JP2005117055A - Display device and rear projection type liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a configuration in which the luminance and contrast of each color are made substantially the same in a liquid crystal display device of RGB composition type. <P>SOLUTION: A pixel region and a peripheral drive circuit region are formed on the same substrate, a thin film transistor formed in the pixel region has a crystalline silicon film having a source region, a drain region, a lightly doped region, and a channel formation region formed on an underlying oxide film, a gate insulating film formed on the crystalline insulating film, and a gate electrode formed on the gate insulating film, a first interlayer dielectric is formed on the gate electrode, an electrode electrically connected to the source region or the drain region is formed on the first interlayer dielectric, a second interlayer dielectric is formed on the electrode, a display electrode electrically connected to the electrode is formed on the second interlayer dielectric, and the junction between the lightly doped region and the channel formation region corresponds to the end of the gate electrode. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The invention disclosed in this specification relates to an active matrix liquid crystal display device capable of performing color display.

  Liquid crystal display devices are used in a wide range of fields such as computers, calculators, and watches as lighter and more compact display devices than CRTs. The liquid crystal display device has the optical properties (interference, scattering, diffraction, optical rotation, absorption, etc.) of the liquid crystal material due to the change in the alignment state and phase transition of the liquid crystal molecules in response to the application of the external field (electric field, heat, etc.) of the liquid crystal material. The principle of operation is to change.

  As for the structure and driving method of a general liquid crystal display device, a liquid crystal material is sandwiched between two substrates, at least one of which has translucency and a distance of 1 to several tens of μm (hereinafter referred to as a liquid crystal panel). In other words, an electric field is applied to the liquid crystal material by the electrodes formed on both or one of the two substrates to control the alignment state of the liquid crystal molecules for each pixel in the substrate surface and transmit the liquid crystal panel. Image display is performed by controlling the amount of light. At this time, depending on which of the above optical properties is used, for example, a polarizing plate is provided on the outside of the liquid crystal panel, so that a configuration corresponding to the operation mode is adopted.

  Currently, the TN (twisted nematic) type or STN (super twisted nematic) type is widely used in liquid crystal display devices, and these are optical properties such as optical rotation of liquid crystal materials and interference of birefringent light, respectively. In any case, it is necessary to provide a polarizing plate.

  In addition, when displaying an image on the liquid crystal display device, various methods have been proposed in order to control the operation of many pixels simultaneously. Among them, active matrix driving is widely used as a method capable of high image quality and high density display. The purpose of this is to provide non-linear active elements (diodes, transistors, etc.) in each pixel so that each pixel is in an electrically independent relationship, eliminating interference of extra signals and realizing high image quality. To do. According to this method, each pixel can be viewed as a capacitor to which an electrical switch is connected. Accordingly, the charge can be injected / extracted to / from the pixel by turning on / off the switch as necessary. Further, when the switch is turned off, the charge is held in the pixel, so that it is possible to impart memory characteristics.

  Further, when performing color display in such a liquid crystal display device, a method using the principle of color mixing is currently most widely used. In general, there are subtractive and additive color mixing, and full color display is possible by using the three primary colors of cyan, magenta, yellow, red, blue and green. In a color LCD, the display color is controlled by changing the intensity of the three primary colors according to the applied voltage.

  In the case of a liquid crystal display device, as a color separation method, an RGB micro color filter is provided in the liquid crystal display device or three types of RGB panels are prepared, color separation is performed, and light is transmitted by the liquid crystal panel according to an image to be expressed. Modulation is performed, and color synthesis is performed again. In this regard, it largely depends on how the liquid crystal panel is used. In the case of a direct-view type liquid crystal display device, a micro color filter is often used. In the projection type, there are cases where three types of RGB panels are prepared for color display. Many.

  As a system widely used in the projection type liquid crystal light valve, there is a dichroic prism type liquid crystal projector. In this method, an optical system that separates white light of a light source into RGB components is formed by a dichroic mirror, and each liquid crystal display image of RGB single color is synthesized by a dichroic prism and enlarged and projected onto a screen by a projection lens. This method is advantageous in that the color synthesizing optical system is composed of a single prism, which is compact, easy to adjust, and shortens the back focus of the projection lens.

