JP2012204217A - Lighting device and lighting fixture equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device with uniform luminance distribution of emission light.SOLUTION: The lighting device (a ceiling light) is provided with a flat-plate light guide plate 13 and LEDs 33 arranged at a rear-face side of the light guide plate 13, in which, emission light from the LEDs 33 is made incident into the light guide plate 13 and, the incident light, while it is totally reflected and guided through the inside of the light guide plate 13, 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 33 for letting light incident aslant toward the light guide plate 13 is extended in a band shape between the light guide plate 13 and the LEDs 33. A plurality of the LEDs 33 are arranged along the optically coupling member 35 so that an optical axis direction with the highest luminance of the emission light toward the optically coupling member 35 crosses the light guide plate 13, and at the same time, an intensity of incident light from the LEDs 33 into the optically coupling member 35 is set in accordance with a distance from an incident position of the incident light into the light guide plate 13 and an end part of the light guide plate 13 in an extended direction of the optically coupling member 35.

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 residential use. As shown in FIGS. 14 (a) and 14 (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. 14C and 14D, 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. 15, the backlight 200 for a display device disclosed in Patent Document 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 illuminating device having a uniform luminance distribution of emitted light and an illuminating device including the illuminating device.

  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 the outgoing light from the light guide plate and the light source is provided extending in a strip shape, and the light source has the highest luminance of the outgoing light toward the optical coupling member. A plurality of light coupling members are disposed along the strip-shaped optical coupling member so that the high optical axis direction is orthogonal to the light guide plate, and the intensity of incident light from the plurality of light sources to the optical coupling member is Incident position of incident light on the light guide plate in the extending direction of the optical coupling member It is characterized in that it is set according to the distance between the ends of the Kishirube light plate.

  According to the above invention, the light emitted from the light source below the light guide plate is incident on the light guide plate obliquely after being coupled to the light guide plate via the optical coupling member, and the end of the light guide plate is totally reflected inside the light guide plate. The total reflection condition is broken on the way, and the light is emitted from the surface side of the light guide plate. Here, when the shape of the light guide plate is other than a rectangle, the incident light to the optical coupling member may be totally reflected at the end of the light guide plate or may not be totally reflected depending on the incident position of the incident light. Therefore, in the region where the incident light is not totally reflected at the end portion of the light guide plate, the luminance is lowered as compared with the region where the incident light is totally reflected at the end portion of the light guide plate.

  On the other hand, the intensity of the incident light from the plurality of light sources to the optical coupling member is the distance between the incident position of the incident light to the light guide plate and the end of the light guide plate in the extending direction of the optical coupling member. It is set according to. Therefore, by making the intensity of the incident light corresponding to the region where the incident light is not totally reflected at the end portion of the light guide plate larger than the intensity of the incident light corresponding to the region where the incident light is totally reflected at the end portion of the light guide plate Compared to the conventional configuration in which the intensity of incident light from the optical coupling member is set to be substantially constant regardless of the incident position, the difference in luminance between these regions can be reduced. Therefore, it is possible to provide an illumination device with a uniform luminance distribution of emitted light.

  In the illuminating device of the present invention, the shape of the light guide plate is a disc shape, and the intensity of the incident light is from the central position of the light coupling member at the incident position of the incident light in the extending direction of the light coupling member. It is preferable to be approximately inversely proportional to the distance.

  In the above configuration, since the shape of the light guide plate is a disk shape, in the region corresponding to the vicinity of the center position of the light coupling member, the incident light from the light coupling member is not totally reflected at the end of the light guide plate, and the optical coupling is performed. In a region corresponding to a position away from the central position of the member, incident light from the light coupling member is totally reflected at the end of the light guide plate. Therefore, the luminance of the region corresponding to the vicinity of the central position of the optical coupling member is lower than the luminance of the region corresponding to a position away from the central position of the optical coupling member.

  On the other hand, since the intensity of the incident light is approximately inversely proportional to the distance from the central position of the optical coupling member to the incident position of the incident light in the extending direction of the optical coupling member, the central position of the optical coupling member The difference between the brightness of the area corresponding to the vicinity and the brightness of the area corresponding to the position away from the center position of the optical coupling member can be reduced. Therefore, the luminance distribution of the emitted light can be made more uniform.

