JP4701869B2 - Liquid crystal device - Google Patents

Description

  The present invention relates to a liquid crystal device having an element substrate on which an alignment film for aligning liquid crystals is formed and a substrate facing the element substrate, and a method for manufacturing the liquid crystal device.

  As is well known, a liquid crystal device is configured by sealing liquid crystal between two substrates such as a glass substrate and a quartz substrate. In an active matrix liquid crystal device, active elements such as thin film transistors (hereinafter referred to as TFTs) are arranged in a matrix on one substrate, and a counter electrode (transparent electrode (ITO (Indium Indium)) is disposed on the other substrate. By displaying Tin Oxide))) and changing the optical characteristics of the liquid crystal layer enclosed between the two substrates according to the image signal, image display is possible. The optical characteristics of the liquid crystal layer are controlled by applying a voltage based on an image signal to the liquid crystal layer and changing the alignment of the liquid crystal molecules.

  In order to define the alignment of liquid crystal molecules when no voltage is applied, an alignment film is formed on the surface of one substrate (element substrate) and the other substrate (counter substrate) in contact with the liquid crystal layer, and the alignment film is rubbed. Apply. The alignment films are formed by forming organic films such as soluble polyimide composed of acid anhydride and diamine, for example, on both substrates with a thickness of about several tens of nanometers. Orientation treatment can be performed along the plane. Further, by rubbing the surface of each alignment film, each alignment film is made an alignment anisotropy film to define the alignment of liquid crystal molecules.

  Then, by turning on the TFT element, an image signal is supplied to pixel electrodes (ITO) arranged in a matrix on the element substrate, and a voltage based on the image signal is applied to the liquid crystal layer between the pixel electrode and the counter electrode. Then, the arrangement of the liquid crystal molecules is changed. Thereby, the transmittance of the pixel is changed, and light passing through the pixel electrode and the liquid crystal layer is changed according to the image signal to perform image display.

  The TFT element is ON / OFF controlled by a scanning signal (gate signal) supplied via a scanning line (gate line). In a state where the scanning signal is applied and the TFT element is turned on, an image signal having a voltage corresponding to the gradation is applied to the pixel electrode via the data line (source line). Even if the TFT element is turned off after the voltage is supplied to the pixel electrode, the applied voltage of each pixel is maintained by the capacity of the liquid crystal layer, the storage capacity, and the like.

  By the way, in the liquid crystal device, due to the application of the DC component of the applied signal, for example, decomposition of the liquid crystal component, contamination due to impurities in the liquid crystal cell occurs, and a phenomenon such as burn-in of the display image appears. Therefore, in general, inversion driving is performed to invert the polarity of the driving voltage of each pixel electrode for each field in the image signal, for example.

  In the liquid crystal device, as described above, the driving voltage is applied to the pixel electrode only for a certain period in consideration of the capacitance. However, during a period in which the drive voltage is not applied to the pixel electrode, the voltage held in the pixel gradually decreases due to the influence of coupling capacitance and charge leakage.

  In this case, the decrease in the voltage applied to the electrode during positive polarity driving is greater than the decrease in the voltage applied to the electrode during negative polarity driving. Therefore, each alignment film formed on the element substrate and the counter substrate is negative or positive. It becomes easy to accumulate the electric charge.

  Therefore, when charges are accumulated in the alignment films formed on the element substrate and the counter substrate, the above-described impurity ions (hereinafter referred to as impurity ions) are generated between the alignment films of the element substrate or the counter substrate and the liquid crystal. It tends to remain at the interface.

  As a result, impurity ions are adsorbed on each alignment film of the element substrate and the counter substrate, but when the amount of adsorption of the impurity ions is extremely biased between the alignment film of the element substrate and the alignment film of the counter substrate, The influence of the direct current component applied to the liquid crystal due to excessively adsorbed ions on the alignment film is increased, which accelerates the burn-in phenomenon of the display image.

  In view of such a problem, for example, in Patent Document 1, the amount of charge accumulation in the alignment film of the element substrate and the counter substrate is increased by changing the film thickness between the alignment film on the element substrate side and the alignment film on the counter substrate side. There has been proposed a technique for reducing the burn-in phenomenon of a display image.

In Patent Document 2, the rubbing strength applied to the alignment film on the element substrate side and the alignment film on the counter substrate side is made different between the alignment film on the element substrate side and the alignment film on the counter substrate side. Techniques for preventing the burn-in phenomenon have been proposed.
JP-A-8-146422 JP 2004-287064 A

  However, in the technique disclosed in Patent Document 1, the amount of charge accumulated in each alignment film of the element substrate and the counter substrate is reduced, but it is not completely eliminated, so that the display image burn-in phenomenon is completely prevented. I'm not sure if I can do it.

  In the technique disclosed in Patent Document 2, when the rubbing strength applied to the alignment film on the element substrate side and the alignment film on the counter substrate side is made different, the accuracy of the rubbing strength is increased to the alignment film on the element substrate side and the counter substrate. Since each of the alignment films on the side must be secured, the accuracy control of the rubbing strength becomes complicated.

  The object of the present invention has been made by paying attention to the above circumstances, and can easily prevent burn-in of a display image by adjusting the polarization of charges accumulated in the alignment film of the element substrate and the alignment film of the counter substrate. It is in providing the manufacturing method of a liquid crystal device and a liquid crystal device which have the structure which carries out.

