JPH0990316A - Liquid crystal display device with touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device with a touch panel which is not affected in display by the pressing force from a touch panel side and obviates the occurrence of the degradation in contrast. SOLUTION: The thickness of a rear surface glass substrate 12a is made thinner than the thickness of a front surface glass substrate 11 formed with transparent electrodes and is more preferably set at <=2/3 the thickness thereof and the touch panel 2 is so combined as to come into substantial tight contact with the surface of the front surface glass substrate 11 at the time of combining a liquid crystal display element 1 a formed by interposing a peripheral sealing material 13 between the front surface glass substrate 11 and the rear surface glass substrate 12a and disposing both substrates opposite to each other and sealing liquid crystals 14 into a cell enclosed by the peripheral sealing material 13 and the touch panel 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device with a touch panel, and more particularly, to a liquid crystal display device with a touch panel in which the display quality is not affected by the pressing force applied to the touch panel. is there.

[0002]

2. Description of the Related Art A liquid crystal display element has been used as a display for all kinds of electronic devices in recent years. Among them, in the field of personal computers, word processors and the like, it is combined with a touch panel as an input means, for example, a handwriting by an input pen The liquid crystal display device of the hybrid type, which is capable of faithfully displaying the above, has been attracting attention.

As a typical example, FIG. 4 schematically illustrates a hybrid type liquid crystal display device in which a pressure sensitive touch panel 2 is combined with a liquid crystal display element 1 with its cross section. Since the configurations of the liquid crystal display element 1 and the pressure-sensitive touch panel 2 itself are already well known in various documents,
The description will be briefly described below.

The liquid crystal display element 1 includes a pair of transparent glass substrates 11 and 12, and although not shown, the glass substrate 1
Transparent electrodes made of ITO (a mixed film of indium oxide and tin oxide) or the like are formed on one surface of each of 1 and 12. The glass substrates 11 and 12 are arranged to face each other with a peripheral sealing material (sealing material) 13 sandwiched between their respective electrode formation surfaces, and a liquid crystal is provided in a cell surrounded by the peripheral sealing material 13. 14 is enclosed.

Although not shown in FIG. 4, a large number of pixels corresponding to one display dot are arranged in a matrix between the glass substrates 11 and 12, and the other of the glass substrates 11 and 12 is actually arranged. Polarizing plates 15 and 16 are adhered to the surface of, ie, the outer surface side thereof.

The pressure-sensitive touch panel 2 has a plastic sheet 21 made of PET (polyethylene terephthalate) or the like and a transparent glass substrate 22, which are arranged to face each other with a fine spacer 23 sandwiched between them. Has a transparent and uniform sheet resistance film.

By pushing the surface of this panel with, for example, an input pen, the plastic sheet 21 at that portion is deformed so that the sheet resistance films contact each other, and the resistance division ratio of the sheet resistance film at that time is divided into voltage or current distribution. By measuring the ratio, the position of the pressing point can be obtained relatively easily.

By the way, generally, the thickness of the plastic sheet 21 of the touch panel 2 is about 0.2 mm, while the thickness of each of the glass substrates 11, 12, 22 of the liquid crystal display element 1 and the touch panel 2 is about 1 mm. Although it is about 1 mm, when the pressing force is applied to the liquid crystal display element 1 in accordance with a pen input operation, for example, the influence appears on the liquid crystal display.

In other words, when the glass substrate 11 on the front side is bent by the pressing force from the touch panel 2, the liquid crystal 1
The gap width between the glass substrates 11 and 12 in which 4 is encapsulated changes, and this causes interference color in the pressing portion and its periphery. In addition, the alignment of the liquid crystal 14 is disturbed, and the contrast is lowered. The pressure-sensitive touch panel has been described above as an example. However, also in a touch panel of another method such as a capacitance method, the same adverse effect occurs on the liquid crystal display due to the pressing force applied to the contact portion of the touch pen or the fingertip.

For this reason, conventionally, the spacer 3 is interposed between the liquid crystal display element 1 and the touch panel 2, and a gap of about 0.5 to 2 mm is provided between the spacer 3 and the touch panel 2.
The pressing force from is not transmitted to the liquid crystal display element 1.

[0011]

However, since the spacer 3 is interposed, the thickness of the liquid crystal display device as a whole becomes large, which is not preferable for making the device thinner. Further, since the respective surfaces of the glass substrate 11 of the liquid crystal display element 1 and the glass substrate 22 of the touch panel 2 which are opposed to each other with the spacer 3 interposed therebetween serve as reflecting surfaces, reflection of external light and reflection of display light occur, making it difficult to see the display. Become.

The present invention has been made in order to solve such a conventional problem, and its object is to prevent the display from being affected even when a pressing force is applied from the touch panel side, and to reduce the thickness of the entire device. An object of the present invention is to provide a liquid crystal display device with a touch panel that can be made even thinner.

