Electro-optical device, projection-type display device, electronic device, and manufacturing method of the electro-optical device

In the electro-optical device, a pillar-shaped protrusion is formed on an insulating film (a first insulating film) provided below a pixel electrode in the downward direction, and thus a conduction section of a second electrode layer (a conductive layer) overlaps the highest surface of the pillar-shaped protrusion. An inter-layer insulating film (a second insulating film) is provided between the second electrode layer and the pixel electrode, but the conduction section is exposed on a surface of the inter-layer insulating film. For this reason, the pixel electrode is electrically connected to the conduction section, when the pixel electrode is laminated on the inter-layer insulating film.

BACKGROUND

1. Technical Field

The present invention relates to an electro-optical device including a liquid crystal device, a projection-type display device, and an electronic device, and more particularly to a peripheral configuration of pixel electrodes of the electro-optical device.

2. Related Art

The pixels with pixel electrodes are arranged in the matrix on an element substrate for use in the electro-optical device, such as a liquid crystal device and an organic electroluminescence device, and the pixel electrode is electrically connected to a conductive layer beneath the pixel electrode in the downward direction, through a contact hole formed in an insulating film (refer to JP-A-2006-317903).

The contact hole in this electro-optical device is large in horizontal size, and the electro-optical device decreases in display grade. For example, the contact hole in a liquid crystal device is so large in horizontal size that a pixel electrode has a large depression and elevation on the surface. This prevents an oriented film from being formed in a suitable manner. Furthermore, in a transmission-type liquid crystal device, an amount of display light decreases because light cannot pass through the contact hole. Furthermore, an area of the depression and elevation does not contribute to display, because the reflection direction of light is in disorder there, when the pixel electrode has the large depression and elevation on the surface in a reflection-type liquid crystal device.

On the other hand, a configuration is commonly employed that buries a plug in a contact hole in an inter-layer insulating film, and electrically connects the pixel electrode and an electrode beneath the pixel electrode (that is, in the downward direction), through this plug buried in the contact hole in the inter-layer insulating film (refer to JP-A-2011-64849). With this configuration, the contact hole is made smaller in horizontal size, thereby preventing the large depression and elevation from being formed on the surface of the pixel electrode.

However, in the conducting structure that uses the plug, it is necessary to additionally prepare a metal material, which is not in common use for the electro-optical device, such as tungsten, in order to form the plug. This increases the manufacturing cost. Furthermore, it is necessary to perform a step of sputtering metal to thicken a metal film for the plug and a step of smoothing an inter-layer insulating film by a chemical machinery polishing method, until the contact hole is filled. The sputtering step of these steps decreases productivity because it takes too much time to sputter metal to thicken the metal film for the plug.

SUMMARY

An advantage of some aspects of the invention is to provide an electro-optical device that has a conduction portion of a pixel electrode, not occupying a large area, formed by using a film formed for other purposes, and therefore has not a large depression and elevation on a surface of the pixel electrode, a projection-type display device, and an electronic device.

According to an aspect of the invention, there is provided a plurality of pixel electrodes provided over one side of a substrate, a first insulating film, provided between the substrate and the plurality of pixel electrodes, including pillar-shaped protrusions protruding toward the pixel electrodes in positions overlapping the pixel electrodes when viewed from above, a conductive layer, provided between the first insulating film and the pixel electrodes, including a conduction section overlapping highest surfaces of the pillar-shaped protrusions when viewed from above, and a second insulating film, provided between the conductive layer and the pixel electrodes, exposing one side of the conduction section, the one side in the direction of the pixel electrode, wherein the pixel electrodes are deposited on one side of the second insulating film, the one side in the direction of the pixel electrode, thereby resulting in the pixel electrode being electrically connected to the conduction section.

According to another aspect of the invention, there is provided a method of manufacturing an electro-optical device including forming a first insulating film over one side of a substrate, forming a pillar-shaped protrusion protruding upward on the first insulating film by partly etching a surface of the first insulating film, forming a conductive layer on the first insulating film including an area for forming the pillar-shaped protrusion, forming a second insulating film on the conductive layer, exposing as a conduction section a portion overlapping the highest surface of the pillar-shaped protrusion when viewed from above, in the conductive layer, by removing the second insulating film in the downward direction, and forming a pixel electrode on the second insulating film including the exposed portion of the conduction section.

The pillar-shaped protrusions, protruding toward the pixel electrodes in a position overlapping the pixel electrodes are formed on the first insulating film provided between the pixel electrodes and the substrate. These highest surfaces of the pillar-shaped protrusions overlap the conduction section of the conductive layer when viewed from above. Furthermore, the second insulating film is provided between the conductive layer and the pixel electrode, but the conduction section is exposed on the surface of the second insulating film in the direction of the pixel electrode. For this reason, the pixel electrodes are electrically connected to the conduction section, when the pixel electrodes are laminated on the second insulating film. For this reason, a contact portion is smaller in horizontal size, and the pixel electrode does not have a large depression and elevation on the surface, compared to the structure that connects the pixel electrode and the conductive layer by using a contact hole formed in the insulating film. Furthermore, the pixel electrode is electrically connected by using a film formed for other purposes in the electro-optical device, such as a conductive layer and an insulating film, and special metal for a plug does not need to be thickly deposited.

The surface of the conduction section in the direction of the pixel electrode and the surface of the second insulating film in the direction of the pixel electrode may make up one plane surface in succession. In this configuration, the pixel electrode is made to be formed on the plane surface.

The electro-optical device may further include a capacity electrode layer, provided between the conductive layer and the substrate, and a dielectric layer, provided between the capacity electrode layer and the conductive layer, with a storage capacitance being formed from the capacity electrode layer, the dielectric layer, and the conductive layer. That is, the pixel electrode may be electrically connected by using an electrode layer (the conductive layer) making up the storage capacitance.

In the electro-optical device, the first insulating film may be provided between the capacity electrode layer and the conductive layer, and an opening may be provided in an area where the capacity electrode layer and the conductive layer overlap each other when viewed from above. In this configuration, although the dielectric layer is thin, the short circuit between the highest portion of the first insulating film and the capacity electrode layer may be prevented by the first insulating film.

In the electro-optical device, in the pixel electrodes, the conductive layer and the capacity electrode layer may be provided in an area that overlaps an area between the adjacent pixel electrodes when viewed from above. In this configuration, since the conductive layer is positioned nearer the pixel electrode than the capacity electrode layer, liquid crystal orientation is not disturbed by potential occurring between the pixel electrode and the capacity electrode layer.

In the electro-optical device, the pillar-shaped protrusion may be provided in a position that overlaps the capacity electrode layer when viewed from above. In this configuration, since the pillar-shaped protrusion and the conduction section are provided at a high level, a film-thick portion of the capacity electrode layer may be electrically connected to the pixel electrode, in an easy manner.

The electro-optical device for use in a liquid crystal device, may have a configuration that holds a liquid crystal layer between the substrate and an opposite substrate opposite to the substrate.

