JP4881786B2 - Display device - Google Patents

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, Patent Document 1 discloses a display device having a display unit in which LED elements are provided in a predetermined arrangement between two transparent glass plates.
European Patent No. 099199

  In a display device in which an LED directly emits light as disclosed in Patent Document 1, it is basically installed near a power supply, or at least electrical wiring is arranged near the LED. In this case, an electric shock or a short circuit may occur due to the influence of water or dust, and the display portion of the display device may be greatly damaged. In addition, when the display device is installed at a high place, maintenance may be difficult.

  The present invention has been made in view of the above, and an object of the present invention is to provide a display device that can prevent a failure due to an electric shock or a short circuit of a display portion and that can be easily maintained.

In order to achieve the above object, a display device of the present invention receives a plurality of light emitting diodes that emit light and light from the plurality of light emitting diodes on one side, and transmits light incident on the one side. A plate-like optical transmission unit that emits light from the other side surface, and a side surface disposed opposite to the other side surface of the optical transmission unit as an incident side surface, and light from the light transmission unit incident from the incident side surface And a light guide plate having a plurality of recesses formed on the other surface side, and the light guide plate as a display portion is installed in an environment affected by water and dust. The plurality of light emitting diodes are arranged in the vicinity of the power source and are arranged along the one side surface of the light transmission unit, and the recesses formed in the light guide plate include characters, symbols, figures, patterns. A combination of any one or more of And the width and height of the other side surface of the light transmission unit are smaller than the width and height of the incident side surface of the light guide plate, respectively, and the other side of the light transmission unit The entire side surface faces the incident side surface of the light guide plate .

  In addition, the reflection surface of the recess formed in the light guide plate according to the display device of the present invention has an angle with respect to the other surface of the light guide plate of 45 degrees or more and 60 degrees or less.

  In addition, the concave portion formed in the light guide plate according to the display device of the present invention has a substantially rectangular shape in plan view, and an aspect ratio thereof ranges from 10: 1 to 1: 1.

  In addition, among the plurality of recesses formed in the light guide plate according to the display device of the present invention, at least a part of the reflection surfaces of the recesses are formed in a planar shape.

  In the display device of the present invention, the light from the light source is transmitted by the light transmission unit and is incident on the light guide plate. Therefore, the light guide plate constituting the display portion is electrically neutral and is due to an electric shock or a short circuit of the display portion. Failure can be prevented. Further, since the light source can be set apart from the light guide plate, maintenance can be easily performed.

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

(First embodiment)
1 is a perspective view schematically showing a display device according to a first 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 view of a main part of the display device shown in FIG. Sectional drawing and FIG. 4 are top views of the recessed part of the display apparatus shown in FIG.

  As shown in FIGS. 1 and 2, the display device 10 according to the first embodiment includes a transparent light guide plate 1, a light source 4, and a light transmission plate 5 that transmits light from the light source 4.

  As the light source 4, an LED, an LD (laser diode), or the like can be used. The light source 4 is formed to extend along the side surface 5 a on one side of the substantially rectangular light transmission plate 5, and emits light toward the light transmission plate 5.

  As the light source 4, for example, a plurality of LEDs arranged in a direction along the side surface 5a of the light transmission plate 5 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 concave portion 2 of the light guide plate 1.

  The light transmission plate 5 is made of a light-transmitting material, for example, acrylic resin, quartz glass, or multicomponent glass. The light transmission plate 5 transmits light from the light source 4 incident from the side surface 5a and emits light from the side surface 5b facing the side surface 5a. The light transmission plate 5 is disposed such that the side surface 5b, which is the light emission surface, faces the side surface 1a on one side of the substantially rectangular light guide plate 1, and light emitted from the side surface 5b of the light transmission plate 5 is transmitted. The light guide plate 1 enters the light guide plate 1 from the side surface 1a. The optical transmission plate 5 is not limited to a planar shape as in the illustrated example, but may be a curved surface.

  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 silicon 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.

  On the back surface 1 c of the light guide plate 1, a display unit 3 including a plurality of recesses 2 is formed. The recess 2 has a reflecting surface 2a that reflects light from the light source 4 transmitted by the light transmission plate 5 and incident from the side surface 1a to the surface 1b side. The recess 2 is shaped so that incident light 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, the surface of the reflection surface 2a is preferably a smooth flat surface.

  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.

  In the display device 10, light from the light source 4 is transmitted by the light transmission plate 5, and light emitted from the side surface 5 b of the light transmission plate 5 enters the light guide plate 1 from the side surface 1 a that is the incident side surface of the light guide plate 1. Let And as shown in FIG. 3, the light which injected in the light-guide plate 1 is reflected in the reflective surface 2a of the recessed part 2, and is radiate | emitted from the surface 1b 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 transmitted by the light transmission plate 5 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). The brightness of 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.

  Further, since the light guide plate 1 and the light transmission plate 5 constituting the display portion are electrically neutral, it is possible to prevent a failure due to an electric shock or a short circuit of the display portion. Further, since the light source 4 can be installed away from the light guide plate 1, even when the light guide plate 1 is installed at a high place, the light source 4 can be installed at hand to easily perform maintenance.

  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.

