JP2009122449A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device of which the color of the picture-frame section can be changed to a color other than black, and as a result the design can be diversified. <P>SOLUTION: The liquid crystal display device has an active area DSP to display an image and the picture-frame section FP to surround the active area, and is characterized in that it is equipped with: an array substrate AR equipped with pixel electrodes EP arranged on respective pixels of the active area, and reflection electrodes arranged on the picture-frame section; a counter substrate CT provided with a counter electrode ET arranged on the active area and the picture-frame section; a liquid crystal layer LQ held between the array substrate and the counter substrate; and a retardation setting portion RTD to set the retardation of the liquid crystal layer with the potential difference between the reflection electrode and the counter electrode so as to bring about a reflection display with a predetermined color resulting from light incident from the counter substrate side in the picture-frame section. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device configured such that a frame portion reflects and displays a desired color.

  Liquid crystal display devices are widely used as displays for OA equipment, portable information terminals, and the like because they are thin, light, and have low power consumption. In particular, an active matrix liquid crystal display device in which a switching element is arranged for each pixel has excellent display characteristics, and is becoming a mainstream display device, and research and development have been actively conducted.

In such a liquid crystal display device, the frame portion around the active area for displaying an image is usually black. In other words, in addition to the technology of placing a black colored resin or metal in the frame portion to shield the light, a voltage that causes a black display on the liquid crystal layer between the transparent display electrode and the frame electrode by arranging a frame electrode in the frame portion Is disclosed (for example, see Patent Document 1).
Japanese Patent Laid-Open No. 11-101991

  In a normal liquid crystal display device, the frame portion is black and has a uniform design. On the other hand, it is expected that a liquid crystal display device in which the frame portion can be changed to a color other than black in accordance with the color of the housing or the user's preference is expected.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a liquid crystal display device in which the frame portion can be changed to a color other than black and the design can be diversified. It is in.

The liquid crystal display device according to the first aspect of the present invention comprises:
A liquid crystal display device having an active area for displaying an image and a frame portion surrounding the active area,
A first substrate comprising: a pixel electrode disposed in each pixel of the active area; and a reflective electrode disposed in the frame portion;
A second substrate provided with a counter electrode disposed in the active area and the frame portion;
A liquid crystal layer held between the first substrate and the second substrate;
A retardation setting unit that sets a retardation of the liquid crystal layer according to a potential difference between the reflective electrode and the counter electrode so that a reflective display of a predetermined color by light incident from the second substrate side in the frame portion; ,
It is provided with.

A liquid crystal display device according to a second aspect of the present invention provides:
A liquid crystal display device having an active area for displaying an image and a frame portion surrounding the active area,
A first substrate comprising: a pixel electrode disposed in each pixel of the active area; and a reflector disposed in the frame portion;
A second substrate having a counter electrode disposed in the active area;
A liquid crystal layer held between the first substrate and the second substrate;
A birefringent medium layer disposed on the frame portion,
The sum total of the retardation of the birefringent medium layer and the retardation of the liquid crystal layer in the frame portion is set so as to be a reflection display of a predetermined color by light incident from the second substrate side in the frame portion. It is characterized by that.

  According to the present invention, it is possible to provide a liquid crystal display device in which the frame portion can be changed to a color other than black and the design can be diversified.

  A liquid crystal display device according to an embodiment of the present invention will be described below with reference to the drawings. Here, a transflective liquid crystal display device in which each pixel has a reflective display unit that displays an image using external light and a transmissive display unit that displays an image using backlight is described as an example. The present invention is not limited to this example. For example, the present invention can be applied to various types of liquid crystal display devices such as a transmissive liquid crystal display device in which each pixel has only a transmissive display portion and a reflective liquid crystal display device in which each pixel has a reflective display portion. Since the structure of the frame portion is similar to that of the reflective display portion, the present invention is preferably applied to a transflective or reflective liquid crystal display device in which each pixel has at least a reflective display portion in consideration of manufacturing yield. .

