JP4572533B2 - Front plate for electrophoretic display device, its inspection method and inspection device - Google Patents

Description

  The present invention relates to a front plate for an electrophoretic display device, an inspection method thereof, and an inspection device.

  As a technique for realizing an electrophoretic display device having high visibility, rewritable and low power consumption, for example, an electronic paper display, various methods have been developed.

  A display device using an electrophoretic phenomenon uses a phenomenon in which charged particles move in a solvent by applying an electric field. As one of the technologies, a microcapsule type electrophoresis system has been put into practical use. In this microcapsule type electrophoresis method, positively and negatively charged white particles and black particles are accommodated in a microcapsule filled with a transparent solvent, and each particle is pulled up to the display surface by application of an external voltage. Is formed.

  Since the size of the microcapsule is as small as several tens μm to several hundreds μm, when the microcapsule is dispersed in a transparent binder, it can be coated on a substrate like an ink. This ink is called electronic ink because an image can be drawn by applying a voltage from the outside. An active matrix display panel can be formed by coating the electronic ink on a transparent film on which a transparent electrode is formed and bonding the electronic ink to a substrate having an electrode circuit for driving an active matrix.

  Here, a part in which electronic ink is coated on a film in which a transparent electrode is formed on a transparent film is referred to as a “front plate”, and a substrate on which an electrode circuit for active matrix driving that is joined to the front plate is formed is referred to as a “back plate”. It is called “face plate”.

  Various defects occur in the front plate, but if the defect inspection is performed after the front plate and the back plate are bonded together, the loss of the expensive back plate must be discarded due to the failure of the front plate. Occurs. Therefore, it is desired to perform defect inspection at the component stage of each of the front plate and the back plate. As a defect inspection method using such an image, for example, a method disclosed in Patent Document 1 is known.

  However, when performing a defect inspection of the front plate, there is a problem that an electrode for applying a voltage to the microcapsule is only on one side. Therefore, a flat electrode is provided on the inspection apparatus side, and the front plate is brought into close contact with each other, and a voltage is applied between the transparent electrode of the front plate, thereby moving particles in the microcapsule and making the front plate completely white. It is conceivable to check whether all the microcapsules can be driven normally in the two states of the entire surface black.

  In that case, in order to place the front plate on the planar electrode of the inspection apparatus and bring them into close contact, it is necessary to press the front plate from above. At this time, since the front plate is imaged by a camera or the like from the upper surface, it is conceivable to use a transparent glass plate or the like for the pressed portion. In addition, when a part of air remains between the planar electrode and the front plate, the voltage applied to the microcapsules in that portion is reduced, and normal microcapsules are not normally operated. Therefore, in order to avoid this, it is conceivable that the degree of adhesion is increased by evacuation.

  However, due to the evacuation, a very thin air layer is partially generated between the glass on the upper surface and the front plate, where interference fringes are generated due to the light interference phenomenon. This interference fringe hinders defect inspection.

Due to the above problems, until now, the inspection of the front plate has been carried out by extracting a part of the product and bonding it to the back plate or the flat electrode, with the electrodes on both sides of the microcapsule. However, this is a destructive inspection, and there is a loss that the front plate used for the inspection cannot be used for the product.
JP 07-306160 A

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its purpose is to provide a front panel for an electrophoretic display device capable of performing non-destructive defect inspection of the front panel, which is difficult because the electrode is only on one side. An inspection method and an inspection apparatus are provided.

In order to solve the above problems, the present invention comprises a transparent electrode, a display layer, and a release sheet that are sequentially laminated on a transparent substrate, and the release sheet has a conductive layer and a release layer on one surface of a substrate. And a part of the laminate of the release sheet substrate and the conductive layer, wherein a part of the transparent electrode protrudes laterally to form a first inspection electrode. Projecting sideways to form a second inspection electrode , the release sheet is delaminated between the release layer and the adhesive layer to expose the adhesive layer, and other electrodes and driving elements on another substrate A front plate for an electrophoretic display device for constituting a display device by being attached to a back plate comprising

  In addition, as a release film, what laminated | stacked the conductive layer on support films, such as a polyester film, can be utilized, but this release film is bonded together so that a conductive layer may contact the said adhesive layer directly. It is desirable that

  If a support film such as a polyester film is laminated so as to contact the adhesive layer, the support film is interposed between the conductive layer and the adhesive layer, and it is necessary to apply a high voltage for inspection. Arise. For example, when a polyester film is used as the support film, a voltage of 15 to 20 V is only applied to the display material even if a high voltage of about 600 V is applied between the conductive layer and the adhesive layer. . For this reason, not only the inspection becomes inefficient, but also discharge may occur from the edge portion of the front plate where electric charges tend to collect, and it becomes difficult to prevent work safety and quality deterioration of the front plate. On the other hand, when the conductive layer is laminated so as to be in direct contact with the adhesive layer, the adhesive layer is generally very thin, so that a substantial voltage drop does not occur. If a voltage of 15 to 20 V is applied between the two, the voltage is applied to the display material as it is. For this reason, it is safe in work and there is no fear of quality deterioration of the front plate.