  In the dichroic mirror system, both color separation and color synthesis are configured by a dichroic mirror, and similarly, a liquid crystal display image of RGB single color is enlarged and projected onto a screen by a projection lens. Dichroic mirrors are suitable for mass production in terms of productivity costs. On the other hand, there are drawbacks such as an increase in overall dimensions and an increase in the back focus of the projection lens. However, there are many types that are currently in practical use.

  In recent years, a single-plate projection display using the dichroic mirror method has been proposed. This method is a combination of a single liquid crystal panel and three RGB dichroic mirrors, and is a small and inexpensive liquid crystal display.

(Problems of conventional technology)
In any of the above liquid crystal display devices, it is necessary to accurately control the luminance of each of the three primary colors in order to perform subtle color display. On the other hand, the drive system must be simple in order to reduce the cost of the device. However, in conventional liquid crystal display devices, when red, green, and blue are displayed, a phenomenon occurs in which the transmittance and contrast differ for each color. This correction complicates the drive circuit, increasing the cost and increasing the size of the device. Was causing.

  In view of the above, the present invention makes it possible to easily display a uniform transmittance and contrast regardless of a complicated driving method in a projection type liquid crystal display device regardless of a color, and thereby display a high image quality. An object of the present invention is to provide a possible liquid crystal display device.

In order to solve the above problems, the present invention provides a first insulating substrate having translucency,
A second insulating substrate facing the substrate;
In a liquid crystal display device having at least a liquid crystal material sandwiched between the first substrate and the second substrate,
The substrate intervals of pixels corresponding to red, green, and blue are different.

  The above configuration pays attention to the optimal thickness of the liquid crystal layer to transmit a predetermined wavelength region, and the intervals between the RGB liquid crystal panels are different, so that the image of each color finally projected is It features a uniform brightness and contrast.

  In addition, by utilizing this fact, it is possible to correct the color balance of the light source and the balance when using a dichroic mirror.

  As a configuration for forming an RGB image, it is useful to use a configuration in which RGB liquid crystal panels are integrated using the same substrate.

  In this configuration, since the horizontal operation control circuit and the vertical operation control circuit can be shared in each liquid crystal panel, the overall configuration can be simplified, and the apparatus itself can be miniaturized. There is.

  In such a configuration, the thickness of the insulating film formed in a region corresponding to each liquid crystal panel portion may be adjusted, and the thickness of the liquid crystal layer of each liquid crystal panel portion may be set as appropriate.

  An example of a configuration using the invention disclosed in this specification is shown in FIG. FIG. 1 shows a projection apparatus having a function of projecting RGB images individually from three independent optical systems onto a projection plane using three liquid crystal panels and synthesizing color images there.

  In the configuration shown in FIG. 1, (101, 102, 103) are liquid crystal panels for R (red), B (blue), and G (green), (104, 105, 106) are correction lenses, and (107, 108). 109) is a Fresnel lens, (110 to 115) is a condensing lens, (116, 117) dichroic mirrors for R and B, (118) is a reflector (total reflection), and (119) is a cold mirror. , (120) is a metal halide lamp, and (121) is a UV / IR cut mirror.

  FIGS. 5 to 7 show the configuration shown in FIG. 1 as viewed from other accuracies.

  FIG. 2 is a cross-sectional view of the liquid crystal panel. (201, 202) is a substrate, (203, 204) is an electrode, (205) is an alignment film, (206) is a spacer, (207) is a sealing agent, and (208) is a liquid crystal material.

  For the first and second substrates, a material having translucency and a certain degree of strength against external force, for example, an inorganic material such as glass or quartz is used. When a TFT is formed on a substrate, non-alkali glass or a quartz substrate is used. For the purpose of reducing the weight of the liquid crystal panel, a film having low birefringence, such as PES (polyethylene sulfate), can also be used.

