Patent Application
20120314144
(1) Field of the Invention
The present invention relates to a display device, and in particular to a liquid crystal lens type three-dimensional display device where a liquid crystal display panel having a lens function is provided on the display side of a display panel for displaying an image.
(2) Description of the Related Art
Display devices where a two-dimensional (2D) display and a three-dimensional (3D) display, which can be seen with the naked eye, that is to say, without using any glasses, can be switched with each other are formed of, for example, a first liquid crystal display panel for displaying an image and a second liquid crystal display panel that is provided on the display side (viewer side) of the first liquid crystal display panel and forms a parallax barrier for allowing different rays to enter the left and right eyes of the viewer at the time of a 3D display. In these liquid crystal display devices where a 2D display and a 3D display can be switched with each other, the alignment of liquid crystal molecules in the second liquid crystal display panel is controlled so that the refractive index in the second liquid crystal display panel is changed so as to form lens regions (lenticular lens, cylindrical lens array) which run in the upward and downward directions and are aligned in the left and right directions on the display, and thus, light beams from pixels are directed along the visual line so as to correspond to the left and right eyes separately in the configuration.
Liquid crystal lens type three-dimensional display devices having the above-described structure include, for example, the three-dimensional image display device in JP 2010-224191A. This display device in JP 2010-224191A has such a structure that electrodes in comb form are respectively formed on a pair of transparent substrates, upper and lower, which are placed so as to face each other with a liquid crystal layer in between. In this structure, a voltage applied across the electrodes on the upper and lower transparent substrates can be controlled so as to make it possible to switch the 2D display and the 3D display, and at the same time, the parallax number at the time of the 3D display can be controlled.
In order for the second liquid crystal display panel to effectively function as a liquid crystal lens, the height (thickness) of the liquid crystal layer, that is to say, the gap between the first substrate (upper transparent substrate) and the second substrate (lower transparent substrate), needs to be approximately 20 μm to 100 μm, and thus, a gap that is wider than that in the first liquid crystal display panel is required. In order to secure such a wide gap, spacer members, such as spacer beads, of which the size is greater than that in the first liquid crystal display panel for displaying an image are required.
In the case where such spacer beads having a large diameter are used as spacer members, a large area is occupied by the spacer beads in a plane in the second liquid crystal display panel, and therefore, the ratio of light that transmits through the spacer beads from among the display light emitted from the first liquid crystal display panel is high. When the display light that has reached a spacer bead enters into or leaves from the spacer bead, the light that transmits after refraction from the interface between the liquid crystal layer and the spacer bead and the light that is reflected from the interface are separated, and the lights are respectively emitted from the second liquid crystal display panel as display light.
In particular, in the second liquid crystal display panel where the 2D display and the 3D display can be switched with each other, the refractive index of the liquid crystal layer is controlled by the electrical field applied across the comb-shaped electrodes and the common electrodes, and thus, a cylindrical lens array is formed. Meanwhile, the refractive index of the spacer beads is inherent to the material that forms the spacer beads, and thus does not change. As a result, when the 2D display and the 3D display are switched with each other, the refractive index in the vicinity of the comb-shaped electrodes changes greatly.
Therefore, the difference in the refractive index between a spacer bead and the liquid crystal layer is great in the case where the spacer bead is placed in the vicinity of a comb-shaped electrode. As a result, the refractive angle and the reflection of the display light are great in the interface between the spacer bead and the liquid crystal layer, which makes light scattering great, and therefore, such a problem arises that the viewer sees the spacer bead, which lowers the display quality. Furthermore, large spacer beads disturb the alignment of the liquid crystal, and thus, there is such a concern that the lens performance may be reduced at the time of the 3D display.
The present invention is provided in light of these problems, and an object of the present invention is to provide a display device where the display quality can be high both at the time of the 2D display and the 3D display.
In order to solve the above-described problems, the display device according to the present invention has: a display panel for displaying an image; and a liquid crystal lens panel for switching a 2D display and a 3D display with each other, which is provided on the display side of the above-described display panel and forms a parallax barrier by controlling the refractive index as in a cylindrical lens, wherein the above-described liquid crystal lens panel has: a pair of transparent substrates that are placed so as to face each other with a liquid crystal layer in between; comb-shaped electrodes, which are formed on the liquid crystal layer side of one of the above-described transparent substrates, run in the X direction, and are aligned in the Y direction; flat common electrodes formed on the liquid crystal layer side of the other of the above-described transparent substrates; and post spacers having light transmitting properties for holding the above-described pair of transparent substrates at a predetermined distance, wherein the above-described post spacers are fixed to one of the above-described pair of transparent substrates on the liquid crystal side and are placed in regions away from the above-described comb-shaped electrodes in a plane of the above-described transparent substrate.
