JP2009025509A - Liquid crystal display and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display of excellent display quality, capable of enhancing flatness of an electrode on a reflecting layer, by forming a flattened layer on the reflecting layer having an irregular shape on a surface, and capable of uniformizing an electric field generated between the electrode on the flattened layer and the other electrode. <P>SOLUTION: This liquid crystal display 100 is provided with the first substrate 10, the second substrate 20, and a liquid crystal layer positioned between the first substrate 10 and the second substrate 20, and the first substrate 10 is provided with the reflecting layer 14 arranged in a prescribed area and having the irregular shape on the surface, the flattened layer 16 formed to cover the reflecting layer 14, and the common electrode 17 and the pixel electrode 19 provided on the flattened layer 16. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device and a method for manufacturing the same.

  In a transflective liquid crystal display device having a transmissive display area and a reflective display area in one pixel area and having both a transmissive type and a reflective type, a lower part of an upper substrate and a lower substrate sandwiching a liquid crystal layer is used. A reflective layer is provided in the reflective display region on the liquid crystal layer side of the substrate. The reflective layer is formed of a highly reflective metal film such as aluminum on the base resin layer having an uneven shape for scattering external light, and the reflective layer has a surface shape reflecting the uneven shape of the base resin layer. Have.

  In such a transflective liquid crystal display device, a configuration in which a retardation layer is disposed on a reflective layer has been proposed (for example, Patent Document 1). Further, a configuration has been proposed in which an IPS (In-Plane Switching) type electrode is disposed on a reflective layer (for example, Patent Document 2). In any configuration, since the retardation layer is disposed only in the reflective display region in the liquid crystal cell, the display quality of the transmissive display region is lowered as compared with the configuration in which the retardation layer is disposed on both sides outside the liquid crystal cell. In addition, the entire liquid crystal display device can be made thin.

JP 2004-38205 A JP 2005-338256 A

  When an electric field parallel to the surface direction of the substrate is generated as in the IPS method, it is desirable that the electrode be flat with respect to the substrate surface. However, in the configuration in which the electrode is disposed on the reflective layer, the surface on which the electrode is formed has an uneven shape, and therefore the uneven shape is reflected on the electrode. Therefore, when an electric field is generated between such electrodes, the direction of the electric field may be disturbed in the reflective display region.

  In addition, in the configuration in which the retardation layer is disposed on the reflective layer, the retardation layer is disposed on the surface having the concavo-convex shape, so that the thickness of the retardation layer varies and the optical compensation characteristics of the retardation layer are reduced. It may be damaged. As described above, when the electric field generated between the electrodes is disturbed or the thickness of the retardation layer varies, the viewing angle characteristic in the reflective display region of the liquid crystal display device is deteriorated.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A liquid crystal display device according to this application example includes a first substrate, a second substrate, and a liquid crystal layer positioned between the first substrate and the second substrate. In the liquid crystal display device, the first substrate includes a reflective layer disposed in a predetermined region and having a concavo-convex shape on a surface thereof, a planarization layer formed so as to cover the reflective layer, and the planarization layer And at least one electrode provided thereon.

  According to this configuration, since the uneven shape on the surface of the reflective layer is flattened by the flattening layer, the flatness of the electrode provided on the flattening layer is improved. For this reason, the layer thickness of the liquid crystal layer arranged facing the electrode can be made more uniform. Thereby, a liquid crystal display device having excellent display quality can be provided.

  Application Example 2 In the liquid crystal display device according to the application example described above, a common electrode disposed on the planarization layer so that an electric field is generated in a direction parallel to the first substrate surface when a voltage is applied. And a pixel electrode may be provided.

  According to this configuration, since the uneven shape on the surface of the reflective layer is flattened by the flattening layer, the flatness between the common electrode and the pixel electrode provided on the flattening layer is improved. Therefore, when a voltage is applied between the common electrode and the pixel electrode, an electric field in a direction parallel to the first substrate surface is more uniformly generated over the range where the common electrode and the pixel electrode are disposed. . Thereby, a liquid crystal display device having excellent display quality can be provided.

  Application Example 3 In the liquid crystal display device according to the application example described above, a first electrode is provided on the planarization layer, and the second substrate is provided so as to face the first electrode. The second electrode may be provided.

  According to this configuration, since the uneven shape on the surface of the reflective layer is flattened by the flattening layer, the flatness of the first electrode provided on the flattening layer is improved. Therefore, when a voltage is applied between the second electrode provided on the second substrate facing the first electrode, the first electrode and the second electrode are opposed to each other. An electric field in a direction perpendicular to the first substrate surface is generated more uniformly. Thereby, a liquid crystal display device having excellent display quality can be provided.

  Application Example 4 A liquid crystal display device according to this application example includes a first substrate, a second substrate, and a liquid crystal layer positioned between the first substrate and the second substrate. In the liquid crystal display device, the first substrate includes a reflective layer having a concavo-convex shape on a surface, a planarization layer formed so as to cover the reflective layer, and a position provided on the planarization layer. And a phase difference layer.

  According to this configuration, since the uneven shape on the surface of the reflective layer is flattened by the flattening layer, the flatness of the retardation layer provided on the flattening layer is improved. For this reason, since the layer thickness of the retardation layer can be made more uniform, the optical compensation characteristics of the retardation layer are improved. Further, the layer thickness of the liquid crystal layer disposed to face the retardation layer becomes more uniform. Thereby, a liquid crystal display device having excellent display quality can be provided.

  Application Example 5 In the liquid crystal display device according to the application example, the first substrate further includes a base layer, and the base layer has the uneven shape in the predetermined region, The reflective layer may be formed so as to cover the predetermined region on the base layer.