  The liquid crystal material may be driven by a multiplex method or an active matrix method. In the multiplex method, only two types of display electrodes and reference electrodes need be formed on the first substrate. However, in the case of the active matrix method, other non-linear elements such as thin film transistors (TFTs) A diode is formed for each pixel. As the TFT, a transistor using amorphous silicon or poly (polycrystalline) silicon as an active layer can be used.

  As a further advanced configuration, there is a configuration in which the peripheral drive circuit is formed of thin film transistors and integrated on a substrate. Since this configuration is obtained as an integrated structure in which the pixel region and the peripheral circuit region are integrated on the substrate, the liquid crystal panel can be more easily used.

  Further, a black matrix is formed in a portion unrelated to display for improving display characteristics. As the black matrix, it is possible to use a metal such as Cr or a material in which a black substance is dispersed in a transparent substance in order to prevent a decrease in contrast due to irregular reflection inside the liquid crystal display device. In particular, an inorganic material such as glass or quartz or an organic material such as a resin can be used as the transparent substance, but a resin material is preferably used in terms of ease of manufacture. As the resin material, an acrylic material or the like can be used. As the black substance, carbon black or a pigment can be used.

  As the liquid crystal material to be used, a material exhibiting nematic, cholesteric, or smectic properties can be used.

  The substrate subjected to the alignment treatment in this manner is arranged so that the alignment treatment surface or the surface on which the TFT, the transparent electrode or the like is formed faces each other, and a liquid crystal material is sandwiched between the opposing substrates. Spacers or the like are dispersed on the pair of substrates so that the distance between the substrates is constant. The spacer used has a diameter of 1 to 10 μm. The pair of substrates is fixed with an epoxy adhesive or the like. The adhesive pattern is formed on the outer periphery of the substrate so that the pixel region and the peripheral drive circuit region are on the inside.

(Function)
The transmitted light intensity T of the liquid crystal display device can be expressed as follows.

ここで、ｕは、

であり、θはツイスト角（≠π／２）である。Δｎは液晶材料の屈折率異方性、ｄはセル厚、λは光の波長である。数１が０になるときの条件として、ｕ＝４ｍ−１（ｍは整数）である必要がある。またＴは波長及びセル厚に依存することが分かる。従って、各三原色ようにセル厚が一定なパネルを作製した場合、すべての三原色で暗状態が同時には得られない。すべての三原色で同時に暗状態を得るためには各色に応じて異なったセル厚にしなければならない。

Where u is

And θ is the twist angle (≠ π / 2). Δn is the refractive index anisotropy of the liquid crystal material, d is the cell thickness, and λ is the wavelength of light. It is necessary that u = 4m−1 (m is an integer) as a condition when the number 1 becomes 0. It can also be seen that T depends on the wavelength and cell thickness. Therefore, when a panel having a constant cell thickness is produced for each of the three primary colors, dark states cannot be obtained simultaneously for all three primary colors. To obtain a dark state for all three primary colors at the same time, the cell thickness must be different for each color.

  In the present invention, in order not to reduce the viewing angle, the cell thickness and Δn of the liquid crystal material were adjusted so that u = √3 or √15.

と変形できる。飽和電圧が印加されると、Ｔ（ｄ）＝１となる。従って数１、数３はコントラストの逆数となる。 Number 1 is the following number 3

And can be transformed. When a saturation voltage is applied, T (d) = 1. Therefore, Equations 1 and 3 are reciprocal contrasts.

  According to the present invention, a contrast of 50 or more can be obtained in the visible light region.

  As described above in detail, in the projection type liquid crystal display device, the liquid crystal panel having different cell thicknesses for each RGB color is used, so that even if any color is displayed, uniform transmittance and contrast display are complicated. It can be easily performed regardless of the driving method, and high-quality display is possible.

  A projection type liquid crystal display device and a manufacturing method thereof in this embodiment will be described below. Three liquid crystal panels were produced, one for each of the three primary colors. FIG. 1 shows a liquid crystal display device of this example.

