JP2007171442A - Liquid crystal display element and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transflective liquid crystal display element having an improved visual impact and bringing about improved sense of beauty of an apparatus on which the display element is mounted, and a liquid crystal display device which uses the transflective display element. <P>SOLUTION: In the transflective liquid crystal display element 2 having a liquid crystal 30 sealed in a gap between mutually opposing pixel and counter substrates 10 and 20, and pixels 5, each of which having a reflective section 7 and a transmissive section 6 adjacent to each other, arranged in a matrix, a color filter 21 which is arranged on the transmissive section 6 and colors light transmitted by an adjacent pixel 5 with a different color, and a coloring layer 22 which is arranged on the reflective section 7 and colors light transmitted by an adjacent pixel 5 with an identical color are provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a transflective liquid crystal display element having a reflective portion and a transmissive portion, and a liquid crystal display device.

  Patent Document 1 discloses a transflective liquid crystal display element that has a reflective portion and a transmissive portion and is capable of color display and monochrome display.

  In this liquid crystal display element, liquid crystal is sealed between a pixel substrate and a counter substrate facing each other. The pixel substrate has pixel electrodes and switching elements provided for each pixel arranged in a matrix, and the counter substrate has a counter electrode facing the pixel electrode.

  The pixel electrode includes an adjacent reflective electrode and a transparent electrode, and includes a reflective portion including the reflective electrode and a transmissive portion including the transparent electrode. A color filter is formed only on the transmission part on the counter substrate. The color filter colors transmitted light in red (R), green (G), and blue (B) that are different in adjacent pixels.

The light emitted from the backlight provided on the back surface of the liquid crystal display element is transmitted through the transmission part, and is colored by a color filter to display a color image. Light incident from the display surface side of the liquid crystal display element is reflected by the reflecting electrode of the reflecting portion. Since a color filter is not provided in the reflection unit, for example, a monochrome image with a white background and a black character or the like is displayed. The brightness at the time of reflective display is omitted by omitting the color filter, and the visibility of the image can be improved. Further, when the image is not displayed, the entire display area is visually recognized as white by reflected light, for example.
JP 2004-20610 A

  However, according to the conventional liquid crystal display element, a white or black image or a display area is visually recognized when performing reflective display or non-display. For this reason, the display is not interesting and the visual effect is low, and when the liquid crystal display element is mounted on a device such as a mobile phone, the color arrangement of the mobile phone or the like is not unified, and the aesthetic appearance may be impaired.

  An object of the present invention is to provide a transflective liquid crystal display element capable of improving the visual effect and improving the aesthetics of a mounted device, and a liquid crystal display device using the transflective liquid crystal display element.

  In order to achieve the above object, the present invention provides a transflective liquid crystal display element in which liquid crystal is sealed between opposing substrates, and pixels in which a reflective portion and a transmissive portion are adjacent are arranged in a matrix. And a color filter that colors the transmitted light in a different color in adjacent pixels, and a colored layer that is disposed in the reflection portion and colors the transmitted light in the same color in adjacent pixels. It is said.

  According to this configuration, the light emitted from the backlight provided on the back surface of the liquid crystal display element is transmitted through the transmission part, and is colored by the color filter to display a color image. In addition, light incident from the display surface side of the liquid crystal display element is transmitted through the colored layer, reflected by the reflecting portion, and then transmitted through the colored layer again and emitted. Thereby, the emitted light is colored with a single color, and for example, an image such as a black character is displayed on a bluish background color. When the image is not displayed, for example, a bluish color is displayed on the entire display area by the reflected light of the reflecting portion.

  According to the present invention, in the liquid crystal display element having the above configuration, a liquid crystal thickness adjusting layer that makes the thickness of the liquid crystal of the reflecting portion narrower than the transmitting portion is provided in the reflecting portion, and the colored layer is formed from the liquid crystal thickness adjusting layer. It is characterized by that.

  According to this configuration, the light emitted from the backlight provided on the back surface of the liquid crystal display element is transmitted through the liquid crystal in the transmission section. The light incident from the display surface side of the liquid crystal display element is transmitted through the liquid crystal narrowed by the liquid crystal thickness adjusting layer, reflected by the reflecting portion, and transmitted again through the liquid crystal and emitted. The optical path length of the light passing through the liquid crystal at the reflecting portion and the transmitting portion is made substantially equal by the liquid crystal thickness adjusting layer, and the optical loss is reduced.