  In addition, when the present invention is applied to the front plate of a display device using an electrophoretic phenomenon, if the conductive layer is pasted so as to be in direct contact with the adhesive layer, a voltage is applied once and the display is performed. For example, after the screen is displayed in white or black, the display state is maintained as it is even if the voltage application is stopped. For this reason, it is possible to take an image of the maintained display screen after removing a probe or the like applied to voltage application, thereby enabling a more accurate inspection.

  From the circumstances as described above, the release film is composed of a base material and a conductive layer bonded to the base material, and the conductive layer side of the release film is bonded to the adhesive layer via the release layer. It is desirable to do. In addition, as a peeling layer, there exists a silicone layer etc. which are used when peeling a peeling film, Generally, it is provided thinly to such an extent that a voltage drop does not arise.

  In the front plate of the present invention, the display layer can be a microcapsule type display layer including black particles, white particles, and microcapsules containing a dispersion medium in which these particles are dispersed.

In the present invention, a voltage for driving the display layer is applied between the first inspection electrode and the second inspection electrode of the front plate described above to display an image on the display layer, There is provided a method for inspecting a front plate for an electrophoretic display device, wherein the display image is inspected.

Furthermore, the present invention is an apparatus for inspecting a front plate for an electrophoretic display device for inspecting the front plate described above, the first probe being in electrical contact with the first inspection electrode, the first probe A second probe in electrical contact with two inspection electrodes, and the display layer between the first inspection electrode and the second inspection electrode via the first and second probes. Provided is a front plate inspection apparatus for an electrophoretic display device, comprising voltage supply means for applying a driving voltage and image inspection means for inspecting an image displayed on the display layer .

  The present invention also provides a method for inspecting a front plate, in which a voltage for driving the display layer is applied between the electrode of the front plate and the conductive layer described above to inspect the display layer for display defects. The voltage for driving the layer includes a pulse voltage for setting the display layer in a white state, a pulse voltage for setting the display layer in a black state, and a transition state in the middle of the display layer from the white state to the black state or from the black state to the white state. A front plate inspection method is provided, in which each state is imaged by an area camera, and the obtained image signal is image-processed to inspect the display layer for display defects. To do.

Furthermore, the present invention is, above-described a test device of the electrophoretic display device front plate for the front plate to inspection, a first probe in electrical contact with the first inspection electrode, A second probe in electrical contact with the second inspection electrode; and the display between the first inspection electrode and the second inspection electrode via the first and second probes. An inspection device for an electrophoretic display device front plate comprising voltage supply means for applying a voltage for driving a layer and image inspection means for inspecting an image displayed on the display layer, wherein the voltage supply means pulse voltage to the display layer and the white state, a pulse voltage to the display layer and the black state, and a pulse voltage to transition state in the middle of the white state from the middle or the black state of the black state the display layer from white state applied to the image checking unit, the white state Black state, and provides an area camera for imaging each state transition state, the inspection device of the electrophoretic display device front plate, characterized in that it comprises a means for processing an image signal obtained by the area camera To do.

  According to the front plate, the front plate inspection method, and the inspection apparatus according to the present invention configured as described above, the release film provided on one surface of the front plate before constituting the display device has a conductive layer. Therefore, a voltage is applied between the electrode on the front plate and the conductive layer to drive the display layer, for example, to display the entire surface white or the entire surface black, and use the camera and image processing means to The face plate can be inspected for defects. For this reason, non-destructive and no interference fringes are generated due to the light interference phenomenon, and it is possible to perform defect inspection with high accuracy.

  Further, in the method for inspecting a front plate according to the present invention, after applying a voltage for driving the display layer between the transparent electrode and the conductive layer to display an image on the display layer, the voltage application is stopped. Thus, it is possible to hold the image display state of the display layer for a predetermined time, and during that time, by inspecting the display image, it is possible to inspect with higher accuracy.

  Further, according to the method and apparatus for inspecting a front plate according to the present invention, a white state, a black state, and a transition state from the white state to the black state or from the black state to the white state are displayed, and the area is displayed. Compared with conventional inspection methods, application of pulse voltage for gray display state can be omitted by capturing images with a camera and processing the obtained image signals to inspect for display defects. In addition, the use of an area camera can significantly reduce the inspection time.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, the configuration of a display to which the front plate according to the present invention is applied will be described.

  As a display material used for a display to which the front plate according to the present invention is applied, a material capable of displaying an image depending on whether or not a voltage is applied or the direction of the applied voltage can be used. Preferably, the display has a sufficient contrast even when there is no backlight. Examples of such display materials include electroluminescent materials, polymer-dispersed liquid crystals (PDLC), polymer-stable liquid crystals, smectic liquid crystals, ferroelectric liquid crystals, and microcapsule-type electronic inks. Among these, electronic ink can be preferably used, and by using electronic ink, it is possible to display an image close to conventional paper.

  Hereinafter, a display using the microcapsule type electronic ink will be described in detail.

  A cross-sectional view of the display 41 is shown in FIG. In FIG. 12, an electrode film 41d, an image display layer 41c, an electrode film 41b, and a surface protective layer 41a are laminated on a substrate 41e made of a material having a supportability such as paper or plastic.

