The present technology described herein relates to a liquid crystal display device including a liquid crystal panel and a backlight.
A liquid crystal display device generally includes a liquid crystal panel, a front surface side polarizing plate, a rear surface side polarizing plate, and a backlight. The liquid crystal panel includes two transparent substrates and a liquid crystal layer enclosing liquid crystals between the two transparent substrates to have an alignment control area where alignment of the liquid crystals can be controlled. The front surface side polarizing plate is disposed opposite a front surface of the liquid crystal panel. The rear surface side polarizing plate is disposed opposite a rear surface of the liquid crystal panel. The backlight is disposed opposite a surface of the rear surface side polarizing plate that is not opposite the liquid crystal panel. In such a liquid crystal display device of a related art, one of methods of fixing the front surface side polarizing plate, the liquid crystal panel, the rear surface side polarizing plate, and the backlight each other is disclosed in Japanese Unexamined Patent Application Publication No. 2012-103687.
Japanese Unexamined Patent Application Publication No. 2012-103687 discloses an optical adhesive film used for a flat panel display module for displaying an image that includes a transmission part that is disposed on the flat panel display module for transmitting an image; and a blade part extending from one end of the transmission part for covering a side face of the flat panel display module and covering a part of a back face of the flat panel display module. The transmission part spontaneously adheres to a front face of the flat panel display module and the blade part spontaneously adheres to the side face and the back face of the flat panel display module.
The liquid crystal display device described in Patent Document 1 includes the optical adhesive film between the front surface side polarizing plate and the liquid crystal panel. Therefore, brightness of a displayed image is decreased according to the light transmittance of the optical adhesive film. Further, a thickness of the liquid crystal display device is increased by a thickness of the optical adhesive film. Furthermore, the method of producing the liquid crystal display device described in Patent Document 1 requires a process of attaching the optical adhesive film, and this increases a production cost. The present technology was made in view of the above circumstances and an object is to provide a liquid crystal display device that is high in brightness of a displayed image and has small thickness and a low production cost.
To solve the above problem, according to one aspect of the present technology, a liquid crystal display device includes a liquid crystal panel including two transparent substrates and a liquid crystal layer enclosing liquid crystals between the two transparent substrates, the liquid crystal panel having an alignment control region in which alignment of the liquid crystals is controlled, a polarizing plate disposed opposite a back surface of the liquid crystal panel, a backlight disposed opposite a surface of the polarizing plate that is not opposite the liquid crystal panel and supplying light to the polarizing plate, and an optical film including a front surface section and an extended section, the front surface section being disposed on a front surface of the liquid crystal panel, and the extended section extending from one edge of the front surface section and attached to at least a part of a side surface of the backlight or at least a part of a back surface of the backlight, and the front surface section includes in a part thereof a polarizing section that polarizes transmission light and the polarizing section overlaps the alignment control region.
According to the liquid crystal display device having such a configuration, the polarizing plate, the alignment control region, and the polarizing section are stacked on each other. Therefore, transmittance of light can be controlled based on the alignment direction of the liquid crystals. Therefore, light exiting through the backlight passes through the polarizing plate, the alignment control region and the polarizing section, and the brightness is varied according to the transmittance of the light. Accordingly, the brightness of a display screen can be controlled. Various images may appear on the display screen according to a purpose of the display screen.
According to the liquid crystal display device of the present technology, brightness of a displayed image is increased, a thickness of the device is decreased, and a production cost is reduced.
<Liquid Crystal Display Device 100>
<Liquid Crystal Panel 140>
The liquid crystal panel 140 includes two quadrangular transparent substrates and a liquid crystal layer that is between the two transparent substrates. The liquid crystal layer includes liquid crystals that are sealed with sealing material. The liquid crystal panel 140 has a plate shape. Material of the two transparent substrates is glass but may be other material such as plastic. Electrodes are arranged on a liquid crystal layer side section of the two transparent substrates and a potential difference therebetween can be controlled. The liquid crystals are aligned in a specific direction by the application of the potential difference between the electrodes. An alignment film may be provided on the liquid crystal layer side of the transparent substrate such that the liquid crystals are aligned in a certain direction when no potential difference is created between the electrodes. A spacer may provided to keep a constant distance between the two transparent substrates. The electrodes may be formed in any shape. For example, the electrodes may have an electrode pattern arrayed in a regular form or an electrode pattern of a graphic pattern, a character, or a picture. The alignment direction of the liquid crystals may be various directions such as a vertical alignment or a horizontal alignment. A transistor component may be included to control the potential difference between the electrodes.
