Patent Application
20130293801
The present invention relates to a display panel and a display device provided with the same.
Conventionally, as a display device, a liquid crystal display device that conducts display by relying on changes in optical properties of liquid crystal is known (refer to Patent Document 1, for example).
Normally, in a conventional liquid crystal display device, two substrates are disposed facing each other, and a liquid crystal layer is sandwiched between the two substrates.
As a specific configuration, on a prescribed surface of one of the two substrates, TFTs (thin film transistors) connected to pixel electrodes, an interlayer insulating film (organic film) covering the TFTs, and the like are formed. On a prescribed surface of the other of the two substrates, a black matrix layer (organic film) functioning as a light-shielding layer, an opposite electrode (ITO film) that generates an electric field between the opposite electrode and the pixel electrodes, and the like are formed. The two substrates are bonded together with a sealing member such that the respective prescribed surfaces of the substrates face each other.
The sealing member that bonds together the two substrates is disposed between the two substrates along the outer edge of a display region so as to surround the display region. The liquid crystal layer sandwiched between the two substrates is sealed inside the display region by the sealing member.
Patent Document 1: Japanese Patent Application Laid-Open Publication No. 2009-180915
In the above-mentioned conventional configuration, there are cases in which a sealing member is disposed between an interlayer insulating film provided on one substrate and an opposite electrode provided on the other substrate, and the two substrates are bonded to each other by bonding the interlayer insulating film and the opposite electrode to each other with the sealing member. In such a case, the adhesion between the interlayer insulating film and the sealing member is not very strong, and the adhesion between the opposite electrode and the sealing member is also not very strong, and as a result, the adhesive strength between the two substrates is low. In other words, the two substrates are susceptible to detachment from each other, which causes defects such as liquid crystal leaking out from between the two substrates, for example.
The present invention was made in order to solve the above mentioned problem, and an object thereof is to provide a display panel in which the adhesive strength between the two substrates can be increased, and a display device provided therewith.
In order to achieve the above-mentioned object, a display panel according to a first aspect of the present invention includes: a first substrate having a first surface, the first surface having formed thereon switching elements connected to pixel electrodes and an insulating film covering the switching elements; a second substrate having a second surface facing the first surface, the second surface having formed thereon a black matrix layer as a light-shielding layer and an opposite electrode that generates an electric field between the opposite electrode and the pixel electrodes; and a sealing member disposed between the first substrate and the second substrate along an outer periphery of the second substrate that includes a corner thereof, the sealing member bonding together the first substrate and the second substrate. A cut-out is formed in a portion of the insulating film corresponding in position to the corner of the second substrate, and cut-outs are respectively formed in a portion of the black matrix layer at the corner of the second substrate and a portion of the opposite electrode at the corner of the second substrate.
In the display panel of the first aspect, as described above, when disposing a sealing member (member for bonding together the first substrate and the second substrate) between the first substrate and the second substrate along the outer periphery of the second substrate including the corners thereof, cut-outs are formed in portions of the insulating film (film formed on the first surface of the first substrate) corresponding in position to the corners of the second substrate, thus exposing prescribed portions of the first surface of the first substrate (portions thereof overlapping portions of the sealing member) corresponding in position to the corners of the second substrate, and it is possible to have the sealing member directly bonded to the prescribed portions of the first surface of the first substrate. In addition, cut-outs are formed in portions of the black matrix layer at the corners of the second substrate, and portions of the opposite electrode at the corners of the second substrate, and thus, the corners (portions overlapping portions of the sealing member) of the second surface of the second substrate are also exposed. Thus, it is possible to also directly bond the sealing member to the corners of the second surface of the second substrate. As a result, the adhesive strength between the first substrate and the second substrate is increased.
If the adhesive strength between the first substrate and the second substrate can be increased, then it is possible to mitigate a leakage of the liquid crystal layer from between the first substrate and the second substrate if a liquid crystal layer is disposed between the first substrate and the second substrate.
If normally unnecessary cut-outs are formed in the black matrix layer, light leaks therethrough, which sometimes has a negative visual effect. However, in the display panel of the first aspect, cut-outs are formed in portions of the black matrix layer at the corners of the second substrate (in other words, portions at the vicinity of the corners of the display region), and thus, there is not much negative visual effect.