  FIG. 2 shows a liquid crystal panel. First, transparent electrodes were formed on glass substrates (201, 202) as first and second insulating substrates. Next, an alignment film was formed on each substrate. For the alignment film, low-temperature firing type polyimide AL3046 (manufactured by Nissan Chemical Co., Ltd.) was applied by 800 mm by a known spin coating method or the like, and then fired at 160 ° C. Next, for the alignment treatment of the liquid crystal material, a known rubbing treatment was performed on each substrate.

Next, spacers were sprayed on the rubbed substrate in a dry or wet manner. As the spacer, a spherical one made of resin such as SiO ₂ (silicon oxide) or plastic was used. In order to change the cell thickness according to the three primary colors, a spacer of 5.4 μm was used for the red panel, 4.6 μm for the green panel, and 3.8 μm for the blue panel.

  Next, a liquid crystal cell was produced using these substrates. First, a sealant was printed on the first or second substrate of each color panel. As the sealant, an adhesive containing a thermosetting epoxy resin was used. Thereafter, the opposing substrates were overlapped so that the rubbing directions were orthogonal to each other between the pair of substrates, and the sealant was cured while pressing the pair of substrates with a hot press or the like to obtain a liquid crystal cell.

  Next, a liquid crystal material was injected into the liquid crystal cell by a vacuum injection method or the like. The liquid crystal material used in this example was a nematic liquid crystal ZLI-4792 manufactured by Merck (trade name). The threshold value of this liquid crystal material was 2V.

  A dichroic mirror type was used for the optical system in this example. The RGB panel was installed at the position of the liquid crystal panel shown in FIG. This projection type liquid crystal display device can display a high-definition image having a contrast of 50 or more.

  A method for manufacturing a substrate of a liquid crystal display device using the active matrix circuit in this embodiment will be described below. The liquid crystal display device of this example was a single plate type rear projection. In addition, the liquid crystal panel of the liquid crystal display device of this example is a monolithic active matrix circuit in which a peripheral drive circuit is also formed in the substrate. This production process will be described with reference to FIG. This step is for the low temperature polysilicon process.

  The left side of FIG. 3 shows the TFT fabrication process of the drive circuit, and the right side shows the TFT fabrication process of the active matrix circuit.

  First, a silicon oxide film having a thickness of 1000 to 3000 mm was formed as a base oxide film (302) on a glass substrate (301) as a first insulating substrate. As a method for forming this silicon oxide film, a sputtering method or a plasma CVD method in an oxygen atmosphere may be used.

  Thereafter, an amorphous silicon film was formed to 300 to 1500 mm, preferably 500 to 1000 mm, by plasma CVD or LPCVD. Then, thermal annealing was performed at a temperature of 500 ° C. or higher, preferably 500 to 600 ° C., to crystallize the silicon film or improve the crystallinity. After crystallization by thermal annealing, light (laser or the like) annealing may be performed to further increase crystallization. Further, at the time of crystallization by thermal annealing, as described in JP-A-6-244103 and JP-A-6-244104, an element (catalytic element) that promotes crystallization of silicon such as nickel may be added.

Next, the silicon film is etched to activate the TFT active layer (303) (for p-channel TFT) and (304) (for N-channel TFT) in the driver circuit on the island and the TFT (pixel TFT) in the matrix circuit Layer (305) was formed. Further, a silicon oxide gate insulating film (306) having a thickness of 500 to 2000 mm was formed by sputtering in an oxygen atmosphere. As a method for forming the gate insulating film, a plasma CVD method may be used. When forming a silicon oxide film by plasma CVD, it was preferable to use dinitrogen monoxide (N ₂ O) or oxygen (O ₂ ) and monosilane (SiH ₄ ) as a source gas.

