JP2009288637A - Optical compensation plate, liquid crystal device and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical compensation plate used for a liquid crystal device or the like, capable of properly compensating phase difference and adapted to be made small-sized. <P>SOLUTION: The optical compensation plate (200) includes a support substrate (290), a first optical compensation element (210) provided on the support substrate and having a first optical axis having positive uniaxial property and tilted by a prescribed angle to the substrate surface of the support substrate as an optical axis and a second optical compensation element (220) provided to be laid over the first optical compensation element on the support substrate and having a slow axis in the view from a direction along the normal line of the substrate surface of the support substrate. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technical field of an optical compensator used for a liquid crystal device such as a liquid crystal light valve, a liquid crystal device including the same, and an electronic apparatus.

  This type of optical compensator is used, for example, in a liquid crystal device including a liquid crystal panel functioning as a liquid crystal light valve in order to prevent the contrast from being lowered due to the phase difference (or phase shift) of light generated in the liquid crystal layer. .

  With regard to such an optical compensation plate, for example, Patent Document 1 discloses a technique in which an optically anisotropic element as an optical compensation plate is inclined with respect to a vertical alignment type liquid crystal element according to the alignment direction of liquid crystal molecules. It is disclosed.

JP 2006-11298 A

  However, for example, when the optical compensation plate is inclined and disposed as in the technique disclosed in Patent Document 1, it is necessary to secure a space for arranging the optical compensation plate. For this reason, there is a technical problem that it is difficult to reduce the size of the liquid crystal device itself or a projector including the liquid crystal device, and the degree of freedom in layout is hindered.

  Furthermore, since the optical compensator is inclined according to the alignment direction of the liquid crystal molecules, the mechanism for inclining the optical compensator becomes complicated depending on the alignment direction, or additional adjustment is required in the assembly process. There is a technical problem that there is a possibility.

  The present invention has been made in view of, for example, the above-described problems. For example, an optical compensator capable of appropriately compensating for a phase difference and suitable for downsizing, a liquid crystal device including the same, and an electronic apparatus are provided. The issue is to provide.

  In order to solve the above problems, an optical compensation plate of the present invention is provided on a support substrate and the support substrate, has a positive uniaxial property, and has an optical axis at a predetermined angle with respect to the substrate surface of the support substrate. When viewed from a direction along a normal line of the substrate surface of the support substrate, the first optical compensation device having an inclined first optical axis, and provided on the support substrate so as to overlap the first optical compensation device And a second optical compensation element having a slow axis.

  The optical compensator of the present invention includes, for example, a liquid crystal composed of a pair of substrates and liquid crystal molecules sandwiched between the pair of substrates and provided with a pretilt (typically a vertical alignment type liquid crystal, that is, VA (Vertical Alignment type liquid crystal panel) and a pair of polarizing plates arranged so as to sandwich the liquid crystal panel, for example, in a liquid crystal device functioning as a liquid crystal light valve, to compensate for the phase difference of light generated in the liquid crystal Used for.

  According to the optical compensation plate of the present invention, the first and second optical compensation elements are provided on a support substrate made of a transparent substrate such as a glass substrate. The first optical compensation element has a positive uniaxial property, and includes, for example, a positive uniaxial crystal. The first optical axis that is the optical axis (that is, the optical axis) of the first optical compensation element is inclined by a predetermined angle with respect to the substrate surface of the support substrate. The predetermined angle is typically a pretilt angle in a liquid crystal device in which an optical compensator is used (that is, a long axis of liquid crystal molecules provided with a pretilt is in a normal direction of one plane along a pair of substrates. It is predetermined according to the angle formed. For example, the predetermined angle is determined such that the angle formed by the first optical axis with respect to the normal direction of the substrate surface of the support substrate is equal to the pretilt angle. The second optical compensation element is provided on the support substrate so as to overlap the first optical compensation element. That is, the first and second optical compensation elements are provided on the support substrate so as to overlap each other in this order or in the opposite order. The second optical compensation element has a slow axis when viewed from the direction along the normal line of the substrate surface of the support substrate. For example, a positive uniaxial retardation plate (ie, an A plate) It consists of a biaxial plate.

  Therefore, according to the optical compensation plate of the present invention, for example, the optical compensation plate is opposed to the liquid crystal panel between the pair of polarizing plates in the liquid crystal device (that is, on one plane along the pair of substrates). The normal direction and the normal direction of the substrate surface of the support substrate coincide with each other) and the direction in which the major axis of the liquid crystal molecules to which the pretilt is applied is inclined with respect to one plane along the pair of substrates. The optical compensation element is arranged so that the direction in which the first optical axis of the optical compensation element is inclined is different from each other, and is rotated and adjusted around the axis along the normal line of one plane along the pair of substrates. The phase difference generated in the liquid crystal included in the liquid crystal panel can be appropriately compensated. More specifically, for example, during operation of a liquid crystal device that functions as a liquid crystal light valve, a phase difference of light generated by incident light passing through liquid crystal composed of liquid crystal molecules inclined with respect to a pair of substrates is calculated. The optical compensation plate of the present invention can be compensated by the first and second optical compensation elements. In other words, the first and second optical compensation elements can reduce the anisotropy of the overall refractive index of the liquid crystal sandwiched between the pair of substrates and the first and second optical compensation elements. That is, the refractive index ellipsoid showing the anisotropy of the refractive index of the entire liquid crystal and the optical compensator can be made close to a sphere. By performing such compensation, it is possible to prevent the light that has passed through the liquid crystal from entering the output-side polarizing plate in a state of being out of phase. Therefore, for example, in the polarizing plate on the emission side, the possibility of leakage of light that should not be transmitted is reduced, and it is possible to prevent a decrease in contrast and a reduction in viewing angle.

  Furthermore, the optical compensation plate of the present invention can compensate for the phase difference of light generated in the liquid crystal without being inclined with respect to the pair of substrates constituting the liquid crystal panel. Therefore, it can be suitable for downsizing of a liquid crystal device or the like.

  In addition, since the optical compensation plate of the present invention is provided with the first and second optical compensation elements on a single support substrate, the first and second optical compensation elements are assumed to be on separate support substrates. Compared to the case where the optical compensator is configured as two optical compensators, the space for disposing the optical compensator can be narrowed, and the transmittance for transmitting light can be improved.

  The optical compensator of the present invention may be provided on the side where light enters the pair of substrates (in other words, the side where light enters the liquid crystal), or the light is emitted from the pair of substrates. It may be provided on the side.

  The liquid crystal is not limited to the VA type liquid crystal, and a TN (Twisted Nematic) type liquid crystal is set by appropriately setting the relationship between the first optical axis of the first optical compensation element and the slow axis of the second optical compensation element. Even an OCB (Optically Compensated Birefringence) type liquid crystal can be compensated effectively.

  As described above, according to the optical compensation plate of the present invention, the first and second optical compensation elements can appropriately compensate for the phase difference generated in the liquid crystal and can be suitable for miniaturization.

  In one aspect of the optical compensation plate of the present invention, the support substrate and the first and second optical compensation elements are bonded to each other with an adhesive that transmits light.

  According to this aspect, the support substrate and the first and second optical compensation elements are compared so that the first optical axis of the first optical compensation element and the slow axis of the second optical compensation element have a predetermined relationship. Can be attached easily. Therefore, it is possible to reduce the cost due to the failure to arrange the first and second optical compensation elements on the support substrate.

  In another aspect of the optical compensation plate of the present invention, the second optical compensation element has a positive uniaxial property and has a second optical axis along the substrate surface of the support substrate as an optical axis.

  According to this aspect, the second optical compensation element is provided on the support substrate such that the second optical axis of the second optical compensation element is along the substrate surface of the support substrate. Therefore, as described above, the optical compensation plate is rotated and adjusted around the axis along the normal line of one plane in the liquid crystal device, as described above, for example, by the second optical compensation element, the liquid crystal and the first optical compensation element. It is possible to cancel the phase difference of light caused by the above, or to fine-tune the polarization state of light.

  In another aspect of the optical compensation plate of the present invention, the first optical compensation element includes a positive uniaxial crystal and is formed by polishing so that the optical axis is inclined with respect to one surface. It consists of a crystal plate.

  According to this aspect, the first optical compensation element can be configured as a crystal plate having an optical axis inclined with respect to the substrate surface of the support substrate in a relatively easy manner. Here, “one surface” according to the present invention means one main surface in a flat crystal plate having two main surfaces. In the case of using quartz as the positive uniaxial crystal, for example, it is cheaper than the case of using sapphire or the like, and the processing of the crystal plate is easy. Thus, cost reduction can be achieved.

  A crystal plate whose optical axis is inclined with respect to one surface is formed by, for example, cutting a crystal by tilting it at a predetermined angle with respect to the optical axis of the crystal and polishing it to a predetermined thickness. Good. The surface opposite to the one surface is preferably polished so as to be parallel to the one surface.

  In another aspect of the optical compensation plate of the present invention, the first and second optical compensation elements have the first optical axis and the retardation when viewed from a direction along a normal line of the substrate surface of the support substrate. It arrange | positions so that a phase axis may mutually cross.

  According to this aspect, the first and second optical compensation elements have the first optical axis and the second optical compensation element when viewed from the direction along the normal line of the substrate surface of the support substrate. For example, the slow axis of the first optical compensation element and the optical axis of the second optical compensation element form an angle of about 45 degrees. In this case, the transmission axis of the polarizing plate and the tilt direction in which the liquid crystal molecules constituting the liquid crystal tilt (that is, the direction in which the liquid crystal molecules tilt in one plane along the pair of substrates) are, for example, about 45 degrees. It is possible to more appropriately compensate for the phase difference generated in the liquid crystal in the liquid crystal device having the angle.

  In another aspect of the optical compensation plate of the present invention, the optical compensation plate further includes a third optical compensation element having a negative uniaxial property and having a third optical axis along the normal direction of the substrate surface of the support substrate as an optical axis.

  According to this aspect, the third optical compensation element is made of, for example, a negative uniaxial retardation plate (that is, a C plate), and the third optical axis that is the optical axis is a normal line of the substrate surface of the support substrate. It is provided on the support substrate along the direction. Therefore, the phase difference of light generated by passing through the liquid crystal can be more reliably compensated. In other words, the liquid crystal sandwiched between the pair of substrates by the first, second, and third optical compensation elements, and the refractive index anisotropy of the entire first, second, and third optical compensation elements are further increased. It can be made even smaller. That is, the refractive index ellipsoid showing the anisotropy of the refractive index of the entire liquid crystal and the optical compensation plate can be made closer to a sphere. Accordingly, it is possible to more reliably prevent a decrease in contrast and a reduction in viewing angle.

  Note that the order in which the first, second, and third optical compensation elements are provided on the support substrate may be any order.

  In order to solve the above problems, the liquid crystal device of the present invention is disposed opposite to each other and is sandwiched between a pair of substrates each having an alignment film and the pair of substrates, and a pretilt is caused by the alignment film. A liquid crystal composed of a given liquid crystal molecule, a pair of polarizing plates arranged so as to sandwich the pair of substrates, and the optical compensator of the present invention described above (including various aspects thereof), The compensation plate is disposed between the pair of polarizing plates so that the normal direction of one plane along the pair of substrates and the normal direction of the substrate surface of the support substrate coincide with each other and the one plane. The liquid crystal molecules provided with the pretilt are arranged so that the direction in which the major axis is inclined and the direction in which the first optical axis is inclined are different from each other, and the axis along the normal line of the one plane is It is configured to be rotatable as a center.

  According to the liquid crystal device of the present invention, since the optical compensation plate of the present invention described above is provided, the phase difference generated in the liquid crystal can be appropriately compensated. Therefore, a high-quality image with a relatively high contrast can be displayed. Furthermore, it can be suitable for downsizing.

  In one aspect of the liquid crystal device of the present invention, the optical compensator is rotationally adjusted so as to cancel the phase difference of light generated by the liquid crystal.

  According to this aspect, the optical compensator is rotationally adjusted so that the phase difference of the light generated by the liquid crystal is canceled out by, for example, a rotation adjusting means provided outside the liquid crystal device. Therefore, the refractive index anisotropy of the entire liquid crystal and the optical compensation plate can be further reduced.

  In another aspect of the liquid crystal device of the present invention, the optical compensator is configured such that the slow axis of the pair of polarizing plates is in a state where the slow axis is along the transmission axis of one of the pair of polarizing plates. Among them, the rotation is adjusted so as to adjust the polarization state of the light emitted from the polarizing plate disposed on the light incident side with respect to the pair of substrates.

  According to this aspect, first, the optical compensation plate is in a state in which the slow axis of the second optical compensation element is along the transmission axis of the polarizing plate on the incident side or the outgoing side. For example, rotation adjustment is performed by a rotation adjustment unit provided outside the liquid crystal device so as to adjust the polarization state of the light emitted from the incident-side polarizing plate. Therefore, the polarization state of the light is adjusted by the optical compensation plate (particularly, the second optical compensation element), and the light can be incident in a more optimal polarization state with respect to the output-side polarizing plate. Therefore, it is possible to display a higher quality image.

  In another aspect of the liquid crystal device of the present invention, the liquid crystal is a vertical alignment type liquid crystal.

  According to this aspect, the liquid crystal molecules are vertically aligned, and the pretilt imparted to the liquid crystal molecules by both of the alignment films provided on each of the pair of substrates is the same. Therefore, the optical compensator plate is used to detect the phase difference of light caused by the long axis of the liquid crystal molecules provided with the pretilt by the two alignment films being inclined with respect to the normal line of the plane along the pair of substrates. The first and second optical compensation elements can effectively compensate.

  In another aspect of the liquid crystal device of the present invention, the liquid crystal device further includes a microlens array disposed on a light incident side with respect to the pair of substrates, and the optical compensator emits light to the pair of substrates. It is arranged on the side to be.

  According to this aspect, since the optical compensator is disposed on the side from which the light is emitted with respect to the microlens array, the phase difference generated when the light bent by the microlens array passes through the liquid crystal is optically detected. Compensation can be ensured by the compensation plate. In other words, the adverse effect on the phase shift of light by the microlens array can be almost or completely eliminated.

  In order to solve the above problems, a liquid crystal device of the present invention comprises the above-described liquid crystal device of the present invention (including various aspects thereof).

  According to the electronic apparatus of the present invention, since the above-described liquid crystal device of the present invention is provided, the phase difference generated in the light passing through the liquid crystal layer can be compensated, and high contrast can be realized. . As a result, a projection display device, television, mobile phone, electronic notebook, word processor, viewfinder type or monitor direct view type video tape recorder, workstation, video phone, Various electronic devices such as a POS terminal and a touch panel can be realized.

  The operation and other advantages of the present invention will become apparent from the best mode for carrying out the invention described below.

Embodiments of the present invention will be described with reference to the drawings. In the following embodiments, a TFT active matrix driving type liquid crystal device with a built-in driving circuit, which is an example of the liquid crystal device of the present invention, is taken as an example.
<First Embodiment>
First, a liquid crystal panel constituting the liquid crystal device according to the first embodiment will be described with reference to FIGS. The liquid crystal device according to the present embodiment is a liquid crystal device used for a light valve of a projection display device such as a liquid crystal projector. FIG. 1 is a plan view showing the configuration of the liquid crystal panel according to this embodiment, and FIG. 2 is a cross-sectional view taken along the line HH ′ of FIG. In FIG. 1 and FIG. 2, the optical compensator and the polarizing plate, which will be described in detail later, are not disposed, and only the liquid crystal panel is shown.

  1 and 2, in a liquid crystal panel 100 constituting the liquid crystal device according to the present embodiment, a TFT array substrate 10 and an opposing substrate 20 as an example of “a pair of substrates” according to the present invention are arranged to face each other. . A liquid crystal layer 50 is sealed between the TFT array substrate 10 and the counter substrate 20, and the TFT array substrate 10 and the counter substrate 20 are provided with a sealing material 52 provided in a seal region positioned around the image display region 10a. Are bonded to each other.

  In FIG. 1, a light-shielding frame light-shielding film 53 that defines the frame area of the image display region 10a is provided on the counter substrate 20 side in parallel with the inside of the seal region where the sealing material 52 is disposed. A data line driving circuit 101 and an external circuit connection terminal 102 are provided along one side of the TFT array substrate 10 in a region located outside the sealing region in which the sealing material 52 is disposed in the peripheral region. The sampling circuit 7 is provided so as to be covered with the frame light shielding film 53 on the inner side of the seal region along the one side. The scanning line driving circuit 104 is provided so as to be covered with the frame light-shielding film 53 inside the seal region along two sides adjacent to the one side. On the TFT array substrate 10, vertical conduction terminals 106 for connecting the two substrates with the vertical conduction material 107 are arranged in regions facing the four corner portions of the counter substrate 20. Thus, electrical conduction can be established between the TFT array substrate 10 and the counter substrate 20.

  On the TFT array substrate 10, a lead wiring 90 is formed for electrically connecting the external circuit connection terminal 102 to the data line driving circuit 101, the scanning line driving circuit 104, the vertical conduction terminal 106, and the like. .

  In FIG. 2, on the TFT array substrate 10, a laminated structure in which wirings such as pixel switching TFTs (Thin Film Transistors), scanning lines, and data lines are formed. In the image display area 10a, pixel electrodes 9a are provided in a matrix on the upper layer of wiring such as pixel switching TFTs, scanning lines, and data lines. An alignment film 16 is formed on the pixel electrode 9a. On the other hand, a light shielding film 23 is formed on the surface of the counter substrate 20 facing the TFT array substrate 10. The light shielding film 23 is formed of, for example, a light shielding metal film or the like, and is patterned, for example, in a lattice shape in the image display region 10a on the counter substrate 20. On the light shielding film 23, a counter electrode 21 made of a transparent material such as ITO (Indium Tin Oxide) is formed in a solid shape so as to face the plurality of pixel electrodes 9a. An alignment film 22 is formed on the counter electrode 21. The liquid crystal layer 50 includes liquid crystal molecules having negative dielectric anisotropy. Therefore, the liquid crystal device according to this embodiment is a liquid crystal device in which the alignment of liquid crystal molecules is controlled in the vertical alignment (VA) mode. The liquid crystal device according to the present invention is not limited to a liquid crystal device having liquid crystal molecules having a negative dielectric anisotropy, and includes, for example, a liquid crystal in which one or several types of nematic liquid crystals are mixed. It may be a liquid crystal device that takes a predetermined alignment state between the pair of alignment films 16 and 22.

  Although not shown here, a surface of the counter substrate 20 opposite to the side facing the liquid crystal layer 50 (that is, the surface on which incident light is incident) is provided on a microlens array described later with reference to FIG. 400 is provided.

  Although not shown here, in addition to the data line driving circuit 101, the scanning line driving circuit 104, etc., on the TFT array substrate 10, in order to inspect the quality, defects, etc. of the liquid crystal device during manufacturing or at the time of shipment. An inspection circuit, an inspection pattern, or the like may be formed.

  Next, the optical compensation plate provided in the liquid crystal device according to the present embodiment will be described with reference to FIGS.

  First, the arrangement position of the optical compensation plate will be described with reference to FIG. FIG. 3 is a cross-sectional view of the liquid crystal device according to this embodiment, showing the configuration of the liquid crystal device according to this embodiment and the incident direction of incident light. In the following drawings, detailed members of the liquid crystal panel 100 shown in FIGS. 1 and 2 are omitted as appropriate, and only directly related members are shown. 3 shows the TFT array substrate 10 and the counter substrate 20 shown in FIG. 2 upside down for convenience of explanation.

  In FIG. 3, the liquid crystal device according to the present embodiment includes a liquid crystal panel 100, a microlens array 400, an optical compensation plate 200, and polarizing plates 310 and 320. The liquid crystal panel 100, the microlens array 400, and the optical compensation plate 200 are arranged so as to be sandwiched between the polarizing plates 310 and 320.

  The microlens array 400 is a microlens array plate in which microlenses corresponding to the respective pixels of the liquid crystal panel 100 are formed, and is provided between the polarizing plate 310 on the incident side and the liquid crystal panel 100. With the microlens array 400, incident light can be collected in units of pixels, and the substantial aperture ratio of the liquid crystal panel 100 can be improved. That is, the microlens array 400 can improve light use efficiency, brightness, and color purity in the liquid crystal panel 100.

  The optical compensation plate 200 is provided between the output-side polarizing plate 320 and the liquid crystal panel 100, and is configured to be rotatable about an axis along the normal line of the substrate surface of the TFT array substrate 10. As will be described later in detail, the optical compensation plate 200 includes a support substrate 290, a first optical compensation element 210, and a second optical compensation element 220.

  Next, the configuration of the optical compensation plate and the polarizing plate will be described with reference to FIGS. FIG. 4 is a perspective view of the optical compensation plate and the polarizing plate according to this embodiment. FIG. 5 is a conceptual diagram showing a method for forming the first optical compensation element according to the present embodiment. FIG. 6 is a schematic diagram showing the relationship between the slow axis of the first optical compensation element and the optical axis of the second optical compensation element. FIG. 4 conceptually shows the state of liquid crystal molecules in the liquid crystal panel 100 in a state where no voltage is applied, in addition to the optical compensator and the polarizing plate. 4 and 5, for convenience of explanation, the angle α and the angle θ1 are illustrated to be larger than actual.

  In FIG. 4, the liquid crystal molecules 501 in the liquid crystal layer 50 have a predetermined orientation (see FIG. 2) in the plane of the counter substrate 20 (or the TFT array substrate 10) by the alignment films 22 and 16 (see FIG. 2) in a state where no voltage is applied. 4, the liquid crystal tilt direction 20r in the vicinity of the interface of the alignment film 22 (that is, the liquid crystal tilt direction 10r in the vicinity of the interface of the alignment film 16), which is the direction along the X direction, is a predetermined angle from the surface. A pretilt that rises only by a predetermined amount is provided, and the film is oriented while being inclined by a pretilt angle α with respect to the normal of the counter substrate 20 (or the TFT array substrate 10).

  Each of the polarizing plates 310 and 320 is made of, for example, a polarizing film that defines the polarization of light, such as PVA (polyvinyl alcohol), and TAC (triacetyl cellulose) that is disposed on each of both surfaces of the polarizing film. It is a polarizing plate provided with the protective layer. The polarizing plate 310 is provided on the side where light enters the liquid crystal panel 100 so as to face the counter substrate 20, and the polarizing plate 320 is provided on the side where light is emitted from the liquid crystal panel 100. It is provided so as to face the array substrate 10. The polarizing plates 310 and 320 are arranged in crossed Nicols so that the transmission axis 311 of the polarizing plate 310 and the transmission axis 321 of the polarizing plate 320 are orthogonal to each other. Each of the transmission axes 311 and 321 is along a direction shifted by about 45 degrees with respect to the tilt direction 20r of the liquid crystal near the interface of the alignment film 22 (that is, the tilt direction 10r of the liquid crystal near the interface of the alignment film 16). . Since the alignment of the liquid crystal molecules 501 of the liquid crystal layer 50 is controlled in the VA mode as described above, the liquid crystal device according to the present embodiment has the image display region 10a (FIG. 1) in a state where no voltage is applied to the liquid crystal layer 50. Display the image in the normally black mode where black is displayed.

  The optical compensation plate 200 includes a support substrate 290, a first optical compensation element 210, and a second optical compensation element 220. The support substrate 290 is made of a transparent substrate such as a glass substrate. The first optical compensation element 210 and the second optical compensation element 220 are provided on the support substrate 290 in this order so as to overlap each other. The support substrate 290, the first optical compensation element 210, and the second optical compensation element 220 are bonded together with an adhesive that transmits light.

  The first optical compensation element 210 is made of a crystal plate formed of a positive uniaxial crystal such as quartz. The optical axis 211 of the first optical compensation element 210 is inclined by an angle θ1 with respect to the normal line (Z axis in FIG. 4) of the substrate surface (XY plane in FIG. 4) of the support substrate 290. The angle θ1 is set to be almost equal to the pretilt angle α or completely in practice. The first optical compensation element 210 is attached to the support substrate 290 with an adhesive that transmits light.

  As shown in FIG. 5 (a), in the present embodiment, the positive uniaxial crystal 2b is moved by an angle θ2 with respect to the optical axis L (here, the angle θ2 is a difference between 90 degrees and the angle θ1). The first optical compensation element 210 as shown in FIG. 5B is formed by cutting along the inclined cutting lines q1 and q2 and polishing to have a predetermined thickness d1. According to such a forming method, for example, when the angle θ2 is set to 85 degrees, the first optical compensation element 210 having an angle θ1 of 5 degrees (that is, an angle almost equal to the pretilt angle α) can be easily formed. . As the polishing, for example, various polishing techniques such as CMP (Chemical Mechanical Polishing) can be applied.

  In FIG. 4 again, the second optical compensation element 220 is composed of a positive uniaxial retardation plate (ie, an A plate). The second optical compensation element 220 is affixed to the first optical compensation element 220 with an adhesive that transmits light.

  Here, as shown in FIG. 6, the first optical compensation element 210 and the second optical compensation element 220 are the first optical compensation element 210 when viewed from the direction along the normal line of the substrate surface of the support substrate 290. The slow axis 213 (or the optical axis 211) and the optical axis 221 of the second optical compensation element 220 are arranged so as to intersect each other at an angle β. The angle β is approximately 45 degrees between each of the transmission axes 311 and 321 and the tilt direction 20r of the liquid crystal near the interface of the alignment film 22 (that is, the tilt direction 10r of the liquid crystal near the interface of the alignment film 16) ( Corresponding to (see FIG. 4), an angle of about 45 degrees is set.

  In FIG. 4 again, the optical compensator 200 configured as described above has a normal direction (Z axis in FIG. 4) along the TFT array substrate 10 of the liquid crystal panel 100 and the substrate surface of the support substrate 290. Arranged so that the normal direction matches. Further, at this time, the optical compensation substrate 200 is liquid crystal in a direction in which the optical axis 211 of the first optical compensation element 210 is inclined with respect to a plane along the TFT array substrate 10 (in other words, an XY plane in FIG. 4). The direction in which the optical axis 221 of the second optical compensation element 220 extends and the polarizing plate 320 are different from each other in the direction in which the long axis of the molecule 501 is inclined and from the normal direction of the plane along the TFT array substrate 10. It arrange | positions so that the direction where the transmission axis 321 of this may extend may correspond. Therefore, the optical compensation plate 200 has the optical axis 211 in the normal line (that is, the Z axis) of the TFT array substrate 10 when viewed in one plane orthogonal to the TFT array substrate 10 along the tilt direction 10r. In contrast, the liquid crystal molecules 501 are arranged so as to be inclined by an angle θ1 in a direction different from the direction in which the major axis of the liquid crystal molecules 501 is inclined. Therefore, the assumed refractive index ellipsoid 212 of the first optical compensation element 210 is also inclined by an angle θ1 with respect to the normal line of the TFT array substrate 10 in a direction different from the direction in which the major axis of the liquid crystal molecules 501 is inclined.

  Further, the optical compensation plate 200 is configured to be rotatable about an axis along the normal direction (that is, the Z direction) of the TFT array substrate 10. In addition, particularly in the present embodiment, the optical compensation plate 200 is rotationally adjusted so as to cancel the phase difference of the light generated by the liquid crystal layer 50. The optical compensation plate 200 also has a function of finely adjusting the polarization state of light. More specifically, as described above, the optical compensation plate 200 includes the direction in which the optical axis 221 of the second optical compensation element 220 extends and the transmission of the polarizing plate 320 when viewed from the normal direction of the plane along the TFT array substrate 10. After being arranged so that the direction in which the axis 321 extends coincides, the phase difference of the light generated by the liquid crystal layer 50 is canceled around the axis along the normal direction (that is, the Z direction) of the TFT array substrate 10. The rotation has been adjusted. In other words, the liquid crystal layer 50 is rotated from the position where the optical compensator 200 is arranged as described above by an angle of, for example, about 1 to 10 degrees around the axis along the normal direction of the TFT array substrate 10. The optical compensator 200 can compensate for the phase difference of light caused by the above.

  Here, the first optical compensation element 210 is at an angle substantially equal to the pretilt angle α, for example, about 5 with respect to the normal line of the plane along the TFT array substrate 10 (Z axis in FIG. 4). Since the optical axis 211 is inclined by (degrees), the change due to rotation of the effect of compensating the phase difference is small as compared with the second optical compensation element 220 having the optical axis 221 along the TFT array substrate 10. Therefore, the effect of compensating for the phase difference due to the second optical compensation element 220 can be enhanced without substantially changing the effect of compensating for the phase difference due to the first optical compensation element 210 by the rotation adjustment described above. The first optical compensation element 210 has a smaller change due to rotation of the effect of compensating for the phase difference than the second optical compensation element 220. Therefore, in the manufacturing process of the optical compensation plate 200, the first optical compensation element 210 The shift in the angle β (see FIG. 6) when the 210 and the second optical compensation element 220 are bonded together hardly or practically reduces the effect of compensating for the phase difference by the optical compensation plate 200.

  Next, the operation of the liquid crystal device according to this embodiment configured as described above will be described with reference to FIG. 7 in addition to FIG. 3 and FIG. FIG. 7 is a conceptual diagram conceptually showing an assumed refractive index ellipsoid obtained by synthesizing the assumed refractive index ellipsoid of the liquid crystal layer and the assumed refractive index ellipsoid of the first optical compensation element.

  In FIG. 3, when the liquid crystal device according to this embodiment operates, incident light first enters the polarizing plate 310 on the incident side. In the polarizing plate 310, only light that vibrates in the direction along the transmission axis 311 can pass. That is, incident light becomes linearly polarized light by passing through the polarizing plate 310. Incident light that has passed through the polarizing plate 310 passes through the microlens array 400 and the counter substrate 20 and enters the liquid crystal layer 50.

  In FIG. 4, the liquid crystal molecules 501 in the liquid crystal layer 50 are in one direction (that is, X direction) along the tilt direction 10 r with respect to the normal direction (that is, the Z direction) of the TFT array substrate 10 when no voltage is applied. It is oriented with a pretilt angle α inclined in the positive direction of the axis. Therefore, as shown in FIG. 7, the assumed refractive index ellipsoid 501e indicating the anisotropy of the refractive index of the entire liquid crystal layer 50 is also tilted in the tilt direction 10r with respect to the normal direction (that is, the Z direction) of the TFT array substrate 10. Is tilted by a pretilt angle α in one direction along the axis (that is, the positive direction of the X axis). Therefore, if no measures are taken, the light incident on the liquid crystal layer 50 causes a phase difference due to the assumed refractive index ellipsoid 501e of the liquid crystal layer 50 being inclined by the pretilt angle α. The light that has passed through the liquid crystal layer 50 enters the output-side polarizing plate 320 in a state of being out of phase. In addition, there is a possibility that a phase difference is caused when incident light passes through the microlens array 400 and the polarizing plates 310 and 320. For this reason, there is a possibility that light that should not pass through the polarizing plate 320 on the emission side may leak.

  However, in FIG. 4 and FIG. 7, the liquid crystal device according to the present embodiment includes the optical compensator 200, and thus compensates for the phase difference of the light generated when the incident light passes through the liquid crystal layer 50. Can do. In other words, the optical compensation plate 200 can reduce the refractive index anisotropy of the entire liquid crystal layer 50 and the optical compensation plate 200. That is, first, with respect to the liquid crystal layer 50 having the assumed refractive index ellipsoid 501e inclined by the pretilt angle α, the first liquid crystal layer 50 having the assumed refractive index ellipsoid 212 inclined to the opposite side of the assumed refractive index ellipsoid 501e by the angle θ1. By arranging the one optical compensation element 210, the assumed refractive index ellipsoid 292 of the entire liquid crystal layer 50 and the first optical compensation element 210 is approximated to a biaxial refractive index ellipsoid. Therefore, the first optical compensation element 210 can compensate for the phase difference caused by the assumed refractive index ellipsoid 501e of the liquid crystal layer 50 being inclined by the pretilt angle α. Further, since the optical compensation plate 200 is rotationally adjusted so as to cancel the phase difference of light generated by the liquid crystal layer 50, the entire refraction of the liquid crystal layer 50, the first optical compensation element 210, and the second optical compensation element 220 is adjusted. The rate anisotropy can be reduced. In other words, the optical compensator 200 is rotated and adjusted so that, for example, little or no light is emitted from the output-side polarizing plate 320 in a state where no voltage is applied, so that the phase difference of the light generated by the liquid crystal layer 50 is achieved. Can be reliably compensated.

  By performing such compensation, it is possible to prevent the light that has passed through the liquid crystal layer 50 from entering the output-side polarizing plate 320 in a state of being out of phase. Furthermore, since the optical compensation plate 200 also has a function of adjusting the polarization state of light, light can be incident on the output-side polarizing plate 320 in a more optimal polarization state. Therefore, for example, in the polarizing plate 320 on the emission side, the possibility of leakage of light that should not be transmitted is reduced, and it is possible to prevent a decrease in contrast and a reduction in viewing angle.

  Furthermore, the optical compensation plate 200 can compensate for the phase difference of light generated in the liquid crystal layer 50 without being inclined with respect to the TFT array substrate 10 and the counter substrate 20. Therefore, it can be suitable for downsizing the liquid crystal device and the like.

  It is desirable that the retardation (Δn · d) of the first optical compensation element 210 in the Z direction is almost or completely equal to the retardation of the liquid crystal layer 50 in the Z direction. In this case, the effect of compensating for the phase difference generated in the liquid crystal layer 50 can be further enhanced. However, even if the retardation of the first optical compensation element 210 in the Z direction is almost or completely equal to the retardation of the liquid crystal layer 50 in the Z direction, the retardation of the first optical compensation element 210 in the Z direction and the Z of the liquid crystal layer 50 are the same. The effect of compensating for the phase difference generated in the liquid crystal layer 50 can be increased correspondingly according to the difference from the retardation with respect to the direction. That is, for example, when the retardation of the liquid crystal layer 50 in the Z direction is 450 nm, the retardation of the first optical compensation element 210 is desirably 450 nm, but if the retardation is within a range of 300 nm to 500 nm, for example, The effect of compensating for the phase difference generated in the layer 50 can be reliably increased. The retardation of the second optical compensation element 220 with respect to the Z direction is preferably in the range of 10 nm to 100 nm, for example. In this case, the effect of compensating for the phase difference of the light generated by the liquid crystal layer 50 can be reliably obtained by the optical compensation plate 200 whose rotation has been adjusted.

  In addition, in this embodiment, in particular, the optical compensation plate 200 is provided on the side from which light is emitted with respect to the liquid crystal panel 100. That is, the optical compensation base plate 200 is arranged on the side from which light is emitted with respect to the microlens array 400. Therefore, the optical compensator 200 can reliably compensate for the phase difference generated when the light bent by the microlens array 400 passes through the liquid crystal layer 50. In other words, the adverse effect on the phase difference of light by the microlens array 400 can be almost or completely eliminated. The optical compensation plate 200 may be provided on the side where light enters the liquid crystal panel 100 (in other words, the side where light enters the liquid crystal layer 50). Also in this case, an effect of compensating for the phase difference of light can be obtained.

As described above, according to the liquid crystal device according to the present embodiment, the optical compensation plate 200 can compensate for the phase difference generated in the liquid crystal layer 50. Therefore, a high-definition image having a relatively high contrast can be displayed and can be suitable for downsizing.
Second Embodiment
A liquid crystal device according to a second embodiment will be described with reference to FIG. FIG. 8 is a perspective view having the same concept as in FIG. 4 in the second embodiment. In FIG. 8, the same components as those in the first embodiment shown in FIGS. 1 to 7 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  In FIG. 8, the liquid crystal device according to the second embodiment is different from the liquid crystal device according to the first embodiment described above in that an optical compensation plate 200b is provided instead of the optical compensation plate 200 according to the first embodiment described above. The other points are configured in substantially the same manner as the liquid crystal device according to the first embodiment described above.

  The optical compensation plate 200b differs from the optical compensation plate 200 according to the first embodiment described above in that it further includes a third optical compensation element 230 between the first optical compensation element 210 and the second optical compensation element 220. About the point, it is comprised substantially the same as the optical compensation board 200 which concerns on 1st Embodiment mentioned above.

  As shown in FIG. 8, the optical compensation plate 200b includes a support substrate 290, a first optical compensation element 210, a second optical compensation element 220, and a third optical compensation element 230. The first optical compensation element 210, the third optical compensation element 230, and the second optical compensation element 220 are provided on the support substrate 290 so as to overlap each other in this order. The support substrate 290, the first optical compensation element 210, the second optical compensation element 220, and the third optical compensation element 230 are bonded together with an adhesive that transmits light.

  The third optical compensation element 230 is a negative uniaxial retardation plate (that is, a C plate). The optical axis 231 of the third optical compensation element 230 is along the normal direction (Z direction in FIG. 4) of the substrate surface of the support substrate 290. Therefore, the assumed refractive index ellipsoid 232 is also along the normal direction.

  When the optical compensation plate 200b includes the third optical compensation element 230 configured as described above, the phase difference of light generated by passing through the liquid crystal layer 50 can be more reliably compensated. In other words, the liquid crystal layer 50, the first optical compensation element 210, the second optical compensation element 220, and the first optical compensation element 210, the second optical compensation element 220, and the third optical compensation element 230 included in the optical compensation plate 200b. The anisotropy of the entire refractive index of the three optical compensation elements 230 can be further reduced. That is, the refractive index ellipsoid showing the anisotropy of the entire refractive index of the liquid crystal layer 50 and the optical compensation plate 200 can be made closer to a sphere. Accordingly, it is possible to more reliably prevent a decrease in contrast and a reduction in viewing angle.

Note that the order in which the first optical compensation element 210, the second optical compensation element 220, and the third optical compensation element 230 are provided on the support substrate 290 may be different from that in the present embodiment. Even in such a case, the phase difference of light generated by passing through the liquid crystal layer 50 can be reliably compensated.
<Electronic equipment>
Next, an example of an electronic device using the liquid crystal device described above will be described with reference to FIGS. The electronic apparatus according to the present embodiment is a projector that uses the liquid crystal device described above as a light valve. FIG. 9 is a plan view showing a configuration example of the projector.

  As shown in FIG. 9, a projector 1100 includes a lamp unit 1102 made of a white light source such as a halogen lamp. The projection light emitted from the lamp unit 1102 is separated into three primary colors of RGB by four mirrors 1106 and two dichroic mirrors 1108 arranged in the light guide 1104, and serves as a light valve corresponding to each primary color. The light enters the liquid crystal panels 1110R, 1110B, and 1110G.

  The configurations of the liquid crystal panels 1110R, 1110B, and 1110G have the same configuration as that of the above-described liquid crystal device, and are driven by R, G, and B primary color signals supplied from the image signal processing circuit, respectively. The light modulated by these liquid crystal panels enters the dichroic prism 1112 from three directions. In this dichroic prism 1112, R and B light is refracted at 90 degrees, while G light travels straight. Accordingly, as a result of the synthesis of the images of the respective colors, a color image is projected onto the screen or the like via the projection lens 1114.

  Here, paying attention to the display images by the liquid crystal panels 1110R, 1110B, and 1110G, the display images by the liquid crystal panels 1110R and 1110B need to be horizontally reversed with respect to the display images by the liquid crystal panel 1110G.

  Since light corresponding to the primary colors R, G, and B is incident on the liquid crystal panels 1110R, 1110B, and 1110G by the dichroic mirror 1108, it is not necessary to provide a color filter.

  Since such a projector includes the above-described liquid crystal device, the phase difference generated in the light passing through the liquid crystal layer is compensated, a high-contrast image can be displayed, and the size can be further reduced.

  In addition to the electronic device described with reference to FIG. 9, a mobile personal computer, a mobile phone, a liquid crystal television, a viewfinder type or a monitor direct view type video tape recorder, a car navigation device, a pager, and an electronic notebook , Calculators, word processors, workstations, videophones, POS terminals, devices with touch panels, and the like. Needless to say, the present invention can be applied to these various electronic devices.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and an optical compensator with such a change. Liquid crystal devices and electronic devices are also included in the technical scope of the present invention.

It is a top view which shows the structure of the liquid crystal panel which concerns on 1st Embodiment. It is the HH 'sectional view taken on the line of FIG. 1 is a cross-sectional view of a liquid crystal device according to a first embodiment. It is a perspective view of the optical compensator and polarizing plate concerning a 1st embodiment. It is a conceptual diagram which shows the formation method of the 1st optical compensation element which concerns on 1st Embodiment. It is a schematic diagram which shows the relationship between the slow axis of a 1st optical compensation element, and the optical axis of a 2nd optical compensation element. It is a conceptual diagram which shows notionally the assumed refractive index ellipsoid by which the assumed refractive index ellipsoid of a liquid crystal layer and the assumed refractive index ellipsoid of a 1st optical compensation element are synthesize | combined. It is a perspective view of the same meaning as FIG. 4 in 2nd Embodiment. It is a top view which shows the structure of the projector which is an example of the electronic device of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... TFT array substrate, 10r ... Tilt direction, 16 ... Orientation film, 20 ... Opposite substrate, 20r ... Tilt direction, 22 ... Orientation film, 50 ... Liquid crystal layer, 100 ... Liquid crystal panel, 200, 200b ... Optical compensator, 210 ... 1st optical compensation element, 220 ... 2nd optical compensation element, 230 ... 3rd optical compensation element, 211, 221, 231 ... Optical axis, 212, 222, 232 ... Assumed refractive index ellipsoid, 213 ... Slow axis, 290 ... support substrate, 310, 320 ... polarizing plate, 311, 321 ... transmission axis, 400 ... microlens array

Claims (12)

A support substrate;
A first optical compensation element provided on the support substrate, having a positive uniaxial property and having, as an optical axis, a first optical axis inclined by a predetermined angle with respect to a substrate surface of the support substrate;
A second optical compensation element provided on the support substrate so as to overlap the first optical compensation element and having a slow axis when viewed from a direction along a normal line of the substrate surface of the support substrate. An optical compensator characterized by.   The optical compensation plate according to claim 1, wherein the support substrate and the first and second optical compensation elements are bonded to each other with an adhesive that transmits light.   The optical compensation plate according to claim 1, wherein the second optical compensation element has a positive uniaxial property and has a second optical axis along the substrate surface of the support substrate as an optical axis. .   2. The first optical compensation element includes a crystal plate that includes a positive uniaxial crystal and is polished so that an optical axis is inclined with respect to one surface. 4. The optical compensation plate according to any one of items 1 to 3.   The first and second optical compensation elements are arranged such that the first optical axis and the slow axis intersect each other when viewed from the direction along the normal line of the substrate surface of the support substrate. The optical compensator according to any one of claims 1 to 4, wherein   6. The third optical compensation element according to claim 1, further comprising a third optical compensation element having a negative uniaxial property and having, as an optical axis, a third optical axis along a normal direction of a substrate surface of the support substrate. The optical compensator according to one item. A pair of substrates disposed opposite to each other and each having an alignment film;
A liquid crystal composed of liquid crystal molecules sandwiched between the pair of substrates and provided with a pretilt by the alignment film;
A pair of polarizing plates arranged to sandwich the pair of substrates;
An optical compensator according to any one of claims 1 to 6,
The optical compensator is arranged so that a normal direction of one plane along the pair of substrates and a normal direction of a substrate surface of the support substrate coincide with each other between the pair of polarizing plates. On the other hand, the direction in which the major axis of the liquid crystal molecules provided with the pretilt is inclined and the direction in which the first optical axis is inclined are different from each other and along the normal line of the one plane. A liquid crystal device configured to be rotatable about an axis.   The liquid crystal device according to claim 7, wherein the optical compensator is rotationally adjusted so as to cancel a phase difference of light generated by the liquid crystal.   The optical compensator is configured such that light is incident on the pair of substrates of the pair of polarizing plates from a state where the slow axis is along the transmission axis of one of the pair of polarizing plates. 9. The liquid crystal device according to claim 7, wherein the liquid crystal device is rotationally adjusted so as to adjust a polarization state of light emitted from a polarizing plate disposed on the side to be operated.   The liquid crystal device according to claim 7, wherein the liquid crystal is a vertical alignment type liquid crystal. A microlens array disposed on the light incident side of the pair of substrates;
The liquid crystal device according to any one of claims 7 to 10, wherein the optical compensation plate is disposed on a side from which light is emitted with respect to the pair of substrates.   An electronic apparatus comprising the liquid crystal device according to any one of claims 7 to 11.

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