  In the lighting device of the present invention, the arrangement density of the light sources depends on the distance between the position where the light emitted from the light sources enters the light guide plate and the end of the light guide plate in the extending direction of the light coupling member. Is preferably set.

  In the lighting device of the present invention, the arrangement density of the light sources is approximately the distance between the position where the light emitted from the light sources enters the light guide plate and the end of the light guide plate in the extending direction of the optical coupling member. It is preferably inversely proportional.

  That is, by setting the arrangement density of the light sources in the region where the incident light is not totally reflected at the end of the light guide plate, and setting the arrangement density of the light sources in the region where the incident light is totally reflected at the end of the light guide plate, The luminance distribution of the emitted light can be made uniform.

  In the illumination device of the present invention, the luminance of each of the light sources is determined by the distance between the position where the light emitted from the light source enters the light guide plate and the end of the light guide plate in the extending direction of the light coupling member. Accordingly, it is preferably set.

  In the illumination device of the present invention, the luminance of each of the light sources is determined by the distance between the position where the light emitted from the light source enters the light guide plate and the end of the light guide plate in the extending direction of the light coupling member. It is preferable to be approximately inversely proportional.

  That is, by setting the luminance of the light source in the region where the incident light is not totally reflected at the end of the light guide plate and setting the luminance of the light source in the region where the incident light is totally reflected at the end of the light guide plate, The luminance distribution can be made uniform.

  In the illuminating device of the present invention, the light source is preferably an LED.

  Since the LED has a small shape and a high illuminance, the LED is suitable as a light source for an illumination device.

  The lighting device of the present invention is characterized by including any one of the above lighting devices.

  As described above, the lighting device of the present invention includes a flat light guide plate and a light source disposed on the back side of the light guide plate, and makes light emitted from the light source incident on the light guide plate. An illumination device for irradiating light from the surface side of the light guide plate while totally reflecting light within the light guide plate and guiding the light from the light source so that the light is incident obliquely on the light guide plate. An optical coupling member for coupling the incident light is provided extending in a strip shape between the light guide plate and the light source, and the light source has an optical axis with the highest luminance of the emitted light toward the optical coupling member. A plurality of light coupling members are arranged along the strip-shaped light coupling member so that the directions thereof are perpendicular to the light guide plate, and the intensity of incident light from the plurality of light sources to the light coupling member is The incident position of the incident light to the light guide plate in the extending direction of the member and the light guide plate It is set according to the distance between parts.

  Therefore, there is an effect that it is possible to provide an illumination device having a uniform luminance distribution of emitted light.

It is sectional drawing which shows the structure of a ceiling light. (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 injecting into the light-guide plate from the said light source module. It is a top view which shows the example which arrange | positioned LED equally. It is a top view which shows the example which set the arrangement | positioning density of LED suitably. It is a top view which shows an example of the light emission state of LED at the time of making the electric current sent through LED arrange | positioned equally differ from each other. (A) is a top view which shows the light-guide plate which chamfered the rectangular corner | angular part, (b) is a top view which shows an elliptical light-guide plate, (c) is a top view which shows a rhombus light-guide plate. 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 LEDs 33a and 33b are provided in parallel in two rows, and 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.

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

  That is, in this 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 (end portion) 13a. Here, since the light guide plate 13 of the present embodiment is made of, for example, an acrylic plate, the angle formed by the radial direction at the outer peripheral end 13a and the direction orthogonal to the light source module 30 is approximately 42 degrees according to Snell's law. Is divided into a region S1 that is not totally reflected and regions S2 and S2 that are totally reflected. 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.