<< First Embodiment >>
As shown in FIGS. 1 and 2, the liquid crystal display device is a normally white type transflective color liquid crystal display device using birefringence, and includes a liquid crystal display panel LPN. The liquid crystal display panel LPN includes an array substrate (first substrate) AR, a counter substrate (second substrate) CT arranged opposite to the array substrate AR, and between the array substrate AR and the counter substrate CT. The liquid crystal layer LQ that is held is provided.

  Further, the liquid crystal display device includes a first optical element OD1 provided on one outer surface of the liquid crystal display panel LPN (that is, the outer surface opposite to the surface holding the liquid crystal layer LQ of the array substrate AR), and the liquid crystal display panel. A second optical element OD2 provided on the other outer surface of the LPN (that is, the outer surface opposite to the surface holding the liquid crystal layer LQ of the counter substrate CT) is provided. Further, the liquid crystal display device having the transmissive display unit as described above includes a backlight unit BL that illuminates the liquid crystal display panel LPN from the first optical element OD1 side.

  Such a liquid crystal display device includes m × n pixels PX arranged in a matrix in an active area DSP that displays an image. Each pixel PX includes a reflective display portion PR that displays an image by selectively reflecting external light, and a transmissive display portion PT that displays an image by selectively transmitting backlight light from the backlight unit BL. And have.

  The array substrate AR is formed using an insulating substrate 10 having optical transparency such as a glass plate. That is, the array substrate AR includes m × n pixel electrodes EP arranged for each pixel in the active area DSP, and n scanning lines Y () formed along the row direction of these pixel electrodes EP. Y1 to Yn), m signal lines X (X1 to Xm) respectively formed along the column direction of the pixel electrodes EP, and in the vicinity of the intersection of the scanning line Y and the signal line X in each pixel PX. There are provided m × n switching elements W and the like.

  The array substrate AR is further connected to at least a part of the scanning line driver YD connected to the n scanning lines Y and the m signal lines X in the driving circuit region DCT around the active area DSP. At least a part of the signal line driver XD. The scanning line driver YD sequentially supplies scanning signals to the n scanning lines Y based on control by the controller CNT. Further, the signal line driver XD supplies a video signal to the m signal lines X at a timing when the switching elements W in each row are turned on by the scanning signal based on the control by the controller CNT. Thereby, the pixel electrode EP of each row is set to a pixel potential corresponding to the video signal supplied via the corresponding switching element W.

  Each switching element W is, for example, an N-channel thin film transistor, and includes a semiconductor layer 12 disposed on the insulating substrate 10. The semiconductor layer 12 can be formed of, for example, polysilicon or amorphous silicon, and is formed of polysilicon here. The semiconductor layer 12 has a source region 12S and a drain region 12D on both sides of the channel region 12C. The semiconductor layer 12 is covered with a gate insulating film 14.

  The gate electrode WG of the switching element W is connected to one scanning line Y (or formed integrally with the scanning line Y), and is disposed on the gate insulating film 14 together with the scanning line Y. These gate electrodes WG and scanning lines Y are covered with an interlayer insulating film 16. The source electrode WS and the drain electrode WD of the switching element W are disposed on both sides of the gate electrode WG on the interlayer insulating film 16. The source electrode WS is connected to one signal line X (or formed integrally with the signal line X) and is in contact with the source region 12S of the semiconductor layer 12. The drain electrode WD is connected to one pixel electrode EP (or formed integrally with the pixel electrode EP) and is in contact with the drain region 12D of the semiconductor layer 12. These source electrode WS, drain electrode WD, and signal line X are covered with an organic insulating film 18.

