JP4804547B2 - Liquid crystal display - Google Patents

Description

  The present invention relates to a liquid crystal display device, and more particularly to a so-called partial transmission type active matrix liquid crystal display device.

  An active matrix type liquid crystal display device includes a gate signal line extending in the x direction and arranged in parallel in the y direction on the liquid crystal side surface of one of the transparent substrates opposed to each other through the liquid crystal. And a drain signal line extending in the y direction and juxtaposed in the x direction, and a region surrounded by these signal lines is defined as a pixel region.

  In each pixel region, a thin film transistor operated by a scanning signal from a gate signal line on one side and a pixel electrode to which a video signal from a drain signal line is supplied via the thin film transistor are formed.

  Further, in such a liquid crystal display device, what is called a partially transmissive type is that each pixel region has a light transmissive portion that is a region through which light from a backlight disposed on the back side can be transmitted, the sun, etc. And a light reflecting portion which is a region where extraneous light is reflected.

  The light transmissive portion is formed as a region constituting the pixel electrode by a light transmissive conductive layer, and the light reflecting portion is formed as a region constituting the pixel electrode by a non-light transmissive conductive layer having a light reflecting function. It has become.

  The liquid crystal display device thus configured can be used as a light transmission mode by turning on a backlight, and can also be used as a light reflection mode using external light such as sunlight.

  However, the liquid crystal display device configured as described above must pass through the color filter twice in the light path passing through the light transmission part and the light path passing through the light reflection part, for example, in the latter case. However, in the former case, it is not configured under the same condition because it only needs to pass once.

  For this reason, it is pointed out that the color balance is not uniform between when used in the light transmission mode and when used in the light reflection mode, and it is difficult to set the color balance adjustment accordingly. It was.

  The present invention has been made based on such circumstances, and an object of the present invention is to provide a liquid crystal display device capable of suitably setting the color balance.

  Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.

Means 1.
The liquid crystal display device according to the present invention includes, for example, a pixel region having a light reflection part and a light transmission part on the liquid crystal side surface of one of the substrates arranged to face each other through the liquid crystal,
A color filter is formed in a pixel region on the liquid crystal side surface of the other substrate among the substrates, and the color filter has an opening or a notch formed in a part of a portion facing the light reflecting portion,
A material layer having a thickness substantially equal to a step generated by the color filter is formed in a region facing the opening or notch of the color filter on the liquid crystal side surface of the one substrate. .

Mean 2.
The liquid crystal display device according to the present invention includes, for example, a pixel region having a light reflection part and a light transmission part on the liquid crystal side surface of one of the substrates arranged to face each other through the liquid crystal,
A color filter is formed in a pixel region on the liquid crystal side surface of the other substrate among the substrates, and the color filter has a plurality of openings scattered in a portion facing the light reflecting portion. It is a feature.

Means 3.
The liquid crystal display device according to the present invention is characterized in that, for example, the diameter of the opening is set to 20 μm or less on the premise of the configuration of the means 2.

Means 4.
The liquid crystal display device according to the present invention includes, for example, a pixel region having a light reflection part and a light transmission part on the liquid crystal side surface of one of the substrates arranged to face each other through the liquid crystal,
Among the substrates, color filters of different colors are formed in pixel regions adjacent to each other in the pixel region on the liquid crystal side of the other substrate, and at least one color filter is a part of a portion facing the light reflecting portion. An opening or notch is formed in the
At least one of the light transmitting portions in each pixel region of the color filters of different colors is different in size from other light transmitting portions.

Means 5.
The liquid crystal display device according to the present invention includes, for example, a pixel region having a light reflection part and a light transmission part on the liquid crystal side surface of one of the substrates arranged to face each other through the liquid crystal,
A black matrix in which an opening is provided in a portion of each substrate excluding the periphery of each pixel region on the liquid crystal side surface of the other substrate, and color filters of different colors in pixel regions adjacent to each other among the pixel regions. Formed,
In addition, at least one color filter has an opening or a notch in a part of the portion facing the light reflecting portion, and the opening of the black matrix has a color filter of a color different from the color filter color in the pixel region. It is characterized in that the size of the black matrix is different from that of other pixel regions.

Means 6.
The liquid crystal display device according to the present invention includes, for example, a pixel region having a light reflection part and a light transmission part on the liquid crystal side surface of one of the substrates arranged to face each other through the liquid crystal,
When the intensity of the electric field generated in the pixel region is small, black display is performed,
A color filter of a different color is formed in a pixel region adjacent to each other among the pixel regions on the liquid crystal side surface of the other substrate among the substrates,
At least one of the light transmission portions in each pixel region of the different color filter is different in size from the other light transmission portions.

