JP2004185380A - Light guide unit and light-transmissive touch panel using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light guide unit used for various electronic appliances, allowing excellent visual recognition of display displayed on a display element even if repeating press slide operation onto the upper face of an upper substrate, and to provide a light-transmissive touch panel using it. <P>SOLUTION: In this light guide unit 12, a resin layer 13 formed on the upper face of a light guide plate 1 covers unevenness on the upper face of the light guide plate 1 to smooth the upper face, and a refractive index of the resin layer 13 is set to be lower than a refractive index of the light guide plate 1. The light-transmissive touch panel is configured by disposing both a lower substrate 3 formed with a lower electroconductive layer 4 on the upper face and the upper substrate 5 formed with an upper electroconductive layer 6 on the lower face, above the light guide unit 12. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a light guide unit used for input operation of various electronic devices and a light transmissive touch panel using the same.
[0002]
[Prior art]
In recent years, characters, symbols, pictures, and the like displayed on the display device are visually recognized through a light-transmitting touch panel mounted on the front surface of a display device such as an LCD, and the upper surface thereof is operated to select or determine a character. Due to the increasing number of various electronic devices, there is a need for a light-transmissive touch panel that can display characters, symbols, and the like satisfactorily.
[0003]
Such a conventional light transmissive touch panel will be described with reference to FIG.
[0004]
FIG. 2 is a cross-sectional view of a conventional light transmissive touch panel. In FIG. 2, reference numeral 1 denotes a light guide plate, and reference numeral 2 denotes a prism surface having irregularities formed on the upper surface of the light guide plate 1.
[0005]
Reference numeral 3 denotes a light-transmissive lower substrate mounted on the light guide plate 1. A light-transmissive lower conductive layer 4 is formed on the upper surface of the lower substrate. An electrode (not shown) is provided.
[0006]
Reference numeral 5 denotes a light-transmitting upper substrate, on which a light-transmitting upper conductive layer 6 is formed.
[0007]
On the lower surface of the upper conductive layer 6, a pair of upper electrodes (not shown) are provided at both ends in a direction orthogonal to the lower electrode, and a plurality of dot spacers for keeping a predetermined distance from the upper conductive layer 6 are provided. (Not shown) are formed at predetermined intervals.
[0008]
Reference numeral 8 denotes a frame-shaped spacer such as a nonwoven fabric or a polyester film. The upper substrate 5 and the lower substrate 3 are bonded to each other by an adhesive (not shown) applied to the upper and lower surfaces, and the lower surface of the upper substrate 5 is formed. The light transmissive touch panel is configured such that the upper conductive layer 6 and the lower conductive layer 4 on the upper surface of the lower substrate 3 face each other at a predetermined interval.
[0009]
In the above configuration, when the upper electrode and the lower electrode are connected to a detection circuit (not shown) of the electronic device, and the upper surface of the upper substrate 5 is pressed with a finger or a pen or the like, the upper substrate 5 is bent, and The upper conductive layer 6 is in contact with the lower conductive layer 4, and the pressed position is detected based on the resistance ratio between the upper electrode and the lower electrode.
[0010]
Further, light incident on the light guide plate 1 from a light source (not shown) arranged on the left side is reflected downward by the prism surface 2 on the upper surface of the light guide plate 1 and displayed on an LCD or the like arranged below the light guide plate 1. The element 9 is illuminated.
[0011]
Then, the illuminated light is reflected by a reflector (not shown) on the lower surface of the display element 9 or the like, and the reflected light passes through the light guide plate 1, the lower substrate 3, the lower conductive layer 4, the upper conductive layer 6, and the upper substrate 5. It is configured such that characters such as characters and symbols displayed on the display element can be viewed well from above by sequentially transmitting.
[0012]
As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
[0013]
[Patent Document 1]
JP-A-12-37041
[Problems to be solved by the invention]
However, in the above-described conventional light guide unit and the light transmissive touch panel using the same, when the pressing and sliding operation on the upper surface of the upper substrate 5 is repeated, the convex portion of the prism surface 2 is worn and the display element 9 is illuminated. Since the amount of light is reduced and the surface is darkened, there is a problem that it is difficult to visually recognize a display displayed on the display element 9.
[0015]
The present invention has been made to solve such a conventional problem, and a light guide unit and a light guide unit capable of favorably recognizing a display displayed on a display element even when pressing and sliding operations on an upper substrate upper surface are repeated. It is an object of the present invention to provide a light transmissive touch panel used.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has the following configuration.
[0017]
According to the first aspect of the present invention, the resin layer formed on the upper surface of the light guide plate fills the unevenness of the upper surface of the light guide plate to smooth the upper surface, and the refractive index of the resin layer is changed to the refractive index of the light guide plate. The light guide unit is configured to be smaller than the light guide unit. Even if the pressing and sliding operation of a pen or the like is repeated on the upper substrate upper surface of the light transmissive touch panel disposed on the light guide unit, the resin layer remains on the upper surface of the light guide plate. Since the upper surface is smoothed by filling the unevenness of the light guide plate, the convex portion of the light guide plate is not worn, so that the surface of the display element disposed below can be illuminated satisfactorily and the reflected light from the display element can be obtained. Is transmitted upward from the light guide plate toward the resin layer, so that a light guide unit capable of visually recognizing the display on the display element can be obtained.