  The pixel electrode EP has a reflective pixel electrode EPR provided corresponding to the reflective display part PR and a transmissive pixel electrode EPT provided corresponding to the transmissive display part PT. The reflective pixel electrode EPR is disposed on the organic insulating film 18 and is formed of a conductive material having light reflectivity such as aluminum. The transmissive pixel electrode EPT is disposed on the interlayer insulating film 16 and is formed of a light-transmitting conductive material such as indium tin oxide (ITO). These reflective pixel electrode EPR and transmissive pixel electrode EPT are electrically connected to the drain electrode WD. The surface of the array substrate AR that contacts the liquid crystal layer LQ is covered with the alignment film 20.

  On the other hand, the counter substrate CT is formed using an insulating substrate 30 having optical transparency such as a glass plate. That is, the counter substrate CT includes, in the active area DSP, a black matrix 32 that partitions each pixel PX, a color filter 34 disposed in each pixel PX surrounded by the black matrix 32, a counter electrode ET, and the like.

  The black matrix 32 is disposed so as to face wiring portions such as the scanning lines Y, the signal lines X, and the switching elements W provided on the array substrate AR. The color filter 34 is formed of a plurality of different colors, for example, colored resins colored in three primary colors such as red, blue, and green. The red colored resin, the blue colored resin, and the green colored resin are disposed corresponding to the red pixel, the blue pixel, and the green pixel, respectively.

  The color filter 34 may be formed so that the optical density is different between the reflective display portion PR and the transmissive display portion PT. That is, in the reflective display portion PR, external light contributing to display passes through the color filter 34 twice, whereas in the transmissive display portion PT, backlight light contributing to display passes through the color filter 34 once. Only. Therefore, in order to adjust the color tone between the reflective display part PR and the transmissive display part PT, the optical density of the colored resin arranged in the reflective display part PR is set to about half that of the colored resin arranged in the transmissive display part PT. Alternatively, a non-colored resin may be disposed in a part of the reflective display portion PR.

  The counter electrode ET is disposed so as to face the pixel electrodes EP of all the pixels PX. The counter electrode ET is a transmissive electrode formed of a light-transmitting conductive material such as indium tin oxide (ITO). The counter electrode ET is electrically connected to, for example, a common potential terminal COM. The surface of the counter substrate CT that contacts the liquid crystal layer LQ is covered with the alignment film 36.

  When the counter substrate CT and the array substrate AR as described above are arranged so that the alignment films 20 and 36 face each other, a predetermined gap is formed by a spacer (not shown) arranged therebetween. The At this time, a gap of about half of the transmissive display part PT is formed in the reflective display part PR.

  The liquid crystal layer LQ is composed of a liquid crystal composition including liquid crystal molecules 40 enclosed in a gap formed between the alignment film 20 of the array substrate AR and the alignment film 36 of the counter substrate CT. In this embodiment, the liquid crystal layer LQ includes liquid crystal molecules 40 having a twist angle of 0 deg (homogeneous alignment).

  Each of the first optical element OD1 and the second optical element OD2 includes a polarizing plate and one or more retardation plates, and controls the polarization state of light that has passed through these. In the first embodiment, the polarizing plate of the first optical element OD1 is arranged so that the absorption axis thereof is orthogonal to the absorption axis of the polarizing plate of the second optical element OD2, thereby realizing normally white.

  By the way, in the liquid crystal display device according to the first embodiment, the frame-shaped frame portion FP surrounding the active area DSP is configured to be capable of reflective display in various colors.

  That is, the array substrate AR includes the reflective electrode FR disposed on the frame portion FP. The reflective electrode FR is disposed on the organic insulating film 18. The reflective electrode FR can be formed of the same material as the reflective pixel electrode EPR of each pixel PX, and is preferably formed in the same process.

  The counter electrode ET is disposed not only in the active area DSP but also in the frame portion FP. The counter electrode ET may be integrally formed over the active area DSP and the frame portion FP, or is divided into a segment formed in the active area DSP and a segment formed in the frame portion FP. May be configured to be electrically connected.

  Also in such a frame portion FP, the surfaces of the reflective electrode FR and the counter electrode ET are covered with the alignment film 20 and the alignment film 36, respectively. That is, in the frame portion FP, the liquid crystal layer LQ is held between the reflective electrode FR and the counter electrode ET. A frame-shaped light shielding layer BM is disposed around the frame portion FP.