  In the configuration shown in FIG. 12, the structure in which the electrode film 41d is formed on the substrate 41e corresponds to the back plate, and the structure in which the image display layer 41c is formed on the transparent electrode film 41b corresponds to the front plate. The surface protective layer 41a can be omitted.

  The electrode film 41b is formed by forming a transparent electrode on a transparent plastic film (transparent substrate) having excellent dimensional stability, such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyimide. The electrode film 41d is also formed by forming a similar base electrode, but transparency is not necessarily required.

  Any electrode method can be selected. However, when the microcapsule electrophoresis method is used, the electrode film 41b is a common electrode having the same potential on the entire surface, and the electrode film 41d includes an active matrix electrode and a segment. By using electrodes such as electrodes, different potentials can be obtained for each pixel.

  Next, a configuration when electronic ink is used for the image display layer 41c will be described.

  An example of the microcapsule 110 in the electronic ink is shown in FIG. The microcapsule 110 has a capsule shell 111 made of methacrylic acid resin, urea resin, gum arabic, or the like. Inside, white particles 113 made of titanium oxide and black particles 114 made of carbon black are highly viscous such as silicone oil. The dispersion medium 112 is encapsulated in a dispersed state. White particles of titanium oxide are positively charged, while black particles of carbon black are negatively charged.

  For this reason, as shown in FIG. 14B, when an electric field is applied to the two electrode films 41b and 41d, the electrode film 41b becomes a negative electrode and the electrode film 41d becomes a positive electrode, positively charged white particles Since 113 is drawn to the electrode film 41b side and black particles 114 are drawn to the electrode film 41d side, at least the electrode film 41b is set as a transparent electrode, and when observed from above the electrode film 41b side, the portion looks white.

  Conversely, when the electrode film 41b is a positive electrode and the electrode film 41d is a negative electrode, positively charged white particles 113 are drawn to the electrode film 41d side, and black particles 114 are drawn to the electrode film 41b side. When observed from above the film 41b, the portion looks black.

  The image display layer 41c has a large number of such microcapsules 110. By controlling the electric field of each address electrode of the electrode films 41b and 41d, the letter “A” in FIG. As displayed, a desired character or figure can be displayed with white and black pixels.

  In the above example, the microcapsule is a monochrome (black and white) display containing two types of black and white particles, but by adjusting the position of the particles in multiple steps by applying the potential, It is possible to display, color display by containing particles of different colors, or two or more kinds of particles.

  The above microcapsules contain two types of black and white particles, but monochrome (black and white) display can also be realized by using one type of particles and coloring the dispersion medium to black.

  That is, as shown in FIG. 15, an electric field is applied to the two electrode films 41b and 41d by using microcapsules in which titanium oxide as white particles is positively charged and dispersed in a dispersion medium 115 colored in black. When the electrode film 41b becomes the negative electrode and the electrode film 41d becomes the positive electrode, the positively charged white particles 113 are drawn to the electrode film 41b side, and the dispersion medium 115 colored black is inevitably. Since it is pushed down to the side, the part looks white when observed from above the electrode film 41b side. Conversely, when the electrode film 41b is a positive electrode and the electrode film 41d is a negative electrode, the positively charged white particles 113 are drawn toward the electrode film 41d, and the dispersion medium 115 colored black is inevitably generated. Since it is pushed up to the side, when viewed from above the electrode film 41b side, the portion looks black.

  When the microcapsule is driven by the active matrix driving method, the electrode film 41d is independently patterned for each pixel as a pixel electrode, and is provided with a thin film transistor, a signal electrode, and a scanning electrode (not shown), and the electrode film 41b is light transmissive. A transparent common electrode is formed uniformly on the substrate. In this case, if the electrode film 41b is a common electrode, the entire surface has the same potential. Therefore, by controlling the electric field of each address electrode on the electrode film 41d side, the particles in the microcapsule at the electrode position can be moved based on the above principle. A desired image can be displayed.

  Similarly, the electrode film 41d is used as a common electrode (the potential is set to zero), and the electric field of each address electrode on the electrode film 41b side is controlled (giving a positive or negative potential), so that the inside of the microcapsule at the electrode position A desired image may be displayed by moving the particles.

  In the case of time-division driving, the electrode films 41b and 41d are composed of transparent electrodes made of transparent conductors such as linear ITO (Indium Tin Oxide) that are orthogonal to each other, and microcapsules are placed in the region where both electrodes intersect. Form.

  Of course, the driving method is not limited to that described above, and an optimal driving method may be selected according to the application.

  Various diameters of the microcapsules can be employed, but sufficient resolution and responsiveness can be obtained by adopting a diameter of about 40 μm to about 100 μm. The resolution of the displayed image mainly depends on the arrangement (resolution) of the electrode in the electrode film. However, if the diameter of the microcapsule is small, the moving speed of the microcapsule in the dispersion medium increases, and as a result, the response at the time of display is increased. There is an advantage that it is excellent (response speed is fast).

