JP2008165219A - Flexible driver ic - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flexible driver IC which has flexibility and ductility. <P>SOLUTION: The flexible driver IC is for driving and is formed on a silicon wafer, where the silicon wafer is polished and the driver IC is made to have a thickness of not larger than 100 μm, and is connected to a display panel directly or after being mounted on a flexible FPC. The flexible driver IC is used while connected to a flexible display panel which displays information on an image etc., by moving a display medium by charging at least one kind of display medium in the space between two flexible counter substrates, at least one of which is transparent, and applying an electric field to the display medium, the display medium being composed of a particle group comprising at least one or more kinds of particles and having optical reflectivity and charging property. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

    The present invention relates to a flexible driver IC, and more particularly to a flexible driver IC used for driving a flexible display.

    As an information display device that replaces a liquid crystal display device (LCD), an information display device using techniques such as an electrophoretic method, an electrochromic method, a thermal method, and a two-color particle rotation method has been proposed.

    Compared to LCDs, these conventional technologies have advantages such as a wide viewing angle close to that of ordinary printed materials, low power consumption, and a memory function. It is considered as a technology that can be used for mobile phones, and is expected to expand to information display for mobile terminals, electronic paper, and the like. Recently, an electrophoretic method has been proposed in which a dispersion liquid composed of dispersed particles and a solution is microencapsulated and placed between opposing substrates.

    In particular, at least one type of display medium having at least one type of particles and having optical reflectivity and chargeability is enclosed in a space formed between two opposing substrates, at least one of which is transparent. An information display panel that displays information such as an image by moving the display medium by applying an electric field to the display medium is known. However, although it is called electronic paper, it is practically limited to displays using a glass substrate. Like paper, there are only electronic papers that have display memory properties but are not flexible. Application of the display panel as a flexible display is also being studied by configuring the panel constituent members including the substrate from flexible members.

Also, a TFT element and a driver IC are simultaneously manufactured on a glass substrate, transferred onto a resin substrate using a transfer technique, and an active matrix type display substrate including the TFT element and the driver IC is formed. A substrate and a substrate manufacturing method are known in which the TFT element and driver IC on the substrate are not peeled off from the substrate and the TFT element and driver IC are not broken even when bent (for example, Patent Document 1).
In order to improve such a situation, the inventors of the present invention have proposed a panel in which a glass substrate is replaced with a resin so as to have flexibility. However, if the driver IC for driving the display is rigid even if only the panel is flexible, it is difficult to say that it is truly flexible. In addition, the application to electronic paper has been mainly described. However, if the display is flexible, the flexible driver IC of the present invention can be used without any problem, and a flexible LCD and a flexible PDP can be obtained.
JP 2004-235238 A

    The example of Patent Document 1 described above is an integrated technology of a TFT element and a driver IC, and there has never been an example in which a flexible driver IC is manufactured. Also, even if a driver IC formed on a glass plate using this transfer method is formed on a resin film, the driver IC is not easily peeled off from the resin film, and the rigid driver IC portion is flexible. However, since the mounting process is complicated, it becomes expensive and has little economic value. There is also a problem in that this technique is not realized until the technology is formed integrally with an expensive TFT element. Accordingly, an object of the present invention is to solve the above-mentioned problems and provide a flexible driver IC having flexibility and flexibility used for driving a flexible display so that a truly flexible flexible display can be obtained. There is to do.

  The flexible driver IC of the present invention is a driver IC for driving formed on a silicon wafer. The silicon wafer is polished and the thickness of the driver is 100 μm or less, preferably 50 μm or less, more preferably 40 μm or less. When connecting to the display panel, it is connected to the display panel directly or after being mounted on a flexible FPC. The display panel here includes a portion where the pixel electrodes and the peripheral electrodes of the upper and lower substrates constituting the display panel are gathered, and the connection is usually made at a portion where the peripheral electrodes are gathered. The electrode material is generally a flexible display panel formed of a metal or a ceramic electrode material such as ITO or IZO generally used as a transparent pixel electrode.

  Further, the flexible driver IC of the present invention can be mounted on an information display panel constituted by a liquid crystal display, a PDP, or the like, or an electronic paper configured as a flexible display to be a truly flexible display. However, at least one display medium having at least one kind of particles and having optical reflectance and chargeability is sealed in a space between two opposing substrates, at least one of which is transparent, By applying an electric field, a truly flexible flexible display can be obtained particularly well when used by being connected to a flexible display that displays information such as images by moving the display medium.

