JP2008275921A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device which represents light beams of different light sources on one plane and expresses an elaborate design. <P>SOLUTION: A display device 10 includes a plurality of light sources 4 and a light guide plate 1 having a plurality of recessed parts 2 having reflecting surfaces which reflect a light beam from one of the plurality of light sources 4. The recessed parts 2 are formed in such positions as to reflect a light beam incident from a light source 4, toward a display surface 1b by reflecting surfaces 2a of the recessed parts 2 according to the position of the light source 4 whose light beam is made incident on the recessed part 2. <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.

  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.

A display device having a display unit in which LED elements are provided in a predetermined arrangement between two transparent glass plates is also used (see, for example, Patent Document 1).
European Patent No. 099199

  In the display device having the roughened display portion, light is scattered by the display portion, so that the luminance per unit area of the display portion is lowered and the visibility becomes insufficient. In order to improve visibility, it is necessary to increase the area of the display portion.

  However, if the area of the display portion which is an opaque portion is large, the background cannot be seen through, and the transparency which is a characteristic of this display device is lost, and its value is diminished.

  In the display device in which the LED element is provided between the transparent glass plates, the transmitted light is blocked only by the LED element, so that the transparency is good. However, the electrode wiring pattern is complicated, so that it is difficult to manufacture and is very expensive. .

  In addition, unlike a display device in which the light source and the light guide plate are separate bodies, it is necessary to replace the entire light source (LED element) including the light source in order to change the design of the display unit.

  The present invention has been made in view of the above circumstances, and provides a display device that is excellent in transparency, easily visible in a display unit, easily manufactured at low cost, and capable of expressing a complicated design. For the purpose.

  In order to achieve the above object, a display device according to a feature of the present invention includes a plurality of light sources and a plurality of recesses having a reflection surface that reflects light from any one of the plurality of light sources to the display surface side of the image. And a concave portion in a position and a direction corresponding to the position of the light source incident on the concave portion so that the light incident from the light source can be reflected to the display surface side by the reflective surface of the concave portion. It is formed.

  The light source is preferably formed on at least one of a display surface of the light guide plate and a surface different from the surface facing the display surface.

  It is preferable that the concave portion is arranged so that any one or more combinations of characters, symbols, figures, and patterns are displayed on the display surface.

  The plurality of light sources preferably emit light of any color. At this time, one or more combinations of characters, symbols, figures, and patterns may be displayed on the display surface in a plurality of colors emitted from a plurality of light sources. Further, one or more combinations of characters, symbols, figures, and patterns may be displayed on the display surface with a predetermined color emitted from a plurality of light sources.

  A plurality of recesses that reflect light emitted from different light sources may be formed adjacent to each other.

  It is preferable that the concave portion is formed by a dot-shaped notch formed in the light guide plate. Here, it is preferable that the reflection surface of the recess has an angle with respect to the surface on which the light source is formed of 45 degrees or more and 60 degrees or less. Moreover, it is preferable that a recessed part is made into the substantially rectangular shape in planar view, and the aspect ratio is the range from 10: 1 to 1: 1.

  The light source is preferably formed so as to extend along the extending direction of the light guide plate. or. The light source may include a plurality of light emitting diodes arranged in a predetermined direction.

  The display device of the present invention is excellent in transparency, the display portion is easily visible, can be easily manufactured at low cost, and can express a more complicated design.

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

  As shown in FIGS. 1 and 2, a display device 10 according to the best mode of the present invention is provided on a transparent light guide plate 1 having parallel planes and end faces 1 a and 1 d of the light guide plate 1, and directed toward the light guide plate 1. A plurality of light sources 4a and 4b that emit light. The display device 10 according to the best mode of the present invention can express a plurality of designs or multicolor designs with a single light guide plate.

  First, the light sources 4a and 4b will be described. The light source 4 a and the light source 4 b emit light that causes the light guide plate 1 to display an image through reflection by the dot-like reflection part (concave part) 2. The light sources 4a and 4b are formed on any one of a plurality of surfaces of the light guide plate 1 and a surface different from the display surface 1b of the light guide plate 1 and the back surface 1c facing the display surface.

  As the light source 4a and the light source 4b, an LED, an LD (laser diode), or the like can be used. The light source 4 a and the light source 4 b are 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 source 4 a is formed to extend along the end surface 1 a on one side of the substantially rectangular light guide plate 1. On the other hand, the light source 4b is formed to extend along an end face 1d on one side of the light guide plate 1 having a substantially rectangular shape.

