JP3484764B2 - Coordinate input device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate input device which is provided on a display screen of a display device so as to be superposed on the display screen and is used for handwriting input of characters and figures using a stylus pen or the like.

[0002]

2. Description of the Related Art A coordinate input device of this type, which is also called a touch panel, is used by superposing it on a liquid crystal display panel attached to an electronic notebook, a notebook personal computer, a word processor or the like. It must be transparent enough to show the displayed contents.

As shown in FIGS. 2 (a) and 2 (b), a conventional touch panel (hereinafter, referred to as an input panel) is made of a transparent material such as an ITO (indium tin oxide) film as a resistance film. A transparent glass substrate 2 on which the electrode 1 is uniformly coated, and a transparent film 3 of, for example, polyethylene terephthalate, on which the transparent electrode 1 made of the ITO film is uniformly coated, are made of an insulating transparent acrylic resin. The transparent glass substrate 2 and the transparent film 3 are opposed to each other with a spacer 4 formed between them, and the respective ends of the transparent glass substrate 2 and the transparent film 3 are bonded with an adhesive 5 such as a double-sided tape. Then, the transparent glass substrate 2 is placed on the display screen of the liquid crystal display panel 7 with the transparent glass substrate 2 facing downward.

In the input operation, a voltage is applied to each transparent electrode 1 of the transparent glass substrate 2 and the transparent film 3 in time series, and a predetermined position on the upper (visual side) transparent film 3 is made of an insulating polyacetal. When pressed with the input pen 8 made of resin, the upper and lower transparent electrodes 1 at the pressed position (coordinate position) come into contact with each other, and this contact position is detected as a resistance change, and is output as coordinate data via a control circuit (not shown). To be done.

The substrate of this input panel is usually a transparent glass plate or a transparent film such as acrylic or polyester resin. Further, in order to prevent external light (external light), for example, natural light such as sunlight, illumination light such as a fluorescent light from being reflected on the input panel surface, and preventing the display content from being difficult to see due to the reflected light, A so-called non-glare treatment is performed to process the surface of the substrate (transparent film) on the visual side into an uneven shape to eliminate gloss and diffusely reflect incident light.

The non-glare treatment includes frost treatment, that is, a method of roughening the surface of the visual side substrate by immersing it in an aqueous solution of hydrofluoric acid, or silica coating, that is, the surface of the substrate being oxidized. There is a method in which a liquid in which fine particles such as silicon (SiO ₂ ) are mixed with a resin is applied and the fine particles are dispersed to make the surface of the substrate uneven.

[0007] The degree of non-glare treatment for making the transparent substrate surface uneven is determined by the glossiness (anti-glare degree) of the transparent substrate surface.
And haze value (cloud value). The glossiness is determined by illuminating the sample surface with light from a standard light source at a specified angle (standard is 60 degrees) based on JIS K 7105-1981, Optical property testing method for plastics, page 4, 5.2.1. It is described that the reflected component is measured with a light receiver, and the reflection of external light (
The reflection can be defined as in Equation 1.

[0008]

[Equation 1]

Here, the reference plane of Equation 1 is JIS K 7105-198.
1, plastic optical property test method, page 4, 5.2.
A glass surface with a refractive index of 1.567 shall be used as described in the gloss type of 2 and the specular gloss standard of 5.2.3, and the gloss value in this case shall be 100%.

The haze value is JIS K 7105-1981, and the integrating sphere type light transmittance measuring device shown in FIGS. 5 and 6 and Table 4 on pages 8 to 9 of the method for testing optical characteristics of plastics is used. According to JIS K 7105-1981, 6.15 of the optical property test method for plastics, 6.4.4 on page 15 to 16, the diffuse transmittance and the total light transmittance can be measured, and the ratio can be shown as the formula 2. Therefore, when external light such as illumination light is incident on the surface of the input panel, it is possible to regulate the scattering of the incident light.

[0011]

[Equation 2]

FIG. 3 shows the results of measuring both the above-mentioned glossiness and haze value by subjecting either one of the front and back surfaces of a polyethylene terephthalate film to a non-glare treatment and using this as a sample. The vertical axis of the figure is glossiness (%)
And the horizontal axis shows the haze value (%). As is clear from this figure, the larger the haze value, the smaller the glossiness. That is, as the haze value increases, the diffuse transmittance increases, that is, the diffuse reflectance decreases, and the glossiness decreases.

Therefore, it can be understood that it is preferable to increase the haze value in order to reduce the reflection (reflection) of external light.
However, if the haze value is increased, the display content of the liquid crystal display panel below the input panel becomes difficult to see. In other words, there is a problem that the character is enthusiastic.

The ambiguity of characters is defined by the image clarity. Image sharpness is JIS K 7105-1981, as shown in 6.6.1 on page 17 of the method for testing optical properties of plastics, the light passing through or reflected by the sample is moved using an image sharpness measuring device. It is stipulated that the image is measured through an optical comb and calculated, and this image measuring device is shown in 6.6.2 of page 17 to 18 of the method for testing optical properties of plastics.

