JP2006023089A - Front plate defect measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus which does not malfunction due to the movement of particles in a microcapsule in a reverse direction to a direction in which the particles move when a voltage is rapidly impressed. <P>SOLUTION: An electrically conductive film is used as a separating film of a front plate to be used by separating the separating film. By impressing a driving voltage pulse for driving a display material between an electrode and the electrically conductive film, it is possible to inspect the presence or absence of a display defect prior to its bonding to a back plate. The front plate defect measuring apparatus comprises a driving voltage pulse impressing means for impressing a driving voltage pulse capable of achieving the largest contrast of a defective part; an imaging means for synchronously imaging at the compression of the impression of the driving voltage pulse; and a measuring means for measuring the size and contrast of the defective part by performing image processing on images imaged by the imaging means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an apparatus for measuring a defect size and contrast of a front plate, which is one of electronic paper display components.

  Various methods are being developed as technologies for realizing an electronic paper display having high visibility, rewritable characteristics and low power consumption. A display using an electrophoretic phenomenon uses a phenomenon in which charged particles in a solvent move by an electric field. As one of the techniques, a microcapsule type electrophoresis system has been put into practical use. In this method, positively and negatively charged white particles and black particles are placed in a microcapsule filled with a transparent liquid, and an image is formed by pulling up each particle to the display surface by applying an external voltage. Since the microcapsule size is as small as φ several tens μm to several hundreds μm, when the microcapsules are dispersed in a transparent binder, they can be coated like ink. This ink is called electronic ink because an image can be drawn by applying a voltage from the outside. When this electronic ink is coated on a transparent film on which a transparent electrode layer is formed and bonded to a substrate on which an electrode circuit for driving an active matrix is formed, an active matrix display panel can be formed. Here, a component 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 active matrix driving electrode circuit is formed is referred to as a “back plate”. Various defects occur in the front plate. However, if the defect inspection is performed after bonding the two together, there is a loss of discarding a normal product of the expensive back plate due to a defect in the front plate. Therefore, it is desired to perform defect inspection at the component stage of each of the front plate and the back plate.

  However, when performing a defect inspection of the front plate, each particle in the microcapsule is in a discrete state when no voltage is applied to the microcapsule, so the surface appears rough and gray, making it difficult to detect defects. It is. Therefore, it is necessary to apply a voltage to the microcapsule and find the defect in a white or black state on the entire surface, but the electrode for applying a voltage to the microcapsule is on one side in the state of the front plate alone before being bonded to the back plate. There is only a problem. Therefore, the release film of the adhesive layer on the back side of the front plate attached to the back plate is made a conductive film, this conductive release film is used as an electrode instead of the back plate, and the transparent electrode on the surface By applying a voltage between them, the particles in the microcapsule are moved, the front plate is made into three states of white, black, and gray, and all microcapsules can be driven normally. Is called.

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

  As described above, when the driving voltage is applied to the front plate and the defects found in the three states of white, black, and gray are detected as small dots of about several hundred μm, the display quality is improved when the final product is displayed. Since it has a great influence, its dimensions, contrast, and allowable number in the plane are clearly determined by the product specifications. For this reason, the detected defect requires a measuring device that strictly measures its size and contrast.

In order to measure them accurately until now, a driving voltage is applied to the front plate to make the defect easy to see, and then the front plate is removed from the drive and set in a device with a CCD camera attached to the microscope. An image of a part is taken into a computer and a dimension is measured by image processing. Due to the characteristics of the microcapsule electrophoresis method, the state of the microcapsule stays at the same position even after the drive voltage is cut. Therefore, a current flows between the electrodes sandwiching the microcapsule, and a phenomenon in which particles in the microcapsule rapidly move in a direction opposite to that when the voltage is applied is observed. For this reason, even if the dimension of the defect can be measured accurately, the state of the front plate changes during measurement, and the contrast of the defective part cannot be measured accurately.

  In addition, a general defect measuring device for a member for a display device is known which has an image pickup means for picking up an image with a camera in synchronization with the driving voltage pulse application represented by Patent Document 1, but the object is a liquid crystal display. This is a device and cannot be applied as it is to a display device having display memory characteristics such as the object of the present invention having the characteristics of the above-described microcapsule type electrophoresis system.

The patent literature is as follows.
JP 9-318487 A

  The present invention has been made in view of the above-mentioned problems, and the problem is that a drive voltage is applied to the front plate in order to measure the size of the defect detected by inspection and the contrast of the defective portion. An object of the present invention is to provide a front plate defect measuring apparatus characterized in that the image is captured by a camera in synchronization with the end of a driving voltage pulse in which the contrast of a defective portion increases, and the size and contrast of the defective portion are measured by image processing.

