JP2011090262A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reflection transmission type liquid crystal display device that obtains sufficient pixel display area in both reflection display mode and transmission display mode. <P>SOLUTION: The liquid crystal display device comprises a liquid crystal panel 40 having a liquid crystal layer 33 between an active matrix substrate 31 with a plurality of pixel areas 10P disposed in matrix and a counter substrate 32, and a back light for irradiating the liquid crystal panel 40 with light for transmission display. The active matrix substrate 31 comprises a reflection electrode layer 34 for reflecting external light for reflection display. The reflection electrode layer 34 is provided with a liquid metal 72 having reflectivity, a liquid metal layer 56 (liquid metal storage space) with the liquid metal 72 stored in a movable state, and a coil 73 (magnetic field generating part) for generating a magnetic field in the liquid metal layer 56. According to the magnetic field generated by the coil 73, the liquid metal 72 is moved to select reflection display mode or transmission display mode. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a reflective / transmissive liquid crystal display device that displays an image in both a reflective display mode and a transmissive display mode.

  Currently, liquid crystal display devices are widely used in electronic devices such as monitors, projectors, mobile phones, and personal digital assistants (PDAs). There are three types of such liquid crystal display devices: a reflection type, a transmission type, and a reflection / transmission type (also referred to as a semi-transmission type).

  Of these, the reflection-transmission type liquid crystal display device performs transmissive display using backlight light under relatively dark illumination such as indoors, while using illumination light under relatively bright illumination such as outdoors. Reflective display is performed. Thereby, a display with a high contrast ratio can be realized regardless of the surrounding brightness. In other words, reflection / transmission type liquid crystal display devices can be displayed under any illumination (in an optical environment) regardless of whether they are indoors or outdoors, and thus have been mounted on mobile devices such as mobile phones, PDAs, and digital cameras. ing.

  In such a reflection-transmission type liquid crystal display device, a reflection area (reflection subpixel) used in the reflection display mode and a transmission area (transmission subpixel) used in the transmission display mode are included in one pixel of the liquid crystal panel. Two types of display areas are formed (see Patent Document 1).

Japanese Patent Laying-Open No. 2006-139286 (released on June 1, 2006) Japanese Patent Laid-Open No. 1-283852 (published on November 15, 1989)

  FIG. 12 shows a configuration of one pixel in a conventional reflection / transmission type liquid crystal display device. One pixel region 100P of the liquid crystal display device 100 shown in FIG. 12 is a region surrounded by two adjacent source lines 111 and 111 and two adjacent auxiliary capacitance lines 113 and 113. A gate line 112 extends in parallel with the auxiliary capacity line 113 between the two auxiliary capacity lines 113 and 113.

  In the pixel region 100P, a gate electrode 112a drawn from the gate wiring 112, a source electrode 111a drawn from the source wiring 111, and a drain electrode 113a are provided. Element). Further, the drain electrode 113a is electrically connected to a pixel electrode (not shown) through the contact hole 114. The drain electrode 113a is connected to the auxiliary capacitance electrode 115 formed so as to overlap the auxiliary capacitance wiring 113 through the drain lead-out wiring 113c. The drain electrode 113a, the drain lead-out wiring 113c, and the auxiliary capacitance electrode 115 are formed in the same layer as the source electrode 111a. As a result, an auxiliary capacitance is formed between the auxiliary capacitance wiring 113 and the auxiliary capacitance electrode 115. Although not shown, a reflective electrode is partially formed in the pixel region 100P.

  With the above-described configuration, in the conventional reflective / transmissive liquid crystal display device 100, one pixel region 100P has two parts, a transmissive part used in the transmissive display mode and a reflective part used in the reflective display mode. It is divided into. As described above, in the conventional reflection / transmission type liquid crystal display device, it is necessary to allocate the entire area of the opening in the pixel region 100P to the reflection portion and the transmission portion, and the entire pixel region is used for transmission display or reflection display. There is a problem that the display area in each display mode is reduced as compared with a transmissive or reflective liquid crystal display device.

  The present invention has been made in view of the above problems, and an object thereof is to provide a reflection / transmission type liquid crystal display device capable of obtaining a sufficient pixel display area in both display modes of reflection display and transmission display. And

  In order to solve the above problems, a liquid crystal display device according to the present invention provides a liquid crystal panel having a liquid crystal layer between an active matrix substrate in which a plurality of pixel regions are arranged in a matrix and a counter substrate, and a transmissive display. A liquid crystal display device having a backlight for irradiating the liquid crystal panel with light, wherein the active matrix substrate includes a reflective electrode layer that reflects external light to perform reflective display, and the reflection The electrode layer is provided with a reflective liquid metal, a liquid metal accommodation space in which the liquid metal is accommodated in a movable state, and a magnetic field generation unit that generates a magnetic field in the liquid metal accommodation space. The liquid metal is moved by the magnetic field generated by the magnetic field generation unit, and switching between the reflective display and the transmissive display is performed.

