Liquid crystal device, display device, and light modulation module

Abstract

A liquid crystal device, a display device, and a light modulation module capable of reducing a decrease in display quality caused by a reverse deflection region. The liquid crystal device includes a liquid crystal panel having a liquid crystal layer (5) as a first liquid crystal layer; a first polarizing plate provided on a light incident side of the liquid crystal panel; a second polarizing plate provided on a light emission side of the liquid crystal panel; a first phase difference control element (60) as a first phase difference adjustment element, which is disposed between the first polarizing plate and the liquid crystal panel, has a liquid crystal layer (67) as a second liquid crystal layer; a second phase difference control element (70) as a second phase difference adjustment element, which is disposed between the liquid crystal panel and the second polarizing plate, has a liquid crystal layer (77) as a third liquid crystal layer; and a first phase difference control element drive section (68) and a second phase difference control element drive section (78) as control sections, which control a phase difference of the liquid crystal layer (67) and a phase difference of the liquid crystal layer (77).

Description

Technical Field

[0001] This invention relates to liquid crystal devices, display devices, and optical modulation modules. Background Technology

[0002] In the display of a liquid crystal panel, for example, at the boundary between text and background, where white pixels and black pixels are adjacent, a high potential is applied to the pixel electrode of the white pixel, while a low potential is applied to the pixel electrode of the black pixel. Therefore, due to the lateral electric field between the pixel electrodes of the white pixel and the pixel electrodes of the black pixel, a reverse tilt domain is sometimes generated in which the liquid crystal molecules are oriented in a direction different from the desired orientation direction.

[0003] It is known that the formation of reverse deflection regions in liquid crystal panels can cause a decrease in display quality. This is especially true in small, high-resolution liquid crystal panels, where the influence of the lateral electric field becomes even greater; therefore, suppressing reverse deflection regions has become a key challenge.

[0004] In Patent Document 1, as a technique to suppress the generation of such reverse deflection regions, a technique is disclosed that weakens the lateral electric field by correcting grayscale data in a way that reduces the difference in applied voltage between pixels.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2012-252206

[0006] However, if grayscale data is corrected in order to reduce the transverse electric field, the change in the displayed content that accompanies the correction, such as the blurring of the image, can be easily visually confirmed by the viewer, and sometimes other problems such as display reversal can occur.

[0007] The present invention was made in view of the above circumstances, and one of its objectives is to suppress the reduction in display quality caused by the reverse deflection region. Summary of the Invention

[0008] One aspect of the liquid crystal device of this application includes: a liquid crystal panel having a first liquid crystal layer; a first polarizing element disposed on the light incident side of the liquid crystal panel; a second polarizing element disposed on the light emitting side of the liquid crystal panel; a first phase difference adjustment element disposed between the first polarizing element and the liquid crystal panel, having a second liquid crystal layer; a second phase difference adjustment element disposed between the liquid crystal panel and the second polarizing element, having a third liquid crystal layer; and a control unit that controls the voltage applied to the second liquid crystal layer and the third liquid crystal layer.

[0009] One aspect of the display device of this application includes: a first liquid crystal panel that modulates light of a first wavelength; and a second liquid crystal panel that modulates light of a second wavelength different from the first wavelength. The display device further includes: a first phase difference adjustment element disposed on the light incident side of the first liquid crystal panel and having a second liquid crystal layer; a second phase difference adjustment element disposed on the light emitting side of the first liquid crystal panel and having a third liquid crystal layer; and a control unit that controls the voltage applied to the second liquid crystal layer and the third liquid crystal layer.

[0010] One aspect of the light modulation module of this application includes: a liquid crystal panel having a first liquid crystal layer; a first polarizing element disposed on the light incident side of the liquid crystal panel; a second polarizing element disposed on the light emitting side of the liquid crystal panel; a first phase difference adjustment element disposed between the first polarizing element and the liquid crystal panel, having a second liquid crystal layer; and a second phase difference adjustment element disposed between the liquid crystal panel and the second polarizing element, having a third liquid crystal layer. Attached Figure Description

[0011] Figure 1 This is a schematic structural diagram of a projection-type display device using the liquid crystal device of Embodiment 1.