According to the present invention, the display quality at the time of the 2D display and the 3D display can be improved.
The other effects of the present invention will be clarified from the entire description of the specification.
In the following, the embodiments of the present invention are described in reference to the drawings. In the following descriptions, the same symbols are attached to the same components, and the descriptions thereof are not repeated. In addition, X, Y and Z in the figures respectively indicate the X axis, the Y axis and the Z axis.
The liquid crystal display device according to the first embodiment is formed of a first liquid crystal display panel LCD1, which is a liquid crystal display panel for displaying an image, and a second liquid crystal display panel LCD2 that functions as a lens (lenticular lens, cylindrical lens array) by controlling the refractive index for transmission light. In the liquid crystal display device that has this structure according to the first embodiment as shown in
A member made of a well-known resin material having approximately the same refractive index as the transparent substrates (glass substrates) used as the first substrate SUB11 or SUB 21 and the second substrate SUB12 or SUB22 is used as the adhesive member ADH. In addition, the first liquid crystal display panel LCD1 and the backlight unit BLU have well-known structures, and thus, optical sheets, such as a diffuser plate, are not shown. Furthermore, the structure may be provided with a well-known protective film, a front plate and a well-known touch panel on the display side of the second substrate SUB22.
The second liquid crystal display panel LCD2 according to the first embodiment is formed of a liquid crystal display panel, for example, where liquid crystal molecules are homogeneously aligned and a pair of transparent substrates (first substrate SUB21, second substrate SUB22), such as glass substrates, are placed so as to face each other as in a well-known manner so that liquid crystal LC2 is sandwiched between the first substrate SUB21 and the second substrate SUB22. In addition, a comb-shaped electrode (first electrode, connected long, rectangular strips) is formed on the first substrate SUB21, and a common electrode (second electrode) is formed on the second substrate SUB22 in such a manner that no electrical field is applied to the liquid crystal layer LC2 when the comb-shaped electrode and the common electrode are in the same potential, and in this state, display light (display image) from the first liquid crystal display panel LCD1 transmits (passes) as it is for 2D display. In the case where different voltages are applied to the first and second electrodes, that is a so-called alternating voltage is applied while an electrical field is applied to the liquid crystal layer LC2, a parallax barrier for providing a parallax between the two eyes, where the display light from the first liquid crystal display panel LCD1 enters separately to the left and right eyes of the viewer, is provided as a lens function for 3D display (3D display for the naked eye). In this manner, the second liquid crystal display panel LCD2 according to the first embodiment operates as a liquid crystal display panel for allowing the incident light (display light) to transmit as it is in the state where no electrical field is applied to the liquid crystal. Here, the second liquid crystal display panel LCD2 is not limited to having a homogeneous alignment, but may be of another type.
The first liquid crystal display panel LCD1 according to the first embodiment is a liquid crystal display panel of a well-known IPS (in-plane switching) type and has such a structure that a pair of transparent substrates (first substrate SUB 11, second substrate SUB12), such as glass substrates, are placed in a well-known manner so as to face each other with a liquid crystal layer LC1 in between. Thin film transistors, pixel electrodes and a common electrode are formed in a well-known manner on the first substrate SUB11, and color filters and a black matrix are formed in a well-known manner on the second substrate SUB12. Here, the first substrate SUB11 is formed of a transparent substrate that is larger than the second substrate SUB12, and connection terminals for the connection to the outside are formed in a peripheral portion of the transparent substrate. As for the pasting of the first substrate SUB11 and the second substrate SUB12 together and the sealing of the liquid crystal, a well-known sealing material applied in annular form around the periphery of the second substrate SUB12 is used to paste the first and second substrates together, and this is also used to seal the liquid crystal. Furthermore, a first polarizing plate PLO1 is provided on the first substrate SUB11 on the backlight device side (on the surface facing the surface on the liquid crystal side) and a second polarizing plate PLO2 is provided on the second substrate SUB12 on the display side (on the surface facing the surface on the liquid crystal side) in such a manner that the directions of polarization of the first polarizing plate PLO1 and the second polarizing plate PLO2 form an angle of 90°. Here, the first liquid crystal display panel LCD1 is not limited to an IPS type liquid crystal display panel, but may have a structure where another type of liquid crystal display panel, such as of a TN type or a VA (vertical alignment) type, is used.
