JP2008299117A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device which is excellent in visibility of a display portion and simple in structure and can suppress the occurrence of unnecessary light due to dust, etc. adhering to a light transmission plate. <P>SOLUTION: The display device 10 includes: the transparent light transmission plate 1; a light source 4 provided on the side of the end surface 1a of the light transmission plate 1; and protective plates 5 and 6. In the light transmission plate 1, the display portion comprising a plurality of concave portions 2 having a reflection surface 2a reflecting light emitted from the light source 4 to the side of a front surface 1b is formed and the protective plates 5 and 6 are totally adhered to the front face 1b and rear face 1c of the light transmission plate 1 by transparent low-refractive-index resins 7 and 8 having a refractive index lower than that of the light transmission plate 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a display device used for a display or the like.

  In recent years, LEDs (light-emitting diodes) have been increasingly used for various purposes as high-efficiency, long-life light sources. For example, a display device having a display unit in which LED elements are provided in a predetermined arrangement between two transparent glass plates is known (for example, see Patent Document 1).

  LED is a point light source with directivity, and since it is limited to use as spot illumination by itself, it may be used as a linear or planar light source in combination with a light guide such as a transparent resin plate. Many. Examples include liquid crystal backlights and advertising light panels.

  In addition, as a display device having transparency and excellent design properties, there is a display device in which a surface of a light guide plate is roughened by laser processing or etching to form a display portion that forms a figure, a logo, or the like.

This display device emits light from a light source provided on an end face of a light guide plate to raise a display unit, and is used for a display or the like.
European Patent No. 099199

  In the display device having the roughened display unit, since light is scattered by the display unit, the luminance per unit area of the display unit is lowered and the visibility becomes insufficient.

  In this display device, a protective plate for protecting the light guide plate may be provided. However, dust may enter the gap between the light guide plate and the protective plate, or the mixed dust may damage the light guide plate. There is. Thus, when dust adheres to the light guide plate or the light guide plate is scratched, light in the light guide plate leaks from there, and unnecessary light may be visually recognized.

  In order to suppress the generation of such unnecessary light, it has been required to manufacture in an environment free of dust and to have a structure with excellent sealing performance. In addition, it is necessary to use a member having no burrs or scratches on the end face as a constituent member of the display device. In addition, unless the display device has a completely waterproof structure, the light intensity of the display portion is reduced due to condensation due to the influence of moisture in the air.

  The present invention has been made in view of the above, and provides a display device that has excellent visibility of a display unit and can suppress generation of unnecessary light due to dust or the like attached to a light guide plate with a simple structure. With the goal.

  In order to achieve the above object, a display device according to claim 1 of the present invention is provided with a transparent light guide plate and at least one end face side of the light guide plate, and emits light toward the light guide plate. Two light sources, a plurality of concave portions formed on one surface side of the light guide plate and reflecting incident light to the other surface side of the light guide plate, and a transparent having a lower refractive index than the light guide plate. A transparent first protective plate provided by being bonded to the entire surface of the light guide plate with a low refractive index resin, and provided to be bonded to the other surface of the light guide plate with the low refractive index resin. And a transparent second protective plate.

  A display device according to a second aspect of the present invention includes a transparent light guide plate, at least one light source that is provided on at least one end face side of the light guide plate and emits light toward the light guide plate, and the light guide plate. A plurality of concave portions formed on one surface side of the light guide plate and having a reflection surface for reflecting incident light to the other surface side of the light guide plate; and provided on the surface of the one surface of the light guide plate; A first low refractive index layer made of a transparent low refractive index resin having a low refractive index, and a second low refractive index layer made of the low refractive index resin provided on the other surface of the light guide plate. And a transparent first protective plate provided by being adhered to the entire surface of the first low refractive index layer provided on the one surface of the light guide plate with an adhesive, and the other surface of the light guide plate. Provided on the second low-refractive index layer provided on the entire surface with a transparent adhesive. Characterized in that it comprises a and a transparent second protective plate.

  According to a third aspect of the present invention, in the display device according to the second aspect, the adhesive used for bonding the first protective plate is colored.

  The display device according to claim 4 of the present invention is the display device according to any one of claims 1 to 3, wherein the light guide plate is made of an acrylic resin, and the low refractive index resin is a silicone resin or It is a fluorine resin.