  The above example is an example of monochrome (black and white) image display, but as shown in FIG. 16, a color having R (red), G (green), and B (blue) colors divided in units of pixels. By providing the filter 41f on the side of the transparent electrode film 41b to which an electric field can be applied in pixel units, it is possible to realize color image display.

  That is, the observation light of the portion where the white particles are drawn to the electrode film 41b side is reflected by the white particles and passes through the color filter, so that the color of the color filter is observed.

  In the example of FIG. 16, since R particles and G pixels of the color filter have white particles drawn to the transparent electrode side of the electrode film 41b, R light and G light are observed, and the B pixel portion of the color filter is Since the black particles are drawn to the transparent electrode side of the electrode film 41b, the observation light is absorbed and the B light is not observed. In this way, color image display is possible by controlling the R, G, B light observed in pixel units. In FIG. 16, the electrode 41d is a common electrode, but the electrode 41b side may be a common electrode.

  A paper-like electronic display is made of a material having a supportability, and patterning of electrodes and the like can be formed on a plastic film by a printing method or a vapor deposition method. The display screen size can be created in any size according to the application and demand. In addition, since it is manufactured using a film, it is a light display medium that is not bulky and can be suitably used as the display medium of the present invention.

  In the image display layer 41c, there is no problem in display even if the position of the microcapsules 110 varies slightly. Therefore, it is possible to bend and use it by attaching it to a curved surface.

  Each particle is dispersed in a highly viscous dispersion medium, and once the electric field is applied, the position of the particle does not change even when the power is turned off. In this way, the display image does not disappear even when the display is turned off. It has non-volatility (memory property), so it is only necessary to apply an electric field at the time of initial display or rewriting, and it is necessary for display compared to a normal display device. It requires less power and can save a lot of power.

  Further, in the display 41, there is no problem in display even if the position of the microcapsule 110 is slightly changed. Therefore, by using a material that makes the entire display 41 including the electrode sheets 41b and 41d thin and portable, flexibility such as paper can be provided.

  Further, since the carbon black of the black particles 114 is the same material as the ink for performing normal printing, it is possible to perform a natural display that is very close to a printed matter on paper.

Hereinafter, various embodiments of the present invention will be described.
FIG. 2 shows a cross-sectional view of the front plate 1 before constituting a display according to the first embodiment of the present invention. In this figure, since it is not yet bonded, an unnecessary release layer 16 and release film 17 are provided in the display state.

  That is, the front plate 1 has a configuration in which a transparent electrode 13, electronic ink 14, an adhesive layer 15, a release layer 16, and a release film 17 are sequentially laminated on a transparent base film 12. The release film 17 is formed by laminating a conductive layer 18 on a support film 19.

  The front plate 1 configured as described above is separated between the adhesive layer 15 and the release layer 16 in a later assembly process, and the release film 17 is removed together with the release layer 16. Affix to the face plate.

  Examples of the release film 17 include a support film 19 made of a thermoplastic film such as a polyethylene terephthalate film, and the like, in which a conductive layer 18 such as an ITO vapor deposition layer or an aluminum vapor deposition layer is laminated. The film which laminated | stacked is preferable.

The release film 17 is positioned so that the aluminum vapor deposition layer 18 faces outward. The thickness of the aluminum vapor deposition layer 18 is preferably 50 to 300 μm.
As the release layer 16, a silicone resin or the like can be used.

  Here, as shown in FIG. 2, a part of the structure in which the transparent electrode 13 is formed on the transparent base film 12 protrudes to the side, and a part of the transparent electrode 13 is exposed to the outside. A pair of probes 2 and 3 are in contact with this portion and the lower surface of the conductive layer 18, and a voltage is applied to both from the drive voltage generator 6 to cause electrophoresis of particles in the microcapsules of the electronic ink 14. The front plate can be displayed in white or black.

  The front plate inspection method and inspection apparatus shown in FIG. 2 will be described below.

  FIG. 1 shows a schematic configuration of a front plate inspection method according to a first embodiment of the present invention. The front plate 1 is placed on the inspection plate 4 of the inspection apparatus. The inspection plate 4 is made of an insulating resin material, and the probe 2 and the probe 3 incorporating springs are attached to the inspection plate 4. The probe 2 and the probe 3 are electrically connected to the transparent electrode 13 and the conductive layer 18 of the front plate 1 by lowering the glass plate 5 in parallel by an air cylinder or an electric motor drive from above the front plate 1. Contact.

  Here, by applying a driving voltage between the electrodes from the driving voltage generator 6, the particles in the microcapsules of the electronic ink 14 are moved to display the entire surface white or the entire surface black, and the camera 8 50 × An image is captured with an image accuracy of about 50 μm / pixel, the image is sent to the control device 7 as digital data, and defect inspection is performed. The voltage applied between both electrodes is usually about several hundred volts.

  In addition, since the defect inspection is performed with the entire surface of the front plate 1 being white or black, the defect inspection method using an image is disclosed in Patent Document 1 described above, which is known as a defect inspection technique for plain sheets such as paper and film. The described technology can be used. The defect accuracy in this case is determined as a defect when an image area other than white or black having a diameter of 100 μm or more is recognized, and display is performed.

