JP2013229260A - Light-emitting device, information display device and lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting device, an information display device and a lighting device capable of saving power by suppressing light leak from side end surfaces of a light guide plate.SOLUTION: A light-emitting device 10 includes a light guide plate 20 having an approximately rectangular planar shape where light incident from at least one end surface 20a of a pair of opposed short sides in a perpendicular direction of the side end surface 20a emits from an emitting surface, and a plurality of LEDs 12 letting light incident into the light guide plate 20. A plurality of concavo-convex shaped streaky bodies T are formed on the light-emitting surface 20b of the light guide plate 20 along a direction perpendicular to the light-incident end surface 20a.

Description

  The present invention relates to a light emitting device, an information display device, and a lighting device including a side edge (also referred to as a side light) type light guide plate that emits light from a light emitting diode in a planar shape by a light guide plate. The present invention relates to power saving by suppressing light leakage from the side end face of the light guide plate.

  Conventionally, in information display devices such as advertising towers and guide lights, since it is necessary to keep them on for a long time, it is common to illuminate a fluorescent lamp inside a panel for displaying information.

  As such an information display device, for example, a fluorescent lamp lighting signboard device 100 disclosed in Patent Document 1 is a rectangular parallelepiped having a hollow inside attached to a wall surface 101 of a building using a column 102 as shown in FIG. It has become. The outer surface of the fluorescent lamp illumination signboard device 100 is formed by attaching a colored face plate sheet (not shown) on the translucent display board 110, and the fluorescent lamp 111 is accommodated therein. And by lighting the fluorescent lamp 111 at night, the information of the colored face plate sheet is displayed brightly.

  Further, for example, in the guide light device 200 disclosed in Patent Document 2, as shown in FIG. 14A, a resin-made instrument body 201 is sandwiched between a front display panel device 210 and a rear display panel device 220. It consists of things. The front display panel device 210 and the rear display panel device 220 have the same configuration, and include light sources 211 and 221 on the upper side and display units 212 and 222 on the lower side. The light sources 211 and 221 are made of fluorescent lamps, and the display parts 212 and 222 have a guidance display part 213 made of a sticker or the like.

  Here, as shown in FIG. 14B, the display unit 212 of the guide lamp device 200 includes a light guide plate 214, and an emission surface of the light guide plate 214 has a light source 211 made of a fluorescent lamp. A plurality of triangular grooves 214a... Along the direction perpendicular to the end face on which light is incident are formed. The configuration of the display unit 222 is the same.

  As a result, the directivity of light in the emission direction can be improved in the display units 212 and 222 including the side edge (also referred to as side light) type light guide plate.

  Further, for example, as shown in FIG. 15, the illumination device 300 disclosed in Patent Document 3 includes LEDs (Light Emitting Diodes) 301... On both end surfaces 311 and 311 on the short side of a rectangular light guide plate 310. It consists of things arranged. With this configuration, the lighting device 300 is provided with a side edge (also referred to as a side light) type light guide plate using LEDs 301..., So that the lighting device 300 can be thinned.

JP 2007-011044 A (published on January 18, 2007) JP 2000-149634 A (published May 30, 2000) JP 2010-267610 A (published on November 25, 2010)

  However, the fluorescent lamp illumination signboard device 100 disclosed in the above-mentioned conventional patent document 1 and the guide lamp device 200 disclosed in patent document 2 use a fluorescent lamp as a light source, and cannot be reduced in thickness. Has a problem.

  Moreover, in the illuminating device 300 disclosed by patent document 3, although it can evaluate in the point which implement | achieves thickness reduction of the illuminating device 300 by using LED301 as a light source, the light leakage from the both ends of the rectangular light-guide plate 310 is carried out. There is a problem that it is difficult to reduce power consumption for long lighting.

  The present invention has been made in view of the above-described conventional problems, and an object thereof is to suppress light leakage from the side end face of the light guide plate and to save power, an information display device, and an information display device. The object is to provide a lighting device.

  In order to solve the above-described problem, the light emitting device of the present invention has a rectangular planar shape, and emits light incident in a direction perpendicular to the end surface from at least one of a pair of opposed short side end surfaces from the output surface. In a light emitting device including a light guide plate that emits light and a plurality of light emitting diodes that allow light to enter the light guide plate, the light exit surface of the light guide plate includes a plurality of light sources along a direction perpendicular to an end surface on which the light enters. It is characterized by the formation of streak-like uneven shapes.

  According to the above invention, the light-emitting device has a rectangular planar shape, and guides light that is incident in a direction perpendicular to the end surface from at least one of a pair of opposing short-side end surfaces from the output surface. And a plurality of light emitting diodes that allow light to enter the light guide plate.

  Thereby, since the light emitting diode is arrange | positioned at the short side of the light-guide plate, the length which arrange | positions a light emitting diode becomes short. For this reason, the mounting operation of the light emitting diode can be simplified, and members such as wiring for supplying power to the light emitting diode can be reduced. As a result, the manufacturing cost can be reduced.

