JP3867799B2 - Liquid crystal device - Google Patents

Description

  The present invention relates to a liquid crystal device in which a reflective film and a colored layer are formed on a surface of a substrate on the liquid crystal layer side, an electronic device including the liquid crystal device, and a substrate for a liquid crystal device.

  Conventionally, a reflection type liquid crystal device having an advantage of low power consumption is used for a portable information terminal or the like. In recent years, in particular, with the increase in the transmission and reception of image information, the color movement of reflective liquid crystal devices has increased.

  Here, in the liquid crystal device, the reflective liquid crystal device can be realized by providing the reflective film on either the outer surface or the inner surface of the liquid crystal layer. However, the configuration in which the reflective film is provided on the inner surface is based on parallax. This is preferable in that the deterioration of display quality such as double image and color blur can be suppressed. For example, in an active matrix liquid crystal device, the pixel electrode formed on the substrate on which the switching element is provided has reflectivity, and the pixel electrode is also used as a reflective film, so that a reduction in display quality is suppressed. Type color liquid crystal device can be realized.

  In recent years, in order to ensure visibility in a dark place, not only the light is reflected but also a reflective film is formed so as to transmit the light, so that both of the reflective display and the transmissive display are provided. A transflective liquid crystal device capable of display has been proposed. According to such a transflective liquid crystal device, low power consumption is usually achieved by using it as a reflective display, while visibility is improved by using it as a transmissive display as necessary in a dark place. Will be secured.

  However, in the configuration in which the pixel electrode is also used as the reflection film, aluminum generally used as the reflection film is exposed during the manufacturing process. As is well known, since aluminum lacks corrosion resistance, in such a configuration, aluminum may be damaged, and reflection characteristics as a reflective film, electrical characteristics as an electrode, and the like may deteriorate.

  For example, in the manufacturing process of the liquid crystal device, in the alignment film forming step, N-methylpyrrolidone (1-methyl-2-pyrrolidinone), γ-butyrolactone (4-hydroxybutyric acid γ-lactone), etc. And a step of heating from 150 ° C. to 250 ° C. after applying a solution mainly composed of polyimide or polyamic acid dissolved in a polar solvent to the substrate. For this reason, there is a high possibility that the aluminum is damaged.

  Furthermore, in the configuration in which the other electrode facing the reflective electrode is ITO (Indium Tin Oxide), there is a polarity difference between the aluminum electrode sandwiching the liquid crystal layer and the ITO electrode, so that only the display quality of the liquid crystal device is displayed. In addition, long-term reliability is also reduced. These phenomena occur in the same manner even in aluminum alloys containing other elements, although there are some magnitudes.

  Further, in the above-described transflective liquid crystal device, when a transmissive display is used, the contrast ratio is significantly reduced due to light leaked from outside the pixel, and a high-quality display cannot be performed. In order to prevent such a decrease in contrast ratio due to leakage light, a configuration in which a light shielding film is separately provided on a substrate opposite to the substrate on which the reflective film is provided, that is, on the substrate on the near side as viewed from the observer may be employed. .

  Here, as the light shielding film, it is common to use chromium or a black resin material. Among these, chromium has a high light-shielding property and can have a film thickness of 200 nm or less. However, since it is a metal material, it has a high surface reflectance. For example, single layer chrome has a reflectivity of about 60%, and low reflectivity double layer chrome has a reflectivity of about 7%. For this reason, when chromium is used for the light-shielding film, light incident from the observation side is reflected on the surface of the light-shielding film, resulting in a problem that the contrast ratio is lowered particularly in the reflective display.

  On the other hand, since the black resin material has a low reflectance, the surface reflectance can be suppressed. However, since the light shielding property is inferior, in order to ensure the optical density of 2 or more required in the transmissive display, the black resin material is black. The resin must be thickened. For this reason, there is a problem that not only the flatness of the substrate is deteriorated but also the patterning width cannot be narrowed, resulting in a small aperture ratio.

  The present invention has been made under such a background, and an object of the present invention is to provide a liquid crystal device, an electronic apparatus, and a substrate for a liquid crystal device having good reflection characteristics and display characteristics.

  In order to achieve the above object, in the liquid crystal device according to the first aspect of the present invention, the first transparent electrode formed on the first substrate side and the second formed on the second substrate side. A liquid crystal device in which a liquid crystal layer is sandwiched between the transparent electrode, and formed on a surface of the second substrate on the liquid crystal layer side, and reflects light incident from at least the first substrate side. And a light-shielding film formed on the surface of the second substrate on the liquid crystal layer side and having an opening region corresponding to an intersecting region of the first and second transparent electrodes, and the second substrate And a colored layer formed on the surface of the substrate on the liquid crystal layer side so as to cover the light shielding film.

  According to the first aspect, since the liquid crystal layer is sandwiched between the first and second transparent electrodes of the same type, the display quality and long-term reliability of the liquid crystal device do not deteriorate. Further, since the light shielding film and the colored layer are formed on the reflective film, the reflective film can be prevented from being exposed. For this reason, in the manufacturing process of the liquid crystal device, the reflection film can be prevented from being exposed to the chemical solution, the gas, the liquid crystal layer, and the like, and damage to the reflection film can be suppressed. Further, since the colored layer is formed so as to cover the light shielding film, not only the surface reflection at the light shielding film can be suppressed, but also the optical density required for the light shielding film can be reduced. In particular, in the reflective display, light passes through the light shielding film twice. Therefore, when the reflective display is mainly used, even if the optical density of the light shielding film is small, substantially sufficient light shielding properties can be obtained. .

  Here, in the first aspect of the invention, it is desirable that the first opening is provided in the opening region of the light shielding film and transmits light to the reflective film. In this configuration, since the reflective film does not function as an electrode, that is, the liquid crystal layer is driven by the second transparent electrode even in the first opening of the reflective film, transmission by light transmitted through the opening is performed. Type display is possible. Furthermore, in transmissive display, light is defined not by the opening region of the light shielding film but by the first opening provided in the reflective film, so that the optical density required for the light shielding film takes into account only the reflective display. Set it.

In the first invention, it is preferable that the first film is further provided between the reflective film and the surface of the second substrate on the liquid crystal layer side. According to this configuration, it is possible to improve the adhesion of the reflective film by the first film even in a combination where the adhesion between the metal used as the reflective film and the surface of the second substrate is inferior. Become. As described above, a metal, an oxide, or a nitride can be used as the first film that improves the adhesion of the reflective film. Among these, examples of the metal include transition metals included in the groups 5b to 6b such as Ta, Cr, Mo, and W. Examples of oxides include oxides of the above transition metals such as Ta ₂ O ₅ and silicon oxides such as SiO ₂ , and other examples include TiO ₂ , ZrO ₂ , these and SiO ₂ . Suitable combinations, Al ₂ O _{3 and the} like can be mentioned. Further, examples of the nitride include silicon nitride represented by Si ₃ N ₄ . Since this first film is for improving the adhesion of the reflective film, the film thickness is about 100 nm, and in some cases, about 30 to 60 nm is sufficient. Further, in the case of using a non-conductive SiO ₂ film, Ta ₂ O ₅ film, or the like, the film may remain on the entire surface of the second substrate, so that the film need not be patterned. For example, in the case where silver or a silver alloy containing silver as a main component is used as the reflective film and glass is used as the second substrate, Mo or Ta is used as the first film for improving adhesion. _It is desirable to use a ₂ O ₅ SiO ₂ film or the like. When a flexible substrate such as a plastic film is used as the insulating substrate, a SiO ₂ film, TiO ₂ , ZrO ₂ , an appropriate combination of these and SiO ₂ is used as the first film. Is desirable.

  In the first invention, the light shielding film is preferably made of a black resin material. Examples of such a black resin material include a color resist in which a black pigment is dispersed and a printable black paint. As described above, the black resin material is excellent in terms of low reflectance as compared with chromium, but is inferior in light shielding properties. However, in the first invention, as described above, since the optical density of the light shielding film can be small, it is not necessary to form the light shielding film thick. For example, when only transmissive display is considered, the light shielding film requires an optical density of 2 or more. To obtain this optical density with a black resin material, a film thickness of about 0.9 μm is required. is there. On the other hand, in the first invention, the colored layer is formed so as to cover the light shielding film, and further, light passes through the light shielding film twice in the reflective display, and the light is reflected in the transmissive display. Therefore, even if a black resin material is used for the light-shielding film, the required film thickness is 0.5 μm or less and can be almost halved. For this reason, in the first invention, even when a black resin material is used for the light shielding film, the flatness of the substrate is not deteriorated and the aperture ratio is not lowered. In general, the contrast ratio of the reflective display device is about 1:10 to 1:25, and this value is lower than that of the transmissive liquid crystal device. Therefore, the optical density is reduced in accordance with the liquid crystal mode to be used. It is also possible to further reduce the thickness of the black resin material.

  On the other hand, in the first invention, the light shielding film preferably has a configuration in which the colored layers are laminated in two or more colors. In this configuration, it is not necessary to provide a separate layer as the light shielding film, so that the cost can be reduced. The colored layer of a general reflective liquid crystal device is lighter than the colored layer of a transmissive display device, so even if two or more colored layers are stacked, the optical density may be 1 or less. It is difficult to obtain the necessary optical density. On the other hand, in this configuration, in the reflective display, light passes twice through the light-shielding film formed by stacking two or more colored layers, and in the transmissive display, light passes through the first opening of the reflective film. Therefore, sufficient light-shielding properties can be obtained even if a light colored layer is used. For example, when there are three colored layers of R (red), G (green), and B (blue), if the optical density when these three colored layers are stacked is 0.7, light is 2 Since the substantial optical density by passing the light is about 1.4, a reflection type liquid crystal device having a contrast ratio of 1:25 or less generally has a practically sufficient light shielding property.