Mean 7
The liquid crystal display device according to the present invention is premised on, for example, any one of means 1 to 6, and each pixel region is formed as a region surrounded by a pair of gate signal lines and a pair of drain signal lines. And a video signal from the drain signal line is supplied to the pixel electrode of the light transmission portion and the pixel electrode of the light reflection portion via the thin film transistor.

Means 8.
The liquid crystal display device according to the present invention is characterized in that, for example, any one of the means 4, 5 and 6 is premised, and each color filter having a different color is made of cyan, magenta and yellow, respectively.

Means 9.
The liquid crystal display device according to the present invention is premised on, for example, any one of the means 4, 5, and 6, and the area of the light reflecting portion of the pixel region where the blue color filter is formed is formed by the color filter of another color. It is characterized by being formed larger than the area of the light reflecting portion of the pixel region.

Means 10.
The liquid crystal display device according to the present invention is premised on, for example, any one of the means 4, 5, and 6, and the area of the light reflecting portion of the pixel region where the yellow color filter is formed is formed by the color filter of another color. It is characterized in that it is formed smaller than the area of the light reflecting portion of the pixel region.

Means 11.
The liquid crystal display device according to the present invention is characterized in that, for example, on the premise of the means 4, the total area in one pixel of the opening or notch of the color filter differs depending on the color.

  As is apparent from the above description, according to the liquid crystal display device of the present invention, the color balance can be adjusted appropriately.

It is a top view which shows one Example of the pixel of the liquid crystal display device by this invention. 1 is an overall equivalent circuit diagram showing an embodiment of a liquid crystal display device according to the present invention. It is sectional drawing in the III-III line of FIG. It is a top view which shows each Example of a structure of the color filter in each pixel of the liquid crystal display device by this invention. It is process drawing which shows one Example of the manufacturing method of the liquid crystal display device by this invention. It is a top view which shows the other Example of the pixel of the liquid crystal display device by this invention. It is a top view which shows the other Example of the pixel of the liquid crystal display device by this invention. It is a top view which shows one Example of a structure of the black matrix in each pixel of the liquid crystal display device by this invention. It is sectional drawing which shows the other Example of the liquid crystal display device by this invention. It is sectional drawing which shows the other Example of the liquid crystal display device by this invention.

Hereinafter, embodiments of a liquid crystal display device according to the present invention will be described with reference to the drawings.
Example 1.
<Overall equivalent circuit>
FIG. 2 is a plan view showing one embodiment of the entire equivalent circuit of the liquid crystal display device according to the present invention.
In the figure, there is a pair of transparent substrates SUB1 and SUB2 arranged to face each other via a liquid crystal, and the liquid crystal is sealed by a sealing material SL that also serves to fix the other transparent substrate SUB2 to one transparent substrate SUB1.

  On the liquid crystal side surface of the one transparent substrate SUB1 surrounded by the sealing material SL, the gate signal lines GL extending in the x direction and arranged in parallel in the y direction, and extending in the y direction and aligned in the x direction. A drain signal line DL is provided.

  A region surrounded by each gate signal line GL and each drain signal line DL constitutes a pixel region, and a matrix aggregate of these pixel regions constitutes a liquid crystal display unit AR.

  In each pixel region, a thin film transistor TFT operated by a scanning signal from one side gate signal line GL and a pixel electrode PX to which a video signal from one side drain signal line DL is supplied via the thin film transistor TFT are formed. Has been.

  The pixel electrode PX forms a capacitive element Cadd between another gate signal line GL different from the gate signal line GL for driving the thin film transistor TFT, and the capacitive element Cadd causes the pixel The video signal supplied to the electrode PX is stored for a relatively long time.

  The pixel electrode PX generates an electric field between the pixel electrode PX and the counter electrode CT formed in common in each pixel region on the other transparent substrate SUB2 side, and controls the light transmittance of the liquid crystal by this electric field. .

  One end of each of the gate signal lines GL extends beyond the sealing material SL, and the extending end constitutes a terminal to which the output terminal of the vertical scanning drive circuit V is connected. The input terminal of the vertical scanning drive circuit V receives a signal from a printed circuit board disposed outside the liquid crystal display device.

  The vertical scanning drive circuit V is composed of a plurality of semiconductor devices, and a plurality of gate signal lines GL adjacent to each other are grouped, and one semiconductor device is assigned to each group.

