JP2000267077A - Liquid crystal display and electronic equipment - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve display quality, particularly color reproducibility, in a transflective / semi-reflective liquid crystal panel during transmission. SOLUTION: In a liquid crystal panel 100 in which a liquid crystal is sandwiched between a front substrate 200 and a rear substrate 300 and a reflection layer 332 provided with a slit 335 is formed in the rear substrate 300, a first color filter 322 is provided. , Second
And the color filter 324 are arranged and formed with the reflection layer 332 interposed therebetween. As a result, the transmitted light also passes through the color filter twice, similarly to the reflected light.
The color reproducibility of both lights becomes almost equal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device which functions as a reflection type in the presence of external light but functions as a transmission type in the case where there is almost no external light. Electronic devices.

[0002]

2. Description of the Related Art As is well known, in a liquid crystal display device, a liquid crystal itself does not emit light, but displays an image simply by changing a light path. For this reason, the liquid crystal display device needs to have a configuration in which light is always incident on the panel in some form. In this respect, display devices using other methods, such as an electroluminescence display device and a plasma display, are required. This is a big difference. Here, in the liquid crystal display device, a type in which a light source is arranged on the back side of the panel and the light passes through the panel and is visible to the user is called a transmission type, while the light source is arranged or arranged on the front side of the panel. A type in which incident light from the front surface is reflected by a panel and visually recognized by a user without being viewed is called a reflection type.

In the transmission type, light emitted from a light source (henceforth called a backlight) disposed on the back side of the panel is guided to the entire panel by a light guide plate, and then, generally, a polarizing plate is used. Back substrate → electrode → liquid crystal → electrode →
The user can visually recognize the color filter, the front substrate, and the polarizing plate. On the other hand, in the reflection type, the light incident on the panel generally reaches the polarizing plate → front substrate → color filter → electrode → liquid crystal → reflection electrode.
The light is reflected by the reflective electrode, and is visually recognized by the user following the path that has just come. As described above, in the reflection type, compared with the transmission type, the amount of light from the environment is not as large as that of the light source arranged on the back side of the panel, and furthermore, a double path in which light enters the panel and is reflected. Therefore, the amount of light that is visually recognized by the user is reduced by the light attenuation in each unit. For this reason, the reflective type has a disadvantage that the display screen is generally darker than the transmissive type.

[0004] However, the reflection type has many advantages over the above-mentioned disadvantages, such as the fact that display is possible without a light source with large power consumption and that the visibility is high even outdoors where sunlight is applied. For this reason, in recent years, reflective liquid crystal display devices capable of performing color display have begun to spread gradually, mainly in portable electronic devices and the like.

[0005] The reflection type has an essential problem that the display cannot be visually recognized by the user when there is almost no external light. In order to solve this, first, a slit is provided in the reflective electrode, or the reflective electrode is made relatively thin (for example, 20 nm to 50 nm) by using a metal having light reflectivity, such as aluminum. A method of providing a backlight on the back of a panel (semi-transmissive / semi-reflective panel) has been proposed. In this system, when there is almost no external light, the backlight turns on to make it transmissive, which ensures the visibility of the display. On the other hand, when there is enough external light, it turns off the backlight to turn off the light. And thus, a configuration in which low power consumption is achieved. That is, according to the intensity of external light, a transmission type or a reflection type, or a combination of both, is used to ensure both visibility and low power consumption.

[0006]

However, in a semi-transmissive / semi-reflective panel, transmitted light that is visually recognized by a user when functioning as a transmissive type has passed through a color filter only once. The reflected light that is visually recognized by the user when functioning as a reflection type is a color filter having two colors.
Since the light passes through once, the density of the transmitted light is lower than that of the reflected light. Therefore, if the color characteristics of the color filter are increased to solve this drawback, the brightness at the time of reflection is reduced. That is, in the conventional transflective / semi-reflective panel, it is necessary to give priority to either the transmissive type or the reflective type color reproducibility, and the other color reproducibility is inevitably deteriorated. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to improve the color reproducibility of a semi-transmissive / semi-reflective panel when functioning as a transmissive panel, and a reflective type panel. An object of the present invention is to provide a liquid crystal display device in which color reproducibility can be arbitrarily set when functioning as a device, and achieve both color reproducibility in both types, and an electronic device using the liquid crystal display device.

[0008]

According to the present invention, there is provided a liquid crystal display device comprising a front substrate and a rear substrate, wherein a liquid crystal is sandwiched between the front substrate and the rear substrate. A reflection layer formed on the back substrate and reflecting incident light from the front substrate side, and transmitting at least a part of the incident light from the back substrate side, with respect to the reflection layer, closer to the front substrate. It is characterized by comprising a first color filter provided, and a second color filter for coloring light passing through the slit among incident light from the rear substrate side.