  In such a frame portion FP, light incident from the counter substrate CT side via the second optical element OD2 passes through the liquid crystal layer LQ, is reflected by the reflective electrode FR, passes through the liquid crystal layer LQ again, and passes through the second optical element. It reaches the element OD2. At this time, the light passing through the liquid crystal layer LQ is affected by the retardation of the liquid crystal layer LQ. The wavelength of light that can be transmitted through the second optical element OD2 is determined depending on the retardation of the liquid crystal layer LQ. In other words, when the retardation of the liquid crystal layer LQ is a certain value R, the light that can be transmitted through the second optical element OD2, that is, the reflected light from the reflective electrode FR exhibits a certain wavelength dispersion characteristic. Due to such chromatic dispersion characteristics, the frame portion FP is visually recognized as being reflected and displayed in a certain color.

  The retardation of the liquid crystal layer LQ is given by the product (Δn · d) of the birefringence (Δn) of the liquid crystal layer LQ and the thickness of the liquid crystal layer LQ, that is, the cell gap (d). For this reason, it is possible to change the retardation of the liquid crystal layer LQ by changing the birefringence of the liquid crystal layer LQ.

  In the first embodiment, by using such a phenomenon, the birefringence of the liquid crystal layer LQ is changed by a potential difference between the reflective electrode FR and the counter electrode ET in the frame portion FP, thereby obtaining a predetermined value. The retardation of the liquid crystal layer LQ is set so as to obtain the reflective display of the color. More specifically, the liquid crystal display device includes a retardation setting unit RTD as shown in FIG. The retardation setting unit RTD is connected to the reflective electrode FR, and applies a voltage to the reflective electrode FR so as to form a predetermined potential difference with respect to the potential of the counter electrode ET (eg, common potential) based on control by the controller CNT. To do.

  For example, when the cell gap d in the frame portion FP is 5 μm, when the potential difference between the reflective electrode FR and the counter electrode ET is set to 1.0 V, the retardation Δn · d of the liquid crystal layer LQ is 350 nm. At this time, the wavelength dispersion characteristic of the reflected light at the frame portion FP becomes a characteristic as indicated by “A” in FIG. 3, and a blue reflective display is obtained as indicated by “A” in FIG.

  Similarly, when the potential difference between the reflective electrode FR and the counter electrode ET is set to 1.5 V, the retardation Δn · d of the liquid crystal layer LQ is 290 nm. At this time, the wavelength dispersion characteristic of the reflected light at the frame portion FP becomes a characteristic as indicated by “B” in FIG. 3, and a purple reflection display is obtained as indicated by “B” in FIG.

  Similarly, when the potential difference between the reflective electrode FR and the counter electrode ET is set to 1.6 V, the retardation Δn · d of the liquid crystal layer LQ is 275 nm. At this time, the wavelength dispersion characteristic of the reflected light at the frame portion FP becomes a characteristic indicated by “C” in FIG. 3, and an orange reflective display is obtained as indicated by “C” in FIG.

  Similarly, when the potential difference between the reflective electrode FR and the counter electrode ET is set to 1.8 V, the retardation Δn · d of the liquid crystal layer LQ is 245 nm. At this time, the wavelength dispersion characteristic of the reflected light at the frame portion FP becomes a characteristic as indicated by “D” in FIG. 3, and a yellow reflective display is obtained as indicated by “D” in FIG.

  Similarly, when the potential difference between the reflective electrode FR and the counter electrode ET is set to 2.3 V, the retardation Δn · d of the liquid crystal layer LQ is 180 nm. At this time, the wavelength dispersion characteristic of the reflected light at the frame portion FP becomes a characteristic as indicated by “E” in FIG. 3, and a white reflective display is obtained as indicated by “E” in FIG.

