METHOD FOR PRODUCING DISPLAY PANEL

According to the present invention, a display panel having a narrow frame and having an irregular shape is produced by a fewer number of steps, and the end faces of the polarizing plates are made flush with the end face of the glass substrate. Rectangular polarizing plates (51, 52) are bonded to a separate glass substrate (2) including a display region (21) with a cutout (31). The contour (41) of the separate glass substrate (2) and the contours (61) of the polarizing plates (51, 52) are simultaneously cut with use of an end mill or a laser.

This Nonprovisional application claims priority under 35 U.S.C. § 119 on Patent Application No. 2017-242982 filed in Japan on Dec. 19, 2017, the entire contents of which is hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to a method for producing a display panel.

BACKGROUND ART

A method for producing a display panel includes many steps. Various techniques have been conventionally proposed for reducing the number of steps included in the method for producing a display panel.

Patent Document 1 discloses a method for producing a liquid crystal panel, characterized in that a display panel and two electrode substrate members, which include a plurality of electrode substrates preferably made of plastic, are bonded so as to face each other, polarizing plates are bonded to corresponding back surfaces of the electrode substrate members, and thereafter, an end portion of one of the electrode substrate members is cut together with the polarizing plates to provide a terminal area at a time.

Patent Document 2 discloses a method for producing a liquid crystal device, characterized by including the step of bonding an optical film to an outer surface of at least one of a first base substrate and a second base substrate before a large-sized panel is divided into separate panels.

Patent Document 3 discloses a method for producing a display device, including the steps of: bonding a first base substrate and a second base substrate to each other; bonding a first polarizing plate to the first base substrate; bonding a second polarizing plate to the second base substrate; and subjecting the first polarizing plate, the first base substrate, the second base substrate, and the second polarizing plate to dicing by batch.

CITATION LIST

Patent Literatures

SUMMARY OF INVENTION

Technical Problem

In recent years, a panel incorporated into a smart phone and a wearable device has had a narrower frame, and there has been a growing demand for a display panel having not only a narrower frame but also an irregular shape (circular shape, cutout, cut at corners, etc.). Applying the techniques disclosed in Patent Documents 1 to 3 to a method for producing a display panel including a glass substrate and having a narrow frame and an irregular shape gives rise to the following problems.

The technique disclosed in Patent Document 1 is applied to processing of an electrode substrate made of plastic, but is not applied to processing of a glass substrate.

The technique disclosed in Patent Document 2 is applicable to rectangular shape splitting of a glass substrate, but is not applicable to irregular shape processing of a glass substrate. The technique disclosed in Patent Document 3 requires performing the processing of the polarizing plates and the processing of a glass substrate at different times. Accordingly, it is necessary for a glass substrate maker and a polarizing plate maker to perform irregular shape processing of a glass substrate and irregular shape processing of the polarizing plates at different times. This increases the number of steps in the production method.

Furthermore, the techniques disclosed in Patent Documents 1 and 3 fail to make the end faces of the polarizing plates and the end faces of the glass substrate flush with each other.

The present invention has been attained to solve the above problems, and it is an object of the present invention to produce a display panel having a narrow frame and having an irregular shape by a fewer number of steps and to make the end faces of the polarizing plates flush with the end face of the glass substrate.

Solution to Problem

A method for producing a display panel in accordance with an aspect of the present invention includes the steps of: bonding a polarizing plate having a rectangular shape to a separate glass substrate, the separate glass substrate having a rectangular shape and including a display region having at least one cutout; and simultaneously cutting a contour of the separate glass substrate and a contour of the polarizing plate with use of an end mill or a laser.

Advantageous Effects of Invention

An aspect of the present invention yields the effect of processing a display panel having a narrow frame and having an irregular shape so that the end faces of the polarizing plates are made flush with the end face of the glass substrate and producing such a display panel having a narrow frame and having an irregular shape by a fewer number of steps.