According to the present invention, when functioning as a reflection type, the reflected light from the reflective layer is visually recognized by the user, and this reflected light is incident from the front substrate side and transmitted through the first color filter. Since the light is reflected by the reflection layer and passes through the first color filter again, the light passes through the first color filter twice. For this reason, the color reproducibility in the reflection type is determined only by the first color filter. On the other hand, when functioning as a transmission type, the light transmitted through the reflective layer is visually recognized by the user.
Each pass once.
For this reason, the color reproducibility in the transmission type is the first and the second.
Are determined by both the color filters.

Therefore, by separately setting the color characteristics of the first and second color filters, the color reproducibility of the reflective type and the transmissive type can be individually optimized, and the color reproducibility of the reflective type and the transmissive type can be set to different values. It is possible to do. Therefore, the color reproducibility of the transmissive type can be made comparable to that of a panel using only the normal transmissive type, and the color reproducibility of the reflective type and the transmissive type can be made substantially equal.

Here, in the present invention, in order to transmit at least a part of the incident light from the back substrate side, first, a configuration in which a slit is provided in the reflective layer may be considered. With this configuration, light can surely pass through the reflective layer regardless of the thickness and properties of the reflective layer.

In the present invention, in order to transmit at least a part of incident light from the rear substrate side, the reflective layer is formed of a light-reflective metal film having a thickness of 20 nm to 50 nm. The following configuration is conceivable. In this configuration, it is not necessary to form a slit, so that manufacturing can be simplified.

On the other hand, in the present invention, it is preferable that the coloring by the second color filter and the coloring by the first color filter are substantially the same color. According to this, the coloring of the transmitted light in the transmission type is prevented from becoming thinner than the coloring of the reflected light in the reflection type.

Further, in the present invention, it is preferable that a light source for irradiating light incident on the rear substrate side and emitted from the front substrate side is provided. According to this configuration, even when external light is small, the irradiation light of the light source passes through the slit and rotates in accordance with the alignment direction of the liquid crystal molecules. It is possible to secure. At this time, only the irradiation light of the light source passing through the slit passes through the second color filter. Therefore, by setting the color characteristics of the second color filter according to the spectral characteristics of the irradiation light, etc. It is also possible to optimize the color characteristics in the mold.

On the other hand, in the present invention, it is desirable to have a pixel electrode and a switching element arranged corresponding to intersections of a plurality of scanning lines and a plurality of data lines. According to this, since the ON pixel and the OFF pixel can be electrically separated by the switching element, the contrast, the response, and the like are good, and a high-definition display can be easily achieved.

At this time, the pixel electrode and the switching element are provided on the front substrate, respectively.
It is preferable that the first color filter is provided on the back substrate together with the second color filter.
According to this configuration, the switching elements requiring high accuracy are formed on the reflection layer and the front substrate different from the rear substrate on which the first and second color filters are formed. It is not necessary to consider the heat resistance and the like. For this reason, the degree of freedom of the manufacturing method of the switching element can be increased.

It is preferable that the pixel electrode and the switching element are respectively provided on the back substrate. In this configuration, the switching element requiring high precision is formed on the rear substrate side on which the reflective layer is formed. However, by devising the arrangement of the color filters, the process can be shared.

For example, the reflective layer and the pixel electrode
When the same conductive layer having light reflectivity is patterned, the process is simplified as compared with the case where the reflective layer and the pixel electrode are formed of different metal layers. Further, a thin film diode having a structure of a first conductive layer / insulator / second conductive layer is used as a switching element, and a reflection layer is formed by the second conductive layer to form a second conductive layer.
The reflection layer and the pixel electrode may be shared.

On the other hand, the second color filter need only be provided in the slit portion if it is sufficient to color the light passing through the slit. Therefore, it is not necessary to provide the second color filter in the slit portion. May be. At this time, the first
May be provided on the front substrate. This eliminates the need to form a color filter on the surface on which the switching element is formed. Further, the first color filter may be arranged directly above the reflection substrate.