The electro-optical device to which an aspect of the invention is applied may be used in a variety of display devices for a variety of electronic devices, such as a direct-view display device. Furthermore, the electro-optical device to which the aspect of the invention is applied may be used in a projection-type display device. This projection-type display device includes a light source unit emitting light to be incident on the electro-optical device, and a projection optical system projecting light modulated by the electro-optical device.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

The embodiments are now described with reference to the accompanying drawings. Among a variety of electro-optical devices, the liquid crystal device and a method of manufacturing the liquid crystal device are described, focusing on the case where the aspect of the invention is applied in connecting electrically a pixel electrode9aand a second electrode layer7a(a conductive layer). Furthermore, layers and members are enlarged to recognizable degrees in each of the figures, and thus vary in scale from figure to figure. Furthermore, the roles of a source and a drain are in practice interchanged when a direction of electrical current flowing through a pixel transistor is reversed. However, one side (a source drain area in the direction of the pixel), to which the pixel electrode is electrically connected, is defined as a drain, and the other side (a source drain area in the direction of the data line), to which a data line is electrically connected, is defined as a source. Furthermore, when describing a layer formed on an element substrate, the term ‘the upward direction’ or ‘the surface direction’ is used to mean the direction opposite to the direction in which the substrate body of the element substrate is positioned (the direction of the opposite substrate), and the term ‘the downward direction’ is used to mean the direction in which the substrate body of the element substrate is positioned (the direction opposite to the direction in which the opposite substrate is positioned).

Description of Electro-Optical Device (Liquid Crystal Device)

Whole Configuration

FIG. 1is a block diagram illustrating an electrical configuration of the electro-optical device to which an aspect of the invention is applied.FIG. 1is only an electrical block diagram and therefore schematically shows a layout, such as a direction in which a capacity electrode layer extends.

As shown inFIG. 1, the electro-optical device100(a liquid crystal device) according to the invention includes a liquid crystal panel100pof a TN (Twisted Nematic) mode and a VA (Vertical Alignment) mode. The liquid crystal panel100phas an image display area10a(a pixel area) in the middle, where a plurality of pixels100aare arranged in the matrix. In the liquid crystal panel100p, a plurality of data lines6aand a plurality of scan lines3aextend in rows and columns within the image display area10aon the element substrate10(refer toFIGS. 2A and 2B), which is described below, and the pixels100aare formed in a position corresponding to an intersection where the data line6aand the scan line3across each other. A pixel transistor30, made from an effect type transistor and a pixel electrode9ato be described below, is formed on each of the plurality of the pixels100a. The data line6ais electrically connected to a source of the pixel transistor30. The scan line3ais electrically connected to a gate of the pixel transistor30. The pixel electrode9ais electrically connected to a drain of the pixel transistor30.

A scan line drive circuit104and a data line drive circuit101are provided outside of the image display area10aon the element substrate10. The data line drive circuit101is electrically connected to each of data lines6aand sends an image signal, received from an image process circuit, sequentially to each of the data lines6a. The scan line drive circuit104is electrically connected to each of scan lines3aand sequentially sends a scan signal to each of the scan lines3a.

The pixel electrode9ain each pixel100ais opposite to a common electrode formed on the opposite substrate20(refer toFIGS. 2A and 2B) to be described below, through a liquid crystal layer, and makes up the liquid crystal capacitance50a. Furthermore, a storage capacitance55is added to each pixel100a, in parallel with the liquid crystal capacitance50a, to prevent a change in an image signal retained in the liquid crystal capacitance50a. In the embodiment, a first electrode layer5astraddling the plurality of pixels100ais formed as an electrode capacity layer to make up the storage capacitance55. In the embodiment, the first electrode layer5ais electrically connected to a common potential line5cto which common potential Vcom is applied.

Configuration of Liquid Crystal Panel100p

FIGS. 2A and 2Bare explanatory views of the liquid crystal panel100pfor use in the electro-optical device100to which the aspect of the invention is applied.FIG. 2Ais a top view of the liquid crystal panel100pand elements of the liquid crystal panel100p, when viewed from the opposite substrate.FIG. 2Bis a cross sectional view of the liquid crystal panel100pand the elements of the liquid crystal panel100pcut along line IIB-IIB.

As shown inFIGS. 2A and 2B, the liquid crystal panel100pis made by attaching an element substrate10(an element substrate for use in the electro-optical device) and the opposite substrate20to each other, with a given distance in between, by using a sealant107provided in a frame shape along the edge of the opposite substrate20. The sealant107is an adhesive made of a material such as a photopolymer or a thermosetting resin. The sealant107is mixed with a gap-maintaining material, such as a glass fiber or a glass bead to maintain the given distance between the two substrates.

In this configuration, in the liquid crystal panel100p, the element substrate10and the opposite substrate20are all in the rectangular form, and thus the image display area10a, as described referring toFIG. 1, is provided in the rectangular form in the near middle of the liquid crystal panel100p. Accordingly, the sealant107is provided in the near rectangular form, and a periphery area10bin the near rectangular form is provided in the picture frame between an inner peripheral line of the sealant107and an outer peripheral line of the image display area10a. In the element substrate10, a data line drive circuit101and a plurality of terminals102are formed along one outside part of the element substrate10, but outside of the image display area10a, and a scan line drive circuit104is formed along the other outside part adjacent to the one outside part. A flexible wiring substrate (not shown) is connected to the terminal102. A variety of potential and a variety of signals are input to the element substrate10through the flexible wiring substrate.

The pixel transistor30, described referring toFIG. 1, and the pixel electrode9a, electrically connected to the pixel transistor30, are formed in the matrix on the image display area10a, on one side10sof the one side10sand other side10tof the element substrate10, and an oriented film16is formed on the pixel electrode9a, in the upward direction. This is described below in more detail.

Furthermore, a dummy pixel electrode9b(refer toFIG. 2B), which was formed at the same time as the pixel electrode9a, is formed in a peripheral area10bon one side10sof the element substrate10. The dummy pixel electrode9bmay be electrically connected to a dummy pixel transistor, or direct to wiring without the dummy pixel transistor being provided. Otherwise, the dummy pixel electrode9bmay be in a floating state. In the floating state, potential is not applied to the dummy pixel electrode9b. This dummy pixel electrode9bcontributes to reducing height positions of both of the image display area10aand the peripheral area10bto the same level and to smoothing the surface on which to form an oriented film16, when smoothing the surface on which to form the oriented film16on the element substrate10. Furthermore, disturbance of the orientation of liquid crystal molecules may be prevented in the peripheral end of the image display area10a, when the dummy pixel electrode9bis set to given potential.

A common electrode21is formed on one side of the opposite substrate20, that is, on the one side opposite to the element substrate10. An oriented film26is formed on the common electrode21. The common electrode21is formed in such a manner as to straddle almost the entire surface of the opposite substrate20, or the plurality of the pixels100aas a plurality of strip electrodes. Furthermore, a light-shielding layer108is formed beneath the common electrode21, in the downward direction (that is, in the direction of opposing the element substrate10), on one side of the opposite substrate20. In the embodiment, the light-shielding layer108is formed on the picture frame extending along the outer peripheral line of the image display area10a, and has a function of forming a border. At this point, the outer peripheral line of the light-shielding layer108is located a given distance away from the inner peripheral line of the sealant107, and thus the light-shielding layer108and the sealant107do not overlap each other. The light-shielding layer108may be formed as a black matrix part in, for example, an area overlapping an inter-pixel area interposed between the adjacent pixel electrodes9a, on the opposite substrate20.

