JP2008299079A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device capable of preventing occurrence of undesired reflection and improving appearance of display with a simple device constitution. <P>SOLUTION: The display device includes: a transparent light guide plate 1; a light source 4 disposed along the end face 1a of the light guide plate 1; a plurality of recessed parts 2 disposed in the light guide plate 1, each having a reflection surface to reflect light emitted from the light source 4 and made incident on the end face 1a of the light guide plate 1 toward the image display surface side of the light guide plate 1; protecting plates 25 and 26 disposed at least either of the image display surface side or the opposite surface side of the light guide plate 1; and anti-reflection films 27 to 32 disposed on at least any of the image display surface of the light guide plate 1, the opposite surface of the light guide plate 1, the front surface of the protecting plate 1 and the rear surface of the protecting plate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a display device used for a display or the like, and more particularly to a fixing structure between a side-emitting light emitting element and a light guide plate.

  2. Description of the Related Art Conventionally, a display device that is used for a display or the like by displaying an image such as a character, a figure, or a pattern using a point light source such as a light emitting diode or an organic EL element is known. For example, Patent Document 1 discloses a display device that displays a desired image by arranging a plurality of light emitting diodes between two transparent glass plates. In such a display device, light emitting diodes are required for the number of dots, and wiring is also required in accordance with the number of light emitting diodes, resulting in a problem that the configuration becomes very complicated and expensive.

  Therefore, in order to simplify the configuration, a display device that displays an image by arranging a light emitting diode or the like only on an end face of a light guide plate that can transmit light and reflecting a part of the light guided through the light guide plate. Are known.

  For example, as the above-described display device, a configuration is known in which a plurality of recesses are formed on one surface of a light guide plate by laser processing, and light is reflected by the surface of the recesses to display an image. However, in order to form a plurality of recesses surrounded by a curved surface by laser processing in the light guide plate, the light guide plate has to be thickened, which makes it difficult to reduce the thickness of the display device.

  Therefore, in recent years, display devices have been made thinner by thinning the light guide plate by a manufacturing method other than laser processing. However, when the light guide plate is configured to be thin, there is a problem that scratches formed on the display surface of the light guide plate and attached dirt are conspicuous. In order to suppress the formation of scratches on the light guide plate, a configuration in which the display surface and the back surface of the light guide plate are protected by a pair of protection plates has been proposed.

In addition, since the light guide plate can be configured to be thin, attempts have been made to enable three-dimensional display by using a plurality of light guide plates in an overlapping manner.
European Patent No. 099199

  However, in a structure in which protective plates are stacked on top and bottom with a light guide plate in between or a plurality of light guide plates are stacked, the light emitted from the light-emitting element that is a light source is reflected by the protective plate and the light guide plate, and unnecessary reflection occurs. There was a problem of obstructing the appearance of the display.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a display device that can improve the appearance of a display by preventing the occurrence of unnecessary reflections with a simple device configuration.

  In order to achieve the above object, a display device according to the present invention includes a transparent light guide plate, a light source provided along an end surface of the light guide plate, and provided on the light guide plate and incident from the end surface of the light guide plate. A plurality of recesses having a reflection surface for reflecting the light from the light source to the image display surface side of the light guide plate, and a protection plate provided on at least one of the image display surface side and the opposite surface side of the light guide plate And an anti-reflection film provided on at least one of the image display surface of the light guide plate, the opposite surface of the light guide plate, the front surface of the protection plate, or the back surface of the protection plate. .

  A display device according to another invention includes an image display unit formed by laminating a plurality of transparent light guide plates, a light source provided along each end face of the laminated light guide plates, and each of the light guides. A plurality of recesses having a reflection surface provided on the light plate and reflecting light from the light source incident from the end surface of the light guide plate to the image display surface side of the light guide plate; and a front side or a back side of the image display unit A protective plate provided on at least one of the above, and an image display surface of each light guide plate, an opposite surface of each light guide plate, a surface of the protective plate, or a back surface of the protective plate. And an antireflection film.

  According to the present invention, it is possible to improve the appearance of the display by preventing the occurrence of unnecessary reflection with a simple configuration.

<Basic configuration>
Prior to the description of the embodiments, first, the basic configuration of the display device according to the present invention will be described.

  1 is a perspective view schematically showing a display device according to the present invention, FIG. 2 is a cross-sectional view of the display device shown in FIG. 1, FIG. 3 is an enlarged cross-sectional view of the main part of the display device shown in FIG. FIG. 2 is a plan view of a dot-like reflecting portion of the display device shown in FIG.

  As shown in FIGS. 1 and 2, the display device 10 includes a transparent light guide plate 1 having parallel planes, 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. .

  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 dot-like reflection unit 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 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.

  On the back surface 1 c of the light guide plate 1, a display unit 3 including a plurality of dot-like reflection units 2 is formed. As shown in FIG. 2, the dot-like reflecting portion 2 is a notch formed in the back surface 1c, and reflects light that is emitted from the light source 4 and incident from the end surface 1a to the front surface (image display surface) 1b side. It has surface 2a. The dot-like reflecting portion 2 is shaped so that the light from the light source 4 strikes the reflecting surface 2a. For example, the dot-like reflecting portion 2 has a substantially rectangular shape in plan view (see FIG. 4), and has a cross section that is a triangle having the reflecting surface 2a as a hypotenuse (see FIG. 3).