In order to achieve the above object, a liquid crystal device according to the present invention includes an element substrate and a counter substrate opposed to the element substrate arranged to face each other via a sealing material, and a liquid crystal between the element substrate and the counter substrate. A first alignment film for aligning the liquid crystal formed on a side facing the liquid crystal of the element substrate, and a side facing the liquid crystal of the counter substrate, A second alignment film that aligns the liquid crystal, and the first alignment film includes an adhesion assistant that improves adhesion between the element substrate and the first alignment film, and the first alignment film. Any one of a cross-linking additive and a conductive material for bonding between soluble polyimide polymers constituting the substrate is added, and the second alignment film includes the counter substrate and the second alignment film. Adhesion assistant for improving adhesion with the second orientation An additive comprising a cross-linking additive for bonding between soluble polyimide polymers constituting the composition, an adhesion assistant for enhancing adhesion between the counter substrate and the second alignment film, an additive composed of a conductive material, and the counter substrate Addition of any one of an adhesion assistant for enhancing adhesion to the second alignment film, a crosslinking additive for bonding between the soluble polyimide polymers constituting the second alignment film, and an additive made of a conductive material An agent is added .
Further, in a liquid crystal device in which an element substrate and a counter substrate facing the element substrate are arranged to face each other via a sealing material, and liquid crystal is interposed between the element substrate and the counter substrate, the element substrate A first alignment film for aligning the liquid crystal formed on the side facing the liquid crystal; and a second alignment film for aligning the liquid crystal formed on the side facing the liquid crystal of the counter substrate. In addition, the first alignment film has a cross-linking additive that bonds between an adhesion assistant that enhances adhesion between the element substrate and the first alignment film and a soluble polyimide polymer that constitutes the first alignment film. Any one of an additive composed of an additive, an adhesion assistant that enhances adhesion between the element substrate and the first alignment film, and an additive composed of a conductive material is added, and the second The alignment film includes the counter substrate and the second substrate. Adhesion aid to improve the adhesion between the alignment film, wherein the second crosslinking additive coupling between polymers soluble polyimide that constitutes the alignment layer and additives made of conductive material is added.
Further, in a liquid crystal device in which an element substrate and a counter substrate facing the element substrate are arranged to face each other via a sealing material, and liquid crystal is interposed between the element substrate and the counter substrate, the element substrate A first alignment film for aligning the liquid crystal formed on the side facing the liquid crystal; and a second alignment film for aligning the liquid crystal formed on the side facing the liquid crystal of the counter substrate. In addition, the first alignment film has a cross-linking additive that bonds between an adhesion assistant that enhances adhesion between the element substrate and the first alignment film and a soluble polyimide polymer that constitutes the first alignment film. An additive comprising an agent, an adhesion assistant for enhancing adhesion between the counter substrate and the first alignment film, an additive comprising an electrically conductive material, and adhesion for enhancing adhesion between the element substrate and the first alignment film Auxiliary agent, soluble constituting the second alignment film Any one of a cross-linking additive that bonds between polyimide polymers and an additive made of a conductive material is added, and the second alignment film includes the counter substrate and the second alignment film. It is characterized by the addition of any one of an adhesion assistant for enhancing adhesion with the cross-linking additive for bonding between the polymers of the soluble polyimide constituting the second alignment film, and a conductive material. To do.
Further, in a liquid crystal device in which an element substrate and a counter substrate facing the element substrate are arranged to face each other via a sealing material, and liquid crystal is interposed between the element substrate and the counter substrate, the element substrate A first alignment film for aligning the liquid crystal formed on the side facing the liquid crystal; and a second alignment film for aligning the liquid crystal formed on the side facing the liquid crystal of the counter substrate. In addition, the first alignment film includes an adhesion assistant that enhances adhesion between the element substrate and the first alignment film, and a cross-linking additive that bonds between the polymers of the soluble polyimide constituting the first alignment film. An additive made of an agent and a conductive material is added, and the second alignment film is provided with an adhesion assistant for enhancing adhesion between the counter substrate and the second alignment film, and the second alignment film. Crosslinking for bonding between constituent soluble polyimide polymers. Any one of an additive composed of an additive, an adhesion assistant that enhances adhesion between the counter substrate and the second alignment film, and an additive composed of a conductive material is added. .

  According to the liquid crystal device of the present invention, the polarization characteristics of the first alignment film and the second alignment film in the first alignment film formed on the element substrate and the second alignment film formed on the counter substrate. Specifically, the additive concentration of the additive of the same material that makes the difference is set to a different value, specifically, the additive concentration of the additive in the alignment film with a small amount of charge accumulation is set to a high value. Therefore, the first alignment film and the second alignment film have different film qualities, and the amount of charge accumulated excessively in one of the first alignment film and the second alignment film is different from the first alignment film. The alignment film and the second alignment film are adjusted to be equal. That is, the polarization is adjusted between the first alignment film and the second alignment film. From this, the adsorption amount of impurity ions can be made uniform between the first alignment film and the second alignment film, and the burn-in of the display image can be easily prevented.

  The second alignment film is characterized in that the additive concentration of the additive is set higher than that of the first alignment film.

  According to the liquid crystal device of the present invention, due to the element structure of the element substrate, even if the charge accumulation amount is biased in the first alignment film and excessive impurity ions are attached, the second alignment film is By setting the additive concentration of the additive of the same material to a value higher than that of the alignment film, charges are likely to be accumulated in the second alignment film, impurity ions are easily adsorbed, and the impurity ions are While being diffused into the liquid crystal from the first alignment film, it is easily relaxed between the electrodes of the element substrate. Therefore, the amount of charge accumulated excessively in the second alignment film is adjusted to be equal between the first alignment film and the second alignment film. That is, the polarization is adjusted between the first alignment film and the second alignment film. From this, it is possible to make the adsorption amount of impurity ions uniform between the first alignment film and the second alignment film, and thus it is possible to easily prevent burn-in of the display image.

  Further, the additive includes an adhesion assistant that improves adhesion between the element substrate and the first alignment film and adhesion between the counter substrate and the second alignment film, the first alignment film, It is at least one of a cross-linking additive for bonding between soluble polyimide polymers constituting the second alignment film, and a conductive material.

  According to the liquid crystal device of the present invention, the adhesion assistant improves the adhesion between the element substrate and the first alignment film and the adhesion between the counter substrate and the second alignment film. Promotes ion adsorption. Moreover, since the crosslinking additive can bond between the polymers of the soluble polyimide constituting the first alignment film and the second alignment film, the addition of the crosslinking additive promotes the adsorption of impurity ions in the alignment film. Furthermore, the conductive particles increase the charge accumulated in the alignment film when added, and thus promote the adsorption of impurity ions in the alignment film. Therefore, the addition concentration of the additive of at least one same material of the adhesion assistant, the crosslinking additive, and the conductive particles is set to a different value between the first alignment film and the second alignment film, Specifically, the addition concentration of the additive of at least one same material of the adhesion assistant, the crosslinking additive, and the conductive particles of the alignment film with a small amount of accumulated charge is set to a high value. The first alignment film and the second alignment film have different film qualities, and the amount of charge accumulated excessively in one of the first alignment film and the second alignment film is different from that of the first alignment film. It is adjusted so as to be uniform with the second alignment film. That is, the polarization is adjusted between the first alignment film and the second alignment film. From this, the adsorption amount of impurity ions can be made uniform between the first alignment film and the second alignment film, and the burn-in of the display image can be easily prevented.