  The display device according to a fifth aspect of the present invention is the display device according to any one of the first to fourth aspects, wherein the plurality of recesses are any one or more of characters, symbols, figures, and patterns. It is arranged so that the combination of these may be displayed.

  The display device according to a sixth aspect of the present invention is the display device according to any one of the first to fifth aspects, wherein the angle of the reflection surface of the recess with respect to the one surface of the light guide plate is 45 degrees. It is more than 60 degree | times, It is characterized by the above-mentioned.

  A display device according to a seventh aspect of the present invention is the display device according to any one of the first to sixth aspects, wherein the concave portion has a substantially rectangular shape in plan view, and an aspect ratio thereof is 10: 1 to 1. : 1 up to a range.

  The display device according to an eighth aspect of the present invention is the display device according to any one of the first to seventh aspects, wherein at least some of the reflective surfaces of the plurality of concave portions are planar. It is characterized by being formed.

  The display device according to a ninth aspect of the present invention is the display device according to any one of the first to eighth aspects, wherein the light source extends along the extending direction of the light guide plate. It is characterized by being.

  According to a tenth aspect of the present invention, in the display device according to the ninth aspect, the light source includes a plurality of light emitting diodes arranged in a predetermined direction.

  In the display device of the present invention, a concave portion having a reflective surface is formed on one surface of the light guide plate, and light from the light source is reflected on the reflective surface of the concave portion. Since most of the light from the light source is reflected by the reflecting surface and is emitted in a substantially constant direction, the luminance is sufficiently high. For this reason, even when observing at a distance, excellent visibility is obtained.

  Also, by adhering the protective plate to the entire surface of the light guide plate using a low refractive index resin having a lower refractive index than that of the light guide plate, it is possible to prevent dust and the like from entering between the light guide plate and the protective plate. It is possible to prevent unnecessary light from being visually recognized due to leakage of light in the light guide plate due to adhered dust or the like.

  The best mode for carrying out the display device of the present invention will be described below with reference to the drawings.

  1 is a perspective view schematically showing a display device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the display device shown in FIG. 1, and FIG. 3 is an enlarged cross-sectional view of a main part of the display device shown in FIG. FIG. 4 is a plan view of a recess of the display device shown in FIG.

  As shown in FIGS. 1 and 2, the display device 10 according to the present embodiment includes a transparent light guide plate 1 and a light source 4 that is provided on the end surface 1 a of the light guide plate 1 and emits light toward the light guide plate 1. And transparent protective plates 5 and 6.

  As the light source 4, an LED, an LD (laser diode), or the like can be used. The light source 4 is preferably formed so as to extend along the extending direction of the light guide plate 1. In the example shown in FIGS. 1 and 2, the light guide plate 1 is formed to extend along the end surface 1 a on one side of the substantially rectangular light guide plate 1.

  As the light source 4, for example, a plurality of LEDs arranged in a direction along the end face 1a can be used. Moreover, the color of the light emitted from the light source 4 can be exemplified by white, red, green, blue, and the like, and can be appropriately selected according to the pattern formed by the recess 2. The light source 4 can also be provided on one and the other end surfaces of the light guide plate 1.

  The light guide plate 1 may be a transparent material, and a plate made of a synthetic resin such as an acrylic resin, a polycarbonate resin, a silicone resin, a cyclopolyolefin resin, or a glass plate is used. Among them, transparency and easy processing are used. An acrylic board is preferable from the standpoints of height.

  The thickness of the light guide plate 1 can be set to 0.5 mm to 10 mm, for example. Moreover, it is preferable that the light-guide plate 1 has the light transmittance which can see the background through.

  In the present invention, the term “transparent” means that the reflected light from the concave portion 2 is light transmissive. This definition is commonly used in the present invention.

  Protection plates 5 and 6 for protecting the light guide plate 1 are provided on the front surface 1b side and the back surface 1c side of the light guide plate 1, respectively. The protective plates 5 and 6 are made of a synthetic resin such as acrylic resin or polycarbonate resin, or a transparent material such as glass, and are formed in substantially the same shape as the light guide plate 1.