[0012] Figure 2 This is a top view showing one way of representing a liquid crystal panel combined with a liquid crystal device.

[0013] Figure 3 This is an explanatory diagram schematically showing a cross-section of a liquid crystal device.

[0014] Figure 4 This is an explanatory diagram schematically illustrating the structure of the liquid crystal layer in an LCD panel.

[0015] Figure 5A This is an explanatory diagram for Mode 1.

[0016] Figure 5B This is an explanatory diagram for Mode 1.

[0017] Figure 6A This is an explanatory diagram for mode 2.

[0018] Figure 6B This is an explanatory diagram for mode 2.

[0019] Figure 7 This is a graph showing the relationship between the phase difference of the phase difference control element and the display quality of the image.

[0020] Figure 8 This is a functional block diagram representing the structure related to phase difference control.

[0021] Figure 9This is a flowchart for calculating the phase difference of the phase difference control element based on brightness.

[0022] Figure 10A This is an explanatory diagram illustrating a bright display screen example.

[0023] Figure 10B It is a brightness histogram of a bright display screen.

[0024] Figure 11A This is an illustration of an example of a dark display screen.

[0025] Figure 11B It is the brightness histogram of the dark display screen.

[0026] Figure 12 This is a flowchart for calculating the phase difference of the phase difference control element based on the contrast ratio.

[0027] Figure 13A This is an explanatory diagram illustrating an example of a low-contrast display.

[0028] Figure 13B It is the brightness histogram of a low-contrast display.

[0029] Figure 14A This is an explanatory diagram showing an example of a high-contrast display screen.

[0030] Figure 14B It is the brightness histogram of a high-contrast display.

[0031] Label Explanation

[0032] 1, 1B, 1G, 1R: Liquid crystal device; 4: Optical modulation module; 5: Liquid crystal layer; 5a: Liquid crystal molecule; 9a: Pixel electrode; 10: First substrate; 10a: Display area; 16: First alignment film; 16a: Pillar; 19: Substrate body; 20: Second substrate; 21: Common electrode; 26: Second alignment film; 26a: Pillar; 29: Substrate body; 51: First polarizer; 52: Second polarizer; 60 60B, 60G, 60R: First phase difference control element; 61: Third substrate; 62: Fourth substrate; 63, 64: Electrodes; 65: Third alignment film; 66: Fourth alignment film; 67: Liquid crystal layer; 67a: Liquid crystal molecule; 68: First phase difference control element driving section; 70, 70B, 70G, 70R: Second phase difference control element; 71: Fifth substrate; 72: Sixth substrate; 73, 74: Electrodes; 7 5: Fifth alignment film; 76: Sixth alignment film; 77: Liquid crystal layer; 77a: Liquid crystal molecule; 78: Second phase difference control element driving unit; 80: Image processing unit; 81: Frame memory; 82: Image signal output unit; 83: Histogram generation unit; 84: Calculation unit; 90: Phase difference adjustment unit; 91: Phase difference determination unit; 92: Phase difference control signal output unit; 95: Brightness detection unit; 100, 100B, 10 0G, 100R: LCD panel; 110: Panel driving unit; 200: Laser light source; 300: Projection optical system; 500: Screen; 510: Projection surface; 1000: Projection type display device; L: Light; L1, L1a, L1b, L1c: First linearly polarized light; L2b, L2c, L2d: Second linearly polarized light; L3a: Circularly polarized light; L3b: Right-handed circularly polarized light; L4b: Left-handed circularly polarized light. Detailed Implementation

[0033] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0034] In the following figures, the dimensions of each component are made different from their actual size in order to make each component appear identifiable.

[0035] Furthermore, in the following figures, for ease of explanation, mutually orthogonal X-axis, Y-axis, and Z-axis will be used appropriately. One direction along the X-axis will be labeled X1, and the direction opposite to X1 will be labeled X2. One direction along the Y-axis will be labeled Y1, and the direction opposite to Y1 will be labeled Y2. One direction along the Z-axis will be labeled Z1, and the direction opposite to Z1 will be labeled Z2. In this embodiment, X1 corresponds to the first direction, and Y1 corresponds to the second direction.