  Further, in the case where the light shielding film is composed of a laminated portion of two or more colored layers, the colored region having a high concentration is partially provided at a certain ratio with respect to the opening region of the light shielding film. The average density of light that is reflected and colored inside may be set to a value suitable for reflective display. According to this configuration, the portion where the dark colored layer is laminated becomes the light shielding film, so that the optical density of the light shielding film can be further increased. For example, if the optical density of the portion where the three colored layers are laminated is 1.6, the substantial optical density due to light passing twice reaches about 3.0, so 1: 100 or more. Reflective display with a high contrast ratio is possible.

  As described above, in the first invention, it is preferable that the optical density of the light shielding film (by passing light once) is 0.5 or more and 1.7 or less. In the first invention, as described above, since light passes through the light-shielding film twice in the reflective display, even if the optical density is small, the optical density is substantially reduced (by passing light twice). This is because the value increases.

  By the way, in the first invention, the opening region of the light shielding film is a distance between the first and second transparent electrodes from the periphery of the region with respect to the intersecting region with the first and second transparent electrodes. A configuration in which the area is expanded to the outside of the region up to approximately half is preferable.

  Here, in the liquid crystal device, the designed pixel is a region where the first and second transparent electrodes overlap each other in plan view, but even outside the designed pixel region, a so-called oblique electric field is applied. There is a region where liquid crystal molecules are driven. Specifically, it is a portion in the first transparent electrode and in the second transparent electrode, and the distance between the electrodes (liquid crystal) from the end of the intersecting region of the first and second transparent electrodes. It has been confirmed by the present inventor that liquid crystal molecules are driven by an oblique electric field up to a portion corresponding to a distance corresponding to about ½ of the layer thickness. For example, in a certain liquid crystal mode, when the distance between the electrodes is 4.0 μm, the liquid crystal molecules are driven in a region from the end of the electrode to the vicinity of about 2.0 μm. Therefore, if the opening region of the light shielding film is expanded to a portion corresponding to this region and light is reflected by the reflective film, the substantial aperture ratio can be improved.

  For example, in a normally black mode liquid crystal device that displays black when no voltage is applied, when white display is performed by applying a voltage, liquid crystal molecules are obliquely applied in that region even if they are slightly apart from the designed pixel edge. Driven by. For this reason, if a reflective film is provided without providing a light-shielding film in the region, the area that substantially functions as a pixel is larger than the area of the designed pixel, resulting in an improved aperture ratio and a bright display. It can be realized.

  On the other hand, even within the designed pixel region, there is a region where liquid crystal molecules are not driven by a so-called oblique electric field. In such a region, a light shielding film is provided so that light is not reflected by the reflective film. In this case, it is possible to prevent a decrease in contrast ratio. For example, in a normally white mode liquid crystal device that performs white display when no voltage is applied, if a reflective film is disposed without providing a light shielding film in a region where liquid crystal molecules are not driven, even when black display is performed by voltage application, Since it is impossible to achieve complete black display, the contrast ratio is lowered. However, if such a region is not visually recognized by providing a light shielding film, it is possible to prevent the contrast ratio from being lowered. It becomes.

  Further, in a liquid crystal device using STN (Super Twisted Nematic) and using a normally white mode, when a certain pixel is displayed in black, it is not within the design pixel area, Although the phenomenon that the region where the liquid crystal molecules are not completely driven remains due to the influence of the oblique electric field may occur and the contrast ratio is lowered, the reflective film and the electrode are independent as in the first invention. In the configuration, it is possible to prevent a reduction in contrast ratio by hiding the region with a light shielding film. Further, even when outside the pixel region, a reflective film is disposed without providing a light-shielding film in a region where liquid crystal molecules are driven by an oblique electric field, so that a substantial aperture ratio is improved and bright. Display is possible.

  Such prevention of reduction in contrast ratio and substantial improvement in aperture ratio can be realized only when the reflective film and the pixel electrode are provided independently as in the first aspect of the invention. . Therefore, this point will be described once again with reference to the drawings. Here, FIG. 19A is a schematic plan view showing the configuration of a passive matrix type liquid crystal device using STN liquid crystal, and FIG. 19B shows the alignment direction of liquid crystal molecules adjacent to the substrate and the liquid crystal layer in the liquid crystal device. It is a schematic plan view which shows the orientation direction of the liquid crystal molecule in the bulk of. 19C is a schematic cross-sectional view taken along line GG-GG ′ in FIG. 19A when no voltage is applied, and FIG. 19D is a schematic cross-sectional view taken along line GG-GG ′ in FIG. 19A when voltage is applied. .

  As shown in FIG. 19A, in the passive matrix type liquid crystal device, the transparent electrode 22 provided on the upper substrate 21 and the transparent electrode 32 provided on the lower substrate 31 opposed thereto cross each other in plan view. The area to be used is the designed pixel area 50. Here, as shown in FIG. 19B, it is assumed that a counterclockwise STN liquid crystal mode is adopted by a combination of the rubbing direction 23 of the upper substrate 21 and the rubbing direction 33 of the lower substrate 31. In this case, the liquid crystal molecules 41 near the upper substrate 21 are aligned along the rubbing direction 23 of the upper substrate 21, and the liquid crystal molecules 42 near the lower substrate 31 are aligned along the rubbing direction 33 of the lower substrate 31. The liquid crystal molecules 43 in the bulk of the layer 40 are aligned in a direction orthogonal to the formation direction of the electrodes 32 of the lower substrate 31.

  Here, when no voltage is applied, the orientation of the liquid crystal molecules 43 in the bulk of the liquid crystal layer 40 is uniform as shown in FIG. 19C, but when the voltage is applied, the electrodes of the upper substrate 21 are shown in FIG. 19D. As a result, the electric lines of force 53 generated between the electrode 22 and the electrode 32 of the lower substrate 31 are distorted at the periphery of the pixel (that is, “an oblique electric field” is generated). 43 is disturbed, a reverse tilt domain is generated, and a region 51 in which the liquid crystal molecules 43 are not normally driven appears. On the other hand, at the other end of the pixel, a region 52 where the liquid crystal molecules 43 in the bulk are normally driven appears even outside the electrode 32 of the lower substrate 31.

  Accordingly, the light shielding film is extended to a position corresponding to the region 51 where the liquid crystal molecules 43 are not normally driven, while the reflection film is not provided at the position corresponding to the region 52 where the liquid crystal molecules 43 are normally driven. As a configuration in which light is reflected, it is possible to achieve a bright display by substantially improving the aperture ratio without lowering the contrast ratio. Such an effect is not possible with the conventional configuration in which the electrode has reflectivity, and can be realized only by providing the reflective film and the pixel electrode independently as in the first invention. is there.

  By the way, in the first invention, as the reflective film, a metal alloy or a single metal mainly composed of aluminum, silver, chromium or the like can be used. When a metal alloy containing aluminum as a main component is used as the reflection film, a reflection film having a relatively high reflectance can be realized with a low manufacturing cost. At this time, the aluminum content in the metal alloy is preferably 80% by weight or more. Further, when a metal alloy containing silver as a main component is used as the reflective film, the reflectance can be made extremely high. At this time, the ratio of silver in the metal alloy is preferably 80% by weight or more.

  In addition to glass or the like, a flexible substrate such as a plastic film can be used as the second substrate. When such a flexible substrate is used, a metal whose reflective film can be coated by electroless plating, such as a metal alloy mainly composed of nickel, can also be used.

  Here, in the first invention, when the metal used as the reflective film is likely to be damaged by a chemical solution or a gas when forming the colored layer, the second film covers at least the surface of the reflective film. The structure further comprising this film is preferable. In this configuration, it is desirable that the second film be within a range that does not significantly reduce the reflectance of the reflective film. In the first invention, since the colored layer substantially protects the reflective film, the second film is resistant to chemicals and gases exposed when the colored layer is formed. That is enough. For example, when the colored layer is formed on the reflective film by a printing method or a dyeing method, the second film is not particularly necessary, but the colored layer is formed by a colored photosensitive material method using a photosensitive color resist. In this case, depending on the material used, a strong alkaline developer may be used, so a second film is provided according to the combination of the developer and the metal used for the reflective film, and the reflective film It is preferable to have a configuration covering the surface.

  However, when an aluminum alloy, a silver alloy, or the like is used as the reflective film, the second film may be unnecessary. For example, when an aluminum alloy containing 1% by weight of neodymium is used as the reflective film, the corrosion resistance is improved. Therefore, a general solution using a mixed aqueous solution of sodium carbonate and sodium hydrogencarbonate or an aqueous solution of tetramethylammonium hydroxide is used. Since the developer having the composition is less susceptible to damage that causes a decrease in reflectance, it is not necessary to provide a second film that covers the surface of the reflective film.

  In addition, for example, when an aluminum alloy containing 3% by weight of neodymium or an aluminum alloy containing 3% by weight of neodymium and 3% by weight of titanium (Ti) is used as the reflective film, the corrosion resistance is further improved. No need to provide the second film.