  According to the present invention, in the liquid crystal display element having the above configuration, a pixel electrode provided for each pixel is formed on one of the substrates, and the color filter and the liquid crystal thickness adjusting layer are formed on the other substrate. It is said. According to this configuration, the pixel electrode provided for each pixel is formed on one substrate, and the counter electrode, the color filter, and the liquid crystal thickness adjusting layer formed on the other substrate can be formed across a plurality of pixels.

  According to the present invention, in the liquid crystal display element having the above structure, the colored layer includes a light color pigment. According to this structure, the light which permeate | transmits a colored layer and is radiate | emitted from a reflection part is colored lightly.

  According to the present invention, in the liquid crystal display element having the above structure, the liquid crystal is in a light-shielding state when a voltage is applied between the substrates. According to this configuration, light is transmitted through the liquid crystal when the liquid crystal display element is not displayed, and light transmitted through the colored layer is emitted from the reflective portion. Thereby, the whole display area is colored and visually recognized.

  In addition, a liquid crystal display device of the present invention includes the liquid crystal display element having the above-described configuration and a backlight disposed on the back surface of the liquid crystal display element.

  According to the present invention, since the colored layer that is arranged in the reflective portion and colors the transmitted light to the same color in the adjacent pixels is provided, for example, when performing reflective display, the background color is colored to increase the interest of the display. The visual effect can be improved. In addition, the background color and display area of the liquid crystal display element can be unified with the color scheme of the device on which the liquid crystal display device is mounted, so that aesthetics can be improved.

  Further, according to the present invention, since the colored layer is composed of the liquid crystal thickness adjusting layer, the colored layer can be easily realized without increasing the number of steps.

  According to the present invention, since the pixel electrode is formed on one substrate and the color filter and the liquid crystal thickness adjusting layer are formed on the other substrate, the colored layer can be formed across a plurality of pixels. It can be formed easily.

  Further, according to the present invention, since the colored layer contains a light color pigment, the colored layer can be easily realized and the visibility of an image displayed in black can be improved by shielding the liquid crystal. In addition, since light is colored light, a decrease in luminance can be suppressed.

  According to the present invention, the liquid crystal is in a light-shielding state when a voltage is applied between the substrates. Therefore, when the liquid crystal display element is not displayed, light is transmitted through the liquid crystal, and the entire display region is colored by the reflecting portion. Therefore, it is possible to easily unify the color scheme of the devices on which the liquid crystal display device is mounted.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view showing the liquid crystal display element of the first embodiment. In the liquid crystal display device 1, a backlight 3 is disposed on the back surface of the liquid crystal display element 2. In the liquid crystal display element 2, the pixel substrate 10 and the counter substrate 20 are arranged to face each other with a rib 31 through a predetermined gap, and the liquid crystal 30 is sealed in the gap. The pixel substrate 10 and the counter substrate 20 are made of an insulating transparent member such as glass or transparent resin.

  FIG. 2 is a schematic plan view of the pixel substrate 10. FIG. 1 shows a schematic diagram of the AA cross section of FIG. 2, and the gate line 11 of FIG. 2 is not shown. A plurality of parallel gate lines 11 are formed on the pixel substrate 10. On the gate line 11, a large number of parallel source lines 12 orthogonal to the gate line 11 are formed via an insulating film. As a result, the pixels 5 including the region surrounded by the gate lines 11 and the source lines 12 are arranged in a matrix.

  A switching element (not shown) made of TFT is provided at the intersection of the gate line 11 and the source line 12. The gate line 11 and the source line 12 are connected to the gate and source of the switching element, respectively. A pixel electrode 15 corresponding to each pixel 5 is connected to the drain of the switching element.

  In FIG. 1, the pixel electrode 15 is made of a transparent electrode made of a light-transmitting conductive material such as ITO, and is formed on the pixel substrate 10 via an interlayer insulating film 14. A reflective plate 16 is provided between the pixel electrode 15 and the interlayer insulating film 14 in a part of each pixel 5. The reflector 16 is made of metal such as aluminum and reflects light. As a result, the transmissive portion 6 where the reflective plate 16 is not provided and the reflective portion 7 provided with the reflective plate 16 are formed in one pixel 5.