  In addition, since no light emitting diode is arranged in the longitudinal direction of the light guide plate, the frame size along the longitudinal direction of the light guide plate can be reduced. As a result, the light guide plate can be slimmed, and the design can be improved. Further, even when a plurality of light guide plates are arranged side by side, the light emitting diode does not get in the way. Therefore, application to various types of products is possible.

  On the other hand, in a light emitting device using this type of light guide plate, when the light guided through the light guide plate has a light spread in a direction parallel to the end surface on which the light is incident, the longer side of the light guide plate There is a problem that light leakage from the light increases.

  Therefore, in the present invention, a plurality of streaky uneven shapes along the direction perpendicular to the end surface on which light is incident are formed on the exit surface of the light guide plate. As a result, the straightness of the light guided inside the light guide plate is enhanced by the plurality of streaky irregularities, and the spread of the light in the direction parallel to the end surface on which the light is incident can be suppressed. Light leakage from the side can be reduced.

  Therefore, it is possible to provide a light-emitting device that can suppress light leakage from the side end face of the light guide plate and save power.

  In the light emitting device of the present invention, it is preferable that the length of the long side of the light guide plate is at least twice the length of the short side.

  Thereby, when the length of the long side in the light guide plate is twice or more than the length of the short side, the light spread in a direction parallel to the end surface on which the light is incident occurs in a long range, The energy loss of light increases. For this reason, especially in such a case, the effect of suppressing power leakage from the side end face of the light guide plate and saving power is great.

  In the light-emitting device of the present invention, it is preferable that the plurality of streaky uneven shapes on the light exit surface of the light guide plate have a cross-sectional shape of an arc shape or an arc shape.

  Thereby, light straightness can be improved rather than the uneven | corrugated shape comprised by the polygon like a triangular shape.

  In the light emitting device of the present invention, the combination of the light guide plate and a plurality of light emitting diodes provided on at least one end surface on the short side of the light guide plate is such that the long sides of the adjacent light guide plates face each other. It can be assumed that a plurality of sets are arranged.

  Thereby, a large light-emitting device can be realized.

  Further, in the conventional light guide plate having no streak-like uneven shape on the exit surface, light straightness is low, and thus light leakage occurs from the long side. For this reason, bright lines are generated at the joints between the adjacent light guide plates, and the joints are conspicuous, so that the quality of the lighting device is lowered.

  On the other hand, in the light emitting device of the present invention, there is no light emitting diode on the long side of the light guide plate, so that the joining of the light guide plates is not hindered, and a streaky uneven shape is present on the exit surface. As a result, light straightness is improved. As a result, the joint between the light guide plates does not stand out.

  In order to solve the above problems, an information display device of the present invention is an information display device including the above-described light-emitting device, and an information display unit is provided on a light emission surface of the light-emitting device. It is a feature. The information display unit is a member for displaying a stationary design such as a character or a picture. Specifically, it is a member that displays a design such as an advertisement, a signboard, a sign, a guide map, or a poster, and includes a drawing or the like.

  According to said invention, the information display apparatus consists of what used the light-emitting device of this invention as a backlight for irradiating an information display part from a back surface. As a result, the information display device of the present invention can be used as an advertisement panel, a signboard, a sign panel, a guide panel, or a poster panel.

  In order to solve the above-described problems, an illumination device of the present invention includes the light-emitting device described above.

  According to said invention, it becomes possible to utilize the light-emitting device of this invention as an illuminating device for illuminating indoors or the outdoors.

  As described above, in the light emitting device of the present invention, a plurality of streaky irregularities along the direction perpendicular to the end surface on which light is incident are formed on the exit surface of the light guide plate.

  As described above, the information display device of the present invention is an information display device including the above-described light-emitting device, and an information display unit is provided on the light emission surface of the light-emitting device.

  As described above, the lighting device of the present invention includes the light emitting device described above.

  Therefore, it is possible to provide a light emitting device, an information display device, and an illumination device that can suppress light leakage from the side end face of the light guide plate and save power.