  According to the present invention, it is a driver IC for driving formed on a silicon wafer, the silicon wafer is polished, the driver IC is made to have a thickness of 100 μm or less, and when connected to the display panel, By mounting on a flexible FPC and then connecting to a display panel, it is possible to provide a flexible driver IC that is flexible and flexible, particularly for use in circuit boards for flexible displays. It can be a display. In order to increase the flexibility of the driver IC of the present invention, the thickness is preferably 50 μm or less, and more preferably 40 μm or less.

  First, a basic configuration of a display panel or electronic paper that is an object of the present invention will be described. The display panel and electronic paper targeted by the present invention can be used without any problem as long as they are so-called displays. However, among liquid crystal displays, PDPs, electronic papers, etc. A flexible display can be obtained. Among these, the most suitable flexible display panel is configured such that an electric field is applied to a display medium having optical reflectivity and chargeability enclosed in a space between two opposing flexible substrates, and the applied electric field direction is aligned. This is a flexible display panel of a type in which information such as an image is displayed when the display medium is attracted by a force due to an electric field, a Coulomb force, or the like, and the display medium moves due to a change in the direction of the electric field. In this type of flexible display panel, therefore, it is necessary to design the panel so that the display medium moves uniformly and can maintain stability when rewriting the display repeatedly or when displaying the display information continuously. There is. The display panel thus obtained can be configured to be capable of simple matrix driving and is the most suitable configuration for flexibility, and the flexibility can be achieved in total with the flexible driver.

  An example of a display panel that is an object of the present invention will be described with reference to FIGS. 1 (a) and 1 (b) to FIG.

  In the example shown in FIGS. 1A and 1B, at least two or more types of display medium 3 (here, configured as a group of particles having different optical reflectivity and charging characteristics composed of at least one type of particles). The electrode provided on the substrate 1 in each cell formed by the partition walls 4, showing a white display medium 3 </ b> W composed of a particle group of display white particles 3 </ b> Wa and a black display medium 3 </ b> B composed of a particle group of display black particles 3 </ b> Ba). 5 is moved vertically to the substrates 1 and 2 according to an electric field generated by applying a voltage between the electrode 5 (individual electrode) and the electrode 6 (individual electrode) provided on the substrate 2. Then, as shown in FIG. 1A, the white display medium 3W is visually recognized by the observer and white dot display is performed, or as shown in FIG. 1B, the black display medium 3B is visually recognized by the observer. Black dots are displayed. In addition, in FIG. 1 (a), (b), the partition in front is abbreviate | omitted. The electrode may be provided outside the substrate, or may be provided so as to be embedded inside the substrate.

  In the example shown in FIGS. 2 (a) and 2 (b), at least two or more types of display media 3 (here, configured as a group of particles having different optical reflectance and charging characteristics composed of at least one type of particles). The electrode provided on the substrate 1 in each cell formed by the partition walls 4, showing a white display medium 3 </ b> W composed of a particle group of display white particles 3 </ b> Wa and a black display medium 3 </ b> B composed of a particle group of display black particles 3 </ b> Ba). 5 (line electrode) and the electrode 6 (line electrode) provided on the substrate 2 are moved perpendicularly to the substrates 1 and 2 in accordance with an electric field generated by applying a voltage. Then, as shown in FIG. 2A, the white display medium 3W is visually recognized by the observer and white dot display is performed, or as shown in FIG. 2B, the black display medium 3B is visually recognized by the observer. Black dots are displayed. In addition, in FIG. 2 (a), (b), the partition in front is abbreviate | omitted. The electrode may be provided outside the substrate, or may be provided so as to be embedded inside the substrate.