DESCRIPTION OF EMBODIMENTS

FIG. 1is a view illustrating a large-sized glass substrate1including a plurality of display regions21with respective ones of cutouts31, in accordance with an embodiment of the present invention. (a) ofFIG. 1illustrates the large-sized glass substrate1when viewed from above, and (b) ofFIG. 1illustrates a cross section of the large-sized glass substrate1when viewed along a line A-A′ in (a) ofFIG. 1.

In carrying out a method for producing a display panel, a display panel maker first prepares a large-sized glass substrate1like the one illustrated inFIG. 1. The large-sized glass substrate1includes a color filter (CF) substrate11and a thin film transistor (TFT) substrate12. The CF substrate11and the TFT substrate12are glass substrates. As illustrated in (b) ofFIG. 1, the large-sized glass substrate1has a laminated structure of the CF substrate11and the TFT substrate12.

The large-sized glass substrate1includes a plurality of display regions21each having an irregular shape. The irregular shape means a non-rectangular shape. The display regions21each have cutouts31. Each of the display regions21has at least one cutout and may alternatively have other cutout which is different from the cutouts31. The display regions21are surrounded by respective ones of frame regions22. A connection region23is located on a lower side of the frame region22in a paper sheet ofFIG. 1. The connection region23is a region where a driver for driving the display region21is provided. The connection region23is also a region where a wiring to be connected to one end of a flexible printed circuit board (FPC) is formed. The FPC is a substrate for connecting the display panel to an external device. A place where the driver is mounted is not limited to the connection region23. The connection region23can alternatively be mounted on the FPC or on an external substrate.

On a surface of the CF substrate11which surface faces the TFT substrate12, various resin thin films are formed. Examples of the resin thin films include black matrix, a red color filter, a green color filter, and a blue color filter. These resin thin films are formed on the surface of the CF substrate in an area corresponding to the display region21.

On a surface of the TFT substrate12which surface faces the CF substrate11, TFTs and a wiring are formed. The TFTs are formed on the surface of the CF substrate11in an area corresponding to the display region21. The wiring is formed on the surface of the CF substrate11in areas corresponding to the display region21, the frame region22, and the connection region23.

Liquid crystal is injected into a space, provided between the CF substrate11and the TFT substrate12, corresponding to the display region21. Thus, the display region21is equivalent to a display region of a liquid crystal display section. The display region21, however, is not limited to such a display region, and can alternatively be a display region of an organic EL display section or a display region of other display section.

The rim of the frame region22coincides with contours41of the CF substrate11and the TFT substrate12in the display panel. As described in detail later, the contour41of the CF substrate11and the contour41of the TFT substrate12are simultaneously cut.

(Rectangular Shape Division of Large-Sized Glass Substrate1)

FIG. 2is a view illustrating a separate glass substrate2including one display region21with a cutout31, in accordance with an embodiment of the present invention. (a) ofFIG. 2illustrates the separate glass substrate2when viewed from above, and (b) ofFIG. 2illustrates a cross section of the separate glass substrate2when viewed along a line A-A′ in (a) ofFIG. 2. A display panel maker divides the large-sized glass substrate1illustrated inFIG. 1into a plurality of separate glass substrates2in cell units as illustrated inFIG. 2. The separate glass substrate2in cell unit means a separate glass substrate2including one display region21with a cutout31. In other words, the separate glass substrate2includes one display region21, one frame region22, and one connection region23.

The separate glass substrate2illustrated inFIG. 2is rectangular in shape. At this stage, a display panel maker cuts the separate glass substrate2at a part corresponding to the connection region23. Accordingly, in the connection region23of the separate glass substrate2, the TFT substrate12is present, but the CF substrate11is not present (as illustrated in (b) ofFIG. 2). Such exposure of the connection region23allows the driver to be provided in the connection region23and allows for connection to the FPC.

At this stage, the display panel maker does not perform irregular shape processing on the separate glass substrate2. In other words, in the separate glass substrate2, the contour41of the CF substrate11and the contour41of the TFT substrate12are not cut.

