JP2007141735A - Double-sided light-emitting panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double-sided light-emitting panel allowing its thickness to be reduced even when the size of a light guide plate is increased, and excelling in aesthetic appearance. <P>SOLUTION: This double-sided light-emitting panel 100 includes: the light guide plate 11; a light source arranged on a side end surface 11a of the light guide plate 11; and a light reflecting member 23 for reflecting light from the light source toward the side end surface 11a of the light guide plate 11. The double-sided light-emitting panel is characterized in that the light guide plate 11 has a structure where a light diffusion material is uniformly mixed in a transparent substrate or uniform light diffusion layers are formed on both surfaces of the transparent substrate, and light entered from the side end surface 11a is emitted from both surfaces perpendicular to the entering direction; the light source comprises a plurality of plasma lamps 22; the plurality of plasma lamps 22 are arranged to run in the longitudinal direction thereof along the longitudinal direction of the side end surface 11a of the light guide plate 11 to constitute lamp lines; the plurality of lamp lines are arranged on the side end surface 11a; and the end positions of the plasma lamps adjacent to each other in the line direction are arranged by being shifted with respect to each other along the longitudinal direction of the side end surface 11a in the range of 1/3 to 1/2 of the length of the plasma lamps 22. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a double-sided light-emitting panel, and more particularly to a double-sided light-emitting panel that is thin and can be increased in size and that can obtain a sufficient amount of light.

  Conventionally, for example, Patent Literature 1 discloses an edge light type light emitting panel using a light guide plate that emits light incident from a side end surface to a surface orthogonal to the incident direction.

  Further, Patent Document 2 discloses a light guide plate capable of double-sided light emission in which light incident from a side end surface is emitted from both surfaces orthogonal to the incident direction by a single light guide plate.

Conventionally, a cold cathode lamp (CCFL) is exclusively used as a light source of an edge light type light emitting panel using such a light guide plate.
Utility Model Registration No. 3076767 Japanese Patent No. 270312

  Since the number of cold cathode lamps generally requires one inverter per two, the number of inverters increases correspondingly as the number of arranged cold cathode lamps increases. For this reason, when forming a large panel, the number of cold cathode lamps inevitably increases, and the number of inverters also increases, resulting in an increase in the size of the panel.

  If this inverter is arranged in the frame part where the cold cathode lamp around the light guide plate is arranged, the frame part is extremely enlarged by the inverter, and a thick frame is provided around the thin light guide plate. It would be extremely detrimental to aesthetics.

  In general, it is necessary to place the inverter as close as possible to the cold cathode lamp from the viewpoint of voltage loss and stable light emission. Depending on the number of cold cathode lamps and the size of the light guide plate, the inverter may be separated from the cold cathode lamp by the ceiling or under the floor. And it may be difficult to embed in a wall or the like.

  Therefore, in the conventional light emitting panel, it is difficult to increase the size of the panel if priority is given to the arrangement of the inverter, and if priority is given to the increase in size of the panel, the degree of freedom of arrangement of the inverter is greatly restricted, and the thin and excellent aesthetics. There was a problem that it was difficult to obtain a light-emitting panel.

  Therefore, if the number of cold cathode lamps is minimized in order to minimize the number of inverters even if the size of the light guide plate is increased, it is necessary to irradiate the light guide plate almost uniformly with a small number of lamps, as shown in FIG. In addition, the cold cathode lamps 300 disposed adjacent to each other on the side end surface of the light guide plate 200 must be spaced apart from each other, and this corresponds to a non-light emitting region between the upper and lower cold cathode lamps 300. As a result, the dark portion 400 is formed on the light guide plate 200, and there is a problem that the light emission unevenness is conspicuous.

  In particular, when light is emitted from both sides of the light guide plate, it requires a larger amount of light than when light is emitted from only one side, so a panel using conventional cold cathode lamps is thin and has a large size that can emit light evenly. The panel could not be constructed.

  The present invention has been made in view of such conventional circumstances, and an object of the present invention is to provide a double-sided light-emitting panel that can be thinned and has excellent aesthetics even when the size of the light guide plate is increased.

  The other subject of this invention becomes clear by the following description.

  The above problems are solved by the following inventions.