  The liquid crystal display device of the present invention includes a backlight and a reflective electrode layer, and performs both display of images by transmissive display using the backlight as a light source and image display by reflective display using external light as the light source. This is a reflection / transmission type liquid crystal display device. The liquid crystal display device of the present invention includes a reflective liquid metal, a liquid metal storage space in which the liquid metal is stored in a movable state, and a magnetic field generation that generates a magnetic field in the liquid metal storage space. A reflective electrode layer having a portion.

  According to the above configuration, the liquid metal is generated in the pixel region (that is, the opening region) and outside the pixel region (that is, the non-opening region (light-shielding region) within the liquid metal accommodating space by the magnetic field generated by the magnetic field generation unit. ) To switch between reflective display and transmissive display. Accordingly, it is possible to realize reflective display and transmissive display in all pixel regions without dividing one pixel into a reflective display region and a transmissive display region.

  Therefore, according to the above configuration, it is possible to switch between the reflective display mode and the transmissive display mode without dividing the pixels. Therefore, the display pixel area can be widened in both display modes as compared with the conventional reflection / transmission type liquid crystal display device.

  In the liquid crystal display device of the present invention, the liquid metal may be a diamagnetic material.

  The diamagnetic material does not have spontaneous magnetization, and only when a magnetic field is applied, the substance is magnetized in the opposite direction of the magnetic field, and a force proportional to the product of the magnetic field and its gradient is generated in the direction opposite to the magnet. It is a magnetic material.

  When the liquid metal is a diamagnetic material, it is preferable to provide a magnetic field generator in a light shielding region outside the pixel region. Thereby, when the magnetic field generator generates a magnetic field, the liquid metal is deformed so as to repel the magnetic field generator by the electrowetting action, and the liquid metal is moved into the pixel region (opening region). Can do. Thereby, reflective display can be realized.

  In the liquid crystal display device of the present invention, the liquid metal may be mercury.

  According to said structure, the movable reflective electrode is realizable. Since mercury is a diamagnetic material, when the magnetic field generator applies a magnetic field, it is magnetized in a direction opposite to the generated magnetic field.

  In the liquid crystal display device of the present invention, the magnetic field generation unit may have a coiled structure.

  According to said structure, a magnetic field can be generated by an electromagnetic effect | action by sending an electric current through the said coil-shaped structure. In addition, the direction of the magnetic field to be generated can be changed depending on the direction of the flowing current.

  In the liquid crystal display device of the present invention, a raised portion having a gradient with the central portion of the pixel region as a vertex may be formed on the bottom surface of the liquid metal accommodating space.

  According to said structure, the movement of a liquid metal when making it transfer to reflective display mode from reflective display mode can be performed using the dead weight by the physical inclination of a protruding part. Therefore, power consumption can be reduced.

  In the liquid crystal display device of the present invention, the pixel electrode constituting the pixel region, the liquid crystal layer, and the counter substrate may be provided on the reflective electrode layer.

  According to the above configuration, the pixel electrode for driving the liquid crystal is provided on the reflective electrode layer, so that the liquid crystal display driving by the pixel electrode, the liquid crystal layer, and the counter substrate (counter electrode), and the reflection are performed. A liquid crystal panel that combines reflection display and transmission display on the electrode layer can be realized.

  In the liquid crystal display device of the present invention, the magnetic field generator may control generation of a magnetic field for each of the pixel regions.

  According to the above configuration, the display mode can be switched in units of one pixel, not in the entire display area unit of the liquid crystal panel. As a result, the pixel area in the reflective display mode and the pixel area in the transmissive display mode can coexist in one liquid crystal panel.

  In the liquid crystal display device according to the present invention, the reflective electrode layer includes a reflective liquid metal, a liquid metal storage space in which the liquid metal is stored in a movable state, and the liquid metal storage space. There is provided a magnetic field generating unit for generating a magnetic field, and the liquid metal moves by the magnetic field generated by the magnetic field generating unit to switch between the reflective display and the transmissive display.

  According to the present invention, it is possible to realize a reflection / transmission type liquid crystal display device capable of obtaining a sufficient pixel display area in both display modes of reflection display and transmission display.

