JP5262388B2 - Liquid crystal device, projector, and optical compensation method for liquid crystal device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain a high contrast of display in a liquid crystal display. <P>SOLUTION: This projector includes a light source, a liquid crystal panel 15c with a liquid crystal comprising a pretilted liquid crystal molecule 51 sandwiched between a pair of substrates having respectively oriented films, for modulating the light, a pair of polarizing plates 15b, 15d, the first phase difference plate 15a having the first substrate 1501a, a vertically vapor-deposited film 1501c vertically vapor-deposited on the first substrate in order to direct a uniaxial optical axis of a uniaxial refractive index anisotropic medium along a thickness direction, and the first vapor deposition film 1503a vapor-deposited obliquely on the vertically vapor-deposited film, in order to incline the first optical axis of the first refractive index anisotropic medium along the first direction of negating a characteristic change of light due to pretilting, and the second phase difference plate 15e arranged between the pair of polarizing plates, and having the second substrate 1501e and the second vapor deposition film 1503e vapor-deposited obliquely on the second substrate, in order to incline the second optical axis of the second refractive index anisotropic medium along the second direction, different from the first direction, of negating a characteristic change of light due to the pretilting. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a liquid crystal device including a polarizing plate and a retardation plate, a projector including the liquid crystal device, an optical compensation method for the liquid crystal device, and a technical field of a retardation plate used in the liquid crystal device.

  As this type of liquid crystal device, a type of liquid crystal device that is driven in a “VA (Vertical Alignment) mode” has been proposed. Here, as a technique for improving the contrast, a technique in which a retardation plate is arranged to be inclined with respect to a liquid crystal light valve has been proposed (see Patent Document 1 below).

JP 2006-11298 A

  However, when the phase difference plate is inclined and disposed as in the technique disclosed in Patent Document 1, it is necessary to incline the phase difference plate according to the alignment direction of the liquid crystal molecules. In this case, since the space for inclining the phase difference plate is limited in the projector, for example, from the viewpoint of the cooling effect due to air circulation, it may be difficult to increase the contrast. There are some problems. Or the mechanism which inclines this phase difference plate will become complicated, and the adjustment which inclines a phase difference plate will become technically difficult in an assembly process.

  The present invention has been made in view of the above-described problems, for example, and a liquid crystal device capable of displaying a high-contrast image with a relatively simple configuration, a projector including the liquid crystal device, and optical compensation of the liquid crystal device It is an object to provide a method.

(Liquid crystal device)
In the liquid crystal device of one embodiment of the present invention, vertical alignment liquid crystal including liquid crystal molecules imparted with a pretilt by the alignment film is sandwiched between a pair of substrates each having an alignment film to modulate light. A liquid crystal panel, a pair of polarizing plates arranged between the liquid crystal panels, and a pair of polarizing plates, (ia) a first substrate, (ii-a) uniaxial refractive index anisotropy A vertically deposited film vertically deposited on the first substrate so that the uniaxial optical axis of the uniaxial refractive index anisotropic medium having a thickness is along the thickness direction, and (iii-a) anisotropic first refractive index The first optical axis of the first refractive index anisotropic medium is obliquely deposited on the vertical deposition film so that the first optical axis of the first refractive index anisotropic medium is inclined in a first direction that cancels the characteristic change of the light due to the pretilt. A first retardation plate having a vapor deposition film and the pair of polarizing plates; (ib) a second substrate; and (ii-b) The second optical axis of the second substrate has two refractive index anisotropy and the second optical axis of the second refractive index anisotropic medium cancels the characteristic change of the light and is inclined in a second direction different from the first direction. A second retardation plate having a second deposited film obliquely deposited thereon, the first retardation plate being rotatable about the normal line of the substrate of the liquid crystal panel, and the second retardation plate The retardation film can be rotated about the normal line independently of the first retardation film.
In the first liquid crystal device according to the present invention, a vertical alignment type liquid crystal composed of liquid crystal molecules provided with a pretilt by the alignment film is sandwiched between a pair of substrates each having an alignment film. A liquid crystal panel that modulates the liquid crystal, a pair of polarizing plates disposed between the liquid crystal panels, and a pair of polarizing plates, (ia) a first substrate, (ii-a) a uniaxial refractive index A vertically deposited film vertically deposited on the first substrate so that the uniaxial optical axis having anisotropy and the uniaxial refractive index anisotropy is along the thickness direction; and (iii-a) first refraction The first optical axis of the first refractive index anisotropy is obliquely deposited on the vertical deposition film so that the first optical axis of the first refractive index anisotropy is inclined in a first direction that cancels the change in the light characteristics due to the pretilt. A first retardation plate (15a) having a first vapor deposition film and a pair of polarizing plates; (ib) a second substrate And (ii-b) having a second refractive index anisotropy so that the second optical axis of the second refractive index anisotropy cancels the characteristic change and tilts in a second direction different from the first direction. A second retardation plate (15e) having a second deposited film obliquely deposited on the second substrate.

  According to the first liquid crystal device of the present invention, for example, light emitted from the light source is color-separated into red light, green light, and blue light by a color separation optical system such as a reflection mirror and a dichroic mirror. The liquid crystal panel is used as a light valve that modulates red light, green light, and blue light, for example. In the liquid crystal panel, for example, the alignment state of liquid crystal molecules of each pixel is regulated according to a data signal (or image signal), and an image corresponding to the data signal is displayed in the display area. An image displayed by each liquid crystal panel is synthesized by a color synthesis optical system such as a dichroic prism, and projected onto a projection surface such as a screen as a projection image via a projection lens.

  A liquid crystal panel has a liquid crystal sandwiched between a pair of substrates. The liquid crystal is a vertical alignment type liquid crystal, that is, a VA (Vertical Alignment) type liquid crystal. Each of the pair of substrates is provided with an alignment film, and the alignment film imparts a pretilt in which liquid crystal molecules constituting the liquid crystal rise in a certain direction by a certain angle. Since the liquid crystal is VA type, the liquid crystal molecules are oriented with a pretilt angle in a fixed direction with respect to the normal of the substrate surfaces of the pair of substrates. The liquid crystal molecules maintain a pretilt when a voltage is not applied to the liquid crystal panel, and are inclined so as to approach the plane direction of the substrate of the liquid crystal panel when a voltage is applied to the liquid crystal panel. Thereby, a normally black liquid crystal or a normally white liquid crystal can be easily realized. The major axis of the liquid crystal molecules provided with the pretilt and one side of the pair of substrates may typically form an angle of 45 degrees when viewed from the normal direction of the pair of substrates. The liquid crystal panel is disposed so as to be sandwiched between a pair of polarizing plates.

  The vertical vapor deposition film constituting the first retardation plate retains the uniaxial refractive index anisotropy and on the first substrate so that the uniaxial optical axis of the uniaxial refractive index anisotropy is along the thickness direction. Is vertically deposited. In addition, the first vapor deposition film constituting the first retardation plate retains the first refractive index anisotropy, and the first optical axis of the first refractive index anisotropy cancels the change in light characteristics due to the pretilt. It is obliquely deposited on the vertically deposited film so as to be inclined. Here, “light characteristic change” according to the present invention is not only a change in light phase difference but also a change in light traveling direction, a change in polarization state, a basic characteristic parameter of light such as frequency, etc. Means that at least one changes. In addition, the “direction to cancel” according to the present invention means a direction that can ideally and sufficiently cancel, but means a direction including such an ideal direction as a component. In other words, the optical axis having the maximum refractive index of the first refractive index anisotropy when viewed planarly from the direction with the highest canceling ability, typically from the normal direction of the first substrate, is the pretilt. Means the direction intersecting with the major axis direction of the liquid crystal molecules to which is given. Typically, it is preferable that the first vapor deposition film or the vertical vapor deposition film of the first retardation plate includes an inorganic material. Thereby, it is possible to effectively prevent the first retardation plate from being deteriorated due to light irradiation and the accompanying temperature rise, and it is possible to configure a liquid crystal device excellent in reliability.

  Typically, the first optical axis of the first refractive index anisotropic medium constituting the first retardation plate intersects the major axis direction of the liquid crystal molecules to which the pretilt is given as viewed from the normal direction of the first substrate. The first refractive index anisotropic medium is obliquely vapor-deposited on the first substrate as the first vapor deposition film so as to be along the first predetermined direction. Here, the predetermined direction means a direction in which the first optical axis of the refractive index anisotropic medium in which the first optical axis of the first refractive index anisotropic medium intersects with the major axis direction of the liquid crystal molecules. Specifically, in the first predetermined direction, which is the direction in which the first optical axis of the first refractive index anisotropic medium extends, the level of the optical characteristics of the liquid crystal device such as the contrast and the viewing angle is, for example, the maximum. Each value can be specified specifically by experiment, theoretical, empirical, simulation, or the like with reference to the major axis direction of the liquid crystal molecules so that a desired value such as a value is obtained.

  In addition, typically, the first refractive index anisotropy is such that the first optical axis of the first refractive index anisotropic medium of the first retardation plate described above intersects the first substrate at a first predetermined angle. The medium is obliquely deposited on the first substrate as the first deposited film. Here, the first predetermined angle means an angle at which the optical axis of the first refractive index anisotropic medium and the first substrate intersect. This first predetermined angle can be rephrased as a value obtained by subtracting the angle between the normal line of the first substrate and the optical axis corresponding to the main refractive index of the first refractive index anisotropic medium from 90 degrees. Alternatively, the first predetermined angle can be restated as an angle between the first optical axis corresponding to the main refractive index of the first refractive index anisotropic medium and the first predetermined direction described above. Specifically, the first predetermined angle, which is the angle at which the first optical axis of the first refractive index anisotropic medium and the first substrate intersect, is an optical characteristic of the liquid crystal device such as contrast and viewing angle. For example, the level can be specifically defined by experiment, theoretical, empirical, simulation, or the like so that the level becomes a desired value such as a maximum value.

  That is, the major axis of the refractive index ellipsoid formed by the liquid crystal molecules and the major axis of the refractive index ellipsoid formed by the first vapor deposition film constituting the first retardation plate constitute the first retardation plate. Since the major axis of the refractive index ellipsoid formed by the vertical vapor deposition film intersects, the refractive index ellipsoid formed by the three of the liquid crystal molecules, the vertical vapor deposition film, and the first vapor deposition film is three-dimensionally shown as a refractive index sphere. Can approach.

  On the other hand, the second retardation plate holds (ib) the second substrate and (ii-b) the second refractive index anisotropy, and the second optical axis of the second refractive index anisotropy is the light of the pretilt. The second deposited film is obliquely deposited on the second substrate so as to cancel the characteristic change and to incline in a second direction different from the first direction.

  Typically, the second optical axis of the second refractive index anisotropic medium constituting the second retardation plate intersects the major axis direction of the liquid crystal molecules to which the pretilt is given as viewed from the normal direction of the second substrate. The second refractive index anisotropic medium is obliquely vapor-deposited on the second substrate as the second vapor deposition film so as to be along the second predetermined direction. Here, the second predetermined direction means a direction in which the second optical axis of the refractive index anisotropic medium extends where the optical axis of the second refractive index anisotropic medium and the major axis direction of the liquid crystal molecules intersect. Specifically, in the second predetermined direction, which is the direction in which the second optical axis of the second refractive index anisotropic medium extends, the level of the optical characteristics of the liquid crystal device such as the contrast and the viewing angle is, for example, the maximum. Each value can be specified specifically by experiment, theoretical, empirical, simulation, or the like with reference to the major axis direction of the liquid crystal molecules so that a desired value such as a value is obtained.

  In addition, typically, the second refractive index anisotropy is such that the second optical axis of the second refractive index anisotropic medium of the second retardation plate described above intersects the second substrate at a second predetermined angle. The medium is obliquely deposited on the second substrate as the second deposited film. Here, the second predetermined angle means an angle at which the second optical axis of the second refractive index anisotropic medium and the second substrate intersect. This second predetermined angle can be rephrased as a value obtained by subtracting the angle between the normal line of the second substrate and the second optical axis corresponding to the main refractive index of the second refractive index anisotropic medium from 90 degrees. it can. Alternatively, this second predetermined angle can be rephrased as the angle between the second optical axis corresponding to the main refractive index of the second refractive index anisotropic medium and the second predetermined direction described above. Specifically, the second predetermined angle, which is the angle at which the second optical axis of the second refractive index anisotropic medium and the second substrate intersect, is an optical characteristic of the liquid crystal device such as contrast and viewing angle. For example, the level can be specifically defined by experiment, theoretical, empirical, simulation, or the like so that the level becomes a desired value such as a maximum value.

  As a result, the first optical axis (typically nx ′ (however, nx ′> ny ′> nz ′)) of the first retardation plate intersects the major axis direction of the liquid crystal molecules inclined by the pretilt angle. Since it is along the predetermined direction, the first optical axis of the first retardation plate compensates for the optical anisotropy of the liquid crystal molecules toward optical isotropy in the planar direction of the first substrate. In addition, since the first optical axis (typically nx ′) of the first retardation plate intersects the first substrate at a first predetermined angle, the first retardation plate of the first retardation plate in the vertical plane direction of the first substrate. The first optical axis compensates for the optical anisotropy of the liquid crystal molecules so as to be toward optical isotropy. That is, since the major axis of the first refractive index ellipsoid formed by the liquid crystal molecules intersects with the major axis of the first refractive index ellipsoid formed by the first retardation plate, the liquid crystal molecules and the first retardation plate are intersected. The first refractive index ellipsoid formed by the above can be approximated three-dimensionally to the refractive index sphere.

  In addition, the second optical axis of the second retardation plate (typically nx ″ (however, nx ″> ny ″> nz ″)) is the major axis direction of the liquid crystal molecules inclined by the pretilt angle. In the plane direction of the second substrate, the second optical axis of the second retardation plate compensates for the optical anisotropy of the liquid crystal molecules toward optical isotropy. To do. In addition, since the second optical axis (typically nx ″) of the second retardation plate intersects the second substrate at a second predetermined angle, the second retardation plate in the vertical plane direction of the second substrate. The second optical axis compensates for the optical anisotropy of the liquid crystal molecules to be optically isotropic. That is, since the major axis of the second refractive index ellipsoid formed by the liquid crystal molecules intersects with the major axis of the second refractive index ellipsoid formed by the second retardation plate, the liquid crystal molecules and the second retardation plate are intersected. The second refractive index ellipsoid formed by the above can be approximated three-dimensionally to the refractive index sphere.

  Therefore, the phase difference (in other words, birefringence effect) generated in the liquid crystal by the first and second retardation plates can be canceled (that is, compensated). As a result, during the operation of the liquid crystal device, the phase difference of the light generated when the light emitted from the light source passes through the liquid crystal composed of the liquid crystal molecules inclined by, for example, the pretilt angle is expressed as the first and second positions. It can be compensated by a phase difference plate. Therefore, it is possible to prevent the light that has passed through the liquid crystal panel from entering the output-side polarizing plate in a phase-shifted state. As a result, for example, in the polarizing plate on the output side, the possibility that light that should not be allowed to leak is reduced, and it is possible to prevent a decrease in contrast and a reduction in viewing angle.

  In addition, the first retardation plate and the second retardation plate are disposed between the pair of polarizing plates. More specifically, the retardation plate is disposed between one polarizing plate and the liquid crystal panel of the pair of polarizing plates, or between the other polarizing plate and the liquid crystal panel of the pair of polarizing plates. . In other words, it is provided between the pair of polarizing plates and on the side where light is incident on the liquid crystal panel or the side where light is emitted.

  Here, for example, by using a retardation plate in which the direction of the optical axis is along the thickness direction, such as a retardation plate having uniaxial refractive index anisotropy, and by inclining the retardation plate, When compensating for the optical anisotropy of liquid crystal molecules, the contrast in the liquid crystal device is reduced because the space for tilting the retardation plate is limited, for example, from the viewpoint of the cooling effect due to air circulation. It is technically difficult to appropriately prevent this. Or the mechanism which inclines this phase difference plate will become complicated, and the adjustment which inclines a phase difference plate will become technically difficult in an assembly process.

  However, in the present invention, in particular, as described above, the uniaxial optical axis of the uniaxial refractive index anisotropy of the vertical vapor deposition film constituting the first retardation plate, in other words, the main axis of the refractive index anisotropic medium. Since the direction in which the optical axis of the refractive index nxc ′ (or nyc ′) extends intersects the major axis direction of the liquid crystal molecules inclined by the pretilt angle, the first position in the plane direction of the vertical deposition film (or the first substrate) The minor axis of the vertical axis of the vertical vapor deposition film constituting the phase difference plate (that is, one specific example of the uniaxial optical axis according to the present invention) and the long axis are optical isotropy of the optical anisotropy of liquid crystal molecules. Compensate to go to sex.

  In addition, in the present invention, in particular, as described above, the first vapor deposition film included in the first retardation plate has the first refractive index anisotropy and the optical axis of the first refractive index anisotropy. Diagonal vapor deposition is performed on the first substrate so as to incline in a first direction that cancels a change in light characteristics due to the pretilt. Typically, the first optical axis of the first refractive index anisotropy of the first retardation plate is compensated for the optical anisotropy of the liquid crystal molecules by oblique deposition of the first vapor deposition film. It intersects the first substrate at a first predetermined angle toward the first predetermined direction. Therefore, the oblique deposition of the first vapor deposition film causes the first optical axis of the first refractive index anisotropy of the first retardation plate to be inclined and the first refractive index difference of the first retardation plate. By adjusting the first angle at which the anisotropic first optical axis intersects the first substrate, the optical anisotropy of the liquid crystal molecules of the liquid crystal panel can be easily and accurately compensated.

  In addition, in the present invention, in particular, as described above, the second vapor deposition film included in the second retardation plate retains the second refractive index anisotropy and the light having the second refractive index anisotropy. The axis is obliquely deposited on the second substrate so as to cancel the change in light characteristics due to the pretilt and to incline in a second direction different from the first direction. Typically, the second optical axis of the second refractive index anisotropy of the second retardation plate is compensated for the optical anisotropy of the liquid crystal molecules by oblique deposition of the second deposited film. It intersects the second substrate at a second predetermined angle in the second predetermined direction. Therefore, the second direction in which the second optical axis of the second refractive index anisotropy of the second retardation plate is inclined and the second refractive index difference of the second retardation plate are inclined by oblique vapor deposition of the second vapor deposition film. By adjusting the second angle at which the isotropic second optical axis intersects the second substrate, the optical anisotropy of the liquid crystal molecules of the liquid crystal panel can be easily and accurately compensated.

