Patent ID: 12189247

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the accompanying drawings, a description will hereinafter be made in detail about a first embodiment and a second embodiment of the present invention.

Before describing the first and second embodiments of the present invention, a description will first be made about the configurations of a general liquid crystal display device having a brightness control panel with reference toFIGS.1to4.

FIG.1is an exploded perspective view of the general liquid crystal display device having a brightness control panel. InFIG.1, a first liquid crystal display panel10(hereinafter referred to as “the display panel10”) and a second liquid crystal display panel20(hereinafter referred to as “the brightness control panel20”) are used overlapping each other. A backlight1000is arranged behind the brightness control panel20. This technology may also be referred to as “local dimming.” Described specifically, areas to be dimmed in an image is irradiated with no light. This can realize very high contrast images.

Liquid crystal panels of the same configuration may be used as the display panel10and the brightness control panel20. However, the specification of the display panel and that of the brightness control panel20are made different in parts to improve the brightness and quality of images to be displayed on a screen as the whole display. For example, to improve the brightness of the screen in its entirety, no color filter is used in the brightness control panel20. Further, to prevent interference such as the moire effect between the display panel10and the brightness control panel20, a measure may also be taken, such as making the configuration of wirings different between the display panel10and the brightness control panel20.

FIG.2is a II-II cross-sectional view ofFIG.1, in which the configurations ofFIG.1have been assembled. InFIG.2, the display panel10arranged on an upper side is configured with a first TFT substrate100, on which wirings and TFTs are formed, and a first counter substrate200, a first liquid crystal layer300is held between the first TFT substrate100and the first counter substrate200, and light from the backlight1000is controlled pixel by pixel.

The first TFT substrate100and the first counter substrate200are adhered together along peripheries thereof with a first sealing layer110. The first sealing layer110is formed with as small a width as possible to an extent that can maintain the reliability of the adhesion. As it is only polarized light that a liquid crystal can control, a lower polarizer50(hereinafter referred to as “the first polarizer50”) is arranged on a lower side of the display panel10, and an upper polarizer60(hereinafter referred to as “the second polarizer60”) is arranged on an upper side of the display panel10.

The first TFT substrate100is formed to be greater than the first counter substrate200, and on a portion of the first TFT substrate100where the first TFT substrate100does not overlap the first counter substrate200, a terminal area is formed. On the terminal area, a first IC driver180, which is for driving the display panel10, and the like are arranged. On a portion of the first counter substrate200where the first counter substrate200overlaps the first TFT substrate100, on the other hand, a display area is formed.

InFIG.2, color filters201are formed on the first counter substrate200to form color images. Rs represent red color filters, Gs denote green color filters, and Bs stand for blue color filters. First light-shielding layers202are formed between the respective color filters and on a frame area around the display area, although the first light shielding layers202between the respective color filters are now shown inFIG.2.

The first light shielding layers202have a role in improving the contrast of images at the display area. As many wirings such as scanline leads and a scanline driver circuit concentrate at the peripheral frame area, shielding of light is needed to prevent reflection or the like of light from these wirings. As a light shielding film for the frame area, the first light shielding layer202is hence formed. The first light shielding layer202at the frame area, that is, the frame area is formed with a width greater than that of the first spieling layer110because the first light shielding layer202needs light shielding with respect to the many peripheral wirings.

InFIG.2, the brightness control panel20is arranged on a lower side of the display panel10. The brightness control panel20has fundamentally the same structure as the display panel10except for the pixel structure at a display area. Described specifically, a second TFT substrate400, on which wirings, TFTs, and the like are formed, and a second counter substrate500opposes to each other, and a second liquid crystal layer310exists between the second TFT substrate400and the second counter substrate500. The second TFT substrate400and the second counter substrate500are adhered together with a second sealing layer120. Similar to the first sealing layer110on the side of the display panel10, the second sealing layer120has a small width. On a lower side of the second TFT substrate400, a lower polarizer30(hereinafter referred to as “the third polarizer30”) is arranged.

The second TFT substrate400is formed to be greater than the second counter substrate500, and on a portion of the second TFT substrate400where the second TFT substrate400is exposed from the second counter substrate500, a terminal area is formed. At the terminal area, a second driver IC182and the like, which are for driving the display panel, are arranged. On a portion of the second counter substrate500where the second counter substrate500overlaps the second TFT substrate400, on the other hand, the display area is formed.