FIG. 3 is a plan view showing a configuration of one pixel region in a liquid crystal panel provided in the liquid crystal display device shown in FIG. 2. It is a schematic diagram which shows the structure of the liquid crystal display device concerning one embodiment of this invention. It is sectional drawing which shows the structure of the XY part of the liquid crystal panel shown in FIG. It is a figure for demonstrating the manufacturing process of the TFT substrate with which the liquid crystal panel of this Embodiment was equipped. (A)-(e) shows each manufacturing process in process order. It is a figure for demonstrating the manufacturing process of the TFT substrate with which the liquid crystal panel of this Embodiment was equipped. (A)-(c) shows each manufacturing process after (e) of FIG. 4 in order of a process. It is a figure for demonstrating the manufacturing process of the TFT substrate with which the liquid crystal panel of this Embodiment was equipped. (A)-(c) shows each manufacturing process after (c) of Drawing 5 in order of a process. It is a top view which shows the structure of the coil contained in the TFT substrate in the liquid crystal panel of this Embodiment. (A) is a perspective view which shows the structure of the coil in this Embodiment, (b) is sectional drawing which shows the structure of the C1-D1 part of the coil shown in FIG. 7, (c) is a figure. 8 is a cross-sectional view showing a configuration of a C2-D2 portion of the coil shown in FIG. 7, and FIG. 8D is a cross-sectional view showing a configuration of a C3-D3 portion of the coil shown in FIG. FIG. 10 is a plan view for explaining the switching operation from the transmissive display mode to the reflective display mode in the pixel region of the liquid crystal panel of the present embodiment. FIG. 6 is a cross-sectional view for explaining the switching operation from the transmissive display mode to the reflective display mode in the pixel region of the liquid crystal panel of the present embodiment. In addition, (a) in the drawing shows the sectional configuration of the A1-B1 portion in (a) of FIG. 9, and (b) in the drawing shows the sectional configuration of the A2-B2 portion in (c) of FIG. Is shown. It is a figure for demonstrating the principle (electromagnetic action) of this invention. It is a schematic diagram which shows the pixel structure in the conventional reflective transmissive liquid crystal display device.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. Note that the present invention is not limited to this.

  For convenience of explanation, the drawings referred to below show only the main members necessary for explaining the present invention in a simplified manner among the constituent members of the embodiment of the present invention. Therefore, the liquid crystal display device according to the present invention may include any constituent member that is not shown in the drawings referred to in this specification. Moreover, the member dimension in each figure does not represent the dimension of an actual structural member faithfully and the dimension ratio of each member.

  In the present embodiment, an active matrix substrate having a plurality of pixel portions (pixel regions) arranged in a matrix in the vicinity of the intersection is arranged so that a plurality of source lines and a plurality of gate lines intersect. A liquid crystal display device will be described.

  The liquid crystal display device according to this embodiment is a reflection / transmission type liquid crystal display device configured to be able to switch between a reflection display mode and a transmission display mode. That is, in the liquid crystal display device according to the present embodiment, an image is displayed in a transmissive display mode using backlight light under relatively dark illumination such as indoors, while under a relatively bright illumination such as outdoors, The image is displayed in the reflective display mode using the ambient light with the backlight off.

  FIG. 2 shows a schematic configuration of the liquid crystal display device 10 according to the present embodiment. As shown in this figure, the liquid crystal display device 10 is provided with a backlight 50 on the back side of the liquid crystal panel 40. The liquid crystal panel 40 has a configuration sandwiched between a front-side polarizing plate 43a and a back-side polarizing plate 43b. Here, the front side means a side on which external light is incident on the liquid crystal panel 40, and the back side means a side on which a backlight is provided.

  Further, a front side λ / 4 plate 41a is provided as a retardation plate for realizing reflective display between the liquid crystal panel 40 and the front side polarizing plate 43a, and between the liquid crystal panel 40 and the back side polarizing plate 43b. A backside λ / 4 plate 41b is provided as another retardation plate between them.

  The λ / 4 plates 41a and 41b change the polarization state of light transmitted through the λ / 4 plates 41a and 41b. The polarizing plates 43a and 43b transmit only light having a specific polarization component.

  The liquid crystal panel 40 includes a TFT substrate (active matrix substrate) 31, a counter substrate (color filter substrate) 32, and a liquid crystal layer 33 provided between these substrates.

  The liquid crystal display device 10 of the present embodiment can display an image in two display modes, a transmissive display mode A and a reflective display mode B.

  That is, in the transmissive display mode A, transmissive display is performed by the irradiation light of the backlight 50 provided on the back side of the liquid crystal panel 40. The back side λ / 4 plate 41b is provided in order to cancel the influence of the front side λ / 4 plate 41a on the phase difference in this transmissive display (that is, to restore the changed polarization state).