[0036] In addition, the view along the Z2 or Z1 direction will be referred to as "top view" or "top view". Furthermore, the view taken from a direction perpendicular to the section containing the Z-axis will be referred to as "section view" or "section view".

[0037] Furthermore, in the following description, for example, regarding a substrate, the term "on the substrate" indicates any of the following: a case where the substrate is disposed in contact with the substrate, a case where the substrate is disposed on the substrate with respect to other structures, or a case where a portion of the substrate is disposed in contact with the substrate and a portion is disposed on the substrate with respect to other structures.

[0038] 1. Implementation Method 1

[0039] 1.1. Overview of Projection Display Devices Using Liquid Crystal Devices

[0040] Figure 1 This is an explanatory diagram showing the schematic structure of a projection-type display device using the liquid crystal device of this embodiment.

[0041] In this embodiment, the projection display device 1000 is an example of a display device. Furthermore, the projection display device 1000 is configured to include a liquid crystal device 1.

[0042] Furthermore, in this embodiment, the structure comprising the liquid crystal panel 100 (described later), the first polarizing plate 51 as the first polarizing element, the second polarizing plate 52 as the second polarizing element, the first phase difference control element 60, and the second phase difference control element 70 in the liquid crystal device 1 is sometimes referred to as the light modulation module 4. The light modulation module 4 does not need to include all the structures included in the liquid crystal device 1; it only needs to include at least the first phase difference control element 60 (described later) as the first phase difference adjustment element and the second phase difference control element 70 (described later) as the second phase difference adjustment element. Functionally, it only needs to have the ability to convert linearly polarized light into desired polarized light between linearly polarized and circularly polarized light and emit it onto the liquid crystal panel 100, and the ability to convert the polarization state of light emitted from the liquid crystal panel 100 from the desired polarized light into linearly polarized light and emit it.

[0043] Furthermore, the structures contained in the optical modulation module 4 do not need to be physically connected or integrally formed. Even if the structures or parts thereof are physically separated, it is sufficient as long as there is an electrical or optical relationship between them.

[0044] The projection display device 1000 has three laser light sources 200R, 200G, and 200B corresponding to RGB as light sources, three liquid crystal devices 1R, 1G, and 1B corresponding to RGB as image display devices, and a projection optical system 300.

[0045] Laser source 200R emits red light. The central wavelength λ of the red light is 610 nm. Laser source 200G emits green light. The central wavelength λ of the green light is 550 nm. Laser source 200B emits blue light. The central wavelength λ of the blue light is 455 nm.

[0046] Liquid crystal devices 1R, 1G, and 1B each have a first polarizing plate 51 as a first polarizing element, a first phase difference control element 60 as a first phase difference adjustment element, a liquid crystal panel 100, a second phase difference control element 70 as a second phase difference adjustment element, and a second polarizing plate 52 as a second polarizing element. Furthermore, regarding the first polarizing plate 51, when the light emitted from the laser light sources 200R, 200G, and 200B is linearly polarized, the first polarizing plate 51 can be omitted. When the linearly polarized light emitted from the laser light sources 200R, 200G, and 200B is directly incident on the first phase difference control element 60, the laser light sources 200R, 200G, and 200B correspond to the first polarizing plate 51.

[0047] The liquid crystal panel 100R of the liquid crystal device 1R modulates red light emitted from the laser light source 200R based on red grayscale data. The liquid crystal panel 100G of the liquid crystal device 1G modulates green light emitted from the laser light source 200G based on green grayscale data. The liquid crystal panel 100B of the liquid crystal device 1B modulates blue light emitted from the laser light source 200B based on blue grayscale data.

[0048] The first polarizing plate 51 adjusts the polarization of the light emitted from the laser source 200R, 200G or laser source 200B, and emits linearly polarized light to the first phase difference control element 60.

[0049] The first phase difference control element 60R of the liquid crystal device 1R is disposed between the first polarizing plate 51 and the liquid crystal panel 100R. Based on the phase difference of the first phase difference control element 60R, the polarization state of the incident linearly polarized light is maintained as linearly polarized light or changed from linearly polarized light to elliptically polarized light or circularly polarized light before being emitted into the liquid crystal panel 100. Furthermore, the phase difference of the first phase difference control element 60R is controlled to be variable within the range of 0 (zero) to λ / 4 by a method described later.