1 shows an embodiment of a light emitting device and an information display device according to the present invention, and is a cross-sectional view showing an overall configuration of an information display device including the light emitting device of the present embodiment. It is a disassembled perspective view which shows the structure of the information display apparatus provided with the said light-emitting device. It is principal part sectional drawing which shows the structure of the said information display apparatus. It is a principal part perspective view which fractures | ruptures and shows the structure of the said light-emitting device. It is sectional drawing which shows the emitted light from the uneven | corrugated shaped body formed in the output surface of the light-guide plate in the said light-emitting device. (A)-(d) is sectional drawing which shows the various shapes of the uneven | corrugated shaped body formed in the output surface of the light-guide plate in the said light source module. (A) is a top view which shows the spread of the propagation light in the light-guide plate which consists of flat plates, (b) is sectional drawing which shows the spread of the propagation light in the light-guide plate which consists of flat plates. (A) is a top view which shows the spread of the propagation light in the light-guide plate which has an uneven | corrugated shaped body, (b) is sectional drawing which shows the spread of the propagation light in the light-guide plate which has an uneven | corrugated shaped body. (A) is a side view which shows the side shape of the X direction in the light guide plate with a small uneven | corrugated shaped body, (b) is the side surface which shows the side shape of the X direction in the light guide plate with a small uneven | corrugated shaped body. FIG. (A) is sectional drawing which shows schematic structure of the light-guide plate (structure I) which formed the uneven | corrugated shaped body on the conditions that uneven | corrugated height h / pitch P is 0.4 with respect to the thickness H of a light-guide plate, b) is a guide in which a concavo-convex shaped body is formed under the condition that the concavo-convex height h / pitch P is 0.4 with respect to the thickness H of the light guide plate, where the pitch P is P / 2 and the concavo-convex height h is h / 2. It is sectional drawing which shows schematic structure of an optical plate (structure II), (c) is the ratio of uneven | corrugated height h / pitch P, and even if the pitch P is halved, the effect of optical confinement does not change, It is a graph which shows that. (A) is a top view which shows the structure of the light-guide plate which does not have an uneven | corrugated shaped body of short direction width W and long direction length L, (b) is unevenness of short direction width W and long direction length L. It is a top view which shows the structure of the light-guide plate which has a shape body, (c) is a figure which shows the ratio of the light leakage from the light-guide plate side surface when changing the aspect ratio and aspect ratio of a light-guide plate. It is a top view which shows the light-emitting device which arrange | positioned the some light guide plate side by side. It is a perspective view which shows the structure of the conventional light-emitting device. (A) is a disassembled perspective view which shows the structure of the other conventional light-emitting device, (b) is a perspective view which shows the structure of the light-guide plate with which the said light-emitting device was equipped. It is a top view which shows the structure of other conventional light-emitting devices.

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

(Configuration of information display device)
Initially, the whole structure of the information display apparatus provided with the light-emitting device of this Embodiment is demonstrated based on FIGS. FIG. 1 is a cross-sectional view showing an overall configuration of an information display device including the light emitting device of the present embodiment. FIG. 2 is an exploded perspective view illustrating a configuration of an information display device including the light emitting device according to the present embodiment. FIG. 3 is a cross-sectional view of the main part showing the configuration of the information display device.

  As shown in FIGS. 1 and 2, the information display device 1 including the light emitting device 10 according to the present embodiment has a chassis 2, a light emitting device 10, an information display unit 3, a protective sheet 4, and a cover 5 in order from the rear. The light emitting device 10 includes a reflection sheet 11, an LED (Light Emitting Diode) 12, an LED substrate 13, a reflector 14, a light guide plate 20, and an optical sheet 17 such as a diffusion sheet. Note that the optical sheet 17 and the protective sheet 4 may not be present in the present invention. The configuration of the optical sheet 17 is an example, and for example, a so-called microlens sheet may be used.

  In the present embodiment, the light guide plate 20 has a rectangular planar shape. However, the light guide plate 20 does not necessarily have a rectangular planar shape, and the rectangle may have some unevenness. Moreover, a parallelogram may be sufficient. However, a pair of opposing sides, such as a parallelogram, is longer than the other pair of opposing sides. Furthermore, in the light guide plate 20 of the present embodiment, it is preferable that the dimension in the longitudinal direction is twice or more than the dimension in the lateral direction.

  Here, the longitudinal direction of the light guide plate 20 is the X direction, the normal direction of the light guide plate 20 is the Z direction, and the direction perpendicular to the X direction and the Z direction is the short direction of the light guide plate 20. The direction.

  As shown in FIG. 3, an LED 12, a LED substrate 13, and a reflector are disposed on either side of the pair of end surfaces 20a and 20a on the short side of the light guide plate 20 of the light emitting device 10. A light source unit 15 having 14 is provided. In addition, a plurality of optical path conversion units 16 for taking out light guided inside the light guide plate 20 is provided on the lower surface 20c as a surface opposite to the light exit surface 20b of the light guide plate 20. ing. The optical path conversion unit 16 is made of, for example, a scatterer formed by printing ink containing a microprism, a microlens, or a diffusing material.

  Thus, the light from the LED 12 is incident on one end face 20a of the light guide plate 20, and the light is guided while being totally reflected inside the light guide plate 20, and a plurality of optical paths provided on the lower surface 20c of the light guide plate 20 The total reflection condition is broken by the conversion unit 16, and the information display unit 3 is irradiated with light from the emission surface 20 b of the light guide plate 20 through the optical sheet 17.