Between the two transparent substrates, the front surface side transparent substrate has a long-side dimension that is small- than a long-side dimension of the back surface side transparent substrate. A front surface of one of the short-side sections of the back surface side transparent substrate is exposed outside. The liquid crystal layer is not disposed on the exposed section and a wiring 160 is connected thereto. Electric signals for controlling the alignment of the liquid crystals included in the liquid crystal panel 140 are transferred to the liquid crystal panel 140 through the wiring 160. The wiring 160 is a flexible circuit board including a flexible board and conductors printed thereon. The liquid crystal panel 140 controls the potential difference between the electrodes based on the electric signals supplied to the conductors of the wiring 160.
The liquid crystal panel 140 includes an alignment control region 141 where the alignment of the liquid crystals can be controlled. The liquid crystal layer is in the alignment control region 141 seen from the front surface side and an electric field is created by the potential difference in the region. The alignment control region has a quadrangular shape seen from the front surface side and is in a middle of the liquid crystal panel 140.
<Polarizing Plate 130>
The polarizing plate 130 is a flat plate having substantially same size and shape as the alignment control region 141 or slightly greater than that. The polarizing plate 130 has a function of polarizing light passing through a thickness thereof. The polarizing plate 130 of the present embodiment includes a polarizing layer and a protection layer. The polarizing layer is made of polyvinyl alcohol (PVA) as a main material has a polarizing function. The protection layer is disposed on front and back surfaces of the polarizing layer. The protection layer is a layer of one of triacetylcellulose (TAO), polyethylene terephthalate (PET), polypropylene (PP), and acrylic resin (resin containing poly (methyl methacrylate) as a main component) or a layer of mixture or stacking layers of two or more of triacetylcellulose, polyethylene terephthalate, polypropylene, and acrylic resin. However, the material is not limited to the above. The polarizing plate 130 is disposed opposite the back surface of the liquid crystal panel 140 to cover the alignment control region 141 with a pressure sensitive adhesive layer or an adhesive layer.
<Backlight 110>
The backlight 110 has a quadrangular plate shape having a substantially same shape as that of the liquid crystal panel 140 seen from the front surface side. The backlight 110 includes a light exit region 111 through which the light exits. The light exit region 111 preferably has a substantially same shape as that of the alignment control region 141 seen from the front surface side. A region of the front surface of the backlight 110 that is outside the light exit region 111 is referred to as a frame region 112. The backlight 110 is disposed opposite a surface of the polarizing plate 130 that is not opposite the liquid crystal panel 140, that is, disposed opposite a back surface.
<Adhesive Tape 120>
The backlight 110 and the liquid crystal panel 140 are fixed to each other with the adhesive tape 120. The adhesive tape 120 has a quadrangular shape having a quadrangular hole in a middle thereof and has a frame shape. The polarizing plate 130 is arranged in the hole. The front surface of the adhesive tape 120 adheres to a section of the back surface of the liquid crystal panel 140 and outside the alignment control region 141. The back surface of the adhesive tape 120 adheres to the frame region 112 of the backlight 10. The adhesive tape 120 at least fixes the liquid crystal panel 140 and the backlight 110 and may not be formed in the frame shape. For example, four side sections of the frame region 112 may be fixed with thin and long strips of adhesive tapes or only a part of the frame region 112 may be fixed with the adhesive tape. Further, as long as the liquid crystal panel 140 and the backlight 110 are fixed to each other effectively, fixing means other than the adhesive tape 120 such as fixing with screws may be used. If the liquid crystal panel 140 and the backlight 110 are effectively fixed to each other only with the optical film 150, which will be described later, such fixing means is not necessary.