[0050] When the phase difference of the first phase difference control element 60R is controlled to be zero, it emits linearly polarized light incident from the first polarizer 51 with its polarization state almost unchanged. Furthermore, when the phase difference of the first phase difference control element 60R is controlled to be λ / 8, it converts the linearly polarized light incident from the first polarizer 51 into elliptically polarized light for emission. Similarly, when the phase difference is controlled to be λ / 4, the first phase difference control element 60R converts the linearly polarized light into circularly polarized light for emission.

[0051] Furthermore, the first phase difference control element 60G of the liquid crystal device 1G and the first phase difference control element 60B of the liquid crystal device 1B are configured in the same way as the first phase difference control element 60R.

[0052] The second phase difference control element 70R of the liquid crystal device 1R is disposed between the liquid crystal panel 100R and the second polarizing plate 52, and its phase difference is controlled to make the polarization state of the light emitted from the liquid crystal panel 100R linearly polarized light.

[0053] When the phase difference of the first phase difference control element 60R is set to zero, the phase difference of the second phase difference control element 70R is also set to zero, and the second phase difference control element 70R passes through in a manner that keeps the polarization state of the linearly polarized light emitted from the liquid crystal panel 100R unchanged.

[0054] Furthermore, when the phase difference of the first phase difference control element 60R is set to λ / 8, the phase difference of the second phase difference control element 70R is also set to λ / 8, and the second phase difference control element 70R causes the elliptically polarized light emitted from the liquid crystal panel 100R to be converted into linearly polarized light before being emitted. Similarly, when the phase difference of the first phase difference control element 60R is set to λ / 4, the phase difference of the second phase difference control element 70R is also set to λ / 4, and the second phase difference control element 70R causes the circularly polarized light emitted from the liquid crystal panel 100R to be converted into linearly polarized light before being emitted.

[0055] Furthermore, the second phase difference control element 70G of the liquid crystal device 1G and the second phase difference control element 70B of the liquid crystal device 1B are configured in the same way as the second phase difference control element 70R.

[0056] The second polarizer 52 polarizes the light emitted from the second phase difference control element 70 and causes it to be incident on the dichroic prism 310.

[0057] The dichroic prism 310 combines the light emitted from the liquid crystal panel 100R, the light emitted from the liquid crystal panel 100G, and the light emitted from the liquid crystal panel 100B.

[0058] The projection lens 330 magnifies the light emitted from the dichroic prism 310 and projects it onto the projection surface 510 of the screen 500.

[0059] The liquid crystal device 1R includes an image processing unit 80, a phase difference adjustment unit 90, and a brightness detection unit 95. Alternatively, the image processing unit 80, phase difference adjustment unit 90, and brightness detection unit 95 can be shared by all liquid crystal devices 1R, 1G, and 1B, but they can also be configured such that each liquid crystal device 1R, 1G, and 1B has its own image processing unit 80, phase difference adjustment unit 90, and brightness detection unit 95.

[0060] The image processing unit 80 provides grayscale data for each color to the liquid crystal panels 100R, 100G, and 100B based on the image data. Furthermore, the image processing unit 80 analyzes the image data and outputs the analysis information to the phase difference adjustment unit 90. In this embodiment, the analysis information is, for example, average grayscale information or contrast information. However, the analysis information is not limited to these; it can also be content information such as movie, sports, game, landscape, text, moving images, or still images.

[0061] The brightness detection unit 95 detects the brightness of the area where the screen 500 is installed and outputs the detected brightness information to the phase difference adjustment unit 90.

[0062] The phase difference adjustment unit 90 outputs phase difference control signals RcR, RcG, and RcB to control the phase difference between the first phase difference control elements 60R, 60G, 60B and the second phase difference control elements 70R, 70G, 70B, based on the analysis information from the image processing unit 80 and / or the brightness information from the brightness detection unit 95.