  In particular, each of the three types of refractive index anisotropy, the uniaxial refractive index anisotropy, the first refractive index anisotropy, and the second refractive index anisotropy described above, is an optical property of the liquid crystal molecule. By compensating for anisotropy, the compensation effect can be significantly improved. Typically, the optical anisotropy of liquid crystal molecules is more accurately adjusted by adjusting the above-mentioned three parameters, namely, the uniaxial refractive index, and the more physical quantities of the first direction and the second direction. Can be compensated for.

  In addition, in order to compensate for the optical anisotropy of the liquid crystal molecules of the liquid crystal panel, there is little or no need to incline the retardation plate itself with respect to the light incident direction. The step of adjusting the tilt of the liquid crystal molecules can be omitted, and the optical anisotropy of the liquid crystal molecules can be compensated and the contrast can be increased easily and at low cost. As a result, according to the liquid crystal device of the present invention, the effect of compensating the phase difference generated in the liquid crystal by the retardation plate can be enhanced, and the contrast can be increased.

  As described above, according to the liquid crystal device of the present invention, the first refractive index anisotropy of the first retardation plate is obtained by the uniaxial refractive index of the vertical vapor deposition film and the oblique vapor deposition of the first vapor deposition film. Adjusting the first direction in which one optical axis is inclined and the second direction in which the second optical axis of the second refractive index anisotropy in the second retardation plate is inclined by oblique vapor deposition of the second vapor deposition film. Thus, the phase difference generated in the liquid crystal panel can be reliably compensated by the first and second phase difference plates. As a result, a high-contrast and high-quality display can be obtained.

  In one aspect of the liquid crystal device of the present invention, the thickness of the vertical vapor deposition film and the refractive index in the thickness direction of the vertical vapor deposition film are the one polarized light positioned on the light emission side of the pair of polarizing plates. The phase difference is set to be 20 nm or less (for example, 10 to 20 (nm)) when the polar angle indicating the angle of the line of sight when viewed from the front of the plate is 0 degree is 30 °.

  According to this aspect, the phase difference caused by the vertical vapor deposition film can be adjusted with high accuracy.

  In one aspect of the liquid crystal device of the present invention, the first direction and the second direction are in a positional relationship sandwiching the major axis direction of the liquid crystal molecules to which the pretilt is applied.

  According to this aspect, it is possible to increase the angle at which the major axis direction of the liquid crystal molecules and the first optical axis of the first refractive index anisotropy extending along the first direction intersect, and the liquid crystal molecules It is possible to increase the angle at which the major axis direction and the second optical axis of the second refractive index anisotropy extending along the second direction intersect. As a result, the refractive index ellipsoid formed by the liquid crystal molecules and the first and second retardation plates can be brought close to the refractive index sphere in three dimensions, so that the optical anisotropy of the liquid crystal molecules can be optically increased. It is possible to compensate more appropriately so as to move toward the isotropic direction, and to obtain a display with higher contrast and higher quality.

  In another aspect of the liquid crystal device of the present invention, a relation angle that is an angle formed by the first direction and the second direction is 70 degrees to 110 degrees.

  According to this aspect, the refractive index anisotropy formed by combining the first refractive index anisotropy and the second refractive index anisotropy can be made biaxial. Typically, research by the present inventor has shown that the relationship angle is 70 to 110 degrees to achieve higher contrast, ideally 90. As a result, the optical anisotropy of the liquid crystal molecules can be more appropriately compensated toward the optical isotropy, and a higher contrast and higher quality display can be obtained.

  In another aspect of the liquid crystal device of the present invention, at least one of the first refractive index anisotropy and the second refractive index anisotropy is biaxial.

  According to this aspect, in addition to or instead of the first direction in which the optical axis of the biaxial first refractive index anisotropy is tilted, the optical axis of the biaxial second refractive index anisotropy is tilted. By adjusting the second direction, the component in the direction perpendicular to the major axis direction of the liquid crystal molecules can be increased. As a result, the refractive index ellipsoid formed by the liquid crystal molecules and the first and second retardation plates can be accurately approximated three-dimensionally to the refractive index sphere.

  In another aspect of the liquid crystal device of the present invention, the first refractive index anisotropy is obtained when the first optical axis is the X axis and the refractive index in the X axis direction (for example, nx ′) is the refractive index in the Y axis direction. In addition to or instead of having a magnitude relationship that the refractive index in the Y-axis direction is larger than the refractive index (for example, ny ′) and the refractive index in the Y-axis direction is larger than the refractive index in the Z-axis direction (for example, nz ′). The anisotropy is that when the second optical axis is the X axis, the refractive index in the X axis direction (for example, nx ″) is larger than the refractive index in the Y axis direction (for example, ny ″), and the Y axis The refractive index in the direction has a magnitude relationship that is larger than the refractive index in the Z-axis direction (for example, nz ″).

  According to this aspect, in the first retardation plate, in addition to or instead of the first direction in which the optical axis in the X-axis direction of the first refractive index anisotropy is inclined, By adjusting the second direction in which the optical axis in the X-axis direction of the rate anisotropy is inclined, the component in the direction orthogonal to the major axis direction of the liquid crystal molecules can be increased. As a result, the refractive index ellipsoid formed by the liquid crystal molecules and the first and second retardation plates can be accurately approximated three-dimensionally to the refractive index sphere.

  In another aspect of the liquid crystal device of the present invention, a first front phase difference that is a phase difference in the front direction of the first phase difference plate and a second front position that is a phase difference in the front direction of the second phase difference plate. It is different from the phase difference.

  According to this aspect, the effect of the compensation can be remarkably improved by individually compensating the optical anisotropy of the liquid crystal molecules by each of the two types of retardation plates. Typically, in addition to the above-described two parameters, the first direction and the second direction, by adjusting more physical quantities of the first front phase difference and the second front phase difference, the optical properties of the liquid crystal molecules are adjusted. Anisotropy can be compensated with higher accuracy. The first front phase difference may be set based on the thickness of the first phase difference plate, and the second front phase difference may be set based on the thickness of the second phase difference plate.

  Typically, one polarizing plate located on the light emission side of the pair of polarizing plates is affected by the first front phase difference and the second front phase difference plate different from the first front phase difference. By changing the front phase difference, which is the phase difference in the front direction, to a greater degree, in the process of incorporating the liquid crystal device into the projector, the contrast that can be realized by rotating the phase difference plate around the direction of incidence of the incident light as a rotation axis Can be limited to a predetermined range (for example, a range of ± 5 degrees). Therefore, since the retardation plate is rotated within a limited predetermined range, the maximum contrast in terms of the function of the projector can be adjusted more easily.

  In another aspect of the liquid crystal device of the present invention, the pair of transmission axes of the pair of polarizing plates are orthogonal to each other and are given the pretilt when viewed from the normal direction of the first substrate or the second substrate. In the first retardation plate, the first optical axis is along one direction of the pair of transmission axes, and the second retardation plate has a 45 ° angle with the major axis direction of the liquid crystal molecules. The second optical axis is along the other direction of the pair of transmission axes.

  According to this aspect, the first and second retardation plates can be more easily incorporated into the liquid crystal device.

  In another aspect of the liquid crystal device of the present invention, at least one of the vertical vapor deposition film, the first vapor deposition film, and the second vapor deposition film includes an inorganic material.

  According to this aspect, for example, an inorganic material such as Ta2O5 can effectively prevent the first and second retardation plates from being deteriorated due to light irradiation and accompanying temperature rise, and a liquid crystal device having excellent reliability can be obtained. Can be configured.

  In another aspect of the liquid crystal device of the present invention, at least one of the first retardation plate and the second retardation plate is rotatable about the one normal direction as a rotation axis.

  According to this aspect, by rotating at least one phase difference plate about the normal direction described above as a rotation axis, the direction in which the optical axis of refractive index anisotropy of at least one phase difference plate is inclined, and at least By adjusting the angle at which the optical axis of the refractive index anisotropy of one phase difference plate intersects the first substrate, the optical anisotropy of the liquid crystal molecules of the liquid crystal panel can be easily and accurately compensated. it can.

  In another aspect of the liquid crystal device of the present invention, the one deposited film is obliquely deposited in addition to or instead of the thickness of at least one deposited film of the first deposited film and the deposited film. The deposition angle is set such that (i) a front phase difference, which is a front phase difference when viewed from the light exit side of the retardation plate, is within a first predetermined range, (ii ) A first phase difference generated when the light is incident from a first direction that is different from a normal direction of the retardation plate and along which the one deposited film is obliquely deposited. The ratio of the second phase difference generated when the light is incident from a second direction that is symmetrical to the first direction with respect to the normal direction is within a second predetermined range. Is set.

  According to this aspect, in addition to or instead of the thickness of one vapor deposition film, the vapor deposition angle, which is an angle at which one vapor deposition film is obliquely vapor deposited, is viewed from (i) the light exit side of the phase difference plate. The front phase difference, which is the phase difference in the front direction, is set to be within the first predetermined range. In addition to this, in addition to or instead of the film thickness of one vapor deposition film, the vapor deposition angle is different from (ii) the normal direction of the phase difference plate and the vapor deposition direction in which one vapor deposition film is obliquely vapor deposited. The first phase difference that occurs when light is incident from the first direction along the direction and the second phase that is symmetric with respect to the first direction with respect to the normal direction. The ratio with respect to the second phase difference is set to be within the second predetermined range. Here, the first predetermined range according to the present invention is individually and specifically defined by theoretical, experimental, empirical, or simulation so as to increase the contrast of light emitted from the liquid crystal device. The range of the front phase difference. Further, the second predetermined range according to the present invention is individually and specifically defined by theoretical, experimental, empirical, or simulation so as to increase the contrast of light emitted from the liquid crystal device. It means the range of the value of the ratio between the first phase difference and the second phase difference.

  As a result, in addition to or instead of the film thickness of one vapor deposition film, the vapor deposition angle is set to the ratio between the front phase difference in the first predetermined range and the first phase difference and the second phase difference in the second predetermined range. Accordingly, a retardation plate capable of improving the contrast in the liquid crystal device can be realized more simply by setting the value appropriately. In other words, in addition to the variables and parameters that directly specify the properties and performance of the phase difference plate, the position is determined by a wider variety of variables and parameters, such as variables and parameters that indirectly specify the properties and performance of the phase difference plate. By defining the properties and performance of the retardation plate, the contrast in the liquid crystal device can be improved with higher accuracy.

  In another aspect of the liquid crystal device of the present invention, the film thickness and the vapor deposition angle are: (i) when the retardation plate is rotated about the normal direction as the rotation axis as the front phase difference increases. In addition to or instead of being set so that the change amount of contrast with respect to the unit change amount of the rotation angle of (ii) is increased, the change amount of the contrast with respect to the unit change amount as the front phase difference becomes smaller Is set to be small.

  According to this aspect, in addition to the setting of the ratio between the first phase difference and the second phase difference described above, the front phase difference is set to an appropriate value, so that in the assembly process of manufacturing the projector, or the user In this adjustment operation, a desired adjustment angle range of the retardation film can be determined easily and appropriately, which is very advantageous in practice. Typically, in the assembly process of manufacturing a projector, as the film thickness and vapor deposition angle increase in front phase difference, the unit change of the rotation angle when rotating the retardation plate around the normal direction as the rotation axis When the amount of change in contrast with respect to the amount is set to be large, the amount of change in contrast can be detected accurately and quickly because the amount of change in contrast is large. Thereby, the rotation angle of the phase difference plate that can realize the maximum contrast can be determined and set more quickly. Or, typically, in the adjustment operation of the user, when the film thickness and the deposition angle are set so that the amount of change in contrast with respect to the unit change amount becomes smaller as the front phase difference becomes smaller, the amount of change in contrast Therefore, the rotation angle of the retardation plate capable of realizing the maximum contrast can be widened. Thereby, for example, the rotation angle of the phase difference plate that can realize the maximum contrast even by user's visual recognition can be determined and set more easily.

In another liquid crystal device according to another embodiment of the present invention, a vertical alignment type liquid crystal including liquid crystal molecules provided with a pretilt by the alignment film is sandwiched between a pair of substrates each having an alignment film. A liquid crystal panel to be modulated, a pair of polarizing plates disposed between the liquid crystal panels, and a pair of polarizing plates; (ia) a first substrate; and (ii-a) a first refractive index difference. A first vapor deposited obliquely on the first substrate such that a first optical axis of the first refractive index anisotropic medium having a tilt is inclined in a first direction that cancels a change in the characteristic of the light due to the pretilt; A first retardation plate having a vapor deposition film and a second refractive index anisotropy disposed between the pair of polarizing plates and having (ib) a second substrate and (ii-b) a second refractive index anisotropy The second optical axis of the medium cancels the characteristic change of the light due to the pretilt and is different from the first direction. A uniaxial refractive index anisotropically disposed between the second retardation plate having a second deposited film obliquely deposited on the second substrate so as to incline in two directions and the pair of polarizing plates. And a third retardation plate in which a uniaxial optical axis of the uniaxial refractive index anisotropic medium having a property extends along the thickness direction, and the first retardation plate is a normal line of the substrate of the liquid crystal panel The second retardation plate can be rotated about the normal line independently of the first retardation plate.
In the second liquid crystal device according to the present invention, a vertical alignment type liquid crystal composed of liquid crystal molecules pretilted by the alignment film is sandwiched between a pair of substrates each having an alignment film. A liquid crystal panel that modulates the liquid crystal panel, a pair of polarizing plates arranged with the liquid crystal panel sandwiched therebetween, and (ia) a first substrate, and (ii-a) a first refractive index. The first optical axis of the first refractive index anisotropy having anisotropy is obliquely vapor-deposited on the first substrate so as to incline in a first direction that cancels the light characteristic change due to the pretilt. It is disposed between a first retardation plate (15a described later) having one deposited film and the pair of polarizing plates, and has (ib) a second substrate and (ii-b) a second refractive index anisotropy. The second optical axis of the second refractive index anisotropy cancels the change in the characteristic of the light due to the pretilt and A second retardation plate (15e, which will be described later) having a second deposited film obliquely deposited on the second substrate so as to be inclined in a second direction different from the one direction, and the pair of polarizing plates. A third retardation plate having a uniaxial refractive index anisotropy and a uniaxial optical axis of the uniaxial refractive index anisotropy along the thickness direction (15f, so-called C plate described later). ).

  According to the second liquid crystal device of the present invention, the light emitted from the light source is, for example, a color separation optical system such as a reflection mirror and a dichroic mirror in substantially the same manner as the first liquid crystal device of the present invention described above. Is separated into red light, green light and blue light. The liquid crystal panel is used as a light valve that modulates red light, green light, and blue light, for example. In the liquid crystal panel, for example, the alignment state of liquid crystal molecules of each pixel is regulated according to a data signal (or image signal), and an image corresponding to the data signal is displayed in the display area. An image displayed by each liquid crystal panel is synthesized by a color synthesis optical system such as a dichroic prism, and projected onto a projection surface such as a screen as a projection image via a projection lens.

  In particular, the first retardation plate is disposed between the pair of polarizing plates, and maintains (ia) the first substrate and (ii-a) the first refractive index anisotropy and the first refractive index anisotropy. The first deposited film is obliquely deposited on the first substrate so that the first optical axis is inclined in a direction that cancels the change in light characteristics due to the pretilt. The second retardation plate is disposed between the pair of polarizing plates, and holds (ib) the second substrate and (ii-b) the second refractive index anisotropy and the second refractive index anisotropy second. A second deposited film is obliquely deposited on the second substrate so that the optical axis cancels the light characteristic change due to the pretilt and is inclined in a second direction different from the first direction. The third retardation plate is disposed between the pair of polarizing plates, and maintains the uniaxial refractive index anisotropy and the uniaxial optical axis of the uniaxial refractive index anisotropy is along the thickness direction. .

  As described above, according to the second liquid crystal device of the present invention, the direction in which the first optical axis of the first refractive index anisotropy in the first retardation plate is tilted by oblique vapor deposition of the first vapor deposition film. And an angle at which the first optical axis intersects the first substrate. In addition, the direction in which the second optical axis of the second refractive index anisotropy in the second phase difference plate is inclined by oblique vapor deposition of the second vapor deposition film, and the angle at which the second optical axis intersects the second substrate. Adjust. In addition, since the uniaxial optical axis of the uniaxial refractive index anisotropy of the third phase difference plate is along the thickness direction, the first to third phase difference plates ensure the phase difference generated in the liquid crystal panel. Can be compensated for. As a result, a high-contrast and high-quality display can be obtained.

  In particular, the first retardation plate, the second retardation plate, and the third retardation plate are disposed at different optical positions, or at least one of the first to third retardation plates is temporarily placed. Therefore, the optical adjustment can be easily performed. In addition, since the manufacturing method and material of the first to third retardation plates can be varied, optical adjustment can be performed at a lower cost.

Note that the second liquid crystal device of the present invention can appropriately adopt the same aspects as the various aspects of the first liquid crystal device of the present invention described above.
(projector)
In order to solve the above problems, a first projector according to the present invention includes the above-described first liquid crystal device according to the present invention (including various aspects), a light source that emits the light, and the modulated light. And a projection optical system for projecting.

  According to the first projector of the present invention, the light emitted from the light source is color-separated into red light, green light, and blue light by a color separation optical system such as a reflection mirror and a dichroic mirror. The liquid crystal panel described above is used as a light valve that modulates red light, green light, and blue light, for example. In the liquid crystal panel, for example, the alignment state of liquid crystal molecules of each pixel is regulated according to a data signal (or image signal), and an image corresponding to the data signal is displayed in the display area. An image displayed by each liquid crystal panel is synthesized in a projection optical system by a color synthesis optical system such as a dichroic prism, and projected onto a projection surface such as a screen as a projection image via a projection lens.

  In substantially the same manner as the first liquid crystal device of the present invention described above, the first refractive index anisotropy in the first retardation plate is obtained by uniaxial refractive index of the vertical vapor deposition film and oblique vapor deposition of the first vapor deposition film. The first direction in which the first optical axis is inclined and the second direction in which the second optical axis of the second refractive index anisotropy in the second retardation plate is inclined are adjusted by oblique vapor deposition of the second vapor deposition film. Thus, the phase difference generated in the liquid crystal panel can be reliably compensated by the first and second phase difference plates. As a result, a high-contrast and high-quality display can be obtained.

  Note that the first projector of the present invention can appropriately adopt the same aspects as the various aspects of the first liquid crystal device of the present invention described above.

  In order to solve the above problems, a second projector according to the present invention includes the above-described second liquid crystal device according to the present invention (including various aspects), a light source that emits the light, and the modulated light. And a projection optical system for projecting.

  According to the second projector of the present invention, the light emitted from the light source is color-separated into red light, green light, and blue light by a color separation optical system such as a reflection mirror and a dichroic mirror. The liquid crystal panel described above is used as a light valve that modulates red light, green light, and blue light, for example. In the liquid crystal panel, for example, the alignment state of liquid crystal molecules of each pixel is regulated according to a data signal (or image signal), and an image corresponding to the data signal is displayed in the display area. An image displayed by each liquid crystal panel is synthesized in a projection optical system by a color synthesis optical system such as a dichroic prism, and projected onto a projection surface such as a screen as a projection image via a projection lens.

  In almost the same manner as the above-described second liquid crystal device of the present invention, a high-contrast and high-quality display can be obtained. In particular, the first retardation plate, the second retardation plate, and the third retardation plate are disposed at different optical positions, or at least one of the first to third retardation plates is temporarily placed. Therefore, the optical adjustment can be easily performed. In addition, since the manufacturing method and material of the first to third retardation plates can be varied, optical adjustment can be performed at a lower cost.

Note that the second projector of the present invention can appropriately adopt the same aspects as the various aspects of the second liquid crystal device of the present invention described above.
(Optical compensation method for liquid crystal device)
According to an optical compensation method of a liquid crystal device of one embodiment of the present invention, at least one of the first retardation plate and the second retardation plate is used with a normal line of the liquid crystal panel as a rotation axis. A first optical adjustment step to rotate, and a second optical to rotate the other retardation plate of the first retardation plate and the second retardation plate about the normal line of the substrate of the liquid crystal panel. An adjustment step.
In order to solve the above problems, an optical compensation method for a liquid crystal device according to the present invention is an optical compensation method for performing optical compensation in the above-described liquid crystal device according to the present invention (including various aspects). An optical adjustment step of rotating at least one of the phase difference plate and the second phase difference plate with the normal direction of the one phase difference plate as a rotation axis.

  According to the optical compensation method of the liquid crystal device of the present invention, in the step of incorporating the light source, the polarizing plate, and the first or second retardation plate into the above-described liquid crystal device of the present invention, in the optical adjustment step, the first retardation plate. In addition, at least one of the second retardation plates is rotated with a normal direction of the liquid crystal panel, which is an incident direction in which light is incident, as a rotation axis. Thereby, the relative positional relationship between the optical axis of the one phase difference plate and the major axis direction of the liquid crystal molecules can be adjusted, and higher contrast can be realized. In addition, by adjusting the front phase difference of this one phase difference plate, the rotation angle of this one phase difference plate is limited to be within a predetermined range, and consequently, this one phase difference plate is limited. Since the rotation is performed within a predetermined range, the contrast can be adjusted more easily.

  In particular, in addition to the three parameters described above, namely the three physical quantities of uniaxial refractive index, first direction and second direction, the angle between the major axis direction of the tilted liquid crystal molecules and the first direction More physical quantities such as the corresponding rotation angle of the first retardation plate and the rotation angle of the second retardation plate corresponding to the angle between the major axis direction of the tilted liquid crystal molecules and the second direction. By adjusting, the optical anisotropy of liquid crystal molecules can be compensated with higher accuracy.

  In addition to the optical adjustment step described above, another optical adjustment step may be provided in which the pair of polarizing plates is rotated with the normal direction of the first and second retardation plates as the rotation axis. Thereby, for example, a normally black liquid crystal or a normally white liquid crystal can be easily realized.

  In the optical compensation method of the liquid crystal device of the present invention, it is possible to appropriately adopt the same aspects as the various aspects of the first and second liquid crystal devices of the present invention described above.

In another liquid crystal device according to another embodiment of the present invention, a vertical alignment type liquid crystal including liquid crystal molecules provided with a pretilt by the alignment film is sandwiched between a pair of substrates each having an alignment film. A liquid crystal panel to be modulated, a pair of polarizing plates disposed between the liquid crystal panels, and a pair of polarizing plates; (ia) a first substrate; and (ii-a) a uniaxial refractive index difference. A vertically deposited film vertically deposited on one side of the first substrate so that the uniaxial optical axis of the anisotropic uniaxial refractive index anisotropic medium is along the thickness direction, and (iii-a) first refraction Diagonal evaporation on the other side of the first substrate so that the first optical axis of the first refractive index anisotropic medium having refractive index anisotropy is inclined in a first direction that cancels the light characteristic change due to the pretilt. A first retardation plate having a first deposited film and a pair of polarizing plates, and (ib) a second substrate And (ii-b) the second optical axis of the second refractive index anisotropic medium having the second refractive index anisotropy cancels the characteristic change and is inclined in a second direction different from the first direction. A second retardation plate having a second deposited film obliquely deposited on the second substrate, and the first retardation plate is rotatable about the normal line of the substrate of the liquid crystal panel. The second retardation plate can be rotated about the normal line independently of the first retardation plate.
The liquid crystal device according to the present invention modulates light by sandwiching a vertical alignment type liquid crystal composed of liquid crystal molecules provided with a pretilt by the alignment film between a pair of substrates each having an alignment film. A liquid crystal panel, a pair of polarizing plates arranged between the liquid crystal panels, and a pair of polarizing plates, (ia) a first substrate, (ii-a) uniaxial refractive index anisotropy A vertically deposited film vertically deposited on one side of the first substrate so that the uniaxial optical axis of the uniaxial refractive index anisotropy is along the thickness direction, and (iii-a) a first refractive index The first optical axis having anisotropy and the first refractive index anisotropy is obliquely vapor-deposited on the other side of the first substrate so as to incline in a first direction that cancels the light characteristic change due to the pretilt. And (ib) a second substrate, disposed between the first retardation plate having the first vapor deposition film and the pair of polarizing plates. And (ii-b) having a second refractive index anisotropy so that the second optical axis of the second refractive index anisotropy cancels the characteristic change and tilts in a second direction different from the first direction. A second retardation plate having a second deposited film obliquely deposited on the second substrate.

  For example, when a vertical vapor deposition film such as a C plate is formed on the first vapor deposition film obliquely deposited by a sputtering technique, or the first vapor deposition film is oblique on a vertical vapor deposition film such as a C plate. In the case of forming by the vapor deposition technique, moisture is mixed into the vertical vapor deposition film during the formation process, and this causes a technical problem that the quality of the vertical vapor deposition film is deteriorated.

  On the other hand, according to the third liquid crystal device of the present invention, for example, a vertical vapor deposition film such as a C plate is formed on one surface of the first substrate, and the first vapor deposition film is formed on the other surface of the first substrate. Form on the surface. As a result, when a vertical vapor deposition film such as a C plate is formed by a sputtering method, the degree of moisture mixed into the vertical vapor deposition film can be reduced, so that the quality of the vertical vapor deposition film can be further improved. it can.

  In another aspect of the liquid crystal device of the present invention, the vertical vapor deposition film is disposed farther from the liquid crystal panel than the first vapor deposition film.

  According to this aspect, in general, a vertical vapor deposition film such as a C plate, for example, generates minute bubbles in the manufacturing process, and is included in the vertical vapor deposition film to a greater or lesser extent. On the other hand, according to this aspect, the vertical vapor deposition film is disposed at a distance farthest from the liquid crystal panel as compared with the first vapor deposition film. As a result, the degree of focusing on the bubbles contained in the vertical vapor deposition film can be significantly reduced. Thereby, it can suppress effectively that the bubble contained in a perpendicular | vertical vapor deposition film is projected, and has a bad influence on a projection image | video.

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

(First embodiment)
FIG. 1 is a schematic configuration diagram of a liquid crystal projector according to an embodiment of the present invention. The projector 10 is a front projection type projector that projects an image on a screen 11 provided in front. The projector 10 includes a light source 12, dichroic mirrors 13 and 14, liquid crystal light valves 15 to 17, a projection optical system 18, a cross dichroic prism 19, and a relay system 20.

  The light source 12 is composed of an ultrahigh pressure mercury lamp that supplies light including red light, green light, and blue light. The dichroic mirror 13 is configured to transmit the red light LR from the light source 12 and reflect the green light LG and the blue light LB. The dichroic mirror 14 is configured to transmit the blue light LB and reflect the green light LG among the green light LG and the blue light LB reflected by the dichroic mirror 13. As described above, the dichroic mirrors 13 and 14 constitute a color separation optical system that separates the light emitted from the light source 12 into the red light LR, the green light LG, and the blue light LB. Between the dichroic mirror 13 and the light source 12, an integrator 21 and a polarization conversion element 22 are sequentially arranged from the light source 12. The integrator 21 makes the illuminance distribution of the light emitted from the light source 12 uniform. The polarization conversion element 22 converts the light from the light source 12 into polarized light having a specific vibration direction such as s-polarized light.

  The liquid crystal light valve 15 is a transmissive liquid crystal device (electro-optical device) that modulates the red light LR transmitted through the dichroic mirror 13 and reflected by the reflection mirror 23 in accordance with an image signal. The liquid crystal light valve 15 includes a first polarizing plate 15b, a liquid crystal panel 15c, a first retardation plate 15a, a second retardation plate 15e, and a second polarizing plate 15d.

  Here, the red light LR incident on the liquid crystal light valve 15 passes through the first polarizing plate 15b and is converted into, for example, s-polarized light. The liquid crystal panel 15c converts the incident s-polarized light into p-polarized light (circularly polarized light or elliptically polarized light in the case of halftone) by modulation according to the image signal. Furthermore, the second polarizing plate 15d is a polarizing plate that blocks s-polarized light and transmits p-polarized light. Therefore, the liquid crystal light valve 15 is configured to modulate the red light LR in accordance with the image signal and to emit the modulated red light LR toward the cross dichroic prism 19.

  The liquid crystal light valve 16 modulates the green light LG reflected by the dichroic mirror 13 after being reflected by the dichroic mirror 13 in accordance with the image signal, and emits the modulated green light LG toward the cross dichroic prism 19. This is a transmissive liquid crystal device. Similarly to the liquid crystal light valve 15, the liquid crystal light valve 16 includes a first polarizing plate 16b, a liquid crystal panel 16c, a first retardation plate 16a, a second retardation plate 16e, and a second polarizing plate 16d. .

  The liquid crystal light valve 17 reflects the blue light LB reflected by the dichroic mirror 13, passes through the dichroic mirror 14 and then passes through the relay system 20 according to the image signal, and directs the modulated blue light LB to the cross dichroic prism 19. A transmissive liquid crystal device that emits light. Similarly to the liquid crystal light valves 15 and 16, the liquid crystal light valve 17 includes a first polarizing plate 17b, a liquid crystal panel 17c, a first retardation plate 17a, a second retardation plate 17e, and a second polarizing plate 17d. ing.

  The relay system 20 includes relay lenses 24a and 24b and reflection mirrors 25a and 25b. The relay lenses 24a and 24b are provided to prevent light loss due to the long optical path of the blue light LB. The relay lens 24a is disposed between the dichroic mirror 14 and the reflection mirror 25a. The relay lens 24b is disposed between the reflection mirrors 25a and 25b. The reflection mirror 25a is disposed so as to reflect the blue light LB transmitted through the dichroic mirror 14 and emitted from the relay lens 24a toward the relay lens 24b. The reflection mirror 25 b is disposed so as to reflect the blue light LB emitted from the relay lens 24 b toward the liquid crystal light valve 17.

  The cross dichroic prism 19 is a color combining optical system in which two dichroic films 19a and 19b are arranged orthogonally in an X shape. The dichroic film 19a reflects the blue light LB and transmits the green light LG. The dichroic film 19b reflects the red light LR and transmits the green light LG. Therefore, the cross dichroic prism 19 is configured to combine the red light LR, the green light LG, and the blue light LB modulated by the liquid crystal light valves 15 to 17 and emit the resultant light toward the projection optical system 18. Yes. The projection optical system 18 has a projection lens (not shown) and is configured to project the light combined by the cross dichroic prism 19 onto the screen 11.

  The liquid crystal light valves 15 and 17 for red and blue are provided with λ / 2 phase difference plates, and light incident on the cross dichroic prism 19 from these liquid crystal light valves 15 and 17 is set as s-polarized light. As the configuration without the λ / 2 retardation plate, a configuration in which the light incident on the cross dichroic prism 19 from the liquid crystal light valve 16 is p-polarized light can be employed. By making the light incident on the cross dichroic prism 19 into different types of polarized light, an optimized color synthesis optical system can be configured in consideration of the reflection characteristics of the dichroic films 19a and 19b. In general, since the dichroic films 19a and 19b have excellent reflection characteristics of s-polarized light, as described above, the red light LR and the blue light LB reflected by the dichroic films 19a and 19b are made s-polarized, and the dichroic films 19a and 19b are used. The transmitted green light LG may be p-polarized light.

(LCD light valve)
Next, the liquid crystal light valves (liquid crystal devices) 15 to 17 will be described.

  The liquid crystal light valves 15-17 differ only in the wavelength range of the light to be modulated, and the basic configuration is the same. Therefore, hereinafter, the liquid crystal panel 15c and the liquid crystal light valve 15 including the same will be described as an example.

  FIG. 2 is an overall configuration diagram of the liquid crystal panel according to the present embodiment (FIG. 2A) and a sectional configuration diagram along line HH ′ of FIG. 2A (FIG. 2B). . FIG. 3 is an explanatory diagram showing the configuration of the liquid crystal light valve according to the present embodiment. FIG. 4 is a diagram showing an optical axis arrangement of each component in FIG.

  As shown in FIG. 2, the liquid crystal panel 15 c includes a counter substrate 31 and a TFT array substrate 32 that are disposed so as to face each other, and are bonded to each other via a seal material 33. A liquid crystal layer 34 is sealed in a region surrounded by the counter substrate 31, the TFT array substrate 32, and the sealing material 33. The liquid crystal layer 34 is made of a liquid crystal having negative dielectric anisotropy. In the liquid crystal panel 15c of the present embodiment, as shown in FIG. The structure is vertically aligned with a pretilt angle.

  The liquid crystal panel 15 c has a liquid crystal layer 34 sealed in a region partitioned by the TFT array substrate 32, the counter substrate 31 and the sealing material 33. In the liquid crystal panel 15c, a light shielding film 35 is formed inside the region where the sealing material 33 is formed. An inter-substrate conductive material 57 for providing electrical continuity between the TFT array substrate 32 and the counter substrate 31 is disposed at a corner on the outer peripheral side of the sealing material 33.

  A data line driving circuit 71, an external circuit mounting terminal 75, and two scanning line driving circuits 73 are formed in a region outside the formation region of the sealing material 33 in a plan view of the TFT array substrate 32. Further, a plurality of wirings 74 for connecting between the scanning line driving circuits 73 provided on both sides of the image display region are also formed in the region of the TFT array substrate 32. Instead of forming the data line driving circuit 71 and the scanning line driving circuit 73 on the TFT array substrate 32, for example, a TAB (TapeAutomatedBonding) substrate on which a driving LSI is mounted and terminals formed on the periphery of the TFT array substrate 32 The group may be electrically and mechanically connected through an anisotropic conductive film.

  The counter substrate 31 is a microlens substrate (light collecting substrate) having a plurality of microlenses arranged in a plane, as shown in FIG. The counter substrate 31 is mainly composed of a substrate 92, a resin layer 93, and a cover glass 94.

  The substrate 92 and the cover glass 94 are transparent substrates made of glass or the like, and substrates made of quartz, borosilicate glass, soda lime glass (blue plate glass), crown glass (white plate glass), or the like can also be used. A plurality of concave portions (microlenses) 95 are formed on the liquid crystal layer 34 side (the lower surface side in the drawing) of the substrate 92. The microlens 95 condenses the light incident on the substrate 92 from the side opposite to the liquid crystal layer 34 and emits it to the liquid crystal layer 34 side.

  The resin layer 93 is a layer made of a resin material filled on the microlens 95 of the substrate 92, and is formed using a resin material that can transmit light, such as an acrylic resin. The resin layer 93 is provided so as to cover one side of the substrate 92 and fill the concave interior of the microlens 95. The upper surface of the resin layer 93 is a flat surface, and a cover glass 94 is attached to the flat surface.

  A light shielding film 35, a common electrode 97, and an alignment film 98 are formed on the surface of the microlens substrate 36 on the liquid crystal layer 34 side. The light shielding film 35 is formed on the cover glass 94 in a substantially lattice shape in plan view. The microlenses 95 are located between the light shielding films 35 and are respectively disposed in regions overlapping the pixel region of the liquid crystal panel 15c (region where the pixel electrode 42 is formed) in plan view. The alignment film 98 is a vertical alignment film that aligns liquid crystal molecules constituting the liquid crystal layer 34 substantially perpendicularly to the substrate surface. For example, a silicon oxide film formed with a columnar structure by oblique deposition, It consists of a polyimide film or the like that has been subjected to orientation treatment.

  The TFT array substrate 32 is mainly composed of a transparent substrate 41 made of glass or quartz, a pixel electrode 42 formed on the side surface of the liquid crystal layer 34 of the substrate 41, a TFT 44 for driving the pixel electrode, and an alignment film 43. Has been.

  The pixel electrodes 42 are substantially rectangular conductive films in a plan view made of a transparent conductive material such as ITO, for example, and are arranged in a matrix in a plan view on the substrate 41 as shown in FIG. It is formed in a region overlapping with the microlens 95.

  Although the TFT 44 is simplified in illustration, the TFT 44 is formed on the substrate 41 corresponding to each of the pixel electrodes 42, and usually an area (non-display area, overlapping with the light shielding film 35 on the counter substrate 31 side in a plan view). It is arranged in the light shielding area.

  The alignment film 43 formed so as to cover the pixel electrode 42 is a vertical alignment film made of a silicon oxide film or the like formed by oblique deposition, like the previous alignment film 98.

  The alignment films 43 and 98 are formed such that the alignment directions of each other (the alignment direction of the columnar structures) are substantially parallel in plan view, and the liquid crystal molecules constituting the liquid crystal layer 34 are arranged in a predetermined manner with respect to the substrate surface. The liquid crystal molecules function so as to be aligned substantially vertically with an inclination and to make the inclination direction of the liquid crystal molecules uniform in the substrate surface direction.

  A data line (not shown) and a scanning line (not shown) for connecting the pixel electrode 42 and the TFT 44 are formed in a region on the liquid crystal layer 34 side surface of the substrate 41 that is inside the region where the sealing material 33 is formed in plan view. ) Is formed. The data line and the scanning line are formed in a region overlapping the light shielding film 35 in plan view. A region bordered by the light shielding film 35, the TFT 44, the data line, and the scanning line is a pixel region of the liquid crystal panel 15c. A plurality of pixel areas are arranged in a matrix in plan view to form an image display area.

(Polarizing plate and first and second retardation plates)
As shown in FIG. 3, the liquid crystal light valve 15 is disposed outside the above-described liquid crystal panel 15c, the first polarizing plate 15b disposed outside the counter substrate 31 of the liquid crystal panel 15c, and the TFT array substrate 32. The first retardation film 15a, the second retardation film 15e disposed outside the first retardation film 15a, and the second polarizing plate 15d disposed outside the second retardation film 15e. Has been.

  In the liquid crystal light valve 15 of the present embodiment, the side on which the first polarizing plate 15b is disposed (the upper side in the drawing) is the light incident side, and the side on which the second polarizing plate 15d is disposed is the light emitting side. It is.

  In the liquid crystal panel 15c, the alignment films 43 and 98 facing each other with the liquid crystal layer 34 interposed therebetween are formed, for example, by depositing silicon oxide from an oblique direction shifted by about 50 ° from the substrate normal direction. The film thickness is about 40 nm in all cases. The alignment directions 43a and 98a represented by the arrows attached to the alignment films 43 and 98 in FIG. 3 coincide with the direction in the substrate surface among the vapor deposition directions at the time of formation. The alignment direction 43a in the alignment film 43 and the alignment direction 98a in the alignment film 98 are parallel to each other.

  Then, due to the alignment regulating force of the alignment films 43 and 98, the liquid crystal molecules 51 are aligned in a state tilted by about 2 ° to 8 ° from the substrate normal, and the director direction (pretilt direction P) of the liquid crystal molecules 51 is the substrate surface. The orientation is such that the orientation is along the orientation directions 43a and 98a.

  In each of the first polarizing plate 15b and the second polarizing plate 15d, a polarizing element 151 made of dyed PVA (polyvinyl alcohol) is sandwiched between two protective films 152 made of TAC (triacetyl cellulose). It has a three-layer structure. As shown in FIG. 4, the transmission axis 151b of the first polarizing plate 15b and the transmission axis 151d of the second polarizing plate 15d are arranged orthogonally. The directions of the transmission axes 151b and 151d of these polarizing plates 15b and 15d are shifted by about 45 ° in plan view with respect to the alignment direction (evaporation direction) 43a of the alignment film 43 of the liquid crystal panel 15c.

  The first retardation plate 15a includes (i) a first substrate 1501a, (ii) a vertical deposition film 1501c on which a refractive index anisotropic medium 255c that holds uniaxial refractive index anisotropy is vertically deposited, and iii) a first vapor deposition film 1503a in which a refractive index anisotropic medium having the first refractive index anisotropy is obliquely vapor-deposited, and (iv) a third substrate 1502a.

  The main refractive index in the optical axis direction of the refractive index ellipsoid of the refractive index anisotropic medium 255a is shown on the side of the first vapor deposition film 1503a of the first retardation plate 15a in FIG. In the present embodiment, the main refractive indexes nx ′, ny ′, and nz ′ are configured to satisfy the relationship of nx ′> ny ′> nz ′. That is, the refractive index nx 'in the direction inclined from the normal direction of the substrate 1501a or the substrate 1502a is larger than the refractive indexes ny' and nz 'in the other directions, and the refractive index ellipsoid has a rice grain shape.

  An average refractive index ellipsoid of the refractive index anisotropic medium 255c of the vertical vapor deposition film 1501c is schematically shown on the side of the vertical vapor deposition film 1501c of the first retardation plate 15a in FIG. In this figure, nxc ′ and nyc ′ indicate the main refractive index in the surface direction of the vertical vapor deposition film 1501c, and nzc ′ indicates the main refractive index in the thickness direction of the vertical vapor deposition film 1501c. In this embodiment, the main refractive indexes nxc ′, nyc ′, and nzc ′ are configured to satisfy the relationship nxc ′ = nyc ′> nzc ′. That is, the refractive index nzc 'in the thickness direction is smaller than the refractive index in the other direction, and the refractive index ellipsoid is a disk shape. The refractive index ellipsoid of the refractive index anisotropic medium 255c is oriented parallel to the plate surface of the vertical vapor deposition film 1501c, and the optical axis direction of the vertical vapor deposition film 1501c (the short axis direction of the refractive index ellipsoid). Is parallel to the normal direction of the plate surface.

  The second retardation plate 15e includes (i) a second substrate 1501e, (ii) a second vapor deposition film 1503e on which a refractive index anisotropy medium 255e holding refractive index anisotropy is obliquely vapor deposited, and (iii) And a fourth substrate 1502e. The main refractive index in the optical axis direction of the refractive index ellipsoid of the refractive index anisotropic medium 255e is shown on the side of the second retardation plate 15e in FIG. In the present embodiment, the main refractive indexes nx ″, ny ″, and nz ″ satisfy the relationship of nx ″> ny ″> nz ″. That is, the refractive index nx ″ in the direction inclined from the normal direction of the second substrate 1501e or the fourth substrate 1502e is larger than the refractive indexes ny ″ and nz ″ in the other directions. Become.

  In particular, when viewed from the normal direction of the second retardation plate 15e (or the first retardation plate 15a), the direction in which the optical axis of the main refractive index nx ″ of the second retardation plate 15e is inclined, It is preferable that the optical axis of the main refractive index nx ′ of the one phase difference plate 15a is orthogonal to the direction in which the optical axis is inclined. The details of the first retardation plate 15a and the second retardation plate 15e will be described later.

  Specifically, a biaxial plate can be given as a typical example of the refractive index anisotropic medium 255a (or refractive index anisotropic medium 255e).

(Detailed configuration of the first and second retardation plates)
Here, with reference to FIG. 5 to FIG. 7, a detailed configuration of the first and second phase difference plates according to the present embodiment will be described. FIG. 5 shows a vapor deposition direction that defines the relative positional relationship between the refractive index anisotropic medium constituting the first retardation plate according to this embodiment and the substrate corresponding to the first retardation plate. FIG. 5A is a perspective view schematically showing the vapor deposition angle and the relative angle between the refractive index anisotropic medium constituting the second retardation plate and the substrate corresponding to the second retardation plate. The external perspective view (FIG. 5 (b)) schematically showing the vapor deposition direction and the vapor deposition angle that define a specific positional relationship, and the refractive index anisotropic medium and the second phase difference plate constituting the first phase difference plate FIG. 5C is an external perspective view schematically showing the relative positional relationship between the refractive index anisotropic medium obtained by synthesizing the refractive index anisotropic medium and the substrate. FIG. 6 is a diagram showing the relative positional relationship between the optical axis of the refractive index anisotropic medium constituting the first and second phase difference plates according to the present embodiment and the optical axis of the liquid crystal molecules constituting the liquid crystal panel. FIG. 6 is a plan view (FIG. 6A) and an elevation view (FIG. 6B) schematically shown. FIG. 7 shows the optical characteristics of the refractive index anisotropic medium obtained by synthesizing the refractive index anisotropic medium constituting the first retardation plate and the refractive index anisotropic medium constituting the second retardation plate according to the present embodiment. FIG. 3 is a schematic diagram conceptually showing a state in which optical anisotropy is realized by combining mechanical anisotropy and optical anisotropy of liquid crystal molecules constituting a liquid crystal panel.

  As shown in FIG. 5A, in the vertical vapor deposition film 1501c constituting the first retardation plate 15a, the refractive index anisotropic medium 255c is vertically vapor deposited on the first substrate 1501a as described above. . Specifically, as described above, the main refractive indexes nxc ′, nyc ′, and nzc ′ of the vertical deposition film 1501c satisfy the relationship nxc ′ = nyc ′> nzc ′.

  In addition, as shown in FIG. 5A, the refractive index anisotropic medium 255a constituting the first phase difference plate 15a serves as the first vapor deposition film 1503a in the first predetermined direction, that is, the first vapor deposition direction. Is obliquely deposited on the first substrate 1501a. The first vapor deposition direction according to the present embodiment is a direction connecting 3 o'clock and 9 o'clock. Thus, the main refractive index nx ′ of the refractive index anisotropic medium 255a extends along the direction connecting 3 o'clock and 9 o'clock. The direction in this embodiment is expressed by the direction of the short hand of the timepiece. Specifically, the direction of 1:30 indicates the direction of the short hand when the timepiece placed on the plane of the first substrate or the second substrate in FIG. 5A indicates 1:30.

  In addition, in the refractive index anisotropic medium 255a, the optical axis corresponding to the main refractive index nx ′ of the refractive index anisotropic medium 255a has a first predetermined angle with respect to the plane direction of the first substrate 1501a, that is, the first Diagonal vapor deposition is performed to have a vapor deposition angle. This first deposition angle can be rephrased as a value obtained by subtracting the angle between the normal line of the substrate 1501a and the optical axis corresponding to the main refractive index nx 'of the refractive index anisotropic medium 255a from 90 degrees. Alternatively, this first vapor deposition angle can be rephrased as an angle between the optical axis corresponding to the main refractive index nx 'of the refractive index anisotropic medium 255a and the first vapor deposition direction.

  As shown in FIG. 5B, the refractive index anisotropic medium 255e constituting the second phase difference plate 15e serves as the second vapor deposition film 1503e along the second predetermined direction, that is, the second vapor deposition direction. It is obliquely deposited on the substrate 1501e. The second vapor deposition direction according to this embodiment is a direction connecting 0:00 and 6:00. As a result, the main refractive index nx ″ of the refractive index anisotropic medium 255e extends along the direction connecting 0 o'clock and 6 o'clock. In addition, in the refractive index anisotropic medium 255e, the optical axis corresponding to the main refractive index nx ″ of the refractive index anisotropic medium 255e has a second predetermined angle with respect to the plane direction of the second substrate 1501e, that is, the first Diagonal vapor deposition is performed to have two vapor deposition angles. In other words, the second deposition angle is a value obtained by subtracting the angle between the normal line of the first substrate 1501e and the optical axis corresponding to the main refractive index nx ″ of the refractive index anisotropic medium 255e from 90 degrees. Can do. Alternatively, this second vapor deposition angle can be restated as the angle between the optical axis corresponding to the main refractive index nx ″ of the refractive index anisotropic medium 255e and the second vapor deposition direction.

  As shown in FIG. 5C, the refractive index anisotropic that combines the refractive index anisotropic medium constituting the first phase difference plate 15a and the refractive index anisotropic medium that constitutes the second phase difference plate 15e. The main refractive index nx ′ ″ of the conductive medium 255ae extends along the direction connecting 4:30 and 10:30. This is because the main refractive index nx ′ of the refractive index anisotropic medium 255a extending along the direction connecting 3 o'clock and 9 o'clock described above and the direction connecting the above-described 0 o'clock and 6 o'clock. This is because the main refractive index nx ″ of the extending refractive index anisotropic medium 255e is synthesized.

  In addition, the direction in which the uniaxial optical axis of the refractive index anisotropic medium 255c formed by the vertical vapor deposition film 1501c constituting the first retardation plate 15a extends, that is, the direction of the main refractive index nzc ′ is the first This is the normal direction of the plane of the substrate 1501a or the first substrate 1501a.

  Specifically, the liquid crystal molecules 51 sealed in the liquid crystal panel 15c, the refractive index anisotropic medium 255a constituting the first retardation plate 15a, and the refractive index anisotropic medium 255e constituting the second retardation plate 15e. As shown in FIG. 6A, the first retardation plate 15a is viewed in plan view from the normal direction of the first substrate 1501a (or the second substrate 1501e), as shown in FIG. The direction in which the optical axis of the main refractive index nx ′ of the refractive index anisotropic medium 255a obliquely vapor-deposited on the substrate 1501a extends and the major axis direction of the liquid crystal molecules to which the pretilt is applied are, for example, an angle around 45 degrees. It is in a positional relationship that intersects. In addition, when viewed in plan from the normal direction of the second substrate 1501e (or the first substrate 1501a), the main refraction of the refractive index anisotropic medium 255e obliquely deposited on the substrate 1501e of the second retardation plate 15e. The direction in which the optical axis of the rate nx ″ extends and the major axis direction of the liquid crystal molecules to which the pretilt is applied are in a positional relationship that intersects at an angle of about 45 degrees, for example.

  In FIG. 6A, the major axis direction of the liquid crystal molecules provided with the pretilt is a so-called clear vision direction of 1:30. The major axis direction of the liquid crystal molecules means a direction in which the vertex of the axis closer to the light incident side of the two vertices of the major axis of the liquid crystal molecule faces.

  As shown in FIG. 6B, the optical axis of the main refractive index nx ′ of the refractive index anisotropy medium 255a when viewed from the vertical plane direction of the first substrate 1501a is the same as that of the first substrate 1501a. It intersects the plane at a first predetermined angle, that is, a first deposition angle (not shown). In addition, when viewed from a vertical plane direction of the second substrate 1501e, the optical axis of the main refractive index nx ″ of the refractive index anisotropic medium 255e is set at a second predetermined angle with the plane of the second substrate 1501e, That is, they intersect at the second deposition angle (shown). In other words, the optical axis of the main refractive index nx ′ of the refractive index anisotropic medium 255a and the optical axis of the main refractive index nx ″ of the refractive index anisotropic medium 255e may have a twisted positional relationship. Alternatively, the optical axis of the main refractive index nx ′ of the refractive index anisotropic medium 255a and the major axis direction of the liquid crystal molecules may be in a twisted positional relationship. Alternatively, the optical axis of the main refractive index nx ″ of the refractive index anisotropic medium 255e may be in a twisted positional relationship with the major axis direction of the liquid crystal molecules. The first deposition angle or the second deposition angle may be smaller than an angle obtained by subtracting the pretilt angle of the liquid crystal molecules from 90 degrees.

  Thereby, the direction in which the optical axis of the first retardation plate 15a, that is, the optical axis of the main refractive index nx ′ of the refractive index anisotropic medium 255a extends is in the major axis direction of the liquid crystal molecules 51 inclined by the pretilt angle. Therefore, the optical axis of the first retardation plate 15a compensates for the optical anisotropy of the liquid crystal molecules 51 toward optical isotropy in the plane direction and the vertical plane direction of the first substrate 1501a.

  In addition, the direction in which the optical axis of the second retardation plate 15e, ie, the optical axis of the main refractive index nx ″ of the refractive index anisotropic medium 255e extends, is the long axis direction of the liquid crystal molecules 51 inclined by the pretilt angle. Therefore, in the plane direction and the vertical plane direction of the second substrate 1501e, the optical axis of the second retardation plate 15e compensates for the optical anisotropy of the liquid crystal molecules 51 to be optically isotropic. .

  More specifically, as shown in FIG. 7, the major axis of the refractive index ellipsoid formed by the liquid crystal molecules 51, the refractive index anisotropic medium constituting the first retardation plate 15a, and the second retardation. Since the major axis of the refractive index ellipsoid formed by the refractive index anisotropic medium 255ae synthesized with the refractive index anisotropic medium constituting the plate 15e intersects, the liquid crystal molecules and the first and second retardation plates The refractive index ellipsoid formed by and can be approximated to the refractive index sphere in three dimensions. A so-called O plate is formed by a refractive index anisotropic medium 255ae obtained by synthesizing a refractive index anisotropic medium constituting the first retardation plate 15a and a refractive index anisotropic medium constituting the second retardation plate 15e. Note that is approximately realized.

  In addition, the uniaxial optical axis (that is, one specific example of the uniaxial optical axis according to the present invention) of the vertical vapor deposition film 1501c constituting the first retardation plate 15a described above, in other words, the refractive index anisotropy. The direction in which the optical axis of the main refractive index nxc ′ (or main refractive index nyc ′) of the medium 255c extends, that is, the plane direction of the vertical deposition film 1501c intersects the long axis direction of the liquid crystal molecules 51 inclined by the pretilt angle. As a result, the refractive index ellipsoid formed by the four elements of the liquid crystal molecules 51, the vertical vapor deposition film 1501c, the first vapor deposition film 1503a, and the second vapor deposition film 1503e can be brought close to the refractive index sphere three-dimensionally. it can.

  Therefore, the phase difference (in other words, birefringence effect) generated in the liquid crystal by the first phase difference plate 15a and the second phase difference plate 15e can be canceled (ie, compensated). As a result, during the operation of the projector, the phase difference of the light generated when the light emitted from the light source passes through the liquid crystal composed of liquid crystal molecules tilted by, for example, the pretilt angle is calculated as the first retardation plate 15a and the first retardation plate 15a. It can be compensated by the two phase difference plate 15e. Therefore, it is possible to prevent the light that has passed through the liquid crystal panel from entering the output-side polarizing plate in a phase-shifted state. As a result, for example, in the polarizing plate on the output side, the possibility that light that should not be allowed to leak is reduced, and it is possible to prevent a decrease in contrast and a reduction in viewing angle.

  Here, if the liquid crystal light valve 15 is not provided with the first retardation plate 15a and the second retardation plate 15e, the liquid crystal layer 34 sealed in the liquid crystal panel 15c is optically uniaxial. The refractive index in the director direction of the liquid crystal molecules 51 is larger than the refractive index in the other direction. That is, the liquid crystal layer 34 has a rugby ball-type refractive index ellipsoid as shown in the above-described average refractive index ellipsoid 250a in FIG. Here, the liquid crystal molecules 51 of the liquid crystal layer 34 are obliquely aligned along the pretilt direction P, cause a residual phase difference during black display, and differ in the elliptical shape when observed from the oblique direction. With a dependent phase difference. This phase difference causes light leakage in black display, and reduces the contrast ratio of the liquid crystal panel.

  Alternatively, for example, a retardation plate whose optical axis direction is along the thickness direction, such as a C plate or a retardation plate having uniaxial refractive index anisotropy, is used, and the retardation plate is inclined. When the optical anisotropy of liquid crystal molecules is compensated by the above, the space for inclining the retardation plate is limited inside the projector, for example, from the viewpoint of the cooling effect due to the circulation of air. It becomes technically difficult to appropriately prevent the decrease. Or the mechanism which inclines this phase difference plate will become complicated, and the adjustment which inclines a phase difference plate will become technically difficult in an assembly process.

  However, in the present embodiment, in particular, as described above, the optical axis of the first retardation plate 15a compensates for the optical anisotropy of the liquid crystal molecules 51 by vapor deposition of the refractive index anisotropic medium 255a. The first substrate 1501a intersects the first predetermined direction, so-called first deposition direction, at a first predetermined angle, so-called first deposition angle. Therefore, the optical anisotropy of the liquid crystal molecules 51 of the liquid crystal panel is adjusted by adjusting the first vapor deposition direction and the first vapor deposition angle in which the refractive index anisotropic medium 255a constituting the first retardation plate 15a is vapor-deposited. Can be easily and highly accurately compensated.

  In addition, as described above, the optical axis of the second retardation plate 15e is adjusted in the second predetermined direction so as to compensate for the optical anisotropy of the liquid crystal molecules 51 by vapor deposition of the refractive index anisotropic medium 255e. In the so-called second deposition direction, the second substrate 1501e intersects with a second predetermined angle, so-called second deposition angle. Accordingly, the optical anisotropy of the liquid crystal molecules 51 of the liquid crystal panel is adjusted by adjusting the second vapor deposition direction and the second vapor deposition angle in which the refractive index anisotropic medium 255e constituting the second retardation plate 15e is vapor-deposited. Can be easily and highly accurately compensated.

  In addition, as described above, the short axis and the long axis of the vertical vapor deposition film 1501c constituting the first retardation plate 15a are arranged so that the optical anisotropy of the liquid crystal molecules 51 is compensated for by the substrate. Vertical deposition is performed on 1501a. Therefore, the optical anisotropy of the liquid crystal molecules 51 of the liquid crystal panel can be easily and accurately adjusted by adjusting the main refractive index of the uniaxial optical axis of the vertical vapor deposition film 1501c constituting the first retardation film 15a. Can be compensated.

  In particular, the above-described three types of refractive index anisotropic mediums, ie, the refractive index anisotropic medium 255c, the refractive index anisotropic medium 255a, and the refractive index anisotropic medium 255e, are individually connected to the optical liquid crystal molecules. By compensating for anisotropy, the compensation effect can be significantly improved. Typically, the three parameters described above, ie, the main refractive index of the uniaxial optical axis in the refractive index anisotropic medium 255c, the first deposition direction and the first deposition angle in the refractive index anisotropic medium 255a, and By adjusting more physical quantities such as the second vapor deposition direction and the second vapor deposition angle in the refractive index anisotropic medium 255e, the optical anisotropy of the liquid crystal molecules can be compensated with higher accuracy.

  Further, in order to compensate for the optical anisotropy of the liquid crystal molecules 51 of the liquid crystal panel, there is little or no need to tilt the first retardation plate 15a and the second retardation plate 15e. The adjustment step for inclining the first retardation plate 15a and the second retardation plate 15e can be omitted, and the optical anisotropy of the liquid crystal molecules can be compensated and the contrast can be increased easily and at low cost. . As a result, according to the projector according to the present embodiment, the effect of compensating the phase difference generated in the liquid crystal by the first phase difference plate 15a and the second phase difference plate 15e can be increased, and the contrast can be increased. .

  As described above, according to the projector according to the present embodiment, (i) the first vapor deposition direction and the first vapor deposition angle in which the refractive index anisotropic medium 255a constituting the first retardation plate 15a is obliquely vapor-deposited. (Ii) adjusting the second deposition direction and the second deposition angle in which the refractive index anisotropic medium 255e constituting the second retardation plate 15e is obliquely deposited, and (iii) the first position At least one of the adjustment of the main refractive index of the uniaxial optical axis of the refractive index anisotropic medium 255c constituting the phase difference plate 15a is performed. Thereby, the phase difference which arises in a liquid crystal can be compensated reliably by the 1st phase difference plate 15a and the 2nd phase difference plate 15e. As a result, a high-contrast and high-quality display can be obtained.

  In particular, the first vapor deposition direction and the first vapor deposition angle in which the refractive index anisotropic medium constituting the first retardation plate 15a is obliquely vapor-deposited, and the refractive index anisotropic medium constituting the second retardation plate 15e are provided. By adjusting the second vapor deposition direction and the second vapor deposition angle to be obliquely deposited so as to sandwich the major axis direction of the liquid crystal molecules 51 inclined by the pretilt angle, the optical anisotropy of the liquid crystal molecules 51 is increased. It is possible to compensate more appropriately toward optical isotropy, and to obtain a display with higher contrast and higher quality. According to the research by the inventors of the present application, it has been found that the contrast can be further increased by setting the angle formed by the first vapor deposition direction and the second vapor deposition direction to be within a range from about 70 degrees to about 110 degrees. ing. In addition, as will be described later, the first retardation plate 15a is rotated about the normal direction of the first retardation plate 15a as the rotation axis, and the second retardation plate 15e is rotated with respect to the second retardation plate 15e. By rotating about the normal direction as the rotation axis, higher contrast can be obtained in the relative positional relationship between the major axis direction of the liquid crystal molecules 51 inclined by the pretilt angle, the first deposition direction, and the second deposition direction. Thus, it can adjust with higher precision. Specifically, in addition to the four parameters described above, that is, the four physical quantities of the first deposition direction, the first deposition angle, the second deposition direction, and the second deposition angle, the major axis direction of the tilted liquid crystal molecules 51 and By adjusting the angle between the first vapor deposition direction and the angle between the major axis direction of the inclined liquid crystal molecules 51 and the second vapor deposition direction, the optical parameters of the liquid crystal molecules 51 can be adjusted by adjusting more parameters. It is possible to compensate for anisotropy with higher accuracy.

  In particular, the use of an inorganic material such as Ta2O5 as the vapor deposition film on which the refractive index anisotropic medium is obliquely vapor-deposited is caused by the first retardation plate 15a or the second retardation due to light irradiation and the accompanying temperature rise. It is possible to effectively prevent the plate 15e from being deteriorated, and it is possible to configure a projector having excellent reliability.

(Quantitative analysis of contrast improvement due to film thickness of first and second retardation plates)
Next, with reference to FIG. 8, a quantitative analysis of contrast improvement due to the film thicknesses of the first and second retardation plates according to the present embodiment will be described. FIG. 8 is a bar graph showing the relationship between the film thicknesses of the first and second retardation plates according to this embodiment and the combination of the first and second retardation plates (FIG. 8 ( a)), and a graph quantitatively showing the correlation between the film thickness of the first and second retardation plates according to the present embodiment and the contrast of light (FIG. 8B). In FIG. 8A, the horizontal axis indicates the combination of the first retardation plate and the second retardation plate, and the vertical axis indicates the film thickness of the first and second retardation plates. The horizontal axis of FIG.8 (b) shows the combination of a 1st phase difference plate and a 2nd phase difference plate, and a vertical axis | shaft shows the magnitude | size of contrast.

  In particular, the refractive index in the thickness direction of the first retardation plate includes the above-described main refractive indexes nx ′, ny ′, nz ′, the first deposition angle, and the refractive index anisotropic medium 255a constituting the first retardation plate. It can be uniquely defined by the material. In substantially the same manner, the refractive index in the thickness direction of the second retardation plate is the main refractive index nx ″, ny ″, nz ″, the second vapor deposition angle, and the refraction constituting the second retardation plate. It can be uniquely defined by the material of the rate anisotropic medium 255e.

  As shown in FIG. 8B, the ratio between the thickness of the first phase difference plate and the thickness of the second phase difference plate between 0.3 μm and 0.6 μm is large level and medium level. When the sampling sets S1, S2 and S3 which are small levels are compared, the ratio of the variation of the thickness of the first retardation plate and the thickness of the second retardation plate is between 0.3 μm and 0.6 μm In the sampling set S1 where is a large level, the contrast exceeds 5000 and it has been found that higher contrast can be realized.

  Specifically, as shown in FIG. 8A, the ratio of the thickness of the first retardation plate and the thickness of the second retardation plate is between 0.3 μm and 0.6 μm. The sampling set S1 which is a large level represents a combination of the sample X corresponding to the first phase difference plate and the sample Y corresponding to the second phase difference plate as (sample X, sample Y) These are composed of the following six combinations. That is, the sampling set S1 includes (Sample A, Sample B), (Sample B, Sample C), (Sample B, Sample D), (Sample A, Sample D), (Sample C, Sample D), (Sample A, sample C). Sample A has a thickness of 0.55 μm, sample B has a thickness of 0.45 μm, sample C has a thickness of 0.40 μm, and sample D has a thickness of 0.30 μm.

  In substantially the same manner, the sampling set S2 in which the variation of the thickness of the first retardation plate and the thickness of the second retardation plate is at a medium level between 0.3 μm and 0.6 μm is as follows. It is composed of eight combinations. (Sample D, Sample E), (Sample D, Sample F), (Sample A, Sample G), (Sample A, Sample E), (Sample C, Sample E), (Sample D, Sample G), (Sample A, Sample F) and (Sample C, Sample F). Sample E has a thickness of 0.60 μm, sample F has a thickness of 0.20 μm, and sample G has a thickness of 0.70 μm.

  In substantially the same manner, the sampling set S3 in which the variation in the thickness of the first retardation plate and the thickness of the second retardation plate is between 0.3 μm and 0.6 μm is a small level, It is composed of seven combinations. (Sample G, Sample H), (Sample A, Sample H), (Sample B, Sample H), (Sample D, Sample H), (Sample C, Sample H), (Sample F, Sample H) and (Sample E, Sample H). Sample H has a thickness of 0.85 μm.

  As a result, the contrast tends to increase as the ratio of the thickness of the first retardation plate and the thickness of the second retardation plate between 0.3 μm and 0.6 μm increases. I understand that.

(Quantitative analysis of phase difference change due to film thickness and deposition angle of first and second retardation plates)
Next, with reference to FIG. 9 and FIG. 10, the film thicknesses of the first and second phase difference plates and the first refractive index anisotropic medium constituting the first and second phase difference plates according to the present embodiment. The quantitative analysis of the phase difference change caused by the second deposition angle will be described. FIG. 9 is a graph quantitatively showing the correlation between the vapor deposition angle and the contrast of the refractive index anisotropic medium constituting the first and second retardation plates according to this embodiment with respect to the first substrate. is there. In addition, the vertical axis | shaft of FIG. 9 shows the magnitude | size of contrast, and a horizontal axis shows a vapor deposition angle. FIG. 10 shows the first and second phase differences when the film thicknesses of the first and second phase difference plates and the vapor deposition angle of the refractive index anisotropic medium constituting the phase difference plate are used as variables. 11 is a graph (FIGS. 10A and 10B) that quantitatively shows the correlation between the angle and the polar angle. 10A corresponds to the case where the film thickness is 0.5 μm, and FIG. 10B corresponds to the case where the film thickness is 0.8 μm. In FIGS. 10 (a) and 10 (b), the solid curve indicates the change in phase difference when the deposition angle is 50 degrees, and the alternate long and short dash line curve indicates the position when the deposition angle is 57 degrees. The change of the phase difference is shown, and the dotted curve shows the change of the phase difference when the deposition angle is 64 degrees. Further, although the unit of the phase difference is shown as “nm (nanometer)”, it can be displayed as radians by dividing this nm by the wavelength of light and integrating 360 degrees. In addition, about the quantitative property of the phase difference change resulting from the film thickness and vapor deposition angle in a 1st phase difference plate and a 2nd phase difference plate, since it is substantially the same, the 1st phase difference plate is demonstrated for convenience of explanation.

  According to the research by the present inventor, as shown in FIG. 9 as an example of statistical analysis, in order to make the contrast larger than 120,000, the refractive index anisotropic that constitutes the first retardation plate It has been found that the first deposition angle of the conductive medium with respect to the first substrate is preferably in the range between 50 degrees and 70 degrees. As described above, the first deposition angle corresponds to the main refractive index nx ′ of the refractive index anisotropic medium 255a when the refractive index anisotropic medium 255a is obliquely deposited on the first substrate 1501a. It means the angle between the optical axis and the plane direction of the first substrate 1501a. This first deposition angle can be rephrased as a value obtained by subtracting the angle between the normal line of the first substrate 1501a and the optical axis corresponding to the main refractive index nx ′ of the refractive index anisotropic medium 255a from 90 degrees. it can. Alternatively, the first vapor deposition angle is determined by obliquely vapor-depositing the optical axis corresponding to the main refractive index nx ′ of the refractive index anisotropic medium 255a and the refractive index anisotropic medium 255a on the first substrate 1501a. In other words, it can be said to be an angle between the deposition direction.

  Further, as shown in FIG. 10A, the polar angle indicating the angle of line of sight when the film thickness is 0.5 μm when viewed from the front of the liquid crystal light valve 15 is 0 degree is minus. As the angle is changed from 50 degrees to plus 50 degrees, the phase difference generated by the first phase difference plate 15a can be changed from around 40 nm (nanometer) to 0 nm. Specifically, as shown by the solid curve in FIG. 10A, when the first deposition angle is 50 degrees, the phase difference when the polar angle is zero, the so-called front phase difference is around 15 nm. I know that there is. It can also be seen that the phase difference is zero when the polar angle is around 30 degrees. Moreover, as shown by the dashed-dotted curve in FIG. 10A, it can be seen that the front phase difference is around 20 nm when the first deposition angle is 57 degrees. It can also be seen that the phase difference is zero when the polar angle is around 40 degrees. Also, as shown by the dotted curve in FIG. 10A, it can be seen that the front phase difference is around 25 nm when the first deposition angle is 64 degrees. It can also be seen that the phase difference is zero when the polar angle is around 50 degrees.

  In substantially the same manner, as shown in FIG. 10B, it is generated by the first retardation plate 15a as the polar angle is changed from minus 50 degrees to plus 50 degrees under the condition that the film thickness is 0.8 μm. The phase difference can be changed from around 65 nm to 0 nm. Specifically, as shown by the solid curve in FIG. 10B, it can be seen that the front phase difference is around 25 nm when the first deposition angle is 50 degrees. It can also be seen that the phase difference is zero when the polar angle is around 30 degrees. Further, as shown by the dashed line curve in FIG. 10B, it is understood that the front phase difference is around 35 nm when the first deposition angle is 57 degrees. It can also be seen that the phase difference is zero when the polar angle is around 40 degrees. Further, as shown by the dotted curve in FIG. 10B, it can be seen that the front phase difference is around 40 nm when the first deposition angle is 64 degrees. It can also be seen that the phase difference is zero when the polar angle is around 50 degrees.

In this way, by changing the film thickness of the first retardation plate and the first deposition angle of the refractive index anisotropic medium constituting the first retardation plate from about 50 degrees to about 70 degrees, for example, the front position The phase difference generated by the first phase difference plate 15a such as a phase difference can be controlled with high accuracy. Accordingly, in the process of incorporating the liquid crystal light valve 15 according to the present embodiment into the projector, the achievable contrast is set with high accuracy by rotating the first retardation plate 15a about the incident direction in which light is incident. In this case, the rotation angle of the first retardation plate 15a can be limited to be within a predetermined range. Accordingly, since the first retardation plate 15a is rotated within a limited predetermined range, the contrast can be adjusted more easily.
(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS. FIG. 11 is a schematic configuration diagram of a liquid crystal projector according to the second embodiment of the present invention. In FIG. 11, components that are substantially the same as those in the first embodiment described above are denoted by the same reference numerals, and description thereof will be omitted as appropriate. FIG. 12 is a graph showing the correlation between the type of phase difference plate, the phase difference, and the polar angle in the phase difference plate according to the second embodiment of the present invention. As described above, the polar angle indicates the angle of the line of sight when viewed from the front of the liquid crystal light valve 15 as 0 degree. FIG. 13 is a graph showing the correlation between the type of the retardation plate and the contrast in the retardation plate according to the second embodiment of the present invention. 13 corresponds to the case where the pretilt angle of the liquid crystal molecules is 5 degrees, and the white bar graph in FIG. 13 corresponds to the case where the pretilt angle of the liquid crystal molecules is 4 degrees. To do. FIG. 14 is a diagram showing an optical axis arrangement of each component in FIG.

  As shown in FIG. 11, the liquid crystal projector according to the second embodiment includes a first phase difference plate 15a1 and a third phase difference plate 15a1 instead of the first phase difference plate 15a of the liquid crystal projector according to the first embodiment described above. A phase difference plate 15f is provided. The third retardation plate 15f may be configured by vertical vapor deposition of the refractive index anisotropic medium 255c, or may be configured by an optical film. Further, the first retardation plate 15a1 constitutes another specific example of the first retardation plate according to the present invention. Further, the third retardation plate 15f constitutes one specific example of the third retardation plate according to the present invention.

  The first retardation plate 15a1 includes (i) a first substrate 1501a, (ii) a first vapor deposition film 1503a on which a refractive index anisotropic medium that retains the first refractive index anisotropy is obliquely vapor deposited, iii) A third substrate 1502a is provided. On the side of the first retardation plate 15a1 in FIG. 11, the main refractive index in the optical axis direction of the refractive index ellipsoid of the refractive index anisotropic medium 255a is shown. In the present embodiment, the main refractive indexes nx ′, ny ′, and nz ′ are configured to satisfy the relationship of nx ′> ny ′> nz ′. That is, the refractive index nx 'in the direction inclined from the normal direction of the first substrate 1501a or the second substrate 1502 is larger than the refractive indexes ny' and nz 'in the other directions, and the refractive index ellipsoid has a rice grain shape. Specifically, a biaxial plate can be given as a typical example of the refractive index anisotropic medium 255a.

  As described above, the second retardation plate 15e includes (i) the second substrate 1501e and (ii) the second vapor deposition film 1503e on which the refractive index anisotropic medium 255e holding the refractive index anisotropy is obliquely deposited. And (iii) a fourth substrate 1502e.

  An average refractive index ellipsoid 255c of the third retardation plate 15f is schematically shown on the side of the third retardation plate 15f in FIG. In this figure, nxc ′ and nyc ′ indicate the main refractive index in the surface direction of the third phase difference plate 15f, and nzc ′ indicates the main refractive index in the thickness direction of the third phase difference plate 15f. . In this embodiment, the main refractive indexes nxc ′, nyc ′, and nzc ′ are configured to satisfy the relationship nxc ′ = nyc ′> nzc ′. That is, the refractive index nzc 'in the thickness direction is smaller than the refractive index in the other direction, and the refractive index ellipsoid is a disk shape. The refractive index ellipsoid 255c is oriented parallel to the plate surface of the third retardation plate 15f, and the optical axis direction (the minor axis direction of the refractive index ellipsoid) of the third retardation plate 15f is the plate surface. Parallel to the normal direction. Specifically, a negative C plate can be used as the third retardation plate 15f, and in this embodiment, a C plate using a discotic liquid crystal is used. For example, an optical film using a non-stretched triacetyl cellulose (TAC), a non-stretched cellulose acetate propionate (CAP) or the like, a biaxially stretched norbornene resin, or the like can also be used.

  In particular, as the third retardation plate 15f, typically, a refractive index anisotropic medium having a relatively high refractive index and a refractive index anisotropic medium having a relatively low refractive index are alternately stacked. You may employ | adopt C plate comprised with the vapor deposition film which performed. By changing the thickness of the deposited films thus laminated, it is possible to realize changes in light characteristics such as a change in the light traveling direction, a change in the polarization state, and a change in frequency and phase.

  Specifically, the third retardation plate 15f preferably has a phase difference of about 10 to 20 (nm: nanometer) when the polar angle is 30 degrees. Thereby, contrast can be made higher. It should be noted that there is a slight tolerance in the width of the phase difference depending on the wavelength of light. Specifically, as shown in FIG. 12, the third retardation plate 15 f has NR10 and 20 (nm) where the phase difference value is 10 (nm) when the polar angle is 30 degrees. NR20, NR30 which is 30 (nm), NR35 which is 35 (nm), NR40 which is 40 (nm), NR60 which is 60 (nm), and NR90 which is 90 (nm). As shown in FIG. 13, it has been found that the use of NR10, NR15, and NR20 as the type of the third retardation plate 15f is preferable from the viewpoint of increasing the contrast. Specifically, when the pretilt angle of the liquid crystal molecules is 4 degrees, the contrast can be made larger than 1600 when NR10, NR15, and NR20 are adopted as the type of the third retardation plate 15f. Further, when the pretilt angle of the liquid crystal molecules is 5 degrees, when NR10, NR15, and NR20 are adopted as the type of the third retardation plate 15f, the contrast can be made larger than 1300.

  As described above, the liquid crystal projector according to the second embodiment includes the first retardation plate 15a1 and the third retardation plate 15f instead of the first retardation plate 15a of the liquid crystal projector according to the first embodiment. It is prepared for. Accordingly, the first retardation plate 15a1, the second retardation plate 15e, and the third retardation plate 15f are arranged at different optical positions, or at least of the first to third retardation plates. Since one can be temporarily removed, optical adjustment can be easily performed. In addition, since the manufacturing method and material of the first to third retardation plates can be varied, optical adjustment can be performed at a lower cost. In addition, when the C plate is used as the phase difference plate 15e, the diffraction phenomenon and the focal position are close to the standard value for a panel with MLA and a projector with a small F value on the incident side. However, the contrast can be further increased.

  Specifically, as shown in FIG. 14, the optical adjustment of the liquid crystal light valve 15 in the projector according to the second embodiment is provided so as to be movable around an axis whose rotation axis is the substrate normal of the liquid crystal panel 15c. In addition to or instead of the first optical adjustment step for adjusting the rotation angle of the first retardation plate 15a1, the second position is provided so as to be movable around an axis whose axis is the substrate normal of the liquid crystal panel 15c. This can be performed by the second optical adjustment step for adjusting the rotation angle of the phase difference plate 15e. The details of the first optical adjustment step and the second optical adjustment step will be described later.

(Quantitative analysis of contrast improvement due to rotation of first to third retardation plates)
Next, referring to FIG. 14 or FIG. 4 as appropriate in addition to FIG. 15 and FIG. 16, the contrast is caused by the rotation of the first to third retardation plates with the substrate normal as the rotation axis. The improvement will be described. FIG. 15 is a bar graph quantitatively showing the correlation between the contrast realized by the first to third phase difference plates according to the present embodiment and the contrast realized by the phase difference plate according to the comparative example. It is. FIG. 16 is a distribution diagram (FIG. 16A and FIG. 16B) showing the variation in luminance in the liquid crystal panel to which the phase difference plate according to this embodiment and the comparative example is applied.

  The optical adjustment of the liquid crystal light valve 15 in the projector according to the present embodiment is performed by adjusting the rotation angle of the first retardation plate 15a1 provided so as to be movable around an axis whose rotation axis is the substrate normal line of the liquid crystal panel 15c. In addition to or instead of the one optical adjustment step, by the second optical adjustment step for adjusting the rotation angle of the second retardation plate 15e provided so as to be movable around an axis whose rotation axis is the substrate normal line of the liquid crystal panel 15c. Can be implemented.

  In the first optical adjustment step, as shown in FIG. 14 described above, the rotation axis 81a of the first retardation plate 15a1 disposed to face the liquid crystal panel 15c is moved to the first retardation plate 15a1 (and the liquid crystal panel 15c). ) In the direction along the normal direction. Then, by rotating the first phase difference plate 15a1 around the rotation axis 81a and adjusting the rotation angle θa, the optical axis of the first phase difference plate 15a1 described above, that is, the anisotropic refractive index. The angle between the direction of the optical axis of the main refractive index nx ′ of the crystalline medium 255a and the major axis direction of the liquid crystal molecules 51 inclined by the pretilt angle is adjusted with high accuracy. In addition to or instead of this, the rotation axis 81e of the second retardation plate 15e disposed facing the liquid crystal panel 15c is aligned with the normal direction of the second retardation plate 15e (and the liquid crystal panel 15c). Set the direction. Then, by rotating the second phase difference plate 15e around the rotation axis 81e and adjusting the rotation angle θe, the optical axis of the second phase difference plate 15e described above, that is, the anisotropic refractive index. The angle between the direction of the optical axis of the main refractive index nx ″ of the conductive medium 255e and the major axis direction of the liquid crystal molecules 51 inclined by the pretilt angle is adjusted with high accuracy.

  Specifically, as described above, the five parameters, that is, the main refractive index of the uniaxial optical axis of the third retardation plate 15f, the first deposition direction, the first deposition angle, the second deposition direction, and the second deposition. In addition to the five physical quantities called angles, the rotation angle θa corresponding to the angle between the major axis direction of the tilted liquid crystal molecules 51 and the first deposition direction, and the major axis direction of the tilted liquid crystal molecules 51 and the second By adjusting the rotation angle θe corresponding to the angle with the deposition direction, the optical anisotropy of the liquid crystal molecules 51 can be compensated with higher accuracy by adjusting more parameters.

  As a result, the refractive index ellipsoid formed by the liquid crystal molecules and the first to third retardation plates can be made closer to the refractive index sphere, and a desired contrast can be obtained.

  Specifically, as shown in FIG. 15, according to the projector according to the present embodiment, when the first retardation plate 15 a 1, the second retardation plate 15 e to the third retardation plate 15 f are used, the contrast is high. It can exceed 2750, and a higher contrast can be easily realized as compared with the comparative example. Specifically, according to the projector according to the present embodiment, for example, a projector using a retardation plate made of an optical cell cell material according to a comparative example, a projector using a uniaxial retardation plate such as an optical film, A projector or the like in which a retardation plate having an optical axis direction along the thickness direction such as a C plate is inclined by 2 ° to 4 ° and 12 ° has a contrast smaller than 2500. On the other hand, according to the present embodiment, the first phase difference plate 15a1, the second phase difference plate 15e, and the third phase difference plate 15f are tilted around the rotation axis 81a without tilting. In addition to or in place of adjusting the rotation angle θa by rotating the first phase difference plate 15a1, the rotation angle θe is adjusted by rotating the second phase difference plate 15e around the rotation axis 81e. As a result, the angle between the optical axis direction of the first retardation plate 15a1 and the major axis direction of the liquid crystal molecules 51 inclined by the pretilt angle is adjusted with high accuracy, and the desired contrast is simple. The angle between the direction of the optical axis of the second retardation plate 15e and the major axis direction of the liquid crystal molecules 51 inclined by the pretilt angle can be adjusted with high accuracy. The desired contrast can be obtained by simple adjustment. In this embodiment, the first and second retardation plates need not be inclined in the space between the liquid crystal panel and the first and second retardation plates, so that the air circulation is not hindered. Therefore, it is possible to minimize heat accumulation between the liquid crystal panel 15c and the first and second retardation plates, which is also effective in suppressing deterioration of the liquid crystal panel and the retardation plate. .

  In addition, as shown in FIG. 16B, according to the present embodiment, brightness variation, so-called brightness unevenness, is shown inside a white dotted line circle indicating that the polar angle is about 30 degrees in the liquid crystal panel. Can be effectively prevented from occurring. Specifically, in the lower left corner of the white dotted line circle indicating that the polar angle is about 30 degrees in the liquid crystal panel according to the comparative example shown in FIG. It can be seen that uneven brightness occurs. In FIG. 16A, due to the major axis direction of the liquid crystal molecules 51 tilted by the pretilt angle, the luminance unevenness in the liquid crystal panel occurs symmetrically with the major axis of the liquid crystal molecules 51 as the symmetry axis. You can see that On the other hand, according to the projector according to the present embodiment, the direction in which the optical axis of the first retardation plate 15a1, that is, the optical axis of the main refractive index nx ′ of the refractive index anisotropic medium 255a extends is pretilt. The liquid crystal molecules 51 tilted by an angle intersect with the major axis direction at one angle, and the optical axis of the second retardation plate 15e, that is, the optical axis of the main refractive index nx ″ of the refractive index anisotropic medium 255e extends. The direction intersects with the major axis direction of the liquid crystal molecules 51 inclined by a pretilt angle at another angle. In addition, there are main refractive indexes nxc ′ and nyc ′ of the optical axis of the refractive index ellipsoid 255c in the plane direction of the third retardation plate 15f.

  As a result, the occurrence of luminance unevenness is canceled out by the optical axis of the first retardation plate 15a, the optical axis of the second retardation plate 15e, and the optical axis of the third retardation plate 15f. It has been found that generation can be effectively prevented.

  In particular, when a biaxial plate is adopted as a typical example of the above-described refractive index anisotropic medium 255a, the main refractive indexes nx ′, ny ′, and nz ′ satisfy the relationship nx ′> ny ′> nz ′. As shown in FIG. 14 described above, the rotation angle θa is adjusted by rotating the first phase difference plate 15a1 about the rotation axis 81a extending in the normal direction of the substrate. In addition to or instead of this, when a biaxial plate is adopted as a typical example of the above-described refractive index anisotropic medium 255e, the main refractive indexes nx ″, ny ″, nz ″ are nx ″. Since> ny ''> nz '' is satisfied, as shown in FIG. 14 described above, the second retardation plate 15e is rotated about an axis centering on the rotation axis 81e extending in the normal direction of the substrate. Adjust the rotation angle θe.

  Accordingly, the positional relationship between the optical axes of the first and second retardation plates 15a1 and 15e and the optical axes of the polarizing plates 15b and 15d and the liquid crystal panel 15c is changed to correspond to the first and second positions. The positions of the phase difference plates 15a1 and 15e can be optimized. Specifically, by rotating the first or second retardation plates 15a1 and 15e, the positional relationship between the first and second retardation plates 15a1 and 15e and the first and second polarizing plates 15b and 15d is determined. For example, the main refractive indexes nx, ny, and nz of the A plate can be configured to have components that satisfy the relationship of nx = ny> nz, so that the first and second polarizing plates 15b and 15d The phase difference caused by the phase difference or the diffraction effect of the microlens 95 can be compensated. In particular, in addition to the rotation adjustment of the first and second retardation plates 15a1 and 15e, by adjusting the front phase difference of the first and second retardation plates 15a1 and 15e, the first and second polarizing plates 15b. , 15d and the phase difference caused by the diffraction effect of the microlens 95 can be more effectively compensated.

  A specific example of the “optical adjustment step” according to the present invention is configured by rotating the first retardation plate 15a1 (or 15a) with the normal direction described above as the rotation axis 81a. Further, another specific example of the “optical adjustment step” according to the present invention is configured by rotating the second retardation plate 15e with the normal direction described above as the rotation axis 81e.

  Further, as described above, the first phase difference plate 15a1 generates the first phase difference plate 15a1 by changing the film thickness of the first phase difference plate 15a1 and the first deposition angle of the refractive index anisotropic medium constituting the first phase difference plate 15a1. In the process of incorporating the liquid crystal light valve 15 according to the present embodiment into the projector, the first phase difference plate 15a1 is rotated about the incident direction in which light is incident as a rotation axis. When the realizable contrast is set with high accuracy, the rotation angle of the first phase difference plate 15a1 can be limited to be within a predetermined range (for example, a range of ± 5 degrees). Therefore, since the first retardation plate 15a1 is rotated within a limited predetermined range, the maximum contrast in terms of the function of the projector can be adjusted more easily.

  In substantially the same manner, by changing the film thickness of the second retardation plate and the second deposition angle of the refractive index anisotropic medium constituting the second retardation plate as described above, the second retardation plate 15e By changing the generated front phase difference more greatly, in the step of incorporating the liquid crystal light valve 15 according to the present embodiment into the projector, the second phase difference plate 15e is rotated about the incident direction in which light is incident as the rotation axis. Thus, the rotation angle of the second retardation plate 15e when setting the realizable contrast with high accuracy can be limited to be within a predetermined range (for example, a range of ± 5 degrees). Therefore, since the second phase difference plate 15e is rotated within a limited predetermined range, the maximum contrast in terms of the function of the projector can be adjusted more easily. In particular, the adjustment of the rotation angle of the first phase difference plate 15a1 and the adjustment of the rotation angle of the second phase difference plate 15e may be performed at the same time in consideration of the influence on the contrast between them. You can go.

  The optical adjustment of the first retardation plate 15a1 and the optical adjustment of the second retardation plate 15e are preferably performed while actually measuring the contrast (or the luminance of black display). In general, the optical axis in the plane direction of the protective film 152 of the polarizing plate is not set in a fixed direction, and the optical axis may vary within the plane even with the same polarizing plate. For this reason, the rotation angle θa of the first phase difference plate 15a1 and the rotation angle θe of the second phase difference plate 15e cannot be set to constant angles, so that the position where the maximum contrast is actually obtained or the black level is the lowest. It is preferable that the position at which the first phase difference plate 15a and the second phase difference plate 15e are optimal. In addition, in FIG. 14 described above, the contrast can be further increased by rotating the polarizing plate about the normal direction described above as the rotation axis.

  In general, when a retardation plate is formed by oblique vapor deposition, there is a possibility that an axial deviation in which the optical axis deviates from a desired vapor deposition angle or vapor deposition direction may occur. In particular, in this embodiment, optical adjustment is performed by rotating two types of phase difference plates that are obliquely vapor-deposited to perform optical adjustment by rotating one type of phase difference plate or an integrated phase difference plate. It is possible to suppress the influence due to the axis deviation than when performing. Thereby, the dispersion | variation in the optical characteristic on manufacture in a phase difference plate can be compensated.

(Arrangement of first to third retardation plates)
Next, the arrangement of the first and second retardation plates according to the present embodiment will be described with reference to FIGS. FIG. 17 is a schematic diagram (FIG. 17 (a) to FIG. 17 (i)) showing the arrangement of the constituent members in the liquid crystal light valve 15 according to this embodiment. FIG. 18 shows a refractive index difference having a refractive index anisotropy obtained by synthesizing the first refractive index anisotropy of the first retardation plate and the second refractive index anisotropy of the second retardation plate according to the present embodiment. Schematic representation of relative positional relationship between isotropic medium, vapor deposition direction of this refractive index anisotropic medium, uniaxial refractive index anisotropy of third retardation plate, and liquid crystal molecules constituting liquid crystal panel It is one schematic diagram shown in. FIG. 19 shows a refractive index difference having a refractive index anisotropy obtained by synthesizing the first refractive index anisotropy of the first retardation plate and the second refractive index anisotropy of the second retardation plate according to the present embodiment. Schematic representation of relative positional relationship between isotropic medium, vapor deposition direction of this refractive index anisotropic medium, uniaxial refractive index anisotropy of third retardation plate, and liquid crystal molecules constituting liquid crystal panel It is the other schematic diagram shown in.

(Incident side retardation plate)
In FIG. 17A, a first retardation plate 15a1 is disposed on the side where light enters the liquid crystal panel 15c, and the first substrate 1501a on which the first deposition film 1503a of the first retardation plate 15a1 is deposited is illustrated. The side is arranged close to the liquid crystal panel 15c. At the same time, the optical axis of the first retardation plate 15a1 is along the same direction as 0:00 in the clear vision direction. In FIGS. 17A to 17G, the first polarizing plate 15b is disposed at the uppermost portion in the drawing, and the second polarizing plate 15d is disposed at the lowermost portion in the drawing.

  In addition, a second retardation plate 15e is disposed closer to the liquid crystal panel 15c than the first retardation plate 15a described above on the light incident side to the liquid crystal panel 15c. The second substrate 1501e on which the two vapor deposition films 1503e are deposited is disposed so as to be close to the liquid crystal panel 15c. At the same time, the optical axis of the second phase difference plate 15e is along the same direction as 9:00:00 in the clear vision direction.

  In addition, the third retardation plate 15f is disposed between the second retardation plate 15e and the liquid crystal panel 15c. In particular, as shown in FIG. 17G, the arrangement position of the third retardation plate 15f may be the arrangement position P1 between the first polarizing plate 15b and the first retardation plate 15a1, The arrangement position P2 may be between the first retardation plate 15a1 and the second retardation film 15e, or may be the arrangement position P3 between the liquid crystal panel 15c and the second polarizing plate 15d.

  Specifically, in the case of the arrangement shown in FIG. 17A, as shown in FIG. 18, (i) the long axis of the liquid crystal molecules 51 tilted along 10:30 in the clear vision direction. Direction, and (ii) a first retardation plate 15a having a first optical axis along the same direction as 0: 0 in the clear vision direction and a first phase plate in the same direction as 9: 0 in the clear vision direction. Since the main refractive index nx ′ ″ of the optical axis of the refractive index anisotropic medium 255ae formed by the second retardation plate 15e having two optical axes intersects, the first retardation plate 15a1 and the second retardation plate 15e and the third retardation plate 15f compensate three-dimensionally so that the optical anisotropy of the liquid crystal molecules 51 is directed toward optical isotropy.

  FIG. 17B shows a configuration in which the first retardation plate 15a1 and the second retardation plate 15e are replaced with each other in the configuration shown in FIG. 17A described above.

  In addition, the third retardation plate 15f is disposed between the second retardation plate 15e and the liquid crystal panel 15c.

  In FIG. 17C, on the side where light is incident on the liquid crystal panel 15c, a first retardation plate 15a having an optical axis along the same direction as 0: 0 in the clear vision direction is disposed. It arrange | positions so that the side of the 1st board | substrate 1501a1 in which the 1st vapor deposition film 1503a of the phase difference plate 15a1 was vapor-deposited may be close to the liquid crystal panel 15c. At the same time, on the side where the light is emitted from the liquid crystal panel 15c, a second retardation plate 15e whose optical axis is along the same direction as 9: 0 in the clear vision direction is disposed. The second substrate 1501e on which the second deposited film 1503e is deposited is disposed so as to be far from the liquid crystal panel 15c. At the same time, the optical axis of the second phase difference plate 15e is along the same direction as 9:00:00 in the clear vision direction.

In addition, a third retardation plate 15f is disposed between the first retardation plate 15a1 and the liquid crystal panel 15c. In particular, as shown in FIG. 17 (h), the arrangement position of the third retardation plate 15f may be the arrangement position P4 between the first polarizing plate 15b and the first retardation film 15a1, or the liquid crystal The arrangement position P5 between the panel 15c and the second retardation plate 15e may be set, or the arrangement position P6 between the liquid crystal panel 15c and the second polarizing plate 15d may be set. f) shows that the third retardation plate 15f is disposed between the above-described second retardation plate 15e and the liquid crystal panel 15c, and the first retardation plate 15a is disposed on the side where light enters the liquid crystal panel 15c. The second retardation plate 15e is disposed, and the first substrate 1501a and the second substrate 1501e corresponding to the second retardation plate 15e are disposed so as to be close to or distant from each other with respect to the liquid crystal panel 15c. . Specifically, in FIG. 17D, the first substrate 1501a on which the first vapor deposition film 1503a of the first retardation plate 15a is deposited is disposed so as to be far from the liquid crystal panel 15c. In addition, the second retardation plate 15e is disposed so that the second substrate 1501e side on which the second vapor deposition film 1503e is vapor-deposited is close to the liquid crystal panel 15c. In FIG. 17E, the first retardation plate 15a is disposed so that the side of the first substrate 1501a on which the first vapor deposition film 1503a is vapor-deposited is close to the liquid crystal panel 15c. At the same time, the second retardation plate 15e is disposed so that the second substrate 1501e side on which the second vapor deposition film 1503e is deposited is far from the liquid crystal panel 15c. In FIG. 17F, the first substrate 1501a on which the first vapor deposition film 1503a of the first retardation plate 15a is deposited is disposed so as to be far from the liquid crystal panel 15c. At the same time, the second retardation plate 15e is disposed so that the second substrate 1501e side on which the second vapor deposition film 1503e is deposited is far from the liquid crystal panel 15c.

(Output side retardation plate)
FIG. 17G shows a form in which the first retardation plate 15a and the second retardation plate 15e are arranged on the side from which light is emitted from the liquid crystal panel 15c. In particular, the first phase difference plate 15a and the second phase difference plate 15e arranged on the basis of the emission side can take various forms on the basis of the incident side described above.

  Specifically, in the case of the arrangement shown in FIG. 17 (g), as shown in FIG. 19, (i) the long axis of the liquid crystal molecules 51 inclined along 10:30 in the clear vision direction. Direction, and (ii) a first retardation plate 15a having a first optical axis along the same direction as 0: 0 in the clear vision direction and a first phase plate in the same direction as 9: 0 in the clear vision direction. Since the main refractive index nx ′ ″ of the optical axis of the refractive index anisotropic medium 255ae formed by the second retardation plate 15e having two optical axes intersects, the first retardation plate 15a1 and the second retardation plate 15e and the third retardation plate 15f compensate three-dimensionally so that the optical anisotropy of the liquid crystal molecules 51 is directed toward optical isotropy.

  In the projector according to the present invention, in addition to the nine types shown in FIG. 17, any of various types derived from these nine types may be adopted.

  On the other hand, if the configuration shown in FIG. 17G is employed, the first retardation plate 15a1, the second retardation plate 15e, and the third retardation plate 15f are arranged on the light emission side of the liquid crystal panel 15c. Compensation can be performed for the entire light transmitted through the panel 15c, and a better optical compensation effect can be obtained. If the form of FIG. 17G is adopted, the first retardation plate 15a1, the second retardation plate 15e, and the third retardation plate 15f are disposed on the light emission side of the liquid crystal panel 15c. The phase difference plate 15a1, the second phase difference plate 15e, and the third phase difference plate 15f can be moved away from the light source, and the first phase difference plate 15a1, the second phase difference plate 15e, and the second phase difference plate 15e are caused by light irradiation and the accompanying temperature rise. It is possible to effectively prevent the three phase difference plate 15f from being deteriorated, and the projector is excellent in reliability.

  17A, 17B, 17D to 17F, the first retardation plate 15a1 and the second retardation plate on the light incident side of the liquid crystal panel 15c. Since the 15e and the third retardation plate 15f are arranged, it is possible to make the light incident on the liquid crystal panel 15c after adjusting the appropriate phase difference with respect to the light from the light source.

  In particular, if the major axis direction of the liquid crystal molecules is another direction such as 1:30 in the clear vision direction, the optical axes of the first phase difference plate 15a1 and the second phase difference plate 15e are correspondingly changed. It goes without saying that the direction of extension also changes.

(Third embodiment)
Next, with reference to FIG.20 and FIG.21, the phase difference plate which concerns on 2nd Embodiment is demonstrated. FIG. 20 is a plan view of the retardation film according to the second embodiment (FIG. 20A) and an enlarged sectional view in which the HH ′ section in FIG. 20A is enlarged. FIG. 21 quantitatively shows the external perspective view of the retardation plate according to the second embodiment (FIG. 21A), the front phase difference according to the second embodiment, and the ratio of the two phase differences. It is a graph (FIG.21 (b)). The X direction, the Y direction, and the Z direction shown in FIGS. 20A, 20B, and 21A are common.

  As shown in FIGS. 20A and 20B, the above-described retardation plate 15a according to the second embodiment includes, for example, a first substrate 1501 made of a transparent glass substrate or the like, and a first substrate. And a vapor deposition film 1503 formed on 1501.

  The vapor deposition film 1503 is formed on the first substrate 1501 by depositing an inorganic material such as Ta 2 O 5 on the first substrate 1501 from an oblique direction D with respect to the first substrate 1501.

  Here, as shown in FIG. 20B, the vapor deposition film 1503 has a film structure including a portion where a column structure in which an inorganic material grows along the oblique direction D is formed when viewed microscopically. ing. An inorganic film having such a structure generates a phase difference more or less due to its fine structure. The vapor deposition film 1503 provided in the phase difference plate 15a has a columnar portion 1503at extending along the oblique direction D in which the inorganic substance is obliquely vapor-deposited on the first substrate 1501 in a cross-sectional view.

  In particular, as shown in FIG. 21A, the polar angle θ that defines the measurement direction for measuring the phase difference of light is an angle inclined with respect to the normal direction P of the substrate surface 15as. Typically, the polar angle is the angle of the line of sight when viewed from the front of the phase difference plate at 0 degree. In the present embodiment, the polar angle θ that is inclined from the normal direction P toward the oblique direction D is defined as negative, and the polar angle θ that is inclined in the opposite direction is defined as positive. Note that the azimuth direction of the measurement direction for measuring the phase difference of light, that is, the in-plane direction in the substrate surface 15as is, for the sake of simplicity of explanation, the oblique direction D in which the inorganic substance is obliquely deposited is the substrate surface 15as. Are aligned in the direction projected on the screen, in other words, in the Y direction. Typically, the vapor deposition angle and the polar angle θ described above may be on the same plane 15ah. Thereby, when the vapor deposition angle and the polar angle θ described above are set to be the same, the degree of improvement in contrast in the liquid crystal device can be grasped according to the phase difference of the inorganic substance itself.

  The ratio of the two phase differences according to the second embodiment means the ratio between the two phase differences with the polar angle as a variable. Typically, based on the phase difference when the polar angle is “30 degrees”, the phase difference when the polar angle is “30 degrees” and the polar angle is “−30 degrees”. The ratio R [30], which is the ratio to the phase difference at the time, is defined by the following equation (1).

R [30] = Ret (−30) / Ret (30) (1)
However, Ret (30) means a phase difference when the polar angle is “30 degrees”, and Ret (−30) means a phase difference when the polar angle is “−30 degrees”. Specifically, as shown in FIG. 21B, the phase difference when the polar angle is set to “30 degrees” is 9 (nm), and the phase difference when the polar angle is set to “−30 degrees”. When the phase difference is 54 (nm), by substituting “9” into Ret (30) in the formula (1) and substituting “54” into Ret (−30), the ratio R [30] = “6” can be obtained.

In particular, in the second embodiment, a ratio between two phase differences using two polar angles that are symmetric with respect to the normal direction as a variable will be described, but the present embodiment is not limited to this. The ratio of the two phase differences according to the second embodiment is a method such as the ratio of the phase difference when the polar angle is “30 degrees” and the phase difference when the polar angle is “−20 degrees”, for example. It may be a ratio between two phase differences using two polar angles that are not symmetrical with respect to the line direction as variables. Alternatively, the phase difference ratio according to the present embodiment is, for example, a phase difference when the polar angle is “0 degrees”, that is, a so-called front phase difference, and a phase difference when the polar angle is “−30 degrees”. It may be a ratio between two phase differences using two polar angles that are not symmetrical with respect to the normal direction as a variable. In short, as long as the ratio between two different phase differences with at least two different polar angles as variables, the correlation with contrast, theoretically, experimentally, empirically, It can be defined by simulation or the like.
(Quantitative analysis of contrast improvement due to the ratio of front phase difference, deposition angle and phase difference)
Next, with reference to FIG. 22 and FIG. 23, a quantitative analysis of contrast improvement caused by the ratio of the front phase difference, vapor deposition angle, and phase difference of the phase difference plate according to the second embodiment will be described. FIG. 22 is a graph showing a quantitative correlation between the front phase difference, the phase difference ratio, and the contrast of the phase difference plate according to the second embodiment. The double circles, black diamonds, white circles, white squares, and white inverted triangles shown in FIG. 22 are contrasts of “1700-1800”, “1600-1700”, It corresponds to “1500 to 1600”, “1400 to 1500”, and “1300 to 1400”, respectively. FIG. 23 is a graph showing a quantitative correlation between the phase difference, polar angle, and deposition angle when the thicknesses of the retardation plates according to the second embodiment are the same (FIG. 23A), FIG. 23B is a schematic diagram showing the magnitude relationship between the vapor deposition angles according to the embodiment, and the phase difference, polar angle, and phase difference when the vapor deposition angles in the phase difference plate according to the second embodiment are the same. It is the graph (FIG.23 (c)) which showed the quantitative correlation of the thickness of the board. In FIGS. 23A and 23C, the horizontal axis indicates the polar angle, and the vertical axis indicates the phase difference.

  According to the study by the present inventor, in order to realize a relatively high contrast in the range of “1700 to 1800” as shown by the double circle and the area A1 in FIG. The phase difference ratio R [30] is set to a range YA1 between about “1.5” and about “3.2”, and the front phase difference is set to a range XA1 between about “20” and about “30”. It is preferable. Alternatively, as shown by the double circle and the region A2 in FIG. 22, in order to realize a relatively high contrast in the range of “1700 to 1800”, the phase difference ratio R [30] Is in the range YA2 between about “6.5” and about “9.5”, and the front phase difference is preferably in the range XA2 between about “15” and about “17”.

  Specifically, according to the research by the present inventors, as shown in FIGS. 23A and 23B, for example, when the thickness of the retardation plate 15a is the same, the deposition angle becomes large. In other words, the amount of change in the phase difference per fixed angle of the polar angle becomes smaller as the oblique direction during vapor deposition approaches the normal direction and the polar angle during vapor deposition approaches zero. ing. Accordingly, it has been found that the phase difference ratio R [30] approaches the value of “1” as the deposition angle increases. Alternatively, according to the research by the inventors of the present application, as shown in FIGS. 23A and 23B, for example, when the thickness of the retardation plate 15a is the same, as the deposition angle decreases, In other words, it was found that the amount of change in the phase difference per fixed angle of the polar angle increases as the oblique direction during deposition moves away from the normal direction and the polar angle during deposition becomes greater than zero. ing. As a result, it has been found that the phase difference ratio R [30] greatly deviates from the value of “1” as the deposition angle decreases.

  In addition, according to a study by the inventors of the present application, as shown in FIG. 23C, for example, when the vapor deposition angle is the same, the polar angle is set to “0” as the thickness of the retardation film 15a increases. It has been found that the phase difference at the time of “degree”, the so-called front phase difference, increases. Alternatively, according to the research by the present inventor, as shown in FIG. 23C, for example, when the deposition angle is the same, the front phase difference decreases as the thickness of the phase difference plate 15a decreases. It has been found. Specifically, a thick line corresponds to a case where the thickness of the retardation plate is relatively large, and a dotted line corresponds to a case where the thickness of the retardation plate is relatively small.

  As described above, by appropriately changing the deposition angle and the film thickness of the retardation plate, it is possible to set the phase difference ratio and the front phase difference so that the contrast is maximized.

  The front phase difference ranges XA1 and XA2 constitute one and other specific examples of the first predetermined range according to the present invention. Further, the phase difference ratios YA1 and YA2 constitute one and other specific examples of the second predetermined range according to the present invention.

(Correlation between front phase difference and phase plate rotation angle range and contrast)
Next, with reference to FIG. 24, the correlation between the front phase difference and the rotation angle range of the phase difference plate (hereinafter referred to as “adjustment angle range” as appropriate) and the contrast according to the present embodiment will be described. FIG. 24 is a graph (FIG. 24A) showing a quantitative correlation between the front phase difference and the adjustment angle according to the present embodiment, and the front phase difference and the phase difference plate according to the present embodiment. It is the graph (FIG.24 (b)) which showed the quantitative correlation of this adjustment angle and contrast.

  As shown in FIG. 24A, as the front phase difference increases, the adjustment angle of the phase difference plate 15a until the maximum contrast is obtained can be reduced. In other words, as the front phase difference decreases, the adjustment angle of the phase difference plate 15a until the maximum contrast is obtained can be increased. Specifically, as shown in FIG. 24A, when the front phase difference Ret (0) is “30 (nm)”, the adjustment angle of the phase difference plate 15a can be set to 3 degrees, for example. At the same time, when the front phase difference Ret (0) is “15 (nm)”, the adjustment angle of the phase difference plate 15a can be set to, for example, 15 degrees.

  In addition, as shown in FIG. 24B, the amount of change in contrast per unit angle of the adjustment angle of the phase difference plate 15a can be increased as the front phase difference increases. In other words, the amount of change in contrast per unit angle of the adjustment angle of the phase difference plate 15a can be reduced as the front phase difference decreases. Specifically, as shown in FIG. 24B, when the front phase difference Ret (0) is “30 (nm)”, the maximum is obtained when the adjustment angle of the phase difference plate 15a is set to 3 degrees. Contrast can be obtained. When the front phase difference Ret (0) is “15 (nm)”, the maximum contrast can be obtained when the adjustment angle of the phase difference plate 15a is 5 degrees. In addition, when the front phase difference Ret (0) is “30 (nm)”, the amount of change in the contrast per unit angle of the adjustment angle of the phase difference plate 15a is such that the front phase difference Ret (0) is “15 ( nm) ”can be made larger than the amount of change in contrast per unit angle of the adjustment angle of the retardation plate 15a, and a steep curve is shown in FIG.

  According to the second embodiment, in addition to the setting of the ratio value of the two phase differences described above, the front phase difference value is set to an appropriate value, so that in the assembly process of manufacturing the projector, or the user In this adjustment operation, the desired adjustment angle range of the phase difference plate 15a can be determined easily and appropriately, which is very advantageous in practice.

(Fourth embodiment)
Next, with reference to FIGS. 25 and 26, a polarizing plate and a retardation film according to the fourth embodiment will be described. FIG. 25 is an explanatory diagram showing the configuration of the liquid crystal light valve according to the fourth embodiment. Note that in the fourth embodiment, components that are substantially the same as in the above-described embodiment are denoted by the same reference numerals, and a description thereof will be omitted as appropriate.

  As shown in FIG. 25, the phase difference plate 15a according to the fourth embodiment (that is, another specific example of the first phase difference plate according to the present invention) is arranged in the order of being arranged far from the liquid crystal panel 15c. The first deposited film 1501c on which the refractive index anisotropic medium 255c that holds the refractive index anisotropy is vertically deposited, the first substrate 1501, and the refractive index anisotropic medium 255a that holds the refractive index anisotropy are oblique. A second vapor-deposited film 1503 and a second substrate 1502 that have been vapor-deposited are provided.

  In general, the first vapor deposition film 1501c such as a C plate generates minute bubbles in the manufacturing process, and is contained in the first vapor deposition film 1501c to a greater or lesser extent. On the other hand, in the present embodiment, the first vapor deposition film 1501c is disposed at a distance farthest from the liquid crystal panel 15c as compared with the first substrate 1501, the second vapor deposition film 1503, and the second substrate 1502. Thereby, the degree of focusing on the bubbles contained in the first vapor deposition film 1501c can be significantly reduced. Thereby, it can suppress effectively that the bubble contained in the 1st vapor deposition film 1501c is projected, and has a bad influence on a projection image | video.

(Detailed configuration of retardation plate)
Here, with reference to FIG. 26, the detailed structure of the phase difference plate which concerns on this embodiment is demonstrated. FIG. 26 shows a vapor deposition direction that defines the relative positional relationship between the two types of refractive index anisotropic media constituting the retardation plate according to the fourth embodiment and the first substrate of the retardation plate. It is the external appearance perspective view which showed the vapor deposition angle typically.

  As shown in FIG. 26, in the first vapor deposition film 1501c constituting the retardation film 15a, the refractive index anisotropic medium 255c is vertically vapor deposited on the first substrate 1501 from the lower side to the upper side in FIG. Has been. Specifically, as described above, the main refractive indexes nx ′, ny ′, and nz ′ of the first vapor deposition film 1501c satisfy the relationship of nx ′ = ny ′> nz ′.

  In addition, in the second vapor deposition film 1503 constituting the phase difference plate 15a, the refractive index anisotropic medium 255a has a predetermined direction, that is, the vapor deposition direction from the upper side to the lower side in FIG. The oblique deposition is performed on one substrate 1501. In addition, the refractive index anisotropic medium 255a has an optical axis corresponding to the main refractive index nx of the refractive index anisotropic medium 255a having a predetermined angle with the plane direction of the first substrate 1501, that is, a deposition angle. Is obliquely deposited. This deposition angle can be rephrased as a value obtained by subtracting the angle between the normal line of the first substrate 1501 and the optical axis corresponding to the main refractive index nx of the refractive index anisotropic medium 255a from 90 degrees. Alternatively, this deposition angle can be rephrased as the angle between the optical axis corresponding to the main refractive index nx of the refractive index anisotropic medium 255a and the deposition direction.

  For example, when the first vapor deposition film 1501c such as a C plate is formed on the second vapor deposition film 1503 by oblique deposition, or the second vapor deposition film 1503 is formed as a first vapor deposition film 1501c such as a C plate. When formed by the oblique vapor deposition method, moisture is mixed into the first vapor deposition film 1501c during the formation process, and the technical problem that the quality of the first vapor deposition film 1501c is deteriorated. Arise.

  On the other hand, according to the fourth embodiment, for example, the first vapor deposition film 1501c such as a C plate is formed on one surface of the first substrate 1501, and the second vapor deposition film 1503 is formed on the other side of the first substrate 1501. Form on the surface. Accordingly, when the first vapor deposition film 1501c such as a C plate is formed by the sputtering method, the degree of moisture mixed into the first vapor deposition film 1501c can be reduced. Therefore, the quality of the first vapor deposition film 1501c can be reduced. Can be further improved.

  In addition, as another specific example of the first retardation plate 15a (or 15a1) and the second retardation plate 15e according to the present embodiment, the alignment is performed in an inclined state with respect to the plate surface of the retardation plate (tilt alignment). A material provided with an optically anisotropic layer made of a discotic liquid crystal can be exemplified. These retardation plates can be prepared by providing an alignment film on a support such as triacetylcellulose (TAC) and coating a discotic liquid crystal such as a triphenylene derivative on the alignment film. More specifically, after preparing a pair of supports formed with an alignment film such as polyimide on the surface, a discotic liquid crystal is coated on one support and then the discotic liquid crystal is formed on the other support. Is inserted. And after forming a discotic nematic (ND) phase by heat processing, it superposes | polymerizes with an ultraviolet-ray etc. and fixes an orientation state. During the formation of the ND phase, the discotic liquid crystal is given a pretilt by the alignment film, and is formed in a state where the optical axis is inclined obliquely. The tilt angle of the optical axis can be controlled by alignment processing (rubbing or the like) of the alignment film.

  Alternatively, as another specific example of the first retardation plate 15a (or 15a1) and the second retardation plate 15e according to the present embodiment, it is also produced by stretching polycarbonate or norbornene resin or the like under shear stress. be able to. In this case, the material resin is stretched from two directions while being heated to near the glass transition point, and is sandwiched between a pair of heated substrates. Then, while applying pressure to the material resin from the outside of one substrate, the pair of substrates are shifted in opposite directions. Thereby, shear stress is applied to the upper and lower surfaces of the material resin in opposite directions, and the optical axis direction of the optical body constituting the material resin is inclined obliquely. The tilt angle of the optical axis can be controlled by the magnitude of the shear stress.

  The present invention is not limited to the above-described embodiments, 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. The optical compensation method of the liquid crystal device is also included in the technical scope of the present invention.

1 is a schematic configuration diagram of a liquid crystal projector according to an embodiment of the present invention. FIG. 2 is an overall configuration diagram (FIG. 2A) of a liquid crystal panel according to the present embodiment and a sectional configuration diagram (FIG. 2B) along line H-H ′ in FIG. 2A. It is explanatory drawing which shows the structure of the liquid crystal light valve which concerns on this embodiment. It is a figure which shows the optical axis arrangement | positioning of each structural member in FIG. 3 which concerns on this embodiment. The vapor deposition direction etc. which prescribe | regulate the relative positional relationship of the refractive index anisotropic medium which comprises the 1st phase difference plate which concerns on this embodiment, and the board | substrate corresponding to a 1st phase difference plate were shown typically. Appearance perspective view (FIG. 5A), vapor deposition direction that defines the relative positional relationship between the refractive index anisotropic medium constituting the second retardation plate and the substrate corresponding to the second retardation plate, etc. FIG. 5B is a schematic perspective view of the outer appearance of FIG. 5 and a refractive index anisotropic medium constituting the first phase difference plate and a refractive index anisotropic medium constituting the second phase difference plate. It is the external appearance perspective view (FIG.5 (c)) which showed the relative positional relationship of a refractive index anisotropic medium and a board | substrate schematically. The relative positional relationship of the optical axis of the refractive index anisotropic medium which comprises the 1st and 2nd phase difference plate which concerns on this embodiment, and the optical axis of the liquid crystal molecule which comprises a liquid crystal panel was shown typically. FIG. 6 is a plan view (FIG. 6A) and an elevation view (FIG. 6B). Optical Anisotropy of Refractive Index Anisotropy Medium Combining Refractive Index Anisotropy Medium Constructing First Retardation Plate According to Embodiment and Refractive Index Anisotropy Medium Containing Second Retardation Plate FIG. 2 is a schematic diagram conceptually showing how optical isotropy is realized by combining the optical anisotropy of liquid crystal molecules constituting the liquid crystal panel. A bar graph (FIG. 8A) showing the relationship between the film thickness of the first and second retardation plates according to the present embodiment and the combination of the first and second retardation plates, It is the graph (Drawing 8 (b)) which showed quantitatively the correlation of the film thickness of the 1st and 2nd phase contrast plate concerning an embodiment, and the contrast of light. It is the graph which showed quantitatively the correlation with the vapor deposition angle and contrast with respect to the 1st board | substrate of the refractive index anisotropic medium which comprises the 1st and 2nd phase difference plate which concerns on this embodiment. The first and second phase differences and polar angles when the film thicknesses of the first and second phase difference plates according to the present embodiment and the vapor deposition angle of the refractive index anisotropic medium constituting the phase difference plate are used as variables. 11 is a graph (FIG. 10A and FIG. 10B) that quantitatively shows the correlation. It is a schematic block diagram of the liquid-crystal projector which concerns on the 2nd Embodiment of this invention. It is the graph which showed the correlation of the kind of phase difference plate, phase difference, and polar angle in the phase difference plate which concerns on the 2nd Embodiment of this invention. It is the graph which showed the correlation of the kind of phase difference plate in the phase difference plate which concerns on the 2nd Embodiment of this invention, and contrast. It is a figure which shows the optical axis arrangement | positioning of each structural member in FIG. 6 is a bar graph quantitatively showing the correlation between the contrast realized by the first to third phase difference plates according to the present embodiment and the contrast realized by the phase difference plate according to the comparative example. FIG. 16 is a distribution diagram (FIG. 16A and FIG. 16B) showing the variation in luminance in the liquid crystal panel to which the phase difference plate according to this embodiment and the comparative example is applied. It is the schematic (FIG. 17 (a) to FIG. 17 (i)) which shows the arrangement | positioning form of the structural member in the liquid crystal light valve 15 which concerns on this embodiment. A refractive index anisotropic medium having a refractive index anisotropy obtained by combining the first refractive index anisotropy of the first retardation plate and the second refractive index anisotropy of the second retardation plate according to the present embodiment; 1 schematically shows the relative positional relationship between the deposition direction of the refractive index anisotropic medium, the uniaxial refractive index anisotropy of the third retardation plate, and the liquid crystal molecules constituting the liquid crystal panel. FIG. A refractive index anisotropic medium having a refractive index anisotropy obtained by combining the first refractive index anisotropy of the first retardation plate and the second refractive index anisotropy of the second retardation plate according to the present embodiment; In addition to the schematic illustration of the relative positional relationship between the deposition direction of the refractive index anisotropic medium, the uniaxial refractive index anisotropy of the third retardation plate, and the liquid crystal molecules constituting the liquid crystal panel FIG. FIG. 21 is a plan view of a retardation plate according to a second embodiment (FIG. 20A) and an enlarged cross-sectional view in which the H-H ′ cross section in FIG. 20A is enlarged. FIG. 21A is an external perspective view of the retardation plate according to the second embodiment (FIG. 21A), and a graph quantitatively showing the front phase difference according to the second embodiment and the ratio of the two phase differences. (B)). It is the graph which showed the quantitative correlation between the front phase difference of the phase difference plate which concerns on 2nd Embodiment, the ratio of phase difference, and contrast. A graph (FIG. 19A) showing a quantitative correlation between the phase difference, polar angle, and vapor deposition angle when the thicknesses of the retardation plates according to the second embodiment are the same, according to the second embodiment. Schematic diagram showing the relationship between the deposition angles (FIG. 19B), and the retardation, polar angle, and retardation plate thickness when the deposition angles in the retardation plate according to the second embodiment are the same. It is the graph (FIG.19 (c)) which showed quantitative correlation of these. A graph (FIG. 24A) showing a quantitative correlation between the front phase difference and the adjustment angle according to the present embodiment, and the front phase difference and the adjustment angle of the phase difference plate and the contrast according to the present embodiment. It is the graph (FIG.24 (b)) which showed the quantitative correlation. It is explanatory drawing which shows the structure of the liquid crystal light valve which concerns on 4th Embodiment. The vapor deposition direction and vapor deposition angle which prescribe | regulate the relative positional relationship of two types of refractive-index anisotropic media which comprise the phase difference plate which concerns on 4th Embodiment, and the 1st board | substrate of a phase difference plate are shown typically. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Projector, 11 ... Screen, 12 ... Light source, 15, 16, 17, 215 ... Liquid crystal device, 15a, 15a1, 16a, 17a ... 1st phase difference plate, 15as ... Substrate surface, 15ah ... Plane, 15b, 16b, 17b, 15d, 16d, 17d ... polarizing plate, 15c, 16c, 17c ... liquid crystal panel, 15e, 16e, 17e ... second retardation plate, 15f ... third retardation plate, 31 ... counter substrate, 32 ... TFT array substrate 43a, 98a ... orientation direction, 43, 98 ... alignment film, 51 ... liquid crystal molecule, 81a ... rotation axis, 81e ... rotation axis, 255a ... refractive index anisotropic medium, 255e ... refractive index anisotropic medium, 255c ... Refractive index anisotropic medium, 1501a ... first substrate, 1501e ... second substrate, 1503a ... first vapor deposition film, 1503e ... second vapor deposition film, 1503at ... columnar portion, D ... diagonal direction A1, A2 ... area, LB ... blue light, LG ... green light, LR ... red light, P ... pretilt direction.

Claims (18)

A liquid crystal panel that modulates light by sandwiching a vertical alignment type liquid crystal containing liquid crystal molecules pre-tilted by the alignment film between a pair of substrates each having an alignment film;
A pair of polarizing plates disposed across the liquid crystal panel;
Wherein it is disposed a pair of polarizing plates, (ia) the first substrate, the (ii-a) uniaxial optical axis of the uniaxial refractive index anisotropic medium to have a refractive index anisotropy uniaxial thickness vertically evaporated film and is vertically deposited on the first substrate along the direction (iii-a) a first optical axis of the first refractive index anisotropic medium having a first refractive index anisotropy a first retardation plate having a first deposited film is oblique evaporation on the vertically evaporated film so as to be inclined in a first direction to cancel the change in characteristics of the light by the pretilt,
The second optical axis of the second refractive index anisotropic medium is disposed between the pair of polarizing plates, and has (ib) a second substrate and (ii-b) a second refractive index anisotropy . a second retardation plate having a second deposition films oblique evaporation on the second substrate so as to be inclined in a different second direction wherein the first direction together with the cancel changes in the characteristics,
Including
The first retardation plate is rotatable about the normal line of the liquid crystal panel substrate, and the second retardation plate is rotated about the normal line independently of the first retardation plate. A liquid crystal device which is possible .   The thickness of the vertical vapor deposition film and the refractive index in the thickness direction of the vertical vapor deposition film are 0 degrees when viewed from the front of one polarizing plate located on the light emission side of the pair of polarizing plates. 2. The liquid crystal device according to claim 1, wherein a phase difference is set to be 20 nm or less when a polar angle indicating a line-of-sight angle is 30 °.   3. The liquid crystal device according to claim 1, wherein the first direction and the second direction are in a positional relationship sandwiching a major axis direction of the liquid crystal molecules to which the pretilt is applied.   4. The liquid crystal device according to claim 1, wherein a relation angle that is an angle formed by the first direction and the second direction is 70 degrees to 110 degrees. 5. 5. The liquid crystal according to claim 1, wherein at least one of the first refractive index anisotropic medium and the second refractive index anisotropic medium is biaxial. 6. apparatus. In the first refractive index anisotropic medium , when the first optical axis is the X axis, the refractive index in the X axis direction is larger than the refractive index in the Y axis direction, and the refractive index in the Y axis direction is Z. In addition to or instead of having a magnitude relationship of greater than the refractive index in the axial direction, the second refractive index anisotropic medium has a refractive index in the X-axis direction when the second optical axis is the X-axis. The refractive index in the Y-axis direction is larger than the refractive index in the Y-axis direction, and the refractive index in the Y-axis direction is larger than the refractive index in the Z-axis direction. LCD device.   The first front phase difference that is a phase difference in the front direction of the first phase difference plate is different from a second front phase difference that is a phase difference in the front direction of the second phase difference plate. The liquid crystal device according to any one of 1 to 6. The pair of transmission axes of the pair of polarizing plates are orthogonal to each other and 45 degrees from the major axis direction of the liquid crystal molecules provided with the pretilt when viewed from the normal direction of the first substrate or the second substrate. There are no angles,
In the first retardation plate, the first optical axis is along one direction of the pair of transmission axes,
8. The liquid crystal device according to claim 1, wherein in the second retardation plate, the second optical axis is along the other direction of the pair of transmission axes.   The liquid crystal device according to claim 1, wherein at least one of the first vapor deposition film and the second vapor deposition film includes an inorganic material. 10. The liquid crystal device according to claim 1, wherein the pretilt is in a range of 2 to 8 degrees from one normal line of the pair of substrates .   In addition to or instead of the film thickness of at least one of the first vapor-deposited film and the vapor-deposited film, the vapor deposition angle, which is an angle formed by oblique vapor deposition of the one vapor-deposited film, is (i) the retardation plate In addition to being set so that the front phase difference, which is the phase difference in the front direction when viewed from the light exit side in the above, is within the first predetermined range, (ii) different from the normal direction of the phase difference plate In addition, the first phase difference generated when the light is incident from the first direction along the vapor deposition direction, which is the direction in which the one vapor deposition film is obliquely vapor-deposited, and the first direction relative to the normal direction. 2. The ratio of a second phase difference generated when the light is incident from a second direction that is symmetrical to the first direction is set to be within a second predetermined range. The liquid crystal device according to any one of 1 to 10.   The film thickness and the deposition angle are: (i) Contrast change with respect to a unit change amount of the rotation angle when the retardation plate is rotated with the normal direction as a rotation axis as the front phase difference increases. In addition to or instead of being set to increase the amount, (ii) as the front phase difference decreases, the amount of change in contrast with respect to the unit change amount is set to decrease. The liquid crystal device according to claim 11. A liquid crystal panel that modulates light by sandwiching a vertical alignment type liquid crystal containing liquid crystal molecules pre-tilted by the alignment film between a pair of substrates each having an alignment film;
A pair of polarizing plates disposed across the liquid crystal panel;
It is disposed on the pair of polarizing plates, (ia) the first substrate, and (ii-a) a first optical axis of the first refractive index anisotropic medium to have a first refractive index anisotropy the pretilt a first retardation plate having a first deposited film is oblique evaporation on the first substrate so as to be inclined in a first direction to cancel the change in characteristics of the light by,
Wherein it is disposed a pair of polarizing plates, by (ib) a second substrate and (ii-b) a second optical axis of the second refractive index anisotropic medium to have a second refractive index anisotropy the pretilt a second retardation plate having a second deposition films oblique evaporation on the second substrate so as to be inclined in a different second direction wherein the first direction together with the cancel the change in characteristics of the light,
Wherein is disposed a pair of polarizing plates, a third phase difference plate uniaxial optical axis of the uniaxial refractive index anisotropic medium to have a refractive index anisotropy of uniaxial property in the thickness direction,
Including
The first retardation plate is rotatable about the normal line of the liquid crystal panel substrate, and the second retardation plate is rotated about the normal line independently of the first retardation plate. A liquid crystal device characterized in that it is possible . A liquid crystal device according to any one of claims 1 to 12,
A light source that emits the light;
A projector comprising: a projection optical system that projects the modulated light. A liquid crystal device according to claim 13,
A light source that emits the light;
A projector comprising: a projection optical system that projects the modulated light. An optical compensation method for performing optical compensation in the liquid crystal device according to any one of claims 1 to 13,
A first optical adjustment step of rotating at least one of the first retardation plate and the second retardation plate around the normal line of the liquid crystal panel as a rotation axis;
A second optical adjustment step of rotating the other retardation plate of the first retardation plate and the second retardation plate about the normal line of the substrate of the liquid crystal panel;
An optical compensation method for a liquid crystal device. A liquid crystal panel that modulates light by sandwiching a vertical alignment type liquid crystal containing liquid crystal molecules pre-tilted by the alignment film between a pair of substrates each having an alignment film;
A pair of polarizing plates disposed across the liquid crystal panel;
Wherein it is disposed a pair of polarizing plates, (ia) the first substrate, the (ii-a) uniaxial optical axis of the uniaxial refractive index anisotropic medium to have a refractive index anisotropy uniaxial thickness A vertical vapor deposition film vertically vapor deposited on one side of the first substrate along the vertical direction, and (iii-a) a first optical axis of the first refractive index anisotropic medium having a first refractive index anisotropy medium . A first retardation plate having a first vapor deposition film obliquely vapor-deposited on the other side of the first substrate so as to incline in a first direction that cancels the characteristic change of the light due to the pretilt,
Wherein it is disposed a pair of polarizing plates, (ib) a second substrate and (ii-b) a second optical axis is the characteristic change of the second refractive index anisotropic medium to have a second refractive index anisotropy a second retardation plate having a second deposition films oblique evaporation on the second substrate so as to be inclined in a different second direction wherein the first direction together with counteract,
Including
The first retardation plate is rotatable about the normal line of the liquid crystal panel substrate, and the second retardation plate is rotated about the normal line independently of the first retardation plate. A liquid crystal device which is possible .   The liquid crystal device according to claim 17, wherein the vertical vapor deposition film is disposed farther from the liquid crystal panel than the first vapor deposition film.