  The reason why such a luminance distribution occurs will be described with reference to FIG. As shown in FIG. 8, the light emitted from the light source unit 30 propagates in a direction substantially perpendicular to the extending direction of the light source unit 30 while totally reflecting the light emitting surface side and the back surface side of the light guide plate 13. Then, as shown in FIG. 8, the angle formed between the traveling direction P of the light incident on the light guide plate 13 from the light source unit 30 in the in-plane direction of the light guide plate 13 and the tangent line Q of the peripheral portion 13 a of the light guide plate 13. In the region where is more than the critical angle θ, the light reaching the peripheral portion 13a of the light guide plate 13 is totally reflected by the peripheral portion 13a and further propagates in the light guide plate 13. On the other hand, in the region less than the critical angle θ, the light that has reached the peripheral portion 13 a of the light guide plate 13 is emitted from the peripheral portion 13 a to the outside of the light guide plate 13.

The critical angle θ is expressed by sin θ = 1 / n, where n is the refractive index of light propagating through the light guide plate 13 on the surface of the light guide plate 13 (a contact surface with air). In this embodiment, the light guide plate 13 made of acrylic is used, and the refractive index n of acrylic is about 1.49, so that the critical angle θ = sin ⁻¹ (1 / n) ≈42.2 °. .

  Here, as shown in FIG. 9, when the LEDs 33 are evenly arranged on the LED substrate 34 and the intensity distribution in the extending direction of the optical coupling member 35 of the light emitted from the optical coupling member 35 is constant. As shown in FIG. 7B, the luminance in the region S1 that is not totally reflected is lower than the luminance in the regions S2 and S2 that are totally reflected. For this reason, in the present embodiment, in order to make the luminance of the entire light guide plate 13 uniform, the arrangement density of the LEDs 33 is a position where the light emitted from the LEDs 33 enters the light guide plate 13 in the extending direction of the optical coupling member 35. And the distance from the end of the light guide plate 13 is set.

  Specifically, as shown in FIG. 10, the arrangement density of the LEDs 33 corresponding to the vicinity of the central position of the optical coupling member 35 is maximized, and the arrangement density of the LEDs 33 is decreased as the distance from the central position is increased. Thereby, the intensity of incident light from the plurality of LEDs 33 to the optical coupling member 35 is substantially inversely proportional to the distance from the central position of the optical coupling member 35 at the incident position of the incident light in the extending direction of the optical coupling member 35. .

  As shown in FIG. 8, at a position away from the center position of the light coupling member 35, the light incident on the light guide plate 13 from the LED 33 is totally reflected at the outer peripheral end 13 a of the light guide plate 13. In the vicinity of the position, the light incident on the light guide plate 13 from the LED 33 is not totally reflected at the outer peripheral end 13 a of the light guide plate 13. Therefore, a more uniform and smooth luminance distribution can be obtained by making the arrangement density of the LEDs 33 corresponding to the vicinity of the central position of the optical coupling member 35 larger than the arrangement density of the LEDs 33 corresponding to the position away from the central position. Can do.

  In this way, the arrangement density of the LEDs 33 is appropriately set, and the luminance of the incident light from the LED 33 corresponding to the region S1 that is not totally reflected is higher than the luminance of the incident light from the LED 33 corresponding to S2 and S2 that is totally reflected. By doing so, the luminance of the entire light guide plate 13 is made uniform.

  In the above, the intensity of the incident light from the optical coupling member 35 is changed by changing the arrangement density of the LEDs 33, but the present embodiment is not limited to this. For example, the intensity of incident light from the optical coupling member 35 may be changed by controlling the current flowing through each LED 33.

  Specifically, as shown in FIG. 11, with respect to the LEDs 33 that are evenly arranged on the LED substrate 34, the current flowing through the LEDs 33 corresponding to the central position of the optical coupling member 35 is maximized, and as the distance from the central position increases, The current flowing through the LED 33 is reduced. More specifically, the luminance of each LED 33 is approximately inversely proportional to the distance between the position where the light emitted from the LED 33 enters the light guide plate 13 and the end of the light guide plate 13 in the extending direction of the light coupling member 35. To be controlled. As a result, the intensity of incident light from the optical coupling member 35 becomes maximum at the central position of the optical coupling member 35 and decreases as the distance from the central position increases, and the luminance distribution of the outgoing light from the light guide plate 13 can be made uniform. it can.