  Similarly, one end of each of the drain signal lines DL extends beyond the seal material SL, and the extending end constitutes a terminal to which the output terminal of the video signal driving circuit He is connected. . The input terminal of the video signal driving circuit He receives a signal from a printed circuit board arranged outside the liquid crystal display device.

  This video signal drive circuit He is also composed of a plurality of semiconductor devices, and a plurality of adjacent drain signal lines DL are grouped, and one semiconductor device is assigned to each group.

  One of the gate signal lines GL is sequentially selected by a scanning signal from the vertical scanning driving circuit V.

  Each drain signal line DL is supplied with a video signal by the video signal driving circuit He in accordance with the selection timing of the gate signal line GL.

  A backlight BL is disposed on the back surface of the liquid crystal display device configured as described above, and when the liquid crystal display device is used in a transmissive mode, the light source is turned on.

The vertical scanning circuit V and the video signal driving circuit He are configured to be mounted on the transparent substrate SUB1, respectively. However, the present invention is not limited to this and may be externally attached to the transparent substrate SUB1. Of course it is good.
<Pixel configuration>
FIG. 1 is a plan view showing an embodiment of the pixel region. The figure shows R, G, and B pixels as color pixels, but they differ only in the color of the color filter and the proportion of the light reflecting portion and the light transmitting portion is different. The configuration is almost the same.

  In the following description, description will be given focusing on one of the three pixels. In addition, the cross section in the III-III line in the same figure is shown in FIG.

  In the figure, first, a pair of gate signal lines GL extending in the x direction and arranged in parallel in the y direction are formed on the liquid crystal side surface of the transparent substrate SUB1. The gate signal line GL is made of, for example, Al (aluminum), and an anodic oxide film AOF is formed on the surface thereof.

  These gate signal lines GL surround a rectangular region together with a pair of drain signal lines DL described later, and this region is configured as a pixel region.

  A light-transmitting pixel electrode (first pixel electrode) PX1 such as an ITO (Indium-Tin-Oxide) film is formed in the central portion excluding the slight periphery of the pixel region.

  This pixel electrode PX1 functions as a pixel electrode in a region where light from the backlight BL can transmit in the pixel region, and is distinguished from a pixel electrode (second pixel electrode) PX2 that also serves as a reflective electrode, which will be described later. is there.

  An insulating film GI made of, for example, SiN (silicon nitride) is formed on the surface of the transparent substrate SUB1 on which the gate signal line GL and the pixel electrode PX1 are thus formed. This insulating film GI is formed so as to extend over the region where the thin film transistor TFT is formed (part of the gate signal line GL) and the intersection between the gate signal line GL and the drain signal line DL in the vicinity thereof.

  The insulating film GI formed in the formation region of the thin film transistor TFT functions as a gate insulating film of the thin film transistor TFT, and the insulating film GI formed at the intersection of the gate signal line GL and the drain signal line DL serves as an interlayer insulating film. It comes to have the function of.

  A semiconductor layer AS made of amorphous Si (silicon) is formed on the surface of the insulating film.

  This semiconductor layer AS is that of the thin film transistor TFT, and by forming a drain electrode SD1 and a source electrode SD2 on the upper surface thereof, an MIS type transistor having an inverted stagger structure having a part of the gate signal line GL as a gate electrode is formed. can do.

  The semiconductor layer AS is also formed to extend at the intersection of the gate signal line GL with the drain signal line DL, thereby strengthening the function of the signal lines as an interlayer insulating film together with the insulating film GI. ing.

  Although not clarified in FIG. 3, a semiconductor layer doped with a high concentration impurity (for example, phosphorus) is formed on the surface of the semiconductor layer AS and at the interface between the drain electrode SD1 and the source electrode SD2. The contact layer d0 is constituted by this semiconductor layer.

  The drain electrode SD1 and the source electrode SD2 are formed at the same time when the drain signal line DL is formed, for example.

  That is, a drain signal line DL extending in the y direction and juxtaposed in the x direction is formed, and a part of the drain signal line DL is extended to the upper surface of the semiconductor layer AS to form the drain electrode SD1. A source electrode SD2 is formed by being separated from the electrode SD1 by the channel length of the thin film transistor TFT.

  The drain signal line DL is composed of, for example, a sequential laminate of Cr and Al.

  The source electrode SD2 extends slightly from the surface of the semiconductor layer AS to the pixel region side so as to be electrically connected to the pixel electrode PX1 and to be connected to the pixel electrode PX2 that also serves as a reflective electrode described later. The contact portion is formed.

