this problem can be solved in the present embodiment.

  Moreover, the illuminating device 10 of this Embodiment can be applied to a large planar light source as it is, and the large ceiling light 1 can also be provided. Furthermore, since no member is required around the light guide plate 13, it can be applied to a larger ceiling light 1 by arranging them seamlessly.

  Furthermore, the present invention can be applied to wall lighting attached to a wall surface, a signboard, and the like.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and the embodiments can be obtained by appropriately combining the technical means disclosed in the embodiments. The form is also included in the technical scope of the present invention.

  The lighting device of the present invention and the lighting device including the lighting device can be applied to ceiling-mounted ceiling lights, wall surface lighting attached to wall surfaces, signboards, and the like. And as an application field, it can apply to various lighting fixtures, such as facilities, such as a store and an office, and business.

1 Ceiling light (lighting equipment)
DESCRIPTION OF SYMBOLS 10 Illuminating device 11 Diffusion sheet 12 Prism sheet 13 Light guide plate 14 Reflection sheet 15 Back chassis 20 Frame 30 Light source module 31 Light source holder 33a, 33b LED
35 Optical coupling member 35a Top flat surface 35b Hanging curved surface 35c Flat bottom surface

Claims (5)

A flat light guide plate, and a light source disposed on the back side of the light guide plate. The light emitted from the light source is incident on the light guide plate, and the incident light is totally reflected inside the light guide plate. An illumination device for irradiating from the surface side of the light guide plate while guiding light,
An optical coupling member that couples light emitted from the light source so that light is incident obliquely on the light guide plate is provided between the light guide plate and the light source;
The light source emits light having a color temperature of 2000K to 6000K toward the optical coupling member, and the optical axis direction of the outgoing light toward the optical coupling member is arranged to be orthogonal to the light guide plate. A lighting device characterized by that.   The lighting device according to claim 1, wherein the optical coupling member is provided in a strip shape.   The lighting device according to claim 1, wherein the optical coupling member is provided on a vertical or horizontal center line of the flat light guide plate.   The lighting device according to claim 1, wherein the light source includes a plurality of LEDs.   A lighting fixture comprising the lighting device according to any one of claims 1 to 4.