  Therefore, the light emitting device 10 according to the present embodiment employs a side edge (also referred to as side light) method. Note that light is emitted from the light guide plate 20 from surfaces other than the emission surface 20b. However, since the reflection sheet 11 is disposed on a surface other than the light exit surface 20b of the light guide plate 20 and the surface on which the LEDs 12 are disposed, and is incident on the light guide plate 20 again, most of the light is emitted from the light exit surface 20b. Emitted. Here, the light source unit 15 is provided on both the pair of end surfaces 20 a along the short direction of the light guide plate 20. However, the present invention is not necessarily limited thereto, and the light source unit 15 may be provided on either one of the pair of end surfaces 20a in the short direction of the light guide plate 20. In other words, in the present invention, the light source unit 15 only needs to be provided on at least one of the pair of end faces 20a and 20a in the short direction of the light guide plate 20.

  The information display unit 3 is composed of a member for displaying a stationary design such as a character or a picture. Specifically, for example, a member that displays a design such as an advertisement, a signboard, a sign, a guide map, or a poster, including a drawing by directly applying to the light emitting device 10. The information display unit 3 is made of paper, transparent resin, translucent resin, opaque resin, metal or the like. By irradiating light from the back surface with the light emitted from the optical sheet 17, the information display unit 3 can be displayed brightly regardless of day or night.

  Therefore, the information display device 1 according to the present embodiment can be applied as, for example, an advertisement panel, a signboard, a sign panel, a guide panel, or a poster panel by displaying on the information display unit 3.

  The protective sheet 4 is made of hard plastic or the like. In addition, when the information display part 3 itself consists of a hard coat layer, the protective sheet 4 may not be provided.

  The cover 5 covers the edges of the information display unit 3 and the protective sheet 4. The cover 5 may be integrated with the chassis 2.

(Configuration of light emitting device)
As shown in FIG. 4, the light guide plate 20 in the light emitting device 10 of the present embodiment has the shape of the emission surface 20 b along the direction perpendicular to the end surface 20 a on which the light of the plurality of LEDs 12 in the light source unit 15 is incident. A plurality of streak-like uneven bodies T are formed. Specifically, the plurality of streak-like uneven bodies T are formed by arranging a plurality of curved surface structures formed of curved surfaces having a cross-sectional arc shape or a cross-sectional arc shape. This uneven | corrugated shaped body T ... is formed as a streak pattern along the longitudinal direction of the light-guide plate 20, for example. That is, the light guide plate 20 has a plurality of concave and convex shapes T formed of curved surfaces having ridge lines parallel to the longitudinal direction on the light emission surface 20b. The concavo-convex shaped body T is a structure formed on the emission surface 20 b of the light guide plate 20, and is not provided on the light guide plate 20 as a separate member from the light guide plate 20.

  In the light guide plate 20 including the emission surface 20b having the plurality of streaky uneven shapes T, the light scattered by the optical path changing unit 16 is caused by the uneven shape T as shown in FIG. The emitted light is refracted toward the center of the concavo-convex shaped body T. For this reason, the uneven shape body T can suppress the spread of light to the side, and the straightness of the emitted light can be improved. That is, the light beam emitted from the light guide plate 20 is collected. As a result, the information display unit 3 has an advantage that the average luminance of the entire screen can be improved.

  By the way, in the case of a conventional light guide plate having an emission surface, a prism sheet is provided as one of the optical sheets 17 to ensure a function of increasing the straightness of the emitted light. However, in the light emitting device 10 according to the present embodiment, by providing the light guide plate 20 with a plurality of concavo-convex shaped bodies T, the average luminance of the entire screen in the information display unit 3 can be improved as compared with the case where a prism sheet is provided. Is possible. For this reason, in the light-emitting device 10 of this Embodiment, the prism sheet is not provided. However, the present invention is not necessarily limited to this, and a prism sheet can be provided.

  In the present embodiment, it is preferable to provide an optical sheet 17 such as a diffusion sheet. This is because, when the concavo-convex shaped body T is formed on the exit surface 20b of the light guide plate 20, the visibility of the pattern of the optical path changing unit 16 on the lower surface 20c of the light guide plate 20 can be reduced.

Here, in order to improve the straightness of such emitted light, as shown in FIG. 5, the unevenness height in the direction perpendicular to the exit surface 20 b of the uneven shape body T of the light guide plate 20 is set to h, When the pitch between the shaped bodies T is P, the aspect ratio (unevenness height h / pitch P) is
0.1 <h / P <0.5
It is preferable to have a relationship satisfying By setting the aspect ratio (height of unevenness h / pitch P) in the range of 0.1 to 0.5, the straightness of light can be improved, and fluctuations in straightness with respect to unevenness of the uneven shape can be improved. This is because the characteristic variation of the light emitting device 10 can be suppressed. The aspect ratio (uneven height h / pitch P) will be described in detail later.