  In the case of the reflective display mode B, a reflective liquid metal (Hg) disposed in a movable state in the liquid crystal panel 40 is moved into the pixel region, and this liquid metal forms a reflective electrode. Thus, reflective display using external light can be performed. At this time, correct black and white display can be performed by the front side λ / 4 plate 41 a provided in the liquid crystal display device 10.

  Specifically, for example, when the liquid crystal panel 40 is in a voltage application state by the front side λ / 4 plate 41a, external light incident from the front side polarizing plate 43a has a phase difference of 0 and the front side λ / 4 plate 41a. By adding the liquid crystal layer in a reciprocating manner, the polarization state is changed by λ / 2 and the linearly polarized light is shifted by 90 degrees with respect to the transmission direction of the front polarizing plate 43a. Display. On the other hand, when the liquid crystal panel 40 is in a state in which no voltage is applied, external light incident from the front-side polarizing plate 43a is added back and forth between the front-side λ / 4 plate 41a and the phase difference λ / 4 liquid crystal layer. Since the polarization state is changed by λ / 2 and the linearly polarized light is parallel to the transmission direction of the front-side polarizing plate 43a, the white color is displayed through the front-side polarizing plate 43a.

  Next, a specific configuration of the liquid crystal panel 40 will be described. FIG. 1 schematically shows the configuration of one pixel region 10P in the liquid crystal panel 40. Note that the pixel region 10P illustrated in FIG. 1 indicates a state of the transmissive display mode.

  As shown in FIG. 1, the pixel region 10 </ b> P is a region surrounded by two adjacent source lines 11 and 11 and two adjacent auxiliary capacitance lines 13 and 13. Note that the gate line 12 extends in parallel with the auxiliary capacity line 13 between the two auxiliary capacity lines 13 and 13.

  Further, in the pixel region 10P, a gate electrode 12a drawn from the gate wiring 12, a source electrode 11a drawn from the source wiring 11, and a drain electrode 13a are provided. Element). Further, the drain electrode 13 a is electrically connected to the pixel electrode 16 through the contact hole 14. The drain electrode 13a is connected to the auxiliary capacitance electrode 15 formed so as to overlap the auxiliary capacitance wiring 13 through the drain lead-out wiring 13c. The drain electrode 13a, the drain lead line 13c, and the auxiliary capacitance electrode 15 are formed in the same layer as the source electrode 111a. As a result, an auxiliary capacitance is formed between the auxiliary capacitance wiring 13 and the auxiliary capacitance electrode 15.

  Since the pixel region 10P shown in FIG. 1 is in the transmissive display mode, there is no reflective electrode in the region overlapping the pixel electrode 16. In the transmissive display mode, the liquid metal (specifically, mercury Hg) for forming the reflective electrode in the reflective display mode exists on the outer periphery of the pixel electrode 16 as shown in FIG. It is accommodated in a light shielding region (that is, a region overlapping with the source line 11 and the auxiliary capacitance line 13). Therefore, this portion is referred to as the Hg accommodating portion 17.

  FIG. 3 shows a cross-sectional configuration of the XY portion in the liquid crystal panel 40 of FIG. As described above, the liquid crystal panel 40 has a configuration in which the liquid crystal layer 33 is sandwiched between the TFT substrate 31 and the counter substrate 32.

  A reflective electrode layer 34 is provided in the TFT substrate 31. For convenience of explanation, in the TFT substrate 31, the structure below the reflective electrode layer 34 is a lower structure, and the structure above the reflective electrode layer 34 is an upper structure. First, the lower structure and the upper structure will be described.

  In the lower structure, a semiconductor layer 52 (polysilicon layer) is formed in a predetermined shape on a glass substrate 51 to which a base coat has been applied, and an insulating layer 53 is formed so as to cover it, and further on the upper layer. A gate electrode layer 54 constituting the auxiliary capacitance line 13 is formed. The gate electrode layer 54 is patterned into a predetermined shape to form the gate wiring 12, the auxiliary capacitance wiring 13, and the like. An interlayer insulating film 55 is provided further above the gate electrode layer 54.

  In the upper structure, a source electrode layer (not shown in FIG. 3) is formed on the insulating film 58 constituting the uppermost layer of the reflective electrode layer 34. The source electrode layer is patterned into a predetermined shape, and constitutes the source wiring 11, the auxiliary capacitance electrode 15, and the like. A planarizing film 61 is formed of an insulating material on the source electrode layer, and a pixel electrode 16 made of ITO or the like is formed thereon. Although not shown in FIG. 3, the pixel electrode 16 is patterned in accordance with each pixel region, and each pixel electrode 16 is connected to the drain electrode 13 a formed of the source electrode layer through the contact hole 14. Has been. An alignment film 62 is formed on the upper layer of the pixel electrode 16, and the alignment film 62 is the uppermost layer of the TFT substrate 31.