  Here, the extending portion of the source electrode SD2 has a function of not only connecting the pixel electrodes PX1 and PX2 as described above, but also a light reflecting portion (a region where a pixel electrode PX2 described later is formed). ), The pixel electrode PX2 is formed so as to extend over most of the region of the light reflecting portion so that the height difference due to the step is not significantly increased.

  That is, when the extension part of the source electrode SD2 is only provided with a function of connecting the pixel electrodes PX1 and PX2, the extension part may be formed as a contact part, and the extension part is relatively It will be short. As a result, a step around the extending portion becomes apparent on a surface (an upper surface of a protective film PSV described later) on which a pixel electrode PX2 also serving as a reflective electrode described later is formed, and a step is also formed on the surface of the pixel electrode PX2. Will be.

  Further, by adopting the configuration as in this embodiment, the extended portion of the source electrode SD2 occupies a relatively large area, which means that the side becomes relatively long.

  For this reason, in the manufacture of the liquid crystal display device, impurities such as dust are less likely to remain in the vicinity of the pixel electrode PX2, and harmful effects due to the impurities can be removed.

  Incidentally, in the case of a source electrode of a thin film transistor TFT having a function as a contact portion, the area of the contact portion is small, and its side is also slightly complicated by selective etching by photolithography technology, and impurities such as dust remain there. In many cases, the function as the contact portion is impaired.

  A protective film PSV made of, for example, SiN is formed on the surface of the transparent substrate SUB1 on which the drain signal line DL, the drain electrode SD1 and the source electrode SD2 of the thin film transistor TFT are thus formed. This protective film PSV is a layer that avoids direct contact with the liquid crystal of the thin film transistor TFT, and is intended to prevent deterioration of characteristics of the thin film transistor TFT.

  Further, a contact hole CH is formed in the protective film PSV, and a part of the source electrode SD2 of the thin film transistor TFT is exposed in the contact hole CH.

  A pixel electrode PX2 that also serves as a reflective electrode is formed on the upper surface of the protective film. This pixel electrode is composed of a non-translucent conductive film made of a sequential laminate of, for example, Cr and Al.

  The pixel electrode PX2 is formed so as to occupy most of the pixel region while avoiding the region serving as the light transmission part.

  Thereby, the region where the pixel electrode PX2 is formed functions as a light reflecting portion in the pixel region, and the formation region of the pixel electrode PX1 exposed (viewed in a plan view) from the pixel electrode PX2 functions as a light transmitting portion. It is supposed to be.

  In this embodiment, the area occupied by the light transmitting portion of the pixel region in charge of blue (B) is formed smaller than the area occupied by the light transmitting portion of the pixel region in charge of other colors (R, G). Yes. In other words, the area of the second pixel electrode PX2 in the pixel area responsible for blue is formed larger than the area of the first pixel electrode PX2 in the pixel area responsible for other colors.

  The reason for this is that the amount of light from the backlight irradiated through the light transmission part is suitable for mixing the three primary colors when it is blue, and the ratio of the light transmission part to the light reflection part of this light quantity is It is because it becomes more suitable by setting appropriately.

  A part of the pixel electrode PX2 is electrically connected to the source electrode SD2 of the thin film transistor TFT through a contact hole CH formed in a part of the protective film PSV.

  Further, the pixel electrode PX2 is formed to extend until it overlaps with another adjacent gate signal line GL different from the gate signal line GL for driving the thin film transistor TFT, and the protective film PSV is formed as a dielectric in this portion. A capacitor element Cadd serving as a body film is formed.

  Thus, an alignment film (not shown) is formed on the upper surface of the transparent substrate SUB1 on which the pixel electrode PX2 is formed so as to cover the pixel electrode PX2 and the like. This alignment film is in direct contact with the liquid crystal LC, and the initial alignment direction of the molecules of the liquid crystal is determined by rubbing formed on the surface thereof.

  The transparent substrate SUB2 is arranged so as to face the transparent substrate SUB1 thus configured via the liquid crystal LC, and the black matrix BM is formed on the surface of the transparent substrate SUB2 on the liquid crystal side so as to define each pixel region. Is formed. That is, at least the black matrix BM formed in the liquid crystal display portion AR has a pattern in which openings are formed in the regions that leave the periphery of each pixel region, thereby improving the display contrast.

  Further, the black matrix BM is formed so as to sufficiently cover the thin film transistor TFT on the transparent substrate SUB1 side, and prevents deterioration of the characteristics of the thin film transistor TFT by preventing the irradiation of the external light to the thin film transistor TFT. Yes. The black matrix BM is composed of a resin film containing a black pigment, for example.