In the display panel according to the first aspect, it is preferable that when the second substrate has a plurality of corners, the cut-out be formed in every portion of the insulating film corresponding in position to each of the plurality of corners of the second substrate, and that the cut-out be formed in every portion of the black matrix layer positioned at each of the plurality of corners of the second substrate, and in every portion of the opposite electrode positioned at each of the plurality of corners of the second substrate. With this configuration, the area in which the sealing member is directly bonded to the first surface of the first substrate is increased, and the area in which the sealing member is directly bonded to the second surface of the second substrate is also increased. Therefore, the adhesive strength between the first substrate and the second substrate is further increased.
It is preferable that the display panel according to the first aspect further include pad electrodes disposed on the insulating film, the pad electrodes supplying an electrical signal to the opposite electrode, wherein the pad electrodes are disposed on portions of the insulating film other than the portion where the cut-out is formed. With this configuration, prescribed portions of the first surface of the first substrate (portions where the sealing member is to be directly bonded) are not blocked by the pad electrodes. Thus, even in a configuration in which the pad electrodes are formed on the insulating film, the sealing member can be directly bonded onto prescribed portions of the first surface of the first substrate with ease.
In a configuration in which the pad electrodes are formed on the insulating film, when a common wiring line connected to the pad electrodes is formed on the first surface of the first substrate, it is preferable that the common wiring line be drawn so as to avoid the portion of the first surface of the first substrate corresponding in position to the corner of the second substrate. With this configuration, prescribed portions of the first surface of the first substrate (portions where the sealing member is to be directly bonded) are not blocked by the common wiring line. Thus, even in a configuration in which the common wiring line is formed on the first surface of the first substrate, the sealing member can be directly bonded onto prescribed portions of the first surface of the first substrate with ease.
In the display panel according to the first aspect, it is preferable that the cut-out be formed in a portion of the outer periphery of the black matrix layer surrounding a display region, and that a minimum distance from an edge of the outer periphery of the black matrix layer to the display region in a portion where the cut-out is formed be no less than a minimum distance from an edge of the outer periphery of the black matrix layer to the display region in a portion where the cut-out is not formed.
In the display panel according to the first aspect, among the cut-out of the insulating film, the cut-out of the black matrix layer, and the cut-out of the opposite electrode, at least two thereof may be the same shape.
A display device according to a second aspect of the present invention includes the display panel according to the first aspect. With a display device configured in this manner, the adhesive strength between the first substrate and the second substrate can be increased.
As stated above, according to the present invention, it is possible to obtain with ease a display panel and a display device in which the adhesive strength between the first substrate and the second substrate can be increased.
A display device according to an embodiment of the present invention will be described with reference to
The display device of the present embodiment is a liquid crystal display device, and as shown in
The liquid crystal display panel 10 has a display region (rectangular region in
The respective plurality of subpixels P correspond to any of the following colors: red (R), green (G), and blue (B). A collection that includes one each of a red (R) subpixel P, a green (G) subpixel P, and a blue (B) subpixel P constitutes one pixel.
Each of the plurality of subpixels P has a circuit configuration as shown in
The switching elements 11 are constituted of TFTs (thin film transistors), and the gate of each switching element 11 is connected to a gate line (scanning line) GL, and the source of each switching element 11 is connected to a source line (data line) SL. The pixel electrode 12 is connected to the drain of the switching element 11, and the opposite electrode 13 is disposed facing the pixel electrodes 12. A liquid crystal layer LC is sandwiched between the pixel electrodes 12 and the opposite electrode 13. A switching element 11 is provided individually for each subpixel P, and a pixel electrode 12 is provided individually for each subpixel P. On the other hand, the opposite electrode 13 is common to all subpixels P.
The backlight unit BL shown in
When conducting display, the optical properties (light transmittance) are individually changed for each of the plurality of subpixels P formed in the liquid crystal display panel 10 based on an image signal. Specifically, at each subpixel P (refer to
Thus, when the liquid crystal display panel 10 is illuminated from the rear by backlight from the backlight unit BL, the transmittance of the backlight through the liquid crystal display panel 10 differs for each subpixel P, and as a result, a desired image is displayed in the display region A of the liquid crystal display panel 10.
The configuration of the liquid crystal display panel 10 is described in more detail below.
The liquid crystal display panel 10 includes at least two glass substrates (transparent substrates) 1 and 2. One glass substrate 1 is an example of the “first substrate” of the present invention, and the other glass substrate 2 is an example of the “second substrate” of the present invention. The one glass substrate 1 is sometimes referred to as a TFT substrate or an active matrix substrate. The other glass substrate 2 is sometimes referred to as an opposite substrate or a color filter substrate (CF substrate).