  Although not shown in FIG. 3, a gate electrode 12a formed in the same layer as the gate wiring 12, a semiconductor layer 52, a source electrode 11a and a drain electrode 13a formed in the same layer as the source wiring 11 are stacked. Thus, the TFT 21 is configured.

  The lower structure and upper structure of the TFT substrate 31 described above have the same configuration as that of a conventional active matrix liquid crystal panel. On the other hand, the reflective electrode layer 34 described below has a configuration that is not found in a conventional liquid crystal panel.

  As shown in FIG. 3, the reflective electrode layer 34 includes a liquid metal layer 56 (liquid metal storage space) in which a liquid metal 72 (specifically, Hg) is movably stored, and an interlayer stacked on the liquid metal layer 56. A protective film 57 and an insulating film 58 are included. Note that the cross section shown in FIG. 3 is a cross section of the XY portion of FIG. 1 and includes the Hg accommodating portion 17. The Hg accommodating portion 17 is provided with a coil 73 (magnetic field generating portion) for generating a magnetic field in the liquid metal layer 56.

  In addition, it is preferable that the coil 73 is provided in the outer periphery of the Hg accommodating part 17 without a gap. This is because if a gap with a certain width exists between the coils, a magnetic flux space opposite to the inside of the coil exists between the coils (see FIG. 11A), and the liquid metal 72 is replaced by a pixel. This is because a magnetic force opposite to the magnetic force to be moved into the region is generated, and there is a possibility that the liquid metal 72 cannot be reliably moved into the pixel region.

  Further, the bottom surface of the liquid metal layer 56 in the reflective electrode layer 34 is provided with a gradient that inclines from the apex to the end with the center of the pixel region 10P (pixel central portion C shown in FIG. 1) as the apex. The raised portion 71 is formed. Note that the pixel central portion C only needs to be positioned substantially at the center of the pixel region 10P, and does not have to be strictly positioned at the center of the pixel region. In other words, when the magnetic field is not generated in the liquid metal layer 56, the bottom surface of the liquid metal layer 56 is such that the liquid metal (mercury) can move out of the pixel region 10P by its own weight. It suffices if the raised portion 71 is formed.

  The counter substrate 32 has a configuration in which a color filter layer and a counter electrode are laminated in this order on a glass substrate 63, and an alignment film 64 is formed as the uppermost layer. The configuration of the conventional liquid crystal panel can also be applied to the configuration of the counter substrate 32.

  Here, a specific structure of the coil 73 (coiled structure) will be described. FIG. 7 shows a planar configuration when the coil 73 is viewed from the upper electrode 76 side. 8A shows a three-dimensional structure of the coil 73, FIG. 8B shows a cross-sectional configuration of the C1-D1 portion of the coil 73 shown in FIG. 7, and FIG. ) Shows a cross-sectional configuration of the C2-D2 portion of the coil 73 shown in FIG. 7, and FIG. 8D shows a cross-sectional configuration of the C3-D3 portion of the coil 73 shown in FIG.

  As shown in FIG. 7, the coil 73 includes a lower electrode 74 and an upper electrode 76, and the lower electrode 74 includes a plurality of parallel linear structures. The upper electrode 76 is also configured by a plurality of parallel linear structures, and both ends of each linear structure overlap one end of two adjacent linear structures constituting the lower electrode 74, respectively. The pattern is formed as follows. 8B and 8D, the upper electrode 76 extends to the lower electrode 74 at the end of each linear structure, and the upper electrode 76 and the lower electrode 74 are connected to each other. Yes. That is, as shown in FIG. 8A, the upper electrode 76 ′ is partially embedded in the coil interlayer insulating film 75 existing between the upper electrode 76 and the lower electrode 74.

  Thus, the coil 73 has a helical coil structure by a combination of the lower electrode 74 and the upper electrode 76.

  In the present embodiment, a magnetic field is generated in the liquid metal layer 56 by passing a current through the coil 73. Therefore, the coil 73 is connected to a switching element (not shown) such as a transistor, and current on / off control is performed via the switching element.

  Further, in the present embodiment, the coil 73 and the switching element that performs on / off control of the current with respect to the coil 73 are individually provided for each pixel region 10P. Therefore, the display mode can be switched in units of one pixel, not in the entire display area unit of the liquid crystal panel 40. Accordingly, the pixel area 10P in the reflective display mode and the pixel area 10P in the transmissive display mode can coexist in one liquid crystal panel 40. However, the present invention is not limited to such a configuration, and display mode switching may be performed collectively in the entire display area of the liquid crystal panel (all pixel areas).