  The protective plates 5 and 6 are bonded to the entire surface of the light guide plate 1 on the front surface 1b and the back surface 1c with transparent low refractive index resins 7 and 8 having a refractive index lower than that of the light guide plate 1, respectively. The thickness of the low refractive index resins 7 and 8 can be set to 1 mm to 2 mm, for example.

  The low refractive index resins 7 and 8 prevent dust and the like from entering between the light guide plate 1 and the protective plates 5 and 6, and dust adheres to or is scratched on the front surface 1 b and the back surface 1 c of the light guide plate 1. In addition, the light in the light guide plate 1 is reflected at the interface with the light guide plate 1 to prevent light from leaking to the outside from positions other than the recesses 2 on the front surface 1b and the back surface 1c of the light guide plate 1. .

Moreover, it is preferable that the difference between the refractive index of the light guide plate 1 and the refractive indexes of the low refractive index resins 7 and 8 is not less than a predetermined value. For example, when the light guide plate 1 is an acrylic resin having a refractive index n ₁ = 1.49, the refractive index n ₂ of the low refractive index resins 7 and 8 is preferably 1.42 or less. Thereby, it is possible to prevent light that is not totally reflected at the interface between the light guide plate 1 and the low refractive index resins 7 and 8 from leaking to the outside. For example, when the material of the light guide plate 1 is an acrylic resin, as the material of the low refractive index resins 7 and 8, a silicone resin, a fluorine resin, or the like can be used as a material having a refractive index of 1.42 or less.

  On the back surface 1 c of the light guide plate 1, a display unit 3 including a plurality of recesses 2 is formed. As shown in FIGS. 2 and 3, the recess 2 has a reflection surface 2 a that reflects light emitted from the light source 4 and incident from the end surface 1 a to the surface 1 b side. The recess 2 is shaped so that light from the light source 4 strikes the reflecting surface 2a. In the present embodiment, the concave portion 2 has a substantially rectangular shape in plan view (see FIG. 4), and has a cross section that is a triangle with the reflective surface 2a as a hypotenuse (see FIG. 3).

  The concave portion 2 may be any structure as long as it is formed in the light guide plate 1 and reflects the light from the light source 4 toward the surface 1b, and the configuration is not limited to the illustrated example. For example, the reflecting surface may be a polygon (for example, trapezoid) or a sector having a square shape or more.

  When viewed in plan, the aspect ratio (aspect ratio) (average value) of the recess 2 is preferably in the range of 10: 1 to 1: 1, and more preferably in the range of 5: 1 to 1: 1. .

  As shown in FIG. 4, the aspect ratio means β1: β2. β1 is the planar view length (length in the light incident direction) of the oblique side 2b of the recess 2 shown in FIGS. 3 and 4, and β2 is the upper side 2c and the lower side 2d perpendicular to the light incident direction. Length.

  If the length β1 with respect to the length β2 is too large, the shape of the light from the concave portion 2 becomes nearly linear, which is not preferable because the transparency that is a characteristic of the display device 10 is impaired. If the length β1 with respect to the length β2 is too small, the brightness of the recess 2 is too low. Note that β2: β1 can also be considered as an aspect ratio.

  The aspect ratio refers to the ratio of the long side to the short side (long side: short side) of the rectangle having the minimum area that is inscribed in the plan view in plan view.

  The planar view shape of the recess 2 is not limited to the illustrated example, and may be a polygon such as a triangle or a pentagon, a circle, an ellipse, or the like.

  If the angle of inclination of the reflecting surface 2a with respect to the back surface 1c of the light guide plate 1 (angle α shown in FIG. 3) is too small, the angle of inclination of the emitted light also increases, and the visibility of the recess 2 when the display device 10 is viewed from the front. Decreases. If the inclination angle α is too large, the incident angle of light exceeds the critical angle and the proportion of light transmitted through the reflecting surface 2a increases, so that the light reflection efficiency decreases and the light use efficiency decreases.

  For this reason, the inclination angle α of the reflecting surface 2a is preferably 45 degrees or more and 60 degrees or less, and more preferably 50 degrees or more and 55 degrees or less. By setting the inclination angle α in the above range, the light reflection efficiency can be increased, and the reflected light can be emitted at an angle close to the surface 1b to improve the visibility of the recess 2.