As shown in
Each sub-pixel SPL is provided with a thin film transistor, not shown, that is turned on by a scanning signal from the gate line GL and a pixel electrode that is connected to the source electrode of the thin film transistor so that a gradation signal (gradation voltage) is supplied from the drain line DL through the thin film transistor when turned on. In the case of an IPS type liquid crystal display panel, a common electrode, to which a common signal having a potential that becomes the reference for the potential of the gradation signal is supplied, is provided on the first substrate SUB11 on the side where the thin film transistors are formed. In the case of a VA type or TN type liquid crystal display panel, however, a common electrode is formed on the second substrate SUB12 together with the color filters.
In the liquid crystal display panel LCD1 according to the first embodiment, the region where pixels PXL for color display are formed of sub-pixels for red (R), green (G) and blue (B) within the region where liquid crystal is sealed becomes a display area. Thus, the region where no pixels are formed and which does not relate to the display does not become a display area even within the region where liquid crystal is sealed.
<Structure of Second Liquid Crystal Display Panel>
As shown in
At this time, the display light from the first liquid crystal display panel LCD1, that is to say, the light that has passed through the second polarizing plate POL2, is in the direction indicated by arrow F1 in the figure, and this display light enters into the second liquid crystal display panel LCD2. Accordingly, the direction in which the light (display light) that enters into the second liquid crystal display panel LCD2 is polarized (direction in which incident light is polarized) is at 80° to 90° relative to the comb teeth electrodes PX. In addition, the liquid crystal molecules in the liquid crystal layer LC2 are aligned so as to be approximately parallel to this direction in which the incident light is polarized F1 so that attenuation of the display light when passing through the second liquid crystal display panel LCD2 can be reduced. Accordingly, a rubbing process (alignment process) for aligning the liquid crystal molecules in the liquid crystal layer LC2 approximately parallel to the direction in which the incident light is polarized is carried out on the second liquid crystal display panel LCD2. As a result, the rubbing angle in the second liquid crystal display panel LCD2 is 80° to 90° relative to the comb teeth electrodes PX so that the direction of the long axes of the liquid crystal molecules in the liquid crystal layer LC2 is aligned in the direction in which the incident light is polarized, as indicated by arrow F1. In addition, the refractive index of the liquid crystal molecules in the direction of the long axes, that is to say, in the direction of alignment, is no, as indicated by arrow F2 in the figure, and the refractive index in the direction perpendicular to this is no.
As described above, in the liquid crystal display device according to the first embodiment, the direction in which the light that enters into the second liquid crystal display panel LCD2 is polarized (direction of the transmission axis of the second polarizing plate POL2) is at an angle of 0° to 10° relative to the direction along a long side (X direction) of the second liquid crystal display panel LCD2 in which cylindrical lenses are aligned. In the case where the direction in which the light that enters into the second liquid crystal display panel LCD2 is polarized is in a desired direction as a result of linear polarization, the display mode of the first liquid crystal display panel LCD1 is not limited. In the case where the direction of polarization of the first liquid crystal display panel LCD1 is different from the desired direction as a result of linear polarization, the present invention can be applied by providing a well-known phase difference member between the second polarizing plate POL2 and the second liquid crystal display panel LCD2 so that light is polarized in a desired direction as a result of linear polarization, for example.
Post spacers PS, which are spacer members for holding the distance between the first substrate SUB21 and the second substrate SUB22 (gaps) to a predetermined value (approximately 20 μm to 100 μm), are formed in the direction in which the comb teeth electrodes PX run, that is to say, in the Y direction, in the regions between the comb teeth electrodes PX which are aligned in the X direction. These post spacers PS are formed of a photosensitive resin material, which is a material having photosensitivity, and placed in every other region between two comb teeth electrodes PX in the X direction in the structure in the first embodiment. In particular, the post spacers PS are located approximately at the center of each region between adjacent comb teeth electrodes PX in the X direction in which the comb teeth electrodes PX are aligned in order for the distance between each comb tooth electrode PX and each post spacer PS to be large. In addition, the post spacers PS in the first embodiment are placed so as to have approximately the same distance therebetween in the direction in which the comb teeth electrodes PX run, that is to say, in the Y direction, as in the X direction in order for the post spacers PS to be provided with a density as low as possible within such a range as to provide such a strength that the gap between the first substrate SUB21 and the second substrate SUB22 can be maintained. As described above, the post spacers PS are periodically placed in the structure so that it is made difficult for the viewer to see the post spacers PS.