  The dot-like reflection part may be any structure that is formed in the light guide plate 1 and reflects the light from the light source 4 toward the surface (image display 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.

  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. 3) 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 reflecting surface 2a is preferably a smooth flat surface.

  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.

  If the area of all the dot-like reflecting portions 2 is constant, the intensity of the reflected light at the dot-like reflecting portion 2 located far from the light source 6 tends to be lower than the reflected light at the dot-like reflecting portion 2 close to the light source 6. There is.

  For this reason, it is preferable to make the intensity of the reflected light of the dot-like reflection part 2 uniform by increasing the area of the dot-like reflection part 2 according to the distance from the light source 6.

  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 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 FIG. 1, it has the part 4a where the dot-shaped reflection part 2 is arrange | positioned densely, and the part 4b arrange | positioned sparsely. The densely arranged portion 4a includes five linear array portions 5a to 5e in which a plurality of dot-like reflecting portions 2 are arrayed in a certain direction.

  It is preferable to arrange the dot-like reflecting portions 2 so as to form letters, symbols, figures, patterns, or a combination of two or more of these.

  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. 3, in the display device 10, the light from the light source 6 can be 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. . When viewed from the front surface 1b side, the dot-like reflecting portion 2 is observed as a dot-like bright spot.

  Most of the light from the light source 6 is reflected by the reflecting surface 2a and travels in a substantially constant direction (in the illustrated example, a direction perpendicular to the surface 1b), so that the intensity of the light is sufficiently increased. For this reason, even when observing at a distance, excellent visibility is obtained.

  Since the dot-like reflecting portions 2 are arranged so as to form a predetermined pattern, this pattern can be visually recognized by observing from the surface 1b side.

  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.

  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 dot-like reflecting portion 2, and the vertex angle (vertex 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 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.

  By moving the processing tool 13 horizontally and repeating the same operation, the display unit 3 including a plurality of dot-like reflection units 2 is formed, and the display device 10 shown in FIGS. 1 to 4 is obtained. In addition, when forming the dot-shaped reflection part 2 from which brightness | luminance differs, it replaces | exchanges for the processing tool 13 provided with the blade part 12 of a different size, and performs the same operation as the above.

  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.

<Description of Embodiment>
Next, a preferred embodiment of a display device having the basic configuration described above will be described with reference to FIGS.

  FIG. 8 is a perspective view showing an embodiment of a display device according to the present invention. The same parts as those in the basic configuration shown in FIGS. 1 to 7 are denoted by the same reference numerals, and description thereof is omitted.

  As shown in the figure, the display device according to the first embodiment includes a transparent light guide plate 1 and a light source 4 that is provided along an end surface 1a of the light guide plate 1 and includes LED elements. . As in FIG. 1, the light guide plate 1 has a plurality of reflection surfaces 2 b that reflect light from the light source 4 incident from the end surface 1 a of the light guide plate 1 to the surface (image display surface) 1 b side of the light guide plate 1. A dot-like reflecting portion 2 (concave portion) is formed.

  The display device also includes a protective plate 25 provided on the front surface (image display surface) 1b side with the light guide plate 1 interposed therebetween, and a protective plate 26 provided on the back surface 1c side. The pair of protective plates 25 and 26 is for suppressing the formation of scratches and the adhesion of dirt on the image display surface 1 b and the back surface 1 c of the light guide plate 1. The protection plates 25 and 26 are made of an acrylic resin that can transmit light, and are formed in a rectangular plate shape that is slightly larger than the light guide plate 1. The protective plates 25 and 26 are fixed to the light guide plate 1 by a fixing frame (not shown) through a gap (forms an air layer) G of about 1 to 2 mm in order to suppress the generation of interference fringes.

  In particular, in the present embodiment, antireflection films 27, 28, 29, 30, 31, and 32 are provided on the front and back surfaces of the light guide plate 1 and the protective plates 25 and 26, respectively. The antireflection films 27 to 32 are formed of a multilayer antireflection film (AR coating), and can prevent reflection of the light source light reflected by the recess 2.

<Other embodiments>
FIG. 9 illustrates a configuration in which the antireflection films 27, 28, 30, and 32 are provided only on the protection plates 25 and 26, and no antireflection film is provided on the front and back surfaces of the light guide plate 1.

  If the light guide plate 1 is provided with a reflective coat, it may cause scattering, and is provided only on the protective plates 25 and 26.

  In the display device of the embodiment shown in FIG. 10, antireflection films 27 and 28 are provided only on the front and back surfaces of the protection plate 25 provided on the image display surface 1 b side of the light guide plate 1, and on the back surface 1 c side of the light guide plate 1. The protective plate 26 provided has a configuration in which an antireflection film is not provided. This is because providing the protective plate 25 closest to the eyes of the observer is considered to have the greatest effect of suppressing reflection.