Now, since it is necessary to form the 2nd transparent electrode on the surface which has a different characteristic called glass and a resin material, it is necessary to ensure a certain amount of adhesiveness with respect to these surfaces. Therefore, in the first invention, it is desirable that the second transparent electrode be formed on a third film that enhances adhesion. An example of such a third film is an inorganic oxide film typified by SiO _{2. In} particular, it is desirable to continuously form SiO ₂ and ITO as the second transparent electrode by sputtering or the like.

  By the way, in the first invention, in the configuration including the first opening in the reflective film, the fourth film formed so as to cover the colored layer and the opening region of the light shielding film, A configuration further comprising a second opening for opening the colored layer is preferable. This makes it possible to optimize the color reproducibility in the reflective display and the transmissive display.

  Alternatively, in the first invention, it is preferable to simply include a fourth film formed so as to cover the colored layer. By this fourth film, the presence or absence of the opening region of the light-shielding film, the step due to the colored layer, and the step due to the first opening in the reflective film are flattened. Therefore, it is possible to prevent the display quality from deteriorating.

  Here, the fourth film preferably has a light scattering property. According to this configuration, since the fourth film itself becomes a scattering layer, there is no need to provide a separate scattering layer. As a result, the number of steps can be reduced and the cost can be reduced.

  As such a fourth film, a configuration in which a resin material includes particles having a refractive index different from that of the resin material and smaller in diameter than the fourth film thickness is conceivable. Thereby, a reflective film having both flatness and scattering properties can be obtained.

  Examples of the resin material in the fourth film include an acrylic resin and a polyimide resin, and examples of the particles include inorganic particles such as glass beads and organic polymer particles such as polystyrene spheres. The scattering characteristics can be controlled by the film thickness of the resin material, the refractive index difference, the particle diameter, the degree of dispersion of the particles, and the like.

  At this time, it is desirable that the light scattering characteristics have a haze value in the range of 40 to 90% and a refractive index difference in the range of 0.05 to 0.12. For example, the refractive index of a material considered as a resin material is around 1.50 for PMMA (polymethyl methacrylate) and around 1.60 to 1.65 for a polyimide resin, while the refractive index of a material considered as a particle is PTFE (4-fluoroethylene) is around 1.35, PVDF (vinylidene fluoride) is around 1.42, LF1 optical glass is around 1.57, styrene is around 1.59, F2 optical glass Is around 1.62, and SF2 optical glass has a value such as 1.65. For this reason, it becomes possible to obtain a desired scattering function by appropriately combining these. In addition, the refractive index of the material mentioned here may become a value which changes with the manufacturing methods and forms. These are some of the materials that can be used, and the first invention is not limited to this, and it is needless to say that materials having various characteristics can be used in combination.

  In the first invention, the reflection film is preferably formed on a rough surface. Even with this configuration, since the second substrate side has scattering characteristics, it is not necessary to provide a separate scattering layer. As a result, the number of steps can be reduced and the cost can be reduced. Furthermore, since the rough surface is flattened by the fourth film, it is possible to prevent the display quality from being deteriorated due to the level difference caused by the rough surface. For example, in order to give the reflective film good scattering characteristics, when a rough surface is formed by providing a large number of peaks and valleys having a difference of 0.3 μm to 1.5 μm, the thickness of the liquid crystal layer is partially determined depending on the shape. Since the pretilt angle of the liquid crystal molecules changes, it may not be possible to obtain good display characteristics. However, in this configuration, since the fourth film is flattened, the flatness of the second transparent electrode Can be secured. This configuration is effective for a TN (Twisted Nematic) mode having a twist angle of 100 degrees or less, but particularly effective in combination with an STN mode that requires high accuracy with respect to the thickness of the liquid crystal layer. is there.

  Here, a configuration in which the rough surface is a surface of a resin material formed on the surface of the second substrate on the liquid crystal layer side is conceivable. As such a resin material, a photosensitive resin such as acrylic or polyimide is useful. Since these resin materials have high heat resistance, they have sufficient resistance to the formation process of the reflective film, the colored layer, the second transparent electrode, and the like. The photosensitivity may be a negative type or a positive type. Further, for the formation of the rough surface, the surface mold having a large number of peaks and valleys is brought into close contact with the surface coated with the resin material, and pressure is applied to transfer the shape of the surface to the surface of the resin material. The pressing method can also be used.

  Further, the rough surface may be configured by roughening the surface on the liquid crystal layer side of the second substrate. Examples of the surface roughening treatment include a method of applying and baking a sol-gel solution in which particles are dispersed, a method of etching a substrate surface non-uniformly, and the like. In particular, when the second substrate is a glass substrate, after forming an oxide film on the surface of the substrate, the first method of etching non-uniformly due to the non-uniform composition of the oxide film, or aluminum contained in the substrate itself Or a second method of etching non-uniformly with an etchant that dissolves high-concentration parts such as boron and sodium, and the composition is deposited by immersing the substrate composition in a supersaturated hydrofluoric acid aqueous solution. A third method for etching non-uniformly by an LPD (Liquid Phase Deposition) method can be used. Among these, the second and third methods are advantageous in terms of cost reduction because they do not require a coating process or a sputtering process and only need to be immersed in a chemical solution.

  In the electronic apparatus including the liquid crystal device according to the first aspect of the invention, a reflective display with high brightness and high display quality is possible, while a transmissive display is possible as necessary. Excellent visibility even in the environment.

  The above object can also be achieved on the second substrate side of the liquid crystal device according to the first invention. That is, the substrate for a liquid crystal device according to the second invention of the present application is a substrate for a liquid crystal device located on the opposite side to the observation side of the pair of substrates sandwiching the liquid crystal layer, wherein the liquid crystal layer A reflective film that is formed on the surface on the side and reflects at least light incident from the observation side; a light-shielding film that is formed on the surface on the liquid crystal layer side and has an opening region that opens to the reflective film; and the liquid crystal A colored layer formed on the layer side surface so as to cover the light shielding film and a transparent electrode formed on the colored layer are provided.

According to the second aspect of the invention, the liquid crystal layer can be held between the transparent electrodes of the same type by being bonded to the substrate located on the observation side, so that the display quality and long-term reliability of the liquid crystal device do not deteriorate. . Moreover, since the light shielding film and the colored layer are formed on the reflective film , damage to the reflective film can be suppressed. Further, since the colored layer is formed so as to cover the light shielding film, not only the surface reflection at the light shielding film can be suppressed, but also the optical density required for the light shielding film can be reduced.

  Here, in the second aspect of the present invention, it is desirable that the first opening is provided in the opening region of the light shielding film and transmits light to the reflective film. In this configuration, since the reflective film does not function as an electrode, that is, the liquid crystal layer is driven by the transparent electrode even in the first opening of the reflective film, a transmissive display by light transmitted through the opening is possible. Further, in the transmissive display, light is defined not by the opening area of the light shielding film but by the first opening provided in the reflective film, so that the optical density required for the light shielding film can be set only for the reflective display. This should be set in consideration of the above.

  In the second invention, it is preferable that the first film is further provided between the reflective film and the liquid crystal layer side surface. According to this configuration, the first film can improve the adhesion of the reflection film even if the adhesion between the metal used for the reflection film and the surface of the second substrate is inferior. Become.

  In the second invention, preferably, the light shielding film is made of a black resin material and has an optical density of 0.5 or more and 1.7 or less. According to this configuration, even when a black resin material is used for the light shielding film, the flatness of the substrate is not deteriorated, and the aperture ratio is not lowered.

  On the other hand, in the second invention, it is also preferable that the light-shielding film is formed by laminating two or more colored layers and having an optical density of 0.5 or more and 1.7 or less. In this configuration, it is not necessary to provide a separate layer as the light shielding film, so that the cost can be reduced.

  In the second invention, it is preferable that the second film further cover at least the surface of the reflective film. According to this configuration, since the metal used as the reflective film is not directly exposed to the chemical liquid or gas when forming the colored layer, it can be prevented from being damaged.

  In the second invention, it is preferable that the transparent electrode is formed on a third film that improves adhesion. According to this configuration, it is possible to form the transparent electrode while ensuring adhesion to a surface having characteristics different from that, such as glass or a resin material.

  By the way, in the second invention, in the configuration including the first opening in the reflective film, the fourth film formed so as to cover the colored layer, and the opening region of the light shielding film, A configuration further comprising a second opening for opening the colored layer is preferable. This makes it possible to optimize the color reproducibility in the reflective display and the transmissive display.

  Alternatively, in the second invention, it is preferable to simply include a fourth film formed so as to cover the colored layer. By this fourth film, the presence or absence of the opening region of the light-shielding film, the step due to the colored layer, and the step due to the first opening in the reflective film are flattened. Therefore, it is possible to prevent the display quality from deteriorating.

  Here, the fourth film preferably has a light scattering property. According to this configuration, since the fourth film itself becomes a scattering layer, there is no need to provide a separate scattering layer. As a result, the number of steps can be reduced and the cost can be reduced.

  As such a fourth film, a configuration in which a resin material includes particles having a refractive index different from that of the resin material and smaller in diameter than the fourth film thickness is conceivable. Thereby, a reflective film having both flatness and scattering properties can be obtained.

  In the second invention, it is also preferable that the reflective film is formed on a rough surface on the liquid crystal layer side. Even with this configuration, since the substrate itself has scattering characteristics, there is no need to provide a separate scattering layer. As a result, the number of steps can be reduced and the cost can be reduced. Furthermore, since the rough surface is flattened by the fourth film, it is possible to prevent the display quality from being deteriorated due to the level difference caused by the rough surface.