In addition, since the electronic device according to the present invention includes the liquid crystal display device, good visibility can be ensured even in a place with little external light, while in a place with external light,
Low power consumption is achieved.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the gist of the present invention is as follows.
An active matrix method is used because the first color filter is provided near the front substrate with respect to the reflection layer formed on the rear substrate, and the second color filter for coloring transmitted light of the reflection layer is provided. Can also be applied to the passive matrix method. Among these, the active matrix method in which the pixel electrode is driven by a switching (non-linear) element has better contrast and response, and can easily achieve a high-definition display. It is advantageous. here,
The active matrix method uses a thin film transistor (TFT) as a switching element.
r) and a method using a two-terminal element such as a thin film diode (TFD), and a method using a two-terminal element such as a thin film diode (TFD).
This is advantageous in that short-circuit failure between wirings does not occur in principle because there is no intersection of wirings, and that the film forming step and the photolithography step can be shortened. Therefore, a liquid crystal display device that drives pixel electrodes by TFD is
Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment> First, a first embodiment of the present invention will be described. FIG. 1 is a block diagram showing an electrical configuration of a liquid crystal panel which is a main part of the display device. As shown in this figure, the liquid crystal panel 100 includes:
A plurality of scanning lines 212 are formed extending in the row (X) direction, while a plurality of data lines 312 are formed extending in the column (Y) direction. 3
A pixel 116 is formed at each intersection with the pixel 12. Here, each pixel 116 has a liquid crystal display element (liquid crystal layer).
118 and a TFD 220 in series. And
Each scanning line 212 is driven by the scanning line driving circuit 122, while each data line 312 is connected to the data line driving circuit 1.
24.

In this embodiment, the TFD 220
Is connected to the side of the scanning line 212 and the liquid crystal layer 118 is connected to the side of the data line 312.
The configuration may be such that the FD 220 is connected to the data line 312 side and the liquid crystal layer 118 is connected to the scanning line 212 side.

<Regarding Liquid Crystal Panel> As shown in FIG. 2, in a liquid crystal panel 100 having such an electrical configuration, a front substrate 200 having transparency and a rear substrate 300 also having transparency are fixed to each other. The liquid crystal 105 of a TN (Twist Nematic) type or the like is sealed in the gap while maintaining the gap. Among them, the front substrate 200 has, in addition to the pixel electrodes 234 shown in FIG.
In addition, a TFD 220 and the like interposed between the pixel electrode 234 and the scanning line 212 are formed, while a data line 312 and the like are formed on the rear substrate 300. Here, since the pixel electrode 234 for one column and the one data line 312 have a positional relationship facing each other, the liquid crystal layer 118 in FIG.
12 and the liquid crystal 105 sandwiched between them. Therefore, as shown in FIG. 1, the pixel 116 is electrically connected to the liquid crystal layer 118 and the TFD 220 via a series connection at each intersection between the scanning line 212 and the data line 312.

The data line 312 is connected to an ITO (Indium)
A transparent conductive film such as Tin Oxide) is formed on the overcoat layer 342 made of an acrylic resin, an epoxy resin, or the like. Here, the reason why the overcoat layer 342 is provided is that the first color filter 322,
The first color filter 32 is used for flattening a convex portion formed of the reflection layer 332 and the second color filter 324.
This is for preventing the organic substance from seeping out of the liquid crystal 2 and deteriorating the liquid crystal 105.

On the other hand, in a region on the upper surface of the rear substrate 300 facing the pixel electrode 234, undulations are formed by a process such as etching, and a second color filter 324 is formed there. On the upper surface of the second color filter 324, a reflective layer 332 having light reflectivity such as aluminum is further provided with a slit 3 serving as an opening.
35 are formed. Here, the reflected light of the reflective layer 332 is appropriately scattered by the undulation remaining on the upper surface of the second color filter 324.

The first color filter 322 and the second color filter 324 are any of the three primary colors, R (red), G (green), and B (blue), and are arranged in stripes or mosaics. They are arranged with a certain regularity such as an array or a delta array. At this time, as described later, the second color filter 324 is provided mainly to prevent a reduction in the color development of the irradiation light by the backlight unit, and thus the first color filter 324 corresponding to the same pixel electrode 234 is provided.
Color filter 322 and second color filter 3
Reference numerals 24 are the same color in the present embodiment.

In addition, in addition to the above, an alignment film (not shown) rubbed in consideration of the viewing angle characteristic is provided on the pixel electrode 23.
4 and the data lines 312. Thus, when no voltage is applied, the liquid crystal molecules are oriented along the rubbing direction. In addition, a black matrix for shielding the gap between the colored patterns is provided in a region other than the region where the first color filter 322 and the second color filter 324 are formed, but is not shown.