No color filters are formed on the second counter substrate500of the brightness control panel20. This is to avoid a reduction in the light transmittance of the brightness control panel20. However, second light shielding layers204are also formed on the second counter substrate500of the brightness control panel20as in the first counter substrate200of the display panel10, because, similar to the display panel10, the brightness control panel20also needs to shield light from the wiring area around the display area. In the brightness control panel20, the second light shielding layer204at the peripheral area, in other words, the frame area also has a width greater than the second sealing layer120.

At the display area of the brightness control panel on the other hand, brightness signal lines are formed in place of video signal lines at the display area of the display panel10, and the second light shielding layers204are formed in registration with the brightness signal lines. This is to prevent reflection of light from the brightness signal lines. As the brightness signal lines are formed at a pitch greater than the video signal lines at the display area of the display panel10, the second light shielding layers204at the display area of the brightness control panel20are also formed at a pitch greater than the first light shielding layers202in the display panel10.

InFIG.2, the display panel10and the brightness control panel20are adhered together with an adhesive, for example, an optical clear adhesive (OCA). Described specifically, the first polarizer50of the display panel and an upper polarizer40(hereinafter referred to as “the fourth polarizer40”) of the brightness control panel are adhered together with an adhesive layer70. OCA that forms the adhesive layer70(which may hereinafter be referred to as “the OCA70”) is an acrylic resin, a silicone-based resin, or the like, and therefore is prone to absorb moisture.

InFIG.2, the backlight1000is arranged on a back surface of the brightness control panel20. LED arrays are used in the backlight1000. LEDs can provide high brightness, but on the other hand, give off a great deal of heat. This heat passes through the brightness control panel20, and reaches the two polarizers40and50, and the OCA70between the brightness control panel20and the display panel10. The polarizing layer in each polarizer is merely held with between the protective layers of cellulose triacetate (TAC) that is prone to absorb moisture, and therefore is exposed to moisture and heat. Accordingly, the deterioration of polyvinyl alcohol (PVA) that makes up each polarizing layer proceeds.

FIG.3is a III-III cross-sectional view ofFIG.1.FIG.3is basically the same asFIG.2except that no terminal areas exist. It is to be noted that the pixel construction of the color filters formed on the first counter substrate200of the display panel10is not exactly the same as that in the II-II cross-section and III-III cross-section, but is drawn as the same structure inFIGS.2and3to facilitate its understanding becauseFIGS.2and3are schematic views. This equally applies to the construction of pixels defined and isolated by the first light shielding layers202in the display panel10. Other configurations are similar to those described above with reference toFIG.2, and the description is omitted accordingly.

As shown inFIGS.2and3, the display panel10and the brightness control panel20are adhered together with the OCA70. Described specifically, the fourth polarizer40bonded to the brightness control panel20and the first polarizer50bonded to the display panel10are adhered together with the OCA70. The polarizers40and50are formed with resins, and the OCA70itself is a resin, so that polarizers40and50, and OCA70are prone to absorb moisture.

Accordingly, the plural layers that are prone to absorb moisture overlap near the OCA70. If moisture penetrates from side surfaces of the polarizers40and50, and OCA70as indicated by an open thick arrow M as shown inFIGS.2and3, the moisture tends to stay in the polarizers40and50, and the like, and the deterioration of the polarizers40and50thus proceeds in the presence of this moisture.

FIG.4is a cross-sectional view of the fourth polarizer40that exemplifies the structure of a polarizer. The fourth polarizer40has a configuration that a polarizing layer41having polarizing effects is held between protective layers42, and a self-adhesive layer43is formed on one of the protective layers42, specifically, the lower protective layer42as seen inFIG.4to bond the lower protective layer42with the second counter substrate500of the brightness control panel20. The remaining polarizers, that is, the third, first, and second polarizers30,50, and60have the same configuration.

The polarizing layer41is formed using PVA as a principal component and impregnating it, for example, with an iodine (I) compound. The polarizing layer41has a thickness t1of, for example, 20 μm. The protective layers42are formed with TAC (which may hereinafter be referred to as “the TACs42”), and have a thickness t2of, for example, 40 μm. The TACs42are hydrophobic, and therefore is prone to absorb moisture. When moisture is absorbed, the TACs42expand. To protect the polarizing layer41from ultraviolet rays, on the other hand, the TACs42are required to absorb ultraviolet rays. It is therefore necessary for the TACs42to have a certain amount of thickness. The self-adhesive layer43is required to have a thickness to retain a sufficient bonding force with the second counter substrate500, so that its thickness t3is, for example, 25 μm. The thickness of the fourth polarizer40alone is therefore approximately 125 μm.