  As shown in FIG. 8, protective plates 6 and 7 can be provided on the front surface 1b of the light guide plate 1 and the back surface 1c of the light guide plate 1, respectively. The material of the protective plates 6 and 7 may be a transparent material, and synthetic resins such as acrylic resin and polycarbonate resin, and glass are suitable. The protection plates 6 and 7 can enhance the durability of the display device.

(Second Embodiment)
FIG. 9 is a perspective view schematically showing a display device according to the second embodiment of the present invention, and FIG. 10 is a plan view of the display device shown in FIG. In addition, about the structure similar to the structure of the display apparatus which concerns on 1st Embodiment shown in FIG. 1 among the structures of the display apparatus which concerns on 2nd Embodiment shown in FIG. 9, FIG. 10, the same code | symbol is used. Detailed description will be omitted.

  As shown in FIGS. 9 and 10, the display device 20 according to the second embodiment omits the light source 4 and the light transmission plate 5 from the display device 10 shown in FIG. In this configuration, an optical transmission body 22 and a rod-shaped light guide body 23 are added.

  As the light source 21, an LED, an LD, or the like can be used. The rod-shaped optical transmission body 22 is made of a light-transmitting material, such as acrylic resin, quartz glass, or multicomponent glass. One end surface of the optical transmission body 22 is optically coupled to the light source 21, and light incident from one end surface (incident surface) is emitted from the other end surface (exit surface).

  The light guide 23 is made of the same material as that of the light guide plate 1, for example, acrylic resin, and has a rectangular cross-sectional shape and a rod shape. The light exiting surface of the light transmission body 22 is connected to one end face 23a in the length direction of the light guide 23, and the light from the light source 21 transmitted by the light transmission body 22 enters the light guide 23 from the end face 23a. Incident.

  The light guide 23 is disposed so that one side surface 23 b faces the side surface 1 a that is the incident side surface of the light guide plate 1. A plurality of recesses 2 having the same configuration as that formed on the light guide plate 1 are formed on the side surface 23c of the light guide 23 opposite to the side surface 23b at intervals in the length direction of the light guide 23. Yes. The recess 2 reflects incident light to the side surface 23b side by the reflecting surface 2a.

  In the display device 20, the light from the light source 21 is transmitted by the light transmission body 22, and the transmitted light enters the light guide 23 from the end face 23 a of the light guide 23. The light that has entered the light guide 23 is reflected by the reflecting surface 2 a of the recess 2 of the light guide 23 and is emitted from the side surface 23 b of the light guide 23. The light emitted from the side surface 23 b side of the light guide 23 enters the light guide plate 1 from the side surface 1 a that is the incident side surface of the light guide plate 1.

  As in the first embodiment, the light incident on the light guide plate 1 is reflected by the reflecting surface 2a of the recess 2 and is emitted from the surface 1b side. When viewed from the surface 1b side, the recess 2 is observed as a dot-like bright spot.

  Even in this case, the light guide plate 1, the light transmission body 22, and the rod-shaped light guide body 23 that constitute the display portion are electrically neutral, and therefore, the display portion can be prevented from being damaged due to an electric shock or a short circuit. Can do. Further, since the light source 21 can be installed away from the light guide plate 1, even when the light guide plate 1 is installed at a high place, the light source 21 can be installed at hand to easily perform maintenance.

  In addition, you may comprise the optical transmission body 22 with an optical fiber. Moreover, you may comprise the recessed part formed in the light guide 23 so that it may cross over the full width of the side surface 23c.

1 is a perspective view schematically showing a display device according to a first 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 which provided the protective plate. It is a perspective view which shows typically the display apparatus which concerns on the 2nd Embodiment of this invention. It is a top view of the display apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light guide plate 2 Recessed part 2a Reflecting surface 3 Display part 4,21 Light source 5 Optical transmission board 6,7 Protection board 10,20 Display apparatus 22 Optical transmission body 23 Light guide

Claims (4)

A plurality of light emitting diodes that emit light ;
A plate-shaped light transmission unit that receives light from the plurality of light emitting diodes on one side surface, transmits light incident from the one side surface, and emits light from the other side surface;
A plurality of recesses having a reflection surface for reflecting light from the light transmission unit incident from the incident side surface to one surface side is defined as a side surface disposed opposite to the other side surface of the light transmission unit. A light guide plate formed on the direction side ,
The light guide plate as a display part is installed in an environment affected by water and dust,
The plurality of light emitting diodes are disposed in the vicinity of the power source, and are arranged along the one side surface of the light transmission unit,
The recesses formed in the light guide plate are arranged to display any one or more combinations of characters, symbols, figures, patterns,
The width and height of the other side surface of the light transmission unit are smaller than the width and height of the incident side surface of the light guide plate, respectively, and the entire other side surface of the light transmission unit is A display device characterized by facing the incident side surface. The display device according to claim 1, wherein an angle of the reflection surface of the concave portion formed in the light guide plate with respect to the other surface of the light guide plate is 45 degrees or more and 60 degrees or less. 3. The display device according to claim 1, wherein the concave portion formed in the light guide plate has a substantially rectangular shape in a plan view, and an aspect ratio thereof ranges from 10: 1 to 1: 1. . Among the plurality of recesses formed in the light guide plate, at least a reflective surface of a portion of the recess according to any one of claims 1 to 3, characterized in that part is formed in a planar shape Display device.

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