  Similarly, when the potential difference between the reflective electrode FR and the counter electrode ET is set to 3.2 V, the retardation Δn · d of the liquid crystal layer LQ is 105 nm. At this time, the wavelength dispersion characteristic of the reflected light at the frame portion FP becomes a characteristic as indicated by “F” in FIG. 3, and a gray reflection display is obtained as indicated by “F” in FIG.

  Similarly, when the potential difference between the reflective electrode FR and the counter electrode ET is set to 5.0 V, the retardation Δn · d of the liquid crystal layer LQ is 60 nm. At this time, the wavelength dispersion characteristic of the reflected light at the frame portion FP becomes a characteristic indicated by “G” in FIG. 3, and the reflectance is substantially zero for almost all wavelengths. For this reason, the frame portion FP is black as shown by “G” in FIG. 4. In this frame portion FP, since the reflective electrode FR is disposed, the backlight light is shielded, so that it is black if there is no external light, that is, incident light from the counter substrate CT side.

  According to the first embodiment, the retardation of the liquid crystal layer LQ in the frame portion FP is set by the potential difference between the reflective electrode FR and the counter electrode ET so that the frame portion FP has a predetermined color reflection display. It is configured to do. That is, the color of the frame portion FP can be changed by the retardation of the liquid crystal layer LQ, and a liquid crystal display device having a frame portion of a color other than black can be provided. As a result, it is possible to change the color of the frame portion in accordance with the color of the casing, or to change the color of the frame portion in accordance with the user's preference, thereby enabling diversification of the design.

  The cell gap d (FP) of the frame portion FP is desirably set to be larger than the cell gap d (PR) of the reflective display portion PR in the active area DSP. More preferably, the cell gap d (FP) is set to 2 to 3 times the cell gap d (PR). Thereby, the range which can set the retardation of liquid crystal layer LQ can be expanded, and the width | variety selectable as a reflective display color of the frame part FP can also be expanded.

  The upper limit of the retardation of the liquid crystal layer LQ is preferably about 300 nm to 400 nm. As a result, blue can be selected as the reflective display color of the frame portion FP. The lower limit of the retardation of the liquid crystal layer LQ is preferably about 50 nm to 100 nm. Thereby, general black can be selected as a reflective display color of the frame part FP.

  For example, when the cell gap d (FP) is 5 μm and the cell gap d (PR) is 2 μm, the cell gap d (FP) is 2.5 times the cell gap d (PR), and the liquid crystal layer The retardation of LQ can be set in a range of 350 nm (when the potential difference is zero V) to 60 nm (when the potential difference is 5 V). At this time, as the reflection display color of the frame portion FP, blue, purple, orange, yellow, white, gray, and black can be selected as in the example shown in FIG.

<< Second Embodiment >>
The liquid crystal display device according to the second embodiment is also a normally white type transflective color liquid crystal display device using birefringence, and includes a liquid crystal display panel LPN having the same active area configuration as that of the first embodiment. ing. The liquid crystal display device according to the second embodiment is configured such that the frame portion FP can be reflected and displayed in a predetermined color.

  That is, the array substrate AR includes a reflector FRP disposed in the frame part FP. The reflecting plate FRP is disposed on the organic insulating film 18. The reflective plate FRP can be formed of the same material as the reflective pixel electrode EPR of each pixel PX, and is preferably formed in the same process. The counter electrode ET is disposed at least in the active area DSP and may extend to the frame portion FP.

  Further, in the second embodiment, the liquid crystal display panel LPN includes a birefringent medium layer BR disposed in the frame portion FP. The birefringent medium layer BR is disposed between the reflecting plate FRP and the second optical element OD2. In the example shown in FIG. 6, the birefringent medium layer BR is disposed on the inner surface of the counter substrate CT. The birefringent medium layer BR having such a configuration is called an in-cell retarder, and can be formed by, for example, patterning a liquid crystal polymer.