  The reflection plate 16 is subjected to scattering treatment on the surface so as to scatter the reflected light. Note that a reflective electrode may be formed on the pixel electrode 15 of the reflective portion 7 instead of the reflective plate 16. An alignment film 17 that aligns the molecules of the liquid crystal 30 is provided on the pixel electrode 15.

  A color filter 21 is formed in the transmissive portion 6 on the counter substrate 20 to color the transmitted light in red (R), green (G), and blue (B). As shown in FIG. 2, the color filter 21 is divided for each pixel 5, and different colors are colored in the adjacent pixels 5. Normally, one dot on the screen is constituted by three pixels 5 each having an RGB color filter 21.

  A liquid crystal thickness adjusting layer 22 is formed on the reflective portion 7 on the counter substrate 20. The liquid crystal thickness adjusting layer 22 is made of a transparent resin and reduces the optical loss by making the optical path length of the light passing through the liquid crystal 30 of the reflecting portion 7 substantially equal to the optical path length of the light passing through the liquid crystal 30 of the transmitting portion 6. To do. In addition, as shown in FIG. 2, the liquid crystal thickness adjustment layer 22 is formed across the reflective portions 7 of the plurality of pixels 5. Thereby, it can be formed even if the patterning accuracy is low, and the liquid crystal thickness adjusting layer 22 can be easily formed by reducing the number of steps.

  The liquid crystal thickness adjusting layer 22 contains a light color pigment. Thereby, the liquid crystal thickness adjusting layer 22 constitutes a colored layer that colors the transmitted light in a bluish color or a sepia color. The light may be colored by the liquid crystal thickness adjusting layer 22 into a color such as light green that does not cause eyestrain. Since the liquid crystal thickness adjusting layer 22 is formed across the plurality of pixels 5, the same color is colored in the adjacent pixels 5.

  On the color filter 21 and the liquid crystal thickness adjusting layer 22, a counter electrode 23 is provided to face the pixel electrode 15. The counter electrode 23 is made of a transparent electrode such as ITO, and the capacitance of the liquid crystal 30 is formed by the pixel electrode 15 and the counter electrode 23. An alignment film 24 for aligning the molecules of the liquid crystal 30 is provided on the counter electrode 23.

  In the liquid crystal display device 1 having the above configuration, when the gate of the switching element becomes Hi level by the scanning signal supplied through the gate line 11 serving as the scanning line, the switching element becomes conductive. As a result, a voltage is applied between the pixel electrode 15 and the counter electrode 23, and a video signal supplied via the source line 12 serving as a signal line is written into the capacitance of the liquid crystal 30. Note that the liquid crystal 30 is in a light-transmitting state when no voltage is applied between the pixel electrode 15 and the counter electrode 23, and the liquid crystal 30 is in a light-shielding state when a voltage is applied between the pixel electrode 15 and the counter electrode 23. It is configured as follows.

  When transmissive display is performed, the backlight 3 is turned on, and light emitted from the backlight 3 passes through the transmissive portion 6 of the pixel 5 in which the liquid crystal 30 is transmissive. The light transmitted through the transmission part 6 is colored by the color filter 21 and emitted. Thereby, the liquid crystal display device 1 displays a color image.

  When reflective display is performed with the backlight 3 turned off, light enters from the display surface of the liquid crystal display element 2. Incident light from the liquid crystal display element 2 is transmitted through the liquid crystal thickness adjusting layer 22, and only the pixels 5 in which the liquid crystal 30 is in the transmission state are transmitted through the liquid crystal 30. Then, the light passing through the reflecting portion 7 is reflected by the reflecting plate 16. The reflected light of the reflecting plate 16 passes through the liquid crystal 30 and the liquid crystal thickness adjusting layer 22 and is emitted from the display surface of the liquid crystal display element 2. Incident light from the display surface and reflected light from the reflecting plate 16 are colored when passing through the liquid crystal thickness adjusting layer 22 to color outgoing light.