  In addition, although the electric current of each LED33 may be controlled, you may control the electric current of LED33 per LED board 34 unit. In this case, the sizes of the LED boards 34 may be different from each other.

  With the above configuration, the luminance distribution can be made uniform while power consumption is suppressed.

  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.12 (a)-(c), it can be set as various shapes. . Specifically, FIG. 12A shows a light guide plate 13 with chamfered rectangular corners, FIG. 12B shows an elliptical light guide plate 13, and FIG. 12C shows a rhombus light guide plate 13. is there.

  Moreover, the light quantity of the illuminating device 10 is appropriately set according to the size of the room in which the illuminating device 10 is installed. For example, if you want to obtain an illuminance of 300 lux directly below, an illuminance of 50 lux at the corner of a room, the total luminous flux is 5100 lumens or more in a 12 tatami room, 3400 lumens or more in an 8 tatami room, and 2350 lumens or more in a 6 tatami room. Is required.

  Moreover, in this Embodiment, although the light source module 30 was provided in 1 row, it does not necessarily need to be this and may be in multiple rows. Thereby, improvement in brightness and dimming illumination are possible.

  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. Therefore, by adjusting the color temperatures of the two rows of LEDs 33a and 33b, toned illumination is possible as shown in FIG. Specifically, the LED 33a is daylight white, and the LED 33b is a light bulb color. Thereby, it is possible to perform tonal illumination such as irradiating daylight white light outside the ceiling light 1 and illuminating a light bulb color inside the ceiling light 1. It is also possible to use a dimming illumination that controls the amount of light for each region. For example, only the inner region can be made to emit light with a low luminance so as to have a nightlight function.

  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 a ceiling-mounted ceiling light or 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.

DESCRIPTION OF SYMBOLS 1 Ceiling light 10 Illuminating device 11 Diffusion sheet 12 Prism sheet 13 Light guide plate 13a Outer peripheral edge 14 Reflective sheet 15 Back chassis 20 Frame 30 Light source module 31 Light source holder 32 Heat sink 33 LED
33a LED
33b LED
34 LED board 34a LED board 34b LED board 35 Optical coupling member 35a Top flat surface 35b Hanging curved surface 35c Bottom flat surface 35d Recess

Claims (8)

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 extending in a strip shape between the light guide plate and the light source,
A plurality of the light sources are arranged along the strip-shaped optical coupling member such that the optical axis direction with the highest luminance of the emitted light toward the optical coupling member is orthogonal to the light guide plate,
The intensity of incident light from the plurality of light sources to the optical coupling member is
An illumination device, wherein the lighting device is set according to a distance between an incident position of incident light on the light guide plate and an end of the light guide plate in the extending direction of the optical coupling member. The shape of the light guide plate is a disc shape,
2. The illumination device according to claim 1, wherein the intensity of the incident light is approximately inversely proportional to a distance from a center position of the optical coupling member at an incident position of the incident light in an extending direction of the optical coupling member. . The arrangement density of the light sources is
2. The optical coupling member is set in accordance with a distance between a position where light emitted from the light source enters the light guide plate and an end of the light guide plate in the extending direction of the light coupling member. Or the illuminating device of 2. The arrangement density of the light sources is
4. The illumination according to claim 3, wherein in the extending direction of the optical coupling member, the light emitted from the light source is substantially inversely proportional to the distance between the position where the light is incident on the light guide plate and the end of the light guide plate. apparatus. The brightness of each of the light sources is
2. The optical coupling member is set in accordance with a distance between a position where light emitted from the light source enters the light guide plate and an end of the light guide plate in the extending direction of the light coupling member. Or the illuminating device of 2. The brightness of each of the light sources is
6. The illumination according to claim 5, wherein the light emitted from the light source in the extending direction of the optical coupling member is substantially inversely proportional to the distance between the position where the light emitted from the light source enters the light guide plate and the end of the light guide plate. apparatus.   The lighting device according to claim 1, wherein the light source is an LED.   An illumination apparatus comprising the illumination device according to claim 1.