  Also in such a frame portion FP, the surfaces of the array substrate AR and the counter substrate CT are covered with the alignment film 20 and the alignment film 36, respectively, and the liquid crystal layer LQ is held between these alignment films. A frame-shaped light shielding layer BM is disposed around the frame portion FP.

  In such a frame portion FP, the light incident from the counter substrate CT side via the second optical element OD2 passes through the birefringent medium layer BR and the liquid crystal layer LQ, is reflected by the reflecting plate FRP, and again returns to the liquid crystal layer LQ. And the birefringent medium layer BR and the second optical element OD2. At this time, the light passing through the birefringent medium layer BR and the liquid crystal layer LQ is affected by the retardation of the birefringent medium layer BR and the liquid crystal layer LQ. The wavelength of light that can be transmitted through the second optical element OD2 is determined depending on the retardation of the birefringent medium layer BR and the liquid crystal layer LQ. In other words, when the sum of the retardations of the birefringent medium layer BR and the liquid crystal layer LQ is a certain value R, the light that can be transmitted through the second optical element OD2, that is, the reflected light from the reflective electrode FR has a certain wavelength dispersion characteristic. Presents. Due to such chromatic dispersion characteristics, the frame portion FP is visually recognized as being reflected and displayed in a certain color.

  The retardation of the birefringent medium layer BR can be changed depending on the thickness, birefringence of the material, and the like. Further, the retardation of the liquid crystal layer LQ can be changed by the birefringence of the liquid crystal material and the thickness of the liquid crystal layer LQ (cell gap of the frame portion). The birefringence of the liquid crystal material is determined with priority given to realizing the display performance required in the active area DSP, so that the retardation of the liquid crystal layer LQ in the frame portion FP is controlled by the cell gap of the frame portion FP. For example, it is set to 140 nm to 160 nm.

  At this time, when the slow axis of the birefringent medium layer BR and the director of the liquid crystal molecules 40 included in the liquid crystal layer LQ are set in a substantially parallel orientation, the retardation R (BR) of the birefringent medium layer BR is set. And the retardation R (LQ) of the liquid crystal layer LQ is given by (R (BR) + R (LQ)).

  In addition, when the slow axis of the birefringent medium layer BR and the director of the liquid crystal molecules 40 included in the liquid crystal layer LQ are set to be substantially perpendicular to each other, the retardation R (BR) of the birefringent medium layer BR and The sum total with the retardation R (LQ) of the liquid crystal layer LQ is given by (R (BR) -R (LQ)).

  In any case, in the second embodiment, by utilizing such a phenomenon, the sum of retardations of the birefringent medium layer BR and the liquid crystal layer LQ so as to provide a reflection display of a predetermined color in the frame portion FP. Set.

  For example, when the retardation of the liquid crystal layer LQ in the frame portion FP is 155 nm and the retardation of the birefringent medium layer BR is 0 nm (in this case, the birefringent medium layer BR does not exist), The wavelength dispersion characteristic of the reflected light is a characteristic indicated by “W” in FIG. 7, and the frame portion FP becomes a white reflective display.

  When the director of the liquid crystal molecules 40 included in the liquid crystal layer LQ and the slow axis of the birefringent medium layer BR are set in a substantially parallel orientation, the retardation of the liquid crystal layer LQ in the frame portion FP is the above value. When the retardation of the birefringent medium layer BR is +50 nm, the total retardation of the birefringent medium layer BR and the liquid crystal layer LQ is 205 nm. At this time, the wavelength dispersion characteristic of the reflected light at the frame portion FP becomes a characteristic as indicated by “A” in FIG. 7, and a yellow reflective display is obtained as indicated by “A” in FIG.

  Similarly, when the retardation of the birefringent medium layer BR is +100 nm, the total retardation of the birefringent medium layer BR and the liquid crystal layer LQ is 255 nm. At this time, the wavelength dispersion characteristic of the reflected light at the frame portion FP becomes a characteristic as indicated by “B” in FIG. 7, and an orange reflective display is obtained as indicated by “B” in FIG.