  Thereafter, aluminum having a thickness of 2000 to 6000 mm was formed on the entire surface of the substrate by sputtering. Here, aluminum may contain silicon, scandium, palladium, or the like in order to prevent hillocks from being generated by a subsequent thermal process. Then, this is etched to form gate electrodes (307, 308, 309) (FIG. 3A).

Thereafter, phosphorus is implanted into all island-like active layers by ion doping in a self-aligning manner using the gate electrode as a mask and phosphine (PH ₃ ) as a doping gas. The dose is 1 × 10 ^{12 to} 5 × 10 ¹³ atoms / cm ² .
As a result, weak N-type regions (310, 311 and 312) are formed. (Fig. 3 (B))

  Next, the photoresist mask (313) covering the active layer of the P-channel TFT and the active layer (305) of the pixel TFT are covered in parallel to the gate electrode up to a portion 3 μm away from the end of the gate electrode (309). A photoresist mask (314) is formed.

Then, phosphorus is implanted again using phosphine as a doping gas by ion doping. The dose is 1 × 10 ^{14 to} 5 × 10 ¹⁵ atoms / cm ² . As a result, strong N type regions (source, drain) (315, 316) are formed. Of the weak N-type region (312) of the active layer (305) of the pixel TFT, the region (317) covered with the mask (314) remains weak N-type because phosphorus is not implanted in this doping. Become. (Figure 3 (C))

Next, the active layer (304, 305) of the N-channel TFT is covered with a photoresist mask (318), and diborane (B ₂ H ₆ ) is used as a doping gas to form the island-like region (303). Boron is injected. The dose is 5 × 10 ¹⁴ to 8 × 10 ¹⁵ atoms / cm ² .

  In this doping, since the dose of boron exceeds the dose of phosphorus in FIG. 3C, the weak N-type region (310) formed previously is inverted to a strong P-type region (319).

  By the above doping, strong N-type regions (source / drain) (315, 316), strong P-type regions (source / drain) (319), and weak N-type regions (low-concentration impurity regions) (317) are formed. . In this embodiment, the width x of the low-concentration impurity region (317) is about 3 μm. (Fig. 3 (D))

  Thereafter, thermal annealing was performed at 450 to 850 ° C. for 0.5 to 3 hours to recover the damage due to doping, activate the doping impurities, and recover the crystallinity of silicon. Thereafter, a silicon oxide film having a thickness of 3000 to 6000 was formed as an interlayer insulator (320) on the entire surface by plasma CVD. This may be a silicon nitride film or a multilayer film of a silicon oxide film and a silicon nitride film. Then, the interlayer insulating film (320) was etched by wet etching or dry etching to form contact holes in the source / drain.

  Then, an aluminum film having a thickness of 2000 to 6000 mm or a multilayer film of titanium and aluminum is formed by sputtering. This was etched to form peripheral circuit electrodes / wirings (321, 322, 323) and pixel TFT electrodes / wirings (324, 325). Further, a silicon nitride film (326) having a thickness of 1000 to 3000 mm was formed as a passivation film by plasma CVD, and this was etched to form an interlayer film. Further, a 1200-thick ITO (327) film was formed thereon as a display electrode, and was patterned to have the same pattern as the display electrode in Example 1.

  Further, a silicon nitride film (328) having a thickness of 1000 to 3000 mm is formed as a passivation film by plasma CVD, and 1200 mm of ITO (not shown) is formed thereon as a reference electrode. Patterning was performed so as to be the same pattern as the reference electrode. (Figure 3 (E))

  Next, in FIG. 2, a black matrix was formed on the opposing substrate 204 (not shown). The black matrix used here is made of Cr, has a thickness of 1200 mm, and is patterned into a desired shape by a known photolithography method. Next, a color filter was formed (not shown). For the color filter, a material in which pigments showing R, G, and B colors are dispersed in a solvent such as ethylene glycol and monoethyl ether acetate was repeatedly applied, patterned, and cured (baked) for each color to form a micro color filter. The film thickness of each color was 1.7 μm.