  A color filter FIL is formed on the surface of the transparent substrate SUB2 on which the black matrix BM is formed, covering the opening of the black matrix BM. This color filter is made up of, for example, red (R), green (G), and blue (B) color filters. For example, a red filter is commonly formed in each pixel region group arranged in the y direction. It is formed in an array such as a red (R) color, a green (G) color, a blue (B) color, a red (R) color,. Yes. Each of these filters is composed of a resin film containing a pigment corresponding to the color. Needless to say, the color of each filter may be cyan, magenta, or yellow.

  Here, in this embodiment, the color filter FIL is formed in a part of the pixel region, and for example, as shown in FIG. 4A, it is formed in the central portion excluding the left and right of the pixel region. ing. In other words, an opening (or notch) HL is formed at a portion facing a part of the second pixel electrode PX2 (left and right of the pixel region).

  The reason why the color filter FIL is configured as described above is that the brightness of each pixel at the time of reflection can be adjusted from the viewpoint of mixing the three primary colors. Thereby, even if it is a case where it cannot adjust only by changing the area ratio of a light transmission part and a light reflection part with a color, a color balance and brightness can be adjusted, and a freedom degree increases. Furthermore, the area of the opening HL may be different from the area of the opening HL of the color filter FIL of the pixel region in charge of another adjacent color.

  In this case, it has been confirmed that the color adjustment can be easily performed by setting the opening HL of the blue color filter FIL to be smaller than the openings HL of the color filters FIL of other colors. Therefore, as another embodiment, the openings HL may be provided in the color filters FIL of other colors without providing the openings HL of the blue color filter FIL.

  When the color filter FIL is configured in this way, it is possible to adjust the color balance, and as described above, the area of the light transmitting portion of the pixel region in charge of blue is the same as that of the pixel region in charge of other colors. For example, the area of the light transmission part of the pixel region in charge of other colors can be made the same without making it smaller than the area of the light transmission part.

  Although the provision of the opening HL in the color filter FIL in this way prevents the uniform thickness of the liquid crystal LC, the step is sufficiently eliminated on the transparent substrate SUB1 side as described above. Therefore, it can be suppressed to a range where there is virtually no harmful effect.

  A flattening film OC is formed on the surface of the transparent substrate SUB2 on which the black matrix BM and the color filter FIL are formed so as to cover the black matrix BM and the color filter FIL. The planarization film OC is made of a resin film that can be formed by coating, and is provided to reduce the level difference that becomes apparent due to the formation of the black matrix BM and the color filter FIL.

  A translucent conductive film made of, for example, an ITO film is formed on the upper surface of the planarizing film OC, and a common counter electrode CT is formed in each pixel region by this conductive film.

  An alignment film (not shown) is formed on the surface of the planarizing film OC, and this alignment film is in direct contact with the liquid crystal LC, and the initial alignment direction of the molecules of the liquid crystal by rubbing formed on the surface. Is supposed to determine.

  The liquid crystal display device thus formed is formed by extending the source electrode SD2 of the thin film transistor TFT over a region corresponding to the light reflecting portion of the pixel region.

  For this reason, the pixel electrode PX2 formed on the light reflecting portion via the protective film PSV is formed in a flat shape having no height difference due to a step.

  This means that the layer thickness of the liquid crystal becomes uniform in the light reflecting portion, and the reduction in contrast caused by this variation can be greatly suppressed.

  Although not a light reflecting portion, the height of the pixel electrode PX2 with respect to the transparent substrate SUB1 in the portion where the capacitive element Cadd is formed should be substantially equal to the height of the pixel electrode PX2 with respect to the transparent substrate SUB1 in the light reflecting portion. Can do.

  The portion where the capacitive element Cadd is formed is a portion covered with the black matrix BM, but in the portion close to the capacitive element Cadd in the opening of the black matrix BM, the transparent substrate SUB1 of the pixel electrode PX2 is formed. It is possible to prevent the influence due to the difference in height with respect to.

  Therefore, the difference between the layer thickness of the gate signal line GL, which is the portion of the capacitive element Cadd, and the total layer thickness of the pixel electrode PX1 and the source electrode SD2 of the thin film transistor TFT under the reflecting portion is set to 0.1 μm or less. As a result, the height variation of the pixel electrode PX2 with respect to the transparent substrate SUB1 can be set to 0.1 μm or less.

  As a result, the layer thickness of the liquid crystal LC can be made substantially uniform in the light reflecting portion of the pixel region, and thus the reduction in contrast can be suppressed.