<Optical Film 150>
As illustrated in
The polarizing section 151 has a function of polarizing the light passing through the thickness of the optical film 150. The polarizing section 151 has a quadrangular shape having a substantially same size and shape as or greater than those of the alignment control region 141 seen from the back surface side so as to cover the alignment control region 141.
The optical film 150 is foldable at a border between the front surface section 152 and the extended section 153 and at a section of the extended section 153. As illustrated in
A configuration of the optical film 150 will be described with reference to
The first protection layer 155 is preferably made of material that is transparent with respect to visible light and has certain tensile strength, hardness, a chemical resistance property, an ultraviolet absorbing property, and flexibility. Specifically, examples of the material include one of triacetylcellulose, polyethylene terephthalate, polypropylene, and acrylic resin or a layer of mixture or stacking layers of two or more of triacetylcellulose, polyethylene terephthalate, polypropylene, and acrylic resin. A surface of the first protection layer may be subjected to a hard coating process, an antiglare process, a low reflection process, and an antistatic process, if necessary.
The adhesive layer 154 is disposed on the back surface side of the first protection layer 155. As is described before, the adhesive layer 154 is used for bonding the optical film 150 to the liquid crystal panel 140 and the backlight 110. The adhesive layer 154 may be an adhesive layer.
In a section of the optical film 150 corresponding to the polarizing section 151, the polarizing layer 156 is bonded to the front surface of the first protection layer 155 with adhesive. The polarizing layer 156 has a function of polarizing the light that passes through the thickness of the polarizing layer 156. Specifically, the polarizing layer 156 is preferably made of material obtained by absorbing and aligning iodine (I) compound in polyvinyl alcohol.
Further, the second protection layer 157 is bonded to the front surface of the polarizing layer 156 with adhesive. The second protection layer 157 is preferably made of material that is transparent with respect to visible light and has certain tensile strength, hardness, a chemical resistance property, an ultraviolet absorbing property, and flexibility. Specifically, examples of the material include one of triacetylcellulose, polyethylene terephthalate, polypropylene, and acrylic resin or a layer of mixture or stacking layers of two or more of triacetylcellulose, polyethylene terephthalate, polypropylene, and acrylic resin. A surface of the first protection layer may be subjected to a hard coating process, an antiglare process, a low reflection process, and an antistatic process, if necessary.
<Advantageous Effects of the Present Embodiment>
According to the liquid crystal display device 100 according to the present embodiment, the polarizing plate 130, the alignment control region 141, and the polarizing section 151 are stacked on (overlapped with) each other. Therefore, transmittance of light can be controlled based on the alignment direction of the liquid crystals. Therefore, light exiting through the light exit region 111 of the backlight 110 passes through the polarizing plate 130, the alignment control region 141 and the polarizing section 151, and the brightness of exiting light is varied according to the transmittance of the light. Accordingly, the brightness of the display screen can be controlled. The region through which the light exits with controlled brightness is referred to as a display screen 170. Various images may appear on the display screen 170 according to a purpose of the display screen.
The optical film 150 is folded to extend and adhere to the front surface of the liquid crystal panel 140 and the side surface 113 of the backlight 110. Therefore, the liquid crystal panel 140 and the backlight 110 are fixed to each other with a simple and lightweight structure. The optical film 150 is folded to extend to the back surface 114 of the backlight 110 such that the liquid crystal panel 140 and the backlight 110 are fixed to each other more firmly.
The extended section 153 may not be folded at the back surface side edge of the backlight 110 so as to be contacted with the back surface 114. The extended section 153 may not be fixed to the back surface 114 of the backlight 110. In such a configuration, the extended section 153 may be smaller and this leads to decrease in weight, thickness, and cost. Furthermore, the production process is simplified and this leads to cost reduction.