As shown in
The two glass substrates 1 and 2 differ in outer shape size; the outer shape size of the glass substrate 1 is greater than the outer shape size of the glass substrate 2. Therefore, as shown in
Returning to
A source electrode S and a drain electrode D are formed on the switching element 11. The source electrode S is connected to the source region of the semiconductor layer 11c, and the drain electrode D is connected to the drain region of the semiconductor layer 11c.
The switching element 11, the source electrode S, and the drain electrode D are covered by an interlayer insulating film (an organic film made of a material such as a photosensitive acrylic resin) 14. All portions of the interlayer insulating film 14 cover the gate insulating film 11b. In other words, the interlayer insulating film 14 covers most (but not all) of the region of the prescribed surface 1a of the glass substrate 1 covered by the glass substrate 2, through the gate insulating film 11b.
Returning to
Although not shown in
A black matrix layer (light-shielding layer) 17 is formed on the prescribed surface 2a of the other glass substrate 2. The black matrix layer 17 is disposed so as to surround regions corresponding to the respective red (R), green (G), and blue (B) subpixels P. In other words, the black matrix layer 17 divides the regions corresponding to the respective red (R), green (G), and blue (B) subpixels P. The outer periphery (frame portion) of the black matrix layer 17 is formed in a shape following the outer periphery of the glass substrate 2, and is disposed along the outer periphery of the glass substrate 2, and thus, the outer periphery of the black matrix layer 17 surrounds the display region A.
Returning to
The opposite electrode 13 is formed on a surface of the color filter layer 18 opposite to the glass substrate 2, and covers most (but not all) of the prescribed surface 2a of the glass substrate 2.
Returning to
Additionally, although not shown in drawings, the surface of the glass substrate 1 opposite to the prescribed surface 1a and the surface of the glass substrate 2 opposite to the prescribed surface 2a are each provided with one polarizing sheet that only transmits light waves oscillating in a specific direction. The respective transmission axes of the polarizing sheet on the glass substrate 1 and the polarizing sheet on the glass substrate 2 are at approximately 90° with respect to each other.
The two glass substrates 1 and 2 are bonded together such that a sealing member 3 (refer to
As shown in
As shown in
As shown in
Additionally, as shown in
In the present embodiment, as shown in
In the present embodiment, of the cut-outs 14b of the interlayer insulating film 14, the cut-outs 17b of the black matrix layer 17, and the cut-outs 13b of the opposite electrode 13, the cut-outs 14b of the interlayer insulating film 14 and the cut-outs 13b of the opposite electrode 13 are the same shape. However, the configuration is not limited thereto, and a configuration may be used in which the cut-outs 14b of the interlayer insulating film 14, the cut-outs 17b of the black matrix layer 17, and the cut-outs 13b of the opposite electrode 13 are all given different shapes, or in which the cut-outs 14b of the interlayer insulating film 14, the cut-outs 17b of the black matrix layer 17, and the cut-outs 13b of the opposite electrode 13 all have the same shape.
The fact that the common wiring line 15 (refer to
In order for the pad electrodes 16 (common wiring line 15) to supply an electrical signal to the opposite electrode 13 through the sealing member 3, in the present embodiment, the sealing member 3 is made electrically conductive by mixing conductive particles (elastic bodies coated in gold or silver, for example) into the sealing member 3. The pad electrodes 16 (common wiring line 15) overlap the sealing member 3 and the opposite electrode 13. As a result, when an electrical signal is inputted into the pad electrodes 16 from the common wiring line 15, this electrical signal is transmitted to the opposite electrode 13 through the sealing member 3.
However, because in the present embodiment the four portions (four portions respectively corresponding in position to the four corners 2b of the glass substrate 2) 1b of the prescribed surface 1a of the glass substrate 1 are exposed, as shown in
As shown in
In the present embodiment, as described above, by forming cut-outs 14b in portions 14a of the interlayer insulating film (film formed on the prescribed surface 1a of the glass substrate 1) 14 that correspond in position to the corners 2b of the glass substrate 2, portions (portions overlapping portions of the sealing member 3) 1b of the prescribed surface 1a of the glass substrate 1 that correspond in position to the corners 2b of the glass substrate 2 are exposed, and thus, the sealing member 3 can be directly bonded to the portions 1b of the prescribed surface 1a of the glass substrate 1. In addition, cut-outs 17b are also formed in the portions 17a of the black matrix layer 17 at the corners 2b of the glass substrate 2 and cut-outs 13b are also formed in portions 13a of the opposite electrode 13 at the corners 2b of the glass substrate 2, and thus, the corners (portions overlapping portions of the sealing member 3) 2b of the prescribed surface 2a of the glass substrate 2 are also exposed. Thus, the sealing member 3 can be directly bonded to the corners 2b of the prescribed surface 2a of the glass substrate 2. As a result, the adhesive strength between the glass substrate 1 and the glass substrate 2 is increased.