In this configuration of the liquid crystal panel100p, an inter-substrate conduction electrode109for electrical conduction between the element substrate10and the opposite substrate20, is formed in an area overlapping a corner part of the opposite substrate20, outside of the sealant107, on the element substrate10. The inter-substrate conduction material109a, including conductive particles, is provided on this inter-substrate conduction electrode109, and the common electrode21of the opposite substrate20is electrically connected to the element substrate10, through the inter-substrate conduction material109aand the inter-substrate conduction electrode109. For this reason, common potential Vcom, provided from the element substrate10, is applied to the common electrode21. The sealant107is provided along the outer peripheral line of the opposite substrate20, in such a manner as to keep the sealant107in almost the same width. For this reason, the sealant107is in the near rectangular form. However, the sealant107is provided in such a manner as to pass inward to avoid the inter-substrate conduction electrode109in the area overlapping the corner part of the opposite substrate20, and the corner part of the sealant107is in the form of an arc.

In this configuration, the electro-optical device100may make up a transmission-type liquid crystal device, when the pixel electrode9aand the common electrode21are formed using a translucent conducting layer such as an ITO (Indium Tin Oxide) layer and an IZO (Indium Zinc Oxide) layer. In contrast, the electro-optical device100may make up a reflection-type liquid crystal device, when the common electrode21is formed using the translucent conducting layer such as the ITO layer and the IZO layer, and the pixel electrode9ais formed using a reflective conducting layer such as an aluminum layer. In the case where the electro-optical device100is a reflection type, incident light from the opposite substrate20is modulated to display an image while it reflects off the element substrate10and is emitted. In the case where the electro-optical device100is a transmission type, incident light from one of the element substrate10and the opposite substrate20is modulated to display an image while the incident light penetrates the other and is emitted.

The electro-optical device100may serve as a color display device for an electronic device such as a mobile computer, or a portable telephone. In this case, a color filter (not shown) and a protective film are formed on the opposite substrate20. Furthermore, in the electro-optical device100, a phase difference film, a polarizing plate and others are provided in a given direction with respect to the liquid crystal panel100p, separately depending on a kind of a liquid crystal layer50in use, a normal white mode and a normal black mode. In addition, the electro-optical device100may serve as a light valve for RGB in a projection-type display device (a liquid crystal projector), which is described below. In this case, a color filter isn't formed, because each light of the colors, which were separated through a dichroic mirror for RGB color separation, is made to be incident on each of the electro-optical devices100for RGB, as the incident light.

In this embodiment, the electro-optical device100is described, focusing on the case where the electro-optical device100is a transmission-type liquid crystal device that is served as the light valve for RGB, in the projection-type display device to be described below, and incident light from the opposite substrate20penetrates the element substrate10and is emitted. Furthermore, in the embodiment, the electro-optical device100is described, focusing on a case where the electro-optical device100includes a liquid crystal panel100pof VA mode that uses nematic liquid crystal compound with negative dielectric anisotropy, as a liquid crystal layer50.

Specific Configuration of Pixel

FIGS. 3A and 3Bare explanatory views of the pixels of the electro-optical device100to which the aspect of the invention is applied.FIG. 3Ais a top view of the adjacent pixels in the element substrate10.FIG. 3Bis a cross sectional view of the electro-optical device100cut in a position corresponding to line IIIB-IIIB inFIG. 3A. InFIG. 3A, the following areas are indicated by the corresponding lines.

A scan line3ais indicated by a thick solid line. A semiconductor layer1ais indicated by a thin short dotted line. The data line6aand a drain electrode6bare indicated by an alternate long and short dash line. The first electrode layer5aand a relay electrode5bare indicated by a long thin dotted line. The second electrode layer7ais indicated by a chain double-dashed line. The pixel electrode9ais indicated by a thick short dotted line.

As shown inFIG. 3A, a pixel electrode9a, rectangular in shape, is formed on each of the pixels100a, and data lines6aand scan lines3aare formed along an area overlapping an inter-pixel area10finterposed between the adjacent pixel electrodes9a, in the element substrate10. More specifically, the scan line3aextends along an area overlapping a first inter-pixel area10gextending in the first direction (in the X direction), and the data line6aextends along an area overlapping a second inter-pixel area10hextending in the second direction (in the Y direction), on an inter-pixel area10f. Each of the data line6aand the scan line3aextends in the straight line, and the pixel transistor30is formed in an area where the data line6aand the scan line3aintersect. As described referring toFIG. 1, the first electrode layer5a(a capacity electrode layer) is formed on the element substrate10, in such a manner that the first electrode layer5aoverlaps the data line6a.

As shown inFIGS. 3A and 3B, the element substrate10includes a substrate body10wof translucency, such as a quartz substrate and a glass substrate, a pixel electrode9aformed in the direction of the liquid crystal layer50over the substrate body10wof (upward from one side10S of the substrate body10w), pixel transistor30for pixel switching, and an oriented film16, as main components. The opposite substrate20includes a substrate body20wof translucency, such as a quartz substrate and a glass substrate, the common electrode21, formed on a surface of the substrate body20win the direction of a liquid crystal layer50(on the one side opposite to the element substrate10), and an oriented film26, as main elements.

The scan line3ais formed on one side of the substrate body10w, from a conducting layer such as a conductive polysilicon film, a metal silicide film, a metal film, or metal film chemical compound, on the element substrate10. In the embodiment, the scan line3amay include a light shielding conductive film such as tungsten silicide (WSix), and functions as a light shielding film for a pixel transistor30. In the embodiment, the scan line3ais made from tungsten silicide, approximately 200 nm in thickness. An insulating film, such as a silicon oxide film, may be provided between the substrate body10wand the scan line3a.

An insulating film12, such as a silicon oxide film, is formed on the scan line3a, in the upward direction, and the pixel transistor30having the semiconductor layer1ais formed on the surface of the insulating layer12, on the one side10sof the substrate body10w. In the embodiment, the insulating layer12has, for example, a two-layer structure which is composed of a silicon oxide film formed by a low pressure CVD method of using tetraethoxysilane (Si(OC2H5)4), or by a plasma CVD method of using tetraethoxysilane and oxygen gas, and a silicon oxide film (a HTO (High Temperature Oxide) film) formed by a high temperature CVD method.

The pixel transistor30includes the semiconductor layer1aand a gate electrode3c. The semiconductor layer1afaces the long side direction in the extension direction of the scan line3ain an intersection area where the scan line3aand the data line6aintersect. The gate electrode3cextends in the direction perpendicular to the lengthwise direction of the semiconductor layer1a, and overlaps the middle part of the semiconductor layer1ain the lengthwise direction. Furthermore, the pixel transistor30includes a gate insulating layer2of translucency between the semiconductor layer1aand the gate electrode3c. The semiconductor layer1aincludes a channel area1gfacing a gate electrode3cthrough the gate insulating layer2, and includes a source area1band a drain area1cnext to both sides of the channel area1g, respectively. In the embodiment, the pixel transistor30has an LDD structure. Therefore, the source area1band drain area1chave low concentration areas1b1and1c1, with the channel area1gin between, respectively, and have high concentration areas1b2and1c2, next to the low concentration area1b1and1c1, respectively. The concentration area1b1and1c1are positioned between the channel area1gand the high concentration1b2and between the channel area1gand the high concentration1c2.

