JP2011028997A - Surface light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface light-emitting device which is excellent in installation workability at low cost and uniformity of light emission, in the device where planar light emission is performed by transmitting light inside a light guide plate from the center to an outer periphery while an LED light source unit is arranged in the center of the light guide plate. <P>SOLUTION: Light-emitting elements are mounted on a rigid printed circuit board with no flexibility, a light source unit is formed by preparing the rigid printed circuit board in a polygonal shape, and the light source unit is stored in a recessed section formed at the center of the light guide plate. At this time, the light source unit is fixed in the light guide plate at the position relationship where straight sections forming the polygonal shape of the light source unit is parallel with sides constituting an outer peripheral edge of the light guide plate and they are also perpendicular to the diagonal line of the light guide plate. Further, through-holes for mounting are formed from the surface of the light guide plate to its back side, and their formation positions are prepared on lines where such extension lines are drawn on the surface of the light guide plate by connecting the center section and corner sections of the polygonal shape of the light source unit, fixed at the center of the light guide plate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a surface light-emitting device that is mounted inside an internally illuminated signboard and used as an illuminating body, and in particular, a module in which an LED light source, a light guide plate, and an LED driving power source are integrated can be arranged alone or in combination. In addition, the present invention relates to a surface light emitting device that can appropriately configure a light emission range as an illuminating body in accordance with the size of an internally illuminated signboard.

  Conventionally, fluorescent lamp light sources have been widely used in internally illuminated signboards. However, the service life of fluorescent lamps is generally as short as 6000 to 12000 hours. Compared to large pillar signs installed in convenience stores and suburban stores, and lighting signs installed around the store entrance (hereinafter referred to as facade signs). Since it is difficult to deal with a signboard attached to a high place every time the lamp runs out, a new fluorescent lamp is simultaneously replaced every certain period of time. For this reason, it is necessary to work at a high altitude in the middle of the night at a relatively high frequency of once a year, and there is also a waste of replacing a fluorescent lamp that has not reached the end of its life with a new one. Consideration for energy saving and environmental problems was required. Therefore, in recent years, a light emitting lamp device using an LED (light emitting diode) as a light source of an internally illuminated signboard and an edge light device that introduces LED light from one side of a light guide plate to emit light in a planar shape have been proposed.

  For example, Patent Document 1 discloses a flat illumination device used for a backlight of a liquid crystal device. According to this flat illumination device, the light emitted from the LED light source is incident on the inside of the light guide plate from the light incident portion formed on the side or center of the light guide plate, and the incident light is provided on the light guide plate while changing the arrangement density distribution. Reflecting with an element enables surface light emission with less luminance unevenness.

JP 2003-232933 A

  Since facade signs such as those mentioned above require a thinner depth dimension, the transition from fluorescent light sources to LED light sources is convenient not only in terms of energy saving and environmental issues, but also in terms of thinner and smaller devices. Can be said to be good. However, it is not suitable for the edge light device of the type that introduces light of LEDs arranged in a row from one side of the light guide plate into the inside of the light guide plate when trying to emit light uniformly with high brightness over a wide area. It was. This is because irradiating light from one side to a rectangular light guide plate enables efficient arrangement as a device configuration, while reaching the light with the same luminous efficiency from end to end of the light guide plate. Therefore, it is not suitable for applications in which a light guide plate having a fundamentally large size is surface-emitting.

  Therefore, as described in Patent Document 1, the LED light source unit is arranged at the center of the light guide plate, and the light is irradiated from the center toward the periphery of the light guide plate. Compared with the configuration in which the LED light source unit is provided on one side of the light guide plate, the size of the light guide plate that can be driven to emit light by one LED light source unit can be greatly increased. . However, the method of placing the LED light source unit in the center of the light guide plate has never been advantageous in terms of cost. In order to make the light guide plate emit light evenly, it is effective to irradiate light uniformly from the center of the light guide plate to the surrounding 360 °. Ideally, the LED lamp is applied to the outer peripheral surface of the cylindrical substrate. Although it is preferable to mount the light emitting range while overlapping the adjacent LEDs, a flexible substrate that is expensive in terms of cost is required for such a configuration. Also in the manufacturing process, it is necessary to align the LED mounted on the outer periphery of the cylindrical substrate and the light introducing portion of the light guide plate.