(Claim 1)
A double-sided light-emitting panel comprising a light guide plate, a light source disposed on a side end surface of the light guide plate, and a light reflecting member that reflects light from the light source toward the side end surface of the light guide plate,
In the light guide plate, a light diffusing material is uniformly mixed in a transparent substrate, or a uniform light diffusion layer is provided on both surfaces of the transparent substrate, and light incident from the side end surface is reflected from both surfaces orthogonal to the incident direction. Having a configuration to emit,
The light source is composed of a plurality of plasma lamps, and a plurality of plasma lamps are arranged so that the length direction of the plasma lamps is along the length direction of the side end face of the light guide plate. A plurality of rows are arranged on the side end face and the end positions of the plasma lamps adjacent to each other in the row direction are along the length direction of the side end face within a range of 1/3 to 1/2 of the length of the plasma lamp. A double-sided light emitting panel characterized by being displaced from each other.

(Claim 2)
The double-sided light emitting panel according to claim 1, wherein the light source is provided on each of opposite end surfaces of the light guide plate.

(Claim 3)
The double-sided light-emitting panel according to claim 1 or 2, wherein each plasma lamp is subjected to insulation treatment at the external electrode portions at both ends thereof.

  ADVANTAGE OF THE INVENTION According to this invention, even if the size of a light-guide plate is enlarged, the double-sided light emission panel which can be reduced in thickness and is excellent in the beauty | look can be provided.

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

  FIG. 1 is a front view of a double-sided light emitting panel according to the present invention, and FIG. 2 is a partial cross-sectional view of the double-sided light emitting panel according to the present invention. In the figure, 100 is a double-sided light emitting panel, 1 is a light emitting unit, and 2 is a light source unit provided at both ends of the light emitting unit 1. Here, an example in which the double-sided light emitting panel 100 is used as an advertising panel is shown.

  As shown in FIG. 2, the light emitting unit 1 has transparent acrylic plates 12 and 12 arranged on both surfaces of the light guide plate 11, respectively, and advertising media 3 made of a Colton sheet or the like on each surface of the acrylic plates 12 and 12. Is attached.

  In the present invention, the light guide plate 11 is formed of a substrate in which a light diffusion material is uniformly mixed in a transparent substrate material or a substrate in which uniform light diffusion layers are provided on both surfaces of the transparent substrate.

  As the transparent substrate used for the light guide plate 11, it is preferable to use a highly transparent substrate such as polymethyl methacrylate, (meth) acrylic acid ester copolymer, polycarbonate, polystyrene, polyvinyl chloride, or glass.

  As the light diffusing material mixed in the transparent substrate material, it is preferable to use a transparent or white pigment so that unevenness does not appear as the distance from the light source increases. As a transparent pigment, natural pigments such as inorganic pigments such as natural or synthetic silica, glass beads and diamond, organic pigments such as acrylic resin, styrene resin, silicon resin and benzoguanamine resin, rice starch and corn starch can be used. Further, as the white pigment, titanium oxide, zinc oxide, barium sulfate, calcium carbonate, magnesium carbonate, aluminum hydroxide, talc, clay and the like can be used. These pigments can be used alone or in combination of two or more.

  When a substrate is prepared by mixing a light diffusing material in a transparent substrate material, it is important that the light diffusing material is uniformly mixed in the transparent substrate material so as not to be uneven. After the light diffusing material is uniformly kneaded into the transparent substrate material, it is molded into a plate-like thickness by a known molding method such as extrusion molding or cast molding.

  Although the addition amount of a light-diffusion material changes also with the thickness of the light-guide plate 11, when setting thickness to 2-20 mm, it is preferable to set it as 0.000005-0.1 weight% with respect to transparent substrate material solid content.

  When the light guide plate 11 is formed of a substrate having a uniform light diffusion layer on both surfaces of the transparent substrate, a light diffusing material-containing paint or light diffusing material-containing ink is applied or printed on both surfaces of the transparent substrate. Thus, a substrate can be created. The light diffusing material-containing paint or the light diffusing material-containing ink can be prepared by uniformly dispersing and adjusting the light diffusing material in a transparent resin by a known method. In this case, transparent resins include acrylic such as polymethyl methacrylate and (meth) acrylic acid ester copolymer, styrene, urethane, epoxy, vinyl, polyertel, cellulose, polyamide, etc. It can be preferably used. Moreover, in order to improve dispersibility and applicability, additives such as a dispersant and a leveling agent can be added to the paint or ink as necessary.