The semiconductor layer1aincludes, for example, a polycrystalline silicon film. The gate insulating layer2has a two-layer structure. This two-layer structure consists of a first gate insulating layer2a, which is a silicon oxide film formed by thermal oxidation of the semiconductor layer1a, and a second gate insulating layer2b, which is a silicon oxide film formed by, for example, the CVD method. The gate electrode3cis formed from a polysilicon film of conductivity, a metal silicide film, a metal film, or a conductive layer such as a metal film chemical compound. With the semiconductor layer1ain between, the gate electrode3cis electrically connected to the scan line3a, through contact holes12aand12bpassing through the second gate insulating layer2band the insulating layer12. In the embodiment, the gate electrode3chas a two-layer structure, which consists of a conductive polysilicon film, approximately 100 nm in thickness and a tungsten silicide film, approximately 100 nm in thickness.

In the embodiment, light reflecting off the other components after penetrating the electro-optical device100is incident on the semiconductor layer1a, and thus malfunction due to photoelectric current takes place in the pixel transistor30. In the embodiment, the scan line3ais formed like a light shielding film, in order to prevent this. However, the scanning line may be formed on the gate insulating layer2, and one portion of the scanning line may serve as the gate electrode3c. In this case, the scan line3a, as shown inFIGS. 3A and 3B, is formed for the purpose of light shielding only.

An inter-layer insulating film41of translucency, which is made from, for example, a silicon oxide film, is formed on the gate electrode3c, in the upward direction, and a data line6aand a drain electrode6bare formed on an inter-layer insulating film41, from the same kind of insulating film. The inter-layer insulating film41, for example, is made from a silicon oxide film formed by a plasma CVD method of using silane gas (SH4) and nitrous oxide (N2O).

The data line6aand the drain electrode6bare made from a conductive layer, such as a conductive polysilicon film, a metal silicide film, a metal film, or a metal film chemical compound. In the embodiment, the data line6aand the drain electrode6bhave a four-layer structure, which is built by depositing a titanium (Ti) film, 20 nm in thickness, titanium nitride (TiN) film, 50 nm in thickness, aluminum (Al) film, 350 nm in thickness, and TiN film, 150 nm in thickness, in this order. The data line6ais electrically connected to a source area1b(a source drain area to the side of the data line) through a contact hole41apassing through an inter-layer insulating film41and a second gate insulating layer2b. The drain electrode6bis formed in such a manner as to partly overlap the drain area1cof the semiconductor layer1a(a source drain area to the side of the pixel electrode) in an area overlapping the first inter-pixel area10g, and is electrically connected to the drain area1cthrough a contact hole41bpassing through the inter-layer insulating film41and the second gate insulating layer2b.

An inter-layer insulating film42of translucency, which is made from, for example, the silicon oxide film, is formed on the data line6aand the drain electrode6b, in the upward direction. The inter-layer insulating film42, for example, is made from the silicon oxide film formed by, for example, a plasma CVD method of using tetraethoxysilane and oxygen gas.

The first electrode layer5aand the relay electrode5bare formed on the inter-layer insulating film42in the upward direction, from the same kind of insulating film. The first electrode layer5aand the relay electrode5bare made from a conductive polysilicon film, a metal silicide film, a metal film, a metal film chemical compound, or others. In the embodiment, the first electrode layer5aand the relay electrode5bhave a two-layer structure, which consists of an Al film, approximately 350 nm in thickness and a TiN film, approximately 150 nm in thickness. Like the data line6a, the first electrode layer5aextends along an area overlapping the second inter-pixel area10h. The relay electrode5bis formed in such a manner as to partly overlap a drain electrode6bin an area overlapping the first inter-pixel area10g, and is electrically connected to a drain electrode6bthrough a contact hole42apassing through the inter-layer insulating film42.

An insulating film44of translucency (a first insulating film) is formed as an etching stopper layer on the first electrode layer5aand the relay electrode5b, in the upward direction, and an opening44bis formed in an area overlapping the first electrode layer5aon the insulating film44. In the embodiment, the insulating film44is made from, for example, the silicon oxide film formed by, for example, a plasma CVD method of tetraethoxysilane and oxygen gas. At this point, the opening44b, not shown inFIG. 3A, is L-shaped, in such a manner as to have a portion extending along an area overlapping the first inter-pixel area10g, starting from an intersection area where the data line6aand the scan line3aintersect, and a portion extending along an area overlapping the second inter-pixel area10h, starting from an intersection area where the data line6aand the scan line3aintersect.

A dielectric layer40of translucency is formed on the insulating film44, in the upward direction, and the second electrode layer7ais formed on the dielectric layer40, in the upward direction. The second electrode layer7ais made from a conductive polysilicon film, a metal silicide film, a metal film, a metal film chemical compound, or others. In the embodiment, the second electrode layer7ais made from a TiN film, approximately 300 nm in thickness. Silicon compound, such as a silicon oxide film and a silicon nitride film, may serve as the dielectric layer40. In addition, a dielectric layer of high conductivity, such as an aluminum oxide film, a titanium oxide film, a tantanlum oxide film, a niobium oxide film, a hafnium oxide film, a lanthanum oxide film, and a zirconium oxide film, may serve as the dielectric layer40. The second electrode layer7ais L-shaped, in such a manner as to have a portion extending along an area overlapping the first inter-pixel area10g, starting from an intersection area where the data line6aand the scan line3aintersect, and a portion extending along an area overlapping the second inter-pixel area10h, starting from the intersection area where the data line6aand the scan line3aintersect. Therefore, in the region of the second electrode layer7a, a portion extending along the area overlapping the second inter-pixel area10hoverlaps the first electrode layer5a, with the dielectric layer40in between, around the opening44bin the insulating film44. In the embodiment, the first electrode layer5a, the dielectric layer40, and the second electrode layer7amake up the storage capacitance55in an area overlapping the first inter-pixel area10g, in this manner.

Furthermore, in the region of the second electrode layer7a, a portion extending along an area overlapping the first inter-pixel area10gpartly overlaps the relay electrode5b, and is electrically connected to the relay electrode5bthrough a contact hole44apassing through the dielectric layer40and the insulating film44.

An inter-layer insulating film45of translucency is formed on the second electrode layer7a, in the upward direction, and the pixel electrode9a, made from a conductive layer of translucency such as an ITO film approximately 20 nm in thickness, is formed on the inter-layer insulating film45, in the upward direction. The inter-layer insulating film45, for example, is made from a silicon oxide film formed by, for example, a plasma CVD method of using tetraethoxysilane and oxygen gas. The pixel electrode9apartly overlaps the second electrode layer7anear an intersection area where the data line6aand scan line3aintersect, and pixel electrode9aand is electrically connected to the pixel electrode9aand the second electrode layer7a, in a contact portion9t, which is described below.

The oriented film16is formed on the surface of the pixel electrode9a. The oriented film16is made from a polymeric film such as polyimide, or from an oblique deposition film such as a silicon oxide film. In the embodiment, the oriented film16is an inorganic oriented film (a vertical oriented film), made from an oblique deposition film, such as SiOx(x<2), SiO2, TiO2, MgO, Al2O3, In2O3, Sb2O3, Ta2O5, or others.