On the other hand, the thickness of the OCA70is, for example, 150 μm. Accordingly, the total thickness of the OCA70and the two polarizers40and50is approximately 400 μm, so that, as indicated by the open thick arrow M inFIGS.2and3, moisture is prone to penetrate from their side surfaces. A part that includes the polarizers40and50, and the OCA70may hereinafter be referred to as “the adhered part.” This adhered part is covered at an upper surface and lower surface thereof with the first TFT substrate100and the second counter substrate500, both of which are made from glass. The penetrated moisture therefore stays in the adhered part.

This means that the polarizing layers41of the polarizers40and50are always exposed to moisture. PVA that makes up the polarizing layers41is hydrolyzed and changed in quality in the presence of moisture. Described specifically, the transmittance of the polarizing layers41is made uneven or is reduced. The hydrolysis is further accelerated under heat. The adhered part is exposed to heat from the backlight1000. The polarizing layers41are therefore exposed to a severe environment, and their deterioration proceeds. This deterioration significantly affects the service life of the liquid crystal display device.

The present invention can solve such a problem as described above.

A liquid crystal display device according to the first embodiment of the present invention will hereinafter be described with reference toFIGS.5to8. In addition, first and second examples of a process for forming a third sealing layer of the liquid crystal display device according to the first embodiment of the present invention will hereinafter also be described with reference toFIGS.9to11andFIGS.12to14, respectively. It is to be noted that inFIGS.5to14, the same elements as those inFIGS.1to4are identified by the same reference numerals, and their description is omitted.FIG.5is a cross-sectional view of the liquid crystal display device according to the first embodiment.FIG.5corresponds to the III-III cross-sectional view ofFIG.1, that is,FIG.3.FIG.5is substantially different fromFIG.3in that the adhesion between the display panel10and the brightness control panel20is achieved by a third sealing layer130. The sealing layer in this adhered part will hereinafter be referred to as “the third sealing layer130,” while the sealing layer used for the adhesion between the first TFT substrate100and the first counter substrate200and the like in the display panel10will hereinafter be referred to as “the first sealing layer110,” and the sealing layer used for the adhesion between the second TFT substrate400and the second counter substrate500and the like in the brightness control panel20will hereinafter be referred to as “the second sealing layer120.”

A characteristic feature of the liquid crystal display device of the first embodiment shown inFIG.5is that the fourth polarizer40, adhesive layer70, and first polarizer50are protected from moisture in the outside air by the third sealing layer130. The third sealing layer130may be formed from a similar material as the first sealing layer110and the second sealing layer120. As the material of these sealing layers, an epoxy-based resin or an acrylic resin is preferably used. Still more preferably for the convenience of manufacturing, for the third sealing layer130, a resin for which ultraviolet (UV) curing and heat curing can be used in combination may be used. Examples of the resin for which ultraviolet (UV) curing and heat curing can be used in combination include resins formed by partially adding acrylate units to epoxy groups of epoxy-based resins, in other words, so-called partially acrylated epoxy resins and the like. Similar to the first sealing layer110and second sealing layer120, a resin that hardly allows permeation of moisture is also used for the third sealing layer130.

It is the thickness that is significantly different between the first and second sealing layers110and120and the third sealing layer130. The first and second sealing layers110and120have a thickness t4equal to the thickness of the first and second liquid crystal layers300and310, specifically, of approximately 3 μm, while the third sealing layer130has a thickness t5of, for example, approximately 400 μm because the third sealing layer130encloses the two polarizers40and50and the OCA70on an inner side thereof.

FIG.6is an enlarged fragmentary cross-sectional view showing on an enlarged scale the first to third sealing layers110,120, and130ofFIG.5. InFIG.6, the first and second light shielding layers202and204that define the frame areas of the display panel10and brightness control panel20, respectively, have the same width w1. The first and second sealing layers110and120have the same width w2and the same thickness t4. The width w2is formed to be small, and is 1 mm or smaller in many instances. The third sealing layer130that is for protecting the OCA70and the two polarizers40and50from the external environment has a width w3and a thickness t5.