  In the above-described embodiment, the source electrode SD2 of the thin film transistor TFT is sufficiently extended to the region of the light reflecting portion, thereby avoiding the generation of a step in the pixel electrode PX2 formed thereabove.

  However, it goes without saying that the same effect as described above may be brought about by using another material layer electrically (or physically) separated from the source electrode SD2.

  In this case, since the film thickness of the material layer can be set regardless of the source electrode SD2 of the thin film transistor TFT, there is an effect that the pixel electrode PX2 can be easily flattened.

  In the above-described embodiment, the color filter FIL is provided with the opening (notch) HL in the left and right portions of the pixel region and facing the second pixel electrode PX2. As shown in FIG. 4B, it goes without saying that openings may be formed in the upper and lower portions of the pixel region and in the portion facing the second pixel electrode PX2. Further, as shown in FIG. 4C, it is a matter of course that an opening having a relatively large area may be provided in a substantially central portion of the pixel region. Furthermore, as shown in FIG. 4D, it is needless to say that a plurality of small openings having a diameter of 20 μm or less, for example, scattered in the substantially central portion of the pixel region may be formed.

  With the configuration shown in FIG. 4D, the influence of the step due to the opening of the color filter FIL can be reduced, and thereby the liquid crystal layer thickness can be made uniform.

In this case, as described above, in each color filter FIL, for example, the area of the opening of the blue color filter FIL may be reduced and the opening may not be formed.
"Production method"
Hereinafter, an example of a manufacturing method of the configuration on the transparent substrate SUB1 side in the above-described liquid crystal display device will be described with reference to FIG.

Step 1. (Fig. 5 (a))
A transparent substrate SUB1 is prepared, and Al is formed with a film thickness of about 300 nm on the main surface (surface on the liquid crystal side) by sputtering, for example, and this is selectively etched by photolithography to form gate signal lines GL. As the etchant, for example, a mixed solution of phosphoric acid, hydrochloric acid, and nitric acid is used.

  Then, the gate signal line GL is anodized in a tartaric acid solution to form an anodized film AOF on the surface thereof. An appropriate film thickness of the anodic oxide film AOF is about 180 nm.

Step 2. (Fig. 5 (b))
A transparent conductive film made of, for example, an ITO (Indium-Tin-Oxide) film is formed on the main surface of the transparent substrate SUB1 on which the gate signal line GL is formed with a film thickness of about 100 nm, and this is selected by photolithography technology. Etching is performed to form the pixel electrode PX1. For example, an aqua regia solution is used as the etching solution.

Step 3. (Fig. 5 (c))
An insulating film made of SiN is formed with a film thickness of about 240 nm on the main surface of the transparent substrate SUB1 on which the pixel electrode PX1 is formed, for example, by a CVD method. Then, after forming an amorphous silicon layer with a thickness of about 200 nm by the same method, an n ⁺ type amorphous silicon layer doped with phosphorus (P) is further formed with a thickness of about 35 nm.

  Then, selective etching by a photolithography technique is performed, and the semiconductor layer and the insulating film are collectively etched to form the insulating film GI and the semiconductor layer AS. As the etching in this case, dry etching using sulfur hexafluoride gas is appropriate.

  In this case, since the etching rate of amorphous silicon is higher than that of the insulating film, a forward taper of about 4 ° is formed on the side forming the outline of the semiconductor layer AS. Thus, a forward taper of about 70 ° is formed.

Step 4. (Fig. 5 (d))
A Cr layer and an Al layer are sequentially formed on the main surface of the transparent substrate SUB1 on which the insulating film GI and the semiconductor layer AS are formed, for example, by sputtering. In this case, it is appropriate that the Cr layer has a thickness of 30 nm and the Al layer has a thickness of 200 nm.

  Thereafter, selective etching by photolithography is performed to form a drain signal line DL having a two-layer structure, a drain electrode SD1 and a source electrode SD2 of the thin film transistor TFT.

  In this case, a mixed solution of phosphoric acid, hydrochloric acid and nitric acid is suitable as the Al etching solution, and a ceric ammonium nitrate solution is suitable as the Cr etching solution.

Then, using the drain electrode SD1 and the source electrode SD2 of the patterned thin film transistor TFT as a mask, the n ⁺ type amorphous silicon layer on the surface of the semiconductor layer AS exposed therefrom is etched. As an etchant in this case, dry etching using sulfur hexafluoride gas is appropriate.

