Patent Application
20110169761
The present invention relates to touch panels, display devices including the same, and liquid crystal display devices.
A touch panel (touch screen) is a device for inputting information to an information processing device, such as a computer etc., in an interactive manner by touching (pressing) the panel using a finger, a pen, etc.
There are different types of touch panels based on different operating principles: resistive; capacitive; infrared; ultrasonic; electromagnetic inductive; etc. Resistive and capacitive touch panels are recently most commonly used in display devices etc., because of the low cost of mounting.
The resistive touch panel includes, for example, a pair of substrates facing each other, a pair of transparent conductive films provided as resistive films on inner surfaces of the pair of substrates, an insulating spacer interposed between the pair of substrates to form an air layer between the pair of transparent conductive films, and a position detection circuit which detects a touch position. The resistive touch panel is, for example, mounted on the front surface of the display screen of a liquid crystal display panel.
In the resistive touch panel thus configured, when the front surface of the touch panel is touched, the pair of transparent conductive films contact each other (make a short circuit), so that a current flows between the pair of transparent conductive films. Based on a change in voltage when a current flows between the pair of transparent conductive films, the position detection circuit detects the touch position.
Incidentally, a liquid crystal display panel includes, for example, an active matrix substrate and a counter substrate facing each other, and a liquid crystal layer provided between the active matrix substrate and the counter substrate. Therefore, when the resistive touch panel is mounted on the front surface of the liquid crystal display panel of the liquid crystal display device, there are four constituent substrates, i.e., the pair of substrates included in the touch panel, the active matrix substrate, and the counter substrate, resulting in an increased overall thickness of the display device.
To avoid this, for example, PATENT DOCUMENT 1 describes a touch sensor type liquid crystal display device in which a color filter substrate of a liquid crystal display panel is used as a fixed electrode plate of a touch sensor, whereby a fixed electrode plate which is otherwise typically included in a touch sensor panel is removed. As a result, the thickness and weight of the touch sensor type liquid crystal display device can be reduced, and in addition, a degradation in optical characteristics can be advantageously reduced or prevented.
In the subject matter described in PATENT DOCUMENT 1, however, the touch sensor type liquid crystal display device includes three constituent substrates, and therefore, there is a room for improvement. For example, in recent years, a liquid crystal display device (liquid crystal display panel) including a matrix type resistive touch panel has been proposed.
The liquid crystal display device including the matrix type resistive touch panel includes, for example, a plurality of first touch panel interconnects provided as a resistive film on a surface closer to the liquid crystal layer of the active matrix substrate, extending in parallel with each other, and a plurality of second touch panel interconnects provided as another resistive film on a surface closer to the liquid crystal layer of the counter substrate, extending in parallel with each other in a direction perpendicular to the first touch panel interconnects. When a surface of the active matrix substrate or the counter substrate is pressed, a first touch panel interconnect and a second touch panel interconnect corresponding to the pressed position contact each other at the pressed position, whereby conduction is established therebetween. Here, each first or second touch panel interconnect has a columnar touch pin at an intersection therebetween. The touch pin allows conduction to be established between the first and second touch panel interconnects when their intersection is located at the pressed position.
In the liquid crystal display panel, however, an alignment film for aligning liquid crystal molecules in the liquid crystal layer needs to be provided on a surface closer to the liquid crystal layer of each of the active matrix substrate and the counter substrate. The alignment films act as resistance components between the first and second touch panel interconnects, likely leading to malfunction of the touch panel.
By covering only the side surface of the touch pin, leaving the top portion of the touch pin exposed from the insulating film, in the matrix type resistive touch panel itself, not only the above-described malfunction of the touch panel due to the alignment films, but also an unwanted short circuit between the first and second touch panel interconnects due to, for example, foreign conductive particles, can be effectively reduced or prevented.
The present invention has been made in view of the above problems. It is an object of the present invention to ensure conduction at the top portion of the touch pin in the matrix type resistive touch panel.
To achieve the object, in the present invention, the first and second touch panel interconnects have a first touch pin and a second touch pin, respectively. Conduction is established between the first and second touch panel interconnects by the first touch pin and the second touch pin contacting each other.