Next, the layout of one pixel on the front substrate 200 will be described. FIG. 3A shows TFD2
20 is a plan view showing a layout for one pixel including 20; FIG.
FIG. 2B is a cross-sectional view taken along the line AA ′. Note that, since the TFD 220 and the pixel electrode 234 are provided on the front substrate 200 in the present embodiment, FIG. 3A is a plan view seen from the back side (lower side) in FIG. Note that FIG. 3B is upside down from FIG.

As shown in FIGS. 3A and 3B, the TFD 220 is composed of a first TFD 220a and a second TFD 220b, and the insulating film 201 formed on the surface of the front substrate 200 , First metal film 2
22, an oxide film 224 serving as an insulator formed on the surface of the first metal film 222 by anodic oxidation, and second metal films 226a and 226b formed on the surface and separated from each other.
It is composed of Also, the second metal film 226a
While the scanning line 212 is used as it is, the second metal film 226 b
Are connected to a pixel electrode 234 formed of a transparent conductive film such as ITO similarly to the data line 312.

Here, the first TFD 220a becomes a second metal film 226a / oxide film 224 / first metal film 222 in order from the scanning line 212 side, and is a metal / insulator / metal sandwich. Due to the structure, the current-voltage characteristics are non-linear in both positive and negative directions. On the other hand, the second
Of the first metal film 222 / oxide film 224 / second metal film 22 in this order when viewed from the scanning line 212 side.
6b, which has current-voltage characteristics opposite to those of the first TFD 220a. Therefore, TFD2
20 has a configuration in which two elements are connected in series in opposite directions to each other.
The non-linear characteristic of the voltage is symmetrical in both the positive and negative directions.

The front substrate 200 itself is made of, for example, quartz, glass, plastic, or the like. The reason why the insulating film 201 is provided on the surface of the front substrate 200 is to prevent the first metal film 222 from peeling off from the base by heat treatment after the deposition of the second metal film, and This is to prevent impurities from diffusing into the substrate. Therefore, if these points do not matter, the insulating film 201 can be omitted.

The TFD 220 is an example of a two-terminal switching element.
-Insulator) and the like, or those in which these elements are connected in series or parallel in the reverse direction. further,
If it is not necessary to strictly make the current-voltage characteristics symmetrical in both positive and negative directions, only one element may be used.

Next, the overall configuration of the display device including the liquid crystal panel 100 will be described with reference to FIGS. Here, FIG. 4 is a perspective view illustrating a configuration of the liquid crystal panel 100, and FIG. 5 is a cross-sectional view taken along line BB ′ in FIG. In FIG. 5, the backlight unit omitted in FIG.
Are also shown.

As shown in these figures, in the liquid crystal panel 100, the front substrate 200 and the rear substrate 300 are maintained at a fixed gap by the sealing material 104 mixed with the spacer S, and the electrode forming surfaces are opposed to each other. The liquid crystal 105 is sealed in this gap. Further, polarizing plates 206 and 306 are provided on the front side of the front substrate 200 and the back side of the rear substrate 300, respectively, and the polarization axes thereof are set according to the rubbing directions of the corresponding substrates.

On the other hand, on the opposite surface of the front substrate 200,
Terminal portions protruding from the back substrate 300 are provided with IC chips 25 corresponding to the scanning signal driving circuits 122 in FIG.
0 is COG mounted from below in the figure,
An FPC (Flexible Printed CiC) for supplying a control signal to the IC chip 250 from an external control board (not shown).
rcuit) The substrate 260 is connected. Also, the back substrate 30
1, an IC chip 350 corresponding to the data line driving circuit 124 in FIG. 1 is COG-mounted from the upper side in FIG. An FPC board 360 for supplying a control signal from the control board is connected. Here, in the COG mounting on the IC chips 250 and 350, first, at a predetermined position with the substrate, a film-like anisotropic conductive film in which conductive fine particles are uniformly dispersed in an adhesive is sandwiched. Second, the IC chips 250 and 350 are pressed and heated on the substrate. The connection of the FPC boards 350 and 360 is performed in the same manner.

In place of mounting the IC chips 250 and 350 on the substrates 200 and 300 by COG, for example,
Each TCP (Tape C) on which C chips 250 and 350 are mounted
arrier package) may be electrically and mechanically connected by an anisotropic conductive film provided at a predetermined position on the substrates 200 and 300.

Further, on the back surface of the back substrate 300, a backlight unit is provided with a buffer material 106 such as silicon rubber.
Is provided via The backlight unit includes a linear fluorescent tube 601 for irradiating light and a fluorescent tube 6.
The light guide plate 603 reflects the light from the light guide 01 without fail, the diffuser plate 604 uniformly diffuses the light guided to the light guide plate 603 to the liquid crystal panel 100, and the light guide plate 60.
And a reflector 605 for reflecting light emitted from the liquid crystal panel 3 in the opposite direction to the liquid crystal panel 100 toward the liquid crystal panel 100. Here, the fluorescent tube 601 is not always turned on, but is turned on by a user's instruction or detection of a sensor when there is almost no external light.