In the case where the post spacers PS are arranged periodically, the period in the X direction Px is NQ when the period in the X direction is Px (here, N is a natural number, desirably 3 to 10, and Q is the period (pitch) of the comb teeth electrodes PX). In the case where the period in the Y direction Py is NQ, which is the same as the period in the X direction, the relative relationship between the post spacers and the pixels in the display panel are the same in the X and Y directions, which is desirable. Furthermore, Py may be equal to MQ (here, M is a natural number, desirably 3 to 10, and M≠N). In the case where there is interference between the post spacer and the pixels in the first liquid crystal display panel LCD1 due to the period in the Y direction, M may be a real number. Furthermore, the post spacers PS may be placed at random. Likewise, N may not be constant so as to be varied at random depending on the location. That is to say, the arrangement of the comb teeth electrodes PX and the spacer members SP is not limited to the structure shown in
In addition, each post spacer PS is in a square column form of which the shape in the cross-section parallel to the display, that is to say, the main surface of the first substrate SUB21, is square and is placed so that a pair of sidewalls that face each other from among the sidewalls of the post spacers PS is approximately in the same direction as in the direction in which the alignment film is rubbed. That is to say, as shown in
As shown in
At the time of 3D display using the second liquid crystal display panel LCD2 according to the first embodiment in the above-described structure, cylindrical lenses that run in the Y direction in regions between the comb teeth electrodes PX that are adjacent to each other are formed, and thus, an array of cylindrical lenses in lenticular form that are aligned in the X direction is formed. Here, the region in the second liquid crystal display panel LCD2 where the cylindrical lens array is formed corresponds to the display area in the first liquid crystal display panel LCD1. As a result, it is possible to direct light from different pixels, that is to say, images for different viewpoints, separately to the two eyes, left and right, of the viewer in the case where the two eyes are aligned in the X direction, and thus, stereovision is made possible in the liquid crystal display device according to the first embodiment.
<2D Display Operation and 3D Display Operation>
In the following, the display operation in the liquid crystal display device according to the first embodiment is described in reference to
In the second liquid crystal display panel LCD2 according to the first embodiment, as shown in
At the time of 2D display, where the difference in the potential between the comb teeth electrodes PX and the common electrode CT is 0 volts, that is to say, the same voltage is applied to the comb teeth electrodes PX and the common electrode CT, as shown in
Meanwhile, as shown in
In the case of two viewpoints, pixels PXL (R) for the right eye and pixels PXL (L) for the left eye are alternately aligned in the direction in which the cylindrical lenses are aligned. As a result, as indicated by the arrow in
<Detailed Structure of Post Spacers>
As shown in
Meanwhile, color filters for R, G and B, not shown, are formed on the second substrate SUB22, which is arranged so as to face the first substrate SUB21 with the liquid crystal layer LC2 in between, on the liquid crystal side, and furthermore, a light blocking film, such as a well-known black matrix, is also formed if necessary. The common electrode CT is formed in a layer above these color filters or the black matrix, that is to say, on the second substrate SUB22 on the liquid crystal side, and an alignment film ORI is formed so as to cover the common electrode CT. Here, post spacers PS may be formed only on the second substrate SUB22 in the structure.
The refractive index in the second liquid crystal display panel LCD2 in the first embodiment having the above-described structure is ne, which is constant in a range from the section −Q/2 to the section Q/2, that is to say, in the entire region as is clearly shown by graph G1 in
Meanwhile, at the time of 3D display where different voltages are applied to the comb teeth electrodes PX and the common electrode CT so that an electrical field is applied through the liquid crystal layer LC2, the refractive index is distributed symmetrically relative to the X direction (between left and right in the figure) with the location 0 at the center, as is clear from graph G2, and thus, a cylindrical lens that runs in the Y direction is formed.
In the sections P3 and P4, which are the sections away from the comb teeth electrodes PX, that is to say, in the vicinity of the center point “0” between the pair of comb teeth electrodes PX (in the vicinity of the optical axis of the cylindrical lens) in particular, liquid crystal molecules stay lying even at the time of 3D display, as is clear from
In the regions between section −Q/2 and section P1 as well as between section P2 and section Q/2, the comb teeth electrodes PX and the common electrode CT face each other with the liquid crystal layer LC2 in between. Accordingly, at the time of 3D display, liquid crystal molecules stand in the vicinity of the comb teeth electrodes PX due to the electrical field applied across the comb teeth electrodes PX and the common electrode CT, which makes the refractive index smaller. As a result, the refractive index in the portions above the comb teeth electrodes PX has a value close to that of the refractive index no. At this time, disclination, that is to say, disturbance in the alignment of liquid crystal molecules, easily occurs in the vicinity of the comb teeth electrodes PX, and this disturbance in the alignment makes the distribution of the refractive index complex.