  A transparent substrate is created by uniformly coating or printing the thus prepared paint or ink on a transparent substrate. As a coating or printing method, a known method such as a bar coating method, a roll coating method, a spray coating method, a coating method such as a dip coating method, a full surface printing method such as silk screen printing, offset printing, or gravure printing should be adopted. Can do.

  The addition amount of the light diffusing material in these paints or inks varies depending on the refractive index of the pigment, the thickness of the coating film or the printing, but when the coating or printing thickness is in the range of 1.0 to 20.0 μm, it is approximately the substrate. It can be 0.1-10.0 weight% with respect to material solid content.

  Moreover, a uniform light-diffusion layer can also be provided on both surfaces of a transparent substrate by performing a roughening process uniformly on both surfaces of a transparent substrate. In this case, the light diffusing layer can be obtained by uniformly roughening both surfaces of the transparent substrate by sand blasting or embossing.

  When the surface is roughened by embossing or other embossing, the embossing may be performed at the time of molding the substrate, or the transparent substrate may be once molded and then embossed using heat. In this case, in order to improve the mold pushability, a resin having a good mold pushability may be applied in advance to the transparent substrate and then stamped.

  Furthermore, the light diffusing layer can also be prepared by transferring a transfer layer having a uniform light diffusing surface to both surfaces of the transparent substrate. In this case, a transfer layer having a uniform light diffusing surface is coated on another substrate in advance, and the transfer layer can be transferred to a transparent substrate. The transfer layer may be used by directly dispersing a light diffusing material in a transferable resin, or a light fine diffusion layer in which a light diffusing material is dispersed in a resin having no transferability and a transferable resin layer. A layer structure can also be used. In addition, a transparent transfer layer or a transfer layer composed of two layers, a non-transferable resin layer and a transferable resin layer, is applied in advance to a base material that has been subjected to a roughening process such as sandblasting so as to obtain a predetermined degree of light diffusion. It may be applied and transferred to a transparent substrate. In this case, since the rough surface of the substrate is embossed by the transfer layer, it is not necessary to add a light diffusing agent.

  As the substrate on which the transfer layer is formed in advance, a film or sheet such as polyethylene terephthalate, polycarbonate, polyethylene, polypropylene, acrylic, vinyl chloride, and resin-coated paper can be used. These films or sheets are preferably subjected to a release treatment with a silicon resin or the like in order to improve transferability.

  The transfer resin used for the transfer layer includes polyamide-based, polyester-based, ethylene-vinyl acetate-based hot melt adhesives, natural or synthetic waxes, ethylenically unsaturated monomers or oligomers, photopolymerization initiators and binders. The photopolymerizable composition etc. which become can be used. In addition, when the transfer layer and the light diffusing layer have a two-layer structure, the light diffusing layer is made of acrylic such as polymethyl methacrylate, (meth) acrylate ester copolymer, styrene, urethane, epoxy, The above light diffusing material is dispersed in a vinyl resin, polyester resin, cellulose resin, polyamide resin or the like, and the transfer layer is an acrylic resin, vinyl resin, silicon resin, epoxy resin in addition to the transferable composition described above. Pressure sensitive adhesives such as urethanes and rubbers, and adhesives can be used.

  As the light diffusing material that is uniformly added to these transferable compositions to adjust the degree of light diffusion, the same materials as described above can be used, and the same method as described above is adopted as the surface roughening treatment method. it can.

  Moreover, the transparent substrate which has a light-diffusion layer can also be created by sticking the base material produced so that it may have a uniform light-diffusion surface beforehand on both surfaces of a transparent substrate. In this case, a resin film or sheet having a light diffusibility so as to have a predetermined light diffusion degree is selected from polyamide, polyester, acrylic, vinyl, silicon, epoxy, urethane, rubber, ethylene, It can create by bonding by transparent adhesives or adhesives, such as a photopolymerizable composition which consists of a photopolymerizable unsaturated monomer or oligomer, a photoinitiator, and a binder.

  As a method for imparting light diffusibility to the transparent resin film or sheet, the same light diffusing material-containing paint or light diffusing material-containing ink as described above is applied or printed, or the light diffusing material is contained in the transparent resin film or sheet material. It is possible to employ a method such as kneading and mixing the materials uniformly or uniformly roughening the transparent resin film or transparent plate by sandblasting or the like.

  As the transparent resin film, it is preferable to use a highly transparent film such as polyethylene terephthalate, polycarbonate, or acrylic, and a thin film is particularly preferable in order to increase luminance.