  Here, a configuration in which the rough surface is a surface of a resin material formed on the surface on the liquid crystal layer side, a configuration in which the surface on the liquid crystal layer side is roughened, or the like can be considered.

The liquid crystal device of the present invention, a liquid crystal layer sandwiched between the first substrate and the second substrate, Ri Na has a plurality of pixel regions, the light incident from the observation side in the plurality of pixel areas A liquid crystal device that performs a reflective display to be reflected and a transmissive display in which light incident from the back side is transmitted through the plurality of pixel regions, and a light-shielding film having an opening region corresponding to the plurality of pixel regions; The light shielding film overlaps with the light shielding film so as to be on the observation side with respect to the reflective film over the entire circumference of the opening area of the light shielding film, and within the opening area of the light shielding film in the opening area of the light shielding film wherein a reflection film provided on a part of, the opening area of the light shielding film, the reflective film and a part of the reflective film is provided region is provided so as to overlap the region not provided, and , colored layer provided so as to overlap the entirety of the light shielding film , Comprising a, the opening area of the light shielding film, the light transmission characteristics showing a relationship between transmittance for the wavelength of light to be colored by the coloring layer located in a region where the reflective film is not provided in the transmissive display And the light that is colored by the colored layer located in the area where the reflective film is provided in the reflective display and the light that is not colored by the area where the colored layer is not provided in the area where the reflective film is provided The light transmission characteristic is different from the light transmission characteristic indicating the relationship of the transmittance with respect to the wavelength of the average light, and the light colored by the colored layer located in the region where the reflection film is provided in the reflective display and the reflection film are provided. From the transmittance in the light transmission characteristics of the average light which the coloring layer in the region has rolled the light which is not colored by not forming region, it said in transmissive display reflective film Higher than the minimum transmittance in the light transmission characteristics of light colored by the colored layer located provided non region characterized.

  Further, the thickness of the colored layer located on the opening of the reflective film is formed to be thicker than the thickness of the colored layer located on a portion other than the opening of the reflective film. To do.

  According to another aspect of the present invention, there is provided an electronic apparatus including the above liquid crystal device.

Further, the substrate in the liquid crystal device of the present invention is a substrate for a liquid crystal device located on the side opposite to the observation side among the pair of substrates sandwiching the liquid crystal layer, and is formed on the surface on the liquid crystal layer side, A reflection film that reflects at least light incident from the observation side; a light-shielding film that is formed on a surface on the liquid crystal layer side and that has an opening region that opens to the reflection film; and A first opening that is provided in the reflective film and transmits light; a colored layer formed on the reflective film in the opening area of the light shielding film; and the colored layer in the opening area of the light shielding film. A second opening provided, a protective film formed so as to cover the colored layer, and a transparent electrode formed on the protective film, wherein the colored layer includes the first layer of the reflective film. The colored layer is formed so as to cover the opening of 1 The second opening may be configured as being provided on the first portion except the opening of the reflective film in the opening area of the light shielding film.

Further, the substrate in the liquid crystal device of the present invention is a substrate for a liquid crystal device located on the side opposite to the observation side among the pair of substrates sandwiching the liquid crystal layer, and is formed on the surface on the liquid crystal layer side, At least a reflective film that reflects light incident from the observation side, a first opening that is provided in the reflective film and transmits light, a colored layer formed on the reflective film, and provided in the colored layer And a transparent electrode formed on the colored layer, wherein the colored layer is formed so as to cover the first opening of the reflective film, and the colored layer is formed. The second opening of the layer can be configured to be provided on a portion of the reflective film excluding the first opening.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

<First Embodiment>
First, the reflective liquid crystal device according to the first embodiment of the present invention will be described. For convenience, first, the schematic configuration of the liquid crystal device will be described with reference to FIG. 1, and second, of the pair of substrates in the liquid crystal device, positioned on the back side (the side opposite to the observation side). 2 to 6 will be described with reference to FIGS. 2 to 6, and the positional relationship of the light shielding film in each embodiment will be described with reference to FIGS. 7 to 9. Examples and modifications will be described.

First, a schematic configuration of the liquid crystal device will be described. FIG. 1 is a schematic sectional view thereof. As shown in this figure, in this liquid crystal device, a predetermined twist is provided between an upper substrate (first substrate) 101 and a lower substrate (second substrate) 1 having transparency and insulation, respectively. A liquid crystal layer 58 that is a nematic liquid crystal having a corner is sealed with a frame-shaped sealing material 59, thereby forming a liquid crystal cell. Here, on the inner surface of the upper substrate 101, a plurality of striped electrodes (first transparent electrodes) 110 made of a conductive layer having transparency such as ITO are formed in the direction perpendicular to the paper surface. An alignment film 112 is formed on the surface and rubbed in a predetermined direction. On the other hand, on the outer surface of the substrate 101, a front scattering plate 121, a phase difference plate 123, and a polarizing plate 125 are arranged in this order from the substrate 101 side.

  A reflective film 2, a protective film 3, a light shielding film 13, a colored layer 4, a protective film 6, an adhesion improving layer 5 and an electrode 7 are sequentially formed on the inner surface of the lower substrate 1. Although these details will be described in detail, the electrode (second transparent electrode) 7 is made of the same material as the electrode 110 formed on the upper substrate 101, that is, a conductive layer having transparency such as ITO. A plurality of stripes are formed in the left-right direction on the paper surface so as to intersect with each other. Therefore, in this liquid crystal device, a region where the electrodes 7 and 110 intersect with each other is a designed pixel. A region 9 indicates a region where the designed pixels are arranged, that is, a display region.

On the other hand, the reflection film 2 is made of a reflective metal layer such as aluminum or silver, and reflects light incident from the upper substrate 101. Next, the protective film (second film) 3 is formed according to the properties of the reflective film 2 as will be described later. The light-shielding film 13 is made of a light-shielding material such as a black material resin or chrome, and opens corresponding to the intersecting region of the electrodes 7 and 101. Further, the colored layer 4 is formed by arranging, for example, three colors of R (red), G (green), and B (blue) in a predetermined pattern in the opening region of the light shielding film 13. Subsequently, the protective film (fourth film) 6 has a function of flattening a step due to the colored layer 4 and the light shielding film 13 and a function of protecting the reflective film 2 together with the colored layer 4. Next, the adhesion improving layer (third film) 5 is formed on the entire surface including the surface of the protective film 6 and is provided to improve the adhesion of the electrode 7, and is an inorganic material such as SiO _2. It consists of an oxide film. An alignment film 11 is formed on the surface of the adhesion improving layer 5 and the electrode 7 and is rubbed in a predetermined direction.

  In such a configuration, external light reaches the reflective film 2 through a path of the polarizing plate 125, the retardation plate 123, the forward scattering plate 121, the substrate 101, the electrode 110, the liquid crystal layer 58, the electrode 7, and the colored layer 4. Then, the light is reflected here, and the current path is traced in the reverse direction and emitted from the polarizing plate 125 to the observation side. At this time, the amount of light emitted from the polarizing plate 125 is set to a bright state, a dark state, and an intermediate brightness state according to the voltage applied to the liquid crystal layer 58 by the electrodes 7 and 110. Therefore, a desired display can be achieved by controlling the voltage applied to the liquid crystal layer 58.

  Therefore, according to this liquid crystal device, since the liquid crystal layer 58 is sandwiched between the electrodes 7 and 110 made of the same ITO, display quality and long-term reliability are not deteriorated. Further, since the light shielding film 13 and the colored layer 4 are formed on the reflective film 2, the reflective film 2 can be prevented from being exposed. For this reason, in the manufacturing process of the liquid crystal device, the reflection film 2 is not exposed to the chemical solution, the gas, the liquid crystal layer, and the like, so that damage to the reflection film 2 can be suppressed. Furthermore, since the colored layer 4 is formed so as to cover the light shielding film 13, not only the surface reflection at the light shielding film 13 is suppressed, but also the optical density required for the light shielding film 13 is small. In particular, since light passes through the light shielding film twice in the reflective display, the substantial optical density of the light shielding film 13 may be small.

  Although this liquid crystal device is a passive matrix system, the present invention is not limited to this, and a three-terminal switching element represented by a TFT (Thin Film Transistor) element or a TFD (Thin Film Diode) element is used. The present invention can also be applied to an active matrix liquid crystal device using a representative two-terminal switching element. Here, in the case of an active matrix liquid crystal device, the electrode 110 is formed as, for example, a rectangular pixel electrode and is connected to a wiring through a switching element. Among these, in the liquid crystal device including the TFD element, the electrode 7 needs to be patterned in a stripe shape so as to face the pixel electrode. However, in the liquid crystal device including the TFT element, it is not necessary to pattern the electrode 7.

  By the way, in this embodiment, the inner surface structure of the lower substrate 1 is not limited to that shown in FIG. 1, and various modes can be applied. Therefore, the details of these aspects will be described in a form in which the alignment film 11 is omitted.

  FIG. 2 is a schematic cross-sectional view showing the configuration of this aspect. First, a reflective film 2 containing aluminum as a main component is formed on the inner surface side of a substrate 1 such as glass having insulating properties and transparency, that is, on the surface side facing the upper substrate 101. The reflective film 2 is patterned by a photolithography method or the like so as to include the display region 9 of the liquid crystal device.

  Next, on the patterned reflective film 2, a light shielding film 13 made of a black resin material is formed with a thickness of about 0.6 μm. Further, a colored layer 4 made of a resin material is formed by, for example, R Three colors of (red), G (green), and B (blue) are arranged in a predetermined pattern, and are formed so as to cover the entire surface of the reflective film 2 including the light shielding film 13. Thereby, the colored layer 4 substantially functions as a protective film for the reflective film 2.