  According to this configuration, the underlayer has an uneven shape on the surface in a predetermined region. Since the reflective layer is formed so as to cover a predetermined region on the base layer, the surface of the reflective layer can be shaped to reflect the uneven shape of the base layer.

  Application Example 6 In the liquid crystal display device according to the application example described above, a transmissive display region and a reflective display region as the predetermined region are included in one pixel region, and the reflective layer includes the reflective layer It may be arranged in the display area.

  According to this configuration, the thickness of the liquid crystal layer can be made more uniform in the reflective display region. Further, when an electrode is provided on the reflective layer, the generated electric field can be made more uniform, and when a retardation layer is provided on the reflective layer, the optical compensation characteristics of the retardation layer are improved. Thereby, a transflective liquid crystal display device having excellent display quality can be provided.

  Application Example 7 A method for manufacturing a liquid crystal display device according to this application example includes a first substrate, a second substrate, and a liquid crystal layer positioned between the first substrate and the second substrate. And a reflective layer forming step of forming a reflective layer having a concavo-convex shape on a surface thereof in a predetermined region on the base material of the first substrate, and covering the reflective layer A photosensitive material arranging step of arranging a transparent photosensitive material as described above, and a flattening layer forming step of flattening the surface of the photosensitive material by exposing and developing the arranged photosensitive material. In the planarization layer forming step, the amount of the photosensitive material removed by the development is the largest in the portion corresponding to the top of the uneven shape, and from the portion corresponding to the top to the bottom of the uneven shape. Performing the exposure so as to decrease toward the corresponding part. And butterflies.

  According to this structure, the photosensitive material arrange | positioned on the reflective layer at the photosensitive material arrangement | positioning process has the surface shape which reflected the uneven | corrugated shape of the reflective layer. On the other hand, the amount of the photosensitive material removed by development in the planarization layer forming step is the largest at the top of the uneven shape of the photosensitive material and decreases from the top of the uneven shape toward the bottom. Thereby, since the surface of the photosensitive material is leveled to substantially the same height, a planarization layer can be formed. If an electrode is formed on the planarization layer, the generated electric field can be made more uniform, and if a retardation layer is formed on the planarization layer, the optical compensation characteristics of the retardation layer can be improved. Accordingly, a liquid crystal display device having excellent display quality can be provided. In addition, if electrodes are formed on the planarization layer, the risk of cracks and poor adhesion that tend to occur when a fine electrode pattern is formed on an uneven surface can be avoided, and a liquid crystal display device can be manufactured with a high yield. it can.

  Application Example 8 In the method of manufacturing a liquid crystal display device according to the application example, the photosensitive material is a positive photosensitive resin, and in the planarization layer forming step, the positive photosensitive resin is used during the exposure. The intensity of the light applied to the top may be changed so as to be strongest at a portion corresponding to the vertex and weaken from a portion corresponding to the vertex toward a portion corresponding to the bottom.

  According to this configuration, the positive photosensitive resin has a higher bond separation ratio in a portion where the light irradiated at the time of exposure is stronger, and as a result, the amount removed at the time of development increases. Therefore, the separation of the bonding of the positive photosensitive resin is the highest at the apex portion of the uneven shape and decreases from the apex portion of the uneven shape toward the bottom. Thereby, the amount of the photosensitive material removed at the time of development can be maximized at the peak portion of the concavo-convex shape and continuously decreased from the peak portion of the concavo-convex shape toward the bottom portion.

  Application Example 9 In the method for manufacturing a liquid crystal display device according to the application example, in the planarization layer forming step, the light is applied to the positive photosensitive resin through a mask during the exposure, and the mask includes: The light transmittance may be highest at a portion corresponding to the vertex, and the light transmittance may be decreased from a portion corresponding to the vertex toward a portion corresponding to the bottom portion.

  According to this configuration, even if light is irradiated from the same light source at the time of exposure, the intensity of the light transmitted through the mask to the photosensitive material is high and low in the light transmittance in the mask. The intensity of light applied to the photosensitive material increases as the light transmittance increases. As a result, the intensity of light applied to the photosensitive material can be made strongest at the apex portion of the uneven shape and weakened from the apex portion of the uneven shape toward the bottom portion.

  [Application Example 10] A method of manufacturing a liquid crystal display device according to the application example described above, including a base layer forming step of forming a base layer on the base material before the reflective layer forming step, and forming the base layer In the step, the uneven shape is formed on the surface of the base layer in the predetermined region, and in the reflective layer forming step, the material of the reflective layer may be disposed so as to cover the predetermined region of the base layer. Good.

  According to this configuration, the base layer is formed before the reflective layer forming step, and in the base layer forming step, an uneven shape is formed on the surface of a predetermined region of the base layer. In the reflective layer forming step, the reflective layer is formed so as to cover a predetermined region on the base layer, so that the surface of the reflective layer can be shaped to reflect the uneven shape of the base layer.

  Application Example 11 A method for manufacturing a liquid crystal display device according to the application example described above, wherein a transmission display area and a reflection display area as the predetermined area are included in one pixel area, and the reflection layer formation is performed. In the step, the reflective layer may be formed in the reflective display region.

  According to this configuration, the thickness of the liquid crystal layer can be made more uniform in the reflective display region. Further, when an electrode is provided on the reflective layer, the generated electric field can be made more uniform, and when a retardation layer is provided on the reflective layer, the optical compensation characteristics of the retardation layer are improved. Thereby, a transflective liquid crystal display device having excellent display quality can be provided.

  Hereinafter, the present embodiment will be described with reference to the drawings. In each of the drawings to be referred to, the layer thicknesses and dimensional ratios of the constituent elements are appropriately changed in order to easily show the configuration. In each drawing to be referred to, elements, wiring, connection portions, and the like are omitted.