In the second liquid crystal display panel LCD2 in the first embodiment, it is more difficult to see the post spacers 2 both at the time of 2D display and at the time of 3D display when the refractive index nsp of the post spacers PS has a value close to that of the refractive index ne of the liquid crystal so that the difference in the refractive index is small. Particularly when the refractive index of the post spacers PS is smaller than ne, total reflection occurs in the interface between the post spacers PS and the liquid crystal, which makes it easy to see the post spacers PS. The angle at which a light beam enters into a post spacer PS that is placed at the center of the liquid crystal lens from an end of a pixel is approximately 5° to 8°, and the refractive index ne of the liquid crystal that is used in the liquid crystal display panel LCD2 is approximately 1.7, and therefore, it is desirable for the difference between the refractive index nps of the post spacers PS and the refractive index ne of the liquid crystal layer LC2 to be 0.24 or less, and it is more desirable for it to be 0.15 or less in order to prevent a light beam that enters into a post spacer PS located at the center of the liquid crystal lens from an end of a pixel from causing a total reflection. Furthermore, the angle at which a light beam enters into a post spacer PS placed at the center of the liquid crystal lens from the center of the pixel is approximately 2.5° to 4°, and therefore, it is desirable for the difference between the refractive index nps of the post spacers PS and the refractive index ne of the liquid crystal layer LC2 to be 0.12 or less, and it is more desirable for it to be 0.07 or less in order to prevent a light beam that enters into a post spacer PS placed at the center of the liquid crystal lens from the center of the pixel from causing a total reflection.
<Shape of Post Spacers PS in Cross-Section>
As is clear from
In the case where the display light in the post spacers PS (indicated by arrow K1 in
In the case where the refractive index nps of the post spacers PS is greater than the refractive index ne of the liquid crystal layer LC2, the ratio of light K1 that has entered into the post spacers PS and has reached the interface being reflected from the interface increases. Furthermore, there is a critical angle for a total reflection of light K1 that has reached the interface in such a manner that light K1 that has hit the interface at an incident angle no smaller than this critical angle is totally deflected, and light that has hit at an incident angle no greater than the critical angle is refracted at a large angle, and thus, light is greatly scattered in the vicinity of the post spacers PS. In particular, the bottom (width 5) of the post spacers PS is greater than the top (width S1). Therefore, in the case where the light that has entered into the post spacers PS is greatly reflected from the interface, the light inside the post spacers PS is collected on the top side so as to exit through the top side, which is brighter than the surrounding area. Furthermore, regions S2 and S3 within the regions in the vicinity of the post spacers PS are particularly darker than the peripheral area outside of these. As a result, in the case where the refractive index nps of the post spacers PS is greater than the refractive index ne of the liquid crystal layer LC2, the post spacers PS can be easily seen, and at the same time, the display quality at the time of 2D display and at the time of 3D display lowers due to light scattering. In order to prevent these effects and improve the display quality, it is preferable for the refractive index nps of the post spacers PS to be no greater than the refractive index ne of the liquid crystal layer LC2.
As shown in
Though the post spacers PS in the first embodiment have such a structure that the size (thickness) varies between the top side and the bottom side, it is desirable for the entire portion ranging from the top side to the bottom side to vary a little. When the size varies a little in this manner, it is possible to reduce light scattering from the post spacers PS. As a result, the display quality at the time of 2D display and at the time of 3D display can be improved. In addition, cross talk of the display light at the time of 3D display, that is to say, cross talk between the display light for the right eye and the display light for the left eye, can be reduced, and thus, the 3D display quality can be improved.
In addition, the post spacers PS are formed in regions between the comb teeth electrodes PX that are aligned next to each other, that is to say, in regions through which the display light from the first liquid crystal display panel LCD1 transmits, and therefore, it is desirable for the thickness of the post spacers PS, in particular, the width S in the X direction, to be smaller. Furthermore, it is desirable for the aspect ratio, which is the ratio of the height of the post spacers PS to the width S in the X direction, to be greater.
The post spacers PS having the above-described structure can be formed of a well-known light sensitive material, and therefore can be formed using a well-known photolithographic technology. Here, the post spacers 2 may be formed through printing, such as screen printing or ink jet printing.
Though post spacers PS having a rectangular shape in a cross-section are described in the second liquid crystal display panel LCD2 in the first embodiment, there are no limitations to this, and cylindrical post spacers may be used in the structure, for example. In addition, an alignment process may be carried out on the sidewalls of the post spacers PS in the structure.