  As the light source 4a, for example, a plurality of LEDs arranged in a direction along the end face 1d can be used. Similarly to the light source 4a, for example, a light source 4b in which a plurality of LEDs are arranged in a direction along the end face 1a can be used. The color of the light emitted from the light source 4a and the light source 4b can be any color such as white, red, green, and blue, and can be selected as appropriate according to the pattern formed by the dot-like reflection unit 2. The light source 4a and the light source 4b may emit light of the same color or may emit light of different colors. The light source 4a and the light source 4b can also be provided on one and the other end surfaces of the light guide plate 1.

  Next, the light guide plate 1 will be described. 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 dot-like reflecting portion 2 has such a light transmittance that it can be visually recognized. This definition is commonly used in the present invention.

  As shown in FIGS. 3 and 4, a display unit 3 including a plurality of dot-like reflection units 2 is formed on the back surface 1 c of the light guide plate 1. As shown in FIG. 2, the dot-like reflecting portion 2 is a notch formed in the back surface 1 c.

  Next, the dot-shaped reflection part 2 is demonstrated. In the example shown in FIG. 1 to FIG. 4, the display device 10 according to the best embodiment of the present invention is a reflective surface that reflects the light from the light source 4 a toward the display surface 1 b of the image as the dot-like reflection unit 2. Dot-like reflecting portions 21a, 21b, and 21c, and dot-like reflecting portions 22a, 22b, 22c, and 22d having reflecting surfaces that reflect light from the light source 4b toward the image display surface 1b. The dot-like reflecting portion 2 corresponds to the position of the light source 4 incident on the dot-like reflecting portion 2, and is a position where the light incident from the light source 4 can be reflected to the display surface 1b side by the reflecting surface 2a of the dot-like reflecting portion 2. And in the direction. The dot-like reflecting portions 21a, 21b, and 21c and the dot-like reflecting portions 22a, 22b, 22c, and 22d have the same configuration except that the light source of the reflected light is different.

  The dot-like reflecting portion 21a is shaped such that light from the light source 4a strikes the reflecting surface 2a. In the present embodiment, the dot-like reflecting section 2 has a substantially rectangular shape in plan view (see FIG. 6) and has a cross section that is a triangle having the reflecting surface 2a as a hypotenuse (see FIG. 5).

  The dot-shaped reflection part 21a may be any structure as long as it is formed in the light guide plate 1 and reflects the light from the light source 4a toward the surface 1b, and the configuration is not limited to the illustrated example. For example, it may be a notch having a cross-sectional shape such as a quadrilateral or more polygon (for example, trapezoid) or a sector. Moreover, the through-hole formed in the light-guide plate 1 may be sufficient, and the space part formed in the light-guide plate 1 may be sufficient. The dot-like reflection parts 21b and 21c also have the same configuration as the dot-like reflection part 21a.

  The dot-like reflecting portion 22a may be formed in the light guide plate 1 and reflect the light from the light source 4b toward the surface 1b, and the configuration is not limited to the illustrated example. For example, it may be a notch having a cross-sectional shape such as a quadrilateral or more polygon (for example, trapezoid) or a sector. Moreover, the through-hole formed in the light-guide plate 1 may be sufficient, and the space part formed in the light-guide plate 1 may be sufficient. The dot-like reflecting portions 22b, 22c and 22d also have the same configuration as the dot-like reflecting portion 22a.

  The aspect ratio (aspect ratio) (average value) of the dot-like reflecting portions 2 when viewed in plan is preferably in the range of 10: 1 to 1: 1, and preferably in the range of 5: 1 to 1: 1. Is more preferable.

  As shown in FIG. 6, 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 dot-like reflecting portion 2 shown in FIGS. 5 and 6, and β2 is the upper side 2c orthogonal to the light incident direction and This is the length of the lower side 2d.

  If the length β1 with respect to the length β2 is too large, the shape of the light from the dot-like reflecting portion 2 becomes close to a linear shape, which is not preferable because the transparency characteristic of the display device 10 is impaired. If the length β1 with respect to the length β2 is too small, the luminance of the dot-like reflecting portion 2 becomes 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 smallest area that is inscribed by the dot-like reflecting portion 2 in plan view.

  In addition, the planar view shape of the dot-shaped reflection part 2 is not limited to the illustrated example, and may be a polygon such as a triangle or a pentagon, a circle, or an ellipse.