  And in any surface light emitting device of the method of placing the LED light source unit in the center of the light guide plate, or the method of providing the LED light source unit on one side of the light guide plate, a mounting member such as a rail member is previously attached at the time of installation work. Many structures are employed in which the surface light emitting device is fixed to the mounting member after being mounted. In terms of the labor required for the work, it is easy and desirable to fix the surface light emitting device through the surface side with the surface light emitting device in contact with the installation location. However, in such a structure, the screw insertion hole is guided. Since it passes through the optical plate and appears on the surface, there is a problem that the screw insertion hole affects the light transmitted through the inside of the light guide plate and uneven brightness tends to occur.

  The present invention has been made in response to the above-described problems, and an LED light source unit is arranged in the center of the light guide plate so that surface light is emitted by transmitting light from the center toward the outer periphery to the inside of the light guide plate. An object of the present invention is to provide a surface light emitting device that is low in cost, excellent in installation workability, and excellent in light emission uniformity.

  In order to achieve the above object, the present invention introduces light emitted from a light emitting element into the light guide plate from the end face of the light guide plate, and emits the introduced light from the surface of the light guide plate to emit light in a planar shape. The light emitting device includes a recess formed in the center of the light guide plate, and a light source unit including a plurality of light emitting elements accommodated in the recess, and the light source unit includes a plurality of rigid printed boards on which the light emitting elements are mounted. It is arranged in a polygon, and the mounting surface of the printed circuit board constituting the polygonal linear portion is parallel to the side of the light guide plate and is perpendicular to the diagonal line of the light guide plate. A surface light-emitting device is proposed in which light emitted from a light-emitting element that is fixed and mounted is introduced into the light guide plate from an end surface of the light guide plate facing the recess.

  The light guide plate is provided with an installation through-hole penetrating from the front surface of the light guide plate to the rear surface side in order to fix and install the light guide plate, and the position of the installation through hole is determined by the position of the light guide plate. It is desirable that it is on the surface of the light guide plate on the extension line connecting the polygonal central part and the polygonal corners of the light source unit fixed at the center.

  Further, the light guide plate is provided with a light source unit mounting through-hole penetrating from the front surface of the light guide plate to the rear surface side in order to fix the light source unit to the light guide plate. It is desirable that the position of the light guide plate is on the surface of the light guide plate on the extension line connecting the polygonal central portion and the polygonal corner portion of the light source unit fixed to the center of the light guide plate.

  According to the present invention, a light emitting element is mounted on a rigid printed circuit board that does not have flexibility, and the light source unit is configured by arranging the rigid printed circuit board on which the light emitting element is mounted in a polygonal shape, at the center of the light guide plate. It accommodates in the formed recessed part. At this time, the linear portion constituting the polygonal shape of the light source unit is fixed to the light guide plate in such a positional relationship that it is parallel to the side constituting the outer peripheral edge of the light guide plate and perpendicular to the diagonal line of the light guide plate. ing. By adopting such a configuration, it is possible to irradiate light uniformly around 360 ° from the center of the light guide plate toward the outer peripheral edge without using a flexible substrate, a surface that is low in cost and excellent in light emission uniformity. A light-emitting device can be provided.

  In addition, by forming an installation through hole in the light guide plate to fix and install the surface light emitting device at the installation location, the surface light emitting device can be fixed to the installation target position with screws from the surface of the light guide plate. This can greatly improve the installation workability. Furthermore, the formation position of the through hole for installation penetrating from the front surface to the back surface side of the light guide plate is connected to the surface of the light guide plate by connecting the central portion of the light source unit fixed to the center of the light guide plate and the polygonal corners. By providing the extension line on that line, the position of the through hole for installation can be placed in the area where the LED light irradiated while spreading from the adjacent linear part across the polygonal corner part overlaps. Even if the installation through hole blocks a part of the light transmitted through the light guide plate, it is compensated by the light traveling from a different direction from the blocked light, and the installation through hole causes a shadow of shading. Can be prevented. That is, it is possible to prevent uneven brightness from occurring while forming the installation through hole on the surface of the light guide plate.