In the opposite substrate20, the common electrode21, made from a conductive film of translucency such as ITO film, is, in the direction of the liquid crystal layer50(in the direction of facing the element substrate10), formed on the surface of a substrate body20wof translucency, such as a quartz substrate and a glass substrate, and the oriented film26is formed in such a manner as to cover this common electrode21. Like the oriented film16, the oriented film26is made from a polymeric film such as polyimide, or from an oblique deposition film such as a silicon oxide film. In the embodiment, the oriented film26is an inorganic oriented film (a vertical oriented film) made from the oblique deposition film, such as SiOx(x<2), SiO2, TiO2, MgO, Al2O3, In2O3, Sb2O3, Ta2O5, or others. These oriented films16and26cause the vertical orientation of nematic liquid crystal compound with negative dielectric anisotropy in the liquid crystal layer50, so that the liquid crystal panel100poperates in the VA mode of normal black.

A complementary transistor circuit, having a re-channel type transistor for driving and a p-channel type transistor for driving, is included in the data line drive circuit101and the scan line drive circuit104, above described referring toFIGS. 1 to 2B. At this point, the transistor for driving may be formed by using process steps of manufacturing the pixel transistor30. For this reason, an area where the data line drive circuit101and the scan line drive circuit104are formed, has the almost same configuration as the cross sectional area shown inFIG. 3B, in the element substrate10.

Peripheral Configuration of Pixel Electrode9a

In the embodiment, a pillar-shaped protrusion440, protruding toward a pixel electrode9a, is first formed in a position overlapping the pixel electrode9ain the insulating film44(the first insulating film), in forming a contact portion9tconnecting electrically between the pixel electrode9aand the second electrode layer7a, in the electro-optical device100. Furthermore, the second electrode layer7a(conductive layer) is formed in an area overlapping the pillar-shaped protrusion440in the second electrode layer7a. A portion overlapping the pillar-shaped protrusion440when viewed from above becomes a conduction section7tconnecting electrically to the pixel electrode9a. The inter-layer insulating film45(the second insulating film) is formed on the second electrode layer7a, and a surface7sof a conduction section7tis exposed on a surface450of the inter-layer insulating film45. Therefore, a pixel electrode9aformed on the surface450of the inter-layer insulating film45gets in contact with the surface7sof the conduction section7t, and thus is electrically connected to the second electrode layer7a.

At this point, the surface450of the inter-layer insulating film45becomes plane, and thus the surface450of the inter-layer insulating film45and the surface7sof the conduction section7tin succession makes up one plane. For this reason, the pixel electrode9ais formed on a plane surface, and thus the surface of the pixel electrode9ais plane. Therefore, the oriented film16is formed on a plane surface, next to the surface of the pixel electrode9a.

In the embodiment, the pillar-shaped protrusion440is formed at a position overlapping the first electrode layer5aand the data line6a, when viewed from above. For this reason, the pillar-shaped protrusion440is positioned over a film-thick portion of the first electrode layer5aand the film-thick portion of the data line6a.

In the embodiment, the first electrode layer5a, to which common potential Vcom is applied, and the second electrode layer7a, to which the potential Vsig is applied, are formed in an area overlapping an area (the second inter-pixel area10h) between the pixel electrodes9aadjacent in the first direction (in the X direction), but the second electrode layer7ais positioned over the first electrode layer5a(to the side of the pixel electrode9a), in the upward direction. At this point, the potential Vsig applied to the second electrode layer7ais the same as that applied to the pixel electrode9a. The scan line3a, to which the scan signal is applied, and the second electrode layer7a, to which the potential Vsig is applied, are formed in an area overlapping an area (the first inter-pixel area10g) between the pixel electrodes9aadjacent in the second direction (in the Y direction), but the second electrode layer7ais positioned over the scan line3a(to the side of the pixel electrode9a) in the upward direction. At this point, the potential Vsig applied to the second electrode layer7ais the same as that applied to the pixel electrode9a.

Manufacturing Method of the Electro-Optical Device100

FIGS. 4A to 5Eare explanatory views of showing the essential steps of a manufacturing process of the electro-optical device100to which the aspect of the invention is applied. The steps are actually performed on a large-sized substrate which is to be divided into a plurality of element substrates10in the subsequent step, but is below described in terms of the element substrate10regardless of the size of the substrate. Furthermore, the proceeding steps of forming the first electrode layer5aare well known in the art and therefore are not described below.

In the manufacturing process of the electro-optical device100according to the embodiment, in the step of forming the element substrate10, the insulating film44(the first insulating film) is formed from a silicon oxide film, approximately 600 nm in thickness by, for example, a plasma CVD method of tetraethoxysilane and oxygen gas, in the step of forming the first insulating film, after the first electrode layer5aand the relay electrode5bare formed by a well-known method as shown inFIG. 4A. The first electrode layer5ahas a two-layer structure, which consists of an Al film, approximately 350 nm in thickness and a Tin film, approximately 150 nm in thickness.

Next, a mask44ris formed in a position overlapping an area where the pixel electrode9aneeds to be formed, and, under this condition, the surface of the insulating film44is etched, in the insulating film44in a step of forming the pillar-shaped protrusion as shown inFIG. 4B. As a result, the pillar-shaped protrusion440, protruding upward, is formed on the insulating film44. This etching may be performed by a RIE (reactive ion etching) method of using fluorine-series gas such as CF4(tetrafluoromethane) and CHF3(methane trifluoride), and therefore is high in etching anisotropy. In addition, the etching ensures easy control of an amount of etching. Therefore, the pillar-shaped protrusion440may be formed on the insulating film44, in an easy manner and without any failure.

Next, in a step of forming an opening, as shown inFIG. 4C, a mask44s, for making an opening in an area where the opening44bneeds to be formed, is formed on the surface of the insulating film44, and, under this condition, the opening44bis formed by etching the insulating film44.

Next, as shown inFIG. 4D, a dielectric layer40is formed on the insulating film44, in the upward direction, in a step of forming a dielectric layer.

Next, in a step of forming a contact hole, as shown inFIG. 4E, a mask44t, for making an opening in an area where a contact hole44aneeds to be formed, is formed on the surface of the dielectric layer40, and, under this condition, the contact hole44ais formed in a position overlapping the relay electrode5bby etching the dielectric layer40and the insulating film44.

Next, as shown inFIG. 5A, a mask7ris formed in an area where the second electrode layer7aneeds to be formed, and, under this condition, the second electrode layer7ais formed by etching the dielectric layer40and the conductive layer7, after a conductive layer7was formed on the surface of the dielectric layer40in a step of forming a conductive layer, as shown inFIG. 4F. At this point, a portion overlapping the highest surface of the pillar-shaped protrusion440in the second electrode layer7abecomes a conduction section7t, when this step is performed, the insulating film44exists as an etching stopper layer, in a position overlapping the highest portion of the second electrode layer7a. For this reason, short circuit between the first electrode layer5aand the second electrode layer7amay be prevented by the insulating film44, although the dielectric layer40is thin. In the embodiment, the second electrode layer7a, is made from, for example, a TiN film, approximately 300 nm in thickness.