  If the inclination angle (angle α shown in FIG. 5) of the reflection surface 2a with respect to the back surface 1c of the light guide plate 1 is too small, the inclination angle of the emitted light also increases, and the dot-like reflection portion 2 when the display device 10 is viewed from the front. Visibility is reduced. 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 perpendicular to the surface 1b, so that the visibility of the dot-like reflecting portion 2 can be enhanced.

  In the illustrated example, the reflecting surface 2a is flat, but at least a part of the reflecting surface may be curved. If the reflection surface is a curved surface, the emission angle of the reflected light may extend over a wide range. In this case, the dot-like reflection unit 2 can be viewed from a wide range.

  The surface roughness (maximum height Ry) of the reflecting surface 2a (JIS B 0601-1994) is preferably a smooth flat surface in order to increase the light reflection efficiency on the reflecting surface 2a.

  If the height of the dot-like reflecting portion 2 (height γ shown in FIG. 5) is too small, the visibility of the dot-like reflecting portion 2 is lowered, and if it is too large, the transparency of the display device 10 is not preferable. The average value of the height γ of the dot-like reflecting portion 2 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 dot-like reflecting portion 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.

  In the dot-like reflecting portion 2, the brightness of the reflected light from the dot-like reflecting portion 2 is set according to the planar view area (β1 × β2) of the reflecting surface 2a. The planar view area of the reflecting surface 2a is adjusted by changing the height γ of the dot-like reflecting portion 2, the length β2 of the upper side 2c (lower side 2d), and the like, whereby the luminance of the reflected light of the dot-like reflecting portion 2 is adjusted. Adjusted.

  In the illustrated example, the display unit 3 is arranged so that a plurality of dot-like reflection units 2 form a predetermined pattern. The display unit 3 displays one or more combinations of characters, symbols, figures, and patterns.

  “The dot-like reflecting portion 2 forms a predetermined pattern” means that the dot-like reflecting portion 2 has a densely arranged portion and a sparsely arranged portion. It means that it is arranged uniformly.

  In the example shown in FIGS. 1 to 4, for each light source 4a or 4b, the dot-like reflecting portion 2 may be arranged so that the dot-like reflecting portion 2 that reflects light emitted from the light source forms a predetermined pattern. . In this case, a combination of one or more of characters, symbols, figures, and patterns is displayed on the end surface 1 b of the light guide plate 1 in a predetermined color emitted from the plurality of light sources 4 a and 4 b. Here, since characters, symbols, figures, patterns, etc. are displayed on the display unit 3 for each predetermined color, different images can be obtained by turning on one of the light sources 4a and 4b and turning off one of them. It can be displayed on the display device 1.

  In addition, the dot-like reflecting portion 2 may be arranged in the display portion 3 so that the dot-like reflecting portion 2 that reflects light emitted from the light sources 4a and 4b forms a predetermined pattern. In this case, a combination of one or more of letters, symbols, figures, and patterns is displayed on the end surface 1 b of the light guide plate 1 in a plurality of colors emitted from the plurality of light sources 4 a and 4 b. Here, by turning on all the light sources 4a and 4b, images of a plurality of colors can be displayed on the display device 1.

  In the display device 10, the front surface 1 b side (or the back surface 1 c side) of the light guide plate 1 is not provided with a configuration (for example, a light diffusing plate) that impairs the transparency of the display device 10. Is visible as a dot-like bright spot.

  A semitransparent layer may be provided on the front surface 1b side (or the back surface 1c side) of the light guide plate 1 as long as the dot-like reflecting portion 2 is observed as a dot-like bright spot.

  As shown in FIG. 5, in the display device 10, light from the light source 4 a or the light source 4 b is incident on the light guide plate 1 from the end surface 1 a, reflected on the reflecting surface 2 a of the dot-like reflecting portion 2, and emitted from the surface 1 b side. be able to. When viewed from the front surface 1b side, the dot-like reflecting portion 2 is observed as a dot-like bright spot.

  The light from the light source 4a or the light source 4b is reflected at a high reflectance on the reflecting surface 2a and the reflecting surface 5a and travels in a substantially constant direction (in the illustrated example, a direction perpendicular to the surface 1b). The brightness of is sufficiently large. For this reason, even when observing at a distance, excellent visibility is obtained.

  In the display device 10 according to the best embodiment of the present invention, one light guide plate 1 is emitted from the second light source 4b and the dot-like reflection part 21a that reflects the light emitted from the first light source 4a. And a dot-like reflecting portion 22a that reflects light. Therefore, in the display device 10 according to the preferred embodiment of the present invention, a plurality of designs can be expressed with a plurality of colors.