  Further, an overcoat agent (planarizing film) made of an acrylic resin was formed thereon. The overcoat agent is initially formed on the entire surface with a thickness of 1 μm. Next, it is formed with a thickness of 0.8 μm. Further, the overcoat agent is etched only for the R (red) portion by a known patterning technique. Next, an overcoat agent is again applied with a thickness of 0.8 μm, and only the R and G portions are selectively etched. As a result, the film thickness differs between RGB. For example, in the portion R, the total thickness of the color filter and the overcoat film is 2.7 μm. The portion G is 3.5 μm. Further, the portion B is 4.3 μm.

  Next, a transparent electrode 204 made of ITO was formed on the entire surface. A transparent electrode 203 was formed on the counter substrate 201. Next, an alignment film 205 made of polyimide was formed as an alignment film on the substrates 201 and 202.

  Next, the alignment film 205 was rubbed by a normal method. At this time, the rubbing was performed in such a direction that the upper and lower substrates form an angle of 90 °.

  Next, spacers 206 made of silicon oxide having a diameter of 3.8 μm were dispersed on the substrate coated with the alignment film (not shown).

  In the liquid crystal panel thus manufactured, the thickness of the liquid crystal layer in the region corresponding to RGB is R of 5.4 μm, G of 4.6 μm, and B of 3.8 μm.

Next, a sealant 207 was printed on the substrate 201, and the substrates 201 and 204 were overlapped and fixed. At this time, the sealing material was printed near the outer periphery of the substrate so that the pixel region and the peripheral drive circuit region were inside. Next, a liquid crystal material 208 was injected into the cell by a vacuum injection method. The liquid crystal material used was a nematic liquid crystal ZLI-4792 (trade name) manufactured by Merck.
Thus, the liquid crystal panel of FIG. 2 was formed.

  FIG. 4 shows a schematic cross-sectional view of the rear projection of this example formed in this way. 401 is a halogen lamp, 402 is a condensing optical system, 403 is a liquid crystal panel, 404 is a reflector, 405 is a projection lens, and 407 is a screen.

  The projection type liquid crystal display device can display a good image.

1 shows an outline of a liquid crystal display device in Example 1 of the present invention. 1 shows a schematic cross section of a liquid crystal panel in Example 1 of the present invention. 5 shows a cross section of a pixel TFT and a peripheral drive circuit of a liquid crystal display device in Example 2 of the present invention. The cross-sectional outline of the liquid crystal display device in Example 2 of this invention is shown. The outline | summary which looked at the liquid crystal display device in Example 1 from another angle is shown. The outline | summary which looked at the liquid crystal display device in Example 1 from another angle is shown. The outline | summary which looked at the liquid crystal display device in Example 1 from another angle is shown.

Explanation of symbols

101, 102, 103 Liquid crystal panel 104, 105, 106 Dichroic mirror 107 Reflector 108 Halogen lamp 109 Fresnel lens 110 Projection lens 201, 202 Substrate 203, 204 Transparent electrode 205 Alignment film 206 Spacer 207 Sealant 208 Liquid crystal material 301 Substrate 302 Bottom Base film (silicon oxide)
303, 304, 305 Active layer 306 Gate insulating film 307, 308, 309 Gate insulating film / gate lines 310, 311, 312 Weak N-type region 313, 314 Photoresist mask 315, 316 Strong N-type region (source / drain)
317 Low-concentration impurity region 318 Photoresist mask 319 Strong P-type region (source / drain)
320 Interlayer insulating films 321 to 325 Peripheral drive circuit, pixel TFT electrode / wiring 326, 328 Silicon nitride film 327 Display electrode (ITO)
401 Lamp 402 Condensing optical system 403 Liquid crystal panel 404 Mirror 405 Projection lens 406 Screen

Claims (14)