(First embodiment)
<Liquid crystal display device>
First, the configuration of the liquid crystal display device according to the first embodiment will be described with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a schematic configuration of the liquid crystal display device according to the first embodiment. Specifically, FIG. 3 is a cross-sectional view taken along the line AA ′ in FIG. FIG. 2 is a plan view showing a pixel region of the liquid crystal display device according to the first embodiment.

  As shown in FIG. 1, the liquid crystal display device 100 according to the present embodiment is an FFS (Fringe-Field Switching) type transflective liquid crystal display device having a transmissive display region T and a reflective display region R. The liquid crystal display device 100 includes a first substrate 10, a second substrate 20, and a liquid crystal layer 30. The first substrate 10 and the second substrate 20 are arranged to face each other, and the second substrate 20 is located on the observation side of the liquid crystal display device 100.

  The first substrate 10 includes a first base 11 as a base, a first insulating layer 13 as a base layer, a reflective layer 14, a planarization layer 16, a common electrode 17, and a second An insulating layer 18 and a pixel electrode 19 are provided. The first base material 11 is made of a transparent material, for example, glass.

  The first insulating layer 13 is formed so as to cover the liquid crystal layer 30 side of the first base material 11. In the reflective display region R of the first insulating layer 13, an uneven shape for scattering external light is formed. The height of the top of the first insulating layer 13 with respect to the bottom of the concavo-convex shape is, for example, about 1 μm. Moreover, the space | interval between the adjacent vertexes of uneven | corrugated shape is 5-15 micrometers, for example. The first insulating layer 13 is made of a photosensitive material, for example, a positive photosensitive resin.

  The reflective layer 14 is formed in a thin film shape so as to cover the uneven shape of the first insulating layer 13 only in the reflective display region R on the first insulating layer 13. The thickness of the reflective layer 14 is, for example, about 100 nm. Therefore, the surface shape of the reflective layer 14 is an uneven shape reflecting the uneven shape of the first insulating layer 13. The reflective layer 14 is made of a highly reflective metal film, for example, aluminum. The material of the reflective layer 14 may be APC (silver-palladium-copper alloy).

  The planarizing layer 16 is formed in the reflective display region R so as to cover the reflective layer 14. The planarization layer 16 has a substantially flat surface. Since the surface of the reflective layer 14 has an uneven shape, the planarizing layer 16 has a thick portion corresponding to the concave portion of the reflective layer 14 and a thin portion corresponding to the convex portion of the reflective layer 14. The thickness of the planarization layer 16 is, for example, about 2 μm at the thickest portion, and is about 1 μm at the thinnest portion. The planarizing layer 16 is made of a transparent photosensitive material, for example, a positive photosensitive resin. As an example of the transparent positive photosensitive resin, PC405G manufactured by JSR Corporation can be used.

  The common electrode 17 is formed over the reflective display region R and the transmissive display region T. In the reflective display region R, the common electrode 17 is formed on the planarizing layer 16, and in the transmissive display region T, the first insulating layer 13 is formed. Formed on top. The common electrode 17 is made of, for example, ITO (Indium Tin Oxide). A second insulating layer 18 is formed on the common electrode 17 so as to cover the upper surface thereof. Further, a pixel electrode 19 having a plurality of slit-shaped openings 19 a is formed on the second insulating layer 18. The pixel electrode 19 is made of, for example, ITO.

  As shown in FIG. 2, each of the plurality of pixel electrodes 19 is disposed across the reflective display region R and the transmissive display region T. The plurality of pixel electrodes 19 are arranged in a matrix. The plurality of pixel electrodes 19 are adjacent to each other so that the reflective display regions R or the transmissive display regions T face each other in the direction along the X axis, and the reflective display region R and the transmissive display region in the direction along the Y axis. T are adjacent to each other so as to face each other.

  Each of the plurality of pixel electrodes 19 corresponds to one of three colors of red, green, and blue of a color filter layer 22 (see FIG. 1) described later. Three color sub-pixels 24R (Red), 24G (Green), and 24B (Blue) are configured by combining these three colors and the corresponding three pixel electrodes 19, respectively. One subpixel 24R, 24G, and 24B constitutes one pixel 25. Accordingly, one pixel 25 has a reflective display region R and a transmissive display region T.

  Returning to FIG. 1, the first polarizing plate 36 is disposed on the opposite side of the first substrate 10 from the liquid crystal layer 30. Although not shown, the first substrate 10 is provided with elements for driving the liquid crystal layer 30, wiring patterns, connection portions, and the like.

  The second substrate 20 includes a second base material 21, a color filter layer 22, and a protective layer 23. The 2nd base material 21 consists of a transparent material, for example, consists of glass. The color filter layer 22 and the protective layer 23 are sequentially laminated on the liquid crystal layer 30 side of the second base material 21. The color filter layer 22 includes, for example, three color elements of Red, Green, and Blue. A second polarizing plate 38 is disposed on the side of the second substrate 20 opposite to the liquid crystal layer 30, that is, on the observation side.

  The retardation layer 40 is located on the liquid crystal layer 30 side on the second substrate 20 and is disposed so as to overlap the reflective display region R. The retardation layer 40 is made of a material having birefringence. The phase difference layer 40 gives a predetermined phase difference to the wavelength of incident visible light. In the present embodiment, the phase difference layer 40 gives a phase difference of ½ wavelength to the incident visible light. An alignment film 41 for defining the slow axis direction of the retardation layer 40 is formed between the retardation layer 40 and the second substrate 20.