  The specific shape of the concavo-convex shaped body T for providing such an effect is preferably a cylinder shape such as a cross-sectional arc shape or an arc shape as shown in FIG. In this case, the light can be efficiently extracted at various incident angles from the vertical light A rising vertically to the light C guided at a shallow angle, and the light can be emitted from the emission surface. Further, when the thickness of the light guide plate 20 is the same, the shape shown in FIG. 6A can easily ensure a larger cross-sectional area than the prism shape described later. As a result, in the configuration in which the uneven surface T having a semicircular cross section is formed on the light exit surface 20b of the light guide plate 20, the light coupling efficiency on the light incident surface from the LED 12 is high, and light leakage hardly occurs. Such a shape can be formed by extruding the light guide plate 20.

  Here, the structure of the concavo-convex shaped body T is not necessarily the cylinder shape such as the cross-sectional arc shape or the arc shape shown in FIG. 6A, but the shape shown in FIGS. 6B, 6C, and 6D. Is also possible.

  The uneven shape body T shown in FIG. 6B is formed by a prism having an apex angle of 90 ° formed on the emission surface 20 b of the light guide plate 20. In this case, the vertical light A becomes return light without breaking the total reflection condition. Further, the light C guided at a shallow angle is once emitted from the emission surface because the total reflection condition is broken. However, the light again enters the adjacent prism and returns to the light guide plate 20.

  The concave-convex shaped body T shown in FIG. 6C is formed by forming a prism with an apex angle of 5 ° on the exit surface of the light guide plate 20. In this case, the vertical light A and the light C guided at a shallow angle are both emitted from the emission surface because the total reflection conditions are broken. However, the probability that these lights will re-enter the adjacent prism increases.

  Therefore, as shown in FIGS. 6B and 6C, when a prism is formed on the light emission surface 20b of the light guide plate 20, the efficiency of emitting light from the light guide plate 20 to confine light in the light guide plate 20 is reduced. May end up.

  6D has a structure having a concave cylinder surface that is recessed with respect to the emission surface 20b of the light guide plate 20. In this case, the vertical light A does not become return light due to total reflection. Therefore, the concavo-convex shape body T shown in FIG. 6D can emit light from the light guide plate 20 more efficiently than the configuration shown in FIGS. 6B and 6C. .

(Specific shape to suppress light leakage from the side of the light guide plate)
Specifics of the concavo-convex shape body T for suppressing light leakage from the side surface of the light guide plate 20 in the light emitting device 10 using the light guide plate 20 having the emission surface 20b having the plurality of streaky concavo-convex shape bodies T described above. In describing the target shape, first, the effect of suppressing light leakage from the side surface of the light guide plate will be described in detail below with reference to FIGS. 7 (a) and 7 (b) and FIGS. 8 (a) and 8 (b). 7A is a plan view showing the spread of the propagation light in the light guide plate made of a flat plate, and FIG. 7B is a cross-sectional view showing the spread of the propagation light in the light guide plate made of a flat plate. FIG. 8A is a plan view showing the spread of propagation light in the light guide plate having an uneven shape body, and FIG. 8B is a cross-sectional view showing the spread of propagation light in the light guide plate having an uneven shape body. is there.

  That is, in the conventional light guide plate having a flat emission surface, as shown in FIG. 7A, light from the LED incident from the end surface of the light guide plate propagates radially inside the light guide plate. . As a result, as shown in FIG. 7B, light leakage from the side surface of the light guide plate increases.

  On the other hand, when a light guide plate 20 having an emission surface 20b having a plurality of streaky uneven bodies T ... is used as in the light emitting device 10 of the present embodiment, as shown in FIG. In addition, since the light from the LED 12 of the light source unit 15 incident from the end surface of the light guide plate 20 has high straightness, the light from the side surface of the light guide plate 20 from the side surface of the light guide plate 20 as shown in FIG. Light leakage is reduced. That is, since the light rays are confined by the concavo-convex shape body T, the light rays reaching the side surface are reduced.

  Therefore, in order to enhance the effect of suppressing light leakage from the side surface of the light guide plate 20, the shape of the concavo-convex shaped body T is greatly affected. Therefore, a specific shape of the concavo-convex shaped body T will be described below.

  First, the unevenness height h in the uneven shape body T will be described. Initially, the uneven | corrugated height h when the uneven | corrugated pitch P in the uneven | corrugated shaped body T is made constant is demonstrated based on Fig.9 (a) (b). FIG. 9A shows a side shape of the light guide plate 20 in the X direction, and is a side view showing a case where the uneven height h of the uneven shape body T is small, and FIG. It is a side view which shows the side surface shape of the X direction in FIG., Comprising: The uneven | corrugated height T of the uneven | corrugated shaped body T is large. 9A and 9B, the pitch P of the uneven body T and the thickness H of the light guide plate 20 are the same.

  In the light emitting device 10 according to the present embodiment, the light from the LED 12 is incident on the short-side end surface 20 a of the light guide plate 20. Accordingly, when the uneven pitch P of the uneven shape body T is constant, the unevenness of the uneven shape body T in the light incident surface shape (side surface shape in the X direction in the light guide plate 20) as shown in FIG. 9B. When the height h is large, the incident area is small, so that light leaks from the gap (the hatched portion shown in FIG. 9B), and the light coupling efficiency of the LED 12 decreases. On the other hand, as shown in FIG. 9A, when the uneven height h of the uneven shape body T is small in the light incident surface shape (side surface shape in the X direction of the light guide plate 20), the incident area becomes large and the gap Light leakage can be reduced, and the optical coupling efficiency can be improved.