[0018]
According to a second aspect of the present invention, in the first aspect of the present invention, unevenness of a visible wavelength or less is formed on the lower surface of the light guide plate. Since the light can easily pass through the lower surface, the surface of the display element disposed below the light guide plate can be illuminated more favorably.
[0019]
According to a third aspect of the present invention, in the first aspect of the present invention, an antireflection film is formed on a lower surface of the light guide plate, and light reflected downward by the prism surface on the upper surface of the light guide plate is less likely to pass through the lower surface of the light guide plate. Since the light is transmitted without being reflected, the surface of the display element disposed below the light guide plate can be illuminated more favorably.
[0020]
According to a fourth aspect of the present invention, a lower substrate having a lower conductive layer formed on an upper surface thereof is disposed above the light guide unit of the first aspect, and a lower surface thereof is opposed to the lower conductive layer with a predetermined gap. An upper substrate on which a conductive layer is formed is arranged to form a light-transmissive touch panel, and even if the pressing and sliding operation of a pen or the like is repeated on the upper surface of the light-transmissive upper substrate, the light-transmissive touch panel is disposed between the lower substrate and the light guide plate. Since the resin layer formed on the light guide plate fills the unevenness of the upper surface of the light guide plate and smoothes the upper surface, the projections of the light guide plate do not wear out, so that the light to the surface of the display element arranged below can be reduced. When performed well, there is an effect that a light transmissive touch panel capable of favorably recognizing a display displayed on a display element can be obtained.
[0021]
According to a fifth aspect of the present invention, in the fourth aspect of the present invention, a light guide plate having a resin layer formed on an upper surface is disposed in place of the lower substrate. This has the effect of reducing the thickness of the touch panel.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIG.
[0023]
The same components as those described in the section of the related art are denoted by the same reference numerals, and detailed description will be simplified.
[0024]
(Embodiment)
FIG. 1 is a cross-sectional view of a light transmissive touch panel according to an embodiment of the present invention. In FIG. It is.
[0025]
Reference numeral 2 denotes an irregular prism surface formed on the upper surface of the light guide plate 1 at a depth of about 10 μm and at an interval of about 150 μm, with a gentle slope on the left and a steep slope on the right.
[0026]
Reference numeral 13 denotes a light-transmitting resin layer having a refractive index smaller than that of the light guide plate 1 and formed by printing or the like so as to fill irregularities on the upper surface of the light guide plate 1 and to smooth the upper surface. ing.
[0027]
The resin layer 13 is made of an airgel such as a fluororesin having a refractive index of about 1.3 or a porous silica having a refractive index of about 1.0.
[0028]
Reference numeral 3 denotes a light-transmissive lower substrate such as glass or acrylic or polycarbonate resin, or a laminate of polyethylene terephthalate or polycarbonate film, and a light-transmissive lower substrate such as indium tin oxide or tin oxide. A lower conductive layer 4 is formed by sputtering or the like, and a pair of lower electrodes (not shown) is provided at both ends of the lower conductive layer 4.
[0029]
The lower surface of the lower substrate 3 is bonded to the upper surface of the resin layer 13 with an adhesive (not shown) made of a thermoplastic resin such as an acrylic resin or a polyester resin.
[0030]
Reference numeral 5 denotes a light-transmitting upper substrate such as a polyethylene terephthalate or polycarbonate film, and on the lower surface thereof, a light-transmitting upper conductive layer 6 similar to the lower conductive layer 4 is formed.
[0031]
On the lower surface of the upper conductive layer 6, a pair of upper electrodes (not shown) are provided at both ends in a direction orthogonal to the lower electrode, and a plurality of dot spacers for keeping a predetermined distance from the upper conductive layer 6 are provided. (Not shown) are formed at predetermined intervals by an insulating material such as epoxy or silicon.
[0032]
Reference numeral 8 denotes a frame-shaped spacer such as a nonwoven fabric or a polyester film. The upper substrate 5 and the lower substrate 3 are bonded to each other by an adhesive applied on the upper and lower surfaces thereof, and the upper conductive layer 6 on the lower surface of the upper substrate 5 is formed. The light transmissive touch panel is configured such that the lower conductive layer 4 and the upper surface of the lower substrate 3 face each other at a predetermined interval.
[0033]
In the above configuration, when the upper electrode and the lower electrode are connected to a detection circuit (not shown) of the electronic device, and the upper surface of the upper substrate 5 is pressed with a finger or a pen or the like, the upper substrate 5 is bent, and The upper conductive layer 6 is in contact with the lower conductive layer 4, and the pressed position is detected based on the resistance ratio between the upper electrode and the lower electrode.
[0034]
Even if the pressing and sliding operation with a pen or the like is repeated on the upper surface of the upper substrate 5, the resin layer 13 formed between the lower substrate 3 and the light guide plate 1 fills the unevenness on the upper surface of the light guide plate 1 and smoothes the upper surface. Therefore, the projections of the light guide plate 1 are not worn, and the surface of the display element 9 arranged below is illuminated favorably.