  The liquid crystal layer 30 is located between the first substrate 10 and the second substrate 20. A first alignment film 32 is formed on the side of the first substrate 10 in contact with the liquid crystal layer 30 so as to cover the second insulating layer 18 and the pixel electrode 19. A second alignment film 34 is formed on the side of the second substrate 20 in contact with the liquid crystal layer 30 so as to cover the protective layer 23 and the retardation layer 40. The alignment direction of the liquid crystal layer 30 is regulated by the alignment treatment applied to the first alignment film 32 and the second alignment film 34, and the liquid crystal layer 30 is homogeneously aligned.

  In this embodiment, although not shown, the slow axis of the retardation layer 40 is shifted by 22.5 ° clockwise relative to the transmission axis of the second polarizing plate 38, and the alignment direction of the liquid crystal layer 30 is the second. The polarizing plate 38 is shifted by 90 ° clockwise with respect to the transmission axis. The transmission axis of the first polarizing plate 36 is orthogonal to the transmission axis of the second polarizing plate 38.

  In such a transflective liquid crystal display device 100, the external light that reaches the reflective layer 14 when performing dark display in the reflective display region R must be substantially circularly polarized in all visible wavelength regions due to optical design. There is. This is because if the external light reaching the reflective layer 14 is elliptically polarized, the dark display will be colored, making it difficult to obtain a high-contrast reflective display.

  In the present embodiment, the retardation layer 40 is selectively disposed in the reflective display region R so that the thickness of the liquid crystal layer 30 in the reflective display region R is thinner than the thickness of the liquid crystal layer 30 in the transmissive display region T. It is configured. Specifically, the layer thickness in the reflective display region R of the liquid crystal layer 30 is approximately ½ of the layer thickness in the transmissive display region T. As a result, the liquid crystal layer 30 gives a phase difference of ¼ wavelength in the reflective display region R to the wavelength of incident visible light, and a phase difference of ½ wavelength in the transmissive display region T. Is granted. As a result, the second polarizing plate 38, the retardation layer 40, and the liquid crystal layer 30 in the reflective display region R can create broadband circularly polarized light, and external light reaching the reflective layer 14 is circular at all visible wavelengths. It is close to polarized light.

<Manufacturing method>
Next, a manufacturing method of the liquid crystal display device according to the first embodiment will be described with reference to the drawings. FIG. 3 is a flowchart showing a manufacturing method of the liquid crystal display device. 4 and 5 are cross-sectional views illustrating a method for manufacturing a liquid crystal display device. 6 and 7 are diagrams for explaining a mask used for manufacturing a liquid crystal display device. FIG. 8 is a graph showing the transmittance distribution of the mask.

  FIG. 3 shows a step of forming a planarization layer included in the liquid crystal display device according to this embodiment. As shown in FIG. 3, the planarization layer forming method according to the present embodiment includes a first insulating layer forming step (step S <b> 10) for forming the first insulating layer 13 and a reflective layer for forming the reflective layer 14. A forming process (step S20), a photosensitive material arranging process (step S30) for arranging a photosensitive material, and a planarizing layer forming process (step S40) in which the photosensitive material is exposed and developed to be flattened. I have.

<1. First insulating layer forming step>
In step S <b> 10 of FIG. 3, the first insulating layer 13 is formed on the first base material 11. First, as shown in FIG. 4, the material of the first insulating layer 13 is disposed on the first base material 11 by, for example, a spin coating method. Thereby, the first insulating material layer 12 is formed. Next, an uneven shape is formed in the reflective display region R of the arranged first insulating material layer 12. In the method for forming the concavo-convex shape, after the first insulating material layer 12 is exposed through a mask, development and baking are performed.

  FIG. 6 shows an example of a mask used during exposure. In the present embodiment, the mask 50 includes a plurality of light shielding parts 51 and a transmission part 52. The plurality of light shielding portions 51 are randomly arranged in the mask 50. The shape of the light shielding part 51 is, for example, a circle having a radius r. As shown in FIG. 4, the first insulating material layer 12 is irradiated with light through a mask 50. At this time, light is transmitted only through the transmission part 52 of the mask 50, and the part corresponding to the transmission part 52 of the first insulating material layer 12 is exposed.

  Next, the first insulating material layer 12 is developed, and the exposed portion is removed by exposure. Next, the first insulating material layer 12 is baked and cured at 220 ° C., for example. By this baking, the corners of the convex portions formed on the first insulating material layer 12 during development become a gentle curved surface. By the exposure, development, and baking described above, the removed portion 12a of the first insulating material layer 12 is removed, and the first insulating layer 13 is formed.

<2. Reflective layer forming step>
In step S <b> 20 of FIG. 3, the reflective layer 14 is formed in the reflective display region R on the first insulating layer 13. The reflective layer 14 is formed in a thin film shape so as to cover the uneven shape on the upper surface of the first insulating layer 13 by applying, for example, a sputtering method. Thereby, the surface shape of the reflective layer 14 becomes an uneven shape reflecting the uneven shape of the first insulating layer 13. A portion where the reflective layer is unnecessary, for example, a transmissive portion may be removed by photolithography after the reflective layer is formed.

<3. Photosensitive material placement process>
In step S30 of FIG. 3, a transparent photosensitive material that is the material of the planarization layer 16 is disposed so as to cover the reflective layer 14. In the present embodiment, a case where a positive photosensitive resin is used as the photosensitive material will be described as an example. First, as shown in FIG. 5, a positive photosensitive resin is disposed on the reflective layer 14 by, for example, a spin coating method to form a positive photosensitive resin layer 15. The layer thickness of the positive photosensitive resin layer 15 is, for example, about 2 to 3 μm. Thereby, the surface shape of the positive photosensitive resin layer 15 becomes an uneven shape substantially reflecting the uneven shape of the reflective layer 14.