  Therefore, the light coupling efficiency and the light leakage at the light incident surface decrease as the unevenness height h of the uneven shape body T increases as the unevenness pitch P of the uneven shape body T is the same. Approximately, when the uneven height h of the uneven shaped body T is doubled, the amount of light leakage is doubled and the loss of optical coupling efficiency is also doubled.

  As a result, it can be said that the shape of the concavo-convex shaped body T on the exit surface 20b of the light guide plate 20 is preferably an arc shape in cross section or an arc shape in which the arc shape is flattened.

  Specifically, in consideration of light coupling efficiency and light leakage at the end face 20 a on which the light of the LED 12 is incident, the uneven height h of the uneven shape body T is preferably 10% or less of the thickness H of the light guide plate 20. . When the uneven height h of the uneven shape body T exceeds 10% of the thickness H of the light guide plate 20, the light coupling efficiency of the LED 12 is greatly reduced (light leakage is about 5% of incident light). Therefore, it is not preferable.

  In addition, when the thickness H of the light guide plate 20 is reduced, the uneven shape body T may not be manufactured unless the uneven height h is 5% or more of the thickness H of the light guide plate 20. That is, when the light guide plate 20 becomes thin, it is difficult to produce the concavo-convex shape body T when the range of the concavo-convex height h of the concavo-convex shape body T is 5% or less of the thickness H. Therefore, in consideration of realistic dimensions of the uneven shape body T, the uneven height h of the uneven shape body T is preferably 5% or more and 10% or less of the thickness H of the light guide plate 20. As specific dimensions, for example, the thickness H of the light guide plate 20 is 4.2 mm, and the uneven height h of the uneven shape body T is 0.3 mm.

  Next, the unevenness height h when the unevenness pitch P in the uneven shape body T is changed will be described based on FIGS. 10 (a), 10 (b), and 10 (c). FIG. 10A shows the light guide plate 20 (Configuration I) in which the concavo-convex shape body T is formed on the condition that the aspect ratio (concave height h / pitch P) is 0.4 with respect to the thickness H of the light guide plate 20. FIG. 10B is a cross-sectional view showing a schematic configuration, and FIG. 10B shows a light guide plate 20 (with a pitch of P / 2 and a height of unevenness of h / 2 in the uneven shape body T of FIG. 10A. It is sectional drawing which shows schematic structure of the structure II).

  As described above, the optical coupling efficiency at the light incident surface decreases as the uneven height h of the uneven shape body T increases with respect to the thickness H of the light guide plate 20. Therefore, it is preferable to reduce the ratio of the uneven height h of the uneven shape body T to the thickness H of the light guide plate 20. For this reason, as shown in FIG. 10B, it is conceivable that the uneven height h is set to h / 2 in the uneven body T of FIG. In this case, in order to maintain the condition of the aspect ratio (uneven height h / pitch P) 0.4 with respect to the thickness H of the light guide plate 20, the pitch of the uneven shape body T needs to be P / 2. There is.

  Here, in this case, as shown in FIG. 10 (c), when the aspect ratio (uneven height h / pitch P) is the same, the effect of light confinement does not change even if the pitch P is halved. . That is, it can be seen that there is no change in light straightness between Configuration I and Configuration II.

  Therefore, it is possible to secure the cross-sectional area of the light guide plate 20 while maintaining the light straightness by reducing the pitch P of the unevenness of the uneven shape body T without changing the shape of the uneven shape body T. . Therefore, by using the configuration II in which the pitch P is smaller than the configuration I, the optical coupling loss can be halved. Further, by making the pitch P fine, it is possible to make it difficult to visually recognize the concavo-convex shaped body T extending in the longitudinal direction.

  10A, 10 </ b> B, and 10 </ b> C, as the configuration I, the pitch P of the concavo-convex shape body T = 0.4 mm, the concavo-convex height h of the concavo-convex shape body T = 0.16 mm, and the thickness of the light guide plate 20. A light guide plate 20 having a height of H = 4.2 mm is used. Further, as the configuration II, a light guide plate 20 having a pitch P of the concavo-convex shape body T = 0.2 mm, a concavo-convex height h = 0.08 mm of the concavo-convex shape body T, and a thickness H = 4.2 mm of the light guide plate 20 is used. Yes. In the configuration I and the configuration II, the semicircular arc shape in the concavo-convex shape body T is similarly halved.