  Thereby, the liquid crystal display device 1 displays, for example, a monochrome image in which black characters or the like are visually recognized on a bluish color or a sepia background. When the liquid crystal thickness adjusting layer 22 contains a light-colored pigment, the visibility of black characters and the like by the pixels 5 in which the liquid crystal 30 is in a light-shielded state can be maintained satisfactorily. Moreover, since light is colored lightly by the liquid crystal thickness adjusting layer 22, a decrease in luminance can be suppressed. Note that the liquid crystal 30 of the pixel 5 serving as the background may be displayed in black in a light-shielded state, and characters or the like may be colored.

  Further, when an image is not displayed, no voltage is applied between the pixel electrode 15 and the counter electrode 23, and the liquid crystal 30 in the entire display region is in a transmissive state. Thereby, the light incident from the display surface is visually recognized by the reflecting portion 7 in, for example, a bluish color or a sepia color.

  According to the present embodiment, since the reflective portion 7 is provided with the colored layer composed of the liquid crystal thickness adjusting layer 22, for example, the background color is colored when the reflective display is performed, and the visual effect is improved by increasing the interest of the display. it can. In addition, the background color of the liquid crystal display element 2 and the color of the display area can be unified with the color scheme of a device such as a mobile phone on which the liquid crystal display device 1 is mounted to improve aesthetics.

  Next, FIG. 3 shows a side sectional view of the liquid crystal display device of the second embodiment. For convenience of explanation, the same reference numerals are given to the same parts as those in the first embodiment shown in FIGS. In this embodiment, a colored layer 29 containing a pigment is formed in the reflective portion 7 on the counter substrate 20 in a separate process from the color filter 21, and a liquid crystal thickness adjusting layer 22 not containing a pigment is further formed on the colored layer 29. It is formed in a separate process. Other parts are the same as those in the first embodiment. The liquid crystal thickness adjusting layer 22 which is formed and does not contain a pigment is formed on the colored layer 29. Other parts are the same as those in the first embodiment.

  The colored layer 29 contains a light-colored pigment, and the colored layer 29 colors the transmitted light into a bluish color or a sepia color. Similarly to the first embodiment, when the backlight 3 is turned off to perform reflection display, light enters from the display surface of the liquid crystal display element 2. Incident light of the liquid crystal display element 2 is transmitted through the colored layer 29 and the liquid crystal thickness adjusting layer 22, and only the pixels 5 in which the liquid crystal 30 is transmissive are transmitted through the liquid crystal 30. Then, the light passing through the reflecting portion 7 is reflected by the reflecting plate 16. Reflected light from the reflecting plate 16 passes through the liquid crystal 30, the liquid crystal thickness adjusting layer 22, and the colored layer 29 and is emitted from the display surface of the liquid crystal display element 2. Incident light from the display surface and reflected light from the reflecting plate 16 are colored when passing through the colored layer 29 to color outgoing light.

  According to the present embodiment, since the liquid crystal adjustment layer and the colored layer are formed in separate steps, the man-hour is increased as compared with the first embodiment, but the material for forming the liquid crystal adjustment layer that has been used conventionally is used as it is as the liquid crystal adjustment layer. can do. Further, as in the case of the first embodiment, the interest of display can be increased and the visual effect can be improved, and the aesthetics can be improved by unifying the color arrangement of the device on which the liquid crystal display device 1 is mounted. In the present embodiment, one of the liquid crystal thickness adjusting layer 22 and the colored layer 29 may be provided on the counter substrate 20 side, and the other may be provided on the pixel substrate 10 side.

  Next, FIG. 4 shows a side sectional view of the liquid crystal display device of the third embodiment. For convenience of explanation, the same reference numerals are given to the same parts as those in the first embodiment shown in FIGS. In the present embodiment, unlike the first and second embodiments, an overcoat 32 that covers the color filter 21 is formed on the counter substrate 20. A liquid crystal thickness adjusting layer 22 is formed on the pixel substrate 10. Other parts are the same as those in the first embodiment.

  The overcoat 32 is made of a colorless translucent material and is formed across the transmission part 6 and the reflection part 7. The liquid crystal thickness adjusting layer 22 is formed on the reflecting plate 16 and contains a light color pigment. Thereby, the liquid crystal thickness adjusting layer 22 constitutes a colored layer that colors the transmitted light in a bluish color or a sepia color.