  In addition, the light source unit is fixed to the light guide plate with screws or the like, and the light source unit mounting through hole for fixing the light source unit to the center of the light guide plate in the same way as the installation through hole and the polygonal shape. It is provided on the line which extended the line to the surface of the light guide plate. As a result, it is possible to prevent the light passing through the light source plate from the LED of the light source unit into the light guide plate and transmitting the light directly from the light source unit mounting through-hole. It is possible to prevent uneven brightness from being formed.

1 is an external view of a surface light emitting device according to an embodiment of the present invention. It is a block diagram which shows the internal structure of the surface emitting device which concerns on an Example of this invention. It is explanatory drawing which shows the principal part structure of this invention. It is explanatory drawing which shows the positional relationship of the through-hole for installation provided in a light-guide plate, and the through-hole for light source unit attachment.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings. FIG. 1 is an explanatory view showing the overall structure of a surface light emitting device according to an embodiment of the present invention, and FIGS. 1 (a), (b) and (c) show a plan view, a side view and a bottom view, respectively. Reference numeral 1 denotes a light guide plate, which is made of a transparent material such as methacrylic resin or acrylic resin, and has a square shape as a whole, and a recess 2 for accommodating the LED light source is formed at the center thereof. The plan view of FIG. 1A shows a state where an octagonal milk half-resin plate 3 is mounted in the recess 2 at the center of the light guide plate 1. Although not shown in FIG. 1, the concave portion 2 is formed in an octagonal shape in plan view, and the light source unit 4 is fitted and attached to the concave portion 2 from the back side of the light guide plate. 5 is fastened and fixed. Reference numeral 6 denotes a light reflecting sheet, which is attached to the back side of the light guide plate 1 so as to cover the entire surface. The light reflecting sheet is made of a fine foamed plastic material and has a characteristic of reflecting light while uniformly diffusing, and the light that enters the light guide plate 1 from the light source unit 4 is shown in FIG. It plays the effect of reflecting to the surface side. Reference numeral 7 denotes a reflective dot, a function as an adhesive paste for bonding the light guide plate 1 and the light reflection sheet 6, and a function to reflect and scatter light that has entered the light guide plate 1 from the light source unit 4 at the reflective dot portion. It has both functions. As shown in FIG. 1A, the pattern of the reflective dots is circular and is formed such that the diameter of the dots gradually increases as the distance from the LED irradiation portion of the light source unit 4 increases. As a result, the light irradiated from the light source unit 4 and transmitted through the inside of the light guide plate 1 to reach the reflection dots 7 is transmitted through the reflection dots 7 and reflected and scattered by the light reflection sheet 6 regardless of the light incident angle. Since the surface light is transmitted through the reflection dots 7, the light emission area ratio by the reflection dots 7 increases as the distance from the light source unit where the light transmitted through the light guide plate attenuates, and the luminance of the entire light emission surface is made uniform. Yes. The reflective dots 7 are formed by using a screen printing method or the like with an adhesive mainly composed of a transparent acrylic resin or the like. Reference numeral 10 denotes an installation through-hole penetrating from the front surface to the back surface of the light guide plate. In this embodiment, two positions are provided in the vicinity of each side corresponding to the outer periphery of the light guide plate, and further the center of the light guide plate in the vicinity of the light source unit 4. Four places are provided in the part, and a total of twelve through holes for installation are formed per light guide plate. This installation through-hole 10 is a hole for attaching this apparatus at the time of installation work, and it can be installed at the installation site by tightening with a surface light emitting device in contact with the installation location through a screw or the like from the surface side. Secure the device. Reference numeral 11 denotes a light source unit mounting through hole, which corresponds to the fixing mounting hole (not shown) formed in the light source unit 4 fitted into the recess 2 from the back surface side of the light guide plate as described above, and has an octagonal shape. 8 are formed in the vicinity of the corners. The position of the light source unit mounting through hole 11 of the light guide plate thus formed and the position of the fixing mounting hole of the light source unit 4 are matched, and the light source unit 4 is fixed by tightening the screws 5 from the back side of the light guide plate. is doing. Reference numeral 8 denotes a power cable. A male waterproof connector is attached to one cable of the two power cables led out from the light source unit, and a female waterproof connector is attached to the other cable. By connecting the power cable 8 and the waterproof connector, it is possible to connect up to 100 surface light emitting devices in a tandem manner, and the first stage device of a plurality of connected surface light emitting devices is connected to a commercial AC 100 volt power supply. The terminals are connected to each other, and the supplied power can be supplied all at once to all the surface emitting devices connected in series.