Step 5. (Fig. 5 (e))
On the main surface of the transparent substrate SUB1 on which the drain signal line DL, the drain electrode SD1 and the source electrode SD2 of the thin film transistor TFT are formed, SiN is formed with a film thickness of about 600 nm using, for example, the CVD method, and this is selected by photolithography technology Etching is performed to form the protective film PSV.

  In this etching, a contact hole CH for exposing a part of the extending portion of the source electrode SD2 of the thin film transistor TFT is formed at the same time.

Step 6. (Fig. 5 (f))
On the main surface of the transparent substrate SUB1 on which the protective film PSV is formed, a Cr layer with a layer thickness of about 30 nm and an Al layer with a layer thickness of about 200 nm are sequentially formed by sputtering, for example, and this is selected by photolithography technology. Etching is performed to form a pixel electrode PX2 that also serves as a reflective electrode.

  In this case, a mixed solution of phosphoric acid, hydrochloric acid and nitric acid is suitable as the Al etching solution, and a ceric ammonium nitrate solution is suitable as the Cr etching solution.

  In this case, the pixel electrode PX2 has an opening so as to occupy about half of the pixel area.

  Note that, instead of sequentially forming the Cr layer and the Al layer as the pixel electrode PX2, a Mo alloy and Al may be sequentially formed, or a Mo alloy and an Al alloy may be sequentially formed. As the Mo alloy, MoCr is preferable. In this case, it has the effect that it can etch at once.

Example 2
6 (a) to 6 (e), 7 (a) and 7 (b) are configuration diagrams showing other embodiments of the liquid crystal display device according to the present invention, and correspond to FIG.

  FIG. 6A shows a configuration in which the second protective film PSV2 is formed on the upper surface of the pixel electrode PX2 so as to cover the pixel electrode PX2. FIG. 6B shows a configuration in which an opening is formed in the protective film PSV in a region corresponding to the light transmission portion. FIG. 6C shows a configuration in which the second protective film PSV2 is formed on the upper surface of the pixel electrode PX2 so as to cover the pixel electrode PX2, and both the protective film PSV and the second protective film PSV2 transmit light. The opening is formed in the region corresponding to the part. FIG. 6D shows a configuration in which the second protective film PSV2 is formed on the upper surface of the pixel electrode PX2 so as to cover the pixel electrode PX2, and an opening is formed only in the protective film PSV in a region corresponding to the light transmission portion. It is set as the formed structure. FIG. 6E shows a configuration in which the second protective film PSV2 is formed on the upper surface of the pixel electrode PX2 so as to cover the pixel electrode PX2, and both the protective film PSV and the second protective film PSV2 transmit light. In the region corresponding to the portion, openings are collectively formed.

  FIG. 7A shows the gate electrode GL formed of a metal other than the Al layer whose surface is anodized, for example, composed of an alloy layer of Mo and Cr.

  Further, in FIG. 7B, the part different from the case of FIG. 3 is that a material layer DML for height adjustment is formed in the part where the light reflecting part and the capacitive element Cadd are formed.

  Thereby, the height difference of each pixel electrode PX2 with respect to the transparent substrate SUB1 can be set to 0.1 μm or less in each of those portions.

  Therefore, the material layer DML for height adjustment need not be formed in each of the portions where the light reflecting portion and the capacitive element Cadd are formed, as shown in FIG. Of course, it may be formed.

Example 3
FIG. 8 is a block diagram showing another embodiment of the liquid crystal display device according to the present invention, and is a plan view showing a pattern of a black matrix BM formed in each pixel for color display.

  In the figure, the openings in the respective pixels (R display pixels, G display pixels, and B display pixels) of the black matrix BM have different areas.

  By forming an opening (notch) in the color filter FIL, the color balance is adjusted, and further, the opening is made in each pixel of the black matrix BM. Thereby, there is an effect that the degree of freedom in adjusting the color balance is increased.

  The present embodiment may be configured based on the configuration of each of the above-described embodiments, or may be configured by combining some configurations.

Example 4
Further, on the premise of the configuration of each embodiment described above, a so-called normally black mode in which black display is possible when there is no voltage difference between the pixel electrode PX and the counter electrode CT may be employed.

  It has been confirmed that the normally black mode is more likely to be colored due to the non-uniformity of the liquid crystal layer thickness compared to the normally white mode.

  In the embodiment described above, flattening can be achieved on the surface of the transparent substrate SUB1 on the liquid crystal side, and from this, even in the normally black mode, it is possible to obtain one that hardly causes coloring. .

  In this case, needless to say, it is not always necessary to provide a color balance adjustment opening in the color filter FIL or the black matrix BM.