  Further, in the first alignment film and the second alignment film, at least one addition concentration of the adhesion assistant, the crosslinking additive, and the conductive material is set to a different value. To do.

  According to the liquid crystal device of the present invention, at least one addition concentration of the adhesion assistant, the crosslinking additive, and the conductive material is set to a different value in the first alignment film and the second alignment film. Specifically, the alignment film having a small amount of accumulated charge has a high concentration of at least one of the adhesion assistant, the crosslinking additive, and the conductive particles, so that the first alignment film The film quality is different from that of the second alignment film, and the amount of charge accumulated excessively in one of the first alignment film and the second alignment film is different from that of the first alignment film and the second alignment film. And are adjusted to be equal. That is, the polarization is adjusted between the first alignment film and the second alignment film. From this, the adsorption amount of impurity ions can be made uniform between the first alignment film and the second alignment film, and the burn-in of the display image can be easily prevented.

  Further, the first alignment film and the second alignment film are different in the number of components of the additive by at least one of the adhesion assistant, the crosslinking additive, and the conductive material. And

  According to the liquid crystal device of the present invention, the first alignment film and the second alignment film differ in the number of constituents of the additive composed of at least one of an adhesion assistant, a crosslinking additive, and a conductive material. More specifically, the orientation of the alignment film with a small amount of charge accumulation has increased the composition of the additive consisting of at least one of an adhesion assistant, a crosslinking additive, and conductive particles. The film quality is different between the first alignment film and the second alignment film, and the amount of charge accumulated excessively in one of the first alignment film and the second alignment film is different from that of the first alignment film and the second alignment film. It is adjusted to be uniform with the alignment film. That is, the polarization is adjusted between the first alignment film and the second alignment film. From this, the adsorption amount of impurity ions can be made uniform between the first alignment film and the second alignment film, and the burn-in of the display image can be easily prevented.

  The liquid crystal device according to the present invention is a liquid crystal device in which an element substrate and a counter substrate facing the element substrate are arranged to face each other via a sealing material, and liquid crystal is interposed between the element substrate and the counter substrate. A first alignment film for aligning the liquid crystal formed on the element substrate facing the liquid crystal, and a second alignment film for aligning the liquid crystal formed on the counter substrate facing the liquid crystal. And the additive that makes the polarization characteristics of the first alignment film and the second alignment film different is any of the first alignment film and the second alignment film. It is characterized by being added to.

  According to the liquid crystal device of the present invention, any one of the first alignment film and the second alignment film in the first alignment film formed on the element substrate and the second alignment film formed on the counter substrate. In addition, by adding an additive that varies polarization characteristics, specifically, by adding an additive to an alignment film with a small amount of charge accumulation, the first alignment film and the second alignment film The film quality is different between the alignment films, and the amount of charge accumulated excessively in one of the first alignment film and the second alignment film is equal between the first alignment film and the second alignment film. It has been adjusted to be. That is, the polarization is adjusted between the first alignment film and the second alignment film. From this, the adsorption amount of impurity ions can be made uniform between the first alignment film and the second alignment film, and the burn-in of the display image can be easily prevented.

  The additive includes an adhesion assistant that improves adhesion between the element substrate and the first alignment film and adhesion between the counter substrate and the second alignment film, the first alignment film, and the first alignment film. It is at least one of a cross-linking additive for bonding between soluble polyimide polymers constituting the second alignment film, and a conductive material.

  According to the liquid crystal device of the present invention, the presence or absence of the additive consisting of at least one of the adhesion assistant, the crosslinking additive, and the conductive particles differs between the first alignment film and the second alignment film. Specifically, the first alignment film and the first alignment film can be obtained by adding an additive composed of at least one of an adhesion assistant, a crosslinking additive, and conductive particles to the alignment film having a small amount of accumulated charge. The film quality is different between the first alignment film and the second alignment film, and the amount of charge accumulated excessively in one of the first alignment film and the second alignment film is different between the first alignment film and the second alignment film. It has been adjusted to be even. That is, the polarization is adjusted between the first alignment film and the second alignment film. From this, the adsorption amount of impurity ions can be made uniform between the first alignment film and the second alignment film, and the burn-in of the display image can be easily prevented.

In the method for manufacturing a liquid crystal device according to the reference invention of the present invention , an element substrate and a counter substrate facing the element substrate are arranged to face each other with a sealant interposed therebetween, and liquid crystal is interposed between the element substrate and the counter substrate. In the liquid crystal device manufacturing method, the first additive that makes the polarization characteristics of the first alignment film and the second alignment film different is added to the element substrate facing the liquid crystal. A step of forming a first alignment film for aligning the liquid crystal, and a second addition set to a concentration different from that of the first additive on the opposite substrate facing the liquid crystal And a step of forming a second alignment film to which the liquid crystal is aligned, to which an agent is added.

According to the method for manufacturing a liquid crystal device according to the reference invention of the present invention, in the step of forming the first alignment film on the element substrate and the second alignment film on the counter substrate, the addition of the same material that varies the polarization characteristics of the liquid crystal By setting the additive concentration of the agent to different values for the first alignment film and the second alignment film, specifically, the additive concentration of the alignment film with a small amount of charge accumulation is set to a high value. As a result, the first alignment film and the second alignment film have different film qualities, and the amount of charge accumulated excessively in one of the first alignment film and the second alignment film is the first alignment film. The alignment film and the second alignment film are adjusted to be equal. That is, the polarization is adjusted between the first alignment film and the second alignment film. From this, the adsorption amount of impurity ions can be made uniform between the first alignment film and the second alignment film, and the burn-in of the display image can be easily prevented.

In the method for manufacturing a liquid crystal device according to the reference invention of the present invention , an element substrate and a counter substrate facing the element substrate are arranged to face each other with a sealant interposed therebetween, and liquid crystal is interposed between the element substrate and the counter substrate. In the method for manufacturing a liquid crystal device, a step of forming a first alignment film for aligning the liquid crystal on a side of the element substrate facing the liquid crystal, and a side of the counter substrate facing the liquid crystal Forming a second alignment film for aligning liquid crystal, and an additive for differentiating the polarization characteristics of the first alignment film and the second alignment film includes: It is added to any one of the second alignment films.