Next, in a step of forming a second insulating film, as shown inFIG. 5B, the inter-layer insulating film45(the second insulating film) is formed from a silicon oxide film, approximately 2000 nm in thickness, by a plasma CVD method of using tetraethoxysilane and oxygen gas.

Next, in a step of exposing a conduction section, as shown inFIG. 5C, the surface7sof the conduction section7tof the second electrode layer7ais exposed by removing the inter-layer insulating film45from the surface450. In this step of exposing the conduction section, for example, a surface of the inter-layer insulating film45is polished. In this polishing step, chemical mechanical polishing may be performed, and thus, a smooth polished surface may be accomplished at high speed by action of chemical composition contained polishing liquid and by the relative movement between a polishing agent and the element substrate10. More specifically, polishing apparatus performs polishing by producing the relative movement between a surface plate to which a polishing cloth (a pad) is attached, and a holder holding the element substrate10. The polishing cloth may be made from non-woven fabric, foamed polyurethane, porous fluorocarbon resin, and other materials. At this point, for example, a polishing agent is provided between the polishing cloth and the element substrate10. The polishing agent includes a cerium oxide particle with an average diameter of 0.01 μm to 20 μm, acrylic acid ester derivative as a dispersing agent, and water. As a result, the surface450of the inter-layer insulating film45becomes plane, and is at the same level as the surface7sof the conduction section7t.

Furthermore, a so-called etch back method may be alternatively used in removing the inter-layer insulating film45from the surface450in the downward direction to expose the surface7sof the conduction section7tof the second electrode layer7a. In this etch back method, dry etching is performed on a resin layer and the inter-layer insulating film45at the same speed, until the surface7sof the conduction section7tis exposed, after forming the resin layer on the surface of the inter-layer insulating film45.

Next, in a step of forming a pixel electrode, a mask9r, as shown inFIG. 5E, is formed in an area where a pixel electrode9aneeds to be formed, and, under this condition, the pixel electrode9ais formed by etching a conductive film9for the pixel electrode, after forming the conductive film9for the pixel electrode, such as an ITO film, approximately 20 nm in thickness, on the surface of the inter-layer insulating film45, by using, for example, the sputtering method, as shown inFIG. 5D. As a result, the pixel electrode9acomes in contact with the surface7sof the conduction section7tof the second electrode layer7a, and thus is electrically connected to the second electrode layer7a.

Thereafter, an oriented film16is formed as shown inFIGS. 3A and 3B. Subsequent steps are performed by using well-known methods and therefore are not described.

Main Effects of the Embodiment

As is above described, in the electro-optical device100and the manufacturing method of the electro-optical device100according to the embodiment, the pillar-shaped protrusion440, protruding at the position overlapping the pixel electrode9atoward the pixel electrode9a, is formed on the insulating film44(the first insulating film) provided below the pixel electrode9a(between the pixel electrode9aand the substrate body10w), in the downward direction, and thus the conduction section7tof the second electrode layer7a(the conductive layer) overlaps the highest surface of this pillar-shaped protrusion440. Furthermore, the inter-layer insulating film45(the second insulating film) is provided between the second electrode layer7aand the pixel electrode9a, but the conduction section7tis exposed on the surface450of the inter-layer insulating film45. For this reason, the pixel electrode9ais electrically connected to the conduction section7t, when the pixel electrode9ais deposited on the inter-layer insulating film45. For this reason, the contact portion is smaller in horizontal size, the pixel electrode does9adoes not have a large depression and elevation on the surface, compared to the structure that connects the pixel electrode and the conductive layer by using the contact hole formed in the insulating film. Furthermore, conduction of the pixel electrode9amay be done by using the film formed in the electro-optical device100for other purposes, such as the second electrode layer7a, the insulating film (the insulating film44and the inter-layer insulating film45), and others. That is, conduction of the pixel electrode9amay be done by using the insulating film44that functions as the etching stopper layer, and the second electrode layer7amaking up the storage capacitance55. Therefore, in the embodiment, there is no need to deposit thickly a special thick metal for the plug.

Furthermore, in the embodiment, the pixel electrode9amay be formed on the plane surface, since the surface7sof the conduction section7tand the surface450of the inter-layer insulating film45, which adjoin each other in succession, are at the same level. Therefore, the surface of the pixel electrode9ais made to be plane. Therefore, the oriented film16may be formed on the plane surface of the pixel electrode9a, and thus the oriented film16may be formed in a suitable manner. Furthermore, the pillar-shaped protrusion440is formed at the position overlapping the first electrode layer5aand the data line6a, when viewed from above. For this reason, since the pillar-shaped protrusion440is positioned over the film-thick portion of the first electrode layer5aand the film-thick portion of the data line6a, the conduction section7tis easy to expose on the surface of the inter-layer insulating film45. This provides a condition suitable for the formation of the contact portion9tof the pixel electrode9a.

Other Effects of the Embodiment

FIGS. 6A and 6Bare explanatory views showing the effects of the electro-optical device100to which the aspect of the invention is applied.FIG. 6Ais a schematic configuration of the pixel electrodes in the electro-optical device100.FIG. 6Bis a schematic configuration of the pixel electrodes in the comparative example.

As shown inFIGS. 3A,3B, in the electro-optical device100according to the embodiment, the second electrode layer7a(the conductive layer) and the first electrode layer5a(the capacity electrode layer) are provided in an area overlapping the area (the second inter-pixel area10f) between the pixel electrodes9aadjacent in the X direction. However, as shown inFIG. 6A, in this embodiment, the second electrode layer7ais positioned over the first electrode layer5ain the upward direction (near the pixel electrode9a). For this reason, the orientation of the liquid crystal layer50is not disturbed by electric potential occurring between the pixel electrode9aand the first electrode layer5a.

More specifically, as shown inFIGS. 6A and 6B, in the electro-optical device100, the orientation of liquid crystal molecules of the liquid crystal layer50is controlled by a longitudinal electric field (indicated by an arrow V1) between the pixel electrode9ain the element substrate10and the common electrode21to which the common potential Vcom is applied in the opposite substrate20, and optical modulation is performed on each pixel. At this point, the common potential Vcom is applied to the first electrode layer5aand the potential Vsig is applied to the second electrode layer7a. The potential Vsig applied to the second electrode layer7ais the same as that applied to the pixel electrode9a. For this reason, as is shown in the comparative example ofFIG. 6B, when the first electrode layer5ais positioned over second electrode layer7ain the upward direction (near the pixel electrode9a), an unnecessary electric field (indicated by an arrow V2) occurs between the highest portion of the pixel electrode9aand the first electrode layer5a, and thus disturbance of potential distribution occurs near the highest portion of the pixel electrode9a.

In contrast, in the embodiment, the second electrode layer7ais positioned over the first electrode layer5ain the upward direction (near the pixel electrode9a). Since the unnecessary electric field, indicated by the arrow V2, does not occur for this reason, the disturbance of the potential distribution does not occur near the highest portion of the pixel electrode9a, and thus the distribution of liquid crystal molecules may be controlled even near the highest portion of the pixel electrode9a, in a suitable manner. Even though an electric field occurs in an area between the pixel electrode9aand the second electrode layer7a(the area is positioned near the pixel electrode9a), this electric field does not cause critical effects, because potential difference is small, compared to the potential (common potential Vcom) applied to the first electrode layer5a.

