JP3241230B2 - Tablet - Google Patents

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 and a CRT.
More particularly, the present invention relates to a tablet installed on the front surface of a tablet and for inputting coordinates on a display screen, and in particular, electrically connects a first transparent electrode formed on a glass substrate and a second transparent electrode formed on a film substrate. Related to the configuration of the transfer.

[0002]

2. Description of the Related Art As shown in FIG. 5, a tablet has a flexible glass substrate 2 having a first transparent electrode 1 formed on one side and a polyethylene terephthalate having a second transparent electrode 3 formed on one side. A film substrate 4 formed using a conductive film, a transfer 5 for electrically connecting the first and second transparent electrodes 1 and 3, and between the first and second transparent electrodes 1 and 3. Transparent insulating spacer 6 arranged
And an adhesive layer for bonding the outer peripheral portions of the glass substrate and the film substrate, for example, a double-sided adhesive tape 7.

[0003] The first transparent electrode 1 is formed uniformly over substantially the entire surface of one side of a glass substrate 2 using a transparent conductor such as ITO, for example.
The routing circuit 8 is not directly involved in the coordinate input.
On the other hand, the second transparent electrode 3 is also formed on substantially the entire surface of one side of the film substrate 4 by using a transparent conductor such as ITO, and the end of the second transparent electrode 3 has a coordinate as shown in FIG. The routing circuit 9 is not directly involved in the input.

[0004] The substrates 2 and 4 have the first and second transparent electrodes 1 and 3 inside and an insulating spacer 6 interposed between the electrodes 1 and 3 so that a frame placed on the outer periphery is provided. It is stuck by the double-sided adhesive tape 7 having a shape. At this time, the transfer 5 applied on one of the transparent electrodes is
It is pressed against the other transparent electrode, and the first and second transparent electrodes 1 and 3 conduct. The transfer 5 is heat-treated and solidified after bonding the substrates. The transfer 5 is generally provided in a cutout formed in the double-sided adhesive tape 7. After the transfer 5 has been solidified, as shown in FIGS. 6 and 7, the routing circuit 8 is grounded via the voltmeter 10 and the routing circuit 9 is grounded to obtain a desired tablet.

[0005] In the tablet constructed as described above, for example, a liquid crystal display device or a CR
It is installed on the front of a display device such as T. In this case, since the electrodes 1, 3, the substrates 2, 4, and the insulating spacer 6 are all made of a transparent material, the display screen of the display device can be clearly seen through the tablet. In addition, since the film substrate 4 can be bent by pressing the film substrate 4 toward the glass substrate 2 with a finger or a pen point or the like, the transparent electrode 3 of the pressing portion is pressed against the glass substrate 2 opposed thereto. It can be selectively brought into contact with the transparent electrode 1.

The x coordinate of the contact portion P can be represented by a ratio l ₁ / l ₂ of the distances l ₁ and l ₂ from the contact portion P to the routing circuit 9 . The ratio l ₁ / l ₂ of the distance from the contact portion P to the routing circuit 9 is shown in FIG. 6 and its equivalent circuit, FIG.
When R ₁ and R ₂ are resistance values proportional to the distances l ₁ and l ₂ , V is an applied voltage, and v ₁ and v ₂ are voltages divided by the contact portion P, l ₁ / l ₂ = _R 1 / _{R 2}
Since = _v in 1 / _{v 2} of the relationship can be determined by detecting the partial pressure ratio _v 1 / _{v 2} by voltmeter 10. Similarly, the y coordinate of the contact portion P can be determined by detecting the partial pressure ratio of the transparent electrode including the contact portion P among the transparent electrodes included in the first transparent electrode 1. Therefore, when the user operates the tablet in accordance with the display content on the display screen, the coordinates (x, y) of the contact portion P are obtained.
Can be input.

In this type of tablet, since the glass substrate 2 and the film substrate 4 are bonded via the insulating spacer 6 and the double-sided adhesive tape 7, the transparent electrodes 1, 3
In between, an air layer 11 is formed which is regulated by the diameter of the insulating spacer 6 and the thickness of the double-sided adhesive tape adhesive 7. Therefore, when the temperature of the tablet changes, the air layer 11 expands or contracts, and a stress acts on the transfer 5. At the same time, a stress acts on the transfer 5 due to the difference in the coefficient of thermal expansion between the glass substrate 2 and the film substrate 4.

Conventionally, in determining the quantity, arrangement, and application area of the transfer 5, no consideration has been given to the load of the transfer 5 that increases due to a change in the temperature of the tablet. This is done empirically due to the design needs of other elements. For this reason, at present, peeling of the transfer 5 accounts for most of the causes of tablet breakage.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned deficiencies of the prior art, and to provide a tablet having excellent durability, in which the transfer hardly peels off even under severe environmental conditions.