According to the method for manufacturing a liquid crystal device according to the reference invention of the present application, in the step of forming the first alignment film on the element substrate and the second alignment film on the counter substrate, the additive that changes the polarization characteristics of the liquid crystal is added. By adding to one of the first alignment film and the second alignment film, specifically, by adding an additive to the alignment film having a small amount of charge accumulation, The film quality is different between the second alignment film and the amount of charge accumulated excessively in one of the first alignment film and the second alignment film is different between the first alignment film and the second alignment film. It is adjusted to be equal. That is, the polarization is adjusted between the first alignment film and the second alignment film. From this, the adsorption amount of impurity ions can be made uniform between the first alignment film and the second alignment film, and the burn-in of the display image can be easily prevented.

  Embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, the liquid crystal device will be described by taking, as an example, a liquid crystal device using an element substrate on which a switching element such as a TFT (thin film transistor) is formed and a counter substrate disposed opposite to the element substrate. .

(First embodiment)
FIG. 1 is a plan view of a liquid crystal device according to a first embodiment of the present invention as viewed from the counter substrate side together with the components formed thereon, and FIG. 2 is taken along the line II-II in FIG. FIG. 9 is a cross-sectional view, and FIG. 9 is a diagram showing an equivalent circuit of elements constituting the pixel on the element substrate of FIG.

  As shown in FIG. 1, a liquid crystal device 1 includes, for example, a quartz substrate, a glass substrate, an element substrate (hereinafter referred to as a TFT substrate) 10 using a silicon substrate, and a TFT substrate 10 disposed so as to face the substrate, for example, glass. A liquid crystal 50 is sealed in an internal space between the substrate and a counter substrate 20 using a quartz substrate. The TFT substrate 10 and the counter substrate 20 that are arranged to face each other are bonded together by a sealing material 52.

  Pixel electrodes (ITO) 9 (see FIG. 2) constituting pixels are arranged in a matrix on a surface 10a on the side of the TFT substrate 10 that is in contact with the liquid crystal 50, and the display region of the liquid crystal device 1 is disposed on the surface 10a. A display area 10h of the TFT substrate 10 constituting 40 is configured.

  Specifically, as shown in FIG. 9, in the display area 10h, the plurality of scanning lines 3a and the plurality of data lines 6a are wired so as to intersect with each other, and are divided by the scanning lines 3a and the data lines 6a. A plurality of pixel electrodes 9 are arranged in a matrix in the region. A TFT element 30 is provided corresponding to each intersection of the scanning line 3a and the data line 6a.

  The TFT element 30 includes a source electrode (not shown) electrically connected to the data line 6a, a semiconductor layer, and a drain electrode (not shown) electrically connected to the pixel electrode 9. The TFT element 30 is turned on by the ON signal of the scanning line 3 a, whereby the image signal supplied to the data line 6 a is supplied to the pixel electrode 9. At this time, in order to prevent burn-in of the display image and the like, inversion driving is performed to invert the polarity of the driving voltage applied to each pixel electrode 9 for each field in the image signal, for example. A voltage between the pixel electrode 9 and a later-described counter electrode 21 provided on the counter substrate 20 is applied to the liquid crystal 50.

  In addition, a storage capacitor 70 is provided in parallel with the pixel electrode 9, and the storage capacitor 70 can hold the voltage of the pixel electrode 9 for a time that is, for example, three orders of magnitude longer than the time when the source voltage is applied. . The storage capacitor 70 improves the voltage holding characteristic and enables image display with a high contrast ratio.

  Further, a common electrode (ITO) 21 is provided on the entire surface 20a of the counter substrate 20 that is in contact with the liquid crystal 50, and the surface 20a of the common electrode 21 at a position facing the display region 10h of the TFT substrate 10 is provided. In addition, a display area 20 h of the counter substrate 20 constituting the display area 40 of the liquid crystal device 1 is configured.

  A rubbing-processed first alignment film 16 is provided on the pixel electrode 9 of the TFT substrate 10, and the rubbing process is also performed on the common electrode 21 formed over the entire surface of the counter substrate 20. A processed second alignment film 26 is provided. The detailed configuration of the first alignment film 16 and the second alignment film 26 will be described later.

  The counter substrate 20 is provided with a light shielding film 53 as a frame that defines and defines the outer periphery of the display area 10 h of the TFT substrate 10 and the display area 20 h of the counter substrate 20.

  The sealing material 52 includes a circumferential sealing material forming region 10 s (see FIG. 3) provided on the surface 10 a of the TFT substrate 10 and a circumferential sealing material forming region 20 s that substantially matches the contour shape of the surface 20 a of the counter substrate 20. (Refer to FIG. 4), the TFT substrate 10 and the counter substrate 20 are fixed to each other.

  The sealing material 52 is missing at a part of one side of the TFT substrate 10, and the liquid crystal 50 is injected between the TFT substrate 10 and the counter substrate 20 bonded from the missing part by a known cell injection method. A liquid crystal inlet 108 is formed for this purpose. The liquid crystal injection port 108 is sealed with a sealing material 109 after the liquid crystal is injected. When the liquid crystal 50 is sealed between the TFT substrate 10 and the counter substrate 20 by a known liquid crystal dropping method, the liquid crystal injection port 108 need not be formed on the sealing material 52.

  An external connection for connecting the data line driving circuit 101 for driving the data line by supplying an image signal to a data line (not shown) of the TFT substrate 10 at a predetermined timing in a region outside the sealing material 52. A terminal 102 is provided along one side of the TFT substrate 10.

  Scan line drive circuits 103 and 104 for driving the gate electrodes are provided along two sides adjacent to the one side by supplying scanning signals to scanning lines and gate electrodes (not shown) of the TFT substrate 10 at a predetermined timing. ing. The scanning line driving circuits 103 and 104 are formed on the TFT substrate 10 at a position facing the light shielding film 53 inside the sealing material 52.

  Further, on the TFT substrate 10, wiring 105 connecting the data line driving circuit 101, the scanning line driving circuits 103 and 104, the external connection terminal 102, and the vertical conduction terminal 107 is provided to face the three sides of the light shielding film 53. ing.