At this time, the optical density (Optical Density) of only the light shielding film 4 is 1.4. The optical density is a value obtained by logarithmically representing the reciprocal of the transmittance of the light-shielding film 13 that is a measurement object. That is, the optical density D is expressed by the following equation when the intensity of light incident on the light shielding film 13 is I ₀ and the intensity of light passing through the light shielding film 13 is I.

D = log ₁₀ (I ₀ / I)
Subsequently, an adhesion improving layer 5 and an ITO film, which is a transparent metal, are continuously formed. Of these, the ITO film is patterned in accordance with a liquid crystal device to be applied to form an electrode 7. Among these, the adhesion improving layer 5 is an inorganic oxide film such as SiO ₂ having a thickness of about 20 to 80 nm provided to ensure adhesion between the electrode 7 made of ITO and the colored layer 4 made of a resin material. is there. For this reason, when ITO has sufficient adhesiveness, this adhesion improving layer 5 can be omitted.

  In such a configuration, since a black resin material is used as the light shielding film 13, when this is used as a substrate located on the back side of a pair of substrates constituting the liquid crystal device, the surface reflectance is reduced. It becomes small and it can prevent that a contrast ratio falls in a bright place. Here, although the optical density of only the light shielding film 13 is 1.4, the colored layer 4 is provided so as to cover the light shielding film 13, and light passes through the light shielding film 13 twice in the reflective display. The substantial optical density of 13 is 2.8 or more, which is sufficient for reflective display.

When a metal containing aluminum as a main component is used as the reflective film 2, the surface of the reflective film 2 may be covered with a protective film 3 as shown in FIG. 3. Here, the protective film 3 is formed by anodizing the patterned reflective film 2. As the chemical conversion solution in this anodic oxidation, a mixed solution containing 1 to 10% by weight of ammonium salicylate and 20 to 80% by weight of ethylene glycol is used, the chemical conversion voltage is 5 to 250 V, and the current density is 0.001 to 1 mA. It may be set so as to obtain a desired film thickness within the range of the condition of / cm ² . The chemical conversion solution is not limited to the above mixed solution, and each condition of the chemical conversion voltage and the current density may be appropriately set according to the chemical conversion solution to be used.

On the other hand, as the reflective film 2, it is possible to use aluminum, a simple metal such as chromium, nickel, silver, or an alloy containing any of these as a main component. Among these, in particular, when silver alone or an alloy containing this as a main component is used as the reflective film 2, the reflectance can be increased, but anodization becomes difficult. Therefore, in forming the protective film 3, For example, chemical vapor deposition, spin coating, roll coating, or the like is used. As the protective film 3, SiO ₂ or Si ₃ N ₄ can be used when it is formed by chemical vapor deposition, and when it is formed by spin coating or roll coating, An organic insulating film will be used.

Thus, when the protective film 3 is formed by a method that is not anodized, it is provided not only on the exposed surface of the reflective film 2 but also on the entire inner surface of the substrate 1 as shown in FIG. . Even when a metal containing aluminum as a main component is used as the reflective film 2, the protective film 3 may be formed by a chemical vapor deposition method such as SiO ₂ or Si ₃ N ₄ , a spin coating method or a roll. Of course, an organic insulating film formed by a coating method or the like may be used as shown in FIG.

When the STN mode or the IPS (In Plain Switching) mode is used as the liquid crystal device, flatness is required for the surface on which the electrode 7 is formed. In such a case, the colored layer 4 in FIG. As shown in FIG. 5, it is preferable that a protective film 6 is separately provided between the adhesive improvement layer 5 and the adhesive improvement layer 5. More specifically, the protective film 3 made of SiO _{2 having} a thickness of 60 nm is formed on the patterned reflective film 2 by chemical vapor deposition, and then the light-shielding film 13 made of a black resin material is formed. Is formed. Here, the thickness of the light shielding film 13 is about 0.4 μm, which is thinner than those in FIGS. 2 to 4. Subsequently, the colored layer 4 formed so as to cover the entire surface of the reflective film 2 including the light shielding film 13 is further covered with a protective film 6 made of a photosensitive acrylic resin so as to cover the entire colored layer 4. It is formed in a specific area.

  In such a configuration, since the light-shielding film 13 is as thin as about 0.4 μm, the optical density of only the light-shielding film 13 is also as low as 0.9. However, the colored layer 4 and the protective film cover the light-shielding film 13. 6 and light passes through the light-shielding film 13 twice, so that the substantial optical density of the light-shielding film 13 is 1.8 or more sufficient for the reflective display. Further, by making the light shielding film 13 thin, the flatness on the surface on which the electrode 7 is formed can be suppressed within 0.1 μm in the display region 9.

By the way, in the aspect mentioned above, although the reflecting film 2 was formed directly on the upper surface of the board | substrate 1, when the adhesiveness of the reflecting film 2 becomes a problem, as shown in FIG. An adhesion improving layer (first film) 8 for improving the adhesion of the reflective film 2 may be separately provided between the substrate 1 and the upper surface of the substrate 1. Here, as the adhesion improving layer 8, a metal, an oxide, or a nitride can be used. Among these, examples of the metal include transition metals included in the groups 5b to 6b such as Ta, Cr, Mo, and W. Examples of oxides include oxides of the above transition metals such as Ta ₂ O ₅ and silicon oxides such as SiO ₂ , and other examples include TiO ₂ , ZrO ₂ , these and SiO ₂ . Suitable combinations, Al ₂ O _{3 and the} like can be mentioned. Further, examples of the nitride include silicon nitride represented by Si ₃ N ₄ . Since the adhesion improving layer 8 is for improving the adhesion of the reflective film 2, a film thickness of about 100 nm, or about 30 to 60 nm is sufficient in some cases. Further, when a non-conductive SiO ₂ film or Ta ₂ O ₅ film is used, the adhesion improving layer 8 may remain on the entire upper surface of the substrate 1. It is not necessary to pattern the enhancement layer 8. For example, in the case where silver or a silver alloy containing silver as a main component is used as the reflective film 2 and glass is used as the substrate 1, Mo or Ta ₂ O ₅ SiO ₂ film is used as the adhesion improving layer 8. Etc. are desirable. In the case where a flexible material such as a plastic film is used for the substrate 1, an SiO ₂ film, TiO ₂ , ZrO ₂ , an appropriate combination of these and SiO ₂ is used as the adhesion improving layer 8. Is desirable. Of course, such an adhesion improving layer 8 may be provided not only on the substrate shown in FIG. 5, but also on the substrate shown in FIG. 2, FIG. 3 or FIG.

  In the reflective display, it is preferable that light is appropriately scattered and emitted from the polarizing plate 125 on the upper substrate 101 side. For this reason, in the configuration shown in FIG. 1, the front scattering plate 121 is provided on the outer surface of the upper substrate 101. With respect to this scattering function, the reflective film 2 is attached to the substrate 1 as in the application example described later. In addition to forming on a rough surface, the protective film 6 can be configured as shown in FIG.

  That is, the protective film 6 shown in this figure is obtained by dispersing particles 6b of a material having a different refractive index from a resin material 6a such as a photosensitive acrylic resin. About these resin material 6a and particle | grains 6b, it is desirable to combine a material so that both refractive index difference may be in the range of 0.05-0.12. For example, when a combination of dispersing PVDF (polyvinylidene fluoride) particles as the particles 6b in a PMMA (polymethyl methacrylate) resin as the resin material 6a, a refractive index difference of about 0.8 is obtained. Of course, the combination is not limited to this, and any suitable combination of materials can be used so that a desired refractive index difference and scattering degree can be obtained. Since such a protective film 6 has a light scattering function due to Mie scattering, the front scattering plate 121 in FIG. 1 can be omitted.

  In addition, as the protective film 6 in FIG. 5 or FIG. 6, a resin material having photosensitivity other than the photosensitive acrylic resin can be used. Even when the protective film 6 is provided only in a specific region, when a printing method or a transfer method is used, or when the protective film 6 may be provided on the entire surface of the substrate 1, the protective film As 6, a sol-gel film or an organic protective film having no photosensitivity can be used.

  Next, the positional relationship in the light shielding film 13, particularly the positional relationship between the opening region of the light shielding film 13 and the electrode 7 will be described. Here, FIG. 7A is a schematic plan view showing the arrangement of the light shielding film 13 and the colored layer 4 formed on the inner surface of the lower substrate 1, and FIG. 7B shows a line AA ′ in FIG. 7B. These figures are both schematic cross-sectional views, and both figures show the structure of the stage where the colored layer 4 is formed. 7C is a schematic cross-sectional view showing a configuration in which up to the electrode 7 is formed on the substrate shown in FIG. 7B.

As shown in these drawings, the opening region of the light shielding film 13 is provided for each region 20 that can effectively drive the liquid crystal layer. Here, in the substrate shown in FIGS. 7A, 7B, and 7C, the region 20 is provided on the electrode 7 provided on the lower substrate 1 and the upper substrate 101 when configured as a liquid crystal device. This is a crossing region with the electrode 110 and corresponds to a designed pixel. That is, the region 20 in these drawings is a rectangular region defined by the length L ₁ and the width W ₁ when the width of the electrode 7 is L ₁ and the width of the electrode 110 is W ₁ .