[0010]

The present invention SUMMARY OF] In order to achieve the above object, TD direction due to expansion or shrinkage of the film substrate F _TD (direction perpendicular to the stretching direction of the film)
Of stress, FMD, _{MD due} to expansion or contraction of film substrate
Direction stress (stretching direction of the film), in the TD direction by expansion or contraction of the air within the tablet F _TD 'stress, F _MD
MD direction of the stress due to expansion or contraction of the air within the tablet ', sigma a transfer of shear strength, when the S _T and transfer the coating area, the stress acting on the transfer is to satisfy the following inequality Next, the arrangement and application area of a plurality of transfers were adjusted.

[0011]

(Equation 3)

[0012]

When the number, arrangement, and application area of the transfer are adjusted so as to satisfy the above inequality, the stress acting on the transfer due to the difference in thermal expansion coefficient between the glass substrate and the film substrate, and the stress of the glass substrate and the film substrate, The transfer does not peel due to the stress acting on the transfer due to the expansion or contraction of the air layer formed therebetween, thereby improving the durability of the tablet. Further, since the margin ratio of the transfer destruction is set to 1/4, the transfer is not easily broken by other illegal external force, and the durability of the tablet is improved.

As described above, the transfer is generally provided in the notch formed in the double-sided adhesive tape. Therefore, when the tablet temperature becomes higher than the solidification temperature of the transfer, the expansion of the air in the notch causes the transfer in the peeling direction. Stress occurs. However, since the solidification temperature of the transfer is as high as 80 ° C. to 90 ° C., the tablet temperature is not considered to be high under normal use conditions, and the stress in the peeling direction can be ignored.

[0014]

FIG. 1 shows a tablet according to a first embodiment. In this figure, reference numeral 12 denotes a transfer setting notch provided on the double-sided adhesive tape 7, and other portions corresponding to those in FIG. 5 described above are denoted by the same reference numerals. As is clear from this figure, in the tablet of the present example, an interval equal to or less than 1/2 of the length of the glass substrate 2 and the film substrate 4 in the short side direction is provided in the bonding area where the short side on the signal input / output side is bonded. Two transfer setting notches 12 are opened, and one transfer point 5 is provided in each of the notches 12. However, the width of the glass substrate 2 and the film substrate 4 is 131 mm.
A frame-shaped double-sided adhesive tape 7 having a length of 173 mm and an inner peripheral width of 120 mm and a length of 15 mm is used.
The thing of 5 mm was used. Also, change the MD direction of the film
The film substrate 4 was directed in the long side direction.

[0015] 50mm the transfer distance T _DL in the width direction of the tablet, the transfer of the shear strength sigma 62kg
f / cm ^{2 The} coefficient of linear expansion α _TD in the width direction of the film substrate 4 is 0.0000.
12 / ° C., the coefficient of linear expansion α _MD in the longitudinal direction of the film substrate 4 is 0.000015 / ° C., the coefficient of linear expansion α _G of the glass substrate 2 is 0.0000099 / ° C., and the Young's modulus E of the film substrate 4 is
Is 515 kgf / mm ² (−40 to −30 ° C.), the transfer curing temperature T ₀ is 80 ° C., and the thickness t of the film substrate 4 is
Is 0.175 mm, the plane area S _A of the inner circumference (view area) of the double-sided adhesive tape 7 is 18600 mm ² , the volume V _A1 of the inner circumference of the double-sided adhesive tape 7 at the time of bonding is 1488 mm ³ ,
The volume V _A2 at the inner periphery of -30 ° C. in the double-sided adhesive tape 7 12
13 mm ³ , the number n of transfers formed on one side is 2
And the temperature range T when using the tablet is -30 ° C to +
By solving the above inequality for the diameter z of the transfer 5 at 80 ° C., the transfer 5 can be obtained even at T = −30 ° C. where the shearing force acting on the transfer 5 becomes the largest.
It has been found that if the diameter z is 0.17 mm or more, peeling can be prevented.

When a tablet according to the present embodiment with z = 2.8 was prepared and subjected to a heat cycle test of 200 cycles in a temperature range of -30 ° C. to + 70 ° C., no peeling occurred in the transfer 5. Further, generation of Newton rings due to deterioration of the film substrate 4 was not required.

<Second Embodiment> FIG. 2 shows a tablet according to a second embodiment. In this figure, parts corresponding to those in FIG. 1 described above are denoted by the same reference numerals. As is apparent from this figure, in the tablet of this example, five transfer setting notches 12 are provided at regular intervals (31 mm pitch) in the bonding area where the long sides of the glass substrate 2 and the film substrate 4 are bonded. , And the transfer 5 is provided in each of the notches 12 at one point. However, a glass substrate 2 and a film substrate 4 having a width of 131 mm and a length of 173 mm are used, and the frame-shaped double-sided adhesive tape 7 has an inner peripheral width of 1 mm.
20 mm and a length of 155 mm were used.