The present invention has been conceived in order to overcome the above-mentioned problems. At least the substrate, the electrode, the display material, the adhesive layer, and the peeling film on the front plate composed of the peeling film are peeled off, and at least from the substrate, the electrode or the driving element. In the display front plate formed by laminating the back plate, a conductive film is used as the peeling film of the front plate, and a driving voltage pulse for driving the display material is applied between the electrode and the conductive film. In the front plate defect measuring device for the front plate of the display, characterized in that the presence or absence of display defects can be inspected before being bonded to the back plate,
A driving voltage pulse applying means for applying a driving voltage pulse in which the contrast of the defective part is maximized;
Imaging means for imaging with a camera in synchronization with the end of application of the drive voltage pulse;
A measuring unit that performs image processing on the image captured by the imaging unit to measure the size and contrast of the defective portion;
It is intended to provide a front plate defect measuring device characterized by comprising:

According to the present invention, in front of a display formed by peeling off a release film on a front plate comprising at least a substrate, an electrode, a display material, an adhesive layer and a release film, and bonding a back plate comprising at least a substrate, an electrode or a drive element. In the face plate, by using a conductive film as a peeling film for the front plate, an electric signal for driving the display material can be applied to inspect the presence or absence of display defects before being bonded to the back plate. In the inspection of the front plate, in order to measure the size of the defect detected in the inspection and the contrast of the defective portion, a driving voltage is applied to the front plate, and in synchronization with the end of the driving voltage pulse where the contrast of the defective portion becomes the largest. A front panel defect measuring device characterized in that it measures the size and contrast of a defect by image processing with a camera. By use, in the conventional measurement method has enabled the contrast measurement of the defective portion could not be measured.

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

  First, the configuration of the display will be described.

  For display, a display having a sufficient contrast can be suitably used without a backlight. This is because electroluminescent materials, polymer-dispersed liquid crystals (PDLC), polymer-stable liquid crystals, smectic liquid crystals, ferroelectric liquid crystals, display devices using a microcapsule type electrophoresis system, etc. on a thin flexible substrate. It can be realized by combining. In particular, when a display body using a microcapsule type electrophoresis system is used, an image close to that of conventional paper can be displayed.

  The case where a film-type microcapsule type electrophoresis display is used as the display will be described in detail.

  A cross-sectional view of the display 41 is shown in FIG. An electrode film 41d, an image display layer 41c, an electrode film 41b, and a surface protective layer 41a for protecting the display portion are laminated on a flexible base material 41e such as paper or plastic.

  In this description, the base material 41e corresponds to the substrate described in the claims, the electrode film 41d corresponds to the electrode described in the claims, and the image display layer 41c corresponds to the display material described in the claims. The state in which the electrode film 41d and the image display layer 41c are provided on the base material 41e corresponds to the front plate described in the claims. The surface protective layer 41a can be omitted.

  The electrode film 41b is formed by forming an electrode on a transparent plastic film 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 following microcapsule electrophoresis method is used, the electrode film 41b is a common electrode to which the same potential is applied over the entire surface, and the electrode film 41d is active. An electrode such as a matrix electrode or a segment electrode can be employed.

  A configuration when the image display layer 41c is used in a microcapsule electrophoresis method will be described.

  An example of the microcapsule 110 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. It is dispersed and enclosed in a dispersion medium. White particles of titanium oxide are positively charged, while black particles of carbon black are negatively charged.

Therefore, as shown in FIG. 5B, when an electric field is applied to the two electrode films 41b and 41d so that 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 perform 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 black.

That is, as shown in FIG. 6, an electric field is applied to the two electrode films 41 b and 41 d by using microcapsules in which titanium oxide, which is white particles, is charged to a positive charge and dispersed in a black dispersion medium 115. Thus, when the electrode film 41b is a negative electrode and the electrode film 41d is a positive electrode, the positively charged white particles 113 are drawn to the electrode film 41b side, and the dispersion medium 115 colored in black is necessarily the electrode film of 41d. 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 line-shaped ITO (Indium Tin Oxide) that are orthogonal to each other, and microcapsules are placed in areas 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 adopted, but sufficient resolution and responsiveness can be obtained when a diameter of about 40 μm to about 100 μm is employed. 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 in the case of color image display, as shown in FIG. 7, R (red), G (green), and B (blue) divided into pixel units. ) Is provided on the transparent electrode film 41b side to which an electric field can be applied in pixel units.

  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. 7, 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 black. Since the 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, and B light observed in pixel units. In FIG. 7, 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 flexible material, 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 flexible, it is possible to provide flexibility such as paper.

  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.

FIG. 2 shows a cross-sectional view of the front plate 1 before becoming a display. In addition, in this figure, since it is still before bonding, the unnecessary peeling material layer 16 and the peeling film 17 are extra in the state of a display. In the post-process, the release material layer 16 and the release film 17 are removed and bonded to the back plate by the adhesive material layer 15. In the present invention, a conductive film is used for the release film 17. Examples of the conductive film 17 include an ITO vapor-deposited film based on polyethylene terephthalate and an aluminum vapor-deposited film, and an aluminum vapor-deposited film is preferable in terms of cost. Laminate in such a direction that the aluminum deposition surface is on the inside. Moreover, as the thickness, 50-300 micrometers is preferable. In FIG. 2, the aluminum layer is indicated by 17a and the base material polyethylene terephthalate is indicated by 17b.

  Silicone or the like can be used as the release material layer 16.