Note that, as described with reference to FIG. 19D, there is a region where liquid crystal molecules are driven by an oblique electric field even outside the intersecting region (referred to as region A here for convenience). Even within the region, there are regions where the liquid crystal molecules are not normally driven (for convenience, referred to as region B). Strictly speaking, it is necessary to provide an opening region of the light shielding film 13 in consideration of these regions. There is. However, if the region 20 (length L ₁ and width W ₁ ) is sufficiently larger than the thickness d of the liquid crystal layer (see FIG. 1), the regions A and B can be ignored. For the substrates shown in FIGS. 7A, 7B, and 7C, it is assumed that the region 20 (length L ₁ and width W ₁ ) is sufficiently larger than the thickness d of the liquid crystal layer, and the regions A and B are ignored and light shielding is performed. The opening area of the film 13 is set.

Therefore, this time, the substrate in which the opening region of the light shielding film 13 is set in consideration of the regions A and B will be described. First, when the regions A and B are considered, the opening region of the light shielding film 13 is the region A at the intersection region of the electrodes 7 and 110 when the two substrates 1 and 101 are bonded as a liquid crystal device. The added region refers to a region excluding the region B, and is a rectangular region 12 defined by a length L ₂ and a width W ₂ in FIG. 8A. Here, FIG. 8A is a partial plan view showing the arrangement of the light shielding film 13 and the colored layer 4 formed on the inner surface of the lower substrate 1, and FIG. 8B shows the line EE ′ in FIG. 8A. FIG. 8C is a schematic cross-sectional view, and FIG. 8C is a schematic cross-sectional view taken along line FF ′ in FIG. 8A. As shown in these figures, the opening region 12 of the light shielding film 13 in consideration of the regions A and B is a designed pixel region 9c (a rectangular region defined by a length L ₁ and a width W ₁ ). On the other hand, one of the sides orthogonal to the director direction of the liquid crystal molecules in the bulk of the liquid crystal layer is narrowed by the length d ₁ , and the other side is wide by the length d ₂ . Therefore, the region widened by the length d ₂ corresponds to the region A where the liquid crystal molecules are driven by the oblique electric field, and the region narrowed by the length d ₁ is the region B where the liquid crystal molecules are not driven by the oblique electric field. Equivalent to. Here, the lengths d ₁ and d ₂ will be described in detail. When two substrates 1 and 101 are bonded as a liquid crystal device as shown in FIG. 1, the distance between the electrodes 7 and 110 (that is, When the thickness of the liquid crystal layer 58 is represented by d, the length d ₁ is approximately equal to or less than the distance d, and the length d ₂ is approximately 1/2 or less of the distance d. .

  In this configuration, since the light shielding film 13 is opened in the region A even outside the intersecting region 9c with the electrodes 7 and 110, the light is reflected by the reflective film 2, so that the substantial aperture ratio is improved. On the other hand, even within the intersecting region 9c, since the light shielding film 13 is provided in the region B, it is possible to suppress a decrease in contrast ratio due to the liquid crystal molecules not being driven.

Note that the direction and area of the area A to be enlarged and the direction and area of the area B to be reduced with respect to the intersecting area 9c of the electrodes 7 and 110 vary depending on the liquid crystal mode used and the rubbing direction with respect to the substrates 1 and 101. In any case, the opening region 12 in the light-shielding film 13 has a length that is approximately ½ of the distance d from the inside by a length d ₁ that is approximately the same as the distance d with respect to the region 9c. Patterning is performed so as to extend outward by d ₂ (see FIGS. 9A, 9B, and 9C). That is, the length L ₂ and the width W ₂ of the opening region 12 in the light shielding film 13 are within the following ranges, respectively.

L ₁ −2 · d ₁ ≦ L ₂ ≦ L ₁ + 2 · d ₂ W ₁ −2 · d ₁ ≦ W ₂ ≦ W ₁ + 2 · d ₂ <Application / Modification of First Embodiment>
By the way, in the example mentioned above, although the light shielding film 13 was formed from the black resin material, you may form as follows. That is, a separate layer is not provided as the light-shielding film 13, but a portion where three colored layers 4 of R (red), G (green), and B (blue) are stacked is used as the light-shielding film 13. Such a configuration will be described with reference to FIGS. 10A, 10B, and 10C. Here, FIG. 10A is a partial plan view showing the same configuration, FIG. 10B is a schematic cross-sectional view taken along line WW ′ in FIG. 10A, and FIG. 10C is a line XX ′ in FIG. 10A. It is a schematic sectional drawing about a line.

  As shown in these drawings, on the patterned reflective film 2, the color sensitization is performed so that the photosensitive color resists of R, G, and B are overlapped in order and in the portion that should become the light shielding film 13. Patterning is performed using a material method. As a result, the portion where the colored layers 4 are laminated for three colors becomes black due to additive color mixing and functions as the light shielding film 13, while the portion of only one color is the same as the above-described example. It functions as the opening region 12. And the protective film 6 is formed so that these surfaces may be covered, and the flattening of the part in which the colored layer 4 was laminated | stacked and the part which is not so with the protection of these is achieved.

  Here, the optical density of the portion where the colored layers 4 are laminated for three colors is about 0.7, but since this portion is originally the colored layer 4, its surface reflectance is small. For this reason, there is no adverse effect such as a decrease in contrast ratio in a bright place. Further, in the reflective display, since the colored layer 4 is laminated for three colors and passes through the portion that becomes the light shielding film 13 twice, the optical density of the light shielding film 13 is substantially 1.4 or more. Thus, it has a sufficient light shielding property in the reflective display. Furthermore, since a step of providing a separate layer as the light shielding film 13 is omitted, the cost can be reduced accordingly.

  In addition, in these figures, since it is the same as that of another structure and what was demonstrated, suppose that the same code | symbol is attached | subjected and the description is abbreviate | omitted. Further, in the configuration in which the portion where the colored layers 4 are laminated for three colors is used as the light shielding film 13, the above-described protective films 3 and 6 and the adhesion improving layers 5 and 8 can be appropriately selected and applied. The opening region of the light shielding film 13 can also be the one described with reference to FIGS. 7 and 8 in addition to FIG.

  Now, with respect to the configuration in which the lower substrate 1 has light scattering characteristics, the configuration shown in FIGS. 11A, 11B, and 11C can be used in addition to the configuration shown in FIG. Here, FIG. 11A is a partial plan view showing the configuration of the substrate having light scattering characteristics, FIG. 11B is a schematic cross-sectional view taken along line CC-CC ′ in FIG. 11A, and FIG. 11C is FIG. It is a schematic sectional drawing about the line DD-DD 'in FIG.

  As shown in these drawings, a rough surface layer 16 having a rough surface on the upper side is formed on the substrate 1, and a reflective film 2 is formed on the rough surface. Here, the rough surface layer 16 is, for example, a photosensitive resin mainly composed of acrylic, and after being coated on the substrate 1, a photo using a predetermined photomask so as to have the following structure. Patterned by a lithography method. That is, the rough surface of the rough surface layer 16 has a peak-to-valley difference of 0.2 μm to 1.5 μm, a peak-to-valley pitch of 2 μm to 15 μm, and is patterned into random peak-and-valley shapes. It is a thing.

  In such a configuration, the reflective film 2 reflects the rough surface of the rough surface layer 16, and reflects incident light from the upper substrate 101 side at a random angle. Only by this, an appropriate scattering characteristic can be provided. Further, in such a configuration, the surface of the reflective film 2 reflects the rough surface of the rough surface layer 16, but the colored layer 4 and the protective film 6 formed so as to cover the surface of the reflective film 2. Since the planarization is performed, the electrode 7 is formed on the flat surface without reflecting the rough surface.

  11A, 11B, and 11C are the same as the other configurations and those described, the same reference numerals are given and the description thereof is omitted. In these drawings, a portion where three colored layers 4 are laminated is used as the light shielding film 13, but it is needless to say that a black resin material may be used. Furthermore, the protective films 3 and 6 and the adhesion improving layers 5 and 8 described above can be appropriately selected and applied. The opening region of the light shielding film 13 is described with reference to FIGS. 7 and 8 in addition to FIG. It is possible that

  In addition to the configuration shown in FIGS. 11A, 11B, and 11C, the configuration shown in FIGS. 12A, 12B, and 12C is also possible as the configuration that gives the light scattering characteristics to the lower substrate 1 side. is there. Here, FIG. 12A is a partial plan view showing a configuration of a substrate having light scattering characteristics, FIG. 12B is a schematic cross-sectional view taken along line EE-EE ′ in FIG. 12A, and FIG. 12C is FIG. It is a schematic sectional drawing about line FF-FF 'in FIG.

  As shown in these drawings, the upper surface of the substrate 1 is directly roughened, and the reflective film 2 is formed on the rough surface 17. The rough surface 17 in the substrate 1 is made of glass as the substrate 1 and the surface thereof is etched non-uniformly with an aqueous solution containing hydrofluoric acid as a main component so as to have the following shape. Obtained by. That is, the surface of the substrate 1 is uneven so that the difference between the peaks and valleys is 0.05 μm to 2.5 μm, the pitch between the peaks and valleys is 1 μm to 50 μm, and the shape is random. Is etched.

  Even in such a configuration, the reflective film 2 reflects the rough surface 17 of the substrate 1 and reflects incident light from the upper substrate 101 side at a random angle, so only the lower substrate 1 side is reflected. Thus, it is possible to provide appropriate scattering characteristics. In such a configuration, the surface of the reflective film 2 reflects the rough surface of the rough surface 17, but is flat by the colored layer 4 and the protective film 6 formed so as to cover the surface of the reflective film 2. Therefore, the electrode 7 is formed on a flat surface without reflecting the rough surface.