[0018] 125mm to transfer distance T _DL in the width direction of the tablet, the transfer of the shear strength σ 48.
The linear expansion coefficient α _TD in the width direction of the 3 kgf / cm ² film substrate 4 is 0.0000.
12 / ° C., the linear expansion coefficient α _MD in the longitudinal direction of the film substrate 4 is 0.000015 / ° C., the linear expansion coefficient α _G of the glass substrate 2 is 0.0000599 / ° C., and the Young's modulus E of the film substrate 4 is
Is 515 kgf / mm ² (−40 to −30 ° C.), the curing temperature T _{0 of the} transfer is 90 ° C., and the thickness t of the film substrate 4 is
Is 0.175 mm, the plane area S _A of the inner circumference (view area) of the double-sided adhesive tape 7 is 18600 mm ² , the volume V _A1 of the inner circumference of the double-sided adhesive tape 7 at the time of bonding is 1488 mm ³ ,
The volume V _A2 at the inner periphery of -30 ° C. in the double-sided adhesive tape 7 12
13mm ³ , distance d between adjacent transfer is 31m
m, the number n of the transfer formed on one side is 5, the temperature range T at the time of using the tablet is −30 ° C. to + 70 ° C., and the above inequality is solved for the diameter z of the transfer 5 to act on the transfer 5. Even at T = −30 ° C. where the shearing force is greatest, the diameter z of the transfer 5
Is set to 3.1 mm or more, peeling can be prevented.

When a tablet according to the present embodiment with z = 1.0 was prepared and subjected to a heat cycle test in a temperature range of -30 ° C. to + 70 ° C., the transfer 5 was peeled off.

Third Embodiment FIG. 3 shows a tablet according to a third embodiment. In this figure, parts corresponding to those in FIG. 1 described above are denoted by the same reference numerals. As is clear from this figure, in the tablet of this example, two transfer setting notches 12 are relatively positioned near the short side on the signal input / output side in the bonding area where the long sides of the glass substrate 2 and the film substrate 4 are bonded. And two notches 12
It is characterized in that a transfer 5 is provided as one set. However, as the glass substrate 2 and the film substrate 4,
The width is 70 mm, the length is 126 mm, and the frame-shaped double-sided adhesive tape 7 is 64 mm in inner circumference,
The one having a length of 118 mm was used.

[0021] 66mm the transfer distance T _DL in the width direction of the tablet, the transfer of the shear strength sigma 62kg
f / cm ^{2 The} coefficient of linear expansion α _TD in the width direction of the film substrate 4 is 0.0000.
12 / ° C., the linear expansion coefficient α _MD in the longitudinal direction of the film substrate 4 is 0.000015 / ° C., the linear expansion coefficient α _G of the glass substrate 2 is 0.0000599 / ° C., and the Young's modulus E of the film substrate 4 is
Is 515 kgf / mm ² (−40 to −30 ° C.), the transfer curing temperature T ₀ is 80 ° C., and the thickness t of the film substrate 4 is
Is 0.125 mm, the flat area S _A of the inner periphery (view area) of the double-sided adhesive tape 7 is 7552 mm ² ,
The volume V _A1 of the inner circumference of the double-sided adhesive tape 7 at the time of bonding is 604 mm ³ , and the volume V _A2 of the inner circumference of the double-sided adhesive tape 7 at -40 ° C. is 422 m.
m ³ , the distance d between adjacent transfers is 46 mm, the number n of transfers formed on one side is 2, the temperature range T when the tablet is used is −40 ° C. to + 80 ° C., and the diameter z of the transfer 5 is as described above. Solving the inequality
T = maximum shear force acting on the transfer 5
Even at −40 ° C., the diameter z of the transfer 5 is set to 0.3.
It was found that peeling could be prevented if the thickness was 7 mm or more.

When the tablet according to the present embodiment with z = 1.0 was prepared and subjected to a heat cycle test of 200 cycles in a temperature range of -40 ° C. to + 70 ° C., no peeling occurred in the transfer 5. Further, generation of Newton rings due to deterioration of the film substrate 4 was not required.

<Fourth Embodiment> FIG. 4 shows a tablet according to a fourth embodiment. In this figure, parts corresponding to those in FIG. 1 described above are denoted by the same reference numerals. As is apparent from this figure, in the tablet of this example, three transfer setting notches 12 are provided at equal intervals (46 mm pitch) in the bonding area where the long sides of the glass substrate 2 and the film substrate 4 are bonded. The transfer 5 is provided so as to be opposed to each other, and two notches 12 are provided in the notch 12. However, a glass substrate 2 and a film substrate 4 having a width of 70 mm and a length of 126 mm are used, and a frame-shaped double-sided adhesive tape 7 having a width of an inner periphery of 64 mm and a length of 118 mm is used. Was used.