  Next, the detailed structure of the light source unit 4 will be described with reference to FIGS. FIG. 2 is a diagram illustrating the light source unit 4 in plan view, and FIG. 3 is a diagram illustrating a cross section of the light source unit 4 attached to the light guide plate 1. Reference numeral 12 denotes a rigid printed circuit board formed in a rectangular plate shape, and an octagonal light emitter is configured by combining two types of printed circuit boards having different lengths. This octagon corresponds to the shape of the recess 2 formed in the central portion of the light guide plate 1, and a print having a short length is located at a position parallel to each side constituting the outer peripheral edge of the light guide plate. A substrate is disposed, and a printed circuit board having a long length is disposed at a position perpendicular to the diagonal line of the light guide plate. Two LEDs 13 as light emitting elements are arranged on the short-sized printed circuit board, and three LEDs 13 are arranged on the long-sized printed circuit board. Light is emitted from the end face 1a toward the inside of the light guide plate. By comprising in this way, according to the distance of LED13 of a light source unit, and the outer-periphery edge part of the light-guide plate 1, a short distance (direction which puts the printed circuit board 12 in parallel with the side of a light-guide plate), and distance The amount of light emitted in the long direction (the direction in which the printed circuit board 12 is placed perpendicular to the diagonal line of the light guide plate) is adjusted to prevent the occurrence of uneven brightness during light emission. Reference numeral 14 denotes a front-direction LED that irradiates light in a direction perpendicular to the LED 13, and is mounted on an inner side of an octagon formed by combining the printed circuit boards 12, with a milk semi-resin plate 3 in the front direction of the light guide plate. Irradiate light. In addition to this LED 13, a light emitting power supply circuit is mounted on the inner side of the octagon, and only the front direction LED 14 is exposed in the front direction of the light guide plate, except for the front direction LED 14. (A reflector plate is not shown in FIG. 2 for easy understanding of the configuration). By attaching this reflector plate, external light incident on the octagonal inner space through the milk half resin plate 3 again when exposed to strong external light or sunlight from above the front of the light guide plate Reflected toward the outside. As a result, when there is no reflector plate, a part of the external light received from the outside is absorbed into the octagonal inner space and is seen as a dark part from the front of the light guide plate, whereas when receiving strong external light This also prevents the appearance of dim shadows on the surface of the light guide plate.

  Reference numeral 15 denotes a casing, which includes a resin-molded shallow cylindrical housing portion, and a portion remaining in a state in which the LED on the printed circuit board combined in an octagon is protruded upward is housed in the casing. Reference numeral 16 denotes an annular seal packing, which is provided at a contact portion between the casing 15 and the back surface of the light guide plate 1, and the eight fixing attachment holes 17 provided in the casing 15 are connected to the light source unit attachment through holes 11 of the light guide plate 1. By tightening the screw 5 in the state of being aligned with the lens, waterproofness is easily ensured simultaneously with the mounting.