Specifically, a liquid crystal display device according to the present invention includes an active matrix substrate including a plurality of first touch panel interconnects extending in parallel with each other, a counter substrate facing the active matrix substrate and including a plurality of second touch panel interconnects extending in parallel with each other in a direction intersecting the first touch panel interconnects, and a liquid crystal layer provided between the active matrix substrate and the counter substrate with an alignment film being interposed between the liquid crystal layer and each of the active matrix substrate and the counter substrate. The first touch panel interconnects each have a plurality of first touch pins having a columnar shape in regions where the first touch panel interconnects intersect the second touch panel interconnects. The second touch panel interconnects each have a plurality of second touch pins having a columnar shape in regions where the second touch panel interconnects intersect the first touch panel interconnects. When a surface of the active matrix substrate or the counter substrate is pressed, at least one of the first touch pins and a corresponding at least one of the second touch pins contact each other to establish conduction between the corresponding first and second touch panel interconnects.
With the above configuration, the first touch panel interconnects on the active matrix substrate intersect the second touch panel interconnects on the counter substrate with (the alignment film/)the liquid crystal layer(/the alignment film) being interposed therebetween. When a surface of the active matrix substrate or the counter substrate is pressed, conduction is established between at least one of the first touch panel interconnects and at least one of the second touch panel interconnects via at least one of the first touch pins provided on the first touch panel interconnects and a corresponding at least one of the second touch pins on the second touch panel interconnects. Therefore, a matrix type resistive touch panel is incorporated in a liquid crystal display device. Here, the columnar first and second touch pins (top portions thereof) protrude from surfaces of the active matrix substrate and the counter substrate, respectively, and therefore, are covered with the alignment films to a smaller extent than flat portions of the active matrix substrate and the counter substrate. In addition, the contact of the first and second touch pins establishes conduction between the first and second touch panel interconnects. Therefore, the alignment films act as lower resistance components between the first and second touch panel interconnects than when touch pins are provided on only one of the active matrix substrate and the counter substrate (for example, the first touch pins are provided on the active matrix substrate while the second touch pins are not provided on the counter substrate, and a surface portion of the counter substrate on which the top portion of the first touch pin is to abut is easily covered with the alignment film). Therefore, conduction can be reliably established at the top portions of the touch pins in the matrix type resistive touch panel incorporated in the liquid crystal display device.
The first touch pins or the second touch pins may each have a concave top portion.
With the above configuration, the first touch pins or the second touch pins each have a concave top portion, and therefore, a convex portion of an edge of the touch pin having the concave top portion acts as the fulcrum of a lever, thereby reducing or preventing a permanent short circuit which is caused by the first and second touch panel interconnects sticking to each other. Moreover, the contact area of the top portion increases, whereby conduction can be more reliably established at the top portions of the touch pins.
The first and second touch pins may be each formed in the shape of a line so that the first touch pins intersect the respective corresponding second touch pins.
With the above configuration, the first and second touch pins are each formed in the shape of a line so that the first touch pins intersect the respective corresponding second touch pins, and therefore, when the active matrix substrate and the counter substrate are joined with each other, then even if the substrates are deviated from each other, the first touch pin and the second touch pin can contact each other.
The active matrix substrate may include a plurality of first display interconnects extending in parallel with each other, and a plurality of second display interconnects extending in parallel with each other in a direction intersecting the first display interconnects. The first touch panel interconnects may be arranged along the respective corresponding first display interconnects, and the second touch panel interconnects may be arranged along the respective corresponding second display interconnects.
With the above configuration, the active matrix substrate includes a plurality of first display interconnects extending in parallel with each other, and a plurality of second display interconnects extending in parallel with each other in a direction intersecting the first display interconnects, the first touch panel interconnects are arranged along the respective corresponding first display interconnects, and the second touch panel interconnects are arranged along the respective corresponding second display interconnects. Therefore, an active matrix substrate including a plurality of gate lines extending in parallel with each other, a plurality of source lines extending in parallel with each other in a direction intersecting the gate lines, and first touch panel interconnects extending along the gate lines or the source lines, and a counter substrate including second touch panel interconnects, are specifically implemented.
A columnar photospacer configured to determine a thickness of the liquid crystal layer may be provided on the active matrix substrate or the counter substrate.