  When creating a transparent substrate by bonding a transparent resin film or a transparent plate and a transparent substrate with a pressure-sensitive adhesive or adhesive having a predetermined degree of light diffusion, the transparent resin film is the same as the transparent resin film described above. It is preferable to use a highly transparent film such as polyethylene terephthalate, polycarbonate, or acrylic, and a thin film is particularly preferable in order to increase luminance.

  The transparent plate is preferably a highly transparent plate, and acrylic, polycarbonate, styrene, polyvinyl chloride and glass plates can be used. The transparent resin film and the transparent plate and the transparent substrate are made to have a predetermined light diffusion. When pasting with a pressure sensitive adhesive or adhesive, photopolymerization starts with polyamide, polyester, acrylic, vinyl, silicon, epoxy, urethane, rubber, ethylenically unsaturated monomer or oligomer The light diffusing material is uniformly dispersed in a pressure-sensitive adhesive or adhesive such as a photopolymerizable composition comprising an agent and a binder.

  Any one of these methods for producing the transparent substrate may be used, but any two or more methods may be used in combination as required.

  The light guide plate 11 may be the light guide plate described in Japanese Patent No. 27031212.

  Transparent acrylic plates 12 and 12 are provided on both surfaces of the light guide plate 11, respectively. The use of the acrylic plates 12 and 12 further diffuses the light from the light emitting surfaces 11b and 11b on both sides of the light guide plate 11, and attaches the advertising media 3 to the light guide plate 11 that is particularly roughened on both sides. When it does, it makes a sticking surface smooth and can provide preferably in this invention.

  In the light emitting unit 1, the side end surface 11 a of the light guide plate 11 is a light incident surface, and the light source unit 2 is disposed on the side end surface 11 a of the light guide plate 11. Although FIG. 1 shows a case where the light source unit 2 is disposed on each of the left and right ends of the light emitting unit 1, that is, the left and right end surfaces of the light guide plate 11, only one of them may be provided. In addition, light leakage tape or the like is adhered to the side end surface of the light guide plate 11 where the light source unit 2 is not disposed to prevent light leakage.

  The light source section 2 is provided with a substantially U-shaped frame body 21, and a plurality of plasma lamps 22 are disposed as light sources inside the frame body 21.

  The plasma lamp 22 is also called an external electrode fluorescent lamp or an EEFL (External Electrode Fluorescent Lamp). Unlike a general fluorescent lamp, the electrode is provided outside the tube, and a special electron that emits light by applying a voltage to the external electrode. This is a discharge type cold tube.

  A plurality of plasma lamps 22 are arranged on each side end surface 11a so that the length direction thereof is along the length direction (vertical direction in FIG. 1) of the side end surface 11a of the light guide plate 11, thereby constituting a lamp row. Yes.

  FIG. 3 shows a state in which the plasma lamp 22 of one light source unit 2 is viewed from the direction A in FIG. As shown in the figure, the plasma lamps 22 are arranged in a plurality of rows on the one end face 11a. The position of the end portion 22a of the plasma lamp 22 adjacent in the column direction is in the range of 1/3 to 1/2 of the length of the plasma lamp 22 along the length direction of the side end face 11a of the light guide plate 11. Are displaced from each other.

  Generally, since an external electrode is provided on the surface of each end portion 22a of the plasma lamp 22, it is difficult to reduce the distance between the end portions 22a of the adjacent plasma lamps 22 in order to avoid interference between the plasma lamps 22. It is. However, the positions of the end portions 22a of the plasma lamps 22 adjacent to each other in the column direction are shifted from each other along the length direction of the side end surface 11a of the light guide plate 11 so that the external electrodes of the end portions 22a are connected to each other. The distance between the adjacent plasma lamps 22 can be made as close as possible, and the thickness of the light source unit 2 can be reduced even if a plurality of lamp rows are formed.

  Further, as a result of shifting the position of the end portion 22a of the adjacent plasma lamp 22, the shortage of light quantity between the upper and lower plasma lamps 22 in one lamp row can be compensated by the plasma lamps 22 in the adjacent lamp row. Therefore, a substantially uniform amount of light can be ensured along the length direction of the light guide plate 11, and the uneven light emission near the end 22a can be made inconspicuous.

  Even if the amount of displacement of the position of the end portion 22a of the plasma lamp 22 is less than 1/3 or more than 1/2 of the length of the plasma lamp 22, the vicinity between the end portions 22a of the upper and lower plasma lamps 22 The light emission unevenness at becomes more noticeable.