[0013]

In order to achieve the above-mentioned object, the invention of claim 1 has a front glass substrate and a rear glass substrate on which transparent electrodes are formed with a peripheral sealing material interposed therebetween. A liquid crystal display element in which liquid crystal is enclosed in a cell surrounded by a peripheral sealing material is provided while facing each other.
In a liquid crystal display device with a touch panel in which a touch panel is arranged on the front glass substrate side of the liquid crystal display element, a glass substrate having a thickness smaller than that of the front glass substrate is used as the rear glass substrate, and It is characterized in that the touch panel is mounted so as to be substantially in close contact with.

Further, the invention of claim 2 is characterized in that the thickness of the rear glass substrate is set to ⅔ or less of the thickness of the front glass substrate.

According to the present invention, since the back glass is formed thinner than the front glass as described above, when the pressing force is applied to the front glass, the back glass is deformed so that the back glass bends following the pressing force. To do. As a result, the gap in which the liquid crystal is filled is kept almost at the initial width, and the interference color is hardly generated and the contrast is not lowered.

Therefore, the touch panel can be installed so as to be in close contact with the front glass of the liquid crystal display element without using a spacer, and the thickness of the entire device can be reduced by removing the spacer. . However, since the front glass is actually provided with a polarizing plate, the present invention also includes that the touch panel is installed on the polarizing plate.

Further, since the touch panel is directly attached to the liquid crystal display element, there is no reflection loss of light and the display is easy to see. In particular, when the liquid crystal display element is a reflection type, the back glass is formed thin, so that the parallax (parallax) between the display image from the liquid crystal and the reflection image from the reflection plate on the back surface of the back glass is small, and the contrast is low. Good display can be obtained.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Next, in order to better understand the technical idea of the present invention, an embodiment thereof will be described with reference to FIGS. In these figures, the same or similar parts as those of the liquid crystal display device of FIG. 4 described above are designated by the same reference numerals.

FIG. 1 is a sectional view of an embodiment according to the present invention in which a liquid crystal display element 1a and a pressure-sensitive touch panel 2 are directly combined, and FIG. 2 is a partially enlarged sectional view thereof. According to this, the liquid crystal display element 1a includes the front glass substrate 11 and the rear glass substrate 12a, but in this case, the rear glass substrate 12a is made of a glass substrate thinner than the front glass substrate 11. There is.

As described above, the purpose of thinning the rear glass substrate 12a is to obtain easier bending than the front glass substrate 11, and in the present invention, the rear glass substrate 12a is made.
Is 2/3 of the thickness of the front glass substrate 11.
The materials are front glass substrate 11 and rear glass 12.
Both a may be a transparent inorganic glass such as soda glass which is commonly used.

Although not shown, a transparent electrode made of an ITO film or the like is formed in a predetermined pattern on one surface of each of the front glass substrate 11 and the rear glass substrate 12a as in the conventional case. The front glass substrate 11 and the back glass substrate 12a are arranged opposite to each other with a peripheral sealing material (sealing material) 13 sandwiched between their respective electrode formation surfaces, and are surrounded by the peripheral sealing material 13. A liquid crystal 14 is enclosed inside. In addition, the other surface of the glass substrates 11 and 12a,
That is, polarizing plates 15 and 16 are attached to the outer surface sides thereof, respectively.

The touch panel 2 is the same as that used in the liquid crystal display device of FIG. 4 described above, and therefore its explanation is omitted. However, in the present invention, the touch panel 2 is closely attached to the front glass substrate 11. Are arranged as follows.
In this example, the double-sided adhesive tape 4 is arranged around the polarizing plate 15 on the front glass substrate 11, and the liquid crystal display element 1a and the touch panel 2 are integrally joined by the double-sided adhesive tape 4. .

When the reflection type is used, the rear glass substrate 1
A light reflection plate is provided on the polarizing plate 16 on the side of 2a. In this case, since the rear glass substrate 12a is thinly formed, a display image from the liquid crystal 14 and a reflection image from the reflection plate on the rear surface of the rear glass are formed. A parallax (parallax) is small and a display with good contrast can be obtained.

On the other hand, FIG. 3 shows an example in which the liquid crystal display device with a touch panel is combined with the illumination unit 5 to form a transmissive type. In any case, it is preferable to use, as the polarizing plate 15 on the front glass substrate 11 side, one having fine irregularities on the surface and subjected to anti-glare treatment, because the occurrence of Newton's rings between the liquid crystal display element and the touch panel can be suppressed. .

[0025]

[Examples] Next, various thicknesses of the rear glass substrate of the liquid crystal display device were changed, a predetermined pressing force was actually applied from the touch panel side to the front glass substrate, and the influence of the pressing force on the display was observed. , Explain about it. In each example, the touch panel has a PE of 0.1 mm.
A touch panel composed of a T sheet and a 1.1 mm glass substrate is used, and the diameter of the tip is 1.6 mm and the curvature is 0.8 mm from the touch panel to the front glass substrate.
A pressing force of 250 g / cm 2 was applied with a polyacetal touch pen.