With the above configuration, the photospacer is interposed between the active matrix substrate and the counter substrate. When a surface of the active matrix substrate or the counter substrate is not pressed, the insulation between the first touch panel interconnects on the active matrix substrate and the second touch panel interconnects on the counter substrate can be maintained by the photospacer.
A touch panel according to the present invention includes a first substrate including a plurality of first touch panel interconnects extending in parallel with each other, a second substrate facing the first substrate and including a plurality of second touch panel interconnects extending in parallel with each other in a direction intersecting the first touch panel interconnects, and an intermediate layer provided between the first and second substrates with a protective film being interposed between the intermediate layer and each of the first and second substrates. The first touch panel interconnects each have a plurality of first touch pins having a columnar shape in regions where the first touch panel interconnects intersect the second touch panel interconnects. The second touch panel interconnects each have a plurality of second touch pins having a columnar shape in regions where the second touch panel interconnects intersect the first touch panel interconnects. When a surface of the first or second substrate is pressed, at least one of the first touch pins and a corresponding at least one of the second touch pins contact each other to establish conduction between the corresponding first and second touch panel interconnects.
With the above configuration, the first touch panel interconnects on the first substrate intersect the second touch panel interconnects on the second substrate with (the protective film/)the liquid crystal layer(/the protective film) being interposed therebetween. When a surface of the first substrate or the second substrate is pressed, conduction is established between at least one of the first touch panel interconnects and at least one of the second touch panel interconnects via at least one of the first touch pins provided on the first touch panel interconnects and a corresponding at least one of the second touch pins on the second touch panel interconnects. Therefore, a matrix type resistive touch panel is specifically implemented. Here, the columnar first and second touch pins (top portions thereof) protrude from surfaces of the first and second substrates, respectively, and therefore, are covered with the protective films to a smaller extent than flat portions of the first and second substrates. In addition, the contact of the first and second touch pins establishes conduction between the first and second touch panel interconnects. Therefore, the protective films act as lower resistance components between the first and second touch panel interconnects than when touch pins are provided on only one of the first and second substrates (for example, the first touch pins are provided on the first substrate while the second touch pins are not provided on the second substrate, and a surface portion of the second substrate on which the top portion of the first touch pin is to abut is easily covered with the protective film). Therefore, conduction can be reliably established at the top portions of the touch pins in the matrix type resistive touch panel. A display device according to the present invention includes the above touch panel and a display panel facing the touch panel.
With the above configuration, in the matrix type resistive touch panel, conduction is reliably established at the top portions of the touch pins. Therefore, the advantages of the present invention are effected in the display device including the touch panel outside the display panel.
According to the present invention, the first and second touch panel interconnects have a first touch pin and a second touch pin, respectively, and conduction is established between the first and second touch panel interconnects by the first touch pin and the second touch pin contacting each other. Therefore, in the matrix type resistive touch panel, conduction can be reliably established at the top portions of the touch pins.
Embodiments of the present invention will be described in detail hereinafter with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments below.
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As shown in FIGS. 1 and 3-5, the counter substrate 30a includes, for example, a black matrix B in the shape of a frame with a grid therein which is provided on an insulating substrate 10b, such as a glass substrate etc., and directly above the gate lines 11a (the first touch panel interconnects 19b) and the source lines 14a on the active matrix substrate 20a, a color filter 22 including a red color layer 22a, a green color layer 22b, and a blue color layer 22c provided in apertures of the black matrix B, a transparent layer 23a provided in the reflective regions R of the color filter 22 to compensate for optical path differences between the reflective regions R and the transparent regions T, a plurality of common electrodes 24a provided to cover BM lower layer portions 21a (described below) included in the black matrix B, the transparent regions T of the color filter 22, and the transparent layer 23a (the reflective regions R), a plurality of columnar photospacers 26 provided on the respective corresponding common electrodes 24a, and an alignment film 9b provided to cover the common electrodes 24a, a portion of each BM upper layer portion 25a (a portion other than second touch pins Pb described below) included in the black matrix B, and the photospacers 26.
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The BM lower layer portion 21a is made of a resin, e.g., an organic insulating film in which a black pigment is dispersed.