<4. Planarization layer forming step>
In step S <b> 40 of FIG. 3, the planarizing layer 16 is formed by performing exposure and development on the positive photosensitive resin layer 15. First, the positive photosensitive resin layer 15 is exposed through a mask. FIG. 7 shows an example of a mask used during exposure. The mask 54 has a plurality of transmission parts 55 and light shielding parts 56. The plurality of transmission portions 55 are arranged corresponding to the positions of the convex portions of the reflective layer 14. Here, the mask 54 is a so-called halftone mask having regions in which the light transmittance is different in multiple gradations, and the light transmittance in the transmission portion 55 is different in multiple gradations. The transmissive part 55 has the highest light transmittance at a position corresponding to the top of the convex portion of the reflective layer 14, and the light transmittance continuously decreases from the part corresponding to the top to the part corresponding to the bottom. It is formed to become.

  In the present embodiment, since the concavo-convex shape of the reflective layer 14 reflects the concavo-convex shape of the first insulating layer 13, the transmissive portion 55 is the light shielding portion of the mask 50 used for forming the first insulating layer 13. It arrange | positions corresponding to the position of 51 (refer FIG. 6). The transmission part 55 has a circular shape having substantially the same radius r as that of the light shielding part 51, and the center 55 a thereof corresponds to the vertex of the convex part of the first insulating layer 13, that is, the vertex of the convex part of the reflective layer 14. As shown in FIG. 8, the light transmittance of the transmissive part 55 is continuously reduced from the center 55a to the outer peripheral part 55b, that is, from the position corresponding to the apex of the convex part of the reflective layer 14 toward the position corresponding to the bottom part. It has become. In addition, the light transmittance of the transmission part 55 may be gradually reduced from the center 55a toward the outer peripheral part 55b.

  As shown in FIG. 5, the positive photosensitive resin layer 15 is irradiated with light through a mask 54. At this time, the distance between the mask 54 and the positive photosensitive resin layer 15 is, for example, 60 to 80 μm, and the exposure amount is, for example, 100 to 150 mJ with light having a wavelength centered at 365 nm. The arrows in FIG. 5 schematically indicate the light that passes through the mask 54 and is applied to the positive photosensitive resin layer 15. The intensity of light transmitted through the mask 54 is the strongest at the center 55a of the transmission part 55 and continuously decreases from the center 55a toward the outer peripheral part 55b. Therefore, the light irradiated to the positive photosensitive resin layer 15 is the strongest at the position corresponding to the top of the convex portion of the reflective layer 14, and corresponds to the bottom from the position corresponding to the top of the convex portion of the reflective layer 14. It becomes weaker continuously toward the position.

  Next, the exposed positive photosensitive resin layer 15 is developed. In the positive photosensitive resin, the amount of light that is irradiated during exposure increases as the amount of light irradiated during exposure increases. Therefore, the amount of removal of the positive photosensitive resin layer 15 is greatest at a position corresponding to the top of the convex portion of the reflective layer 14 and corresponds to the bottom from the position corresponding to the top of the convex portion of the reflective layer 14. Less towards position. Since the positive photosensitive resin layer 15 has a surface shape that substantially reflects the uneven shape of the reflective layer 14, the amount removed during development of the positive photosensitive resin layer 15 is the peak of the convex portion. Becomes the most, and decreases continuously from the apex to the bottom. Thereby, the convex part 15a of the surface of the positive photosensitive resin layer 15 is removed, and the surface is leveled.

  Next, the positive photosensitive resin layer 15 is baked and cured at 220 ° C., for example. As described above, the planarization layer 16 is formed.

  According to the first embodiment, the following effects can be obtained.

  (1) In the liquid crystal display device 100, the uneven shape on the surface of the reflective layer 14 is flattened by the flattening layer 16, so that the flatness between the common electrode 17 and the pixel electrode 19 provided on the flattening layer 16 is high. improves. For this reason, the layer thickness in the reflective display region R of the liquid crystal layer 30 disposed to face the common electrode 17 and the pixel electrode 19 can be made more uniform. Further, when a voltage is applied between the common electrode 17 and the pixel electrode 19, an electric field in a direction parallel to the surface of the first substrate 10 is generated over a range where the common electrode 17 and the pixel electrode 19 are arranged. It occurs more uniformly. Thereby, the liquid crystal display device 100 having excellent display quality can be provided.

  (2) In the manufacturing method of the liquid crystal display device 100, the common electrode 17 and the pixel electrode 19 are formed on the planarizing layer 16, and therefore, this occurs when a fine electrode pattern is formed on a surface having an uneven shape. The risk of easy cracks and poor adhesion can be avoided, and the liquid crystal display device 100 can be manufactured with a high yield.

(Second Embodiment)
Next, the configuration of the liquid crystal display device according to the second embodiment will be described with reference to the drawings. In addition, about the component which is common in 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted. FIG. 9 is a cross-sectional view illustrating a schematic configuration of the liquid crystal display device according to the second embodiment.

  The liquid crystal display device 200 according to the second embodiment has an ECB (Electrically Controlled Birefringence) type electrode configuration with respect to the liquid crystal display device 100 according to the first embodiment, and in the liquid crystal cell. The difference is that a pair of retardation plates are arranged outside the liquid crystal cell instead of the retardation layer.

  As shown in FIG. 9, the liquid crystal display device 200 includes a first substrate 60, a second substrate 70, and a liquid crystal layer 31.

  The first substrate 60 includes the first base material 11, the first insulating layer 13, the reflective layer 14, the planarization layer 16, and the first electrode 62. The thickness of the first insulating layer 13 in the transmissive display region T is adjusted to be substantially the same as the total thickness of the first insulating layer 13, the reflective layer 14, and the planarizing layer 16 in the reflective display region R. ing. Therefore, the upper surface of the planarization layer 16 in the reflective display region R and the upper surface of the first insulating layer 13 in the transmissive display region T constitute a surface having almost no step. The first electrode 62 is provided on the planarization layer 16 and the first insulating layer 13. The first alignment film 32 is formed so as to cover the first electrode 62.