[0024] 66mm the transfer distance T _DL in the width direction of the tablet, the transfer of the shear strength sigma 62kg
f / cm ^{2 The} coefficient of linear expansion α _TD in the width direction of the film substrate 4 is 0.0000.
12 / ° C., the linear expansion coefficient α _MD in the longitudinal direction of the film substrate 4 is 0.000015 / ° C., the linear expansion coefficient α _G of the glass substrate 2 is 0.0000599 / ° C., and the Young's modulus E of the film substrate 4 is
Is 515 kgf / mm ² (−40 to −30 ° C.), the transfer curing temperature T ₀ is 80 ° C., and the thickness t of the film substrate 4 is
Is 0.125 mm, the flat area S _A of the inner periphery (view area) of the double-sided adhesive tape 7 is 7552 mm ² ,
The volume V _A1 of the inner circumference of the double-sided adhesive tape 7 at the time of bonding is 604 mm ³ , and the volume V _A2 of the inner circumference of the double-sided adhesive tape 7 at -40 ° C. is 422 m.
m ³ , the distance d between adjacent transfers is 46 mm, the number n of transfers formed on one side is 6, the temperature range T when the tablet is used is −40 ° C. to + 80 ° C., and the diameter z of the transfer 5 is as described above. Solving the inequality
T = maximum shear force acting on the transfer 5
Even at −40 ° C., the diameter z of the transfer 5 is set to 1.3.
It was found that when the thickness was not less than mm, peeling could be prevented.

When a tablet according to the present embodiment with z = 1.0 was prepared and subjected to a heat cycle test in a temperature range of -40 ° C. to + 80 ° C., the transfer 5 was peeled.

[0026]

As described above, according to the present invention,
Since the number, arrangement, and application area of the transfer were adjusted to satisfy the inequality according to claim 1, the stress acting on the transfer due to the difference in thermal expansion coefficient between the glass substrate and the film substrate, and the glass substrate and Due to the stress acting on the transfer due to the expansion or contraction of the air layer formed between the film substrates, the transfer does not peel off, and a tablet with excellent durability can be provided.

[Brief description of the drawings]

FIG. 1 is a plan view of a tablet according to a first embodiment.

FIG. 2 is a plan view of a tablet according to a second embodiment.

FIG. 3 is a plan view of a tablet according to a third embodiment.

FIG. 4 is a plan view of a tablet according to a fourth embodiment.

It is a cross-sectional view of the tablet according to [5] Conventional Example

FIG. 6 is an explanatory diagram showing a principle of detecting coordinates of a contact portion in the tablet.

FIG. 7 is an equivalent circuit diagram of FIG. 6;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 first transparent electrode 2 glass substrate 3 second transparent electrode 4 film substrate 5 transfer 6 insulating spacer 7 double-sided adhesive tape 11 air layer 12 notch

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tatsuya Moriike 1-7 Yukiya Otsuka-cho, Ota-ku, Tokyo Alps Electric Co., Ltd. (58) Field surveyed (Int. Cl. ⁷ , DB name) G06F 3 / 033 H01H 13/52

Claims (1)

(57) [Claims] 1. A glass substrate having a first transparent electrode formed on one side and a film substrate having a second transparent electrode formed on one side, with the first and second transparent electrodes being on the inside,
A tablet formed by bonding the outer periphery thereof and providing a fine air layer between the first and second transparent electrodes and electrically connecting these two electrodes via a plurality or a plurality of sets of transfer. A tablet, wherein the arrangement and application area of the plurality of transfers are adjusted such that the total stress acting on the transfer satisfies the following inequality. (Equation 1) Where: Here, F _TD is a stress in the TD direction due to expansion or contraction of the film substrate F _MD is a stress in the MD direction due to expansion or contraction of the film substrate F _TD ′ is a stress in the TD direction due to expansion or contraction of air in the tablet. Stress F _MD ′ is stress in the MD direction due to expansion or contraction of air in the tablet MD direction is the stretching direction of the film TD direction is the direction perpendicular to the MD direction T _DL is the transfer between the width directions of the tablet The distance σ is the transfer shear strength ST _T is the transfer coating area α is the linear expansion coefficient difference between the film substrate and the glass substrate E is the film substrate Young's modulus T is the tablet temperature T ₀ is the transfer temperature curing temperature z is the transfer of diameter t, the thickness S _a of the film substrate, the plane area V _A1 of the air layer in the view area, Byueri The volume V _A2 at bonding of the air layer of the inner, the volume d at the time of measurement of the air layer in the view area, the distance n between the adjacent transfer, the number of transfer which is formed on one side.