  When reflective display is performed with the backlight 3 turned off, light enters from the display surface of the liquid crystal display element 2. Incident light of the liquid crystal display element 2 passes through the liquid crystal 30 only in the pixels 5 in which the liquid crystal 30 is in a transmissive state. Then, the light passing through the reflecting portion 7 passes through the liquid crystal thickness adjusting layer 22 and is reflected by the reflecting plate 16. The reflected light of the reflecting plate 16 passes through the liquid crystal thickness adjusting layer 22 and the liquid crystal 30 and is emitted from the display surface of the liquid crystal display element 2. Incident light from the display surface and reflected light from the reflecting plate 16 are colored when passing through the liquid crystal thickness adjusting layer 22 to color outgoing light.

  Since switching elements and the like are formed on the pixel substrate 10, the pixel substrate 10 side has more manufacturing processes than the counter substrate 20 side, and it takes time to complete. For example, when manufacturing the pixel substrate 10 side and the counter substrate 20 side in the same factory, according to the present embodiment, the number of processes on the pixel substrate 10 side with many processes is further increased, and the completion of the pixel substrate 10 side and the counter substrate 20 are completed. This is not preferable because a wasteful time generated between the two sides is further increased.

  On the other hand, for example, when each of the pixel substrate 10 side and the counter substrate 20 side is manufactured at different locations, according to the present embodiment, the pixel substrate 10 side including the colored layer can be manufactured through a series of steps. For this reason, the influence of generation | occurrence | production of defects by coloring layer formation etc. does not generate | occur | produce on the counter substrate 20 side.

  Further, according to the present embodiment, as in the first embodiment, the display is more interesting and the visual effect can be improved, and the aesthetics are improved by unifying the color arrangement of the device on which the liquid crystal display device 1 is mounted. be able to.

  In the present embodiment, a color layer containing a pigment may be provided on the pixel substrate 10 in addition to the liquid crystal thickness adjusting layer 22 not containing a pigment, as in the second embodiment.

  The present invention can be used for a transflective liquid crystal display element and a liquid crystal display device having a reflective portion and a transmissive portion. Further, it can be used for a device using a transflective liquid crystal display device such as a cellular phone.

Side surface sectional drawing which shows the liquid crystal display device of 1st Embodiment of this invention. The top view which shows the pixel substrate of the liquid crystal display device of 1st Embodiment of this invention. Side surface sectional drawing which shows the liquid crystal display device of 2nd Embodiment of this invention. Side surface sectional drawing which shows the liquid crystal display device of 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 2 Liquid crystal display element 3 Backlight 5 Pixel 6 Transmission part 7 Reflection part 10 Pixel substrate 11 Gate line 12 Source line 15 Pixel electrode 16 Reflector 17, 24 Alignment film 20 Counter electrode 21 Color filter 22 Liquid crystal thickness adjustment layer (Colored layer)
23 Counter electrode 29 Colored layer 30 Liquid crystal 32 Overcoat

Claims (6)

  In a transflective liquid crystal display element in which liquid crystal is sealed between opposing substrates, and pixels in which a reflective portion and a transmissive portion are adjacent are arranged in a matrix, transmitted light is transmitted between adjacent pixels arranged in the transmissive portion. A liquid crystal display element comprising: a color filter for coloring in different colors; and a colored layer arranged in the reflecting portion and for coloring transmitted light in the same color in adjacent pixels.   2. The liquid crystal according to claim 1, wherein a liquid crystal thickness adjustment layer that makes the thickness of the liquid crystal of the reflection portion narrower than that of the transmission portion is provided in the reflection portion, and the colored layer is formed of the liquid crystal thickness adjustment layer. Display element.   The liquid crystal display element according to claim 2, wherein a pixel electrode provided for each pixel is formed on one of the substrates, and the color filter and the liquid crystal thickness adjusting layer are formed on the other substrate.   The liquid crystal display element according to claim 1, wherein the colored layer contains a light-colored pigment.   The liquid crystal display element according to claim 1, wherein the liquid crystal is in a light-shielding state when a voltage is applied between the substrates. A liquid crystal display device comprising: the liquid crystal display element according to claim 1; and a backlight disposed on a back surface of the liquid crystal display element.

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