JP2012118284A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device which can perform switching smoothly when a view point of an observer positioned at the front side changes, while preventing a visual field range from being different between an image drawn at a reflective scattering part at the upper layer side and an image drawn at a reflective scattering part at the lower layer side, even when at least two light guide plates each having the reflective scattering part are overlapped.SOLUTION: A display device comprises a light guide plate laminate 50 formed by overlapping two light guide plates 20 and 21 on each other, light sources 22 and 23 for making light incident on the light guide plates 20 and 21 from end faces 20A and 21A thereof, and a mask 24 or a lense array provided on the surface side of the light guide plate laminate 50. Reflective scattering parts 25 and 26 are formed on opposing surfaces 20B and 21B of the two light guide plates 20 and 21 respectively, for reflecting and scattering light that is emitted from the light sources 22 and 23 and made incident from the end faces 20A and 21A so as to emit the light from a surface of the light guide plate laminate 50.

Description

  The present invention relates to a display device used for a display or the like, and more particularly to a display device that displays an image in a stereoscopic manner.

  As a stereoscopic display method for displaying an image so as to be stereoscopically visible with the naked eye, a method using parallax such as a parallax barrier method or a lens array method is known. In the parallax barrier method, a mask in which light-shielding portions and openings are alternately arranged at a constant repetition pitch (parallax barrier) is used, and images for each of a plurality of viewpoints are divided behind the masks and arranged at the repetition pitch. Arrange the images. With such a configuration, different images can be seen for each viewpoint using parallax. In the lens array method, a lens array (lenticular lens) in which minute lenses are arranged at a constant repetition pitch is used instead of a mask. The same.

  The divided and arranged images are usually printed matter or a liquid crystal display screen. In addition, a certain distance is required between the mask and lens array and the image. In the case of the parallax barrier method, a spacer having a certain thickness is sandwiched between the mask and the image, or the image is directly on the back surface of the spacer. Printed. In the case of the lens array method, a lens array with a thickness that can maintain the required distance may be used, and the image may be printed directly on the printed material or the liquid crystal display screen, or directly on the back of the lens array. Many.

  As a method of displaying an image, in addition to the printed matter and the liquid crystal display device, the light guide plate is processed to have unevenness by cutting, laser processing, or other molding, and a light source such as an LED is connected to the end face of the light guide plate to make light incident Thus, a method of displaying a specific image by reflecting and scattering light with the unevenness of the light guide plate is known. By combining such a light guide plate and a mask or a lens array, it is also possible to construct a display system that stereoscopically displays a light emitting image (for example, Patent Document 1). When the light guide plate is used, the light guide plate itself has a constant thickness, and thus it is possible to adopt a configuration that does not require the spacer as described above.

The shape of the unevenness that reflects and scatters light incident on the light guide plate is not particularly limited, but it is efficient even with a small area in plan view by making a concave notch with a substantially triangular cross section with a flat and smooth reflecting surface. Therefore, it is possible to display a brighter image even with fine expression.
The color of the image displayed by the light guide plate is usually the same as the color of the incident light. For example, the color of the incident light is white, and color filters of different colors are overlaid on the light guide plate for each location. Thus, color image representation is also possible.

JP 2003-295117 A

In the above-described method of reflecting and scattering light with the unevenness of the light guide plate to display a specific image, for example, as shown in FIG. 5, a plurality of light guide plates 3 each having a reflection scattering portion 2 composed of a plurality of recesses 5 are overlapped. By using the laminated body 10 (light guide plate laminated body), a plurality of images can be superimposed and displayed in a stereoscopic manner.
In the display device illustrated in FIG. 5, the light incident light source 1 is disposed on the end surface 3 </ b> A of each light guide plate 3, and the mask 4 and the transparent plate 6 as a spacer are disposed on the surface side of the laminate 10. ing.