  From the viewpoint of ensuring the prevention of interference between the plasma lamps 22, it is preferable that each plasma lamp 22 is subjected to an insulation treatment at an external electrode arrangement site provided at the end 22 a. The code | symbol 22b in FIG. 3 has shown the insulating part of the edge part 22a. For example, when the heat-shrinkable tube made of an insulating material having heat-shrinkability is used as the insulating portion 22b and is heat-shrinked so as to be in close contact with the outer surface of the end portion 22a, the diameter of the end portion 22a of the plasma lamp 22 is more than necessary. It is preferable from the viewpoint that the distance between adjacent plasma lamps 22 can be reduced.

  A reflection plate 23 is provided on the inner surface of the frame body 21 so that light emitted from each plasma lamp 22 is reflected toward the side end surface 11 a of the light guide plate 11. The light incident on the light guide plate 11 from the side end surface 11a is emitted from the light emitting surfaces 11b and 11b on both surfaces by the light diffusion effect of the light guide plate 11, thereby causing the advertising media 3 on each surface to emit a sufficient amount of light without uneven light emission. Illuminate from the back.

  As shown in FIG. 1, each plasma lamp 22 is connected in parallel to an inverter 24 by a wiring 25. In FIG. 1, one inverter 24 is provided in each of the left and right light source units 2, and each inverter 24 controls driving of a plurality of plasma lamps 22.

  In the conventional panel using a cold cathode lamp, the number of lamps cannot be increased due to the number of inverters, and a thin and large-sized panel is impossible, but one plasma lamp 22 is provided. Since the inverter 24 can turn on more than a dozen, a sufficient amount of light can be obtained.

  The number of the plasma lamps 22 arranged on the one side end face 11a can be appropriately determined according to the size of the light guide plate 11, but according to the experiments of the present inventors, the tube diameter is 2.6 mm and the length is 400 mm. When a plasma lamp was used, it was confirmed that 14 lamps could be lit by one inverter. Thus, when the end portions 22a of the adjacent plasma lamps 22 are shifted from each other within a range of ½, the plasma lamp 22 can be formed without any problem even if the light guide plate 11 having the side end surface 11a of 3000 mm is used. A large-sized double-sided light-emitting panel that can be lit and emit light with a sufficient amount of light without unevenness could be constructed.

  The tube diameter of the plasma lamp 22 can be appropriately determined according to the thickness of the light guide plate 11, but from the viewpoint of reducing the thickness of the panel, it is preferable to use a tube with a small tube diameter of 2 mm to 8 mm. It is preferable. In general, a thin tube diameter is inferior in light intensity to a thick tube. However, in the present invention, a plurality of lamp rows composed of a plurality of plasma lamps 22 are arranged on one side end face 11a, so that the tube diameter of the plasma lamp 22 is small. Even a thing can obtain a sufficient amount of light.

  The thickness of the light guide plate 11 is not particularly limited, but at least about 10 mm is sufficient from the viewpoint of strength and thinning.

  As shown in FIG. 2, the plasma lamp 22 disposed on the one end face 11a of the light guide plate 11 is not limited to a mode in which two lamp arrays are arranged in parallel so as to be substantially parallel to the side end face 11a. As shown to Fig.4 (a), the aspect arrange | positioned diagonally with respect to the side end surface 11a may be sufficient.

  In the former case, since each lamp row is substantially equidistant with respect to the side end face 11a, even when the wide light guide plate 11 having a long distance between the opposing side end faces 11a is used, both sides can emit light evenly. Is preferable. Moreover, since the thickness of the light source part 2 can be made small in the latter case, it is preferable when aiming at thickness reduction and the aesthetic improvement of a panel.

  In addition, the number of lamp rows made up of the plurality of plasma lamps 22 arranged on the one end face 11a is not limited to two rows, and may be three or more rows.

  FIG. 5 shows an aspect of three lamp rows. FIG. 5 shows a state in which the light guide plate 11 and the plasma lamp 22 are viewed from the same direction as the direction A shown in FIG.

  FIG. 5A shows the position of the end portion 22a of each plasma lamp 22 in the lamp rows 22A and 22B between the two rows of lamp rows 22A and 22B with the end portion 22a positioned substantially at the same position. A lamp row 22C composed of plasma lamps 22 in which the position of the end 22a is shifted is arranged. In FIG. 5B, the positions of the end portions 22a of the plasma lamps 22 in all three lamp rows 22A to 22C are shifted from each other.