The width w3of the third sealing layer130is formed to be greater than the width W2of the first and second sealing layers110and120to ensure the retention of a sufficient adhesive force. The third sealing layer130is large in the thickness t5, and therefore is large in cross-sectional area, so that the third sealing layer130is prone to allow the permeation of moisture correspondingly. It is hence also necessary for third sealing layer130to make moisture take a longer time to permeate it by forming the width w3greater than the width w2of the first and second sealing layers110and120.

It is however necessary to form the width w3of the third sealing layer130smaller than the width w1of the first and second light shielding layers202and204that define the frame areas, respectively. There is hence a relation of w1>w3>w2. There is also a relation of (the thickness t4of the first and second sealing layers110and120)<(the thickness t5of the third sealing layer130).

FIG.7is a plan view of the display panel10ofFIG.5. InFIG.7, the first TFT substrate100and the first counter substrate200are adhered together with the first sealing layer110. On a portion of the first counter substrate200where the first TFT substrate100and the first counter substrate200overlap each other, a display area160is formed, and a portion of the TFT substrate100where the TFT substrate100does not overlap the first counter substrate200is a first terminal area170. At the first terminal area170, two first driver ICs180are arranged. At the first terminal area170, a number of terminals is formed, and a flexible wiring substrate is connected to these terminals to supply power and signals to the display panel10. These terminals and flexible wiring substrate are however omitted inFIG.7.

InFIG.7, the part without the frame area serves as the display area160, and the width w1of the frame area is defined by the first light shielding layer202. The width of the first sealing layer110is w2. The third sealing layer130is formed on a lower side of the first TFT substrate100, and its width is w3.

At the display area160, scanlines1extend in a transverse direction (x-direction), and are aligned in a vertical direction (y-direction). Video signal lines2extend in the vertical direction, and are aligned in the transverse direction. At areas surrounded by the scanlines1and the video signal lines2, subpixels3are formed. To each subpixel3, any one of red color filters201R, green color filters201G, and blue color filters201B (seeFIG.5) formed on the first counter substrate200corresponds. Each pixel4is configured with three subpixels3. It is to be noted that on the first counter substrate200, the first light shielding layers202are formed corresponding to wirings to prevent reflection of light from the wirings.

FIG.8is a plan view of the brightness control panel20. The brightness control panel20has the same configuration as the display panel10except for some portions. InFIG.8, the second TFT substrate400and the second counter substrate500are adhered together with the second sealing layer120. At a display area162, scanlines1extend in the transverse direction (x-direction), and are aligned in the vertical direction (y-direction). Further, video signal lines21extend in the vertical direction, and are aligned in the transverse direction. At areas surrounded by the scanlines1and the video signal lines2, pixels4are formed.

InFIG.8, the pitch in the transverse direction of brightness signal lines21is three times the pitch in the transverse direction of the video signal lines2inFIG.7, and no subpixels are formed inFIG.8. In addition, no color filters are formed on the second counter substrate500of the brightness control panel20to increase the light transmittance. In the brightness control panel20, however, the second light shielding layers204are also formed, on the second counter substrate500, corresponding to the scanlines1and brightness signal lines21formed on the second TFT substrate400. These second light shielding layers204are for preventing the reflection of light from the wirings.

InFIGS.7and8, the video signal lines2and the brightness signal lines21both linearly extend in the vertical direction, that is, in the y-direction, but may extend in a zig-zag pattern depending on the product. In many instances, the zig-zag pattern is changed between the video signal lines2in the display panel10and the brightness signal lines21in the brightness control panel20.

InFIG.8, the width w1of the second light shielding layer204that defines the frame area, the width w2of the second sealing layer120that adheres the second TFT substrate400and the second counter substrate500together, and the width w3of the third sealing layer130that adheres the brightness control panel20and the display panel10together satisfy the following relation: w1>w3>w2as in the display panel10ofFIG.7. However, the third sealing layer130is formed on the second counter substrate500of the brightness control panel20(seeFIG.5).

According to the configurations of the first embodiment shown inFIGS.5to8, the penetration of moisture from the external environment can be prevented by the third sealing layer130as described above, and therefore the fourth polarizer40, fifth polarizer50, and OCA70can be prevented from absorbing moisture. It is therefore possible to prevent the deterioration of the polarizing layers41(seeFIG.4) of the polarizers40and by moisture and to prolong the service life of the liquid crystal display device.