However, in the display device of FIG. 5, the distances between the reflection / scattering portions 2, 2 provided on the respective light guide plates 3, 3 and the mask 4 are different. That is, the distance (referred to as D1) between the reflective portion 2 of the light guide plate 3 located in the upper layer of FIG. 5 and the mask 4 and the distance between the reflective portion 2 of the light guide plate 3 located in the lower layer and the mask 4 (reference symbol D2). Is different). For this reason, for example, the visual field range in which the first image formed by the light reflected from the reflection / scattering unit 2 on the upper layer side and the second image formed by the light reflected from the reflection / scattering unit 2 on the lower layer side are different may be observed. When the viewpoint is moved, the switching of the first image and the switching of the second image are shifted, and the switching of the images is not smooth. That is, it has been difficult for an observer to display a plurality of images in a stereoscopic manner so that the viewer does not feel uncomfortable.
Further, in the method of displaying an image using the printed matter or the liquid crystal display screen described above, it is difficult even to display a plurality of images in a superimposed manner.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a display device capable of displaying two images in a stereoscopic manner so that the viewer does not feel uncomfortable.

In order to solve the above problems, the present invention proposes the following means.
That is, the present invention provides a light guide plate laminate in which two light guide plates are overlapped, two light sources for allowing light to enter each of the two light guide plates from its end face, and the light guide plate laminate. A mask or a lens array provided on the front surface side of the two light guide plates, and the light from each of the two light sources incident from the end faces on the opposite surfaces of the two light guide plates to the light guide plate surface side Provided is a display device characterized in that a reflection / scattering part is formed which is reflected and scattered and emitted from the surface side of the light guide plate laminate.
The present invention also provides a display device characterized in that images of characters, pictures, patterns, symbols, figures, etc. are displayed by light reflection from the reflection / scattering section.
In the present invention, each of the two light guide plates is provided with a plurality of dot-like reflection parts each having a reflection surface that reflects light from each of the two light sources as the reflection / scattering part. Provided is a display device characterized in that a reflecting surface of a dot-like reflecting portion is in a range of 40 to 60 degrees with respect to a surface on which the dot-like reflecting portion is formed.
In addition, the present invention provides a display device characterized in that the dot-like reflecting portion is a V-shaped notch in a sectional view in which one of two opposing surfaces forms a reflecting surface.
The present invention also provides a display device characterized in that the respective dot-like reflecting portions of the two light guide plates of the light guide plate laminate are formed at different positions on opposite surfaces. .
In addition, the present invention provides a display device further comprising light emission control means for controlling light emission of two light sources provided respectively corresponding to two light guide plates independently of each other.

  According to the present invention, two images can be displayed so as to be stereoscopically viewed so that the observer does not feel uncomfortable.

It is a front sectional view of a display device showing the best embodiment of the present invention. FIG. 2 is an enlarged front sectional view of a main part of the display device of FIG. 1. FIG. 6 is a front sectional view showing a first modification of the display device in FIGS. 1 and 2. FIG. 6 is a front sectional view showing a second modification of the display device in FIGS. 1 and 2. It is a front sectional view of a conventional display device.

An embodiment of a display device according to the present invention will be described with reference to FIGS.
The display device S shown in FIGS. 1 and 2 has a light guide plate laminate 50 formed by superimposing two light guide plates 20 and 21, and light is incident on the light guide plates 20 and 21 from the end surfaces 20A and 21A. And a mask 24 for forming a parallax barrier on the surface side of the light guide plate laminate 50.

  The light from the light sources 22 and 23 incident from the end surfaces 20A and 21A is applied to each of the opposing surfaces 20B and 21B where the light guide plates 20 and 21 of the light guide plate laminate 50 are overlapped with each other. Reflection / scattering portions 25 and 26 are formed that are reflected and scattered (upper side in FIGS. 1 and 2) to be emitted from the surface of the light guide plate stack 50.

The light guide plates 20 and 21 are formed using a transparent resin such as acrylic resin, polycarbonate, silicone resin, or cyclopolyolefin resin, a glass plate, or the like.
In addition, the two light guide plates 20 and 21 have the opposing surfaces 20B and 21B in contact with each other with a weak force so that the opposing surfaces 20B and 21B are not in close contact with each other, or in a state where no pressing force is applied. 21B is brought into contact with each other.

Here, the light sources 22 and 23 are light emitting diodes, but are not limited thereto.
Incident light from the light sources 22 and 23 incident on the light guide plates 20 and 21 from the end surfaces 20A and 21A toward the end of the light guide plates 20 and 21 opposite to the end surfaces 20A and 21A. , 21 is propagated.