The BM upper layer portion 25a is made of a light-shielding metal film, such as a chromium film etc., and has conductivity. As shown in
Here, the first touch pin Pa and the second touch pin Pb may be, for example, formed in the shape of a cylinder as shown in
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The liquid crystal layer 40 is made of a nematic liquid crystal material having electro-optic characteristics, etc.
The semi-transmissive liquid crystal display device 50a thus configured is arranged so that light entering through the counter substrate 30a is reflected from the reflective electrode 18a in the reflective region R, while light from a backlight entering through the active matrix substrate 20a is transmitted in the transparent region T.
The liquid crystal display device 50a displays an image in the following manner. In each pixel, a gate signal is transferred from the gate line 11 to the gate electrode 11a, so that the TFT 5 is turned on. Thereafter, a source signal is transferred from the source line 14a to the source electrode (14a). As a result, predetermined charge is written via the semiconductor layer 13 and the drain electrode 14b to the pixel electrode 19a including the transparent electrode 17a and the reflective electrode 18a. In this case, in the liquid crystal display device 50a, a potential difference occurs between the pixel electrode 19a of the active matrix substrate 20a and the corresponding common electrode 24a of the counter substrate 30a, so that a predetermined voltage is applied to the liquid crystal layer 40. In the liquid crystal display device 50a, the alignment of the liquid crystal layer 40 is changed, depending on the magnitude of the voltage applied to the liquid crystal layer 40, to adjust the light transmittance of the liquid crystal layer 40, thereby displaying an image.
Also, in the liquid crystal display device 50a, when a surface of the active matrix substrate 20a or the counter substrate 30a is pressed, the first touch pin Pa of the first touch panel interconnect 19b and the second touch pin Pb of the BM upper layer portion 25a (second touch panel interconnect) contact each other to establish conduction, whereby a pressed (touch) position is detected.
Next, an example method of manufacturing the liquid crystal display device 50a of this embodiment will be described. Note that the manufacturing method of this embodiment includes an active matrix substrate fabricating step, a counter substrate fabricating step, and a substrate joining step.
<Active Matrix Substrate Fabricating Step>
Initially, for example, a titanium film, an aluminum film, and a titanium film, etc. are successively formed by sputtering on an entirety of the insulating substrate 10a, such as a glass substrate etc. Thereafter, patterning is performed by photolithography to form the gate lines 11 and the gate electrodes 11a having a thickness of about 4,000 Å.
Next, for example, a silicon nitride film etc. is formed by plasma-enhanced chemical vapor deposition (CVD) on an entirety of the substrate on which the gate lines 11 and the gate electrodes 11a have been formed, thereby forming the gate insulating film 12 having a thickness of about 4,000 Å.
Next, for example, an intrinsic amorphous silicon film (thickness: about 2,000 Å) and a phosphorus-doped n+ amorphous silicon film (thickness: about 500 Å) are successively formed by plasma-enhanced CVD on an entirety of the substrate on which the gate insulating film 12 has been formed. Thereafter, patterning is performed by photolithography to form on each of the gate electrodes (11a) an island-like pattern of a semiconductor layer formation layer in which the intrinsic amorphous silicon layer and the n+ amorphous silicon layer are stacked.
Thereafter, for example, an aluminum film and a titanium film, etc. are successively formed by sputtering on an entirety of the substrate on which the semiconductor layer formation layer has been formed. Thereafter, patterning is performed by photolithography to form the source lines 14a, the source electrodes (14a), and the drain electrodes 14b having a thickness of about 2,000 Å.
Next, the n+ amorphous silicon layer of the semiconductor layer formation layer is etched using the source electrodes (14a) and the drain electrodes 14b as a mask to form channel regions by patterning, thereby forming the semiconductor layer 13 and the TFTs 5 including the semiconductor layer 13.
Moreover, for example, a silicon nitride film etc. is formed by plasma-enhanced CVD on an entirety of the substrate on which the TFTs 5 have been formed, thereby forming the first interlayer insulating film 15 having a thickness of about 4,000 Å.