As described above, the display device according to the first embodiment is formed in such a manner that the second liquid crystal display panel LCD2 is provided on the first liquid crystal display panel LCD1 for displaying an image in accordance with an external video signal on the display side. The second liquid crystal display panel LCD2 is formed of a first substrate SUB21 and a second substrate SUB22 that are placed so as to face each other with a liquid crystal layer LC2 in between. Comb teeth electrodes that run in the Y direction and are aligned in the X direction, which crosses the Y direction, are formed on the first substrate SUB21, and one end of each comb tooth electrode is electrically connected to a wire formed along a side of the first substrate SUB21. Furthermore, post spacers PS are formed in regions away from the comb teeth electrodes, and the post spacers PS have a refractive index nps similar to the refractive ne of the liquid crystal layer LC2 in the structure. As a result, it is possible to make smaller the difference in the refractive index between the post spacers PS and the liquid crystal layer LC2 at the time of 2D display and at the time of 3D display, that is to say, the difference in the refractive index between the two sides of the interface, and thus, light scattering from the interface can be greatly suppressed. As a result, the post spacers PS can be prevented from being seen by the viewer, and at the same time, the display quality at the time of 2D display and at the time of 3D display can be improved. Furthermore, light scattering from the post spacers PS can be suppressed, and thus, the 3D display quality can be improved.
Furthermore, the second liquid crystal display panel LCD2 in the first embodiment is formed such that the post spacers PS are formed in locations away from the comb teeth electrodes PX, and therefore, such particular effects can be gained that it is possible to prevent the alignment of liquid crystal molecules from being disturbed in the vicinity of the comb teeth electrodes PX due to the post spacers PS and the display quality can further be improved.
Though the second liquid crystal display panel LCD2 in the first embodiment is formed in such a manner that the post spacers PS are aligned in the direction in which the comb teeth electrodes PX run (Y direction), the alignment of the post spacers PS is not limited to this. As shown in
As shown in
As described above, according to the present invention, spacer beads SB are placed in locations away from the comb teeth electrodes PX, that is to say, in regions where the refractive index changes a little at the time of 2D display and at the time of 3D display, and at the same time, the spacer beads SB are formed of a material having a similar refractive index to that of the liquid crystal when no voltage is applied. As a result, the image quality can be prevented from lowering when spacer beads SB for supporting the gap that is greater than that in the first liquid crystal display panel LCD1, which is a liquid crystal display panel for display, are provided.
At this time, in the second liquid crystal display panel LCD2 in the second embodiment, it is possible to place the spacer beads SB in desired locations, which are locations away from the comb teeth electrodes PX, by forming the spacer beads SB using an ink jet printer or providing the spacer beads SB using a printing technique, such as screen printing. In the case where an ink jet printer is used to form spacer beads SB in the center portions between pairs of comb teeth electrodes PX, that is to say, in the center regions of the cylindrical lenses (in the vicinity of optical axes of cylindrical lenses), for example, the ink jet printer is used to form spacer beads SB directly onto the main surface of the first substrate SUB21. Here, the method for providing spacer beads SB to the center regions between the comb teeth electrodes PX is not limited to this. Another example is a method for securing spacer beads SB to desired locations by scattering spacer beads PS after forming adhesive members for spacer beads SB in locations in which the spacer beads SB are to be placed by means of an ink jet printer or screen printing.
In addition, the spacer beads SB in the second embodiment are also formed of a resin material having a refractive index similar to the refractive index ne of the liquid crystal as the post spacers PS in the first embodiment.
As described above, the second liquid crystal display panel LCD2 in the second embodiment is also formed in such a manner that spacer beads SB having a refractive index similar to that of the liquid crystal LC2 are provided in the vicinity of the optical axes of the cylindrical lenses, and therefore, the same effects as in the first embodiment can be gained. In addition, no photographic processes for forming and providing spacer beads SB are required in the second liquid crystal display panel LCD2 in the second embodiment, and therefore, such particular effects that the second liquid crystal display panel LCD2 can be easily manufactured can be gained.
As is clear from
In the same manner as in the first embodiment, the post spacers PS1 and PS2 are formed between adjacent comb teeth electrodes PX, and in particular, in regions away from the comb teeth electrodes PX, which is in the vicinity of the centers between the comb teeth electrodes PX in the X direction. That is to say, the post spacers PS2 are formed in such locations as to face the post spacers PS1, and the upper surface of the post spacers PS1 and the upper surface of the post spacers PS2 make contact with each other when the first substrate SUB21 and the second substrate SUB22 are pasted together, and thus, the gap between the first substrate SUB21 and the second substrate SUB22 is maintained at a predetermined distance. Here, the post spacers PS1 and PS2 are both made of a translucent material having a refractive index of ne.