  In the example shown in FIGS. 3A and 3B, the display medium 3 (here, display white particles) configured as a particle group having at least an optical reflectance and a chargeability composed of at least one kind of particles. In accordance with the electric field generated by applying a voltage between the electrode 5 and the electrode 6 provided on the substrate 1 in each cell formed of the partition wall 4, indicating a white display medium 3 </ b> W composed of 3 Wa particles. Then, it is moved in the direction parallel to the substrates 1 and 2. Then, as shown in FIG. 3 (a), the white display medium 3W is visually recognized by the observer to display white dots, or as shown in FIG. 3 (b), the color of the black plate 7 is changed to the observer. The black dots are displayed by visually recognizing. In addition, in the example shown to Fig.3 (a), (b), the partition in front is abbreviate | omitted. The electrode may be provided outside the substrate, or may be provided so as to be embedded inside the substrate. The same display can be performed even when the white display medium is replaced with a black display medium and the black plate is replaced with a white plate.

  In the example shown in FIGS. 4A and 4B, an example of color display in which a display unit is configured by three cells is shown. In the example shown in FIGS. 4A and 4B, all the cells 21-1 to 21-3 as the display medium are filled with the white display medium 3W and the black display medium 3B, and the first cell 21-1. A red color filter 22R is provided on the viewer side, a green color filter 22G is provided on the viewer side of the second cell 21-2, a blue color filter 22BL is provided on the viewer side of the third cell 21-3, A display unit is composed of three cells, the first cell 21-1, the second cell 21-2, and the third cell 21-3. In this example, as shown in FIG. 4A, the white display medium 3 </ b> W is moved in the first cell 21-1 to the third cell 21-3 on the viewer side, so that The white dot display is performed, and as shown in FIG. 4B, the black display medium 3B is moved in the first cell 21-1 to the third cell 21-3 to the observer side. In contrast, black dots are displayed. Multicolor display can be performed by moving the display medium of each cell. In addition, in FIG. 4 (a), (b), the partition in front is abbreviate | omitted. The electrode may be provided outside the substrate, or may be provided so as to be embedded inside the substrate.

  In the example shown in FIGS. 5 and 6, another example in which black and white dot display is performed using the line electrodes 5 and 6 is described in the same manner as the example shown in FIGS. In the example shown in FIG. 5, the white display medium 3W and the black display medium are used instead of the cells formed by the partition walls 4 filled with the white display medium 3W and the black display medium 3B shown in FIGS. A microcapsule 9 filled with 3B together with the insulating liquid 8 is used. Moreover, in the example shown in FIG. 6, instead of the cell formed of the partition wall 4 filled with the white display medium 3W and the black display medium 3B shown in FIGS. A microcapsule 9 filled with an insulating liquid 8 is used as a display medium with rotating balls 10 that are separately coated and have opposite polarities. In both examples shown in FIGS. 5 and 6, monochrome dot display can be performed in the same manner as the example shown in FIG. The electrode may be provided outside the substrate, or may be provided so as to be embedded inside the substrate.

By polishing the silicon wafer portion of the driver IC for driving formed on the silicon wafer so that the driver IC is 100 μm or less, the driver IC that is normally used has flexibility and flexibility. Here, as a technique for polishing the silicon wafer, for example, CMP (Chemical Mechanical Polish) polishing is used. However, simply polishing and thinning will cause defects such as fine cracks and the silicon wafer will be easily broken, so it is better to perform a commonly used stress-free process. Further, in order to eliminate the ease of breakage, when connecting to the display panel, reinforcement is performed using a flexible member such as a protruding portion such as an adhesive tape or an anisotropic conductive adhesive. In this way, it is possible to provide a flexible driver IC with high practicality by performing reinforcement so that stress is not partially biased, such as embedding with an adhesive tape or an adhesive.
The thinner the driver IC, the greater the flexibility (flexibility) and flexibility. However, when the driver IC is too thin, the driver IC will not function as a driver IC, when an impact is applied, or when processing thinly Therefore, it is preferable to secure a certain thickness. On the other hand, when the thickness exceeds 100 μm, there is a disadvantage that a truly flexible display cannot be obtained.
In CMP polishing, it is confirmed that processing up to 5 μm thickness is possible and the driver IC function can also be demonstrated. However, it is often damaged by processing after processing, and from the viewpoint of productivity, processing after processing is difficult. A thickness of 30 μm or more that is easy and does not increase production costs can be said to be a practically preferable range.