Further, the test piece is 6.6.4 on page 18 and is 6.6.4.
The measurement method is described in 6.6.5, and the image sharpness calculation method is described in 6.6.5. FIG. 4 shows the relationship between the image sharpness and the haze value when a polyethylene terephthalate film, which has been subjected to non-glare treatment on either the front or back surface, is used as a sample. In the figure, the vertical axis shows the image definition (mm) and the horizontal axis shows the haze value (%). As is clear from this figure, the image definition increases as the haze value increases, and when the haze value exceeds 20%, the display resolution of the liquid crystal display panel
It is worse than the value of 0.25 mm.

In other words, as the haze value increases, the image definition increases, the display resolution decreases, and the character is blurred.

[0017]

Conventionally, as described above, the haze value is set to about 20% only on the surface of the transparent film of polyethylene terephthalate on the visual side of the input panel, that is, the side where the input pen is pressed. It was non-glare processed.

However, if the non-glare processing is performed so as to obtain such a haze value, there is a problem that the image clarity is increased and the character is blurred. Further, when the non-glare treatment is applied only to the surface in this way, the incident light as shown by the arrow A is diffusely reflected as B at the surface side of the transparent film 3 as shown in FIG. The light passes through the transparent film 3 and reaches the back surface side of the film, and the reflected light indicated by C reflected on the back surface side enters the eyes of the input operator. Therefore, the antiglare effect is still insufficient. It was

The present invention has been made in view of the above-mentioned findings, and it is a coordinate system that secures the resolution necessary for display and that reduces the deterioration of visibility due to the reflection of light from the outside on the visual side substrate. The input device is provided.

[0020]

According to the present invention, when the haze value is increased to prevent the reflection of external light such as illumination light, the character is blurred and the resolution deteriorates. The main point is that non-glare treatment has been applied to both sides of the transparent substrate.

More specifically, the coordinate input device of the present invention comprises:
As set forth in claim 1, wherein a spacer is arranged between the transparent film and the transparent substrate, and a spacer is arranged between the transparent film and the transparent substrate, and transparent electrodes are provided on the surfaces of the transparent film and the transparent substrate which face each other. In a coordinate input device in which the display section is arranged on the transparent substrate side, the transparent film is
The front and back surfaces of the light film are subjected to a non-glare treatment to reduce the haze value to 18% or less , and then the back surface of the transparent film is subjected to the above-mentioned treatment.
A coordinate input device comprising a transparent electrode .

Further, as shown in claim 2, characterized in that subjected to non-glare treatment by both sides in the drawing of the transparent film.

[0023]

As shown in FIG. 1, when non-glare treatment is applied to the front and back surfaces of the transparent film 3 on the visual side of the input pen to give unevenness, the incident light A is first incident on the surface 3A of the transparent film 3.
Diffused reflection occurs, and only the incident light having a reduced light amount passes through the transparent film 3 and reaches the back surface 3B side of the film.

Next, since the back surface 3B side of the transparent film 3 is also subjected to the non-glare treatment similarly to the front surface 3A side,
Diffuse reflection occurs, and the amount of light reflected from the back side to the front side of the input operator's eyes decreases, that is, the amount of external light reflected on the panel can be reduced.

If the haze value is set to 18% or less, the display contents on the liquid crystal display panel under the input panel can be clearly recognized without causing the characters to be blurred, and the visibility is high. Specifically, as shown in FIG. 4, when the haze value is set to 18% or less, the image sharpness becomes 0.25 mm or less, which is the resolution of the dot pitch of the liquid crystal display panel, and the image sharpness is the resolution of the display dot pitch. Haze value of 10% or less, preferably 8% to keep 1/2 of 0.125mm or less
You can do the following:

However, as shown in FIG. 3, as the haze value is decreased, the glossiness increases, and the amount of reflected light reflected becomes large. Therefore, when the transparent substrate is a polyethylene terephthalate film, the glossiness is The haze value of 2%, which is 100%, is the lower limit.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a sectional view of an embodiment of the coordinate input device of the present invention. As shown in the figure, the input panel 6 that constitutes the coordinate input device of the present invention has, for example, a resistance film of the input panel on its inner surface and is made of ITO (indium / tin / oxide).
A transparent glass substrate 2 having a transparent electrode 1 made of transparent acrylic resin, and a transparent glass substrate 2 facing the transparent glass substrate 2 with a spacer 4 made of a transparent acrylic resin between the transparent glass substrate 2 and the transparent electrode 1. The transparent film 3 is made of terephthalate.

On both the front and back surfaces of this transparent film 3, the incident light shown by the arrow A is scattered on the surface of the transparent film 3,
In addition, the light transmitted through the transparent film 3 is transmitted to the transparent film 3
Is subjected to non-glare processing to prevent the reflection of external light (for example, light of a fluorescent lamp) on the input panel 6 by reflected light.