  The second substrate 70 includes the second base material 21, the color filter layer 22, the protective layer 23, and the second electrode 72. The layer thickness of the protective layer 23 in the reflective display region R is larger than the layer thickness in the transmissive display region T. The second electrode 72 is provided on the protective layer 23 so as to face the first electrode 62 across the reflective display region R and the transmissive display region T. The second alignment film 34 is formed so as to cover the second electrode 72.

  A first retardation plate 42 is disposed between the first substrate 60 and the first polarizing plate 36. A second retardation plate 44 is disposed between the second substrate 70 and the second polarizing plate 38. Each of the first phase difference plate 42 and the second phase difference plate 44 gives a phase difference of 1/4 wavelength to the wavelength of incident visible light. The slow axis of the first retardation plate 42 is shifted by 45 ° with respect to the transmission axis of the first polarizing plate 36, and the slow axis of the second retardation plate 44 is the second polarizing plate 38. 45 ° with respect to the transmission axis. The transmission axis of the first polarizing plate 36 and the transmission axis of the second polarizing plate 38 are orthogonal to each other, and the slow axis of the first retardation plate 42 and the slow phase of the second retardation plate 44 are used. It is orthogonal to the axis.

  In the present embodiment, the layer thickness of the protective layer 23 in the reflective display region R is made larger than the layer thickness in the transmissive display region T, so that the liquid crystal layer 31 in the reflective display region R has a liquid crystal layer in the transmissive display region T. It is configured to be thinner than the layer thickness of 31. Specifically, the layer thickness in the reflective display region R of the liquid crystal layer 31 is approximately ½ of the layer thickness in the transmissive display region T, and the liquid crystal layer 31 has a wavelength of incident visible light. A phase difference of ¼ wavelength is applied in the reflective display region R, and a phase difference of ½ wavelength is applied in the transmissive display region T. Accordingly, the second polarizing plate 38, the second retardation plate 44, and the liquid crystal layer 31 in the reflective display region R can create broadband circularly polarized light, and all the external light reaching the reflective layer 14 is visible. It is close to circularly polarized light at the wavelength.

  According to the second embodiment, the following effects can be obtained.

  (1) In the liquid crystal display device 200, since the uneven shape on the surface of the reflective layer 14 is flattened by the flattening layer 16, the flatness of the first electrode provided on the flattening layer 16 is improved. For this reason, when a voltage is applied between the second electrode 72 of the second substrate 20 facing the first electrode 62, the first electrode 62 and the second electrode 72 are in a range facing each other. The electric field in the direction perpendicular to the surface of the first substrate 10 is more uniformly generated. In addition, since the flatness of the first electrode 62 is improved, the layer thickness of the liquid crystal layer 31 in the reflective display region R can be made more uniform. Thereby, the liquid crystal display device 200 having excellent display quality can be provided.

(Third embodiment)
Next, the configuration of the liquid crystal display device according to the third embodiment will be described with reference to the drawings. In addition, about the component which is common in 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted. FIG. 10 is a cross-sectional view illustrating a schematic configuration of the liquid crystal display device according to the third embodiment.

  The liquid crystal display device 300 according to the third embodiment has an FFS (Fringe-Field Switching) type electrode configuration, like the liquid crystal display device 100 according to the first embodiment. However, the point that the retardation layer is disposed on the planarization layer of the first substrate, the point that the second substrate includes the common electrode and the pixel electrode, and the layer thickness of the liquid crystal layer are the reflective display region. And the same in the transmissive display area.

  As shown in FIG. 10, the liquid crystal display device 300 includes a first substrate 80, a second substrate 90, and a liquid crystal layer 33. The first substrate 80 includes a first base material 11, a first insulating layer 13, a reflective layer 14, and a planarizing layer 16.

  The retardation layer 46 is located on the liquid crystal layer 33 side on the first substrate 80 and is disposed so as to overlap the reflective display region R. An alignment film 45 for defining the slow axis direction of the retardation layer 46 is formed between the retardation layer 46 and the first substrate 80. In the present embodiment, the slow axis of the retardation layer 46 is shifted by 90 ° in the clockwise direction with respect to the transmission axis of the second polarizing plate 38. Further, the phase difference layer 46 gives a phase difference of ¼ wavelength to the wavelength of incident visible light.

  The thickness of the first insulating layer 13 in the transmissive display region T is the total thickness of the first insulating layer 13, the reflective layer 14, the planarizing layer 16, the alignment film 45, and the retardation layer 46 in the reflective display region R. Is adjusted to be almost the same. Therefore, the upper surface of the retardation layer 46 in the reflective display region R and the upper surface of the first insulating layer 13 in the transmissive display region T constitute a surface having almost no step. The first alignment film 32 is provided so as to cover the retardation layer 46 and the first insulating layer 13.

  The second substrate 90 includes the second base material 21, the color filter layer 22, the protective layer 23, the common electrode 17, the second insulating layer 18, and the pixel electrode 19. The common electrode 17, the second insulating layer 18, and the pixel electrode 19 are sequentially stacked on the protective layer 23. On the liquid crystal layer 33 side of the second substrate 90, the reflective display region R and the transmissive display region T form a surface having almost no step. The second alignment film 34 is formed so as to cover the second insulating layer 18 and the pixel electrode 19.