In particular, as shown in
As described above, the second liquid crystal display panel LCD2 in the third embodiment is formed so as to maintain the gap between the first substrate SUB21 and the second substrate SUB22 at a predetermined distance by using the two types of post spacers PS, the post spacers PS1 formed on the first substrate SUB21 and the post spacers PS2 formed on the second substrate SUB22. This structure makes it possible for the post spacers PS1 and PS2 formed on the first substrate SUB21 and on the second substrate SUB22 to have a height half of the gap. As a result, it is possible to shorten the time required for the formation of the post spacers PS1 and PS2 that require a height corresponding to the gap in the second liquid crystal display panel LCD2, which is greater than the gap in the first liquid display panel LCD1. Furthermore, in the case where a rubbing process is carried out on the alignment film ORI after the formation of the post spacers PS1 and PS2, it is possible for a smaller force to be applied to the post spacers PS1 and PS2, and therefore, it is possible to increase the reliability of the post spacers PS1 and PS2.
Furthermore, two types of post spacers PS1 and PS2 are layered on top of each other in order to maintain the gap in the structure of the third embodiment, even though the post spacers PS1 and PS2 are formed in such a manner that the sidewalls incline at the same angle as that in the first embodiment. Accordingly, it is possible for the post spacers PS1 and PS2 to have a smaller volume without expanding the area of the post spacers PS1 and PS2 in a plane.
In the case where the post spacers PS in the first embodiment and the post spacers PS1 and PS2 in the third embodiment have the same aspect ratio, the area for installing post spacers can be reduced by providing post spacers with a shorter height. In the third embodiment, post spacers PS1 and PS2 are provided to the upper and lower substrates (first substrate SUB21 and second substrate SUB22) in the structure. Accordingly, the height of the post spacers PS1 and PS2 can be ½ of that of the post spacers PS in the first embodiment, where
As in the first embodiment, the direction in which the display light from the first liquid crystal display panel LCD1 is polarized (the direction in which the incident light to the second liquid crystal display panel LCD2 is polarized) is at 80° to 90° relative to the comb teeth electrodes PX in the second liquid crystal display panel LCD2 in the third embodiment, as indicated by the arrow in the figure. That is to say, the first substrate SUB21 is formed such that the direction of the initial alignment is the same as in the direction in which the incident light is polarized. At this time, the refractive index of the liquid crystal layer LC2 is ne, even in the case where the electrical field between the comb teeth electrodes PX and the common electrode CT is zero, and the refractive index in the vicinity of the comb teeth electrodes PX is no when an electrical field is applied.
Though the post spacers PS1 and PS2 in the third embodiment are formed such that the area on the bottom is greater than that on the top, the structure is not limited to this, and one or both of the post spacers PS1 and PS2 may be formed such that the area on the top is greater than that on the bottom. Though the height of the post spacers PS1 and the height of the post spacers PS2 are the same in the above description, the structure is not limited to this, and they may have different heights.
As is clear from
In addition, the first substrate SUB21 in the fourth embodiment is formed such that part of the common electrode CT1 is located in each region between adjacent comb teeth electrodes PX1. At this time, an alignment film ORI is formed in a layer above the common electrode CT1, and post spacers PS1 are formed on the upper surface of the alignment film ORI in the structure. Here, the post spacers PS1 in the fourth embodiment have the same shape as those in the third embodiment and are formed in such locations as to face the below-described post spacers PS2.
Meanwhile, the second substrate SUB22 in the fourth embodiment is formed such that comb teeth electrodes PX2 run in the longitudinal direction, that is to say, the X direction, and are aligned in the width direction, that is to say, the Y direction, and a wire portion WR2 is provided along a side of the second substrate SUB22 and runs in the Y direction, where one end of each comb tooth electrodes PX2 is electrically connected to the wire portion WR2. In addition, in the same manner as in the first substrate SUB21, a common electrode CT2 is formed in the region excluding the region in which the comb teeth electrodes PX2 and the wire portion WR2 are formed, at least within the display area, where the common electrode CT2 is formed in the same layer as the comb teeth electrodes PX2 and the wire portion WR2. That is to say, in the same manner as in the first substrate SUB21, part of the common electrode CT2 is formed in each region between adjacent comb teeth electrodes PX2 in the structure. The second substrate SUB22 is also formed such that an alignment film ORI is formed in a layer above the common electrode CT2, and post spacers PS2 are formed on the upper surface of the alignment film ORI in such locations as to face the post spacers PS1. The post spacers PS2 have the same shape as those in the third embodiment.
As is clear from
As shown in
As is clear from
In order to make this switching possible, the second liquid crystal display panel LCD2 in the fourth embodiment is formed such that comb teeth electrodes PX1 are aligned in the width direction (X direction) of the post spacers PS1 formed on the first substrate SUB21 and the comb teeth electrodes PX1 run in the longitudinal direction (Y direction) of the post spacers PS1. Meanwhile, comb teeth electrodes PX2 are aligned in the width direction (Y direction) of the post spacers PS2 formed on the second substrate SUB22 and the comb teeth electrodes PX2 run in the longitudinal direction (X direction) of the post spacers PS2 in the structure. Furthermore, common electrodes CT1 and CT2 are formed on the first substrate SUB21 and the second substrate SUB22, respectively, in the structure. The thus-formed first substrate SUB21 and second substrate SUB22 are placed so as to face each other with a liquid crystal layer LC2 in between so that 3D display is possible in the longitudinal direction and in the width direction.
At the time of 3D display in the longitudinal direction (lateral position), for example, a common signal which works as a reference is supplied to the common electrode CT2 and the comb teeth electrodes PX2 formed on the second substrate SUB22, and at the same time, a drive signal is supplied to the comb teeth electrodes PX1 formed on the first substrate SUB21. As a result of this operation, as in the above-described first to third embodiments, cylindrical lenses are formed between adjacent comb teeth electrodes PX1 so as to run in the direction in which the comb teeth electrodes PX1 run (Y direction) and be aligned in the X direction. At this time, neither the common signal nor the drive signal is supplied to the common electrode CT1 formed on the first substrate SUB21.
Meanwhile, at the time of 3D display in the width direction (longitudinal position), a common signal which works as a reference is supplied to the common electrode CT1 and the comb teeth electrodes PX1 formed on the first substrate SUB21, and at the same time, a drive signal is supplied to the comb teeth electrodes PX1 on the first substrate SUB21. As a result of this operation, cylindrical lenses are formed between adjacent comb teeth electrodes PX2 so as to run in the direction in which the comb teeth electrodes PX2 run (Y direction) and be aligned in the Y direction. At this time, neither the common signal nor the drive signal is supplied to the common electrode CT2 formed on the second substrate SUB22 in the structure.
Thus, in the second liquid crystal display panel LCD2 in the fourth embodiment, in the same manner as in the second liquid crystal display panel LCD2 in the third embodiment, post spacers PS1 and PS2 are formed in the center locations that are away from the adjacent comb teeth electrodes PX1 and PX2 in the structure, and therefore, the same effects as in the third embodiment can be gained. In addition, comb teeth electrodes PX1 and PX2 are formed on the first substrate SUB21 and the second substrate SUB22 in the structure, and therefore, particular effects can be gained such that 3D display is possible in either direction of the display device, the longitudinal direction and the width direction.
Though the comb teeth electrodes PX1, the wire portion WR1 and the common electrode CT1 are formed in the same layer in the fourth embodiment, the structure is not limited to this. The comb teeth electrodes PX1 and the wire portion WR1 may be formed in a layer different from the common electrode CT1 with an insulating film in between in the structure in such a manner that the comb teeth electrodes PX1 and the wire portion WR1 are formed closer to the liquid crystal layer LC2 than the common electrode CT1, for example. In this structure, it is possible for the common electrode CT1 to be formed on the entire surface within the display area on the first substrate SUB21.
As shown in
In the case where the present invention is applied to a portable phone MP, post spacers can be prevented from being seen by the viewer both at the time of 3D display at the longitudinal position where the longitudinal direction of the display device DIS is in the upward and downward direction, as shown in
Though the display device according to the fifth embodiment of the present invention is applied to an information apparatus, the invention is not limited to this, and it is possible to apply the display device according to the present invention to other apparatuses having a display device, such as photographing devices for taking 3-dimensional videos or a television device.
Though the invention made by the present inventor is concretely described on the basis of the above-described embodiments of the invention, the present invention is not limited to these embodiments of the invention, and various modifications are possible as long as the gist of the invention is not deviated from.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-127002 | Jun 2011 | JP | national |
The present application claims priority over Japanese application JP 2011-127002 filed on Jun. 7, 2011, the contents of which are hereby incorporated into this application by reference.