FIG. 3is a view illustrating polarizing plates51and52in accordance with an embodiment of the present invention. The polarizing plates51and52are prepared by a polarizing plate maker. Each of the polarizing plates51and52illustrated inFIG. 3has a cell unit size that accommodates the size of the separate glass substrate2into which the large-sized glass substrate1is divided in cell unit as illustrated inFIG. 2. The maker of the polarizing plates51and52first produces one or more large-sized polarizing plates and divides them into separate polarizing plates in cell units. Consequently, the polarizing plates51and52of a size illustrated inFIG. 3are produced. In an example case illustrated inFIG. 3, the polarizing plates51and52are larger in size than the display region21illustrated inFIG. 2. Before bonded to the large-sized glass substrate1, the polarizing plates51and52are rectangular in shape. In other words, the maker of the polarizing plates51and52does not perform irregular shape processing on the polarizing plates51and52in cell units.

The maker of the polarizing plates51and52delivers, to the display panel maker, the polarizing plates51and52in cell units illustrated inFIG. 3. Alternatively, the maker of the polarizing plates51and52can deliver one or more large-sized polarizing plates to the display panel maker, and the display panel maker can divide the one or more large-sized polarizing plates thus delivered into the polarizing plates51and52in cell units.

FIG. 4is a view illustrating the separate glass substrate2with the polarizing plates51and52bonded thereto, in accordance with an embodiment of the present invention. (a) ofFIG. 4illustrates a top surface of the separate glass substrate2with the polarizing plates51and52bonded thereto, and (b) ofFIG. 4illustrates a cross section of the separate glass substrate2when viewed along a line A-A′ in (a) ofFIG. 4. The display panel maker bonds the rectangular polarizing plate51illustrated inFIG. 3to the surface of the rectangular separate glass substrate2illustrated inFIG. 2on the CF substrate11side. The polarizing plate51is disposed on the surface of the CF substrate11in such a manner that the display region21is overlaid in whole with the polarizing plate51. The display panel maker further bonds the rectangular polarizing plate52illustrated inFIG. 3to the surface of the TFT substrate12in the rectangular separate glass substrate2illustrated inFIG. 2. The polarizing plate52is disposed on the surface of the TFT substrate12in such a manner that the display region21is overlaid in whole with the polarizing plate52.

Through the bonding of the polarizing plates51and52, the outlines61of the polarizing plates51and52are determined with respect to the separate glass substrate2. In the separate glass substrate2, the contour61coincides with the contours41. At this stage, the separate glass substrate2is not subjected to irregular shape processing.

FIG. 5is a view illustrating the display panel3obtained by irregular shape processing, in accordance with an embodiment of the present invention. (a) ofFIG. 5illustrates the display panel3when viewed from above, and (b) ofFIG. 5illustrates a cross section of the display panel3when viewed along a line A-A′ in (a) ofFIG. 5.

The display panel maker performs irregular shape processing simultaneously on the constituent components of the separate glass substrate2illustrated inFIG. 4, i.e., the CF substrate11, the TFT substrate12, the polarizing plate51, and the polarizing plate52. Specifically, contours41of the CF substrate11and the TFT substrate12and contours61of the polarizing plates51and52are simultaneously cut with use of an end mill or a laser. This produces a display panel3, as illustrated inFIG. 5, having a narrow frame and having an irregular shape.

Thereafter, to the irregularly-shaped display panel3, components such as a backlight module, a driver IC, and a flexible printed circuit board are mounted sequentially. This produces a display panel3in finished form. Note that a light guide plate contained in the backlight module has an irregular shape similarly to the irregular shape of the display region21and other components. However, the light guide plate, which is produced by injection molding with a plastic frame mold, is not subjected to irregular shape processing simultaneously with the CF substrate11, the TFT substrate12, the polarizing plate51, and the polarizing plate52.

As described above, according to a production method in accordance with an embodiment of the present invention, the polarizing plates51and52before subjected to irregular shape processing are bonded to the separate glass substrate before subjected to irregular shape processing, and thereafter, the separate glass substrate2and the polarizing plates51and52are simultaneously subjected to irregular shape processing with use of an end mill or a laser. Thus, it is possible to reduce the steps for the irregular shape processing process by one step, in comparison with the conventional technique of individually subjecting the separate glass substrate2and the polarizing plates51and52to irregular shape processing. This eliminates the maker of the polarizing plates51and52having to make a capital investment for irregular shape processing of the polarizing plates51and52. Furthermore, it is possible to reduce the time for producing the polarizing plates51and52. This consequently achieves reduction in cost of the polarizing plates51and52and securement of the capacity.