  Similarly, when the retardation of the birefringent medium layer BR is +125 nm, the total retardation of the birefringent medium layer BR and the liquid crystal layer LQ is 280 nm. At this time, the wavelength dispersion characteristic of the reflected light at the frame portion FP becomes a characteristic as indicated by “C” in FIG. 7, and a pink color reflection display is obtained as indicated by “C” in FIG.

  Similarly, when the retardation of the birefringent medium layer BR is +150 nm, the total retardation of the birefringent medium layer BR and the liquid crystal layer LQ is 305 nm. At this time, the wavelength dispersion characteristic of the reflected light at the frame portion FP becomes a characteristic as indicated by “D” in FIG. 7, and a purple reflection display is obtained as indicated by “D” in FIG.

  Similarly, when the retardation of the birefringent medium layer BR is +175 nm, the total retardation of the birefringent medium layer BR and the liquid crystal layer LQ is 330 nm. At this time, the wavelength dispersion characteristic of the reflected light at the frame portion FP becomes a characteristic as indicated by “E” in FIG. 7, and a blue reflective display is obtained as indicated by “E” in FIG.

  Similarly, when the retardation of the birefringent medium layer BR is +225 nm, the total retardation of the birefringent medium layer BR and the liquid crystal layer LQ is 380 nm. At this time, the wavelength dispersion characteristic of the reflected light at the frame portion FP becomes a characteristic as indicated by “F” in FIG. 7, and a cyan reflective display is obtained as indicated by “F” in FIG.

  On the other hand, when the director of the liquid crystal molecules 40 included in the liquid crystal layer LQ and the slow axis of the birefringent medium layer BR are set to be substantially perpendicular to each other, the retardation of the liquid crystal layer LQ in the frame portion FP is the above value. When the retardation of the birefringent medium layer BR is −125 nm, the total retardation of the birefringent medium layer BR and the liquid crystal layer LQ is 30 nm. At this time, the wavelength dispersion characteristic of the reflected light at the frame portion FP becomes a characteristic as indicated by “Bk” in FIG. 7, and the reflectance is almost zero for almost all wavelengths. For this reason, the frame part FP is black.

  Similarly, when the retardation of the birefringent medium layer BR is −175 nm, the total retardation of the birefringent medium layer BR and the liquid crystal layer LQ is −20 nm. At this time, the wavelength dispersion characteristic of the reflected light at the frame portion FP becomes a characteristic indicated by “G” in FIG. 7, and the frame portion FP is displayed in gray.

  According to the first embodiment, the retardation of the liquid crystal layer LQ and the birefringent medium layer BR in the frame portion FP is set so that the frame portion FP has a predetermined color reflection display. That is, the color of the frame portion FP includes the orientation relationship between the director of the liquid crystal molecules contained in the liquid crystal layer LQ and the slow axis of the birefringent medium layer BR, the retardation of the liquid crystal layer LQ, and the retardation of the birefringent medium layer BR. The liquid crystal display device having a frame portion of a color other than black can be provided. As a result, it is possible to set the color of the frame portion in accordance with the color and specifications of the housing, and the design can be diversified.

  The retardation of the birefringent medium layer BR is preferably set in the range of 0 nm to 250 nm. Thereby, the width | variety which can be selected as a reflective display color of the frame part FP can be expanded.

  That is, when the director of the liquid crystal layer LQ and the slow axis of the birefringent medium layer BR are set in parallel, the frame can be obtained by applying the birefringent medium layer BR having any retardation in the above range. As the reflection display color of the part FP, yellow ⇒ orange ⇒ pink ⇒ purple ⇒ blue ⇒ cyan can be selected as in the example shown in FIG. 8. In addition, when the director of the liquid crystal layer LQ and the slow axis of the birefringent medium layer BR are set to be orthogonal to each other, black → gray can be selected as the reflective display color of the frame portion FP.