7A and 7B are configuration diagrams of a flexible display using the flexible driver IC of the present invention. FIG. 7A shows a flexible driver IC mounted on a circuit formed in the peripheral part of the upper and lower substrates constituting the flexible display panel. FIG. 7 (b) shows a state in which the circuit is mounted on a flexible printed circuit (FPC) generally called COF (chip on film) or TCP (tape carrier package) and then connected to a flexible display panel.
For mounting the flexible driver IC, an anisotropic conductive film method, an ultrasonic bonding method, a solder reflow method, or the like is generally used. Reinforcement with the above-mentioned adhesive is when ACF is used, and in the case of ultrasonic bonding method and solder reflow method, it is reinforced with an underfill material and then laminated with an adhesive tape etc. to further increase flexibility and strength. And can be improved.

Hereinafter, a display panel which is an object of the present invention will be described.
Since it is a driver for driving a display panel that is basically polished to 100 μm or less, it can be used for any display as a driver. That is, active drive liquid crystal display, passive drive liquid crystal display, plasma display, inorganic EL display, organic EL display, cholesteric liquid crystal display classified into electronic paper technology, electrophoretic display, MEMS display, bistable TN liquid crystal display, electrochromic display More specifically, the electrophoretic display further includes many displays such as a microcapsule type, a microcup type, and a twist ball type, and can be applied to all of them. The effects included in the technology of the present invention are not only flexible, but also lead to a reduction in total thickness. Recently, mobile phones and digital cameras are becoming more and more multifunctional, and there are many demands for adding functions without changing the thickness. In this respect, the driving driver having a reduced thickness is useful.
Further, among these exemplified display panels, any flexible display panel can be used more suitably. Even if it is used for any part of the display panel, flexibility can be expressed as a total, and the initial purpose can be achieved.
However, it is not easy to make any display panel flexible. Sometimes it is just technically possible. In that respect, the display panel using the electronic paper technology has one purpose of making it flexible, and for the first time using the flexible driver IC of the present invention for this electronic paper display, the value in a comprehensive sense is born as a substitute for paper. come.

  Further, the most effective display panel that is an object of the present invention will be described.

  As for the substrate, at least the substrate on the viewing side is a transparent flexible substrate capable of confirming the color of the display medium from the outside of the display panel, and a material having high visible light transmittance and good heat resistance is suitable. The substrate on the back side may be transparent or opaque, but is a flexible substrate using a flexible material. Examples of the substrate material include polymer sheets such as polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyethylene, polycarbonate, polyimide, and acrylic, and flexible materials such as metal sheets. The thickness of the substrate is preferably from 2 to 2000 μm, more preferably from 5 to 1000 μm. If it is too thin, it will be difficult to maintain the strength and the uniform spacing between the substrates, and if it is thicker than 2000 μm, there will be inconvenience in flexibility.

  As electrode materials provided for the display panel, metals such as aluminum, silver, nickel, copper, and gold, indium tin oxide (ITO), indium oxide, zinc-doped indium oxide (IZO), aluminum-doped zinc oxide (AZO), conductive Conductive metal oxides such as conductive tin oxide, antimony tin oxide (ATO), and conductive zinc oxide, and conductive polymers such as polyaniline, polypyrrole, and polythiophene are exemplified and used as appropriate. As a method of forming an electrode, a method of forming the above-described materials into a thin film by sputtering, vacuum deposition, CVD (chemical vapor deposition), coating, or the like, or a method of laminating metal foil (for example, rolled copper foil) Alternatively, a method in which a conductive agent is mixed and applied to a solvent or a synthetic resin binder is used. The electrode provided on the display surface side substrate 2 which is on the viewing side and needs to be transparent needs to be transparent, but the electrode provided on the back side substrate 1 does not need to be transparent. In any case, the above-mentioned material that can be patterned and is electrically conductive can be suitably used. Note that the electrode thickness may be 0.01 to 10 [mu] m, preferably 0.05 to 5 [mu] m, as long as conductivity can be ensured and light transmittance is not hindered. The material and thickness of the electrode provided on the back side substrate 1 are the same as those of the electrode provided on the display surface side substrate described above, but need not be transparent. In this case, the external voltage input may be superimposed with direct current or alternating current.