In such a configuration, the front substrate 200
2, the light incident on the liquid crystal panel 100 is reflected by the reflective layer 332, so that the liquid crystal panel 100 functions as a reflection type while the fluorescent tube 601 of the backlight unit is turned on. Then, the irradiation light passes through the slit 335 formed in the reflection layer 332, so that the liquid crystal panel 100 functions as a transmission type.

Here, when functioning as a reflection type, incident light from the front substrate 200 side is polarized light 206 (not shown in FIG. 2) → front substrate 200 → pixel electrode 234 → liquid crystal 105 → data line 312 → When the light reaches the overcoat layer 342 → the first color filter 322 → the reflective layer 332, the light is reflected by the reflective layer, and is visually recognized by the user by following the current path in reverse. Therefore, the light that has entered the liquid crystal panel 100 passes through the first color filter 322 twice before being visually recognized by the user.

On the other hand, when functioning as a transmissive type, the light emitted by the backlight unit is applied to the polarizing plate 306 (not shown in FIG. 2) → the rear substrate 300 → the second color filter 324 → the slit 335 → the first color filter. 322
→ overcoat layer 342 → data line 312 → liquid crystal 10
5 → pixel electrode 234 → front substrate 200 → polarizer 206
(Not shown in FIG. 2) and is visually recognized by the user. Therefore, the irradiation light from the backlight unit passes through the first color filter 322 and the second color filter 324 before being visually recognized by the user.

Therefore, the irradiation light from the backlight unit is similar to the incident light from the front substrate 200 side.
Since the light passes through the color filter twice, the problem that the coloring is lightened is eliminated.

Further, when functioning as a reflection type, the reflected light passes through the first color filter 322 twice, so that the color reproducibility in the reflection type is determined only by the first color filter. On the other hand, when functioning as a transmission type,
Since the transmitted light passes through the second color filter 324 and the first color filter 322 in order, the color reproducibility in the transmission type is determined by both the first and second color filters. Therefore, by individually setting the color characteristics of both color filters, the color reproducibility of the reflection type and the transmission type can be optimized. In particular, the light that passes through the second color filter 324 and is visible to the user is only the light emitted by the backlight unit. For this reason, by setting the color characteristics of the second color filter in consideration of the spectral characteristics of the irradiation light and the like, it is possible to balance the color characteristics of the reflection type and the transmission type.

Since the liquid crystal layer 118 is composed of the pixel electrode 234, the data line 312, and the liquid crystal 105 interposed therebetween, a scanning signal is supplied to the scanning line 212, When a potential difference equal to or greater than a threshold value is applied to the TFD 220 by supplying a data signal to the TFD 312, the TFD is turned on and becomes conductive, so that predetermined charges are accumulated in the liquid crystal layer connected to the TFD. . Then, even if the TFD is turned off after the charge accumulation, if the resistance of the liquid crystal layer is sufficiently high, the charge accumulation in the liquid crystal layer is maintained. When the TFD 220 is driven in this way to control the amount of charge to be stored, the alignment state of the liquid crystal changes for each pixel, so that a predetermined display can be performed.

At this time, since it is sufficient to accumulate charges in the liquid crystal layer 118 of each pixel 116 during a part of the period, first, each scanning line 212 is sequentially applied by the scanning line driving circuit 122 (IC chip 250). Second, during the selection period of the scanning line 212, the data line driving circuit 124
A configuration in which a data signal corresponding to an image to be displayed on the data line 312 is supplied by the (IC chip 350) enables time-division multiplex driving in which the scanning line 212 and the data line 312 are shared by a plurality of pixels 116. ing.

<Second Embodiment> Next, a second embodiment of the present invention will be described. FIG. 6 is a partial cross-sectional view for explaining the structure of the liquid crystal panel according to the second embodiment. In the first embodiment described above, the first color filter 322
The second color filter 324 and the second color filter 324 are formed on the surface of the rear substrate 300 facing the front substrate 200, respectively. In the present embodiment, as shown in FIG. Are formed on the back side of the back substrate 300.

Here, the second color filter 324 is
Since it is provided to prevent the color from being lowered by coloring the irradiation light of the backlight unit, it may be formed on the back side of the back substrate 300 as in this embodiment. Note that if the second color filter 324 is provided on the back side of the back substrate 300, it will be exposed to the outside. Therefore, in practice, it is desirable to protect it with an overcoat layer or the like.