  The light emission (lighting) of the light sources 22 and 23 is controlled by power supply control of a power supply device 91 (see FIG. 1) that supplies power to the light sources 22 and 23. The light emission control (turning on and off) of the light sources 22 and 23 by the power supply device 91 may be synchronized between the light source 22 and the light source 23, or may cause the two light sources 22 and 23 to emit light at different timings. good. In the latter case, the power supply device 91 functions as a light emission control unit that performs light emission control of the two light sources independently of each other.

The reflection / scattering portions 25 and 26 are dot-like reflection portions composed of concave portions 27 and 28 formed in a triangular shape in a sectional view, and are formed on the opposing surfaces 20B and 21B of the two light guide plates 20 and 21. Each is arranged on the surface.
The concave portions 27 and 28 reflect and scatter incident light incident on the light guide plates 20 and 21 from the light sources 22 and 23 to the surface side that is the viewer side, on the end surfaces 20A and 21A side. Reflective surfaces 27A and 28A that emit light from the surface of 50 are provided.

Each of the concave portions 27 and 28 forming the dot-like reflecting portion is a V-shaped cutout in sectional view in which one of the two opposing surfaces forms the reflecting surfaces 27A and 28A.
The reflection surface 27A of the concave portion 27 of the light guide plate 20 on the surface side of the light guide plate laminate 50 is inclined with respect to the facing surface 20B so as to be separated from the end surface 20A from the back surface side of the light guide plate 20 to the surface side. It is an inclined surface.
On the other hand, the reflective surface 28A of the concave portion 28 of the light guide plate 21 on the back surface side of the light guide plate laminate 50 moves from the back surface side of the light guide plate 21 toward the surface side where the facing surface 21B exists with respect to the facing surface 21B. The inclined surface is inclined so as to be separated from the end surface 21A. In other words, the inclined surface is inclined so as to be closer to the end surface 21A from the front surface side to the back surface side of the light guide plate 21.

The inclination angles of the reflecting surfaces 27A and 28A of the concave portions 27 and 28 with respect to the opposing surfaces 20B and 21B of the light guide plates 20 and 21 (acute angles with respect to the opposing surfaces 20B and 21B) are 40 to 60 degrees.
Further, in each of the recesses 27 and 28, the reflection surfaces 27A and 28A are opposed to the incident light from the light sources 22 and 23 to the light guide plates 20 and 21, and from the light sources 22 and 23 of the incident light to the light guide plate 20. , 21 with respect to the incident optical axis at an inclination angle of about 40 to 60 degrees.

Further, a surface (hereinafter also referred to as a back surface) facing the reflective surface 27A of the concave portion 27 of the light guide plate 20 on the surface side of the light guide plate laminate 50 in the illustrated example, that is, the side opposite to the end surface 20A via the reflective surface 27A. Is formed perpendicular to the facing surface 20B, but the surface facing the reflecting surface 28A of the concave portion 28 of the light guide plate 21 on the back surface side of the light guide plate laminate 50 (the end surface 21A via the reflecting surface 28A). The opposite surface (back surface) is an inclined surface that inclines toward the reflection surface 28A from the rear end of the recess 28, which is a V-shaped cutout in cross section, with respect to a virtual vertical surface perpendicular to the facing surface 21B. ing.
However, the back surface of the concave portion 27 of the light guide plate 20 on the front surface side of the light guide plate laminate 50 is not necessarily a surface perpendicular to the facing surface 20B, and the inclination angle with respect to the facing surface 20B can be set as appropriate. The back surface may be, for example, an inclined surface that inclines toward the reflective surface 27A with respect to a virtual vertical surface perpendicular to the facing surface 20B from the back end of the concave portion 27 that is a V-shaped cutout in cross section. .

The reflecting surfaces 27A and 28A are preferably flat surfaces in terms of ensuring high reflection efficiency.
The plurality of concave portions 27 and 28 (dot-like reflective portions) formed as the reflection / scattering portions 25 and 26 can display images such as characters, designs, patterns, symbols, and figures as a whole by combining them. It is arranged.