  In the illustrated example, the reflecting surface 2a is planar, but at least a part of the reflecting surface may be planar, and a part may be configured by a curved surface. Moreover, you may make the shape of a reflective surface different in each reflective surface. If the reflecting surface is a curved surface, the emission angle of the reflected light may extend over a wide range. In this case, the concave portion 2 can be viewed from a wide range.

  Further, in order to increase the light reflection efficiency on the reflection surface 2a, it is desirable to form the surface of the reflection surface 2a smoothly.

  If the height of the recess 2 (height γ shown in FIG. 3) is too small, the visibility of the recess 2 is lowered, and if it is too large, it is not preferable in terms of transparency of the display device 10. Is preferably 0.1 mm to 5 mm, and more preferably 0.5 mm to 3 mm.

  The ratio (average value) of the height γ of the recess 2 to the thickness of the light guide plate 1 is preferably 1/10 to 1/1, and more preferably 1/5 to 2/3.

  When the planar view areas (β1 × β2) of all the recesses 2 are the same, the brightness of the reflected light in the recesses 2 far from the light source 4 tends to be lower than the reflected light in the recesses 2 close to the light source 4. . For this reason, it is preferable to make the brightness | luminance of the reflected light of the recessed part 2 uniform by enlarging the planar view area of the recessed part 2 according to the distance from the light source 4. FIG.

  The recesses 2 are preferably arranged so as to form letters, symbols, figures, patterns, or combinations of two or more thereof.

  As shown in FIG. 3, in the display device 10, light from the light source 4 can be incident on the light guide plate 1 from the end surface 1 a, reflected on the reflection surface 2 a of the recess 2, and emitted from the surface 1 b side. When viewed from the surface 1b side, the recess 2 is observed as a dot-like bright spot. In addition, by arranging the recesses 2 so as to form letters, symbols, figures, patterns, or a combination of two or more of these, the design composed of the arrangement of the recesses 2 is visually recognized by observing from the surface 1b side. .

  Most of the light from the light source 4 is reflected by the reflecting surface 2a and travels in a substantially constant direction (in the illustrated example, the direction perpendicular to the surface 1b), so that the luminance per unit area of the reflected light is sufficiently large. For this reason, even when observing at a distance, excellent visibility is obtained. Moreover, since the area of the recessed part 2 can be restrained small, the transparency of the display apparatus 10 is not impaired.

  In the display device 10, since the protective plates 5 and 6 are bonded to the light guide plate 1 by the low refractive index resins 7 and 8, dust, water vapor, or the like is generated between the light guide plate 1 and the protective plates 5 and 6. There is no invasion. For this reason, it can suppress that the light in the light-guide plate 1 leaks and unnecessary light generate | occur | produces due to the dust etc. which were attached to the surface 1b of the light-guide plate 1, and the back surface 1c, and a damage | wound. In addition, an effect of increasing the mechanical strength of the display device 10 can be obtained.

  Further, since the structure is simple, manufacturing is easy and advantageous in terms of cost. Furthermore, since the light guide plate 1 and the light source 4 are separate bodies, there is an advantage that it is easy to replace the light guide plate 1 with a light guide plate having a different display unit.

  Further, if the number of the concave portions 2 is increased and the light amount of the light source 4 is increased, not only a function as a display device but also a function as a planar illumination device can be provided.

  Next, an example of a method for forming the recess 2 of the display device 10 will be described with reference to FIGS.

  As shown in FIG. 5, a processing tool 13 in which a blade portion 12 is formed to protrude from the lower surface of the base portion 11 is used. The blade portion 12 has a shape corresponding to the recess 2, and the vertex angle (vertical angle δ shown in FIG. 5) of the blade portion 12 is preferably 10 to 40 degrees.

  In order to form the reflecting surface 2a smoothly, it is preferable that the inclined surface 12a of the blade portion 12 which is the surface forming the reflecting surface 2a is also formed smoothly.

  As shown in FIGS. 6 and 7, the processing tool 13 is lowered along the forming direction of the blade portion 12, the blade portion 12 is pushed into the back surface 1 c of the light guide plate 1, and the processing tool 13 is raised to raise the blade portion 12. Pull out.

  At this time, if one or both of the blade portion 12 and the light guide plate 1 are heated to a temperature equal to or higher than the softening point of the material of the light guide plate 1, the formation of the recess 2 is facilitated.