  Next, FIG. 4 shows a cross-sectional view of the front plate 1 before constituting the display according to the second embodiment of the present invention. Also in this figure, a release layer 16 and a release film 17 that are removed before the display is completed are provided.

  The difference between the front plate 1 shown in FIG. 4 and the front plate 1 shown in FIG. 2 is the order of lamination of the release films 17. That is, in the front plate 1 shown in FIG. 4, the release film 17 is bonded to the inner side of the aluminum vapor deposition layer, that is, in such a direction that the aluminum vapor deposition layer 18 directly adheres to the adhesive layer 15 via the release layer 16.

  Here, as shown in FIG. 4, as in the structure shown in FIG. 2, a part of the structure in which the transparent electrode 13 is formed on the transparent base film 12 protrudes to the side, and a part of the transparent electrode 13 is While there is a portion exposed to the outside, a part of the release film 17 in which the aluminum vapor deposition layer 18 is formed on the support film 19 protrudes to the side, and a portion where the aluminum vapor deposition layer 18 is exposed to the outside is there. Probes are in contact with the exposed portions of the transparent electrode 13 and the aluminum vapor deposition layer 18, respectively, and a voltage is applied from a power source to cause electrophoresis of particles in the microcapsules of the electronic ink 14, and the front plate is entirely white or black. Can be displayed.

  As shown in FIG. 4, according to the structure in which a part of the release film 17 protrudes to the side, the protruding part serves as a peeling margin, and there is an advantage that the release film 17 can be easily peeled off. .

  The front plate inspection method and inspection apparatus shown in FIG. 4 will be described below.

  FIG. 3 shows a schematic configuration of a front plate inspection method according to the second embodiment of the present invention. The front plate 1 is placed on the inspection plate 4 of the inspection device. The inspection plate 4 is made of an insulating resin material or the like. A probe 2 and a probe 3 incorporating springs are attached to the inspection plate 4. The probe 2 and the probe 3 are electrically connected to the transparent electrode portion 13 and the conductive layer 18 of the front plate 1 by lowering the glass plate 5 from above the front plate 1 in parallel by an air cylinder or an electric motor drive. Contact

  Here, by applying a drive voltage from the power source 6 between the electrodes, the particles in the microcapsules of the electronic ink 14 are moved to display the entire white or the entire black, and the camera 8 is 50 × 50 μm / pixel. The image is picked up with a degree of image accuracy, and the image is taken into the control device 7 as digital data to perform defect inspection. The voltage applied between both electrodes may be about 10-20V. In addition, when the present invention is applied to the front plate of the display using the electrophoretic phenomenon, once the voltage is applied and the display screen is, for example, full white display or black display, the voltage application is stopped, The display state is maintained as it is. For this reason, it is possible to image the maintained display screen after removing the probe or the like applied to the voltage application.

  Since the defect inspection is performed with the entire surface of the front plate 1 being white or black, the defect inspection method using images is known as a defect inspection technique for plain sheets such as paper and film. The technique described in 1 can be used. The defect accuracy in this case is determined as a defect when an image area other than white or black having a diameter of 100 μm or more is recognized, and display is performed.

  Further, for the front plate determined to be a non-defective product as a result of the inspection, the release layer 16 and the release film 17 are removed in the subsequent process, and are bonded to the back plate by the adhesive layer 15. In the present invention, a conductive film is used for the release film 17. The release film 17 includes an ITO vapor-deposited film using polyethylene terephthalate as a support film, an aluminum vapor-deposited film, and the like, but an aluminum vapor-deposited film is preferable in terms of cost. The aluminum vapor deposition surface 18 is bonded in such a direction as to be inside. Moreover, as the thickness, 50-300 micrometers is preferable.

  FIG. 5 shows the voltage waveform used in the front plate inspection method according to the third embodiment of the present invention, the optical response of the front plate corresponding thereto, and the imaging timing. In this embodiment, a display layer in which a black state is displayed by applying a positive voltage pulse and a white state is displayed by applying a negative voltage pulse is used.

  As shown in FIG. 5, in the front plate inspection method according to the present embodiment, when a black state is displayed by applying a positive voltage pulse, the connection between the drive voltage supply device and the electrodes on the front plate is cut off. The drive voltage supply device is composed of the drive voltage forming device 6 and the probes 2 and 3 in the device shown in FIG.

  In this state, the black state is maintained for a certain period, and a black display image is captured within this period. Next, when a white state is displayed by applying a negative voltage pulse, the connection between the drive voltage supply device and the electrode on the front plate is cut off. In this state, the white state is maintained for a certain period, and a white display image is captured within this period. Next, a positive voltage pulse is applied, but since the pulse length of this positive voltage pulse is short, all the particles in the microcapsule do not move, and only some particles move, so a gray state is displayed. Is done. At this time, the connection between the drive voltage supply device and the electrode on the front plate is cut off. In this state, the gray state is maintained for a certain period, and a gray display image is captured within this period.