  On the other hand, in order to express a plurality of designs with a plurality of colors, for example, as shown in FIGS. 16 and 17, a dot-like reflection that reflects light emitted from the first light source 4 a to the first light guide plate 110. There is a method in which the portion 2 is provided, and the second light guide plate 120 is provided with the dot-like reflection portion 2 that reflects the light emitted from the second light source 4b. However, according to the display device 10 shown in FIGS. 16 and 17, since a plurality of light guide plates are used, there is a problem that the cost is increased and the thickness of the display device 10 is increased. Therefore, the display device 10 according to the preferred embodiment of the present invention described with reference to FIGS. 1 to 4 is reduced in cost, size, weight, and the like as compared with the display device shown in FIGS. It has the effect of.

  As described above, since a complicated design can be easily realized, it is possible to produce a healing space by introducing the display device of this embodiment into various places. For example, by installing the display device of the present embodiment in amusement facility walls, automatic doors, elevator rooms, system kitchens, bathrooms, toilets, automobiles, airplanes, and other transport equipment, it is possible to produce healing effects in these spaces. It can be carried out.

  In the display device 10, since the dot-like reflecting portion 2 is dot-like, the area is small, and the transparency of the display device 10 is not impaired. 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.

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

  In order to manufacture the display device 10 according to the best embodiment of the present invention, as shown in FIG. 7, first, for each of the dot-like reflecting portions 21a, 21b, and 21c that reflect the light from the light source 4a, In step S <b> 101, dot-like reflecting portions 21 a, 21 b and 21 c are formed on the light guide plate 1.

  Next, in step S102, the light guide plate is rotated in the extending direction. At this time, you may rotate the processing tool 13 mentioned later.

  Finally, for each of the dot-like reflecting portions 22a, 22b, 22c, and 22d that reflect the light from the step light source 4b, the dot-like reflecting portions 22a, 22b, 22c, and 22d are formed on the light guide plate 1 in S103.

  Next, with reference to FIG. 8 to FIG. 10, a procedure for forming the dot-like reflecting portion 2 in Step S <b> 101 and Step S <b> 103 of FIG. 7 will be described.

  In the formation of the dot-like reflecting part 2, as shown in FIG. 8, a processing tool 13 having a blade part 12 protruding from the lower surface of the base part 11 is used. The blade portion 12 has a shape corresponding to the dot-like reflecting portion 2, and the vertex angle (vertex angle δ shown in FIG. 8) 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. 9 and 10, 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 dot-like reflection portion 2 can be easily formed.

  As a result, a dot-like reflecting portion 2 having a shape along the blade portion 12 is formed on the back surface 1 c of the light guide plate 1.

  Further, the processing tool 13 is moved horizontally, and the same operation is repeated to form the dot-like reflection portions 21a, 21b and 21c. After the light guide plate 1 is rotated, the same operation is repeated to form the dot-like reflecting portions 22a, 22b, 22c and 22d. In this way, the display unit 3 composed of a plurality of dot-like reflection units 2 is formed, and the display device 10 shown in FIGS. 1 to 4 is obtained.

  According to the manufacturing method using the processing tool 13, the dot-shaped reflection part 2 of an exact 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 dot-like reflecting portion 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.

(First modification)
A display device 10 according to a first modification of the preferred embodiment of the present invention will be described with reference to FIGS.

  The display device 10 according to the first modification is different from the best embodiment of the present invention described with reference to FIGS. 1 to 4 in that a light source 4c and a light source 4d are provided. Accordingly, dot-shaped reflecting portions 23a, 23b, and 23c that reflect the light emitted from the light source 4c and 24a and 24b that reflect the light emitted from the light source 4d are different.

  The light source 4 c is provided on the surface 1 e that faces the end surface 1 a of the light guide plate 1. The dot-like reflecting portions 23a, 23b, and 23c have a reflecting surface that can reflect the light emitted from the light source 4c. The light source 4 d is provided on a surface 1 f that faces the end surface 1 d of the light guide plate 1. The dot-like reflection parts 24a and 24b have reflection surfaces that can reflect the light emitted from the light source 4d.

  According to such a display apparatus 10, since it has four light sources, the design expressed with four colors can be expressed. Moreover, four types of designs can be expressed by emitting light from any of the four light sources.

(Second modification)
With reference to FIGS. 14 and 15, a display device 10 according to a second modification of the preferred embodiment of the present invention will be described.