In the partition provided when cells are formed in the space between the substrates of the display panel, the height and width of the partition are appropriately set according to the type of display medium involved in the display, and are not limited in general. The height of the partition wall is adjusted to 100 μm, preferably 3 to 50 μm, and the height of the partition wall is 10 to 500 μm, preferably 10 to 200 μm. In particular, in a display panel using a group of particles containing chargeable particles as a display medium, the height of the partition wall is adjusted to 10 to 100 μm, preferably 10 to 50 μm. By reducing the gap between the substrates in this way, not only a flexible display panel can be obtained in combination with the structure of the flexible substrate, but also a high electric field can be obtained even when a low voltage is applied. This is preferable because the driveability of the particle group containing particles) is improved. As shown in FIG. 8, the cells in the display panel obtained by superimposing the display side substrate and the back side substrate are illustrated in a square shape, a triangular shape, a line shape, a circular shape, and a hexagonal shape as viewed from the substrate plane direction. Is exemplified by a lattice shape, a honeycomb shape, or a mesh shape. Various shapes are used depending on the shape of the partition wall. It is better to make the portion corresponding to the partition cross section visible from the display surface side (the area of the cell frame formed by the partition width) as small as possible, and the display state becomes clearer.
Examples of the method for forming the partition include a mold transfer method, a screen printing method, a sand blast method, a photolithography method, and an additive method. Any of these methods can be suitably used for the display panel of the present invention. Of these, a flexible partition wall can be obtained using a photolithographic method in which a flexible partition film is obtained using a flexible resist film or a flexible transfer material. A mold transfer method is preferably used.

Next, display particles (hereinafter also referred to as particles) constituting a particle group used as a display medium in the display panel that is the subject of the present invention will be described. The display particles are used as they are as a display medium by forming a particle group with the display particles alone, or as a display medium by forming a particle group together with other particles.
The particles can contain a charge control agent, a colorant, an inorganic additive, and the like, if necessary, in the resin as the main component, as in the conventional case.

In a display panel in which a display medium configured as a group of particles including a chargeable particle is driven in a gas space, it is important to manage the gas in the gap surrounding the display medium, which contributes to improved display stability. Specifically, it is important that the relative humidity at 25 ° C. is 60% RH or less, and preferably 50% RH or less for the humidity of the gas in the gap.
1A and 1B, electrodes 5 and 6 (when electrodes are provided inside the substrate) from the portion sandwiched between the opposing substrate 1 and substrate 2 in FIG. 3, the occupied portion of the partition 4 (when the partition is provided), and the gas portion in contact with the so-called display medium, excluding the seal portion of the display panel.
The gas in the gap is not limited as long as it is in the humidity region described above, but dry air, dry nitrogen, dry argon, dry helium, dry carbon dioxide, dry methane, and the like are preferable. This gas needs to be sealed in the display panel so that the humidity is maintained. For example, the display medium is filled and the display panel is assembled in a predetermined humidity environment. It is important to apply a sealing material and a sealing method to prevent intrusion.

  When the display medium configured as a particle group including the chargeable particles to be an object of the present invention is a display panel that is driven in the gas space, the volume occupation ratio of the display medium in the gas space between the opposing substrates is 5. -70% is preferable, More preferably, it is 5-60%. When it exceeds 70%, the movement as a display medium is hindered, and when it is less than 5%, the contrast tends to be unclear.

(1) First Example After forming a ternary output driver IC (withstand voltage of 90V) with a bump of 30 μm in a wafer state, a reinforcing film is applied to the circuit side and polished to a thickness of 50 μm. Then, a driver IC was manufactured through a normal process such as a stress-free process. Thereafter, a dicing tape was applied to the silicon side, and the reinforcing film was peeled off before dicing.
FIGS. 9A and 9B show the configuration of the driver IC used in the embodiment A of the first embodiment of the present invention. As shown in FIG. 9A, the film-like anisotropic conductive adhesive 34 was mounted on a TCP substrate (FPC) 36. At this time, the anisotropic conductive adhesive 34 having a height of 50 μm was used in consideration of the height of the bump 33 of the adhesive portion and the height of the TCP electrode 35 of 20 μm. Since the anisotropic conductive adhesive 34 that protrudes at the time of crimping contaminates the crimping head, a polyester film 31 having a thickness of 100 μm is placed on the flexible driver IC 32 and heat-pressed using a crimping machine, and the configuration shown in FIG. did. The polyester film 31 was bonded with a protruding anisotropic conductive adhesive so as to wrap the driver IC and used as a reinforcing sheet.
In this example, a film-like anisotropic conductive adhesive (ACF) was used, but the anisotropic conductive adhesive can be suitably used as long as it is not a film and has a high viscosity. An anisotropic conductive sealant (ACS) that enhances sealing properties and has both adhesive properties and sealing properties can also be used.
Further, the display panel having the configuration shown in FIG. 2 (a black display medium and a white display medium are sealed between panel substrates combined with a flexible substrate with an ITO line electrode) using a film-like anisotropic conductive adhesive 34. And mounted on a circuit board of a flexible display panel. A circuit board on which a driver was mounted was placed on the back side of the display panel to obtain a display panel, which was used as a display panel manufacturing example of Example A. Moreover, as a display panel manufacturing example of Example B, a display panel was obtained in the same manner as the display panel manufacturing example of Example A except that a driver IC manufactured without using the polyester film 31 was mounted.
Moreover, after performing the bending operation | movement in the bending test shown below once, and after performing predetermined 10 times, the test pattern display was performed.