  Next, the positional relationship between the installation through hole 10 and the light source unit mounting through hole 11 provided in the light guide plate will be described with reference to FIG. FIG. 4 shows a state in which the light guide plate 1 and the light source unit 4 are combined together, and the light source unit 4 is fitted and mounted in the recess 2. As described above, the recess 2 and the light source unit 4 both have an octagonal shape, and the installation through-hole 10 and the light source unit are arranged on an extension line connecting the octagonal center portion 20 and the eight corner portions. The mounting through hole 11 is provided, and the installation through hole 10 and the light source unit mounting through hole 11 are arranged so as to be arranged radially from the central portion 20 of the light source unit 4 toward the outer peripheral edge of the light guide plate. By arranging in this way, it is possible to prevent the light emitted from the LED mounted on the octagonal straight portion from directly hitting the installation through hole 10 and the light source unit mounting through hole 11 respectively. It is possible to prevent the through-holes from blocking the light that arrives and form a shadow on the light-emitting surface of the light guide plate. The fan-shaped range shown in FIG. 4 shows the light irradiation range as an image based on the half-value angle data of the LED, and the light irradiated from the LED of the light source unit as shown in FIG. Direct contact with the light source unit mounting through-hole 11 is avoided. And even if the light emitted from the LED of the light source unit hits the installation through hole located near the outermost periphery of the light guide plate, it prevents the shadow from being generated by receiving the light traveling from another direction. In addition, the light guide plate can be provided with uniform light emission without unevenness of brightness, although the light guide plate is provided with an installation through-hole that greatly improves the efficiency of the apparatus construction work.

  The present invention is configured as described above, but various implementations are possible without being limited to the above-described embodiments. For example, the polygon formed by the rigid printed circuit board of the light source unit 4 may be a polygon other than an octagon. Further, the number of through holes for installation is 12 in this embodiment, but is not limited to this.

  As an application example of the surface light-emitting device of the present invention, it can be applied to various internally illuminated signs (lighting signs, advertising panels, etc.), backlights of liquid crystal display devices, general lighting devices, and the like.

DESCRIPTION OF SYMBOLS 1 Light guide plate 1a End surface 2 of the light guide plate facing a recessed part 2 Recessed part 3 Milk half resin board 4 Light source unit 5 Screw 6 Light reflecting sheet 7 Reflecting dot 8 Power supply cable 10 Installation through-hole 11 Light source unit installation through-hole 12 Rigid printed circuit board 13 LED
14 Front LED
15 Casing 16 Annular seal packing 17 Fixing hole (for light source unit)

Claims (3)

In a surface light emitting device that emits light in a planar shape by introducing light emitted from a light emitting element into the light guide plate from the end face of the light guide plate, and emitting the introduced light from the surface of the light guide plate,
A recess formed in the center of the light guide plate;
A light source unit comprising a plurality of light emitting elements housed in the recess,
The light source unit includes a plurality of rigid printed boards on which light emitting elements are mounted arranged in a polygon, and the mounting surface of the printed board constituting the polygonal linear portion is parallel to the side of the light guide plate. The light guide plate is fixed to the light guide plate in a positional relationship perpendicular to the diagonal line of the light guide plate, and the light emitted from the mounted light emitting element is introduced into the light guide plate from the end face of the light guide plate facing the recess. Surface emitting device.   The light guide plate is provided with an installation through hole penetrating from the front surface of the light guide plate to the rear surface side in order to fix and install the light guide plate, and the position where the installation through hole is formed is at the center of the light guide plate. 2. The surface light emitting device according to claim 1, wherein the surface light emitting device is on a surface of a light guide plate on an extension line connecting a polygonal central portion and a polygonal corner portion of the light source unit to be fixed.   The light guide plate is provided with a light source unit mounting through-hole penetrating from the front surface to the back surface of the light guide plate in order to fix the light source unit to the light guide plate, and the light source unit mounting through-hole is formed. 2. The surface light emission according to claim 1, wherein the surface light emission is on a surface of the light guide plate on an extension line connecting a polygonal central portion and a polygonal corner portion of the light source unit fixed to the center of the light guide plate. apparatus.

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