  Here, according to the above description, when the shape of the concavo-convex shape body T is a convex cylinder shape, there is a light straightness effect. Therefore, the shape of the concavo-convex shape body T is sufficient if the cross-sectional shape perpendicular to the longitudinal direction (X direction) includes an arc on the emission surface 20b of the light guide plate 20, even if a part of the cross-sectional shape is a straight line. Good. That is, the lower surface 20c of the light guide plate 20 may be a straight line. Such a shape can be formed by extruding the light guide plate 20, and the light guide plate 20 can also be formed by press working or the like.

  Next, the relationship between the lateral width W and the longitudinal length L of the light guide plate 20 and the light leakage from the side surface of the light guide plate 20 will be described based on FIGS. 11 (a), 11 (b), and 11 (c). . FIG. 11A is a plan view showing a configuration of a light guide plate that does not have a concavo-convex shape body having a lateral width W and a longitudinal length L, and FIG. 11B is a lateral width W and a longitudinal length. FIG. 11C is a plan view showing a configuration of a light guide plate having a concavo-convex shape body having a thickness L, and FIG. 11C is a diagram showing a guide when the aspect ratio and the aspect ratio (uneven height h / pitch P) of the light guide plate are changed. It is a figure which shows the ratio of the light leakage from a light-plate side surface.

  As shown in FIG. 11 (c), the width W and the length L in the short direction of the light guide plate 20 are 100: 500, 100: 1000, 100: 2000, or 100: 3000, When the aspect ratio (roughness height h / pitch P), which is the ratio of the thickness H of the light guide plate 20 to the pitch P of the concavo-convex shape body T, increases, the light from the side surface of the light guide plate 20 with respect to the flat light guide plate It can be seen that the rate of leakage is reduced. For example, when the lateral width W = 100 mm and the longitudinal length L = 1000 mm, the leakage light from the side surface of the light guide plate 20 has an aspect ratio (uneven height h) when the uneven body T exists. / Pitch P) is set to 0.4, it can be seen that 25% of the flat plate can be reduced.

  However, as shown in FIG. 11C, the side surface of the light guide plate 20 is increased by increasing the length L in the longitudinal direction of the light guide plate 20, that is, by increasing the length L in the longitudinal direction / the width W in the short direction. It can be seen that the light leakage from the light tends to increase.

  Although not shown in FIG. 11 (c), in the experiment, when the longitudinal length L of the light guide plate 20 is more than twice the lateral width W, the light is larger than that of the flat light guide plate. It has been found that there is a leakage prevention effect.

  Here, for light leakage from the side surface of the light guide plate 20, for example, it is possible to prevent light leakage by attaching a reflective tape to the side surface of the light guide plate 20. However, in this case, energy loss is reduced by suppressing light leaked from the side surface, but this is not preferable because the change in light chromaticity due to the reflective tape is increased.

  By the way, in the above description, the configuration in which the light guide plate 20 and the LED 12 are provided on the end surface 20a has been described, but the light emitting device 10 of the present embodiment is not limited to this configuration.

  For example, as shown in FIG. 12, a plurality of combinations of the light guide plate 20 and the LEDs 12 on the end surface 20a may be arranged such that the long sides of the adjacent light guide plates face each other. . Thereby, since the large sized light-emitting device 10 is realizable, it can be used for a large-scale advertisement panel. For example, it can be used for a ball playground.

  As described above, the light emitting device 10 according to the present embodiment has a rectangular planar shape, and emits light that is incident in a direction perpendicular to the end surface 20a from at least one of the pair of opposed end surfaces 20a on the short side. The light guide plate 20 that exits from the light guide 20b and a plurality of LEDs 12 that allow light to enter the light guide plate 20 are provided. A plurality of streak-like uneven bodies T are formed on the exit surface 20b of the light guide plate 20 along a direction perpendicular to the end surface 20a on which light is incident.

  According to said structure, since LED12 is arrange | positioned at the short side of the light-emitting device 10 light-guide plate 20, the length which arrange | positions LED12 becomes short. For this reason, the attachment work of the LED 12 can be simplified, and members such as wiring for supplying power to the LED 12 can be reduced. As a result, the manufacturing cost can be reduced.

  In addition, since the LEDs 12 are not arranged in the longitudinal direction of the light guide plate 20, the frame size along the longitudinal direction of the light guide plate 20 can be reduced. As a result, the light guide plate 20 can be slimmed and the design can be improved. Further, even when a plurality of light guide plates 20 are arranged side by side, the LEDs 12 do not get in the way. Therefore, application to various types of products is possible.

  On the other hand, in the light emitting device 10 using this type of light guide plate 20, when the light guided through the light guide plate 20 has a light spread in a direction parallel to the end face 20a on which the light is incident, A conventional light guide plate having a flat exit surface b has a problem that light leakage from the long side of the light guide plate increases.

  Therefore, in the present embodiment, a plurality of streak-like uneven bodies T are formed on the exit surface 20b of the light guide plate 20 along a direction perpendicular to the end surface 20a on which light is incident. As a result, the straightness of the light guided through the light guide plate 20 by the plurality of streaky uneven shapes T increases, and the spread of the light in the direction parallel to the end surface 20a on which the light is incident is suppressed. And light leakage from the long side can be reduced.