  The display device 10 according to the second modified example has a plurality of dot-like reflecting portions 2 that reflect light emitted from different light sources, as compared with the best embodiment of the present invention described with reference to FIGS. However, they are different in that they are formed adjacent to each other. More specifically, in the example shown in FIG. 14, a dot-like reflecting portion 21a that reflects the light emitted from the first light source 4a, and a dot-like reflecting portion 23a that reflects the light emitted from the second light source 4c; Are formed adjacent to each other.

  According to the display device 10 according to the second modification as described above, a large bright spot can be formed by making the colors of the light emitted from the first light source 4a and the second light source 4c the same. Further, by making the colors of the light emitted from the first light source 4a and the second light source 4c different, light with a plurality of colors mixed can be displayed on the display surface 3, and a complicated design can be displayed. Accordingly, red light can be emitted from one light source and blue light can be emitted from the other light source, so that purple light can be emitted from two adjacent dot reflection portions.

(Other embodiments)
As described above, the best embodiment of the present invention, the first modified example, and the second modified example have been described. However, the description and drawings constituting a part of this disclosure are intended to limit the present invention. Should not be understood. From this disclosure, various alternative embodiments, examples, and operational techniques will be apparent to those skilled in the art.

  It goes without saying that the present invention includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

FIG. 1 is a perspective view schematically showing a display device according to the best embodiment of the present invention. FIG. 2 is a plan view of the display device shown in FIG. FIG. 3 is a cross-sectional view of the display device shown in FIG. 2 taken along A-A ′. 4 is a cross-sectional view of the display device shown in FIG. 2 taken along the line B-B ′. FIG. 5 is an enlarged cross-sectional view of a main part of the display device shown in FIG. FIG. 6 is a plan view of the dot-like reflecting portion of the display device shown in FIG. FIG. 7 is a flowchart showing a method of manufacturing the display device shown in FIG. FIG. 8 is a process diagram showing a method of manufacturing the display device shown in FIG. FIG. 9 is a process diagram following FIG. FIG. 10 is a process diagram following FIG. FIG. 11 is a plan view of a display device shown in a first modification of the best mode for carrying out the invention. FIG. 12 is a cross-sectional view of the display device shown in FIG. 11 taken along A-A ′. 13 is a cross-sectional view of the display device shown in FIG. 11 taken along the line B-B ′. FIG. 14 is a plan view of a display device shown in a second modification of the best mode for carrying out the invention. 15 is a cross-sectional view of the display device shown in FIG. 14 cut along A-A ′. FIG. 16 is a perspective view schematically showing a display device having a plurality of light guide plates. 17 is a cross-sectional view of the display device shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light guide plate 2, 21, 22, 23, 24 Dot-shaped reflection part 2a Reflecting surface 3 Display part 4, 4a, 4b Light source 10 Display apparatus 11 Base 12 Blade part 13 Processing tool

Claims (12)

Multiple light sources;
A light guide plate formed with a plurality of recesses having a reflection surface that reflects light from any one of the plurality of light sources to the display surface side of the image,
The concave portion is formed in a position and a direction corresponding to the position of the light source incident on the concave portion so that the light incident from the light source can be reflected to the display surface side by the reflective surface of the concave portion. Display device.   The display device according to claim 1, wherein the light source is formed on at least one of the display surface of the light guide plate and a surface different from the surface facing the display surface.   The display device according to claim 1, wherein the concave portion is arranged so that any one or more of a character, a symbol, a figure, and a pattern is displayed on the display surface.   The display device according to claim 1, wherein the plurality of light sources emit light of an arbitrary color.   The display device according to claim 4, wherein a combination of one or more of a character, a symbol, a figure, and a pattern is displayed on the display surface in a plurality of colors emitted from the plurality of light sources.   The display device according to claim 4, wherein a combination of one or more of a character, a symbol, a figure, and a pattern is displayed on the display surface in a predetermined color emitted from the plurality of light sources. .   The display device according to claim 1, wherein a plurality of concave portions that reflect light emitted from different light sources are formed adjacent to each other.   The display device according to claim 1, wherein the concave portion includes a dot-shaped notch formed in the light guide plate.   The display device according to claim 1, wherein an angle of the reflective surface of the concave portion with respect to a surface on which the light source is formed is 45 degrees or more and 60 degrees or less.   10. 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.   The display device according to claim 1, wherein the light source is formed so as to extend along an extending direction of the light guide plate.   The display device according to claim 11, wherein the light source includes a plurality of light emitting diodes arranged in a predetermined direction.

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