Note that if 0 V is applied without interrupting the connection between the drive voltage supply device and the electrodes on the front plate, the display state is not maintained and changes.
In this way, each image is picked up and inspected for the presence of defects on the front plate. Examples of defects on the front plate include defects that are conspicuous in the white state, missing of electronic ink (microcapsules), microcapsules that are not driven (dead microcapsules), and defects that are conspicuous in the black state such as laminate There is foreign matter mixed in in the process.

  In this way, displaying and capturing images in each state is because defects that could not be detected in a certain state can be detected in different states, so it is necessary to perform a defect inspection in each display state. Because there is.

  A specific defect can be detected as follows, for example.

  That is, first, a sample with a known reflectance, for example, a printed matter (sample) printed with black ink is imaged, and a calibration equation for the gradation value and reflectance of the imaging camera is created in advance. And each display image of the black state of the front plate, a white state, and a gray state is imaged, and the histogram average value of a measurement area is obtained about each gradation value. Then, these values are substituted into the calibration equation, and the reflectances in the black state, white state, and gray state are calculated.

  In this case, defect reflectances in the black state and the white state are set, and NG is set when the reflectance in the black state is a predetermined value or more, and NG when the reflectance in the white state is a predetermined value or less.

Next, the contrast ratio is obtained from the reflectance in the white state / the reflectance in the black state. Then, a defect contrast ratio is set, and NG is set when the contrast ratio is a predetermined value or less. Note that when there is a defect in the electrode portion instead of the display layer, the front plate is not driven, and the reflectance in the white state and the reflectance in the black state are the same, so the contrast ratio is 1. Thus, it is possible to know the reason for the NG determination from the contrast ratio.
The procedure for obtaining the reflectance and contrast ratio as described above is shown in the block diagram of FIG.

  Next, FIG. 8 shows a cross-sectional view of the front plate 1 before constituting a display according to the fourth embodiment of the present invention. Also in this figure, a release layer 16 and a release film 17 that are removed before the display is completed are provided. The configuration of the release film 17 is the same as that of the release film 17 of the front plate 1 shown in FIG.

  Here, as shown in FIG. 8, there are a part of the front plate 1 where the transparent electrode 13 is exposed to the outside and a part where the aluminum vapor deposition layer 18 is exposed to the outside. Are contacted and a voltage is applied from the power supply, the particles in the microcapsules of the electronic ink 14 can be electrophoresed, and the front plate can be brought into a display state of full white or full black.

  The front plate inspection method and inspection apparatus shown in FIG. 8 will be described below.

  As described above, in the present invention, the release film of the adhesive layer provided on the back side of the front plate for bonding to the back plate is a conductive film, the conductive release film is used as an electrode, and the front side By applying a voltage to the transparent electrode, the particles in the microcapsule are moved, and the front plate is made into three states of white, black, and gray, and all the microcapsules can be driven normally. Can be inspected.

  Here, even when the front plate is for black and white binary electronic paper, it is desirable to perform inspection in a gray state. This is to detect microcapsules with a slow response speed that are difficult to find in the white or black state. In the white state and the black state, a voltage is applied for a predetermined pulse length, while the gray state is realized by applying a voltage for a shorter pulse length.

  As described above, in order to perform inspection in the three states of white, black, and gray, a sequence of white pulse application, imaging, black pulse application, imaging, gray pulse application, and imaging is required. In addition, since it is necessary to image the entire surface of the front plate with a high resolution of about 50 × 50 μm / pixel, a line camera is used, so a scanning time for imaging the entire surface of the front plate is also required, and inspection time is required. There is a problem of becoming longer.

This problem can be solved by the front plate inspection method and apparatus according to the fourth embodiment of the present invention as described below.
FIG. 7 shows a schematic configuration of a front plate inspection method according to a fourth embodiment of the present invention. In the inspection apparatus shown in FIG. 7, a control unit 21 is configured by the drive voltage generation device 6 and the image processing device 7, and an area camera 22 is disposed above the front plate 1.

  Since the front plate 1 has a portion where the transparent electrode 13 and a part of the aluminum vapor deposition layer 18 are taken out to the outside, the probes 2 and 3 of the inspection device are brought into contact with this to drive the control unit 21 of the inspection device. A drive waveform generated by the voltage generator 6 is applied. Depending on the waveform, the particles in the microcapsules of the electronic ink 14 move to the front and back surfaces, and the surface of the front plate 1 changes to white and black.

  At the timing synchronized with the drive waveform generated by the drive voltage generator 6, the entire surface of the front plate 1 is divided by the area camera 22 and imaged at a time with an image accuracy of about 50 × 50 μm / pixel. The captured image is sent as digital data to an image processing apparatus and processed for defect inspection.

  In the example shown in FIG. 7, 24 currently 4 × 6 area cameras of 1 million pixel class are arranged side by side, and images are taken up to a maximum front plate size of 200 × 300 mm with a resolution of 50 × 50 μm / pixel.

  Since the defect inspection is performed with the entire surface of the front plate 1 being white or black, the defect inspection method using images is known as a defect inspection technique for plain sheets such as paper and film. The technique described in 1 can be used. The defect accuracy in this case is determined as a defect when an image area other than white or black having a diameter of 100 μm or more is recognized, and display is performed.