  The vertical conduction terminals 107 are formed on the four TFT substrates 10 at the corners of the sealing material 52. Between the TFT substrate 10 and the counter substrate 20, a vertical conductive material 106 having a lower end in contact with the vertical conductive terminal 107 and an upper end in contact with the common electrode 21 is provided. And the counter substrate 20 are electrically connected.

  Here, the configuration of the surface 10a of the TFT substrate 10 on which the first alignment film 16 is formed and the surface 20a of the counter substrate 20 on which the second alignment film 26 is formed will be described. 3 is a schematic plan view of the TFT substrate of FIG. 1 having a first alignment film formed on the surface, and FIG. 4 is a schematic plan view of the counter substrate of FIG. 1 having a second alignment film formed on the surface. is there.

  As shown in FIG. 3, the first alignment film 16 is formed on the surface 10a of the TFT substrate 10 and in the display area 10h formed inside the circumferential seal material forming area 10s. The first alignment film 16 is made of, for example, a first additive that changes the polarization characteristics of the first alignment film 16 and the second alignment film 26 to a soluble polyimide composed of acid anhydride and diamine. Consists of added in concentration.

  The first additive includes an adhesion assistant that improves the adhesion between the TFT substrate 10 and the first alignment film 16, specifically, the adhesion between the pixel electrode 9 and the first alignment film 16, and a soluble polyimide. It comprises at least one of a cross-linking additive for bonding between the polymers and a conductive material.

  Therefore, the first additive may be composed of each of the adhesion assistant, the crosslinking additive, and the conductive material, or the adhesion assistant + crosslinking additive, the adhesion assistant + conductive material, The cross-linking additive + conductive material and the adhesion assistant + cross-linking additive + conductive material may be used.

  The adhesion assistant enhances the adhesion between the pixel electrode 9 of the TFT substrate 10 and the first alignment film 16 and the adhesion between the common electrode 21 of the counter substrate 20 and the second alignment film 26. The resistance at the interface 34 (see FIG. 2) between the electrode 9 and the first alignment film 16 and the resistance at the interface 44 (see FIG. 2) between the common electrode 21 and the second alignment film 26 are increased. Adsorption of the alignment films 16 and 26 of impurity ions, which will be described later, remaining on the interfaces 33 and 34 (see FIG. 2) with the alignment films 16 and 26 is promoted. That is, the surface energy of the interfaces 33 and 34 of the alignment films 16 and 26 is increased by the addition.

  Moreover, since the crosslinking additive can bond between the polymers of the soluble polyimide constituting the first alignment film 16 and the second alignment film 26, the addition increases the resistance of the interface 34 and the resistance of the interface 44. Adsorption of the alignment films 16 and 26 of impurity ions, which will be described later, remaining on the interfaces 33 and 34 (see FIG. 2) is promoted. That is, the surface energy of the interfaces 33 and 34 of the alignment films 16 and 26 is increased by the addition.

  Furthermore, since the amount of charge accumulated in the alignment films 16 and 26 increases due to the addition of the conductive particles, adsorption of the alignment films 16 and 26 of impurity ions, which will be described later, remaining on the interfaces 33 and 34 (see FIG. 2). Facilitate. That is, the surface energy of the interfaces 33 and 34 of the alignment films 16 and 26 is increased by the addition.

  As shown in FIG. 4, the second alignment film 26 is formed on the entire surface 20 a of the counter substrate 20. Note that the second alignment film 26 may be formed only at least in the display region 20 h of the surface 20 a of the counter substrate 20.

  The second alignment film 26 is made of the same soluble polyimide as the first alignment film 16 made of, for example, acid anhydride and diamine, and the polarization characteristics of the first alignment film 16 and the second alignment film 26 are different. The second additive having the same material structure as the first additive to be added is added. Note that the second additive is set to a value of an additive concentration different from that of the first additive.

  The second additive includes an adhesion assistant that improves the adhesion between the counter substrate 20 and the second alignment film 26, specifically, the adhesion between the common electrode 21 and the second alignment film 26, and a soluble polyimide. At least one of a cross-linking additive for bonding between the polymers and the conductive material.

  Therefore, the second additive may also be composed of each of the adhesion assistant, the crosslinking additive, and the conductive material. The adhesion assistant + crosslinking additive, the adhesion assistant + conductive material, The cross-linking additive + conductive material and the adhesion assistant + cross-linking additive + conductive material may be used, but the first additive has the same material.

  From this, the second additive is set to a value at which at least one addition concentration of the adhesion aid to the soluble polyimide, the crosslinking additive, and the conductive material is different from that of the first additive. .

  Next, a manufacturing method of the liquid crystal device 1 configured as described above will be described with reference to FIG. FIG. 5 is a flowchart showing a method for manufacturing the liquid crystal device according to the present embodiment. In addition, since manufacturing processes other than the process of forming the first alignment film 16 and the second alignment film 26 are the same as those in the related art, description thereof is omitted.

  As shown in the figure, first, in step S1, the TFT substrate 10 on which the pixel electrodes 9 and the like are formed is set in an alignment film forming apparatus. Next, in step S2, the first alignment film 16 in which the first additive is added to the soluble polyimide at a specific concentration on the surface 10a of the TFT substrate 10 in the display region 10h is, for example, printed or inkjet. It is formed with a thickness of about several tens of nanometers by a droplet discharge means having an equivalent configuration. Thereafter, the process proceeds to step S3.

  In step S3, the counter substrate 20 on which the common electrode 21 and the like are formed is set in the alignment film forming apparatus. Next, in step S4, the second alignment film 26 in which the second additive is added to the soluble polyimide is applied to the entire surface including at least the display region 20h on the surface 20a of the counter substrate 20, for example, by printing or inkjet. The first alignment film 16 is formed to have the same thickness by a droplet discharge means having the same configuration as that of the first alignment film 16. The second additive is the same material as the first additive, and the additive concentration is set to a different value.

  Finally, the alignment films 16 and 26 formed on the TFT substrate 10 and the counter substrate 20 are subjected to a rubbing process for aligning the molecules of the liquid crystal 50 along the surfaces of the TFT substrate 10 and the counter substrate 20. Ends. In this way, the alignment films 16 and 26 are formed on the surface 10 a of the TFT substrate 10 used in the liquid crystal device 1 and the surface 20 a of the counter substrate 20.