Thereafter, for example, a positive photosensitive resin having a thickness of about 3 μm is applied by spin coating onto an entirety of the substrate on which the first interlayer insulating film 15 has been formed. The applied photosensitive resin is uniformly exposed to relatively low illuminance using a first photomask in which a plurality of circular light shielding portions are separately and randomly formed, and then uniformly exposed to relatively high illuminance using a second photomask in which openings are formed at positions corresponding to the contact holes 16c on the drain electrodes 14b, followed by development. As a result, the portions exposed to the high illuminance of the photosensitive resin are completely removed, while the portions exposed to the low illuminance of the photosensitive resin are left with a thickness of about 40% of the applied thickness. The unexposed portions of the photosensitive resin are left with a thickness of about 80% of the applied thickness. Moreover, the substrate with the developed photosensitive resin is heated to about 200° C., to melt the photosensitive resin, thereby forming the second interlayer insulating film 16 having a smooth and corrugated surface in each reflective region R and a convex surface in each region where the first touch pin Pa is to be formed. Thereafter, the first interlayer insulating film 15 exposed from the second interlayer insulating film 16 is etched to form the contact holes 16c.
Next, a transparent conductive film made of an indium tin oxide (ITO) film etc. is formed by sputtering on an entirety of the substrate on which the second interlayer insulating film 16 has been formed. Thereafter, patterning is performed by photolithography to form the transparent electrodes 17a and the transparent conductive layer 17b having a thickness of about 1,000 Å.
Moreover, a molybdenum film (thickness: about 750 Å) and an aluminum film (thickness: about 1,000 Å) are successively formed by sputtering on an entirety of the substrate on which the transparent electrodes 17a and the transparent conductive layer 17b have been formed. Thereafter, patterning is performed by photolithography to form the reflective electrodes 18a and the reflective conductive layer 18b. As a result, the pixel electrodes 19a including the transparent electrodes 17a and the reflective electrodes 18a, and the first touch panel interconnects 19b including the transparent conductive layer 17b and the reflective conductive layer 18b, are formed.
Finally, a polyimide resin is applied by a printing technique onto an entirety of the substrate on which the pixel electrodes 19a and the first touch panel interconnects 19b have been formed. Thereafter, a rubbing treatment is performed to form the alignment film 9a having a thickness of about 1,000 Å.
Thus, the active matrix substrate 20a can be fabricated.
<Counter Substrate Fabricating Step>
Initially, for example, an acrylic photosensitive resin in which a black pigment, such as carbon particles etc., is dispersed is applied by spin coating onto an entirety of the insulating substrate 10b, such as a glass substrate etc. The applied photosensitive resin is exposed using a photomask and then developed to perform patterning, thereby forming the BM lower layer portions 21a having a thickness of about 2.0 μm.
Next, an acrylic photosensitive resin is applied by spin coating onto an entirety of the substrate on which the BM lower layer portions 21a have been formed. The applied photosensitive resin is exposed using a photomask and then developed and heated to form the resin layer 23b having a thickness of about 2.0 μm.
Moreover, for example, a chromium film is formed by sputtering on an entirety of the substrate on which the resin layer 23b has been formed. Thereafter, patterning is performed by photolithography to form the BM upper layer portions 25a having a thickness of about 2,000 Å.
Next, for example, a red-, green-, or blue-colored acrylic photosensitive resin is applied onto the substrate on which the BM upper layer portions 25a have been formed. The applied photosensitive resin is exposed using a photomask and then developed to perform patterning, thereby forming a color layer with a selected color (for example, the red color layer 22a) having a thickness of about 2.0 μm. Moreover, by repeating a similar process for the two other colors, color layers with the two other colors (for example, the green color layer 22b and the blue color layer 22c) having a thickness of about 2.0 μm are formed. As a result, the color filter 22 including the red color layer 22a, the green color layer 22b, and the blue color layer 22c is formed.
Moreover, an acrylic photosensitive resin is applied by spin coating onto the substrate on which the color filter 22 has been formed. The applied photosensitive resin is exposed using a photomask and then developed to form the transparent layer 23a having a thickness of about 2 μm.
Thereafter, for example, an ITO film is formed by sputtering on an entirety of the substrate on which the transparent layer 23a has been formed. Thereafter, patterning is performed by photolithography to form the common electrodes 24a having a thickness of about 1,500 Å.
Moreover, an acrylic photosensitive resin is applied by spin coating onto an entirety of the substrate on which the common electrodes 24a have been formed. The applied photosensitive resin is exposed using a photomask and then developed to form the photospacers 26 having a thickness of about 4 μm.