  In the present embodiment, the liquid crystal layer 33 has substantially the same layer thickness in the reflective display region R and the transmissive display region T. However, in the liquid crystal layer 33, the reflective display region R and the transmissive display region T have different directions for regulating the alignment of the liquid crystal. Specifically, the orientation direction of the liquid crystal layer 33 in the reflective display region R is shifted by 22.5 ° clockwise with respect to the transmission axis of the second polarizing plate 38, and the second polarizing plate 38 is applied when a voltage is applied. The same direction as the transmission axis. The alignment direction of the liquid crystal layer 33 in the transmissive display region T is the same as the polarization axis of the second polarizing plate 38, and is 45 ° clockwise with respect to the polarization axis of the second polarizing plate 38 when a voltage is applied. The direction is shifted.

  Thus, in order to make the alignment direction of the liquid crystal layer 33 different between the reflective display region R and the transmissive display region T, the first alignment film 32 and the second alignment film 34 may be liquid crystal by a rubbing method or a photo alignment method. When the process of regulating the orientation of the layer 31 is performed, the orientation regulating direction may be different between the reflective display region R and the transmissive display region T.

  The liquid crystal layer 33 gives a phase difference of ½ wavelength to the wavelength of incident visible light in both the reflective display region R and the transmissive display region T. As a result, in the reflective display region R, the second polarizing plate 38, the retardation layer 46, and the liquid crystal layer 33 can create broadband circularly polarized light, and external light reaching the reflective layer 14 can be transmitted at all visible wavelengths. It is close to circularly polarized light.

  According to the third embodiment, the following effects can be obtained.

  (1) In the liquid crystal display device 300, the uneven shape on the surface of the reflective layer 14 is flattened by the flattening layer 16, so that the flatness of the retardation layer 46 provided on the flattening layer 16 is improved. For this reason, since the layer thickness of the retardation layer 46 can be made more uniform, the optical compensation characteristics of the retardation layer 46 are improved. Further, the layer thickness of the liquid crystal layer 33 disposed to face the retardation layer 46 becomes more uniform. Thereby, the liquid crystal display device 300 having excellent display quality can be provided.

  In addition to the above embodiment, various modifications can be made. Hereinafter, a modification will be described.

(Modification 1)
In the liquid crystal display device of the above embodiment, the surface of the reflective layer 14 is made uneven by forming an uneven shape on the surface of the first insulating layer 13 that is the base of the reflective layer 14. It is not limited. The reflective layer 14 may be disposed on a base having a flat surface, and the surface of the reflective layer 14 itself may be formed in an uneven shape. Such a concavo-convex shape of the reflective layer can be formed by, for example, the surface tension of the droplets by disposing a material of the reflective layer containing a solvent by a droplet discharge method.

(Modification 2)
In the manufacturing method of the liquid crystal display device of the above embodiment, the mask 54 having different light transmittances in the multi-tone in the transmission portion 55 is used once in the positive photosensitive resin layer 15 in the planarization layer forming step. However, the present invention is not limited to such a form. A plurality of exposures may be performed using a plurality of masks having different opening diameters.

  In this case, each of the plurality of masks is a concentric circle centering on the position corresponding to the apex of the convex portion of the reflective layer 14, and has openings having different diameters stepwise with the outer periphery of the transmission portion 55 as the maximum diameter. is doing. If each of these masks is used to perform one exposure, the amount of light applied to the positive photosensitive resin layer 15 is maximized at the position corresponding to the vertex of the reflective layer 14, and the vertex The light transmittance can be reduced stepwise from the portion corresponding to the portion toward the portion corresponding to the bottom. In addition, when the vertex of the convex part of the reflective layer 14 is not at the center of the convex part planar shape, the center position of each opening part of the plurality of masks may be shifted in correspondence with the shape of the convex part.

(Modification 3)
In the manufacturing method of the liquid crystal display device of the above embodiment, the shape of the light shielding portion 51 of the mask 50 used in the first insulating layer forming step is circular, but is not limited to such a form. The shape of the light shielding part may be a polygon. Even if the shape of the light-shielding portion is a polygon, the planar shape of the convex portion of the first insulating layer 13 to be formed is substantially circular with the corners being bent. In this case, the shape of the transmissive portion of the mask used in the planarization layer forming step is the same polygon as the shape of the light shielding portion of the mask used in the first insulating layer forming step, and the polygon and the center position are the same in shape. You may change the transmittance | permeability of the light in a transmissive part.

(Modification 4)
In the manufacturing method of the liquid crystal display device of the above embodiment, the positive photosensitive resin is used as the photosensitive material for forming the planarization layer 16, but the present invention is not limited to such a form. A negative photosensitive resin may be used as the photosensitive material for forming the planarizing layer 16. In the case of using a negative photosensitive resin, the light transmittance distribution of the mask used for exposure in the planarization layer forming step may be reversed with respect to the mask 54 used in the case of the positive photosensitive resin. That is, the mask using the negative photosensitive resin has the lowest light transmittance at a position corresponding to the center 55a of the transmissive part 55, and from a position corresponding to the center 55a of the transmissive part 55 to a position corresponding to the outer peripheral part 55b. The light transmittance is increased stepwise, and the light transmittance is highest at the portion corresponding to the light shielding portion 56.

(Modification 5)
In the above embodiments, the FFS liquid crystal display device and the ECB liquid crystal display device have been described as examples. However, the present invention is not limited to this configuration, and may be applied to, for example, an IPS liquid crystal display device. The present invention may be applied to a VA (Vertical Alignment) type liquid crystal display device.

  In addition, what is necessary is just to apply a well-known technique for the material and processing method of the component which are not demonstrated in the above embodiment.