  By arranging the plasma lamps 22 in this way, a sufficient amount of light can be secured by using the plasma lamps 22 having a small tube diameter even when the thickness of the light guide plate 11 increases.

  When the lamp rows are three rows, the lamp rows 22A to 22C may be juxtaposed so as to be substantially parallel to the side end surface 11a of the light guide plate 11, and in order to keep the thickness of the light source unit 2 small, As shown in FIG. 4B, for example, only one lamp row 22C may be arranged away from the side end face 11a.

  The double-sided light emitting panel 100 according to the present invention can be stretched between the ceiling R and the floor G using the advantage that it can be enlarged as shown in FIG. In this case, by disposing the inverter 24 inside the ceiling R or inside the floor G, the appearance can be clearly seen.

  Further, as shown in FIG. 7, a self-standing panel can be obtained by standing the double-sided light emitting panel 100 on the base 4. In this case, the inverter 24 may be disposed inside the base 4. According to the present invention, since a dozen or so plasma lamps 22 can be lit by a single inverter 24, the number of inverters 24 is large even in a large double-sided light emitting panel 100 using a large number of plasma lamps 22. Since it does not increase so much, it is not necessary to increase the size of the base 4 more than necessary even as a self-supporting panel, and a self-supporting double-sided light emitting panel excellent in aesthetics can be obtained.

  Further, although not shown, the double-sided light emitting panel 100 can be hung from the ceiling or provided in a protruding manner on a pillar or wall surface.

  In the above description, the mode of using as an advertising panel by sticking the advertising media 3 to both surfaces of the light emitting unit 1 has been shown. However, the double-sided light emitting panel 100 according to the present invention is not limited to use as an advertising panel, It can be used in various fields. For example, the double-sided light emitting panel 100 can be used as a single partition wall (partition) or a bright door by connecting one or more double-sided light emitting panels 100. In this case, it is also preferable that image sheets such as photographs are pasted on both sides of the light emitting unit 1 in addition to the advertising media.

  In addition, it can be used as various information display boards such as building tenant guidance, road maps, timetables for transportation such as buses and trains, and stops (stops) for transportation such as buses.

Front view of a double-sided light emitting panel according to the present invention Partial cross-sectional view of a double-sided light emitting panel according to the present invention The figure which shows the state which looked at the plasma lamp from A direction in FIG. The figure which shows the preferable aspect of arrangement | positioning of the plasma lamp which concerns on this invention The figure which shows the preferable aspect of arrangement | positioning of the lamp row which concerns on this invention. The figure which shows the preferable aspect of the double-sided light-emitting lamp which concerns on this invention. The figure which shows the other preferable aspect of the double-sided light emission lamp which concerns on this invention. Figure showing a conventional light-emitting panel

Explanation of symbols

1: Light emitting part
2: Light source unit 11: Light guide plate 11a: Side end surface 11b: Light exit surface 12: Acrylic plate 21: Frame body 22: Plasma lamp
22a: End 22b: Insulating part 22A, 22B 22C: Lamp array 23: Reflector 24: Inverter 25: Wiring 100: Double-sided light emitting panel

Claims (3)

A double-sided light-emitting panel comprising a light guide plate, a light source disposed on a side end surface of the light guide plate, and a light reflecting member that reflects light from the light source toward the side end surface of the light guide plate,
In the light guide plate, a light diffusing material is uniformly mixed in a transparent substrate, or a uniform light diffusion layer is provided on both surfaces of the transparent substrate, and light incident from the side end surface is reflected from both surfaces orthogonal to the incident direction. Having a configuration to emit,
The light source is composed of a plurality of plasma lamps, and a plurality of plasma lamps are arranged so that the length direction of the plasma lamps is along the length direction of the side end face of the light guide plate. A plurality of rows are arranged on the side end face and the end positions of the plasma lamps adjacent to each other in the row direction are along the length direction of the side end face within a range of 1/3 to 1/2 of the length of the plasma lamp. A double-sided light emitting panel characterized by being displaced from each other.   The double-sided light emitting panel according to claim 1, wherein the light source is provided on each of opposite end surfaces of the light guide plate. The double-sided light-emitting panel according to claim 1 or 2, wherein each plasma lamp is subjected to insulation treatment at the external electrode portions at both ends thereof.

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