  Further, it is possible to prevent the change in chromaticity from becoming larger than when the reflective tape is attached to the side surface of the light guide plate 20.

  Therefore, it is possible to provide the light emitting device 10 that can suppress light leakage from the side end face of the light guide plate 20 and can save power.

  Moreover, in the light-emitting device 10 of this Embodiment, it is preferable that the length of the long side in the light-guide plate 20 is 2 times or more of the length of a short side.

  Thereby, when the length of the long side in the light guide plate is twice or more than the length of the short side, the light spread in a direction parallel to the end surface on which the light is incident occurs in a long range, The energy loss of light increases. For this reason, especially in such a case, the effect of suppressing power leakage from the side end face of the light guide plate and saving power is great.

  Moreover, in the light-emitting device 10 of this Embodiment, the cross-sectional shape of the several streaky uneven | corrugated shaped body T in the output surface 20b of the light-guide plate 20 is arch shape or circular arc shape. Thereby, light straightness can be improved rather than the uneven | corrugated shape comprised by the polygon like a triangular shape.

  In the light emitting device 10 according to the present embodiment, the combination of the light guide plate 20 and the plurality of LEDs 12 provided on at least one end surface 20a on the short side of the light guide plate 20 is the long side of the adjacent light guide plate 20. It can be assumed that a plurality of sets are arranged so as to face each other. Thereby, a large light-emitting device can be realized.

  Further, in the conventional light guide plate having no streak-like uneven body T on the exit surface 20b of the light guide plate 20, light straightness is low, and thus light leakage occurs from the long side. For this reason, bright lines are generated at the joints between the adjacent light guide plates 20 and 20, and the joints become conspicuous, so that the quality of the lighting device is lowered.

  On the other hand, in the light emitting device 10 of the present embodiment, since the LED 12 does not exist on the long side of the light guide plate 20, the joining of the light guide plates 20 and 20 is not hindered, and the output surface 20b has a streak. When the concavo-convex shaped body T is present, the light straightness is enhanced. As a result, the joint between the light guide plates 20 does not stand out.

  The information display device 1 according to the present embodiment includes the light emitting device 10 according to the present embodiment.

  According to said structure, the information display apparatus 1 consists of what used the light-emitting device 10 of this Embodiment as a backlight for irradiating the information display part 3 from a back surface. As a result, the information display device 1 of the present invention can be used as an advertisement panel, a signboard, a sign panel, a guide panel, or a poster panel.

  Further, the lighting device of the present embodiment includes the light emitting device 10 of the present embodiment. Therefore, the light emitting device 10 of the present embodiment can be used as a lighting device for illuminating the room or the outdoors. For example, there is use as surface illumination of the light guide plate 20 that is assumed to be incorporated in a door or the like.

  It should be noted that 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 each of the embodiments. The form is also included in the technical scope of the present invention.

  The present invention relates to a light emitting device, an information display device, and a lighting device including a side edge (also referred to as a sidelight) type light guide plate that emits light from an LED in a planar shape by a light guide plate. It can be applied to a signboard, a sign panel, a guidance panel, or a poster panel. The information to be displayed includes advertisement contents such as product photos, designs, product names, and company names, advertisement items including advertisement contents, guidance items such as information signs, and notes.

DESCRIPTION OF SYMBOLS 1 Information display apparatus 3 Information display part 10 Light-emitting device 12 LED (light emitting diode)
15 Light source unit 16 Optical path conversion unit 17 Optical sheet 20 Light guide plate 20a End surface 20b Outgoing surface 20c Lower surface h Uneven height H Thickness h / P Aspect ratio L Longitudinal length P Pitch T Uneven shape
W Short width

Claims (6)

A light guide plate that has a rectangular planar shape and emits light incident in a direction perpendicular to the end surface from at least one of a pair of opposing end surfaces on the short side, and a plurality of light incident on the light guide plate In a light emitting device comprising a light emitting diode of
The light emitting device according to claim 1, wherein a plurality of streaky irregularities along a direction perpendicular to an end face on which the light is incident are formed on an emission surface of the light guide plate.   The light emitting device according to claim 1, wherein the length of the long side of the light guide plate is at least twice the length of the short side.   3. The light emitting device according to claim 1, wherein the plurality of streaky irregularities on the exit surface of the light guide plate has a cross-sectional shape of an arc shape or an arc shape.   A plurality of combinations of the light guide plate and a plurality of light emitting diodes provided on at least one end face on the short side of the light guide plate are arranged such that the long sides of the adjacent light guide plates face each other. The light-emitting device according to claim 1, 2 or 3. An information display device comprising the light emitting device according to claim 1,
An information display device, wherein an information display unit is provided on a light emission surface of the light emitting device.   An illuminating device comprising the light emitting device according to claim 1.

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