Finally, a polyimide resin is applied by a printing technique onto an entirety of the substrate on which the photospacers 26 have been formed. Thereafter, a rubbing treatment is performed to form the alignment film 9b having a thickness of about 1,000 Å.
Thus, the counter substrate 30a can be fabricated.
<Substrate Joining Step>
Initially, for example, a frame-like sealing member made of an ultraviolet and thermal curing resin etc. is applied (drawn), using a dispenser, onto the counter substrate 30a which has been fabricated in the counter substrate fabricating step.
Next, a liquid crystal material is dropped into a region inside the sealing member of the counter substrate 30a on which the sealing member has been applied (drawn).
Moreover, the counter substrate 30a on which the liquid crystal material has been dropped, and the active matrix substrate 20a which has been formed in the active matrix substrate fabricating step, are joined with each other under reduced pressure. The counter substrate 30a and the active matrix substrate 20a thus joined with each other are exposed to the atmosphere so that pressure is applied on the outer surfaces of the counter substrate 30a and the active matrix substrate 20a.
Finally, the sealing member interposed between the counter substrate 30a and the active matrix substrate 20a which have been joined with each other is irradiated with UV light and then heated, whereby the sealing member is cured.
Thus, the liquid crystal display device 50a can be fabricated.
As described above, according to the liquid crystal display device 50a of this embodiment, the first touch panel interconnects 19b on the active matrix substrate 20a and the BM upper layer portions 25a serving as the second touch panel interconnects on the counter substrate 30a intersect with the alignment film 9a/the liquid crystal layer 40/the alignment film 9b being interposed therebetween. When a surface of the active matrix substrate 20a or the counter substrate 30a is pressed, conduction is established between at least one of the first touch panel interconnects 19b and at least one of the BM upper layer portions 25a via at least one of the first touch pins Pa provided on the first touch panel interconnects 19b and at least one of the second touch pins Pb provided on the BM upper layer portions 25a. Thus, a matrix type resistive touch panel is incorporated in a liquid crystal display device. Here, top portions of the columnar first and second touch pins Pa and Pb protrude from surfaces of the active matrix substrate 20a and the counter substrate 30a, respectively, and therefore, are covered with the alignment films 9a and 9b to a smaller extent than flat portions of the active matrix substrate 20a and the counter substrate 30a. In addition, the contact of the first and second touch pins Pa and Pb establishes conduction between the first touch panel interconnect 19b and the BM upper layer portion 25a. Therefore, the alignment films 9a and 9b act as lower resistance components between the first touch panel interconnect 19b and the BM upper layer portion 25a than when touch pins are provided on only one of the active matrix substrate and the counter substrate (for example, a liquid crystal display device 150 as shown in
Also, according to the liquid crystal display device 50a of this embodiment, the photospacers 26 are interposed between the active matrix substrate 20a and the counter substrate 30a. Therefore, when a surface of the active matrix substrate 20a or the counter substrate 30a is not pressed, the insulation between the first touch panel interconnects 19b on the active matrix substrate 20a and the BM upper layer portions 25a on the counter substrate 30a can be maintained by the photospacers 26.
While the first display interconnects are gate lines and the second display interconnects are source lines in the liquid crystal display device 50a of the first embodiment, the first display interconnects are source lines and the second display interconnects are gate lines in the liquid crystal display device 50b of this embodiment.
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The BM lower layer portion 21b is made of a resin, e.g., an organic insulating film in which a black pigment is dispersed.
The BM upper layer portion 25b is made of a light-shielding metal film, such as a chromium film etc., and has conductivity. Here, as shown in
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The semi-transmissive liquid crystal display device 50b thus configured is arranged so that light entering through the counter substrate 30b is reflected from the reflective electrode 18a in the reflective region R, while light from a backlight entering through the active matrix substrate 20b is transmitted in the transparent region T.