As described above, according to the second embodiment, similarly to the first embodiment, the irradiation light from the backlight unit,
That is, the transmitted light of the liquid crystal panel 100 also passes through the color filter twice, similarly to the reflected light, so that the color reproducibility of the two can be made substantially equal.

<Third Embodiment> Next, a third embodiment of the present invention will be described. FIG. 7 is a partial cross-sectional view illustrating the structure of a liquid crystal panel according to the third embodiment. In the first and second embodiments described above, the TFD 220 is formed on the front substrate 300, but in the present embodiment, the TFD 220 is formed on the rear substrate 500 side. Therefore, T
Scanning line 212 and pixel electrode 5 connected to FD 220
34 are also formed on the rear substrate 500, and data lines 312 are formed on the front substrate 400 instead.

The incident light from the front substrate side is reflected by the first color filter 3 until it is visually recognized by the user.
Since the first color filter 322 only needs to pass twice, it is not necessary to provide the first color filter 322 on the rear substrate side as in the above-described first and second embodiments. For this reason, in the third embodiment, the first color filter 324 is provided on the front substrate 400 on the surface facing the rear substrate 500. Note that the overcoat layer 342 is provided for flattening a projection formed by the first color filter 342, and the data line 312 is formed on the surface thereof.

Next, in the third embodiment, the back substrate 2
The layout of one pixel of 00 will be described. FIG.
(A) is a plan view showing a layout for one pixel including the TFD 220, and (b) is a cross-sectional view taken along the line CC '. Note that, in the third embodiment, the TFD 220 and the pixel electrode 234 are
8 (a) is a plan view when viewed from the front side (upper side) in FIG. 7, and FIG. 8 (b) is an upright It differs from FIG. 3 in certain respects.

As shown in FIGS. 8A and 8B, the TFD 220 is composed of a first TFD 220a and a second TFD 220 connected in series in opposite directions.
b is the same as in FIG. 3 except that the second TFD2
The difference from FIG. 3 is that the second metal film 226b in 20b is extended as it is to form the pixel electrode 534. That is, in the third embodiment,
By patterning the second metal film constituting the TFD 220, the second metal film 2 of the first TFD 220a is patterned.
26a and a second metal film 226a of the second TFD 220a.
At the same time, the pixel electrode 534 is simultaneously formed including the slit 535 which is an opening. As such a common metal layer, aluminum or the like having light reflectivity is suitable.

Also, undulations are selectively formed on the surface of the back substrate 500 in advance so as to impart light scattering properties to the region serving as the pixel electrode 534, but undulations are formed in the region where the TFD 220 is formed. I can't. This is because, if a TFD is formed in a region having undulations, the element size becomes non-uniform, and the nonlinear characteristics of the TFD 220 vary, resulting in display unevenness.

As described above, according to the third embodiment, similarly to the first and second embodiments, the transmitted light of the liquid crystal panel 100 passes through the color filter twice as well as the reflected light. It is possible to make the color reproducibility of both of them substantially equal. Further, in the rear substrate 500,
Since the second metal films 226a and 226b and the pixel electrode 534 are patterned with the common metal layer, it is possible to simplify the manufacturing process.

<Fourth Embodiment> Next, a fourth embodiment of the present invention will be described. FIG. 9 is a partial cross-sectional view illustrating the structure of a liquid crystal panel according to the fourth embodiment. In the third embodiment described above, the TF
Although neither the first color filter 322 nor the second color filter 324 was provided on the surface on which the DFD 220 was formed, in the present embodiment, as shown in FIG. A color filter is provided.

Here, the second surface of the rear substrate 300 is
Is formed, and the TFD element 22
It is covered with the overcoat layer 342 together with 0. In addition, the pixel electrode 534 including the slit 535 is formed on the upper surface of the overcoat layer 342 to form the second metal film 226.
b is connected via a contact hole 551. Further, a first color filter 322 is formed in the slit 535 of the pixel electrode 534, and is covered with an overcoat layer 346 in order to prevent seepage of an organic substance.

As described above, according to the fourth embodiment, the manufacturing process of the rear substrate 500 is slightly complicated. However, similarly to the other embodiments, the transmitted light to the liquid crystal panel 100 is the same as the reflected light. Since the light passes through the color filter twice, it is possible to make the color reproducibility of both the colors substantially equal.

<Applications> The present invention is not limited to the above-described first to fourth embodiments, and various applications and modifications are possible.