Here, driving waveforms and imaging timing will be described.
First, a method using a line camera as an imaging device is shown in FIG. In FIG. 9, the driving waveform is shown on the upper side and the imaging timing is shown on the lower side. A positive voltage pulse 25 is applied to bring the front plate 1 into a white state, and imaging is performed at the imaging timing 28. Similarly, the negative voltage pulse 26 is applied to bring the front plate 1 into a black state, and imaging is performed at the imaging timing 29. Finally, the positive voltage pulse 27 is applied to bring the front plate 1 into a white state, and imaging is performed at the imaging timing 30. The difference between the positive voltage pulses 25 and 27 is the pulse length. When the pulse length is long, all the particles in the microcapsule move. On the other hand, when the pulse length is short, some of the particles in the microcapsule move. As a result, white and gray can be realized.

  As described above, in the method illustrated in FIG. 9, imaging is performed after applying each pulse for setting each of the white, black, and gray states. Since imaging needs to be performed on the entire surface of the front plate with a high resolution of 50 × 50 μm / pixel, a line camera is used. Therefore, in order to image the entire surface of the front plate, it is necessary to move the camera or the front plate, which increases the imaging time.

  For example, when a maximum front panel size of 200 × 300 mm is imaged at a resolution of 50 × 50 μm / pixel with a line camera of 400 pixels and 20 MHz drive, it takes about 1.2 seconds, so each state of white, black, and gray Then, 3.6 seconds are required only for imaging.

  On the other hand, the imaging timing according to the inspection method of the present invention is shown in FIG. At this imaging timing, a gray-state imaging timing 33 is provided in the middle of the positive voltage pulse 31, and a white-state imaging timing 34 is provided at the end of the positive voltage pulse 31. The negative voltage pulse 32 and the black state imaging timing 35 are the same as in the conventional case.

  When the change in the reflection intensity of the front plate with respect to the drive pulse in the case of imaging at the imaging timing shown in FIG. 10 was obtained, the result shown in FIG. 11 was obtained. In FIG. 11, the reflection intensity is shown on the upper side, and the drive waveform is shown on the lower side. As shown in FIG. 11, the movement of particles starts simultaneously with the rise of the pulse, white particles gather on the display surface, and the reflection intensity of the front plate increases. Since the gray pulse corresponds to returning the voltage to 0 V in the middle, if an image at this moment is taken, an equivalent image at the time of applying the gray pulse can be obtained.

  In the imaging timing method according to the inspection method according to the fourth embodiment of the present invention, the time lapse corresponding to the conventional gray pulse 27 is applied when the white pulse is applied, using the feature of the area camera that completes imaging in a short time. By treating an image captured later as a gray image, it is not necessary to apply a gray pulse. In the area camera, since the imaging time in each state is 33 ms, the total imaging time is 66 ms. Since gray is applying a white pulse, the imaging time can be regarded as 0 ms.

  In addition, this invention is not limited to the said embodiment and Example, A component can be deform | transformed and embodied in the range which does not deviate from the summary in an implementation stage. In addition, various inventions can be configured by appropriately combining a plurality of constituent elements disclosed in the above embodiments and examples. For example, some constituent elements may be deleted from all the constituent elements shown in the embodiments and examples, and the constituent elements in different embodiments and examples may be appropriately combined.

The figure which shows schematic structure of the inspection method of the front plate which concerns on 1st Example of this invention. Sectional drawing which shows the front board which concerns on the 1st Example of this invention. The figure which shows schematic structure of the inspection method of the front plate which concerns on the 2nd Example of this invention. Sectional drawing which shows the front board which concerns on the 2nd Example of this invention. The figure which shows the voltage waveform used with the test | inspection method of the front plate which concerns on 3rd Example of this invention, the optical response of the front plate corresponding to it, and an imaging timing. The block diagram which shows the procedure which calculates | requires the reflectance and contrast ratio in the inspection method of the front plate which concerns on the 3rd Example of this invention. The figure which shows schematic structure of the inspection method of the front plate which concerns on the 4th Example of this invention. Sectional drawing which shows the front board which concerns on the 4th Example of this invention. The figure which shows the drive waveform and timing of imaging in the method using a line camera. The figure which shows the timing of the imaging which concerns on the test | inspection method of the front plate which concerns on the 4th Example of this invention. The figure which shows the change of the reflection intensity of the front plate with respect to the drive pulse at the time of imaging with the imaging timing shown in FIG. Sectional drawing which shows the display apparatus using the front plate which concerns on one Embodiment of this invention. Sectional drawing which shows the outline of the microcapsule used for the front plate which concerns on one Embodiment of this invention. The perspective view explaining the drive state and display state of the microcapsule used for the front plate concerning one embodiment of the present invention. The perspective view explaining the drive state of the microcapsule different from the microcapsule shown in FIG. Sectional drawing explaining the color display by the drive state of the microcapsule used for the front plate which concerns on one Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Front plate, 2 ... Transparent electrode probe, 3 ... Conductive film probe, 4 ... Inspection plate, 5 ... Glass plate, 6 ... Drive voltage generator, 7 ... Control device, 8 ... Camera, 12 ... Base transparent film, 13 ... Transparent electrode, 14 ... Electronic ink, 15 ... Adhesive layer, 16 ... Peeling layer, 17 ... release film, 18 ... conductive layer, 19 ... support film, 41 ... display, 41b ... electrode film, 41d ... electrode film, 41e ... substrate, 41f ... Color filter, 42 ... Image display layer, 43 ... Base material, 44 ... Common electrode, 45 ... External electrode, 110 ... Microcapsule, 111 ... Capsule shell, 112 ... Dispersion medium, 113 ... white particles, 114 ... black Child, 115 ... colored dispersion medium.