  In FIG. 12A, FIG. 12B, and FIG. 12C, the other configurations are the same as those already described, and therefore, the same reference numerals are given and description thereof is omitted. In these figures, a portion where three colored layers 4 are laminated is used as the light-shielding film 13, but it is needless to say that a black resin material may be used as well. Furthermore, the protective films 3 and 6 and the adhesion improving layers 5 and 8 described above can be appropriately selected and applied. The opening region of the light shielding film 13 is described with reference to FIGS. 7 and 8 in addition to FIG. This also applies to the point that it can be used.

<Second Embodiment>
Next, a transflective liquid crystal device according to a second embodiment of the present invention will be described. In the reflection type liquid crystal device according to the first embodiment described above, a very bright display is possible if the intensity of the external light is sufficient. On the other hand, if the intensity of the external light is insufficient, the display is performed. Has the disadvantage of becoming difficult to see.

Therefore, the transflective liquid crystal device according to the second embodiment is provided with an opening for each pixel in the reflective film 2 so that light incident from the back side can pass therethrough and the intensity of external light is insufficient. If there is, the transmissive display by the light passing through the opening is performed, while if the intensity of the external light is sufficient, the reflective display by the light reflected from other than the opening is performed.

  FIG. 13 is a schematic cross-sectional view showing the configuration of the liquid crystal device according to the second embodiment. The liquid crystal device shown in this figure is different from the liquid crystal device according to the first embodiment shown in FIG. 1 in that a linear fluorescent tube 31 that emits white light and a conductive tube with one end face disposed along the fluorescent tube 31. A first point provided with an auxiliary light source including an optical plate 33, a second point where a retardation plate 23 and a polarizing plate 25 are provided in this order on the outer surface side of the substrate 1, and reflection for each opening region of the light shielding film 13. A portion where the opening portion (first opening portion) 14 is provided in the film 2 to transmit the light incident from below, and a portion where the colored layer 4 is laminated for three colors as the light-shielding film 13 Is in the fourth point where is used.

Other constitutions are similar to those already described are denoted with the same reference numerals and description thereof is omitted, also the fourth point also, since described in to, and their description Omitted. Therefore, here, the description will be focused on the first, second, and third points.

  First, the light guide plate 33 is a transparent body in which a rough surface for scattering is formed on the entire back surface (lower surface in the figure), or a transparent body such as an acrylic resin plate in which a printing layer for scattering is formed. . Thereby, when the light from the fluorescent tube 31 is incident on one end face of the light guide plate 33, the light guide plate 33 irradiates the upper surface of the figure with substantially uniform light. In addition, as an auxiliary light source, an LED (light emitting diode), an EL (electroluminescence), or the like can be used.

  Next, the polarizing plate 25 and the phase difference plate 23 provided on the outer surface of the substrate 1 are provided in order to make the light irradiated from the auxiliary light source have a predetermined polarization state.

  As shown in FIG. 14A, the opening 14 of the reflective film 2 is provided for each opening region 12 of the light shielding film 13, that is, for each region in which the colored layer 4 is provided for one color. Then, a reflective metal layer such as aluminum, silver, or chromium is formed by patterning so as to include the display region 9 and to remove a portion corresponding to the opening 14. Here, as shown in FIG. 13 or FIG. 14B, since the colored layer 4 is filled in the opening 14, the colored layer 4 enters from the back side (lower side in the figure), passes through the opening 14, and is observed. The light emitted to the side (upper side in the figure) is colored by the colored layer 4. In FIG. 14A, the planar shape of the opening 14 is rectangular, but it may be any shape.

  14A is a diagram showing the internal structure of the substrate 1 in FIG. 13, particularly the positional relationship between the opening 14 of the reflective film 2 and the opening region 12 of the light shielding film 13, and FIG. 14C is a schematic cross-sectional view taken along the line Y ′, and FIG. 14C is a schematic cross-sectional view taken along the line ZZ ′ in FIG. 14A. Since the opening region 12 of the light shielding film 13 has already been described, Then, it will be omitted.

  In such a second embodiment, if the intensity of external light is sufficient, the fluorescent tube 31 is turned off and a reflective display is performed. Here, in the reflective display, light reaches the reflective film 2 through a path of the polarizing plate 125, the retardation plate 123, the front scattering plate 121, the substrate 101, the electrode 110, the liquid crystal layer 58, the electrode 7, and the colored layer 4. Then, the light is reflected here, and the current path is traced in the reverse direction and emitted from the polarizing plate 125 to the observation side. At this time, the amount of light emitted from the polarizing plate 125 is set to a bright state, a dark state, and an intermediate brightness state according to the voltage applied to the liquid crystal layer 58 by the electrodes 7 and 110. A desired display can be achieved by controlling the voltage applied to the.

  On the other hand, if the intensity of the external light is insufficient, the fluorescent tube 31 is turned on and transmissive display is performed. Here, in the transmissive display, the light irradiated by the fluorescent tube 31 and the light guide plate 33 passes through the polarizing plate 25 and the retardation plate 23 to be in a predetermined polarization state, and the substrate 1, the opening 14, the electrode 7, The light is emitted from the polarizing plate 125 to the observation side through the liquid crystal layer 58 and the electrode 110. At this time, the amount of light emitted from the polarizing plate 125 is in a bright state, a dark state, and an intermediate brightness state according to the voltage applied to the liquid crystal layer 58 by the electrodes 7 and 110 as in the transmissive display. Therefore, desired display can be performed by controlling the voltage applied to the liquid crystal layer 58.

  According to this liquid crystal device, since the liquid crystal layer 58 is sandwiched between the electrodes 7 and 110 made of the same ITO, display quality and long-term reliability are not deteriorated. Further, since the light shielding film 13 and the colored layer 4 are formed on the reflective film 2, the reflective film 2 can be prevented from being exposed. For this reason, in the manufacturing process of the liquid crystal device, the reflection film 2 is not exposed to the chemical solution, the gas, the liquid crystal layer, and the like, so that damage to the reflection film 2 can be suppressed. Furthermore, since the colored layer 4 is formed so as to cover the light shielding film 13, not only the surface reflection at the light shielding film 13 is suppressed, but also the optical density required for the light shielding film 13 is small. For example, since light passes through the light shielding film twice in the reflective display, the substantial optical density of the light shielding film 13 may be small. In the transmissive display, the light is not defined by the light shielding film 13. In other words, the optical density of the light shielding film 13 hardly affects the transmissive display. For this reason, according to the present embodiment, it is possible to perform a bright and high-quality display in which a reduction in contrast ratio is suppressed in a transmissive display even in a transmissive display.

  In addition, in the conventional configuration in which the reflective film also serves as an electrode, if an opening is provided in the reflective film, a voltage is not applied to the liquid crystal layer in this portion, and thus a region where liquid crystal molecules are not driven normally (does not contribute to display) appears. It will end up. On the other hand, in the present embodiment, the reflective film 2 and the electrode 7 are independent, and the electrode 7 can be provided at the position of the opening 14. Will be driven. Therefore, in this sense as well, in this embodiment, a reduction in contrast ratio in transmissive display can be suppressed.

  By the way, about the structure of the board | substrate 1 in 2nd Embodiment, it is not restricted to what is shown by FIG.13, FIG.14 etc., A various aspect is applicable. Therefore, some of these aspects will be described.

  First, this aspect will be described with reference to FIGS. 15A, 15B, and 15C. Here, FIG. 15A is a partial plan view showing the configuration of the substrate on which up to the electrodes 7 are formed, and FIG. 15B is a schematic sectional view taken along line AA-AA ′ in FIG. 15A. FIG. 15C is a schematic cross-sectional view taken along line BB-BB ′ in FIG. 15A.

  As shown in these drawings, two openings 14 and 15 are provided for one pixel. Among these, as shown in FIG. 13, FIG. 14B, and FIG. 14C, the opening 14 is a portion in which the reflective film 2 does not exist and is filled with the colored layer 4, but the opening (second opening Part) 15, as shown in FIG. 15C, the colored layer 4 is not provided in the portion where the reflective film 2 exists, that is, the reflective film 2 is exposed at the stage of forming the colored layer 4. It is formed to do. Specifically, the opening 15 is a portion corresponding to the opening 15 when the photosensitive color resists of R (red), G (green), and B (blue) are sequentially formed by using the color sensitive material method. Further, the photosensitive color resist is not left.

  Here, the area of the opening 15 where the colored layer 4 is not provided is the area of the light-shielding film 13 excluding the opening 14 from the opening region 12 (that is, the area that substantially functions as one pixel in the reflective display). ) Is set as follows. That is, if the light transmission characteristic of the colored layer suitable for the transmissive display is FIG. 16A and the light transmission characteristic of the colored layer suitable for the reflective display is FIG. 16B, first, it passes through the opening 14. The colored layer 4 is formed so that the characteristic only by light becomes the characteristic shown in FIG. 16A, and secondly, the colored layer is reflected by the portion of the opening region 12 of the light shielding film 13 excluding the opening 14. The area of the opening 15 is set in accordance with each color so that the average light of the light colored by 4 and the light not reflected and colored by the opening 15 has the characteristics shown in FIG. 16B. It is desirable to do. Note that the characteristics of each color shown in FIGS. 16A and 16B are merely examples, and actually, the characteristics are appropriately changed according to the liquid crystal mode to be combined, the transmittance, and the color density.