  As described above, in the liquid crystal device 1 according to the present embodiment, charges are accumulated in the first alignment film 16 and the second alignment film 26, and the interface 33 between the first alignment film 16 and the liquid crystal 50 (see FIG. 2), and even if the amount of impurity ions in the liquid crystal 50 adsorbed on the interface 43 (see FIG. 2) between the second alignment film 26 and the liquid crystal 50 is extremely biased, the adhesion assistant and the crosslinking additive are added. The addition concentration of at least one additive of the agent and the conductive particles is set to a different value between the first alignment film 16 and the second alignment film 26. Specifically, the addition concentration of at least one of the adhesion assistant, the crosslinking additive, and the conductive particles of the alignment film with a small amount of accumulated charge is set to a high value.

  As a result, the first alignment film and the second alignment film have different film qualities, and the amount of charge accumulated excessively in one of the first alignment film and the second alignment film is added. The surface energy at the interface of the alignment film with less charge accumulation is increased by the concentration of the agent, so that the first alignment film and the second alignment film are adjusted to be uniform.

  That is, the charge polarization is adjusted between the first alignment film 16 and the second alignment film. Therefore, the first alignment film 16 and the second alignment film 26 can equalize the amount of adsorbed impurity ions, and the display image can be easily prevented from being burned.

  It should be noted that which of the first and second alignment films 16 and 26 has a greater or lesser amount of charge accumulation can be obtained from experimental values. Therefore, when the first alignment film 16 and the second alignment film 26 are formed using the experimental values, the additive concentration of any one of the first alignment film 16 and the second alignment film 26 is added. Is set to a high value, the configuration of the liquid crystal device 1 of the present embodiment can be realized.

  Hereinafter, modifications will be described.

  In this embodiment, the additive concentration of the first additive added to the first alignment film and the additive concentration of the second additive added to the second alignment film are set to different values. It showed. Specifically, it was shown that the set value of at least one addition concentration of the adhesion assistant, the crosslinking additive, and the conductive material is different between the first additive and the second additive.

  At this time, if the addition concentration of the second additive is set to a value higher than the addition concentration of the first additive, the burn-in of the display image can be more effectively prevented.

  Specifically, due to the element structure of the TFT substrate 10, even if the charge accumulation amount is biased in the first alignment film 16 and excessive impurity ions are attached, the second alignment film 26 is By setting the additive concentration higher than that of the alignment film 16, charges are easily accumulated in the second alignment film 26 and the surface energy of the interface 43 of the second alignment film 26 is increased. As a result, impurity ions are easily adsorbed to the second alignment film 26, and the impurity ions are diffused from the first alignment film 16 into the liquid crystal 50 and are relaxed between the pixel electrodes 9 of the TFT substrate 10. It becomes easy.

  Therefore, the amount of charge accumulated excessively in the second alignment film 26 is adjusted to be equal between the first alignment film 16 and the second alignment film 26. That is, since the polarization of charges is adjusted by the first alignment film 16 and the second alignment film 26 and the amount of adsorbed impurity ions can be made uniform, burn-in of the display image can be easily prevented. .

  Further, another modification example will be described below. FIG. 6 is a chart showing a modified example in which the composition of the additive is different between the first alignment film and the second alignment film.

  In the present embodiment, the first alignment film 16 and the second alignment film 26 have the same configuration of the additive that is a material added to the soluble polyimide constituting each alignment film 16, 26. However, the configuration of the additive is not limited to this, and the first alignment film 16 and the second alignment film 26 may be different.

  Specifically, in the first alignment film 16 and the second alignment film 26, the number of constituents of the additive by at least one of the adhesion assistant, the crosslinking additive, and the conductive material is different. In this case, it is sufficient that the composition of the additive by at least one of the adhesion assistant, the crosslinking additive, and the conductive particles of the alignment film with a small amount of charge accumulation is sufficient.

  According to this, the first alignment film 16 and the second alignment film 26 have different film qualities, and the surface energy at the interface of the alignment film with less charge accumulation is increased by the additive. The amount of charge accumulated excessively in one of the first alignment film 16 and the second alignment film 26 is adjusted to be equal between the first alignment film 16 and the second alignment film 26.

  That is, since the charge polarization is adjusted by the first alignment film 16 and the second alignment film 26, the amount of impurity ions adsorbed by the first alignment film 16 and the second alignment film 26 is equalized. It is possible to easily prevent burn-in of the display image.

  On the other hand, when the charge amount accumulated in the first alignment film 16 is large, as shown in FIG. 6A, when the adhesion assistant is A, the crosslinking additive is B, and the conductive particles are C, the first When any one of A, B, and C is added to the alignment film 16, any one of A + B, A + C, and A + B + C may be added to the second alignment film 26. Further, when A + B or A + C is added to the first alignment film 16, A + B + C may be added to the second alignment film 26.

  On the other hand, when the amount of charge accumulated in the second alignment film 26 is large, as shown in FIG. 6B, when any of A, B, and C is added to the second alignment film 26, Any one of A + B, A + C, and A + B + C may be added to one alignment film 16. Further, when A + B or A + C is added to the second alignment film 26, A + B + C may be added to the first alignment film 16.

(Second Embodiment)
FIG. 7 is a cross-sectional view of a liquid crystal device showing a second embodiment of the present invention.

  The configuration of the liquid crystal device according to the second embodiment is different from that of the liquid crystal device 1 according to the first embodiment shown in FIGS. The only difference is that the additive is added. Therefore, only this difference will be described, and the same components as those of the liquid crystal device 1 of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 6, a first alignment film 216 that has been subjected to rubbing treatment is provided on the pixel electrode 9 of the TFT substrate 10 of the liquid crystal device 201, and the entire surface on the counter substrate 20 is provided. A second alignment film 226 that has been subjected to rubbing treatment is also provided on the formed common electrode 21. Even in this case, the second alignment film 226 may be formed only at least in the display region 20 h of the surface 20 a of the counter substrate 20.

  The first alignment film 216 and the second alignment film 226 are made of, for example, a soluble polyimide composed of an acid anhydride and a diamine, and one of the first alignment film 216 and the second alignment film 226. In this soluble polyimide, an additive that makes the polarization characteristics of the first alignment film 216 and the second alignment film 226 different is added at a specific concentration.