The liquid crystal display device 50b displays an image in the following manner. In each pixel, a gate signal is transferred from the gate line 11 to the gate electrode 11a, so that the TFT 5 is turned on. Thereafter, a source signal is transferred from the source line 14a to the source electrode (14a). As a result, predetermined charge is written via the semiconductor layer 13 and the drain electrode 14b to the pixel electrode 19a including the transparent electrode 17a and the reflective electrode 18a. In this case, in the liquid crystal display device 50b, a potential difference occurs between the pixel electrode 19a of the active matrix substrate 20b and the corresponding common electrode 24b of the counter substrate 30b, so that a predetermined voltage is applied to the liquid crystal layer 40. In the liquid crystal display device 50b, the alignment of the liquid crystal layer 40 is changed, depending on the magnitude of the voltage applied to the liquid crystal layer 40, to adjust the light transmittance of the liquid crystal layer 40, thereby displaying an image.
Also, in the liquid crystal display device 50b, when a surface of the active matrix substrate 20b or the counter substrate 30b is pressed, the first touch pin Pa of the first touch panel interconnect 19c and the second touch pin Pb of the BM upper layer portion 25b (second touch panel interconnect) contact each other to establish conduction, whereby a pressed (touch) position is detected.
Note that the liquid crystal display device 50b of this embodiment can be fabricated by the active matrix fabricating step and the counter substrate fabricating step described in the first embodiment where the patterns of the constituent thin films are changed.
As described above, according to the liquid crystal display device 50b of this embodiment, as in the first embodiment, the alignment films 9a and 9b do not act as resistance components between the first touch panel interconnect 19c and the BM upper layer portion 25b. As a result, conduction can be reliably established at the top portions of the touch pins in the matrix type resistive touch panel incorporated in the liquid crystal display device.
While a matrix type resistive touch panel is incorporated in the liquid crystal display device of each of the above embodiments, a matrix type resistive touch panel 60 is mounted on a front surface of a liquid crystal display panel 50 in the liquid crystal display device 70 of this embodiment.
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The active matrix substrate 20 includes, for example, a plurality of gate lines (not shown) provided on an insulating substrate (not shown), such as a glass substrate etc., extending in parallel with each other, a gate insulating film (not shown) provided to cover the gate lines, a plurality of source lines (not shown) provided on the gate insulating film, extending in parallel with each other in a direction perpendicular to the gate lines, a plurality of TFTs (not shown) each provided at a corresponding one of intersections of the gate lines and the source lines, interlayer insulating films (not shown) successively provided to cover the source lines and the TFTs, a plurality of pixel electrodes (not shown) arranged in a matrix on the interlayer insulating films and connected to the respective corresponding TFTs, and an alignment film (not shown) provided to cover the pixel electrodes.
The counter substrate 30 includes, for example, a black matrix (not shown) in the shape of a frame with a grid therein which is provided on an insulating substrate (not shown), such as a glass substrate etc., and directly above the gate lines and the source lines on the active matrix substrate 20, a color filter (not shown) provided in apertures of the black matrix, a common electrode (not shown) provided to cover the black matrix and the color filter, columnar photospacers (not shown) provided on the common electrode, and an alignment film (not shown) provided to cover the common electrode and the photospacers.
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In the touch panel 60, when a surface of the second substrate 66 is pressed, the first touch pin Pa of the first touch panel interconnect 62 and the second touch pin Pb of the second touch panel interconnect 68 contact each other to establish conduction, whereby a pressed (touch) position is detected.
According to the touch panel 60 of this embodiment and the liquid crystal display device 70 including the touch panel 60, the first touch panel interconnects 62 on the first substrate 61 and the second touch panel interconnects 68 on the second substrate 66 intersect with the protective film 64a/the air layer 65/the protective film 64b being interposed therebetween. When a surface of the second substrate 66 is pressed, conduction is established between at least one of the first touch panel interconnects 62 and at least one of the second touch panel interconnects 68 via at least one of the first touch pins Pa provided on the first touch panel interconnects 62 and at least one of the second touch pins Pb provided on the second touch panel interconnects 68. Thus, a matrix type resistive touch panel is specifically implemented. Here, top portions of the columnar first and second touch pins Pa and Pb protrude from surfaces of the first and second substrates 61 and 66, respectively, and therefore, are covered with the protective films 64a and 64b to a smaller extent than flat portions of the first and second substrates 61 and 62. In addition, the contact of the first and second touch pins Pa and Pb establishes conduction between the first and second touch panel interconnects 62 and 68. Therefore, the protective films 64a and 64b act as lower resistance components between the first and second touch panel interconnects 62 and 68 than when touch pins are provided on only one of the first and second substrates (for example, first pins are provided on the first substrate while no second pins are provided on the second substrate, and therefore, a surface portion of the second substrate on which the top portion of the touch pin abuts when pressed is easily covered with a protective film). Therefore, conduction can be reliably established at the top portions of the touch pins in the matrix type resistive touch panel.