  According to this aspect, since the color characteristics of light can be optimized in accordance with the reflective display and the transmissive display, it is possible to realize excellent color reproducibility in both displays. .

  In the second embodiment, the portion where the colored layers 4 are laminated for three colors is used as the light shielding film 13, but a black resin material is used as shown in FIGS. 17A, 17B and 17C. Of course, it may be done.

  In addition, as the substrate located on the back side in the second embodiment, each element of the substrate described in the first embodiment is appropriately selected with respect to the substrate shown in FIG. 14A, FIG. 15A, FIG. It is possible to apply. For example, the protective films 3 and 6 and the adhesion improving layers 5 and 8 may be appropriately selected and applied, or the reflective film 2 may be formed on the rough surface layer 16 in FIG. 11B or the rough surface 17 in FIG. 12B. The openings 14 and 15 may be provided.

<Electronic equipment>
Next, an electronic apparatus to which the liquid crystal device according to the first embodiment, the second embodiment, or the application example described above is applied will be described. As described above, these liquid crystal devices are suitable for portable devices that are used in various environments and require low power consumption.

First, FIG. 18A is a perspective view illustrating a configuration of a portable information device which is an example of an electronic device. As shown in this figure, the liquid crystal device 181 according to the embodiment is provided on the upper side of the portable information device main body, and the input unit 183 is provided on the lower side. In general, a touch panel is often provided on the front surface of the display unit of this type of portable information device.
A normal touch panel has a lot of surface reflections, so the display is difficult to see. For this reason, conventionally, a transmissive liquid crystal device is often used for a display unit even in a portable type. However, a transmissive liquid crystal device always uses an auxiliary light source and consumes a large amount of power. Life was short. On the other hand, the liquid crystal device according to the embodiment is suitable for a portable information device because the display is bright and vivid regardless of whether it is a reflective type or a transflective type.

  Next, FIG. 18B is a perspective view illustrating a configuration of a mobile phone which is an example of the electronic apparatus. As shown in this figure, the liquid crystal device 184 according to the embodiment is provided in the upper front part of the mobile phone body. Mobile phones are used in all environments, whether indoors or outdoors. Although it is often used in automobiles, it is very dark at night. For this reason, the display device 184 is mainly a reflective display with low power consumption, and a transflective liquid crystal device capable of performing transmissive display using auxiliary light as necessary, that is, according to the second embodiment. A liquid crystal device is desirable. The liquid crystal device 184 is brighter than the conventional liquid crystal device in both the reflective display and the transmissive display, and has a high contrast ratio and can display with high quality.

  18C is a perspective view illustrating a configuration of a watch which is an example of an electronic device. As shown in this figure, a display unit 186 according to the embodiment is provided in the center of the watch body. An important aspect in watch applications is luxury. The liquid crystal device 184 is not only bright and high in contrast, but also has little coloration because there is little change in characteristics due to the wavelength of light. Therefore, an extremely high-quality display can be obtained as compared with the conventional liquid crystal device.

1 is a schematic cross-sectional view illustrating a configuration of a reflective liquid crystal device according to a first embodiment of the present invention. It is a schematic sectional drawing which shows an example of the board | substrate located in the back side in the same embodiment. It is a schematic sectional drawing which shows another example of the board | substrate. It is a schematic sectional drawing which shows another example of the board | substrate. It is a schematic sectional drawing which shows another example of the board | substrate. It is a schematic sectional drawing which shows another example of the board | substrate. A is a top view which shows the positional relationship of the opening area | region of the light shielding film in the board | substrate located in the back surface in the same embodiment. FIG. 7B is a schematic cross-sectional view taken along line A-A ′ in FIG. 7A, showing a configuration in which a colored layer is formed. FIG. 7C is a schematic cross-sectional view taken along line A-A ′ in FIG. 7A, showing a configuration in which electrodes are formed. FIG. 4A is a partial plan view showing the positional relationship of the opening regions of the light shielding film on the substrate located on the back side in the same embodiment. FIG. 8B is a schematic cross-sectional view taken along line E-E ′ in FIG. 8A, showing a configuration in which electrodes are formed. FIG. 8C is a schematic cross-sectional view taken along line F-F ′ in FIG. FIG. 4A is a partial plan view showing the positional relationship of the opening regions of the light shielding film on the substrate located on the back side in the same embodiment. FIG. 9B is a schematic cross-sectional view taken along line L-L ′ in FIG. 9A and shows a configuration in which electrodes are formed. FIG. 9C is a schematic cross-sectional view taken along line M-M ′ in FIG. 9A, illustrating a configuration in which electrodes are formed. FIG. 4A is a partial plan view showing a configuration of another example of the substrate located on the back side in the embodiment. FIG. 10B is a schematic cross-sectional view taken along line W-W ′ in FIG. 10A and shows a configuration in which electrodes are formed. FIG. 10C is a schematic cross-sectional view taken along line X-X ′ in FIG. 10A, showing a configuration in which electrodes are formed. A is a partial top view which shows the structure of another example of the board | substrate located in the same embodiment in the back side. FIG. 11B is a schematic cross-sectional view taken along line CC-CC ′ in FIG. 11A and shows a configuration in which electrodes are formed. FIG. 11C is a schematic cross-sectional view taken along line DD-DD ′ in FIG. 11A and shows a configuration in which electrodes are formed. A is a partial top view which shows the structure of another example of the board | substrate located in the back side in the embodiment. FIG. 12B is a schematic cross-sectional view taken along line EE-EE ′ in FIG. 12A and shows a configuration in which electrodes are formed. FIG. 12C is a schematic sectional view taken along line FF-FF ′ in FIG. 12A and shows a configuration in which electrodes are formed. It is a schematic sectional drawing which shows the structure of the reflection type liquid crystal device which concerns on the 2nd Embodiment of this invention. FIG. 4A is a partial plan view showing the positional relationship of openings in a substrate located on the back side in the same embodiment. FIG. 14B is a schematic cross-sectional view taken along line Y-Y ′ in FIG. 14A and shows a configuration in which electrodes are formed. FIG. 14C is a schematic cross-sectional view taken along line Z-Z ′ in FIG. 14A and shows a configuration in which electrodes are formed. A is a partial top view which shows the structure applicable as a board | substrate located in the back side in the embodiment. FIG. 15B is a schematic sectional view taken along line AA-AA ′ in FIG. 15A. C is a schematic cross-sectional view taken along line BB-BB ′ in FIG. 15A. A is a figure which shows the characteristic of each color colored layer in a transmissive display. B is a figure which shows the characteristic of each color colored layer in reflection type display. FIG. 4A is a partial plan view showing a positional relationship of openings in an example of a substrate located on the back side in the embodiment. FIG. 17B is a schematic cross-sectional view taken along line N-N ′ in FIG. C is a schematic cross-sectional view taken along line O-O ′ in FIG. 17A. FIG. 2A is a perspective view illustrating a configuration of a portable information device to which a liquid crystal device according to an embodiment is applied. FIG. 7B is a perspective view illustrating a configuration of a mobile phone to which the liquid crystal device according to the embodiment is applied. C is a perspective view illustrating a configuration of a watch to which the liquid crystal device according to the embodiment is applied. A is a schematic plan view showing a configuration of a general passive matrix liquid crystal device. B is a plan view showing the alignment direction of the liquid crystal molecules adjacent to the substrate in the liquid crystal device and the alignment direction of the liquid crystal molecules in the bulk of the liquid crystal layer. C is a schematic cross-sectional view taken along line GG-GG ′ of FIG. 19A when no voltage is applied. FIG. 19D is a schematic cross-sectional view taken along line GG-GG ′ in FIG. 19A when a voltage is applied.

Claims (2)

A liquid crystal layer sandwiched between the first substrate and the second substrate, Ri Na has a plurality of pixel areas, the reflective display and the light incident from the observation side is reflected by the plurality of pixel areas A liquid crystal device that performs transmissive display in which light incident from the back side is transmitted through the plurality of pixel regions ,
A light shielding film having an opening region corresponding to the plurality of pixel regions;
The light shielding film overlaps with the light shielding film so as to be on the observation side with respect to the reflective film over the entire circumference of the opening area of the light shielding film, and within the opening area of the light shielding film, within the opening area of the light shielding film. said reflective film provided on a part,
In the opening area of the light shielding film, the light shielding film is provided so as to overlap a part of the area where the reflective film is provided and the area where the reflective film is not provided , and so as to overlap the entire light shielding film. A colored layer,
Comprising
The opening area of the light shielding film, the light transmission characteristics showing transmittance relationship to the wavelength of light to be colored by the coloring layer located in a region where the reflective film is not provided in the transmissive display, reflective display In the wavelength of the average light of the light colored by the colored layer located in the region where the reflective film is provided and the light which is not colored by the region where the colored layer is not provided in the region where the reflective film is provided It is different from the light transmission characteristics indicating the relationship of transmittance,
In the reflective display, the average light is the sum of the light colored by the colored layer located in the region where the reflective film is provided and the light not colored by the region where the colored layer is not formed in the region where the reflective film is provided. The minimum transmittance in the light transmission characteristics is higher than the minimum transmittance in the light transmission characteristics of light colored by the colored layer located in a region where the reflective film is not provided in a transmissive display. Liquid crystal device. The thickness of the colored layer located in a region where the reflective film is not provided is formed to be thicker than the thickness of the colored layer located in a region where the reflective film is provided. 2. A liquid crystal device according to 1 .

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