  Note that the coil driving switching element (transistor) may have the same configuration as the pixel electrode driving transistor. Accordingly, no special manufacturing process is required for the coil driving switching element, and the coil driving switching element can be formed simultaneously with the pixel electrode driving transistor.

  Also, when switching the display mode in units of one pixel, all the coils included in one pixel area are controlled on / off in the same manner according to the switching of the display mode. There is no need to drive. Therefore, there is no problem even if all the coils included in one pixel unit are connected, and it is sufficient that at least one coil driving switching element exists in one pixel region.

  In addition, the coil driving switching element can be disposed in the vicinity of each pixel like a pixel electrode driving transistor, or can be disposed in the peripheral circuit portion on the outer periphery of the panel outside the display area. There is no.

  Next, a method for manufacturing the TFT substrate 31 will be described with reference to FIGS. 4, 5, and 6.

  4A to 4E, FIG. 5A to FIG. 5C, and FIG. 6A to FIG. 6C, the manufacturing process of the TFT substrate 31 is shown in the order of steps.

  First, as shown in FIG. 4A, a base coat is applied on a glass substrate 51 to form a semiconductor layer 52, an insulating layer 53, and a gate electrode layer 54 by a general thin film transistor forming process.

  Next, as shown in FIG. 4B, an interlayer insulating film 55 is formed so as to cover the gate electrode layer 54 patterned in a predetermined shape, and a gradient as shown in the figure is applied by a photolithography process. A resist pattern 81 is formed.

  Next, as shown in FIG. 4C, the interlayer insulating film 55 is wet-etched with BHF or the like, and the center of the opening region (region where the pixel electrode 16 is formed) is set at 10 to 15 degrees. A raised portion 71 having a gradient is formed.

  Next, as shown in FIG. 4D, after the lower electrode layer 74, which is the material of the coil 73, is formed by sputtering using a metal material such as Ti to a thickness of 100 nm, for example. Then, a resist pattern 82 having a predetermined shape (a structure of the lower electrode 74 having a shape as shown in FIG. 7) is formed by a photolithography process.

  Next, as shown in FIG. 4E, after the lower electrode layer 74 is etched, the resist 82 is removed, and the lower electrode 74 of the coil 73 is formed.

Subsequently, a coil interlayer insulating film (for example, SiO ₂ film) 75 is formed with a thickness of 100 nm on the lower electrode 74, and then a resist pattern is formed and patterned. In the patterning here, holes for connecting the lower electrode 74 and the upper electrode 76 constituting the coil 73 are formed in the coil interlayer insulating film 75.

  After that, the upper electrode layer 76 was formed on the coil interlayer insulating film 75 by a sputtering method using a metal material such as Ti so as to have a film thickness of 100 nm, for example, and was formed in the coil interlayer insulating film 75. After embedding a metal material such as Ti in the hole, patterning is performed by forming a resist pattern having a predetermined shape (the structure of the upper electrode 76 having a shape as shown in FIG. 7) by a photolithography process. Thereby, the structure of the coil 73 as shown in FIG. 7 is completed.

  Next, as shown in FIG. 5A, a resist 83 is applied so that the upper electrode 76 of the coil 73 is exposed. Here, the resist 83 may be thickly applied so as to cover the upper electrode 76 to flatten the surface, and then the resist may be retracted so that the surface of the upper electrode 76 is exposed by etch back.

  Next, after forming an interlayer protective film (for example, SiNx film) 57 to a thickness of 200 nm on the resist 83, a resist pattern 84 having a predetermined shape is formed as shown in FIG. A hole 57a for removing 83 and for injecting liquid metal (Hg) 72 is formed.

  Thereafter, the TFT substrate 31 is immersed in a stripping solution to remove the resist 84 on the interlayer protective film 57 and the resist 83 for forming a hollow space, as shown in FIG.

  By the steps (a) to (c) in FIG. 5 described above, a hollow space (liquid metal accommodating space) in which the liquid metal (Hg) 72 is enclosed in the liquid metal layer 56 is formed. As a method for forming the hollow space, the method described in Patent Document 2 can be used.

  Subsequently, as shown in FIG. 6A, the TFT substrate 31 is immersed in the liquid metal layer, and the liquid metal (Hg) 72 is pressed into the hollow space from the hole 57a.

Thereafter, as shown in FIG. 6B, a coating type insulating film (for example, SiO ₂ film) 58 is formed on the interlayer protective film 57 by using a spin on glass method or the like to close the hole 57a. Apply at 50-100 nm. Thereafter, an insulating film 58 is formed through a baking process.