  The additive is at least one of the adhesion assistant described above, a crosslinking additive, and a conductive material. Therefore, the additive may be composed of a single component of the adhesion assistant, the crosslinking additive, and the conductive material. The adhesion assistant + crosslinking additive, the adhesion assistant + conductive material, and the crosslinking additive. You may be comprised from an agent + electrically-conductive material, adhesion assistant + bridge | crosslinking additive + electrically-conductive material.

  Next, a manufacturing method of the liquid crystal device 1 configured as described above will be described with reference to FIG. FIG. 8 is a flowchart showing a method for manufacturing the liquid crystal device of FIG. In this embodiment as well, the manufacturing steps other than the steps for forming the first alignment film 216 and the second alignment film 226 are the same as those in the prior art, and thus the description thereof is omitted.

  As shown in the figure, first, in step S11, the TFT substrate 10 on which the pixel electrodes 9 and the like are formed is set in an alignment film forming apparatus. Next, in step S12, whether or not an additive is added to the first alignment film 216 formed on the surface 10a of the TFT substrate 10 and in the display region 10h is selected. On the other hand, if an additive is added to the first alignment film, the process proceeds to step S13, where the additive is added to the soluble polyimide at a specific concentration on the surface 10a of the TFT substrate 10 and in the display region 10h. The first alignment film 216 is formed with a thickness of about several tens of nanometers by, for example, a droplet discharge unit having a configuration equivalent to that of printing or inkjet. Thereafter, the process proceeds to step S15.

  On the other hand, if no additive is added to the first alignment film 216 in step S12, the process branches to step S14, and the additive is formed on the surface 10a of the TFT substrate 10 and is made of soluble polyimide in the display region 10h. The first alignment film 216 to which no is added is formed with a thickness of about several tens of nanometers by, for example, a droplet discharge means having a configuration equivalent to that of printing or inkjet. Thereafter, the process proceeds to step S15.

  In step S15, the counter substrate 20 on which the common electrode 21 and the like are formed is set in the alignment film forming apparatus. Next, in step S <b> 16, whether or not an additive has been added to the first alignment film 216 is selected. On the other hand, if the additive is added to the first alignment film 216, the process proceeds to step S17, and the entire surface including the display region 20h on the surface 20a of the counter substrate 20 is made of soluble polyimide. The second alignment film 226 to which no additive is added is formed to the same thickness as the first alignment film 216 by, for example, a droplet discharge unit having a configuration equivalent to printing or inkjet.

  On the other hand, if the additive is not added to the first alignment film 216, the process branches to step S18, and the additive is added to the entire surface including the display region 20h on the surface 20a of the counter substrate 20 at a specific concentration. The second alignment film 226 added to the soluble polyimide is formed to the same thickness as the first alignment film 216 by, for example, a droplet discharge unit having a configuration equivalent to printing or inkjet.

  Finally, the alignment films 216 and 226 formed on the TFT substrate 10 and the counter substrate 20 are subjected to a rubbing process for aligning the molecules of the liquid crystal 50 along the surfaces of the TFT substrate 10 and the counter substrate 20. Ends. In this way, the alignment films 216 and 226 are formed on the surface 10 a of the TFT substrate 10 and the surface 20 a of the counter substrate 20 used in the liquid crystal device 201.

  As described above, in the liquid crystal device 201 of the present embodiment, charges are accumulated in the first alignment film 216 and the second alignment film 226, and the interface 233 between the first alignment film 216 and the liquid crystal 50 (see FIG. 7). Even if the amount of impurity ions in the liquid crystal 50 adsorbed on the interface 243 (see FIG. 7) between the second alignment film 226 and the liquid crystal 50 is extremely biased, the adhesion assistant, the crosslinking additive, and the conductivity By adding at least one additive to the particles to either the first alignment film 216 or the second alignment film 226, specifically, to the alignment film with a small amount of accumulated charge, By adding at least one additive of the adhesion assistant, the crosslinking additive, and the conductive particles, the first alignment film 216 and the second alignment film 226 have different film quality.

  Therefore, the amount of charge accumulated excessively in one of the first alignment film 216 and the second alignment film 226 increases the surface energy at the interface of the alignment film with less charge accumulation due to the presence or absence of the additive. Therefore, the first alignment film 216 and the second alignment film 226 are adjusted to be uniform.

  That is, the charge polarization is adjusted by the first alignment film 216 and the second alignment film 226. For this reason, the first alignment film 216 and the second alignment film 226 can equalize the amount of adsorption of impurity ions, and can easily prevent the display image from being burned.

  It should be noted that which of the first and second alignment films 216 and 226 has a greater or lesser charge accumulation can be determined by an experimental value. Therefore, when the first alignment film 216 and the second alignment film 226 are formed using the experimental values, an additive is added to either the first alignment film 216 or the second alignment film 226. Thus, the structure of the liquid crystal device 201 of this embodiment can be realized.

  Further, the liquid crystal device of the present invention is not limited to the illustrated examples described above, and it is needless to say that various changes can be made without departing from the scope of the present invention. For example, the above-described liquid crystal device has been described by taking an active matrix type liquid crystal display module using an active element (active element) such as a TFT (thin film transistor) as an example. The present invention can also be applied to an active matrix liquid crystal display module using active elements (active elements).

  The present invention is also applicable to display devices that form elements on a semiconductor substrate, such as LCOS (Liquid Crystal On Silicon).

  In LCOS, a single crystal silicon substrate is used as an element substrate, and a transistor is formed on a single crystal silicon substrate as a switching element used for a pixel or a peripheral circuit. In addition, a reflective pixel electrode is used for the pixel, and each element of the pixel is formed below the pixel electrode.

  The present invention also provides a display device in which a pair of electrodes are formed on the same layer of a substrate on one side, such as IPS (In-Plane Switching), or a pair of electrodes formed on an insulating substrate via an insulating film. It can also be applied to a display device FFS (Fringe Field Switching) or the like.