In each of the embodiments, the first color filter 322 and the second color filter 324 are formed separately. However, the functions of both color filters are provided by a single color filter. It is also possible. For example, in FIG. 2, the first color filter 32
2 is not only the surface of the reflection layer 332 but also the slit 332
Since the light passes through the slit 335 and penetrates into the inside, even if the second color filter 324 does not exist, the first color filter 3
Colored by 22. However, in practice, the reflection layer 335 is not sufficiently colored in general because it is very thin compared to the thickness of the color filter. For this reason, it is necessary to take measures such as intentionally increasing the thickness of the reflective layer 332 to secure an optical path length sufficient for coloring.

As described above, according to the present invention, even if a single-layer color filter is used, the same operation and effect as those of the first and second color filters can be obtained. That is, conversely, the first color filter and the second color filter in the present invention include not only a case where they are formed by separate color filters but also a case where they are formed by the same color filter. .

In each of the embodiments, the reflection layer
Although the semi-transmission / reflection function is provided by providing the slit, the invention is not limited to this. For example, when a metal having light reflectivity such as aluminum is used, the thickness of the reflection layer is made relatively thin (20 nm to 20 nm). 50 nm), it may be configured to transmit a part of the incident light from the rear substrate side.

Further, in each embodiment, the pixel 11
Although a two-terminal element such as a TFD is used as the switching element of No. 6, as described above, the present invention is not limited to this, and can be applied to a case where a three-terminal element such as a TFT is used. In addition, the present invention can be applied to a passive matrix system using no switching element.

In addition, in each embodiment, the first color filter 322 facing the same pixel electrode 234 is used.
The second color filter 324 and the second color filter 324 have substantially the same color. However, the present invention is not limited to this. Various colors may be possible by using different colors for a partial or entire region.
Further, the characteristics of the first color filter 322 and the second color filter 324 may be made different from each other to make the color reproducibility in the reflection type and the color reproducibility in the transmission type completely different.

The first color filter 322 and the second color filter 324 are arranged in a stripe arrangement, a mosaic arrangement, a delta arrangement, and the like.
A single color in a so-called solid state may be used, or a color filter may be combined.

<Electronic Apparatus> Next, the case where the transflective / semi-reflective liquid crystal panel according to the embodiment is applied to various electronic apparatuses as a display device will be described. In this case, as shown in FIG. 10, the electronic device mainly includes the display information output source 1.
000, display information processing circuit 1002, power supply circuit 100
4. Timing generator 1006, liquid crystal panel 10
0 and a drive circuit 120. The display information output source 1000 is a ROM (Read Only Me
mory), a memory such as a RAM (Random Access Memory), a storage unit such as various disks, a tuning circuit that tunes and outputs a digital image signal, and the like. Based on various clock signals generated by the timing generator 1006, a predetermined The display information such as an image signal in a format is supplied to the display information processing circuit 1002. Next, the display information processing circuit 1002 includes well-known various circuits such as an amplification / inversion circuit, a rotation circuit, a gamma correction circuit, and a clamp circuit, executes processing of input display information, and clocks the image signal. Signal CLK
Together with the drive circuit 120. Here, the driving circuit 120 is the scanning line driving circuit 1 in FIG.
22 and a data line driving circuit 124, and a test circuit and the like. Further, the power supply circuit 1004
A predetermined power is supplied to each component.

Next, some examples in which the transflective / semi-reflective liquid crystal panel according to the embodiment is used for specific electronic devices will be described.

<Part 1: Mobile Computer> First, an example in which this liquid crystal panel is applied to a mobile personal computer will be described. FIG. 11 is a perspective view showing the configuration of the personal computer. In the figure, a personal computer 1200 includes a main body 1204 having a keyboard 1202 and a liquid crystal display unit 1206. The liquid crystal display unit 1206 is configured by adding a backlight unit to the back of the liquid crystal panel 100 described above. Thus, even in a place where there is no external light, the display can be visually recognized by lighting the fluorescent tube of the backlight unit.

<Part 2: Cellular Phone> An example in which the liquid crystal panel is applied to a cellular phone will be described. FIG.
FIG. 2 is a perspective view showing the configuration of the mobile phone. In the figure, a mobile phone 1300 has a plurality of operation buttons 1302
Also, the liquid crystal panel 100 described above is provided. A backlight unit is also provided on the back of the liquid crystal panel 100.

In addition to the electronic devices described with reference to FIGS. 11 and 12, a liquid crystal television, a viewfinder type, a monitor direct-view type video tape recorder, a car navigation device, a pager, an electronic notebook, a calculator, Examples include a word processor, a workstation, a videophone, a POS terminal, and a device having a touch panel. It goes without saying that the present invention can be applied to these various electronic devices.