Moreover, by simultaneously subjecting the separate glass substrate2and the polarizing plates51and52to irregular shape processing with use of an end mill or a laser, it is possible to make the end faces of the polarizing plates51and52, the end face of the CF substrate11, and the end face of the TFT substrate12flush with one another in the produced display panel3.

FIG. 6is an explanatory view illustrating other example method for producing a display panel in accordance with an embodiment of the present invention. In carrying out the production method illustrated inFIG. 6, the display panel maker first prepares a large-sized glass substrate1, as illustrated inFIG. 1, including a plurality of display regions21having respective ones of cutouts31. Subsequently, as illustrated in (a) ofFIG. 6, the display panel maker divides the large-sized glass substrate1into medium-sized glass substrates4each including display regions which are fewer than the display regions of the large-sized glass substrate1and have respective ones of cutouts31. In (a) ofFIG. 6, the large-sized glass substrate1is divided into medium-sized glass substrates4each including three display regions21which have respective ones of the cutouts31. At this stage, the display panel maker does not subject the medium-sized glass substrate4to irregular shape processing.

The maker of the polarizing plates51and52first produces one or more large-sized polarizing plates. Thereafter, as illustrated in (b) ofFIG. 6, the maker of the polarizing plates51and52divides the one or more large-sized polarizing plates into rectangular polarizing plates51and52having a size that accommodates the size of the separate medium-sized glass substrates4illustrated in (a) ofFIG. 6. The maker of the polarizing plates51and52delivers, to the display panel maker, the polarizing plates51and52after the division, without subjecting them to irregular shape processing. Alternatively, the maker of the polarizing plates51and52can deliver one or more large-sized polarizing plates to the display panel maker, and the display panel maker can divide the one or more large-sized polarizing plates thus delivered into the polarizing plates51and52of a size illustrated in (b) ofFIG. 6.

The display panel maker bonds the rectangular polarizing plate51illustrated in (b) ofFIG. 6to the surface of the rectangular medium-sized glass substrate4illustrated in (a) ofFIG. 6on the CF substrate11side. The polarizing plate51is disposed on the surface of the CF substrate11in such a manner that three display regions21are overlaid in whole with the polarizing plate51. The display panel maker further bonds the rectangular polarizing plate52illustrated in (b) ofFIG. 6to the surface of the TFT substrate12in the rectangular separate glass substrate2illustrated in (a) ofFIG. 6. The polarizing plate52is disposed on the surface of the TFT substrate12in such a manner that the three display regions21are overlaid in whole with the polarizing plate52. This produces a medium-sized glass substrate4, as illustrated in (c) ofFIG. 6, including three display regions21with cutouts31and having the polarizing plates51and52bonded thereto.

The display panel maker does not subject the medium-sized glass substrate4illustrated in (c) ofFIG. 6to rectangular shape division into three separate glass substrates2in cell units. Instead, the display panel maker performs irregular shape processing simultaneously on the constituent components of the medium-sized glass substrate4illustrated in (c) ofFIG. 6, i.e., the CF substrate11, the TFT substrate12, the polarizing plate51, and the polarizing plate52. Specifically, contours41of the CF substrate11and the TFT substrate12and contours61of the polarizing plates51and52are simultaneously cut with use of an end mill or a laser. The display panel maker applies such simultaneous cutting to the contours41and the contours61at three different positions. This produces, from the medium-sized glass substrate4, three display panels3, as illustrated inFIG. 5, each having a narrow frame and having an irregular shape.

In the example case illustrated inFIG. 6, a display panel3having a narrow frame and having an irregular shape is obtained as in the example cases illustrated inFIGS. 1 to 5. Furthermore, the example case illustrated inFIG. 6achieves reduction in effort required to perform bonding of the polarizing plates51and52, in comparison with the case where the polarizing plates51and52are bonded to an individual separate glass substrate2in cell unit.