  Next, after forming a source metal layer, it is patterned into a predetermined shape to form the source wiring 11, the drain electrode 13a, the auxiliary capacitance electrode 15, and the like. Thereafter, as shown in FIG. 6C, a planarizing film 61 is formed, and the pixel electrode 16 is formed in a predetermined shape on the planarizing film 61. In FIG. 6C, the source metal layer is not shown. In FIG. 6C, the pixel electrode 16 is not patterned, but is actually patterned into a predetermined shape.

  Finally, the alignment film 62 is formed on the uppermost layer of the TFT substrate 31 to complete the TFT substrate 31. Then, the TFT substrate 31 and the counter substrate 32 are bonded together, and liquid crystal is injected therebetween, whereby a liquid crystal panel 40 as shown in FIG. 3 is obtained.

  The liquid crystal panel 40 according to the present embodiment includes the reflective electrode layer 34 having the above-described configuration, so that switching between transmissive display and reflective display can be performed in the pixel region 10P. That is, a magnetic field is generated by passing a current through the coil 73 in the reflective electrode layer 34 provided in the liquid crystal panel 40. Then, the liquid metal (Hg) 72 is moved from the outside of the pixel area (that is, the light shielding area) to the inside of the pixel area (that is, the opening area) by the magnetic action with respect to the magnetic field generated here. Switching can be done.

  Here, the switching operation between the transmissive display mode and the reflective display mode in the liquid crystal display device 100 will be described with reference to FIGS.

  First, the principle of moving the liquid metal in the present invention will be described with reference to FIG. As shown in FIG. 11A, when a current in the direction of the arrow in FIG. 11 is passed through the coil 200, a magnetic field parallel to the axis of the coil is generated inside the coil 200 by electromagnetic action.

  FIG. 11B shows an enlarged part of the coil 200 shown in FIG. 11A and shows the relationship between the direction of current flowing in the coil 200 and the magnetic field. When a current having a direction as shown in FIG. 11 (b) is passed through the coil 200, an arrow in the drawing indicates that each conductor of the coil 200 is surrounded by a right-hand rule (see FIG. 11 (c)). A magnetic field (line of magnetic force) as shown is generated. This magnetic field is all directed in the same direction inside the coil 200 (from the right to the left in the example in the figure). Thus, the coil 200 has a function like a magnet in which the end portion where the magnetic lines of force are generated is an N pole and the end portion where the magnetic lines of force are output is an S pole.

  In the present invention, using the electromagnetic action as described above, a current in a predetermined direction is passed through the coil 73 to generate a magnetic field in the coil 73. Electrowetting action based on the relationship between the magnetic properties of the liquid metal and the generated magnetic field [References: JP 2007-512121 (published May 17, 2007), JP 2008-197296 (published August 28, 2008) )] To move the liquid metal (Hg) 72.

  In this embodiment, since mercury Hg which is a diamagnetic material is used as the liquid metal 72, the liquid metal 72 moves so as to repel the direction of the magnetic field. For example, as shown in FIG. 3, when a current in a predetermined direction is passed through the coil 73 and a magnetic field is generated in the direction of arrow A, mercury (Hg), which is a diamagnetic material, is in a direction opposite to the magnetic field. Since it is magnetized, a repulsive force (demagnetizing force) B works. As a result, the liquid metal (Hg) 72 moves in the direction of the arrow C.

  9A to 9C show how the pixel region 10P in the liquid crystal panel 40 is switched from the transmissive display mode to the reflective display mode. 10A shows a cross-sectional configuration of the A1-B1 portion in the transmissive display mode shown in FIG. 9A, and FIG. 10B shows the cross-sectional configuration of FIG. A cross-sectional configuration of the A2-B2 portion in the reflective display mode shown in FIG. In FIGS. 10A and 10B, the source wiring 11 formed of the source electrode layer is not shown.

  In the transmissive display mode shown in FIGS. 9A and 10A, no current flows through the coil 73 in the reflective electrode layer 34, and the liquid metal 72 does not flow due to the gradient of the raised portion 71. It is accommodated in the Hg accommodating part 17 outside the pixel region 10P. Therefore, the pixel region 10P becomes a transmissive portion, and light from the backlight 50 is transmitted from the liquid crystal panel 40, thereby realizing transmissive display.

  Here, when a current in a predetermined direction is passed through the coil 73 to generate a magnetic field, the liquid metal 72 that is a diamagnetic material is repelled from the coil 73 as shown by the arrow in FIG. It moves toward the center part C.

  Accordingly, the reflective display mode is set during a period in which a current flows through the coil 73. That is, as shown in FIG. 9C and FIG. 10B, the liquid metal 72 moves from the Hg accommodating portion 17 into the pixel region 10P, and the reflection of the liquid metal 72 causes the inside of the pixel region 10P to move. It becomes a reflection part. Thereby, the reflective display which uses external light as a light source is implement | achieved. Here, since the magnetic field disappears when the current of the coil 73 is stopped, the liquid metal 72 is moved again to the Hg accommodating portion 17 outside the pixel region due to the inclination of the raised portion 71, and the pixel region 10P becomes a transmissive portion.