[0035]
Light incident on the light guide plate 1 from a light source (not shown) arranged on the left side is reflected downward by the prism surface 2 on the upper surface of the light guide plate 1, and is displayed on an LCD or the like arranged below the light guide plate 1. The element 9 is illuminated.
[0036]
The illuminated light is reflected by a reflector (not shown) on the lower surface of the display element 9 or the like, and the reflected light is reflected by the light guide plate 1, the resin layer 13, the lower substrate 3, the lower conductive layer 4, the upper conductive layer 6, The display is configured so that characters such as characters and symbols displayed on the display element 9 can be visually recognized from above from the upper substrate 5 in order.
[0037]
At this time, since the refractive index of the resin layer 13 is smaller than the refractive index of the light guide plate 1, the reflected light from the display element 9 is transmitted well upward from the light guide plate 1 toward the resin layer 13.
[0038]
As described above, according to the present embodiment, the resin layer 13 formed on the upper surface of the light guide plate 1 fills the unevenness of the upper surface of the light guide plate 1 to smooth the upper surface, and the refractive index of the resin layer 13 is reduced by the light guide plate. The light guide unit 12 is configured to have a refractive index smaller than 1 and the lower substrate 3 having the lower conductive layer 4 formed on the upper surface and the upper substrate 5 having the upper conductive layer 6 formed on the lower surface. The resin layer 13 fills the irregularities on the upper surface of the light guide plate 1 and smoothes the upper surface even if pressing and sliding operations with a pen or the like are repeated on the upper surface of the light transparent upper substrate 5 by arranging the light transmissive touch panel. Therefore, the projections of the light guide plate 1 are not worn, and the surface of the display element 9 arranged below is satisfactorily illuminated, and the reflected light from the display element 9 is transmitted from the light guide plate 1. By favorably transmitting upward toward the resin layer 13, the display element 9 Those which can be visually displayed, which is displayed to obtain a light-transmitting touch panel using a light guide unit 12 and which allows better.
[0039]
Further, by forming irregularities of visible wavelength or less on the lower surface of the light guide plate 1, visible light reflected downward on the prism surface 2 on the upper surface of the light guide plate 1 easily passes through the lower surface of the light guide plate 1. Illuminating the surface of the display element 9 disposed in the above.
[0040]
The prism surface 2 is formed on the lower surface of the light guide plate 1 by forming an anti-reflection film such as a fluororesin having a small refractive index, silica, magnesium fluoride or the like to reduce the reflectance by transmitting light by vacuum deposition or sputtering. Thus, the light reflected downward passes through the lower surface of the light guide plate 1 without being much reflected, so that the surface of the display element 9 disposed below the light guide plate 1 can be more favorably illuminated.
[0041]
Further, even if the antireflection film is formed by alternately stacking a plurality of light-transmitting materials having a small refractive index and large refractive materials such as titania and indium tin oxide on the lower surface of the light guide plate 1 in the same manner as described above. Illumination on the surface of the display element 9 can be performed more favorably.
[0042]
Then, instead of the lower substrate 3, a lower conductive layer 4 is formed on the upper surface of the resin layer 13 by sputtering, printing, or the like, and the lower conductive layer 4 and the upper conductive layer 6 of the upper substrate 5 face each other with a predetermined gap therebetween. As described above, by forming the light transmissive touch panel by laminating the outer periphery with the spacer 8 interposed therebetween, the lower substrate 3 becomes unnecessary, so that the light transmissive touch panel can be made thinner.
[0043]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a light guide unit and a light transmissive touch panel using the same, in which even if the pressing and sliding operation on the upper substrate upper surface is repeated, the display displayed on the display element can be viewed well. The advantageous effect that it can be obtained is obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a light transmissive touch panel according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of a light transmissive touch panel according to a conventional embodiment.
REFERENCE SIGNS LIST 1 light guide plate 2 prism surface 3 lower substrate 4 lower conductive layer 5 upper substrate 6 upper conductive layer 8 spacer 9 display element 12 light guide unit 13 resin layer

Claims (5)

A light guide plate having an uneven prism surface that reflects light incident from a light source disposed on the side downward, formed on the upper surface, and a resin layer formed on the upper surface of the light guide plate. A light guide unit that fills the unevenness of the light guide plate to make the upper surface smooth, and that the refractive index of the resin layer is smaller than the refractive index of the light guide plate. The light guide unit according to claim 1, wherein the light guide plate is provided with irregularities of a visible wavelength or less on a lower surface thereof. The light guide unit according to claim 1, wherein an antireflection film is formed on a lower surface of the light guide plate. A lower substrate having a lower conductive layer formed on an upper surface thereof, and an upper substrate having an upper conductive layer formed on a lower surface thereof opposed to the lower conductive layer with a predetermined gap therebetween. Light transmissive touch panel arranged. The light transmissive touch panel according to claim 4, wherein a lower conductive layer is formed on the upper surface of the resin layer instead of the lower substrate.

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