As shown in FIG. 2, the mask 24 is a light shielding layer formed by printing light shielding ink on one surface of the transparent resin sheet 29. Note that the method of forming the mask is not limited to the method of printing the light shielding ink. That is, for example, it can be formed by other methods such as patterning of an exposure film and vapor deposition (formation of a vapor deposition film). On the surface side (front side) of the light guide plates 20 and 21, a masked sheet 29A formed by forming a mask 24 on one side of the transparent resin sheet 29 is laminated with the mask 24 facing the light guide plate laminate 50 side. Yes.
The mask 24 employs a structure composed of a parallax barrier that generates parallax by partially allowing light to pass through a light-transmitting portion such as a slit 24A or a hole at a predetermined interval according to a printing pattern of light-shielding ink. Yes. The portions other than the light transmitting portion of the mask 24 are light shielding portions.

In the display device S of the illustrated example, a spacer formed of a transparent plate indicated by reference numeral 30 is provided between the mask 24 and the light guide plates 20 and 21, and is superimposed on the surface side of the light guide plate laminate 50. The desired distances D3 and D4 can be accurately ensured by the structure in which the masked sheet 29A is laminated on the spacer 30 so that the mask 30 overlaps the spacer 30. However, the spacer 30 is brought into contact with the light guide plate 20 on the surface side (front side) of the light guide plate laminate 50, but is not brought into close contact therewith.
In place of such a spacer 30, for example, the entire periphery or a plurality of locations on the outer periphery of the masked sheet 29 </ b> A is supported by the support member with respect to the light guide plate stack 50, and the masked sheet 29 </ b> A The spacer portion in between may be used as a gap.

In the display device S, incident light from the light source 22 to the light guide plate 20 on the front surface side is reflected and scattered by the reflection / scattering unit 25 to the front surface side of the light guide plate 20 and light source 23 to the light guide plate 21 on the back surface side. The light that is reflected and scattered by the reflection / scattering unit 26 toward the surface of the light guide plate 21 can be observed from the surface of the mask 24 that is the viewer side. With the light from the reflection / scattering portions 25 and 26 of the optical plates 20 and 21, an image display which can be stereoscopically viewed from the mask 24 surface side can be performed.
In addition, the reflection / scattering part 25 of the light guide plate 20 on the front surface side of the light guide plate laminate 50 and the reflection / scattering part 26 of the light guide plate 21 on the back surface side are viewed from the front side of the light guide plate laminate 50. The positions are shifted from each other so that the positions do not coincide with each other.

  In addition, the display device S includes a distance (D3) between the reflection / scattering portion 25 of the upper light guide plate 20 and the mask 24, and a distance (D4) between the reflection / scattering portion 26 of the lower light guide plate 21 and the mask 24. Are substantially coincided with each other, so that the visual field range in which an image reflected by the light reflected from the reflection / scattering portion 25 of the upper light guide plate 20 is visible and the light reflected from the reflection / scattering portion 26 of the lower light guide plate 21 are reflected. The visual field range in which an image can be seen can be matched or substantially matched, and the switching of images when the observer's viewpoint changes is smooth. Therefore, the two images can be displayed in a stereoscopic manner so that the viewer does not feel uncomfortable.

(Modification 1)
In the above-described embodiment, the reflection / scattering portions 25 and 26 including the recesses 27 and 28 are provided on the opposing surfaces 20B and 21B of the light guide plates 20 and 21, but as shown in FIG. 21B (lower layer in FIG. 3), the concave portion (recessed by reference numeral 28 ') constituting the reflection / scattering portion 26 is smaller than the concave portion 27 of the other side reflection / scattering portion 25. It is good also as a simple shape.

That is, on the opposing surfaces 20B and 21B of the light guide plates 20 and 21, a roughening process having a plurality of minute recesses 28 'at a plurality of locations on the surface of the light guide plate 21 located in the lower layer by, for example, laser processing or sandblasting. The portion may be formed as the reflection / scattering portion 26.
Further, the reflection / scattering part 26 (roughening processing part) having such a large number of minute recesses 28 'is not the light guide plate 21 located in the lower layer as shown in FIG. 3, but the light guide plate 20 located in the upper layer. It may be formed on both the upper and lower light guide plates 20 and 21.