A display device having a liquid crystal panel in which a pixel region and a peripheral drive circuit region are formed on the same substrate,
The pixel region and the peripheral driver circuit region have thin film transistors,
The thin film transistor formed in the pixel region is
A crystalline silicon film having a source region, a drain region, a low-concentration impurity region, and a channel formation region formed over the base oxide film;
A gate insulating film formed on the crystalline silicon film;
A gate electrode formed on the gate insulating film,
A first interlayer insulating film is formed on the gate electrode,
An electrode electrically connected to the source region or the drain region is formed on the first interlayer insulating film,
A second interlayer insulating film is formed on the electrode,
A display electrode electrically connected to the electrode is formed on the second interlayer insulating film,
A display device, wherein a junction between the low-concentration impurity region and the channel formation region coincides with an end portion of the gate electrode. A display device having a liquid crystal panel in which a pixel region and a peripheral drive circuit region are formed on the same substrate,
The pixel region and the peripheral driver circuit region have thin film transistors,
The thin film transistor formed in the pixel region is
A crystalline silicon film having a source region, a drain region, a low-concentration impurity region, and a channel formation region formed over the base oxide film;
A gate insulating film formed on the crystalline silicon film;
A gate electrode formed on the gate insulating film,
A first interlayer insulating film is formed on the gate electrode,
An electrode electrically connected to the source region or the drain region is formed on the first interlayer insulating film,
A second interlayer insulating film is formed on the electrode,
A display electrode electrically connected to the electrode is formed on the second interlayer insulating film,
The junction between the low concentration impurity region and the channel formation region coincides with the end of the gate electrode,
A display device, wherein N-channel and P-channel thin film transistors are formed in the peripheral driver circuit region. A display device that obtains a color image by projecting images from three liquid crystal panels through an optical system,
Each of the three liquid crystal panels has a pixel region and a peripheral driving circuit region formed on the same substrate,
The pixel region and the peripheral driver circuit region have thin film transistors,
The thin film transistor formed in the pixel region is
A crystalline silicon film having a source region, a drain region, a low-concentration impurity region, and a channel formation region formed over the base oxide film;
A gate insulating film formed on the crystalline silicon film;
A gate electrode formed on the gate insulating film,
A first interlayer insulating film is formed on the gate electrode,
An electrode electrically connected to the source region or the drain region is formed on the first interlayer insulating film,
A second interlayer insulating film is formed on the electrode,
A display electrode electrically connected to the electrode is formed on the second interlayer insulating film,
A display device, wherein a junction between the low-concentration impurity region and the channel formation region coincides with an end portion of the gate electrode. A display device that obtains a color image by projecting images from three liquid crystal panels through an optical system,
Each of the three liquid crystal panels has a pixel region and a peripheral driving circuit region formed on the same substrate,
The pixel region and the peripheral driver circuit region have thin film transistors,
The thin film transistor formed in the pixel region is
A crystalline silicon film having a source region, a drain region, a low-concentration impurity region, and a channel formation region formed over the base oxide film;
A gate insulating film formed on the crystalline silicon film;
A gate electrode formed on the gate insulating film,
A first interlayer insulating film is formed on the gate electrode,
An electrode electrically connected to the source region or the drain region is formed on the first interlayer insulating film,
A second interlayer insulating film is formed on the electrode,
A display electrode electrically connected to the electrode is formed on the second interlayer insulating film,
The junction between the low concentration impurity region and the channel formation region coincides with the end of the gate electrode,
A display device, wherein N-channel and P-channel thin film transistors are formed in the peripheral driver circuit region. In any one of Claims 1 thru | or 4,
The display device, wherein the display electrode is made of ITO. In any one of Claims 1 thru | or 5,
The display device, wherein the first interlayer insulating film is a silicon oxide film, a silicon nitride film, or a multilayer film of a silicon oxide film and a silicon nitride film. In any one of Claims 1 thru | or 6,
The display device, wherein the second interlayer insulating film is a silicon nitride film. A rear projection type liquid crystal display device having a liquid crystal panel in which a pixel region and a peripheral drive circuit region are formed on the same substrate,