  In addition, this invention is not limited to the said embodiment itself, In the stage of implementation, it can change and implement a component within the range which does not deviate from the summary. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

  For example, in the first embodiment and the second embodiment described above, a normally white type transflective color liquid crystal display device has been described as an example. However, the present invention can also be applied to a normally black type liquid crystal display device. In addition, the liquid crystal display device to which the present invention can be applied is not limited to the transflective type.

FIG. 1 is a diagram schematically showing a configuration of a liquid crystal display device according to a first embodiment of the present invention. FIG. 2 is a diagram schematically showing a cross-sectional structure of the liquid crystal display device shown in FIG. FIG. 3 is a diagram showing the wavelength dispersion characteristics of the reflected light in the frame portion of the liquid crystal display device shown in FIG. FIG. 4 is a diagram showing chromaticity coordinates corresponding to the color of reflected light having the wavelength dispersion characteristic shown in FIG. FIG. 5 is a diagram schematically showing a configuration of a liquid crystal display device according to the second embodiment of the present invention. FIG. 6 schematically shows a cross-sectional structure of the liquid crystal display device shown in FIG. FIG. 7 is a diagram showing the wavelength dispersion characteristics of the reflected light in the frame portion of the liquid crystal display device shown in FIG. FIG. 8 is a diagram showing chromaticity coordinates corresponding to the color of the reflected light having the wavelength dispersion characteristic shown in FIG.

Explanation of symbols

LPN ... Liquid crystal display panel AR ... Array substrate CT ... Counter substrate LQ ... Liquid crystal layer BL ... Backlight unit OD1 ... First optical element OD2 ... Second optical element DSP ... Active area PX ... Pixel PR ... Reflective display unit PT ... Transmission display Part FP ... Frame part FR ... Reflective electrode RTD ... Retardation setting part FRP ... Reflector plate BR ... Birefringent medium layer

Claims (8)

A liquid crystal display device having an active area for displaying an image and a frame portion surrounding the active area,
A first substrate comprising: a pixel electrode disposed in each pixel of the active area; and a reflective electrode disposed in the frame portion;
A second substrate provided with a counter electrode disposed in the active area and the frame portion;
A liquid crystal layer held between the first substrate and the second substrate;
A retardation setting unit that sets a retardation of the liquid crystal layer according to a potential difference between the reflective electrode and the counter electrode so that a reflective display of a predetermined color by light incident from the second substrate side in the frame portion; ,
A liquid crystal display device comprising: The pixel has at least a reflective display portion,
The liquid crystal display device according to claim 1, wherein the frame portion has a larger cell gap than the reflective display portion in the active area.   The liquid crystal display device according to claim 2, wherein the retardation of the liquid crystal layer is set in a range of 50 nm to 400 nm. A liquid crystal display device having an active area for displaying an image and a frame portion surrounding the active area,
A first substrate comprising: a pixel electrode disposed in each pixel of the active area; and a reflector disposed in the frame portion;
A second substrate having a counter electrode disposed in the active area;
A liquid crystal layer held between the first substrate and the second substrate;
A birefringent medium layer disposed on the frame portion,
The sum total of the retardation of the birefringent medium layer and the retardation of the liquid crystal layer in the frame portion is set so as to be a reflection display of a predetermined color by light incident from the second substrate side in the frame portion. A liquid crystal display device characterized by the above.   The liquid crystal display device according to claim 4, wherein the birefringent medium layer is disposed on an inner surface of the second substrate.   5. The liquid crystal display device according to claim 4, wherein the slow axis of the birefringent medium layer is set in a direction substantially parallel to a director of liquid crystal molecules included in the liquid crystal layer in the frame portion.   5. The liquid crystal display device according to claim 4, wherein a slow axis of the birefringent medium layer is set in an orientation substantially orthogonal to a director of liquid crystal molecules included in the liquid crystal layer in the frame portion.   The liquid crystal display device according to claim 6, wherein the retardation of the birefringent medium layer is set in a range of 0 nm to 250 nm.

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