It is to be noted that the thickness of the third sealing layer130is very large compared with the thickness of the first sealing layer110and second sealing layer120. A situation may therefore arise where the third sealing layer130cannot be formed in a similar manner as for the first sealing layer110and second sealing layer120.FIGS.9to11are cross-sectional views showing first to third steps of a first example of a process for forming the third sealing layer130.

FIG.9shows the first step of the first example. InFIG.9, the first polarizer50is adhered to a lower surface of the display panel10, and the fourth polarizer and OCA70are adhered to an upper surface of the brightness control panel20. The OCA70may be adhered to the first polarizer50on the side of the display panel10. The fourth polarizer40, first polarizer50, and OCA70have outer profiles shaped smaller than those of the display panel10and brightness control panel20.

FIG.10shows the second step that follows the first step ofFIG.9. InFIG.10, a resin for the third sealing layer130is applied from dispensers or by screen printing to a periphery of the display panel10, in other words, a portion of the display panel10where the first polarizer50does not exist. Further, the resin for the third sealing layer130is also applied from dispensers or by screen printing to a periphery of the brightness control panel20, in other words, a portion of the brightness control panel20where the fourth polarizer40and OCA70do not exist.

For the formation of the third sealing layers130, a resin for which UV curing and heat curing can be used in combination, for example, an acrylated epoxy resin can be used. As shown inFIG.10, after the resin for the third sealing layer130has been applied to both the periphery of the display panel10and the periphery of the brightness control panel20, the resin can be provisionally cured by being irradiated with ultraviolet rays.

FIG.11shows the third step that follows the second step ofFIG.10. As shown inFIG.11, the display panel10and the brightness control panel20are then adhered together with the provisionally cured third sealing layers130, followed by heat curing. According to this first example, the resin for the third sealing layer130is separately applied in two portions, one to the side of the display panel10, and the other to the side of the brightness control panel20, so that the third sealing layer130can be formed with good accuracy even if it has a large thickness. In addition, the fourth polarizer40, first polarizer50, and OCA70play a role as a spacer. Dispersion of a filler of very large particle size in the third sealing layer130is hence not needed, although such a filler would otherwise be needed to allow the third sealing layer130to act as a spacer.

In the above-described first example of the process for forming the third sealing layer130as shown inFIGS.9to11, OCA is used for the adhesive layer70that adheres the fourth polarizer40and the first polarizer50together. Without being limited to OCA, however, it may be configured to use a liquid adhesive and then to cure it.FIGS.12to14are cross-sectional views showing first to third steps of the second example of the process for forming the third sealing layer130of the liquid crystal display device ofFIG.5. For the formation of the third sealing layer130in the second example, a resin for which UV curing and heat curing can be used in combination, for example, an acrylated epoxy resin or the like is used as in the first example.

Before performing the first step ofFIG.12, the first polarizer50has been adhered to the lower surface of the display panel10, and the fourth polarizer40has adhered to the upper surface of the brightness control panel20. As shown inFIG.12, a resin for the third sealing layer3is then applied from dispensers or by screen printing to the periphery of the display panel10, in other words, a portion of the display panel10where the first polarizer50does not exist. Further, the resin for the third sealing layer130is also applied from dispensers or by screen printing to the periphery of the brightness control panel20, in other words, a portion of the brightness control panel20where the fourth polarizer40and OCA70do not exist.

On the side of the brightness control panel20inFIG.12, the height of the third sealing layer130is set to be greater by a predetermined amount h than that of the fourth polarizer40. This is to ensure formation of a space, in other words, a cavity on the inner side of the third sealing layer130and on the fourth polarizer40for use in pouring an adhesive, for example, an optical clear resin (OCR)72(seeFIG.13). The above-described predetermined amount h is, for example, 100 μm. InFIG.12, the resin for the third sealing layer130on the side of the display panel10and the resin for the third sealing layer130on the side of the brightness control panel20are irradiated with ultraviolet rays to be provisionally cured.

FIG.13shows the second step that follows the first step ofFIG.12. Described specifically,FIG.13shows how, on the side of the brightness control panel20, OCR72is poured by a one drop fill (ODF) method into the cavity formed by the third sealing layer130provisionally cured by the irradiation of ultraviolet rays as described above and having a depth h corresponding to the above-described predetermined amount h. From a plurality of dispensers600, a calculated amount of the OCR72is dropped. OCRs include silicone-based OCRs and acrylic OCRs, each of which is of the UV curing type and also of the heat curing type.