(Modification 2)
In the above embodiment, the mask 24 laminated on the front surface side (front surface side) of the light guide plates 20 and 21 is parallaxed by the translucent part having the slits 24A at predetermined intervals as shown in FIG. Although the structure is made of a parallax barrier to be generated, the present invention is not limited to this. As shown in FIG. 4, a convex minute lens that protrudes toward the device surface side (upper side in FIG. 4) instead of the mask. You may provide the lens array 40 (lenticular lens) of the structure where 41 is arranged in large numbers by the fixed repetition pitch.

(Modification 3)
Moreover, in the said embodiment, although the reflective scattering parts 25 and 26 which consist of recessed part 27, 28 or 28 'were provided in the opposing surfaces 20B and 21B of the light-guide plates 20 and 21, in addition to this, the light-guide plate 20 , 21 may also be formed with concave reflection scattering portions 25 and 26 that reflect the light from the light sources 22 and 23 to the front side (surface side) on the outer surfaces other than the opposing surfaces 20B and 21B. That is, in this example, in the light guide plate laminate 50 shown in FIGS. 1 to 3, the surface of the light guide plate 20 located on the upper layer side (indicated by reference numeral 20 </ b> C in FIG. 3) and the back surface of the light guide plate 21 located on the lower layer side. (Refer to reference numeral 21C in FIG. 3) may be provided with the reflection / scattering units 25 and 26 described above to realize various image expressions.
The reflection / scattering portions 25 and 26 provided on the front surface 20C of the light guide plate 20 and the back surface 21C of the light guide plate 21 may be relatively large triangular recesses 27 and 28 as shown in FIGS. 3 may be a minute triangular recess 28 'as shown in FIG.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, in the illustrated example, the configuration in which the positions of the end surfaces 20A and 21A of the two light guide plates 20 and 21 and the light sources 22 and 23 are aligned is illustrated, but the end surfaces 20A and 21A of the two light guide plates 20 and 21 and the light source are illustrated. The positions of 22 and 23 do not need to match. For example, a configuration in which the positions and orientations of the end faces 20A and 21A and the light sources 22 and 23 are different from each other can be adopted so that the two light guide plates 20 and 21 have different light axes of incident light from the light sources 22 and 23 by 90 degrees. It is.

  DESCRIPTION OF SYMBOLS 20 ... Light guide plate, 20A ... End surface, 20B ... Opposite surface, 20C ... Front surface, 21 ... Light guide plate, 21A ... End surface, 21B ... Opposite surface, 21C ... Back surface, 22 ... Light source, 23 ... Light source, 24 ... Mask, 24A ... Slit (light-transmitting part), 25: reflection / scattering part, 26 ... reflection / scattering part, 27 ... concave part, 28 ... concave part, 28 '... concave part, 40 ... lens array, 50 ... light guide plate laminate, 91 ... light emission control means ( Power feeding device), S ... display device.

Claims (6)

Provided on the surface side of the light guide plate laminate, a light guide plate laminate formed by superposing two light guide plates, two light sources for allowing light to enter each of the two light guide plates from its end face A mask or lens array,
Reflection that causes light from each of the two light sources incident from the end face to be reflected and scattered on the surface side of the light guide plate and emitted from the surface side of the light guide plate laminate, on each of the opposing surfaces of the two light guide plates A display device characterized in that a scattering portion is formed.   The display device according to claim 1, wherein an image such as a character, a pattern, a pattern, a symbol, or a figure is displayed by light reflection from the reflection / scattering unit.   Each of the two light guide plates is provided with a plurality of dot-like reflection parts each having a reflection surface that reflects light from each of the two light sources as the reflection / scattering part, and reflection of the dot-like reflection parts. The display device according to claim 1, wherein the surface is in a range of 40 to 60 degrees with respect to the surface on which the dot-shaped reflection portion is formed.   4. The display device according to claim 3, wherein the dot-like reflecting portion is a V-shaped notch in a sectional view in which one of two opposing surfaces forms a reflecting surface. 5.   5. The dot-shaped reflecting portion of each of the two light guide plates of the light guide plate laminate is formed so as to be at different positions on the opposing surfaces. 6. Display device.   6. The display device according to claim 1, further comprising light emission control means for controlling light emission of the two light sources respectively provided corresponding to the two light guide plates independently of each other.

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