(2) Second Example A display panel is manufactured by the same display panel manufacturing examples of Examples C and D as the first example except that the driver IC is polished to a thickness of 35 μm, and the driver IC is further 30 μm thick. A display panel was fabricated and evaluated in the same manner as in the display panel fabrication example of Examples C ′ and D ′, except that the first panel was polished. In the display panel manufacturing examples of Examples C and C ′, similarly to the display panel manufacturing example of Example A, the driver IC manufactured using the polyester film 31 is mounted, and the display panel manufacturing examples of Examples D and D ′ are mounted. In the same manner as in the display panel manufacturing example of Example B, a driver IC manufactured without using the polyester film 31 was mounted.
Moreover, after performing the bending operation | movement in the bending test shown below once, and after performing predetermined 10 times, the test pattern display was performed.

(3) Third Example A display panel was produced and evaluated in the same manner as in Examples E and F except that the driver IC was polished to a thickness of 100 μm as in the first and second examples. It was. The display panel manufacturing example of Example E is mounted with a driver IC manufactured using the polyester film 31 in the same manner as the display panel manufacturing examples of Examples A and C, and the display panel manufacturing example of Example F is an example. Similarly to the B and D display panel manufacturing examples, a driver IC manufactured without using the polyester film 31 was mounted.
Also in this case, the anisotropic conductive adhesive (ACF) that protruded to the periphery went around to the upper part of the driver IC, and sufficient reinforcement could be achieved.
A test pattern was displayed on the display panel after the bending operation in the bending test described below was performed once and after a predetermined ten times.

(4) Fourth Embodiment FIGS. 10A and 10B show the configuration of a driver IC used in display panel manufacturing examples of Examples GI ′ of the fourth embodiment of the present invention. A Teflon (registered trademark) sheet is placed in place of the polyester film 31 used in the first to third embodiments (in other words, a Teflon (registered trademark) sheet is used in the fourth embodiment), and the Teflon after pressure bonding is used. The (registered trademark) sheet was peeled off, and an adhesive tape was applied to the flexible driver IC 32 for reinforcement. As a pressure-sensitive adhesive tape, a commercially available product (trade name: Cellotape (registered trademark)) is used. However, the present invention is not limited to this, and any pressure-sensitive adhesive tape may be used.
Further, the display panel having the configuration shown in FIG. 2 (a black display medium and a white display medium are sealed between panel substrates combined with a flexible substrate with an ITO line electrode) using a film-like anisotropic conductive adhesive 34. And mounted on a circuit board of a flexible display panel. A circuit board on which the driver IC was mounted was placed on the back side of the display unit panel to obtain a display panel.
Example G for producing a display panel using a driver IC having a thickness of 100 μm Example G, Example H for producing a display panel using a driver IC having a thickness of 50 μm, Example of producing a display panel using a driver IC having a thickness of 35 μm Example I, An example of manufacturing a display panel using a driver IC having a thickness of 30 μm is referred to as Example I ′.
Moreover, after performing the bending operation | movement in the bending test shown below once, and after performing predetermined 10 times, the test pattern display was performed.