Comparative Example 1 When the thickness of both the front glass substrate and the rear glass substrate was 1.1 mm, the influence on the display (generation of interference color) was clearly recognized, and the contrast was deteriorated. <Example 1> When the rear glass substrate was 0.7 mm with respect to the front glass substrate 1.1 mm, the display was slightly affected, but it was not a problem and the contrast was slightly deteriorated. Met. Example 2 The front glass substrate was 1.1 mm and the rear glass substrate was 0.55 mm. The display was not affected, and the contrast was good. Example 3 The front glass substrate was 1.1 mm and the back glass substrate was 0.3 mm. Similar to Example 2, the display was not affected and the contrast was good.

<Comparative Example 2> When both the front glass substrate and the rear glass substrate have a thickness of 0.7 mm, as in Comparative Example 1, the influence on the display (generation of interference color) is clearly recognized and the contrast is improved. Also deteriorated. <Comparative Example 3> The front glass substrate was 0.7 mm, and the rear glass substrate was 0.55 mm. Although not as great as Comparative Example 2, the influence on the display was recognized and the contrast was considerably lowered. Example 4 The front glass substrate was 0.7 mm and the rear glass substrate was 0.4 mm. Without affecting the display
The contrast was also good. Example 5 The rear glass substrate was 0.2 mm while the front glass substrate was 0.7 mm. Similar to Example 5, the display was not affected and the contrast was good.

For reference, the observation results of Comparative Examples 1 to 3 and Examples 1 to 5 are shown in Table 1, and the thickness of the rear glass substrate is set to 2/3 or less of the thickness of the front glass substrate. Thus, it was confirmed that even if a pressing force is applied to the liquid crystal display element along with the input to the touch panel, the display is not affected by this and the contrast is not deteriorated.

[0029]

[Table 1]

[0030]

As described above, according to the present invention,
In a liquid crystal display device with a touch panel in which a liquid crystal display element and a touch panel are combined, the thickness of the rear glass substrate of the liquid crystal display element is thinner than that of the front glass substrate, and preferably 2/3 or less of the thickness of the front glass substrate. As a result, the display is not affected by the pressing force, and the reduction in contrast can be prevented.

Therefore, the touch panel can be combined with the liquid crystal display element without providing a gap between them, and a liquid crystal display device with a touch panel can be provided which is even thinner.

Further, since the touch panel is directly attached to the liquid crystal display element without providing a gap in this manner, there is no light reflection loss and the display is easy to see.
In particular, when the liquid crystal display element is a reflection type, the back glass is formed thin, so that the parallax (parallax) between the display image from the liquid crystal and the reflection image from the reflection plate on the back surface of the back glass is small, and the contrast is low. The effect that a good display is obtained is exhibited.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a liquid crystal display device with a touch panel according to the present invention.

FIG. 2 is a partially enlarged cross-sectional view of the same embodiment.

FIG. 3 is a partially enlarged cross-sectional view of an example in which a liquid crystal display device with a touch panel according to the embodiment is combined with an illumination unit to form a transmissive type.

FIG. 4 is a sectional view showing a conventional liquid crystal display device with a touch panel.

[Explanation of symbols]

 1a Liquid crystal display element 2 Pressure sensitive touch panel 4 Double-sided adhesive tape 5 Lighting unit 11 Front glass substrate 12a Rear glass substrate 13 Peripheral sealing material 14 Liquid crystal 15 and 16 Polarizing plate

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[Procedure amendment]

[Submission date] September 27, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction contents]

[0025]

[Examples] Next, various thicknesses of the rear glass substrate of the liquid crystal display device were changed, a predetermined pressing force was actually applied from the touch panel side to the front glass substrate, and the influence of the pressing force on the display was observed. , Explain about it. In each example, the touch panel has a PE of 0.1 mm.
A touch panel composed of a T sheet and a 1.1 mm glass substrate is used, and the diameter of the tip is 1.6 mm and the curvature is 0.8 mm from the touch panel to the front glass substrate.
A pressing force of 250 g was applied with a polyacetal touch pen.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuro Matsuda 3-14-19 Yushima, Bunkyo-ku, Tokyo Optrex Co., Ltd.

Claims (2)

[Claims] 1. A front glass substrate on which a transparent electrode is formed and a back glass substrate are arranged to face each other with a peripheral sealing material interposed therebetween, and in a cell surrounded by the peripheral sealing material. A liquid crystal display device with a touch panel, comprising a liquid crystal display element enclosing a liquid crystal, wherein a touch panel is arranged on the front glass substrate side of the liquid crystal display element, wherein the rear glass substrate has a thickness smaller than that of the front glass substrate. A liquid crystal display device with a touch panel, characterized in that a substrate is used and the touch panel is mounted on the front glass substrate so as to be in close contact with each other. 2. The liquid crystal display device with a touch panel according to claim 1, wherein the thickness of the back glass substrate is set to ⅔ or less of the thickness of the front glass substrate.