  Furthermore, as an electronic device in which the liquid crystal device according to the present invention is used, an optical projection display device such as a projector, a mobile phone, a portable information device called PDA (Personal Digital Assistants), a portable personal computer, a personal computer, Digital still camera, in-vehicle monitor, digital video camera, LCD TV, viewfinder type, monitor direct-view type video tape recorder, car navigation device, pager, electronic notebook, calculator, word processor, workstation, video phone, POS terminal, etc. And an apparatus using a liquid crystal display module which is an electro-optical device. Therefore, it goes without saying that the present invention can also be applied to these electronic devices.

The top view which looked at the liquid crystal device which shows 1st Embodiment of this invention from the opposing board | substrate side with each component formed on it. Sectional drawing which follows the II-II line | wire in FIG. FIG. 2 is a schematic plan view of the TFT substrate of FIG. 1 having a first alignment film formed on the surface. The schematic plan view of the opposing board | substrate of FIG. 1 with which the 2nd alignment film was formed in the surface. 6 is a flowchart showing a method for manufacturing a liquid crystal device according to the present embodiment. The chart which shows the modification from which the structure of an additive differs by the 1st alignment film and the 2nd alignment film. Sectional drawing of the liquid crystal device which shows 2nd Embodiment of this invention. 8 is a flowchart showing a method for manufacturing the liquid crystal device of FIG. The figure which shows the equivalent circuit of the element which comprises the pixel on the element substrate of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal device, 10 ... TFT substrate, 10a ... TFT substrate surface, 16 ... 1st alignment film, 20 ... Counter substrate, 20a ... Surface of counter substrate, 26 ... 2nd alignment film, 50 ... Liquid crystal, 52 ... Sealing material, 201... Liquid crystal device, 216... First alignment film, 226.

Claims (7)

In a liquid crystal device in which an element substrate and a counter substrate facing the element substrate are arranged to face each other via a sealing material, and liquid crystal is interposed between the element substrate and the counter substrate.
A first alignment film for aligning the liquid crystal, formed on a side of the element substrate facing the liquid crystal;
A second alignment film that is formed on the opposite substrate facing the liquid crystal and that aligns the liquid crystal;
The first alignment film includes an adhesion assistant that enhances adhesion between the element substrate and the first alignment film, a cross-linking additive that bonds between the polymers of the soluble polyimide constituting the first alignment film, and Any one of the conductive materials is added,
The second alignment film includes an adhesion assistant that enhances the adhesion between the counter substrate and the second alignment film, and a crosslinking additive that bonds between the soluble polyimide polymers constituting the second alignment film. Additive, an adhesion assistant that enhances adhesion between the counter substrate and the second alignment film, an additive made of a conductive material, and an adhesion assistant that increases adhesion between the counter substrate and the second alignment film The liquid crystal device is characterized in that any one of a cross-linking additive and an additive made of a conductive material for bonding between the soluble polyimide polymers constituting the second alignment film is added .   In a liquid crystal device in which an element substrate and a counter substrate facing the element substrate are arranged to face each other via a sealing material, and liquid crystal is interposed between the element substrate and the counter substrate.
A first alignment film for aligning the liquid crystal, formed on a side of the element substrate facing the liquid crystal;
A second alignment film that is formed on the opposite substrate facing the liquid crystal and that aligns the liquid crystal;
The first alignment film includes an adhesion assistant that enhances adhesion between the element substrate and the first alignment film, and a crosslinking additive that bonds between the polymers of the soluble polyimide constituting the first alignment film. Any one of the additive and the additive comprising the adhesion assistant and the conductive material that enhance the adhesion between the element substrate and the first alignment film is added,
  The second alignment film includes an adhesion assistant that enhances the adhesion between the counter substrate and the second alignment film, a crosslinking additive that bonds between the polymers of the soluble polyimide constituting the second alignment film, and A liquid crystal device, wherein an additive made of a conductive material is added.   In a liquid crystal device in which an element substrate and a counter substrate facing the element substrate are arranged to face each other via a sealing material, and liquid crystal is interposed between the element substrate and the counter substrate.
A first alignment film for aligning the liquid crystal, formed on a side of the element substrate facing the liquid crystal;
A second alignment film that is formed on the opposite substrate facing the liquid crystal and that aligns the liquid crystal;
The first alignment film includes an adhesion assistant that enhances adhesion between the element substrate and the first alignment film, and a crosslinking additive that bonds between the polymers of the soluble polyimide constituting the first alignment film. Additive, an adhesion assistant that increases the adhesion between the counter substrate and the first alignment film, an additive made of a conductive material, and an adhesion assistant that increases the adhesion between the element substrate and the first alignment film , Any one of the additives consisting of a cross-linking additive and a conductive material for bonding between the polymers of the soluble polyimide constituting the second alignment film is added,
  The second alignment film includes an adhesion assistant that enhances the adhesion between the counter substrate and the second alignment film, a crosslinking additive that bonds between the polymers of the soluble polyimide constituting the second alignment film, and A liquid crystal device, wherein any one of the conductive materials is added.   In a liquid crystal device in which an element substrate and a counter substrate facing the element substrate are arranged to face each other via a sealing material, and liquid crystal is interposed between the element substrate and the counter substrate.
A first alignment film for aligning the liquid crystal, formed on a side of the element substrate facing the liquid crystal;
A second alignment film that is formed on the opposite substrate facing the liquid crystal and that aligns the liquid crystal;
The first alignment film includes an adhesion assistant that enhances adhesion between the element substrate and the first alignment film, a cross-linking additive that bonds between the polymers of the soluble polyimide constituting the first alignment film, and Additive made of conductive material is added,
  The second alignment film includes an adhesion assistant that enhances the adhesion between the counter substrate and the second alignment film, and a crosslinking additive that bonds between the soluble polyimide polymers constituting the second alignment film. A liquid crystal device, wherein any one of an additive made of an additive made of a conductive material and an adhesion assistant that enhances adhesion between the counter substrate and the second alignment film is added .   2. The liquid crystal device according to claim 1, wherein the second alignment film is set to have a higher additive concentration of the additive than the first alignment film. The first alignment film and the second alignment film are characterized in that at least one addition concentration of the adhesion assistant, the crosslinking additive, and the conductive material is set to a different value. Item 6. The liquid crystal device according to Item 5 . In the first alignment film and the second alignment film, the number of constituents of the additive composed of at least one of the adhesion assistant, the crosslinking additive, and the conductive material is different. The liquid crystal device according to claim 5 .

Images