[0063] Alternatively, the first phase difference control element 60 and the second phase difference control element 70 may be configured to be provided only in one or two of the liquid crystal devices 1R, 1G, and 1B. For example, the first phase difference control element 60G, 60R and the second phase difference control element 70G, 70B may be provided only in the liquid crystal device 1G or the liquid crystal devices 1G and 1R that correspond only to green light, which is easily noticeable due to display defects based on the reverse deflection region, or to green light and red light, while the first phase difference control element 60B and the second phase difference control element 70B are not provided in the liquid crystal device 1B that corresponds to blue light, which is not easily noticeable due to display defects based on the reverse deflection region.

[0064] 1.2. Overview of LCD panels combined with optical modulation modules

[0065] Figure 2 This is a top view showing the schematic structure of the liquid crystal panel combined with the light modulation module, indicating the view of the liquid crystal panel 100 along the Z2 direction. Furthermore, liquid crystal panels 100R, 100G, and 100B are constructed in the same manner as liquid crystal panel 100.

[0066] In this embodiment, the liquid crystal panel 100 will be described as an active-drive type liquid crystal panel in which each pixel is equipped with a TFT (Thin Fiber Transistor) as a pixel transistor.

[0067] In the liquid crystal panel 100, a light-transmitting first substrate 10 and a light-transmitting second substrate 20 are bonded together by a sealing material 107 with a predetermined gap. The sealing material 107 is arranged in a frame shape along the outer edge of the second substrate 20, and a liquid crystal layer 5, which serves as a first liquid crystal layer, is disposed in the area surrounded by the sealing material 107 between the first substrate 10 and the second substrate 20.

[0068] In the liquid crystal panel 100, both the first substrate 10 and the second substrate 20 are quadrilaterals. At approximately the center of the liquid crystal panel 100, a display area 10a is set as a rectangular area whose dimensions in the 3 o'clock (III) to 9 o'clock (IX) direction of the analog clock are longer than those in the 12 o'clock (XII) to 6 o'clock (VI) direction of the analog clock. The display area 10a is surrounded by a peripheral area 10b. Furthermore, the 3 o'clock (III) to 9 o'clock (IX) direction of the analog clock is along the X-axis, and the 12 o'clock (XII) to 6 o'clock (VI) direction of the analog clock is along the Y-axis.

[0069] A rectangular frame-shaped peripheral region 10b is provided between the display area 10a and the outer periphery of the second substrate 20. The sealing material 107 is provided in a generally rectangular frame shape in the peripheral region 10b.

[0070] On the second substrate 20 side of the first substrate 10, a data line driving circuit 101, a plurality of terminals 102 and a scan line driving circuit 104 are arranged on the outer side of the display area 10a.

[0071] Terminal 102 is connected to flexible wiring substrate 105, and various potentials and signals are input to the first substrate 10 via flexible wiring substrate 105.

[0072] The second substrate 20 has a light-shielding film 28 made of a metal compound or the like. The light-shielding film 28 is, for example, a separator 28a disposed along the outer periphery of the display area 10a.

[0073] On the first substrate 10, in a region that is outside the seal 107 and overlaps with the corner portion of the second substrate 20, an inter-substrate conductive electrode 106 is formed for achieving electrical conduction between the first substrate 10 and the second substrate 20.

[0074] in addition, Figure 2 The direction P shown represents the orientation direction of the liquid crystal molecules 5a of the liquid crystal layer 5. In this embodiment, the orientation direction P is from the direction of 1:30 on the analog clock face towards 7:30 when viewed from above.

[0075] 1.3. Overview of the Optical Modulation Module

[0076] Figure 3 This is a schematic cross-sectional view showing the optical modulation module of this embodiment.

[0077] The liquid crystal device 1 includes a first polarizer 51, a first phase difference control element 60, a liquid crystal panel 100, a second phase difference control element 70, and a second polarizer 52 arranged sequentially from the incident side of the light L emitted from the laser light source 200. Furthermore, liquid crystal devices 1R, 1G, and 1B are configured similarly to liquid crystal device 1.

[0078] In the display area 10a of the first substrate 10 of the liquid crystal panel 100, a plurality of light-transmitting pixel electrodes 9a, composed of a light-transmitting conductive film such as ITO (Indium Tin Oxide) film, and pixel switching elements 30 electrically connected to the plurality of pixel electrodes 9a are arranged in a matrix. In addition, light-shielding wirings 8 and 17 are provided between the plurality of insulating films 13 stacked between the substrate body 19 and the pixel electrodes 9a. A first alignment film 16 composed of an inorganic obliquely vapor-deposited film is formed on the second substrate 20 side relative to the pixel electrodes 9a, and the pixel electrodes 9a are covered by the first alignment film 16.

[0079] A dummy pixel electrode 9b is formed in the peripheral region 10b of the first substrate 10. In this embodiment, the first substrate 10 includes a structure extending from the substrate body 19 to the first alignment film 16.

[0080] The second substrate 20 has a substrate body 29 that is transparent to light, such as quartz or glass. A transparent common electrode 21, made of an ITO film or the like, is formed on approximately the entire surface of the second substrate 20 on the side of the first substrate 10. A second alignment film 26, made of an inorganic obliquely deposited film, is disposed between the common electrode 21 and the liquid crystal layer 5.

[0081] The separator 28a is disposed on the side opposite to the first substrate 10, between the common electrode 21 and the protective layer 24 in the peripheral region 10b. Furthermore, the separator 28a overlaps with the dummy pixel electrode 9b of the first substrate 10 when viewed from above. In this embodiment, the second substrate 20 includes a structure extending from the substrate body 29 to the second alignment film 26.

[0082] The liquid crystal panel 100 is configured such that liquid crystal molecules 5a with negative dielectric anisotropy are sandwiched between the first substrate 10 and the second substrate 20 in a VA (Vertical Alignment) mode by a sealing material 107. In this liquid crystal panel 100, if a voltage is applied between the pixel electrode 9a and the common electrode 21, the liquid crystal molecules 5a of the liquid crystal layer 5 are displaced along the alignment direction P in a direction in which the tilt angle relative to the first substrate 10 and the second substrate 20 decreases.

[0083] The first phase difference control element 60 and the second phase difference control element 70 are the same as the liquid crystal panel 100, both being VA mode liquid crystal panels.

[0084] The first phase difference control element 60 has a fourth substrate 62 disposed on the incident side of light L and a third substrate 61 disposed on the emission side, and a liquid crystal layer 67 having negative dielectric anisotropy as a second liquid crystal layer is sandwiched between the third substrate 61 and the fourth substrate 62 bonded by sealing material 108.

[0085] The third substrate 61 includes an electrode 63, and the fourth substrate 62 includes an electrode 64. A third alignment film 65, which is an inorganic obliquely vapor-deposited film and serves as a first emission-side alignment film, is disposed between the electrode 63 of the third substrate 61 and the liquid crystal layer 67. A fourth alignment film 66, which is an inorganic obliquely vapor-deposited film and serves as a first incident-side alignment film, is disposed between the electrode 64 of the fourth substrate 62 and the liquid crystal layer 67. The third alignment film 65 and the fourth alignment film 66 align the liquid crystal molecules 67a of the liquid crystal layer 67 along the first direction described later.

[0086] The second phase difference control element 70 has a sixth substrate 72 disposed on the incident side of light L and a fifth substrate 71 disposed on the emission side, and a liquid crystal layer 77 having negative dielectric anisotropy as a third liquid crystal layer is sandwiched between the fifth substrate 71 and the sixth substrate 72 bonded by sealing material 109.

[0087] The thicknesses d2 and d3 of liquid crystal layer 67 are preferably less than or equal to the thickness d1 of liquid crystal layer 5 of liquid crystal panel 100. The thickness d2 of liquid crystal layer 67 is affected by the in-plane deviation of the cell gap of the first phase difference control element 60, resulting in an in-plane phase difference deviation when voltage is applied. Therefore, the thicker the thickness d2 of liquid crystal layer 67, the better it can suppress transmittance variations caused by in-plane cell gap deviations relative to a specified voltage. On the other hand, if the thickness d2 of liquid crystal layer 67 is increased, the phase difference also increases accordingly, deteriorating the contrast. The same applies to the thickness d3 of liquid crystal layer 77.

[0088] Therefore, in this embodiment, the thickness d2 of the liquid crystal layer 67 and the thickness d3 of the liquid crystal layer 77 are respectively less than or equal to the thickness d1 of the liquid crystal layer 5 of the liquid crystal panel 100.

[0089] The birefringence Δn2 of the liquid crystal material used for liquid crystal layer 67 is preferably less than the birefringence Δn1 of the liquid crystal material used for liquid crystal layer 5 of liquid crystal panel 100.

[0090] Liquid crystals with a smaller birefringence Δn have a longer lightfastness lifespan compared to liquid crystals with a larger birefringence Δn. Therefore, by making the birefringence Δn2 of the liquid crystal material used in the first phase difference control element 60 disposed on the light incident side of the liquid crystal panel 100 smaller than Δn1 of the liquid crystal material used in the liquid crystal panel 100, it is possible to prevent the lightfastness lifespan of the first phase difference control element 60 from being exhausted before that of the liquid crystal panel 100.

[0091] The birefringence Δn3 of the liquid crystal material used in liquid crystal layer 77 is also preferably lower than the birefringence Δn1 of the liquid crystal material used in liquid crystal layer 5 of liquid crystal panel 100. This prevents the lightfastness lifespan of the second phase difference control element 70 from being depleted before that of liquid crystal panel 100.

[0092] The fifth substrate 71 includes an electrode 73, and the sixth substrate 72 includes an electrode 74. A fifth alignment film 75, which is an inorganic obliquely vapor-deposited film and serves as a second emission-side alignment film, is disposed between the electrode 73 of the fifth substrate 71 and the liquid crystal layer 77. A sixth alignment film 76, which is an inorganic obliquely vapor-deposited film and serves as a second incident-side alignment film, is disposed between the electrode 74 of the sixth substrate 72 and the liquid crystal layer 77. The fifth alignment film 75 and the sixth alignment film 76 align the liquid crystal molecules 77a of the liquid crystal layer 77 along a second direction that intersects with the first direction described later.

[0093] In this embodiment, the third substrate 61, the fourth substrate 62, the fifth substrate 71, and the sixth substrate 72 are configured in the same way as the second substrate 20 of the liquid crystal panel 100. Furthermore, the separator 28a of the second substrate 20 is not a necessary structure in the third substrate 61, the fourth substrate 62, the fifth substrate 71, and the sixth substrate 72.

[0094] Here, by configuring the third substrate 61 and the fifth substrate 71 in the same way as the first substrate 10 of the liquid crystal panel 100 to have pixel electrodes 9a, it is also possible to configure them to control the phase difference for each region corresponding to the size of the pixel electrodes 9a.

[0095] In this case, the electrodes 63 of the third substrate 61 and the electrodes 73 of the fifth substrate 71 are divided into the same shape when viewed from above. For example, when the electrodes 63 of the third substrate 61 are divided into two, the light-transmitting area of ​​the third substrate 61 is divided into two regions: a first light-transmitting region and a second light-transmitting region. By dividing the electrodes 63 into two, different voltage values ​​can be applied to each electrode, thus allowing control of the phase difference between the liquid crystal layer 67 corresponding to the first light-transmitting region and the phase difference between the liquid crystal layer 67 corresponding to the second light-transmitting region. Furthermore, the electrodes 73 of the fifth substrate 71 are also divided into the same shape, and the light-transmitting area of ​​the fifth substrate 71 is divided into two regions: a third light-transmitting region corresponding to the first light-transmitting region and a fourth light-transmitting region corresponding to the second light-transmitting region. By dividing the electrode 73 into several parts, different voltage values ​​can be applied to each electrode. However, in this embodiment, the third light-transmitting region is controlled to have the same or approximately the same phase difference as the first light-transmitting region, and the fourth light-transmitting region is controlled to have the same or approximately the same phase difference as the second light-transmitting region.

[0096] The number of divisions for electrodes 63 and 73 can range from 2 to the same number as pixel electrode 9a. The more divisions, the finer the phase difference can be controlled. Furthermore, since reverse deflection regions sometimes occur in two or more consecutive pixels, the number of divisions for electrodes 63 and 73 can be set to be less than the number of pixel electrodes 9a.