  Thereby, a concave portion 2 having a shape along the blade portion 12 is formed on the back surface 1 c of the light guide plate 1.

  By moving the processing tool 13 horizontally and repeating the same operation, the display unit 3 including a plurality of recesses 2 is formed.

  According to the manufacturing method using the processing tool 13, the concave portion 2 having an accurate shape can be formed. Moreover, the reflective surface 2a can be formed smoothly.

  Other manufacturing methods include cutting, press molding, injection molding, and the like. Among these, cutting, press molding, and injection molding have the advantage that the reflecting surface 2a can be formed relatively smoothly. Moreover, press molding and injection molding can be accurately formed even with a small recess 2. Further, since the cutting process does not require a mold, the manufacturing cost can be reduced, which is particularly advantageous in the case of processing a light guide plate having a large area or small-scale production.

(Modification)
FIG. 8 is a cross-sectional view of a display device according to a modification of the embodiment of the present invention. In addition, in the component of the display apparatus 20 of this modification shown in FIG. 8, the same number is attached | subjected about the same component as the display apparatus 10 shown in FIGS. 1-4, and detailed description is abbreviate | omitted.

  As shown in FIG. 8, in the display device 20 of this modification, a transparent low refractive index resin having a lower refractive index than that of the light guide plate 1 is coated on the front surface 1 b and the back surface 1 c of the light guide plate 1. Low refractive index layers 21 and 22 are respectively formed. The protective plates 5 and 6 are bonded to the entire surface of the low refractive index layers 21 and 22 formed on the light guide plate 1 by transparent general-purpose adhesives 23 and 24, respectively.

  Similarly to the above embodiment, when the light guide plate 1 is made of acrylic resin, the low refractive index layers 21 and 22 are made of silicone resin, fluorine resin, or the like having a lower refractive index than acrylic resin. be able to. The low refractive index layers 21 and 22 can be formed by a screen printing method, a dipping method, or the like. Moreover, as the adhesives 23 and 24, for example, an epoxy resin adhesive can be used.

  The low refractive index layers 21 and 22 reflect the light in the light guide plate 1 at the interface with the light guide plate 1 and prevent light from leaking to the outside from positions other than the recesses 2 on the front surface 1b and the back surface 1c of the light guide plate 1. suppress.

  As described above, in the display device 20 according to the present modification, the low-refractive index layers 21 and 22 are provided on the light guide plate 1, so that the general-purpose adhesives 23 and 24 can be used for bonding the protective plates 5 and 6. The same operational effects as those of the display device 10 according to the above embodiment can be obtained.

  The adhesive 24 for adhering the protective plate 6 provided on the back surface 1c side is not limited to being transparent, and may be a colored adhesive such as black or blue. Thereby, according to the display content of the display apparatus 20, a background color can be made into a desired color.

  The method for forming the recess 2 of the display device 20 according to this modification is the same as the method described with reference to FIGS. In addition, as shown in FIGS. 5-7, the recessed part 2 may be formed in the light-guide plate 1 in which the low refractive index layers 21 and 22 are not formed, and the low refractive index layers 21 and 22 may be formed after that. After forming the low refractive index layers 21 and 22 on the light guide plate 1, the concave portion 2 may be formed by the same method as described above.

  Specific examples of the present invention will be described below.

Example 1
A 1 m × 1 m × t 1 mm acrylic resin plate was used as the light guide plate 1, and the concave portion 2 having the reflective surface 2 a was formed at a desired position of the light guide plate 1 by the method shown in FIGS. Thereafter, a thermosetting silicone material with a refractive index of 1.41 (OF-127 manufactured by Shin-Etsu Chemical Co., Ltd.) is applied to both surfaces of the light guide plate 1, and glass protective plates 5 and 6 having a thickness of about 4 mm are adhered to the entire surface. did.

  And when white LED light was entered from the end surface 1a of the light-guide plate 1, the leakage light from places other than the reflective surface 2a of the recessed part 2 was not confirmed.