According to the configuration of bonding the extended section 153 to the back surface 114 of the backlight, the liquid crystal panel 140 and the backlight 110 are fixed to each other and therefore, the extended section 153 may not be necessary to be fixed to the side surface 113 of the backlight. In such a configuration, the extended section 153 provided on the side surface does not necessarily include the adhesive layer 154 and this may lead to decrease in size, weight, and cost.
The front surface side polarizing plate and the optical adhesive film are integrally formed into the optical film 150. Therefore, the liquid crystal display device can be decreased in thickness, weight, and cost compared to a configuration including a front surface side polarizing plate and an optical adhesive film as separate components. Further, compared to an optical film obtained by overlapping the front surface side polarizing plate and the optical adhesive film, the optical film of the present embodiment has higher transmittance and therefore, brightness of the display screen 170 can be increased and the power consumption is reduced.
The extended section 153 does not include the polarizing layer 156 and/or the second protection layer 157. Therefore, the extended section 153 is easy to be folded and is light and thin. Therefore, the process of folding the extended section 153 is easy and the liquid crystal display device 100 is thinner and lighter. The front surface section 152 may have the polarizing layer 156 and/or the second protection layer 157 over an entire area thereof. The extended section 153 may have the polarizing layer 156 and/or the second protection layer 157 on a part thereof or an entire area thereof. In such a configuration, producing and attachment of the optical film 150 may become easier or the optical film 150 may be stronger. The entire front surface area of the liquid crystal display device 100 is a flat surface and the display screen 170 is less likely to be distinguished from the section around the display screen 170 where no image is displayed and this improves design.
The alignment control region 141 of the liquid crystal panel 140, the polarizing plate 130, the light exit region 111 of the backlight 110, and the polarizing section 151 of the optical film 150 may at least have an overlapping area seen from the front surface side and do not necessarily have the same shape and do not necessarily have a quadrangular shape. However, if the alignment control region 141 of the liquid crystal panel 140, the polarizing plate 130, the light exit region 111 of the backlight 110, and the polarizing section 151 of the optical film 150 may have a substantially same shape and overlap each other over substantially entire areas seen from the front surface side, a non-overlapping area is decreased. As a result, an area of the display screen 170 is increased and the area around the display screen 170 where no image is displayed is decreased and such a configuration is more preferable.
Further, the optical film 250 includes a light blocking layer 258 on the front surface of the first protection layer 155 in an area having no polarizing layer 156. A large amount of the visible light rays supplied to the light blocking layer 258 do not transmit therethrough. The light blocking layer may be a light absorbing layer or a light reflection layer or may have a multilayer structure including the light reflection layer and the light absorbing layer. Most of the visible light rays supplied to the light blocking absorbing layer are absorbed by the light absorbing layer and the light absorbing layer is preferably formed by coating black ink. Most of the visible light rays supplied to the light reflection layer are reflected by the light reflection layer and a typical example thereof may be an aluminum thin film.
According to the present embodiment, the light exiting the backlight 110 is reflected and refracted within the liquid crystal display device 200 and stray light may be created and such stray light is less likely to exit the liquid crystal display device 200 through sections other than the display screen 170.
The light blocking layer 258 may not be necessarily formed on an entire area having no polarizing layer 156. However, the light blocking layer 258 is preferably formed on the entire area having no polarizing layer 156. According to the configuration including the light blocking layer 258 on the entire area having no polarizing layer 156, the stray light is further less likely to exit through the sections other than the display screen 170. According to the configuration including the light blocking layer 258 on only a part of the area having no polarizing layer 156, the device may be reduced in weight, thickness, and a cost.
The light blocking layer 258 is preferably not formed on a front side of the polarizing layer 156. According to the configuration not including the light blocking layer 258 on the front side of the polarizing layer 156, the entire area having the polarizing layer 156 can be used as the display screen 170 of the liquid crystal display device 200. The light blocking layer 258 may be formed on the front side of the polarizing layer 156. In designing of such a configuration, the polarizing layer 156 and the light blocking layer 258 may overlap each other. Therefore, even if the position of the polarizing layer 156 or the light blocking layer 258 is shifted in the production process, an area having no polarizing layer 156 and no light blocking layer 258 is less likely to be created and the stray light is less likely to exit outside.