If the adhesive strength between the glass substrate 1 and the glass substrate 2 can be increased, then leakage of the liquid crystal layer LC from between the glass substrate 1 and the glass substrate 2 can be mitigated.
If normally unnecessary cut-outs (openings) are formed in the black matrix layer 17, then there is a risk that light would leak through, causing a negative visual effect. However, in the present embodiment, cut-outs 17b are formed in portions of the black matrix layer 17 at the corners 2b of the glass substrate 2 (in other words, portions in the vicinity of the corners of the display region A), and thus there is not much effect visually.
Also, in the present embodiment, as described above, the four portions 1b of the prescribed surface 1a of the glass substrate 1 are exposed, and the sealing member 3 is directly bonded to all four portions 1b, and thus, the area in which the sealing member 3 is directly bonded to the prescribed surface 1a of the glass substrate 1 is increased. The four corners 2b of the prescribed surface 2a of the glass substrate 2 are exposed and the sealing member 3 is directly bonded to all four corners 2b, and thus, the area in which the sealing member 3 is directly bonded to the prescribed surface 2a of the glass substrate 2 is also increased. Therefore, the adhesive strength between the glass substrate 1 and the glass substrate 2 is further increased.
In the present embodiment, as stated above, the pad electrodes 16 are disposed in portions other than the four portions (portions where the cut-outs 14b are formed) 14a of the interlayer insulating film 14, and thus, the four portions (portions where the sealing member 3 is to be directly bonded) 1b of the prescribed surface 1a of the glass substrate 1 are not blocked by the pad electrodes 16. In addition, the common wiring line 15 is drawn so as to avoid the four portions 1b of the prescribed surface 1a of the glass substrate 1, and thus, the four portions 1b of the prescribed surface 1a of the glass substrate 1 are not blocked by the common wiring line 15. As a result, the sealing member 3 can be directly bonded to the four portions 1b of the prescribed surface 1a of the glass substrate 1 with ease.
In the embodiment above, a configuration may be used in which instead of the sealing member 3 being bonded to the prescribed surface 1a of the glass substrate 1, a surface of the gate insulating film 11b is exposed and the sealing member 3 is bonded onto the surface of the gate insulating film 11b as shown in
In the configuration of the embodiment above, the shape of the cut-outs 14b of the interlayer insulating film 14 may be modified. For example, as shown in
In the configuration of the embodiment above, modifications in shape shown in
As shown in
However, in a method in which a metal mask is used, there are limits on how narrow the mask can be made when taking the strength thereof into account, and patterning cannot be conducted in a precise manner. For example, while it is possible to set the width of the mask at approximately 3 mm, if this is done, unnecessarily wide spaces are formed between adjacent ITO layers 21, which decreases the number of opposite substrates that can be obtained from one mother glass 20. In addition, a step of removing extra regions (a separation step, for example) is necessary.
As a countermeasure, when manufacturing a narrow frame liquid crystal display panel (a liquid crystal display panel in which the distance from the edge thereof to the display region is 2 mm or less, for example), a configuration may be used in which the opposite substrate is manufactured using photolithography, which is widely known as a manufacturing method for the TFT substrate. In other words, when forming the opposite electrode on the mother glass 20, the ITO layer 21 on the mother glass 20 simply needs to be patterned using photolithography. As a result, a narrow frame liquid crystal display panel can be obtained with ease.
The embodiment disclosed herein is an example in every respect and is not limiting. The scope of the present invention is shown in the claims and not the embodiment described above, and in addition, all modifications within the equivalent meaning and scope of the claims are included.
1 glass substrate (first substrate)
1
a prescribed surface (first surface)
2 glass substrate (second substrate)
2
a prescribed surface (second surface)
2
b corner
3 sealing member
10 liquid crystal display panel (display panel)
11 switching element
12 pixel electrode
13 opposite electrode
13
a portion (portion of opposite electrode at corner of second substrate)
13
b cut-out
14 interlayer insulating film
14
a portion (portion of interlayer insulating film corresponding in position to corner of second substrate)
14
b cut-out
15 common wiring line
16 pad electrode
17 black matrix layer
17
a portion (portion of black matrix layer at corner of second substrate)
17
b cut-out
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-008871 | Jan 2011 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2012/050432 | 1/12/2012 | WO | 00 | 7/15/2013 |