Other Embodiments

In the embodiment, the example is above described in which the aspect of the invention is applied to the transmission-type electro-optical device100, but the aspect of the invention may be applied to the reflection-type electro-optical device100.

Furthermore, the example is described in which the aspect of the invention is applied to the electro-optical device100, but the aspect of the invention may be applied to other electro-optical devices, such as an organic electroluminescence device.

Example of Equipping Electronic Device with Electro-Optical Device

Configuration Example of Projection-Type Display Device and Optical Unit

FIGS. 7A and 7Bare schematic configurations of a projection-type display device to which the aspect of the invention is applied and an optical unit.FIG. 7Ais a schematic configuration of the projection-type display device using the transmission-type electro-optical device.FIG. 7Bis a schematic configuration of the projection-type display device using the reflection-type electro-optical device.

A projection-type display device110, as shown inFIG. 7A, is an example of using a transmission-type liquid crystal panel as a liquid crystal panel. In contrast, the projection-type display device1000, as shown inFIG. 7B, is an example of using the reflection-type liquid crystal panel as a liquid crystal panel. However, as is below described, the projection-type display device110includes a light source unit130, a plurality of electro-optical devices100receiving light of different wavelength regions from the light source unit130, a cross dichroic prism119(an optical system of photosynthesis) synthesizing and emitting the light from the plurality of the electro-optical devices100, and a projection optical system118projecting the light synthesized by the cross dichroic prism119. Likewise, a projection-type display device1000includes a light source unit1021, a plurality of electro-optical devices100receiving light of different wavelength regions from the light source unit1021, a cross dichroic prism1027(the optical system of photosynthesis) synthesizing and emitting the light from the plurality of the electro-optical devices100, and a projection optical system1029projecting the light synthesized by the cross dichroic prism1027. Furthermore, an optical unit200, including the electro-optical device100and the cross dichroic prism119(the optical system of photosynthesis), is used in the projection-type display device110. Likewise, an optical200, including the electro-optical device100and the cross dichroic prism1027(the optical system of photosynthesis), is used in the projection-type display device1000.

First Example of Projection-type Display Device

The projection-type display device110, as shown inFIG. 7A, projects light onto a screen111prepared by a viewer, and the viewer sees the light reflected by the screen111. The projection-type display device110is a so-called screen-reflected type. The projection-type display device110includes a light source unit130including a light source112, dichroic mirrors113and114, liquid crystal light valves115,116, and117, a projection optical system118, a cross dichroic prism119(the optical system of photosynthesis), and a relay system120.

The light source112includes an extra-high pressure mercury lamp supplying light including red light R, green light G, and blue light B. The dichroic mirror113has a configuration that allows red light R from the light source112to penetrate, but reflects green light G and blue light B from the light source112. Furthermore, the dichroic mirror114has a configuration that allows blue light B, reflected by the dichroic mirror113, to penetrate, but reflects green light G, reflected by the dichroic mirror113. In this way, the dichroic mirrors113and114make up a color separation optical system that separates light emitted from the light source112into red light R, green light G, and blue light B.

At this point, an integrator121and a polarization conversion element122are arranged in this order from the light source112between the dichroic mirror113and the light source112. The integrator121has a configuration that makes uniform the illumination distribution of light emitted from the light source112. Furthermore, the polarization conversion element122has a configuration that converts light emitted from the light source112into polarized light having a specific vibration direction, such as s polarized light.

The liquid crystal light valve115is a transmission-type electro-optical device that modulates red light R that penetrates the dichroic mirror113, but reflects off a reflecting mirror123, in response to an image signal. The liquid crystal light valve115includes a λ/2 phase difference plate115a, a first polarizing plate115b, the electro-optical device100(a liquid crystal panel100R for red), and a second polarization115d. At this point, the red light R that is incident on the liquid crystal light valve115does not experience any change in polarized light and therefore maintains s polarized light even though the red light R penetrated the dichroic mirror113.

The λ/2 phase difference plate115ais an optical element that converts s polarized light, that is incident on the liquid crystal light valve115, into p polarized light. Furthermore, the first polarizing plate115bis a polarizing plate that blocks s polarized light and allows p polarized light to penetrate. The electro-optical device100(a liquid crystal panel100R for red) has a configuration that converts p polarized light into s polarized light (circularly polarized light or elliptically polarized light in the case of a half tone), by modulation that is in response to the image signal. In addition, the second polarizing plate115dis a polarizing plate that blocks p polarized light and allows s polarized light to penetrate. Therefore, the liquid crystal light valve115has a configuration that modulates red light R in response to the image signal, and emits the modulated red light R toward the cross dichroic prism119.

The λ/2 phase difference plate115aand the first polarizing plate115bis arranged in such a manner as to be in contact with a glass plate115eof translucency that does not convert polarized light, and therefore the λ/2 phase difference plate115aand the first polarizing plate115bmay be prevented from warping due to generated heat.

The liquid crystal light valve116is a transmission-type electro-optical device that modulates green light G that reflected off the dichroic mirror114after reflecting off the dichroic mirror113, in response to the image signal. The liquid crystal light valve116, like the liquid crystal light valve115, includes a first polarizing plate116b, the electro-optical device100(a liquid crystal panel100G for green), and a second polarizing plate116d. The green light G that is incident on the liquid crystal light valve116, is s polarized light that reflected off the dichroic mirrors113and114. The first polarizing plate116bis a polarizing plate that blocks p polarized light and allows s polarized light to penetrate. Furthermore, the electro-optical device100(the liquid crystal panel100G for green) has a configuration that converts s polarized light into p polarized light (circularly polarized light, or elliptically polarized light in a case of a half tune) by modulation that is in response to the image signal. The second polarizing plate116dis a polarizing plate that blocks s polarized light and allows p polarized light to penetrate. Therefore, the liquid crystal light valve116has a configuration that modulates green light G in response to the image signal, and emits the modulated green light G toward the cross dichroic prism119.

The liquid crystal light valve117is a transmission-type electro-optical device that modulates blue light B that reflected off the dichroic mirror113, penetrated the dichroic mirror114, and then passed through the relay system120, in response to the image signal. The liquid light valve117, like the liquid crystal light valves115and116, includes a λ/2 phase difference plate117a, a first polarizing plate117b, the electro-optical device100(a liquid crystal panel100B for blue), and a second polarizing plate117d. At this point, the blue light B that is incident on the liquid light valve117becomes s polarized light, because the blue light B that reflected off the dichroic mirror113and penetrated the dichroic mirror114reflects off two reflecting mirrors125aand125b, which are described below, of the relay system120.

The λ/2 phase difference plate117ais an optical element that converts s polarized light that was incident on the liquid light valve117, into p polarized light. Furthermore, the first polarizing plate117bis a polarizing plate that blocks s polarized light and allows p polarized light to penetrate. The electro-optical device100(the liquid crystal panel100B for blue) has a configuration that converts p polarized light into s polarized light (circularly polarized light, or elliptically polarized light in a case of a half tune) by modulating p polarized light in response to the image signal. In addition, the second polarizing plate117dis a polarizing plate that blocks p polarized light and allows s polarized light to penetrate. Therefore, the liquid crystal light valve117has a configuration that modulates blue light B in response to the image signal, and emits the modulated blue light B toward the cross dichroic prism119. The λ/2 phase difference plate117aand the first polarizing plate117bare arranged in such a manner as to be in contact with the glass plate117e.