The light blocking layer 258 that is made of material having conductivity such as an aluminum thin film has an effect of protection against electromagnetic wave. Further, the light blocking layer 258 that is made of material having high light reflectance such as an aluminum thin film can reflect the stray light toward the inner side of the liquid crystal display device 200. This increases brightness of the display screen 170. Further, if material having high light absorbing rate such as black ink is disposed on the front surface of the material having high light reflectance (on an outer side of the liquid crystal display device 200), the stray light is further less likely to exit outside.
The optical film 350 of the present embodiment includes extended sections 353 extending from three sides of the front surface section 152. The extended sections 353 are attached to three side surfaces of the liquid crystal panel 140 where the wiring 160 is not connected, the three side surfaces 113 and the back surface 114 of the backlight 110.
According to the present embodiment, the optical film 350 is attached to the three side surfaces of the liquid crystal panel 140 where the wiring 160 is not connected, the three side surfaces 113 and the back surface 114 of the backlight 110. Therefore, the liquid crystal panel 140 and the backlight 110 are fixed to each other more firmly. The extended sections 353 may have a light blocking layer thereon and accordingly, the stray light is blocked more surely.
As illustrated in
According to the present embodiment, the optical film 650 is attached to the four side surfaces of the liquid crystal panel 140 and the four side surfaces 113 and the back surface 114 of the backlight 110. Therefore, the liquid crystal panel 140 and the backlight 110 are fixed to each other more firmly. Further, the recess 659 corresponds to the opening of the liquid crystal display device 600 and the wiring 160 passes through the opening such that the wiring 160 connected to the liquid crystal panel 140 extends to the outside of the liquid crystal display device 600. Further, a light blocking layer may be provided in a section of the optical film 150 having no polarizing layer. In such a configuration, the stray light can be blocked more surely. The wiring 160 may not be the one connected to the liquid crystal panel 140 but may be connected to the backlight 110 or may be disposed on the front surface side of the liquid crystal panel 140 and the back surface side of the front surface section and connected to a touch panel.
According to the present embodiment, in the liquid crystal panel 140 having a short side section and/or a long side section where the wiring 160 is connected, the wiring 160 can extend to the outside of the liquid crystal panel 140. Multiple wirings 160 can extend outside the liquid crystal panel 140. In the present embodiment, two wirings 160 are connected to one of the short side sections of the liquid crystal panel 140 and three wirings 160 are connected to one of the long side sections of the liquid crystal panel 140. However, the sections of the liquid crystal panel 140 where the wirings 160 are connected are not limited to the above sections. For example, the wirings 160 may be connected to opposing two side sections of the liquid crystal panel 140 or may be connected to three side sections or four side sections. The number of the wirings 160 is not limited but necessarily one or more.
A liquid crystal panel according to the present embodiment has an outline having a substantially same shape as or slightly smaller than the shape of the front surface section 852 seen from the front surface side. The alignment control region of the liquid crystal panel has a substantially same shape as that of the polarizing section 851. The section of the liquid crystal panel that corresponds to a back surface of the transparent window may be or may not be the alignment control region. The outline of a polarizing plate of the present embodiment is a substantially same shape as that of the polarizing section 851 seen from the front surface side. The section of the polarizing plate that is positioned on the back surface side of the transparent window 881 does not have the function of polarizing the transmission light. The backlight is disposed on the back surface side of the polarizing plate. The backlight has a substantially same shape as or slightly smaller than that of the front surface section 852. The backlight does not include a reflector, a diffuser, or a chassis on the section on the back surface side of the transparent window 881.
According to the present embodiment, in the transparent window 881, the sections of optical film 850 and the polarizing plate positioned on the back surface side of the optical film 850 do not have a function of polarizing the transmission light. Therefore, even if the alignment direction of the liquid crystals of the liquid crystal panel is controlled, the transmittance of the light rays transmitting through the optical film 850, the liquid crystal panel, and the polarizing plate is high and is less likely to change. In the backlight disposed on the back surface side of the polarizing plate, a section that is on the back surface side of the transparent window 881 does not include the reflector, the diffuser and the chassis. Therefore, the backlight can be seen through to the rear surface side thereof. The section of the polarizing plate that is positioned on the back surface side of the transparent window 881 may be formed in a hole.