  The display device of the embodiment shown in FIG. 11 includes a second light guide plate 31 in addition to the first light guide plate 1, and a light source 33 serving as a second light source in addition to the first light source 4. The display device is different from the display device shown in FIG. 9 in that an image display unit is configured by two light guide plates 1 and 31.

  The first and second light guide plates 1 and 31 are stacked with a predetermined gap G. A first light source 4 is provided on one end face 1 a of the first light guide plate 1, and a second light source 33 is provided on the other end face 31 a of the second light guide plate 31.

  A plurality of dot-like reflecting portions (concave portions) 2 are formed on the back surface 1 c of the first light guide plate 21. Similar to the first light guide plate 1, a plurality of dot-like reflecting portions 32 are also formed on the back surface of the second light guide plate 31. The dot-like reflecting portions 2 and 32 are formed to form a predetermined pattern, but the dot-like reflecting portion 2 of the light guide plate 2 and the dot-like reflecting portion 32 of the light guide plate 31 may form different patterns. preferable.

  In the display device having the above configuration, the two display units may be displayed simultaneously by turning on both the light sources 4 and 33 serving as the light sources, or the display unit may be displayed by turning on one of the light sources 4 and 33. Either of them may be displayed. Moreover, the display part displayed by operation of the light sources 4 and 33 can also be changed with time. Thus, since the display device shown in FIG. 11 includes the two light guide plates 1 and 31, a plurality of patterns can be displayed, and the design of the displayed pattern can be improved.

  In addition, light from the light sources 4 and 33 is guided to the image display surface side through the respective light guide plates 1 and 31 and the dot-like reflection portions 2 and 32. The antireflection films 27 and 28 effectively act to prevent unnecessary reflection, and it is possible to configure a display device having a very good appearance.

  Further, since the two light guide plates 1 and 31 are arranged in the thickness direction, the positions of the light guide plates 21 and 22 in the thickness direction are different from each other, so that a three-dimensional effect can be given to the displayed pattern. For this reason, the display effect and decoration are very excellent.

  The light emission time, the light emission amount, and the light emission color of the light sources 4 and 33 may be constant, but one or more of the light emission time, the light emission amount, and the light emission color may be changed over time. The amount of light emission can be changed by changing the input power to the light source.

  By changing the light emission time, light emission amount, light emission color, and the like of the light sources 4 and 33, a change can be given to the displayed pattern.

  For example, by appropriately setting the order of light sources to be turned on, time, and the like, it is possible to display as if the pattern (pattern) is moving, and the display effect can be further improved.

  In this embodiment, the light guide plates 1 and 31 have a configuration in which an antireflection film is not provided. However, the light guide plates 1 and 31 are provided with an antireflection film in both the light guide plates 1 and 31. Any one of them may be provided with an antireflection film. Moreover, when providing an anti-reflective film, the structure provided in the image display surface side and back surface side of a light-guide plate, or any surface may be sufficient. Further, the number of light guide plates is not limited to two, but may be three or may be four or more.

1 is a perspective view schematically showing a display device according to 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 dot-shaped reflection part of the display apparatus shown in FIG. It is process drawing which shows the manufacturing method of the display apparatus shown in FIG. It is process drawing following a previous figure. It is process drawing following a previous figure. 1 is a perspective view schematically showing an embodiment of a display device according to the present invention. It is a perspective view which shows typically other embodiment of the display apparatus which concerns on this invention. It is a front view which shows typically other embodiment of the display apparatus which concerns on this invention. It is a front view which shows typically other embodiment of the display apparatus which concerns on this invention.

Explanation of symbols

1 Light guide plate (first light guide plate)
1a, 31a End surface 1b Surface (image display surface)
1c Back surface 1d End 2 Dot-shaped reflection (recess)
2a Reflecting surface 3 Display section (image display surface)
4, 33 Light source 10 Display device 25, 26 Protection plate 27, 28, 29, 30, 31, 32 Antireflection film 31 Second light guide plate

Claims (2)

A transparent light guide plate,
A light source provided along an end surface of the light guide plate;
A plurality of concave portions provided on the light guide plate and having a reflection surface that reflects light from the light source incident from an end surface of the light guide plate to the image display surface side of the light guide plate;
A protective plate provided on at least one of the image display surface side and the opposite surface side of the light guide plate;
An antireflection film provided on at least one of the image display surface of the light guide plate, the opposite surface of the light guide plate, the surface of the protection plate, or the back surface of the protection plate;
A display device comprising: An image display unit formed by laminating a plurality of transparent light guide plates;
A light source provided along each end face of the laminated light guide plate;
A plurality of concave portions provided on each of the light guide plates, each having a reflection surface that reflects light from the light source incident from an end surface of the light guide plate to the image display surface side of the light guide plate;
A protective plate provided on at least one of the front side or the back side of the image display unit;
An antireflection film provided on at least one of the image display surface of each light guide plate, the opposite surface of each light guide plate, the surface of the protection plate, or the back surface of the protection plate;
A display device comprising:

Images