(Advantages of Display Panel3)

FIG. 7is an explanatory view illustrating the advantages of the display panel3produced by the production method in accordance with an embodiment of the present invention. (a) ofFIG. 7illustrates a cross section of the display panel3produced by the production method in accordance with an embodiment of the present invention. (b) ofFIG. 7illustrates a cross section of a display panel3produced by the conventional production method. In an example case illustrated inFIG. 7, the display panel3is a liquid crystal display panel. The display panel3includes a reflecting sheet71, a light guide plate72, a diffusing sheet73, an upper lens sheet74, a lower lens sheet75, a plastic frame76, a double-sided tape77, a polarizing plate52, a TFT substrate12, a CF substrate11, and a polarizing plate52. The reflecting sheet71, the light guide plate72, the diffusing sheet73, the upper lens sheet74, the lower lens sheet75, and the plastic frame76constitutes a backlight module. The polarizing plate52and the plastic frame76are adhered to each other with the double-sided tape77.

The cross section illustrated in (a) ofFIG. 7contains the cross section when viewed along the line A-A′ inFIG. 5. In (a) ofFIG. 7, all of the respective end portions of the polarizing plate52, the TFT substrate12, the CF substrate11, and the polarizing plate51are located identically at the position81. This allows an area where the polarizing plate52, the double-sided tape77, and the plastic frame76are close to one another in the display panel3to be kept away from a boundary83of the display region21. This allows the inner wall of the plastic frame76to be kept away from the boundary83of an active region. Thus, light73having traveled through the light guide plate72and having been reflected by the inner wall of the plastic frame76is blocked by a hood-like portion of the double-sided tape77. Consequently, it is possible to prevent the light73from leaking to the display region21.

The display panel3illustrated in (b) ofFIG. 7is produced by a production method according to the conventional technique. The following will gives a brief explanation of the procedure of the production method. The maker of the display panel3performs irregular shape processing on the separate glass substrate2including the TFT substrate12and the CF substrate11. The maker of the polarizing plates51and52performs irregular shape processing on each of the polarizing plates51and52individually. The maker of the display panel3bonds the polarizing plate51having undergone irregular shape processing to the CF substrate11and bonds the polarizing plate52having undergone irregular shape processing to the TFT substrate12.

In (b) ofFIG. 7, the respective ends of the TFT substrate12and the CF substrate11and the respective ends of the polarizing plates51and52are not located identically at the position81and are displaced individually from the position81. Thus, the inner wall of the plastic frame76cannot be kept away from the boundary83of the active region. This does not allow light73having traveled through the light guide plate72and having been reflected by the inner wall of the plastic frame76to be blocked by the hood-like portion of the double-sided tape77. This may leak the light73from outside the double-sided tape77toward the display region21.

The display panel produced in accordance with an embodiment of the present invention is not limited to a liquid crystal display panel and can be other kinds of display panels.

First aspect: A method for producing a display panel, including the steps of: bonding a polarizing plate having a rectangular shape to a separate glass substrate, the separate glass substrate having a rectangular shape and including a display region having at least one cutout; and simultaneously cutting a contour of the separate glass substrate and a contour of the polarizing plate with use of an end mill or a laser.

Second aspect: The method according to the first aspect, wherein the display region comprises a plurality of display regions, the method further including the step of: dividing a glass substrate including the plurality of display regions each having the at least one cutout into separate glass substrates, the separate glass substrates each having a rectangular shape and each including a respective one of the plurality of display regions, in the bonding step, bonding the polarizing plate to each of the separate glass substrates into which the glass substrate has been divided.

The present invention is not limited to the embodiments, but can be altered by a skilled person in the art within the scope of the claims. The present invention also encompasses, in its technical scope, any embodiment derived by combining technical means disclosed in differing embodiments. Further, it is possible to form a new technical feature by combining the technical means disclosed in the respective embodiments.

REFERENCE SIGNS LIST