Example 5 FIG.
FIG. 9 is a sectional view showing another embodiment of the pixel of the liquid crystal display device according to the present invention and corresponds to FIG.

  An opening (or notch) is formed in the color filter FIL formed on the transparent substrate SUB2 side, and the color filter is provided in a region facing the opening (or notch) on the liquid crystal side surface on the transparent substrate SUB1 side. That is, a material layer having a layer thickness substantially equal to a step generated by the opening (notch) of the FIL is formed.

  In this embodiment, the material layer is constituted by a stacked body of an insulating film GI and a semiconductor layer AS formed by patterning between the first pixel electrode PX1 and the source electrode SD2.

  In this case, the formation of the material layer can prevent the thickness of the liquid crystal layer from changing due to the opening of the color filter FIL.

  That is, as described above, the liquid crystal side surface of the transparent substrate SUB1 is sufficiently flat. For example, when the gap with the transparent substrate SUB2 is not secured through the spacer SP made of beads, the color filter FIL In the opening, the liquid crystal layer thickness is prevented from being increased by providing a convex portion made of the material layer on the transparent substrate SUB1 side.

  In this embodiment, the planarizing film OC is formed on the surface of the transparent substrate SUB2 on which the color filter FIL is formed so as to cover the color filter FIL.

  For this reason, the level difference caused by the opening or notch of the color filter FIL that appears on the surface of the planarizing film OC is formed smaller than the layer thickness of the color filter FIL. For this reason, the layer thickness of the material layer can be made smaller than the layer thickness of the color filter FIL.

  In this embodiment, it goes without saying that the configurations shown in the other embodiments described above can be applied together.

Example 6
FIG. 10 is a sectional view showing another embodiment of the pixel of the liquid crystal display device according to the present invention and corresponds to FIG.

  The difference from FIG. 9 is that the planarizing film OC is not formed on the transparent substrate SUB2 side.

  For this reason, the level | step difference of the opening (notch) formed in the color filter FIL will become larger than the case where it shows in Example 5. FIG.

  Therefore, on the transparent substrate SUB1 side, a material for forming the gate signal line GL is stacked in addition to the above-described material layer, and the total height of the stacked body is adjusted to the step of the opening (notch). I have to.

  SUB1, SUB2 ... transparent substrate, GL ... gate signal line, DL ... drain signal line, PX1 ... pixel electrode (translucent), PX2 ... pixel electrode (reflection electrode), TFT ... thin film transistor, Cadd ... capacitor element, CT ... opposite electrode.

Claims (4)

A first substrate and a second substrate disposed opposite to each other via a liquid crystal layer;
A plurality of pixels having a light reflecting portion and a light transmitting portion;
A liquid crystal display device comprising a black matrix provided with openings,
The liquid crystal layer is formed thicker in the light transmission part than the light reflection part,
The plurality of pixels include a first pixel in which a color filter of a first color is formed in the opening of the black matrix, and a color filter of a second color different from the first color in the opening of the black matrix. And a second pixel formed with
In the color filter of at least one color, an opening or a notch is formed in a part of the portion of the liquid crystal layer facing the thin light reflecting portion,
Area of the opening of the black matrix of the first pixel, unlike the area of the second of said black matrix of the opening of the pixel,
The color filter is selected from red, green, and blue,
A liquid crystal display device , wherein an area of a light reflecting portion of a pixel in which a blue color filter is formed is larger than an area of a light reflecting portion of a pixel in which a color filter of another color is formed . A first substrate and a second substrate disposed opposite to each other via a liquid crystal layer;
A liquid crystal display device comprising a plurality of pixels having a light reflecting portion and a light transmitting portion,
The liquid crystal layer is formed thicker in the light transmission part than the light reflection part,
A color filter is formed on the second substrate, and the color filter of at least one color has an opening or a notch formed in a part of the liquid crystal layer facing the thin light reflecting portion, and
The first substrate is provided with a convex portion having a layer thickness substantially equal to a step formed by the opening or notch of the color filter in a region facing the opening or notch of the color filter. Liquid crystal display device. The pixel is formed as a region surrounded by a pair of gate signal lines and a pair of drain signal lines, and is operated by a scanning signal from the gate signal line, and a video signal from the drain signal line through the thin film transistor. 3. The liquid crystal display device according to claim 1, further comprising: a pixel electrode of a light transmitting portion and a pixel electrode of a light reflecting portion to which light is supplied. The liquid crystal display device according to claim 1 or 2, characterized in that it has a backlight.

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