  As described above, the liquid crystal display device 10 according to the present embodiment includes the reflective liquid metal (specifically, Hg) 72 and the liquid metal layer 56 in which the liquid metal 72 is accommodated in a movable state. And a TFT substrate 31 having a reflective electrode layer 34 having a coil 73 for generating a magnetic field in the liquid metal layer 56.

  According to this configuration, in the reflective electrode layer 34, the liquid metal 72 is caused to flow in the pixel area 10 </ b> P (that is, the opening area) and outside the pixel area (that is, the light shielding area) in the liquid metal layer 56 by the magnetic field generated by the coil 73. Or it moves between Hg accommodating parts 17), and switching between reflective display and transmissive display is performed.

  Specifically, in the transmissive display mode, since the liquid metal 72 is accommodated in the Hg accommodating portion 17 outside the pixel area, the light from the backlight 50 is transmitted in the pixel area 10P. The liquid crystal layer 33 is driven by the potential difference between each pixel electrode 16 and the counter electrode on the counter substrate 32 side, and transmissive display is performed.

  When shifting from the transmissive display mode to the reflective display mode, a current is passed through the coil 73, and the liquid metal 72 is sent into the pixel region 10P by electromagnetic action. As a result, a reflective electrode is formed below the pixel electrode 16 by the reflective liquid metal 72 in the pixel region 10P. The external light reflected by the reflective electrode serves as a light source, and the liquid crystal layer 33 is driven by the potential difference between the reflective electrode in each pixel region 10P and the counter electrode on the counter substrate 32 side, thereby performing a reflective display.

  Therefore, according to the above configuration, the reflective display mode and the transmissive display mode can be switched without dividing one pixel into the reflective display region and the transmissive display region. Therefore, the display pixel area can be increased in both display modes as compared with the conventional reflection / transmission type liquid crystal display device.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  By using the liquid crystal display device of the present invention, switching between the transmissive display mode and the reflective display mode can be performed without dividing one pixel region. Therefore, the liquid crystal display device of the present invention can be applied to a reflection / transmission type liquid crystal display device. The present invention can be applied without particular limitation as long as it is a reflection / transmission type liquid crystal panel, regardless of the type of liquid crystal driving such as TN mode and VA mode.

DESCRIPTION OF SYMBOLS 10 Liquid crystal display device 10P Pixel area | region 11 Source wiring 11a Source electrode 12 Gate wiring 12a Gate electrode 13 Auxiliary capacity wiring 13a Drain electrode 13c Drain lead-out wiring 14 Contact hole 15 Auxiliary capacity electrode 16 Pixel electrode 17 Hg accommodating part 21 TFT (transistor, switching) element)
31 TFT substrate (active matrix substrate)
32 Counter substrate 33 Liquid crystal layer 34 Reflective electrode layer 40 Liquid crystal panel 50 Backlight 56 Liquid metal layer (liquid metal accommodating space)
71 Raised portion 72 Liquid metal (Hg)
73 Coil (Magnetic field generator, coiled structure)

Claims (7)

A liquid crystal display having a liquid crystal panel having a liquid crystal layer between an active matrix substrate in which a plurality of pixel regions are arranged in a matrix and a counter substrate, and a backlight for irradiating the liquid crystal panel with light for transmissive display A device,
The active matrix substrate includes a reflective electrode layer that reflects external light in order to perform reflective display,
In the reflective electrode layer,
A reflective liquid metal;
A liquid metal storage space in which the liquid metal is stored in a movable state; and
A magnetic field generating section for generating a magnetic field in the liquid metal containing space is provided,
The liquid crystal display device, wherein the liquid metal is moved by the magnetic field generated by the magnetic field generation unit to switch between the reflective display and the transmissive display.   The liquid crystal display device according to claim 1, wherein the liquid metal is a diamagnetic material.   The liquid crystal display device according to claim 1, wherein the liquid metal is mercury.   The liquid crystal display device according to claim 1, wherein the magnetic field generator has a coiled structure.   5. The liquid crystal display according to claim 1, wherein a raised portion having a gradient with a central portion of the pixel region as a vertex is formed on a bottom surface of the liquid metal containing space. apparatus.   6. The liquid crystal according to claim 1, wherein a pixel electrode constituting the pixel region, the liquid crystal layer, and the counter substrate are provided on the reflective electrode layer. Display device.   The liquid crystal display device according to claim 1, wherein the magnetic field generation unit controls generation of a magnetic field for each of the pixel regions.

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