The pixel region and the peripheral driver circuit region have thin film transistors,
The thin film transistor formed in the pixel region is
A crystalline silicon film having a source region, a drain region, a low-concentration impurity region, and a channel formation region formed over the base oxide film;
A gate insulating film formed on the crystalline silicon film;
A gate electrode formed on the gate insulating film,
A first interlayer insulating film is formed on the gate electrode,
An electrode electrically connected to the source region or the drain region is formed on the first interlayer insulating film,
A second interlayer insulating film is formed on the electrode,
A display electrode electrically connected to the electrode is formed on the second interlayer insulating film,
A rear projection liquid crystal display device, wherein a junction between the low-concentration impurity region and the channel formation region coincides with an end of the gate electrode. A rear projection type liquid crystal display device having a liquid crystal panel in which a pixel region and a peripheral drive circuit region are formed on the same substrate,
The pixel region and the peripheral driver circuit region have thin film transistors,
The thin film transistor formed in the pixel region is
A crystalline silicon film having a source region, a drain region, a low-concentration impurity region, and a channel formation region formed over the base oxide film;
A gate insulating film formed on the crystalline silicon film;
A gate electrode formed on the gate insulating film,
A first interlayer insulating film is formed on the gate electrode,
An electrode electrically connected to the source region or the drain region is formed on the first interlayer insulating film,
A second interlayer insulating film is formed on the electrode,
A display electrode electrically connected to the electrode is formed on the second interlayer insulating film,
The junction between the low concentration impurity region and the channel formation region coincides with the end of the gate electrode,
2. A rear projection type liquid crystal display device, wherein N-channel and P-channel thin film transistors are formed in the peripheral driver circuit region. A rear projection type liquid crystal display device for obtaining a color image by projecting images from three liquid crystal panels through an optical system,
Each of the three liquid crystal panels has a pixel region and a peripheral driving circuit region formed on the same substrate,
The pixel region and the peripheral driver circuit region have thin film transistors,
The thin film transistor formed in the pixel region is
A crystalline silicon film having a source region, a drain region, a low-concentration impurity region, and a channel formation region formed over the base oxide film;
A gate insulating film formed on the crystalline silicon film;
A gate electrode formed on the gate insulating film,
A first interlayer insulating film is formed on the gate electrode,
An electrode electrically connected to the source region or the drain region is formed on the first interlayer insulating film,
A second interlayer insulating film is formed on the electrode,
A display electrode electrically connected to the electrode is formed on the second interlayer insulating film,
A rear projection liquid crystal display device, wherein a junction between the low-concentration impurity region and the channel formation region coincides with an end of the gate electrode. A rear projection type liquid crystal display device for obtaining a color image by projecting images from three liquid crystal panels through an optical system,
Each of the three liquid crystal panels has a pixel region and a peripheral driving circuit region formed on the same substrate,
The pixel region and the peripheral driver circuit region have thin film transistors,
The thin film transistor formed in the pixel region is
A crystalline silicon film having a source region, a drain region, a low-concentration impurity region, and a channel formation region formed over the base oxide film;
A gate insulating film formed on the crystalline silicon film;
A gate electrode formed on the gate insulating film,
A first interlayer insulating film is formed on the gate electrode,
An electrode electrically connected to the source region or the drain region is formed on the first interlayer insulating film,
A second interlayer insulating film is formed on the electrode,
A display electrode electrically connected to the electrode is formed on the second interlayer insulating film,
The junction between the low concentration impurity region and the channel formation region coincides with the end of the gate electrode,
2. A rear projection type liquid crystal display device, wherein N-channel and P-channel thin film transistors are formed in the peripheral driver circuit region. In any one of Claims 8 thru | or 11,
The rear projection type liquid crystal display device, wherein the display electrode is made of ITO. In any one of claims 8 to 12,
The rear projection type liquid crystal display device, wherein the first interlayer insulating film is a silicon oxide film, a silicon nitride film, or a multilayer film of a silicon oxide film and a silicon nitride film. In any one of Claims 8 thru | or 13,
The rear projection type liquid crystal display device, wherein the second interlayer insulating film is a silicon nitride film.

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