  Here, as shown in FIG. 2, there is a portion of the front plate 1 where the transparent electrode 13 and the conductive portion 17a of the conductive film are exposed to the outside, and a probe contacts the electrode portion to supply drive voltage. By supplying a voltage from the apparatus, the particles in the microcapsules of the electronic ink 14 can be electrophoresed, and the front plate can be brought into a white display state or a black display state.

  Hereinafter, means for accurately measuring the size and contrast of defects detected by visual inspection by an inspector or automatic inspection by an automatic inspection apparatus by driving the front plate of the display in this way will be described.

  FIG. 1 shows a schematic configuration of a method for using the measuring apparatus of the present invention. Since the front plate 1 has a portion where the conductive portion of the transparent electrode and the release film is taken out to the outside, the driving waveform generated by the signal generation unit 4 of the control unit 2 of the measuring device is brought into contact with the probe 6 of the measuring device. When applied, it acts as a drive voltage pulse applying means. Depending on the waveform, the particles in the microcapsules of the front plate 1 move to the front and back surfaces, and the entire surface of the front plate 1 changes to white or black. The image processing unit 3 picks up the entire surface of the front plate 1 with an imaging means with an image accuracy of about 2 to 3 μm / pixel with the area camera 5 in synchronization with the drive waveform generated by the drive waveform generation unit 4. The image is taken in as digital data, and the defect is measured as a measuring means.

  Here, the drive waveform and the imaging timing will be described with reference to FIG. The driving waveform is shown on the upper side, and the timing of the trigger signal input to the area camera is shown on the lower side. The area camera uses a type that can capture an image at the moment when a trigger signal is input. A positive voltage pulse 25 is applied to make the front plate 1 white, and a trigger signal is output to the camera in synchronization with the end of the pulse, and imaging is performed at the imaging timing 28. Similarly, the black state after application of the negative voltage pulse 26 is imaged at the imaging timing 29. The same applies to gray. The signal generation unit 4 realizes this by preparing waveform pattern data of two channels in advance using a D / A conversion board or the like, and starting output of the two channels simultaneously.

  Images captured by the area camera are digitized and stored in a computer memory. The image data is binarized into a defective portion and a non-defective portion by image processing. A method such as a discriminant analysis method can be used to determine the threshold value for binarization. After binarization, the pixels are added in the horizontal and vertical directions, the boundary position between the defective portion and the non-defective portion is calculated, and the width and height of the circumscribed rectangle of the defective portion are used as the defect size.

  Then, the average gradation value of the binarized defect area and the average gradation value of the non-defect area are calculated. For this, conversion is made to the reflectance using a conversion table from gradation values to reflectance that has been created in advance. The table is created by capturing a calibration plate such as a gray scale chart measured for reflectance using a spectrophotometer and the like, and approximating with a multi-order curve from the relationship with the gradation value, and complementing the values. And the value which divided the larger one of the reflectance of a defective part and a non-defect part by the smaller one is made into contrast.

The present invention is a technique related to an apparatus for measuring the defect size and contrast of a front plate, which is one of components of an electronic paper display.

It is an apparatus schematic diagram showing an example of the present invention. It is a figure which shows the layer structure of the front board before adhesion | attachment. It is a schematic sectional drawing of the display of this invention. It is a schematic sectional drawing of the microcapsule used for the front board of this invention. It is a related explanation perspective view of the drive state and display of the microcapsule of the present invention. FIG. 6 is an explanatory perspective view of a driving state when a microcapsule different from the microcapsule of FIG. 5 of the present invention is used. It is explanatory drawing sectional drawing of the color display by the drive state of the microcapsule of this invention. It is a timing chart of a drive signal and an imaging trigger signal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front plate 2 Control part 3 Image processing unit 4 Signal generation unit 5 Area camera 6 Probe 7 Video signal 8 Trigger signal 12 Base material transparent film 13 Transparent electrode 14 Electronic ink 15 Adhesive layer 16 Release material layer 17a Release film (conductivity layer)
17b Release film (base film)
25 Positive voltage pulse 26 Negative voltage pulse 27 Positive voltage pulse 28 White image capturing timing 29 Black image capturing timing 30 Gray image capturing timing 41 Display 41b Electrode film 41d Electrode film 41e Base material 41f Color filter 42 Image display layer 43 Base material 44 Common Electrode 45 External electrode 110 Microcapsule 111 Capsule shell 113 White particles 114 Black particles 115 Dispersion medium

Claims (1)

In the front plate of a display formed by peeling off a release film of a front plate comprising at least a substrate, an electrode, a display material, an adhesive layer and a release film, and bonding a back plate comprising at least a substrate, an electrode or a drive element, the front plate A conductive film is used as the release film, and a driving voltage pulse for driving the display material is applied between the electrode and the conductive film, so that the presence or absence of display defects can be inspected before being bonded to the back plate. In the front panel defect measuring device for the front panel of the display,
A driving voltage pulse applying means for applying a driving voltage pulse in which the contrast of the defective part is maximized;
Imaging means for imaging with a camera in synchronization with the end of application of the drive voltage pulse;
A measuring unit that performs image processing on the image captured by the imaging unit to measure the size and contrast of the defective portion;
A front plate defect measuring device comprising:

Images