Claims (10)

A transparent electrode, a display layer, and a release sheet are sequentially stacked on a transparent substrate, and the release sheet is formed by sequentially stacking a conductive layer, a release layer, and an adhesive layer on one surface of a substrate. A part of the transparent electrode protrudes to the side to form a first inspection electrode, and a part of the laminate of the base material and the conductive layer of the release sheet protrudes to the side to perform the second inspection. An electrode is formed, and the release sheet is delaminated between the release layer and the adhesive layer to expose the adhesive layer, and is attached to a back plate having other electrodes and driving elements on another substrate for display. A front plate for an electrophoretic display device for constituting the device. The front panel for an electrophoretic display device according to claim 1 , wherein the display layer is a microcapsule type display layer including black particles, white particles, and microcapsules containing a dispersion medium in which these particles are dispersed. Applying a voltage for driving the display layer between the first inspection electrode and the second inspection electrode of the front plate according to claim 1 or 2 to display an image on the display layer, A method for inspecting a front plate for an electrophoretic display device, wherein the display image is inspected. After applying a voltage for driving the display layer between the first inspection electrode and the second inspection electrode to display an image on the display layer, the application of the voltage is stopped, The method for inspecting a front plate for an electrophoretic display device according to claim 3 , wherein the display image is inspected in a state where the image display state of the display layer is maintained. The voltage for driving the display layer includes a pulse voltage for setting the display layer in a white state, a pulse voltage for setting the display layer in a black state, and a state in which the display layer is in the middle from a white state to a black state, or Including a transition voltage in the middle, and applying each pulse voltage to display each image on the display layer, the application of the voltage was stopped, and each image display state of the display layer was retained 5. The method for inspecting a front plate for an electrophoretic display device according to claim 3 , wherein each display image is inspected in a state. A voltage for driving the display layer is applied between the first inspection electrode and the second inspection electrode of the front plate according to claim 1 or 2 to display an image on the display layer. In the method for inspecting the front plate for inspecting the display image, the voltage for driving the display layer includes a pulse voltage for setting the display layer in a white state, a pulse voltage for setting the display layer in a black state, and the display layer Each of the displays includes a pulse voltage that is a transition state between a white state and a black state or a transition state between a black state and a white state. Each of the states is captured by an area camera and the obtained image signal is image-processed. A method for inspecting a front plate for an electrophoretic display device, comprising inspecting an image. An inspection apparatus for electrophoretic display devices front plate for testing the front plate according to claim 1 or 2, a first probe in electrical contact with the first inspection electrode, the second The display layer is driven between the first inspection electrode and the second inspection electrode via the first probe and the second probe, the second probe being in electrical contact with the inspection electrode . An apparatus for inspecting a front plate for an electrophoretic display device, comprising: voltage supply means for applying a voltage to be applied; and image inspection means for inspecting an image displayed on the display layer. The voltage supply means applies a voltage for driving the display layer between the first inspection electrode and the second inspection electrode conductive layer to display an image on the display layer. The electrophoretic display device according to claim 7 , wherein the image inspection unit inspects the display image in a state where the application of the voltage is stopped and thereby the image display state of the display layer is maintained. Front plate inspection device. The voltage supply means includes a pulse voltage for setting the display layer in a white state, a pulse voltage for setting the display layer in a black state, and a transition in the middle of the display layer from a white state to a black state or from a black state to a white state. After applying the pulse voltage to be in a state and displaying each image on the display layer, the application of the voltage is stopped, thereby holding each image display state of the display layer, and the image inspection means, The said display image is test | inspected, The inspection apparatus of the front plate for electrophoretic display apparatuses of Claim 7 or 8 characterized by the above-mentioned. An inspection apparatus for electrophoretic display devices front plate for testing the front plate according to claim 1 or 2, a first probe in electrical contact with the first inspection electrode, the second The display layer is driven between the first inspection electrode and the second inspection electrode via the first probe and the second probe, the second probe being in electrical contact with the inspection electrode . An inspection device for an electrophoretic display device front plate comprising voltage supply means for applying a voltage to be applied and image inspection means for inspecting an image displayed on the display layer, wherein the voltage supply means includes the display layer Applying a pulse voltage for setting the display layer to a white state, a pulse voltage for setting the display layer to a black state, and a pulse voltage for setting the display layer to a transition state from a white state to a black state or a black state to a white state, The image inspection means includes the white state, the black state, An area camera for taking each state of the fine transition state, the inspection device of the electrophoretic display device front plate, characterized in that it comprises a means for processing an image signal obtained by the area camera.

Images