[0070]

As described above, according to the present invention, in both the reflective type and the transmissive type, the light visually recognized by the user passes through the color filter twice. It is possible to make the color reproducibility with the mold almost equal.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an electrical configuration of a liquid crystal panel according to a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view illustrating the structure of the liquid crystal panel.

FIG. 3A is a plan view showing a configuration of one pixel of a front substrate in the liquid crystal panel, and FIG.
It is sectional drawing of the -A 'line.

FIG. 4 is a perspective view showing a configuration of the liquid crystal panel.

FIG. 5 is a cross-sectional view taken along line BB ′ showing the configuration of the liquid crystal panel and the like.

FIG. 6 is a partial cross-sectional view illustrating a structure of a liquid crystal panel according to a second embodiment of the present invention.

FIG. 7 is a partial cross-sectional view illustrating a structure of a liquid crystal panel according to a third embodiment of the present invention.

FIG. 8A is a plan view showing a configuration of one pixel on a rear substrate of the liquid crystal panel, and FIG.
It is sectional drawing of the -C 'line.

FIG. 9 is a partial cross-sectional view illustrating a structure of a liquid crystal panel according to a fourth embodiment of the present invention.

FIG. 10 is a block diagram illustrating a schematic configuration of an electronic apparatus to which the liquid crystal panel according to each embodiment is applied.

FIG. 11 is a perspective view illustrating a configuration of a personal computer as an example of an electronic apparatus to which the liquid crystal panel is applied.

FIG. 12 is a perspective view illustrating a configuration of a mobile phone as an example of an electronic apparatus to which the liquid crystal panel is applied.

[Explanation of symbols]

 100 liquid crystal panel 105 liquid crystal 200, 400 front substrate 201 insulating film 206 polarizing plate 212 scanning line 220 TFD 222 first metal film 224 oxide film 226 Second metal film 234, 534 Pixel electrode 250 IC chip 260 FPC substrate 300, 500 Back substrate 306 Polarizing plate 312 Data line 322 First color filter 324 First 2 color filters 332 reflective layers 335, 535 slits 342 overcoat layer 350 IC chip 360 FPC board 601 fluorescent tubes 602, 605 reflective plate 603 light guide plate 604 … Diffusion plate

Continued on the front page F term (reference) 2H091 FA02Y FA14Y FA14Z FB08 FD04 FD06 GA02 GA07 GA13 HA07 LA15 LA16 2H092 JA02 JA07 JA12 JA24 JB05 JB07 JB52 JB58 KB13 KB22 NA03 PA08 PA12 QA07 5G435 AA04 BB12 BB15 BB12 BB15 BB12 BB12 BB12 CC

Claims (11)

[Claims] 1. A liquid crystal display device having a liquid crystal sandwiched between a front substrate and a rear substrate, wherein the liquid crystal display device is formed on the rear substrate, reflects incident light from the front substrate side, and reflects the rear substrate side. A reflection layer that transmits at least a part of incident light from the first substrate; a first color filter provided near the front substrate with respect to the reflection layer; A liquid crystal display device comprising: a second color filter for coloring transmitted light. 2. The liquid crystal display device according to claim 1, wherein a slit is provided in the reflection layer. 3. The liquid crystal display device according to claim 1, wherein the reflection layer is formed of a light-reflective metal film having a thickness of 20 nm to 50 nm. 4. The liquid crystal display device according to claim 1, wherein the coloring by the second color filter and the coloring by the first color filter are substantially the same color. 5. The liquid crystal display device according to claim 1, further comprising a light source for irradiating light incident on the rear substrate side and emitted from the front substrate side. 6. The liquid crystal display device according to claim 1, further comprising a pixel electrode and a switching element arranged corresponding to intersections of a plurality of scanning lines and a plurality of data lines. 7. The pixel electrode and the switching element are provided on the front substrate, respectively, while the first color filter is provided on the rear substrate together with the second color filter. The liquid crystal display device according to claim 6. 8. The liquid crystal display device according to claim 6, wherein the pixel electrode and the switching element are provided on the back substrate, respectively. 9. The liquid crystal display device according to claim 8, wherein the reflection layer and the pixel electrode are formed by patterning the same conductive layer having light reflectivity. 10. The liquid crystal display device according to claim 8, wherein the second color filter is located on a side of the back substrate opposite to a side facing the reflection substrate. 11. An electronic apparatus comprising the liquid crystal display device according to claim 1. Description: