JP2008309963A - Liquid crystal display device equipped with microlens array - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device which provides stereoscopic display for naked eyes, is advantageous to a manufacturing operation, and is equipped with a high-quality microlens array. <P>SOLUTION: The liquid crystal display device comprises a liquid crystal interposed in a cell surrounded by two substrates placed opposite to each other. The lens array for the stereoscopic vision arranged so as to match with a plurality of pixels is disposed on the display surface side of the liquid crystal display device. The lens array is formed by offset printing. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device provided with a microlens array for autostereoscopic viewing as a light beam control element.

  The display can observe a stereoscopic image without an observer using a special device such as glasses. There are various types of autostereoscopic display systems such as the lenticular system and the holographic system, but the basic principle of most of the systems is that the right and left sides are controlled by controlling the light information incident on the eyes of the observer. Different light information is incident on the eyes to realize autostereoscopic viewing. One of the autostereoscopic display systems described above is an integral photography system described in Non-Patent Document 1. This integral photography system is configured by a lens array composed of a large number of lenses as disclosed in Patent Document 1. The integral photography method is a method in which a light spot is generated at an arbitrary place by a plurality of lenses, and there are a plurality of pixels under each lens, and one of the pixels displays the light spot. When the lens array is viewed from the viewpoint A, the pixel A can be seen through each lens, and when viewed from the viewpoint B, the pixel B can be seen through each lens. Is possible.

  By combining this lens array with an image display device, it is possible to construct an autostereoscopic display. As a method of forming a lens array on a liquid crystal display device, Patent Document 2 discloses a clean printing method.

JP 2006-235415 A JP 2005-308973 A T.A. Koike, etal. , MoireReductionforIntegralVideography, ProceedingsofThe13thInternationalDisplayWorksshops (IDW2006), 3D4-4L, 2006

  In screen printing, ink is printed on the substrate between the mesh stitches and through the stencil. When the plate is removed from the substrate after printing, the mesh is extracted from the ink printed on the substrate. There is a drawback that bubbles remain at the position where the mesh intersects and the performance of the lens array of the three-dimensional image display lens is poor. In addition, after printing, the printed ink waits for the surface tension to become a nearly smooth spherical surface, and is irradiated with light to cure. However, the ink leaks during this waiting time, and the circle collapses or is connected to the adjacent ink. In this case, there is a disadvantage that a high-performance lens array is not formed because the spherical surface is not accurate.

  Also, in screen printing, the plate comes into contact with the printing surface while being extended by the squeegee of the printing press, so even if the printing plate can be designed with high accuracy, the plate pattern is printed in a deformed state. The shape of the printed matter and the printing position cannot be maintained with high accuracy.

  Moreover, it is necessary to leave under a reduced pressure for a predetermined time after printing to remove bubbles inside the curable resin ink, and there is a disadvantage that the manufacturing time is long.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides a liquid crystal display device capable of autostereoscopic viewing, which is advantageous in the manufacturing process and includes a high-quality lens array.

  In order to solve the above problem, in the present invention, offset printing is used for forming the lens array.

  The present invention is, for example, a liquid crystal display device in which a liquid crystal is sandwiched between cells surrounded by two opposing substrates, and the display surface side of the liquid crystal display device corresponds to a plurality of pixels. A lens array for stereoscopic viewing is arranged. The lens array is formed by offset printing.

  Further, a light shielding pattern formed by offset printing may be formed between the lenses constituting the lens array.

  Hereinafter, examples of embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a plan view of a liquid crystal display device 100 to which the present embodiment is applied. The front side of the drawing is the observer side (display surface side). FIG. 2 is a cross-sectional view of the liquid crystal display device 100 and corresponds to the cross section AA ′ of FIG.

  The liquid crystal display device 100 of the present embodiment has the same configuration as that of a normal liquid crystal display device except that it includes a microlens array 70 for stereoscopic viewing. The liquid crystal display device of the present embodiment is a transmissive liquid crystal display device that transmits and displays the backlight from the backlight module 80. However, it may be a transflective liquid crystal display device including a reflective display unit that receives and reflects external light for display.

  Further, the present invention can be applied to various types of liquid crystal display devices such as a TN (Twisted Nematic) method, a VA (Virtical Alignment) method, and an IPS (In-Place-Switching) method.

  As shown in FIG. 2, the liquid crystal display device 100 includes a microlens array 70, an external optical film (polarizing plate, retardation plate, etc.) 10, a color filter substrate 20, and a liquid crystal layer 40 in order from the display surface side. A TFT (thin film transistor) substrate 50, an external optical film (polarizing plate, retardation plate, etc.) 60, and a backlight module 80.

  The liquid crystal layer 40 is sealed between the color filter substrate 20 and the TFT substrate 50 by the seal portion 30.

  The color filter substrate 20 is formed with a black matrix and colored resists (R (red), G (green), and B (blue)). Further, the common electrode 21 is formed on the main surface side (the liquid crystal layer 40 side), and an alignment film for aligning the liquid crystal layer 40 is formed on the common electrode 21. The common electrode 21 is a transparent electrode such as an ITO film.

  On the TFT substrate 50, pixel electrodes 51, which are transparent electrodes, are arranged in a matrix. Each pixel electrode 51 corresponds to one of R, G, and B of the color filter substrate 20 and becomes a pixel region (sub-pixel region). The pixel electrode 51 is connected to a TFT (thin film transistor) formed at a portion where the scanning line and the signal line intersect.

  In the case of an IPS system that generates lateral charges, the common electrode 21 is formed with an insulating film sandwiched between lower layers of the pixel electrodes 51 provided on the TFT substrate 50 side. In such a case, the pixel electrode 51 includes, for example, a slit-shaped opening.

  The microlens array 70 is directly formed on the external optical film (for example, polarizing plate) 10 on the color filter substrate 20 side. The microlens array 70 is a convex hemispherical lens group. Each lens is arranged so as to correspond to a plurality of pixels, and allows different images to be incident on the left and right eyes of the observer to enable stereoscopic viewing.

  The diameter W of each lens of the microlens array 70 is in the range of 100 to 600 μm, and the pitch d between the lens ends is in the range of 10 to 40 μm. The lens height h is about 1/10 of the lens diameter W and is in the range of 10-60 μm.

  Such a microlens array 70 can be formed by an offset printing technique described later.

  As long as stereoscopic vision is possible, there is no limitation on the shape (diameter W, height h, etc.) and arrangement (pitch interval d, etc.) of each lens constituting the microlens array 70. For example, they may be arranged in a square lattice pattern, or closest packing or delta arrangement may be employed to increase the number of light control elements. Further, each lens is not limited to a circle, but may be a hexagon. Moreover, a cylindrical lens may be used.

  3 to 8 are diagrams showing a process of forming the microlens array 70. FIG. In the present embodiment, the microlens array 70 is formed using an offset printing method. By using the offset printing method, it is possible to form the microlens array 70 having a desired pitch end interval d and lens height h.

  As shown in FIGS. 3 and 4, first, the lens material 203 is imprinted by the doctor blade 204 onto the intaglio plate 201 in which the depression 202 is formed corresponding to the pattern (lens pattern) of the microlens array 70. Here, the height h of the formed lens can be adjusted by adjusting the depth of the recess 202.

  As the lens material 203, a UV (ultraviolet) curable polymer material or a thermosetting polymer material that is cured by heating at 100 ° C. or less can be used. As the entire polymer, an acrylic polymer, an epoxy polymer, an acrylic epoxy polymer, or the like can be used.

  Next, as shown in FIG. 5, a transfer roller 301 having a blanket 302 around it is rolled on the intaglio 201, and as shown in FIG. 6, a lens material 203 is attached to the blanket 302 to transfer the lens pattern. .

  Here, the liquid crystal cell 110 (see FIG. 2) is prepared in a state where the color filter substrate 20 and the TFT substrate 50 are bonded together by sealing the liquid crystal layer 40 and the external optical films 10 and 60 are bonded together.

  Then, as shown in FIG. 7, the liquid crystal cell 110 is fixed to the surface plate of the offset printing machine with the external optical film 10 on the color filter substrate 20 side as the upper surface. Further, as shown in FIGS. 7 and 8, the transfer roller 301 to which the lens material 203 is attached is rolled on the upper surface of the external optical film 10. Thereby, the lens material 203 can be attached to the external film 10, and the lens pattern transferred to the transfer roller 301 can be transferred to the external film 10. When the lens material 203 is separated from the transfer roller 301, the surface of the lens material 203 is rounded by a peeling force. This roundness causes a lens action.

  Finally, the lens material 203 transferred to the external film 10 is subjected to UV light irradiation treatment, heat treatment, or a combination thereof depending on the material to cure the lens material 203. As a result, the microlens array 70 having a desired pitch interval and height is formed.

  Note that, when it is desired to increase the radius of curvature, offset printing may be performed in a plurality of times in order to obtain a desired lens height. For example, after a lens material having a predetermined height is applied in the first printing, the lens pattern is further overlapped by offset printing. In this way, a lens having a desired height can be easily formed.

  After the microlens array 70 is formed, the backlight module 80 is fixed.

  The liquid crystal display device to which the present invention is applied and the characteristic manufacturing process thereof have been described above.

  According to the present embodiment, since the offset printing technique is used, a high-quality lens can be easily formed. Accordingly, it is possible to manufacture a liquid crystal display device that can be stereoscopically viewed at low cost and with high yield.

<Second Embodiment>
The liquid crystal display device of the second embodiment basically has the same configuration as that of the first embodiment. Therefore, the description of the same configuration (denoted by the same symbol) is omitted. In the liquid crystal display device of this embodiment, a light shielding pattern is formed between the lenses constituting the microlens array 70.

  FIG. 9 is a plan view of a liquid crystal display device 101 to which the present embodiment is applied. The front side of the drawing is the display surface side. FIG. 10 is a cross-sectional view of the liquid crystal display device 101 and corresponds to the A-A ′ cross section of FIG. 9.

  As shown in the figure, on the display surface side of the liquid crystal display device 100, a light shielding pattern 75 and a microlens array 70 are formed in the opening on the external polarizing plate 10. The microlens array 70 is the same as that of the first embodiment.

  The light shielding pattern 75 can be formed by the offset printing technique described in the first embodiment.

  The material of the light shielding pattern 75 is a material obtained by kneading carbon black with a UV curable polymer material or a thermosetting polymer material that is cured by heating at 100 ° C. or less. As the polymer itself, acrylic, epoxy, and acrylic epoxy polymers can be used.

  First, the material of the light shielding pattern 75 is applied on the optical film 10 by offset printing. The light shielding pattern 75 includes a circular opening at a portion where the microlens 70 is formed. Thereafter, in the same manner as in the first embodiment, the material of the microlens array 70 is applied to the opening of the light shielding pattern 75.

  The application of the material of the light shielding pattern 75 and the application of the material of the microlens array 70 can be continuously transferred and printed without performing UV light irradiation and heat treatment between the processes. The light shielding pattern 75 does not require a certain height like a lens, and can be formed by one offset printing.

  The transferred light-shielding pattern 75 and microlens array 70 pattern are subjected to UV light irradiation and heat treatment alone or in combination depending on the material to cure the material.

  Thus, a liquid crystal display device including the light shielding pattern 75 and the microlens array 70 as shown in FIGS. 9 and 10 is completed.

  According to the liquid crystal display device 101 of the present embodiment, since the light shielding pattern 75 exists between the lenses of the microlens 70, it is possible to prevent the transmitted light from leaking between the lenses.

<Third Embodiment>
FIG. 11 is a cross-sectional view of a liquid crystal display device 102 including a microlens array 70 according to the third embodiment. The third embodiment basically has the same configuration as the second embodiment. Therefore, the description of the same configuration (denoted by the same symbol) is omitted.

  The liquid crystal display device 102 includes a transparent substrate 90 on the outer side of the optical film 10 on the display surface side of the liquid crystal cell 110. A light shielding pattern 75 is formed on the surface of the transparent substrate 90 on the liquid crystal cell 110 side, and a lens array 70 is formed in the opening thereof. Each lens of the microlens 70 is convex in the direction of the liquid crystal cell 110. The transparent substrate 90 is attached to the optical film 10 while maintaining a predetermined interval via a sealing material 91 provided in a frame shape.

  The light shielding pattern 75 and the microlens array 70 can be formed by an offset printing technique as in the second embodiment.

  Note that the sealing material 91 used here contains glass beads or the like called a gap material in order to ensure a thickness equal to or greater than the height of the microlens array 75.

  According to this embodiment, the transparent substrate 90 is provided on the outermost side, and the hemispherical convex microlens array 70 is accommodated therein. Therefore, the liquid crystal display device 102 without unevenness on the display surface side is obtained.

  Note that the liquid crystal display device 102 of this embodiment may not include the light shielding pattern 75 as in the first embodiment.

<Fourth Embodiment>
FIG. 12 is a cross-sectional view of a liquid crystal display device 103 including a microlens array 70 according to the fourth embodiment. The fourth embodiment basically has the same configuration as the third embodiment. Therefore, the description of the same configuration (denoted by the same symbol) is omitted.

  The liquid crystal display device 103 includes a transparent substrate 90 on which a microlens 70 is formed, as in the third embodiment. However, the transparent substrate 90 is attached to the display surface side of the color filter substrate 20 via a sealing material 91, and the optical film 10 is attached to the outer side of the transparent substrate 90.

  In other words, the color on the display surface side of the liquid crystal cell 120 composed of the color filter substrate 20, the liquid crystal layer 40 sealed with the sealing material 30, the TFT substrate 50, and the optical film 60 on the TFT substrate 50 side. A transparent substrate 90 is provided further outside the filter substrate 20. On the surface of the transparent substrate 90 on the liquid crystal cell 110 side, a light shielding pattern 75 and a lens array 70 are formed at the opening. Each lens of the microlens 70 is convex in the direction of the liquid crystal cell 110. The transparent substrate 90 is affixed to the optical film 10 via a sealing material 91 provided in a frame shape. An optical film 10 such as a polarizing plate is attached to the outer side of the transparent substrate 90.

  The light shielding pattern 75 and the microlens array 70 can be formed by an offset printing technique as in the second embodiment and the third embodiment.

  Further, the seal material 91 used here contains glass beads or the like called a gap material in order to ensure a thickness equal to or higher than the height of the lens array, and ensures a desired thickness.

  According to the present embodiment, the hemispherical convex microlens array 70 is accommodated inside the transparent substrate 90. Therefore, the liquid crystal display device 103 has no unevenness on the surface on the display surface side.

  Note that the liquid crystal display device 103 according to the present embodiment may not include the light shielding pattern 75 as in the first embodiment.

  In the above, several embodiments have been described. As described above, a high-precision microlens can be formed by using high-precision offset printing among transfer printing. Specifically, compared to the case of screen printing, a microlens array with fewer bubbles and less shape collapse can be obtained. The transparency of the microlens array in the above embodiment is 80% or more in the visible light wavelength region. Thus, an integral photography autostereoscopic display device with high display performance can be obtained.

1 is a plan view of a liquid crystal display device to which an embodiment of the present invention is applied. A-A 'sectional view of a liquid crystal display. The figure explaining the formation process of a micro lens array. The figure explaining the formation process of a micro lens array. The figure explaining the formation process of a micro lens array. The figure explaining the formation process of a micro lens array. The figure explaining the formation process of a micro lens array. The figure explaining the formation process of a micro lens array. 1 is a plan view of a liquid crystal display device to which an embodiment of the present invention is applied. A-A 'sectional view of a liquid crystal display. A-A 'sectional view of a liquid crystal display. A-A 'sectional view of a liquid crystal display.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... External optical film 20 ... Color filter substrate, 21 ... Common electrode 30 ... Sealing material 40 ... Liquid crystal 50 ... TFT substrate, 51 ... Pixel electrode 60 ... External optical film 70 ... micro lens array 75 ... light shielding pattern 80 ... backlight module 100, 101, 102, 103 ... liquid crystal display device 110, 120 ... liquid crystal cell

Claims (13)

A liquid crystal display device in which liquid crystal is sandwiched between cells surrounded by two opposing substrates,
On the display surface side of the liquid crystal display device, a lens array for stereoscopic viewing arranged to correspond to a plurality of pixels is arranged,
The liquid crystal display device, wherein the lens array is formed by offset printing. A liquid crystal display device in which liquid crystal is sandwiched between cells surrounded by two opposing substrates,
On the display surface side of the liquid crystal display device, a lens array for stereoscopic viewing arranged to correspond to a plurality of pixels is arranged,
Between each lens constituting the lens array, a light shielding pattern is formed,
The liquid crystal display device, wherein the light shielding pattern is formed by offset printing. The liquid crystal display device according to claim 2,
The liquid crystal display device, wherein the lens array is formed by offset printing. The liquid crystal display device according to claim 2,
The liquid crystal display device, wherein the light shielding pattern is formed of a photocurable resin containing carbon black. The liquid crystal display device according to claim 2,
The liquid crystal display device, wherein the light shielding pattern is formed of a thermosetting resin containing carbon black. The liquid crystal display device according to claim 1 or 2,
The liquid crystal display device, wherein the microlens array is made of a photocurable resin. The liquid crystal display device according to claim 1 or 2,
The liquid crystal display device, wherein the microlens array is formed of a thermosetting resin. The liquid crystal display device according to claim 1 or 2,
The liquid crystal display device, wherein the microlens array is formed on a polarizing plate. The liquid crystal display device according to claim 1 or 2,
2. The liquid crystal display device according to claim 1, wherein the microlens array is formed on a transparent substrate attached to a polarizing plate with a predetermined interval, and is convex toward the inside. The liquid crystal display device according to claim 1 or 2,
The microlens array is formed on a transparent substrate adhered to a color filter substrate with a predetermined interval,
A liquid crystal display device, wherein a polarizing plate is attached to the outside of the transparent substrate. The liquid crystal display device according to claim 1 or 2,
The height of the microlens is in a range of 10 to 60 μm. The liquid crystal display device according to claim 1 or 2,
The liquid crystal display device, wherein the microlens has a hemispherical shape. The liquid crystal display device according to claim 1 or 2,
The diameter of the microlens is in the range of 100 to 600 μm.

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