The relay system120includes relay lenses124aand124b, and reflecting mirrors125aand125b. The relay lenses124aand124bare provided to prevent optical loss that is due to a long optical path of blue light B. At this point, the relay lens124ais arranged between the dichroic mirror114and the reflecting mirror125a. Furthermore, the relay lens124bis arranged between the reflecting mirrors125aand125b. The reflecting mirror125ais arranged in such a manner as to reflect blue light B that penetrated the dichroic mirror114and was emitted from the relay lens124a, toward the relay lens124b. Furthermore, the reflecting mirror125bis arranged in such a manner as to reflect blue light B that was emitted from the relay lens124b, toward the liquid light valve117.

The cross dichroic prism119is an optical system of color synthesis, in which the two dichroic films119aand119bcross at a right angle in an X shape. The dichroic film119areflects blue light B and allows green light G to penetrate. The dichroic film119breflects red light R and allows green light G to penetrate. Therefore, the cross dichroic prism119has a configuration that synthesizes red light R, green light G, and blue light B modulated in the liquid crystal light valves115,116,117, respectively, and emits the synthesized red light R, green light G, and blue light B toward the projection optical system118.

Light which is incident on the cross dichroic prism119from the liquid crystal light valves115and117is s polarized light, and light is p polarized light which is incident on the cross dichroic prism119from the liquid crystal light valve116is p polarized light. Light that is incident on the cross dichroic prism119is made to be different kinds of polarized light in this way, and thus light emitted from the liquid crystal light valves115,116, and117may be synthesized in the cross dichroic prism119. Generally, each of the dichroic films119aand119bhave excellent reflection transistor characteristic of s polarized light. For this reason, red light R and blue light B that is reflected by the dichroic films119aand119bis determined as s polarized light, and green light G that penetrates the dichroic films119aand119bis determined as p polarized light. The projection optical system118has a configuration that includes a projection lens (not shown) and projects light synthesized by the cross dichroic prism119onto the screen111.

Second Example of Projection-Type Display Device

The projection-type display device1000, as shown inFIG. 7B, includes a light source unit1021generating light source light, a color separation light guide optical system1023separating the light source light emitted from the light source unit1021into 3 color light of red light R, green light G, and blue light B, and a light modulating unit1025that is illuminated by each light source light emitted from the color separation light guide optical system1023. Furthermore, the projection-type display device1000includes a cross dichroic prism1027(the optical system of photosynthesis) synthesizing image light emitted from the light modulating unit1025, and a projection optical system1029projecting the image light passing through the cross dichroic prism1027onto a screen (not shown).

In this projection-type display device1000, the light source unit1021includes a light source1021a, a pair of fly eye optical systems1021dand1021e, a polarized light conversion member1021gand a superimposing lens1021i. In the embodiment, the light source unit1021includes a reflector1021fwith paraboloid surface and emits parallel light. Each of the fly eye optical systems1021dand1021eis made up of a plurality of element lens arranged in the matrix on the surface intersecting a system optical axis. Light-source light is separated by the plurality of the element lens, and then is individually concentrated and radiated. The polarized light conversion member1021gconverts the light-source light emitted from the fly eye optical system1021einto a p polarized light component only, for example, in parallel with the drawing, and supply the p polarized light component to the optical system, down the optical path. The superimposing lens1021ienables each of the electro-optical devices100, provided in the light modulating unit1025, to perform superimposed lighting in a uniform manner, by converging properly the light-source light, as a whole, that passed through the polarized light conversion member1021g.

The color separation light guide optical system1023, includes a cross dichroic mirror1023a, a dichroic mirror1023b, and reflection mirrors1023jand1023k. In the color separation light guide optical system1023, almost white light-source light from the light source unit1021is incident on the cross dichroic mirror1023a. The red light R, reflected by the first dichroic mirror1031a, as one element making up the cross dichroic mirror1023a, reflects off the reflection mirror1023j, penetrates the dichroic mirror1023b. Then, the red light R, polarized light as it is, is incident on the electro-optical device100(a liquid crystal panel100R for red), through a polarizing plate1037r, which is opposite to incident light, a wire grid polarizing plate1032r, which allows p polarized light to penetrate, but reflects s polarized light, and an optical compensation plate1039r.

Furthermore, the green light G, reflected by the first dichroic mirror1031a, reflects off the reflection mirror1023j, and then reflects off the dichroic mirror1023bas well. Then, the green light G, remaining as p polarized light, is incident on the electro-optical device100(a liquid crystal panel100G for green), through a polarized plate1037g, which is opposite to incident light, a wire grid polarizing plate1032g, which allows p polarized light to penetrate, but reflects s polarized light, and an optical compensation plate1039g.

In contrast, the blue light B, reflected by the second dichroic mirror1031b, as the other element making up the cross dichroic mirror1023a, reflects off the reflection mirror1023k. Then, the blue light B is incident on the electro-optical device100(the liquid crystal panel100B for blue), through a polarizing plate1037b, which is opposite to incident light, a wire grid polarizing plate1032b, which allows p polarized light to penetrate, but reflects s polarized light, and an optical compensation plate1039b. The optical compensation plates1039r,1039g, and1039benhance the characteristics of the liquid crystal layer in a compensating manner, by controlling the incident light that is incident on the electro-optical device100and the polarized state of emitted light, in an optical manner.

In the projection-type display device1000with this configuration, each of light of 3 colors, incident after passing through the optical compensation plates1039r,1039g, and1039b, is modulated in the corresponding electro-optical device100. At this point, among modulated light emitted from the electro-optical device100, component light of s polarized light reflects off the wire grid polarizing plates1032r,1032g, and1032b, and is incident on the cross dichroic prism1027, through emitting-side polarizing plates1038r,1038g, and1038b. A first dielectric multi-layered film1027aand a second dielectric multi-layered film1027b, which intersect in an X shape, are formed in an X shape on the cross dichroic prism1027. The first dielectric multi-layered film1027aon one side reflects red light R, and the second dielectric multi-layered film1027bon the other side reflects blue light B. Therefore, light of 3 colors is synthesized in the cross dichroic prism1027, and is emitted to the projection optical system1029. Then, the projection optical system1029projects image light of color synthesized in the cross dichroic prism1027on a given scale onto the screen (not shown).

Other Projection-Type Display Devices

The projection-type display device may use an LED light source emitting each light of color as the light source unit, and have a configuration that provides light of color emitted from this LED light source for a separate liquid crystal device.

Other Electronic Devices

The electro-optical device100to which the aspect of the invention is applied, may serve as a direct-view display device for an electronic device, such as a portable telephone, a PDA (Personal Digital Assistants), a digital camera, a liquid crystal television, a car navigation device, a television telephone, a POS terminal, a device equipped with a touch panel, and others.

The entire disclosure of Japanese Patent Application No. 2011-159619, filed Jul. 21, 2011 is expressly incorporated by reference herein.