(5) Comparative Example Using a general driver IC having a thickness of 700 μm, the driver IC is mounted on each flexible display panel according to the display panel manufacturing examples of Comparative Examples A and B in the same manner as the above-described embodiment. A display panel was manufactured and evaluated in the same manner.
The display panel of the comparative panel A fabrication example was fabricated by the same method as the display panel fabrication method of Example A, except that a 700 μm thick driver IC was used.
The display panel of the display panel fabrication example of Comparative Example B was fabricated by the same method as the display panel fabrication method of Examples GI ′ except that a 700 μm thick driver IC was used.
Moreover, after performing the bending operation | movement in the bending test shown below once, and after performing predetermined 10 times, the test pattern display was performed.

  Table 1 shows configurations of the first to fourth examples and the comparative example described above.

The flexible display panel used in the examples and comparative examples will be described.
A base material made of polyester (manufactured by Teijin DuPont), PEN (polyethylene naphthalate: made by Teijin DuPont), PES (polyethersulfone), polyimide (manufactured by Ube Industries) is prepared. A grid-like partition wall having an inch and an aspect ratio of 3: 4, a rib width of 10 μm, and a pitch of 150 μm was formed, and two types of black and white display media were bonded to each other with an epoxy adhesive and sealed. The flexible display mounted on each of the four types of flexible display panels thus configured was evaluated using the driver IC mounting method shown in Table 1.
The partition walls were formed by laminating a dry film photoresist NIT250 manufactured by Nichigo Morton, which is a photosensitive film, and exposing and developing. The resist film was used to form a resist layer having a predetermined thickness and a partition wall having a predetermined height.

A driver IC was mounted on the flexible display panel according to the display panel manufacturing example.
The display panel according to the display panel manufacturing example of Examples A to I ′ is rich in flexibility including the connected driver IC, and the display in which the driver IC is mounted on the flexible display panel according to the display panel manufacturing examples of Comparative Examples A and B Compared with the panel, the flexibility (flexibility) has been greatly improved, and it has become a truly flexible display panel.
In each of the display panel preparation examples of Comparative Examples A and B, the anisotropic conductive adhesive (ACF) protrudes to the periphery, but does not go to the upper part of the IC chip, and the polyester film arranged for reinforcement is adhered. It did not fulfill its reinforcing function.

In the image quality displayed after one bending operation, the display panels according to Examples A to I ′ were all in a good display state.
In the image quality displayed after 10 bending operations (after completion of the bending test used for the evaluation), the display according to Examples A, C, and E rather than the display panel according to Examples B, D, and F. The panel was a better display state. This is presumably because the driver IC was destroyed during the bending test in the bending test in which the bending operation was repeated 10 times in the display panels according to the examples B, D, and F. In the display panels according to the examples G to I ′, a result that can be said to be a good display state was obtained in the quality of the display image after the bending test in which the bending operation was repeated 10 times.
In the display panel according to the display panel manufacturing example of Comparative Example A, the first bend (the stroke distance of the telescopic bending tester 37 is gradually narrowed (FIG. 11B)), and the display panel length of the set display panel 38 is displayed. The IC chip was peeled off from the substrate.
In the display panel according to the display panel manufacturing example using the adhesive tape of Comparative Example B, the IC chip was attached to the substrate even after the test was repeated by repeating the bending 10 times, but the IC chip was cracked.

The bending test will be described.
As shown in FIGS. 11 (a), (b), and (c), the display panel constituted by the flexible display panel and the driver IC is set in a telescopic bending tester 37 that can change the distance, A bending test was performed. In the bending test, after setting the state of FIG. 11A, the stroke distance of the telescopic bending tester 37 is gradually narrowed (FIG. 11B), and the display panel length of the set display panel 38 is divided into two. (Fig. 11 (c)), this time, the stroke range of the telescopic bending tester 37 was gradually widened and returned to the original position by repeating the operation 10 times. After the first bending operation, the state of the display panel is visually observed and then a predetermined test pattern is displayed. Further, the bending operation is repeated nine times, and the bending operation is performed a total of ten times to complete the test.