In this embodiment, an active matrix drive type liquid crystal display panel has been illustrated as the display panel of the present invention. Alternatively, the present invention is applicable to other display panels, such as a passive matrix drive type liquid crystal display panel, an active matrix drive type or passive matrix drive type organic electro luminescence (EL) display panel, etc.
While the first and second touch pins Pa and Pb having a columnar shape have been illustrated in the above embodiments, the first touch pin Pa or the second touch pin Pb has a concave top portion in this embodiment.
Specifically, as shown in
According to the liquid crystal display device of this embodiment, as in the first and second embodiments, the alignment films do not act as resistance components between the first and second touch panel interconnects. Therefore, conduction can be reliably established at the top portions of the touch pins in the matrix type resistive touch panel incorporated in the liquid crystal display device.
According to the liquid crystal display device of this embodiment, the first touch pin Pa has the concave top portion, and therefore, a convex portion of an edge of the first touch pin Pa having the concave top portion acts as the fulcrum of a lever, thereby reducing or preventing a permanent short circuit which is caused by the first and second touch panel interconnects sticking to each other.
While the first touch pin Pa and the second touch pin Pb included in the touch panel incorporated in the liquid crystal display device have been illustrated in this embodiment, the present invention is also applicable to first and second touch pins in a touch panel when it is used singly.
In the first to third embodiments, the first and second touch pins Pa and Pb whose top portions are positioned directly above each other have been illustrated. Alternatively, in this embodiment, the first and second touch pins Pa and Pb intersect each other.
Specifically, as shown in
According to the liquid crystal display device of this embodiment, as in the first, second, and fourth embodiments, the alignment films do not act as resistance components between the first and second touch panel interconnects. Therefore, conduction can be reliably established at the top portions of the touch pins in the matrix type resistive touch panel incorporated in the liquid crystal display device.
Also, according to the liquid crystal display device of this embodiment, the first touch pin Pa and the second touch pin Pb are formed in the shape of lines intersecting each other. Therefore, when the active matrix substrate and the counter substrate are joined with each other, then even if the substrates are deviated from each other, the first touch pin Pa and the second touch pin Pb can contact each other.
While the first touch pin Pa and the second touch pin Pb included in the touch panel incorporated in the liquid crystal display device have been illustrated in this embodiment, the present invention is also applicable to first and second touch pins in a touch panel when it is used singly.
While one touch panel interconnect is provided for each display interconnect (a gate line or a source line) in the first and second embodiments, the present invention may also be applicable when one touch panel interconnect is provided for a plurality of adjacent display interconnects, i.e., the touch panel interconnects may be thinned out to reduce the number thereof.
While the first touch panel interconnects and the pixel electrodes 19a are simultaneously formed in the first and second embodiments, the first touch panel interconnects may be formed at the same time when the gate lines or the source lines are formed in the present invention.
While a semi-transmissive liquid crystal display device has been illustrated in the above embodiments, the present invention may be applicable to a transmissive or reflective liquid crystal display device.
While a single-touch touch panel has been illustrated in the above embodiments, the present invention may be applicable to a multi-touch touch panel.
The liquid crystal display devices of the above embodiments may be any of the following types: twisted nematic (TN); vertical alignment (VA); multi-domain vertical alignment (MVA); advanced super view (ASV); in-plane-switching (IPS); etc.
As described above, the present invention can provide a thinner and lighter liquid crystal display device including a resistive touch panel, and therefore, is useful for automotive navigation systems, personal digital assistants (PDAs), etc., and more particularly, for any kind of mobile device, such as mobile telephones, notebook personal computers, hand-held game devices, digital cameras, etc.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2008-242411 | Sep 2008 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2009/002763 | 6/17/2009 | WO | 00 | 3/10/2011 |