1 is a cross-sectional view illustrating a schematic configuration of a liquid crystal display device according to a first embodiment. FIG. 2 is a plan view showing a pixel region of the liquid crystal display device according to the first embodiment. 5 is a flowchart showing a method for manufacturing a liquid crystal display device. Sectional drawing explaining the manufacturing method of a liquid crystal display device. Sectional drawing explaining the manufacturing method of a liquid crystal display device. 6A and 6B illustrate a mask used for manufacturing a liquid crystal display device. 6A and 6B illustrate a mask used for manufacturing a liquid crystal display device. The graph which shows the transmittance | permeability distribution of a mask. Sectional drawing which shows schematic structure of the liquid crystal display device which concerns on 2nd Embodiment. Sectional drawing which shows schematic structure of the liquid crystal display device which concerns on 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... 1st board | substrate, 11 ... 1st base material, 12 ... 1st insulating material layer, 12a ... Removal part, 13 ... 1st insulating layer, 14 ... Reflective layer, 15 ... Positive type photosensitive resin layer , 15a ... convex portion, 16 ... flattening layer, 17 ... common electrode, 18 ... second insulating layer, 19 ... pixel electrode, 19a ... opening, 20 ... second substrate, 21 ... second substrate, 22 ... color filter layer, 23 ... protective layer, 24R, 24G, 24B ... sub-pixel, 25 ... pixel, 30 ... liquid crystal layer, 31 ... liquid crystal layer, 32 ... first alignment film, 33 ... liquid crystal layer, 34 ... first 2... Alignment film, 42... First retardation plate, 44... Second retardation plate, 36... First polarization plate, 38. 45 ... Alignment film, 46 ... Retardation layer, 50 ... Mask, 51 ... Shading part, 52 ... Transmission part, 54 ... Mask, 55 ... Transmission part, 55a ... Center, 5 b ... outer peripheral part, 56 ... light-shielding part, 60 ... first substrate, 62 ... first electrode, 70 ... second substrate, 72 ... second electrode, 80 ... first substrate, 90 ... second Substrate, 100 ... liquid crystal display device, 200 ... liquid crystal display device, 300 ... liquid crystal display device, R ... reflective display region, T ... transmissive display region.

Claims (11)

A liquid crystal display device comprising: a first substrate; a second substrate; and a liquid crystal layer positioned between the first substrate and the second substrate,
The first substrate includes a reflective layer disposed in a predetermined region and having a concavo-convex shape on a surface thereof, a planarization layer formed so as to cover the reflective layer, and at least one provided on the planarization layer And a liquid crystal display device. The liquid crystal display device according to claim 1,
A liquid crystal display device, wherein a common electrode and a pixel electrode are provided on the planarizing layer so that an electric field is generated in a direction parallel to the first substrate surface when a voltage is applied. . The liquid crystal display device according to claim 1,
A first electrode is provided on the planarizing layer,
The liquid crystal display device, wherein the second substrate includes a second electrode provided so as to face the first electrode. A liquid crystal display device comprising: a first substrate; a second substrate; and a liquid crystal layer positioned between the first substrate and the second substrate,
The first substrate includes a reflective layer having a concavo-convex shape on a surface thereof, a planarization layer formed so as to cover the reflective layer, and a retardation layer provided on the planarization layer. A liquid crystal display device characterized by the above. The liquid crystal display device according to any one of claims 1 to 4,
The first substrate further includes an underlayer,
The foundation layer has the concavo-convex shape in the predetermined region,
The liquid crystal display device, wherein the reflective layer is formed so as to cover the predetermined region on the base layer. A liquid crystal display device according to any one of claims 1 to 5,
A transmissive display area and a reflective display area as the predetermined area in one pixel area;
The liquid crystal display device, wherein the reflective layer is disposed in the reflective display region. A method of manufacturing a liquid crystal display device comprising: a first substrate; a second substrate; and a liquid crystal layer positioned between the first substrate and the second substrate,
A reflective layer forming step of forming a reflective layer having a concavo-convex shape on the surface in a predetermined region on the base material of the first substrate;
A photosensitive material arranging step of arranging a transparent photosensitive material so as to cover the reflective layer;
And a planarization layer forming step of planarizing the surface of the photosensitive material by exposing and developing the arranged photosensitive material,
In the planarization layer forming step, the amount of the photosensitive material removed by the development is the largest in the portion corresponding to the top of the uneven shape, and corresponds to the bottom of the uneven shape from the portion corresponding to the top. A method of manufacturing a liquid crystal display device, characterized in that the exposure is performed so as to decrease toward a portion to be performed. It is a manufacturing method of the liquid crystal display device according to claim 7,
The photosensitive material is a positive photosensitive resin,
In the flattening layer forming step, the intensity of light applied to the positive photosensitive resin during the exposure is highest at a portion corresponding to the apex, and from a portion corresponding to the apex to a portion corresponding to the bottom. A method of manufacturing a liquid crystal display device, characterized by being changed so as to be weakened. A method for manufacturing a liquid crystal display device according to claim 8,
In the planarization layer forming step, the positive photosensitive resin is irradiated with the light through a mask during the exposure,
The mask is formed such that the light transmittance is highest at a portion corresponding to the apex, and the light transmittance is reduced from a portion corresponding to the apex to a portion corresponding to the bottom portion. A method of manufacturing a liquid crystal display device. A method for manufacturing a liquid crystal display device according to any one of claims 7 to 9,
Before the reflective layer forming step, including a base layer forming step of forming a base layer on the substrate,
In the underlayer forming step, the uneven shape is formed on the surface of the underlayer in the predetermined region,
In the reflective layer forming step, a material for the reflective layer is disposed so as to cover the predetermined region of the base layer. It is a manufacturing method of the liquid crystal display device according to any one of claims 7 to 10,
A transmissive display area and a reflective display area as the predetermined area in one pixel area;
In the reflective layer forming step, the reflective layer is formed in the reflective display region.