A flexible display panel according to the present invention includes a notebook computer, an electronic notebook, a portable information device called PDA (Personal Digital Assistants), a display unit of a mobile device such as a mobile phone, a handy terminal, an electronic book, an electronic newspaper, an electronic manual ( Electronic paper such as instruction manuals, signboards, posters, bulletin boards such as blackboards (whiteboards), electronic desk calculators, display units for home appliances, automobile supplies, card display units such as point cards and IC cards, electronic advertisements, In addition to information boards, electronic POPs (Point Of Presence, Point Of Purchase advertising), electronic price tags, electronic shelf labels, electronic musical scores, and display units for RF-ID devices, main display units such as POS terminals, car navigation devices, and watches Alternatively, the auxiliary display unit is used integrally with the flexible display panel. Of course, it may be flat as in the case of the glass substrate, but in many cases, it is bent in an arbitrary shape or can be freely bent by the user. In addition, by making it flexible, there is an advantage that it does not break even if dropped while carrying.
Conventionally, since only the display panel has been flexible, the driver for driving is concentrated on one side, and the driving circuit and the battery are combined in one place, thereby avoiding the design and making it a flexible display.
However, with the flexible driver IC of the present invention, the entire display panel is flexible no matter which periphery of the display panel is connected to the driver for driving or where the driver for driving is connected to any position on the display panel. Even if it is integrated with a circuit board (FPC) designed to be flexible, it is possible to provide a display module that is light, flexible, and not easily broken without impairing the flexibility of the circuit board, and can be applied to displays that require more mobility. .

    As for the display panel driving method to which the flexible driver IC of the present invention is applied, a simple matrix driving method and a static driving method that do not use a switching element in the panel itself, and a three-terminal switching element represented by a thin film transistor (TFT) Alternatively, various types of driving methods such as an active matrix driving method using a two-terminal switching element represented by a thin film diode (TFD), a segment driving method, and a dynamic driving method can be used.

(A), (b) is a figure which shows an example of the display panel used as the object of this invention, respectively. (A), (b) is a figure which shows the other example of the display panel used as the object of this invention, respectively. (A), (b) is a figure which shows the further another example of the display panel used as the object of this invention, respectively. (A), (b) is a figure which shows the further another example of the display panel used as the object of this invention, respectively. It is a figure which shows the further another example of the display panel used as the object of this invention. It is a figure which shows the further another example of the display panel used as the object of this invention. (A), (b) shows the block diagram of the flexible display using the flexible driver IC of this invention, respectively. It is a figure which shows an example of the shape of the partition in the display panel used as the object of this invention. (A), (b) shows the configuration of the driver IC used in Example A of the first embodiment of the present invention. (A), (b) shows the configuration of the driver IC used in Example A of the fourth embodiment of the present invention. (A), (b), (c) is a figure which shows the expansion-contraction type | mold bending test machine respectively used by evaluation of this invention.

Explanation of symbols

1, 2 Substrate 3 Display medium 3W White display medium 3Wa White particles for display (chargeable white particles)
3B Black display medium 3Ba Black particles for display (chargeable black particles)
4 Partition 5 and 6 Electrode 7 Black plate 8 Insulating liquid 9 Microcapsule 10 Rotating ball 21-1 1st cell 21-2 2nd cell 21-3 3rd cell 22R Red color filter 22G Green color filter 22BL Blue color Filter 31 Polyester film 32 Driver IC (flexible driver IC)
33 Bump 34 Anisotropic conductive adhesive 35 Electrode 36 FPC (flexible printed circuit)
37 Telescopic bending tester 38 Display panel

Claims (5)

In a driver for driving formed on a silicon wafer,
A flexible driver IC, wherein the silicon wafer is polished so that the driver has a thickness of 100 μm or less.   The flexible driver IC according to claim 1, wherein the driver has a thickness of 30 μm or more.   It is mounted directly on a flexible display panel, or mounted on a flexible printed circuit (FPC) having flexibility, and then mounted on the flexible display panel via a flexible printed circuit (FPC). 2. The flexible driver IC according to 2.   4. The flexible driver IC according to claim 3, wherein an anisotropic conductive adhesive is used for direct mounting on a flexible display panel or mounting on a flexible printed circuit. At least one kind of display medium composed of at least one kind of particles and having optical reflectivity and chargeability is enclosed in a space between two opposing flexible substrates, at least one of which is transparent, and an electric field is contained in the display medium. 5. The flexible driver IC according to claim 1, wherein the flexible driver IC is mounted on a flexible display panel that displays information such as an image by moving a display medium.

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