  In addition, when the light guide plate 1 to which the protective plates 5 and 6 are bonded is left outdoors for about one month and then white LED light is incident from the end face 1a of the light guide plate 1, in this case also, the reflection surface 2a of the recess 2 Leaked light from other places was not confirmed. This prevents dust and water vapor from entering between the light guide plate 1 and the protective plates 5 and 6 over a long period of time, and suppresses the generation of unnecessary light due to dust or the like attached to the light guide plate 1. It was confirmed that

(Example 2)
An acrylic resin plate of 1 m × 1 m × t 1 mm is used as the light guide plate 1, and a fluorinated acrylate material having a refractive index of 1.40 (Diffensa7710Z manufactured by Dainippon Kagaku Kogyo) is screen printed on both sides of the light guide plate 1. A film thickness was imparted and UV-cured to form low refractive index layers 21 and 22. Next, a concave portion 2 having a reflective surface 2a was formed at a desired position of the light guide plate 1 on which the low refractive index layers 21 and 22 were formed by the method shown in FIGS. Thereafter, an epoxy resin adhesive 1500 (made by Cemedine) is applied to both surfaces of the light guide plate 1 on which the low refractive index layers 21 and 22 are formed, and the glass protective plates 5 and 6 having a thickness of about 4 mm are applied to the entire surface. Glued.

  And when white LED light was entered from the end surface 1a of the light-guide plate 1, the result similar to Example 1 was obtained. Moreover, even after the light guide plate 1 to which the protective plates 5 and 6 were bonded was left outdoors for about one month, the same results as in Example 1 were obtained.

1 is a perspective view schematically showing a display device according to an embodiment of the present invention. It is sectional drawing of the display apparatus shown in FIG. It is a principal part expanded sectional view of the display apparatus shown in FIG. It is a top view of the recessed part of the display apparatus shown in FIG. It is process drawing which shows the method of forming the recessed part of the display apparatus shown in FIG. It is process drawing following a previous figure. It is process drawing following a previous figure. It is sectional drawing which shows the display apparatus in the modification of embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light guide plate 2 Recessed part 2a Reflecting surface 3 Display part 4 Light source 5,6 Protective plate 7,8 Low refractive index resin 10,20 Display device 21,22 Low refractive index layer 23,24 Adhesive

Claims (10)

A transparent light guide plate,
At least one light source provided on at least one end face side of the light guide plate and emitting light toward the light guide plate;
A plurality of recesses formed on one side of the light guide plate and having a reflective surface for reflecting incident light to the other side of the light guide plate;
A transparent first protective plate provided by being bonded to the entire surface of the light guide plate with a transparent low refractive index resin having a refractive index lower than that of the light guide plate;
And a transparent second protective plate provided on the other surface of the light guide plate by the low refractive index resin. A transparent light guide plate,
At least one light source provided on at least one end face side of the light guide plate and emitting light toward the light guide plate;
A plurality of recesses formed on one side of the light guide plate and having a reflective surface for reflecting incident light to the other side of the light guide plate;
A first low-refractive-index layer made of a transparent low-refractive-index resin having a refractive index lower than that of the light guide plate, provided on the one surface of the light guide plate;
A second low refractive index layer formed on the other surface of the light guide plate and made of the low refractive index resin;
A transparent first protective plate provided on the first low refractive index layer provided on the one surface of the light guide plate by being adhered to the entire surface with an adhesive;
A transparent second protective plate provided on the second low-refractive index layer provided on the other surface of the light guide plate by being adhered to the entire surface with a transparent adhesive. apparatus.   The display device according to claim 2, wherein the adhesive used for bonding the first protective plate is colored.   The display device according to claim 1, wherein the light guide plate is made of an acrylic resin, and the low refractive index resin is a silicone resin or a fluorine resin.   The plurality of recesses are arranged to display any one or more combinations of characters, symbols, figures, and patterns. Display device.   6. The display device according to claim 1, wherein the reflection surface of the concave portion has an angle with respect to the one surface of the light guide plate of 45 degrees or more and 60 degrees or less.   The display device according to claim 1, wherein the concave portion has a substantially rectangular shape in a plan view, and an aspect ratio thereof ranges from 10: 1 to 1: 1.   8. The display device according to claim 1, wherein, of the plurality of recesses, at least a part of the reflection surfaces of the recesses are formed in a flat shape.   The display device according to claim 1, wherein the light source is formed to extend along an extending direction of the light guide plate.   The display device according to claim 9, wherein the light source includes a plurality of light emitting diodes arranged in a predetermined direction.

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