In this non-glare treatment, both the front and back surfaces of the transparent film 3 are drawn, and then a hard coat treatment is carried out. As the drawing process, a hot press method was used in which the transparent film was pressed against a drawing die to form a drawing die.
The height from the concave-convex concave portion to the convex portion of this non-glare treatment was about 0.5 to 2.0 μm, and the pitch from the convex portion to the convex portion was about 50 to 300 μm.

As the haze value, 1/2 of the display dot pitch of the liquid crystal display panel 7 arranged on the lower side (resolution 0.12
5 mm) or less, 2 to both sides of the transparent film
It was set to about 8%. As a result, it was experimentally confirmed that it is possible to sufficiently prevent the reflection of the panel due to the light from the outside and to obtain a high-quality input panel that does not cause the blur of characters.

As another non-glare treatment, a method may be used in which a fine glass ball or the like is directly applied to a transparent film to apply a pressure to the transparent film to form a diaphragm die. Further, as another non-glare treatment, a hard coat treatment in which fine particles of silicon dioxide (SnO ₂ ) or the like are mixed with a hard coat agent and applied to a transparent film and dispersed to form a diaphragm mold may be used.

The above-mentioned non-glare processing method is simpler than the above-mentioned conventional non-glare processing method and can form a uniform uneven surface. As the above-mentioned hard coat agent, an acrylic resin, a urethane resin, or the like can be used. Further, the drawing process and the hard coat process described above can be simultaneously performed.

After the front and back surfaces of the transparent film 3 have been subjected to the non-glare treatment as described above, the transparent electrode 1 serving as a resistance film is formed on the back surface of the transparent film 3. In order to form the transparent electrode 1, ITO may be formed on the back surface of the film by vapor deposition such as vapor deposition, sputtering, and CVD.
Alternatively, a coating method of dissolving ITO in an organic solvent and coating it on the back surface of the film may be used.

In addition to the ITO (In ₂ O ₃ -SnO ₂ , indium / tin / oxide) film, a tin oxide (SnO ₂ ) film and a zinc oxide (ZnO ₂ ) material can be used as the material of the transparent electrode 1 serving as a resistance film. ) A film or the like may be used.

As the material of the spacer 4, a soft transparent material that does not cause scratches on the transparent electrode 1, for example, acrylic resin or urethane resin is used. The spacer has a width of 50 μm and a pitch of 250 to 700 μm, Thickness 2.0 ~
Place as 8.0 μm.

As the transparent film 3 on the visual side of the input panel, a flexible film made of resin such as polyether sulfone may be used in addition to polyethylene terephthalate. As the transparent substrate arranged on the display panel side of the input panel, a transparent plastic sheet or the like may be used in addition to the transparent glass substrate 2.

As the display unit, a PDP, EL, CRT or the like can be applied in addition to the liquid crystal display panel. As described above, by performing the non-glare treatment on both the front and back surfaces of the transparent film on the visual side, the ambient light is diffusely reflected on both the front and back surfaces of the film, and the amount of light incident on the eyes of the input operator is reflected. By reducing the haze value to 18% or less, the display contents of the liquid crystal display panel under the input panel can be clearly viewed without any confusion, which makes it highly visible and highly reliable. A quality coordinate input device can be obtained.

[0038]

As described above, according to the coordinate input device of the present invention, it is possible to prevent the display contents from being dim and to prevent the reflection on the input panel by external light such as illumination light. It is possible to obtain a resolved high-quality, highly reliable coordinate input device with good visibility.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embodiment of an input panel of the present invention.

FIG. 2 is a sectional view of a conventional input panel and a sectional view of an operating state of the panel.

FIG. 3 is a relationship diagram between the glossiness of the visual side film of the input panel and the haze value.

FIG. 4 is a diagram showing the relationship between the haze value of the visual side film of the input panel and the image clarity.

[Explanation of symbols]

1 transparent electrode 2 transparent glass substrate 3 transparent film 4 spacers 5 adhesive 6 Input panel 7 LCD display panel 8 input pen

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-5-217462 (JP, A) JP-A-6-148621 (JP, A) JP-A-5-50561 (JP, A) JP-A-64- 32330 (JP, A) JP 5-324172 (JP, A) JP 5-307105 (JP, A) Actual opening 5-12972 (JP, U) Actual opening Sho 63-143827 (JP, U) 63-24580 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G06F 3/03 G06F 3/033-3/037

Claims (2)

(57) [Claims] 1. A transparent electrode disposed on a display part, wherein a spacer is disposed between a transparent film and a transparent substrate, and transparent electrodes are provided on opposite surfaces of the transparent film and the transparent substrate. in the coordinate input device in which the display unit is disposed on the substrate side, the transparent film is Nong on both surfaces of the transparent film
After applying a rare treatment to reduce the haze value to 18% or less ,
A coordinate input device in which the transparent electrode is formed on the back surface of a bright film . 2. The coordinate input device according to claim 1, wherein both the front and back surfaces of the transparent film are non-glare processed by drawing.