In the present embodiment, not only the front surface section 952 but also the liquid crystal panel, the polarizing plate, and the backlight that are disposed on the back surface side of the front surface section 952 are provided with round corners at the four corner of the vertically elongated quadrangular shape and a recess is formed in the section corresponding to the recess 982.
According to the present embodiment, the liquid crystal display device 900 is formed into a quadrangular shape having round corners R. Further, the recess 982 is formed in the device. The display screen is formed into a quadrangular shape having round corners. The recess is formed in the display screen. Since the outline of the liquid crystal display device 900 seen from the front surface side is similar to the shape of the display screen, most area of the front surface of the liquid crystal display device 900 can be used as the display screen. The shape and the number of the recesses 982, the size of the corner R, and a ratio of a vertical dimension and a horizontal dimension of a whole device may be altered in design as necessary.
A liquid crystal panel is disposed on the back surface side of the optical film 1050. The liquid crystal panel has a substantially regular twelve-sided polygonal shape seen from the front surface side similar to the front surface section 1052 and has a through hole at a center thereof. The alignment control region has a circular shape similar to that of the polarizing section 1051. A polarizing plate is disposed on the back surface side of the liquid crystal panel. The polarizing plate has a substantially circular shape seen from the front surface side and has a through hole at a center thereof. A backlight is disposed on the back surface side of the polarizing plate. The backlight has a substantially regular twelve-sided polygonal shape seen from the front surface side similar to that of the front surface section 1052. The front surface section 1052 has a through hole at a center thereof.
According to the present embodiment, the liquid crystal display device 1000 has a regular twelve-sided polygonal shape and the display screen may have a circular shape. Further, the liquid crystal display device 1000 has the through hole 1083. Further, the recess 1058 corresponds to a circular hole and the wiring 1060 having a circular cross section can extend through the hole. The shape of the liquid crystal display device 1000 seen from the front surface may be other regular polygonal shape instead of the regular twelve-sided polygonal shape. The through hole 1083 may be multiple through holes 1083. Multiple recesses 1058 may be provided and multiple wirings 1060 may be provided.
According to the present embodiment, the optical film 1150, which includes the front surface section 1152 disposed on the front surface of the liquid crystal panel 140, is folded to be attached to the side surface 113 of the backlight 110. Accordingly, the liquid crystal panel 140 and the backlight 110 are fixed to each other with a simple and lightweight structure. Further, the optical film 1150 is folded and extended and attached to the back surface 114 of the backlight 110. The liquid crystal panel 140 and the backlight 110 are fixed to each other more firmly.
An adhesive layer may be provided on the back surface of the second protection layer such that the second protection layer may be bonded to the front surface of the liquid crystal panel 140. In such a configuration, the liquid crystal panel 140 and the backlight 110 are fixed to each other more firmly. An adhesive layer may be provided in an area that is included in the front surface section 1152 but not in the polarizing section 1151. In such a configuration, the liquid crystal panel 140 and the backlight 110 are fixed to each other more firmly. The second protection layer 1157 may not be provided and this may lead to reduction in thickness, weight, and a cost of the liquid crystal display device 1100 and increase in brightness thereof. In the configuration without having the second protection layer 1157, an adhesive layer may be provided on the back surface of the polarizing layer 1156 and in such a configuration, the liquid crystal panel 140 and the backlight 110 are fixed to each other more firmly. A light blocking layer may be provided in an area not including the polarizing layer 1156 and in such a configuration, stray light is less likely to leak outside.
This application claims priority from U.S. Provisional Application No. 62/682,702 filed on Jun. 8, 2018. The entire contents of the priority application are incorporated herein by reference.
Number | Date | Country | |
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62682702 | Jun 2018 | US |