FIG.14shows the third step that follows the second step ofFIG.13. As shown inFIG.14, the display panel10and the brightness control panel20are adhered together with the provisionally cured third sealing layers130, followed by heat curing. At this time, the OCR72and the third sealing layer130are concurrently subjected to heat curing. In this second example, the resin for the third sealing layer130is separately applied in two portions, one to the side of the display panel10, and the other to the side of the brightness control panel20, so that the third sealing layer130can be formed with good accuracy even if it has a large thickness. In addition, the third sealing layer130semi-cured by ultraviolet rays can be used as a spacer when adhering the display panel10and the brightness control panel20together. Dispersion of a filler of very large particle size in the third sealing layer130is hence not needed, although such a filler would otherwise be needed to allow the third sealing layer130to act as a spacer. It is to be noted that ODF can also be performed on the side of the display panel10although ODF is performed on the side of the brightness control panel20in the second step.

According to the first embodiment, the fourth polarizer40, the adhesive layer70or72formed by the heat curing of the OCA or OCR, and the first polarizer50can be protected from moisture in the adhered part of the display panel10and the brightness control panel20as described above. The liquid crystal display device according to the first embodiment is therefore excellent in contrast and high in reliability.

FIG.15is a cross-sectional view of a liquid crystal display device according to the second embodiment of the present invention. InFIG.15, the same elements as those inFIG.5are identified by the same reference numerals, and their description is omitted. In the above-described first embodiment, the OCA or OCR is used as the adhesive layer70to72along with the third sealing layer3in the adhered part of the display panel10and the brightness control panel20. To allow the OCA or OCR to exhibit its function as an adhesive layer, a certain amount of thickness is needed. In the second embodiment, the third sealing layer130is assigned with a role to adhere the display panel10and the brightness control panel20together, and, for example, a high refractive oil80is used as a layer, which is assigned with only a role for optical coupling, instead of an adhesive layer between the fourth polarizer40and the first polarizer50.

The display panel10and brightness control panel20have the same configurations as in the first embodiment. It is the use of the high refractive oil80instead of the OCA70between the fourth polarizer40and the first polarizer50thatFIG.15is different fromFIG.5of the first embodiment. The high refractive oil80is sealed by the third sealing layer130. As no adhesive function is needed for the high refractive oil80, the layer of the high refractive oil80can be formed with as small a thickness as possible to an extent that can form the layer as a uniform layer, and may be, for example, 5 μm.

The high refractive oil80is used with a purpose of improving the optical coupling between the brightness control panel20and the display panel10, specifically the optical coupling between the fourth polarizer40and the first polarizer50.

As the layer of the high refractive oil80can be formed to be thin, the disparity due to parallax between the display panel10and the brightness control panel20can be reduced compared with the use of the adhesive layer70or72of the OCA or OCR in the first embodiment. Owing to the small layer thickness, the high refractive oil80can also reduce the amount of moisture to be contained therein. In addition, the thickness of the third sealing layer130can also be reduced by making thinner the layer of the high refractive oil80. The amount of moisture that would permeate through the third sealing layer130can also be decreased. Moreover, it is possible to choose, as a high refractive oil, a material that absorbs moisture in a smaller amount than the OCA or the like. Accordingly, the deterioration of the polarizing layers of the fourth polarizer40and first polarizer50in the presence of moisture can also be reduced further.

In view of the refractive index of glass used as the TFT substrates and counter substrates and the refractive index of the polarizers, the refractive index of the high refractive oil80is preferably 1.43 to 1.55 or so, with 1.48 to 1.52 being more preferred. As such a high refractive oil, immersion oil can be exemplified. Immersion oil is used, for example, by filling it between an objective lens and a cover glass to substantially increase the aperture ratio of the lens. As immersion oil, a variety of products is marketed from diverse optical equipment manufacturers. The refractive index of immersion oil is 1.52 in general.

As a process that enables the formation of the third sealing layer130of the liquid crystal display device according to the second embodiment shown inFIG.15, it is possible to use a process similar to the second example of the process for forming the third sealing layer130of the liquid crystal display device according to the first embodiment. In the second embodiment, the thickness of the layer of the high refractive oil80is smaller compared with the thickness of the adhesive layer70or72of OCA or OCR in the first embodiment, and can therefore be set to be smaller than the depth h inFIG.13. This can correspondingly facilitate the manufacture of the liquid crystal display device of the second embodiment.

As described above, the liquid crystal display device according to the second embodiment can form high contrast images, and can be provided with high reliability.