[0097] In the first phase difference control element 60 and the second phase difference control element 70, when no voltage is applied between the electrodes 63 and 64 driving the liquid crystal layer 67 and between the electrodes 73 and 74 driving the liquid crystal layer 77, the liquid crystal molecules 67a and 77a of the liquid crystal layers 67 and 77 are vertically aligned relative to the substrate surface. In this case, the phase difference between the first phase difference control element 60 and the second phase difference control element 70 is zero, and the first phase difference control element 60 and the second phase difference control element 70 allow incident light to pass through without changing its polarization state.

[0098] Furthermore, regarding the phase difference between the first phase difference control element 60 and the second phase difference control element 70, as described later, the liquid crystal molecules 5a are pre-tilted, so strictly speaking, it will not be zero. Therefore, in this embodiment, the statement that the phase difference between the first phase difference control element 60 and the second phase difference control element 70 is zero means that there is no applied voltage in the initial alignment state of the liquid crystal layer 67 and the liquid crystal layer 77.

[0099] On the other hand, in the first phase difference control element 60 and the second phase difference control element 70, if a voltage is applied between electrodes 63 and 64 and between electrodes 73 and 74, and the applied voltage value is increased, the liquid crystal molecules 67a and 77a of the liquid crystal layers 67 and 77 gradually tilt in a direction parallel to the substrate surface, and the phase difference between the first phase difference control element 60 and the second phase difference control element 70 gradually increases.

[0100] The first phase difference control element 60 is configured such that its slow axis is at a 45° angle relative to the polarization axis of the first polarizer 51, and the second phase difference control element 70 is configured such that its slow axis is at a 45° angle relative to the polarization axis of the second polarizer 52. That is, the first phase difference control element 60 and the second phase difference control element 70 are configured with their respective slow axes orthogonal.

[0101] The first polarizer 51 and the second polarizer 52 are configured in an orthogonal Nicol configuration with their polarization axes at an angle of 90° to each other. The liquid crystal panel 100 is configured such that the orientation direction P of the liquid crystal molecules 5a is at an angle of 45° relative to the polarization axes of the first polarizer 51 and the second polarizer 52.

[0102] In this embodiment, the slow axis of the first phase difference control element 60 is configured to be parallel to the orientation direction P of the liquid crystal panel 100, and the slow axis of the second phase difference control element 70 is configured to be orthogonal to the orientation direction P of the liquid crystal panel 100.

[0103] In the first phase difference control element 60 and the second phase difference control element 70, the orientation direction of the liquid crystal molecules 67a and 77a in the liquid crystal layers 67 and 77 is the direction of the slow axis. Therefore, in this embodiment, the orientation direction of the liquid crystal molecules 67a in the liquid crystal layer 67, i.e., the first direction, is parallel to the orientation direction P, and the orientation direction of the liquid crystal molecules 77a in the liquid crystal layer 77, i.e., the second direction, is orthogonal to the orientation direction P.

[0104] Alternatively, the slow axis of the first phase difference control element 60 can be configured to be orthogonal to the orientation direction P of the liquid crystal panel 100, and the slow axis of the second phase difference control element 70 can be parallel to the orientation direction P of the liquid crystal panel 100. In this case, the first direction is orthogonal to the orientation direction P, and the second direction is parallel to the orientation direction P.

[0105] With this configuration, the first phase difference control element 60 and the second phase difference control element 70 control the voltage applied to the liquid crystal layers 67 and 77, and control the phase difference of the liquid crystal layers 67 and 77 to the desired value. This enables the polarization state of the light incident on the first phase difference control element 60 and the second phase difference control element 70 to not change from linearly polarized light, or to change from linearly polarized light to elliptically polarized light or circularly polarized light, or to change from elliptically polarized light or circularly polarized light to linearly polarized light.

[0106] Furthermore, the angle between the polarization axis of the first polarizing plate 51 and the polarization axis of the second polarizing plate 52, the angle between the slow axis of the first phase difference control element 60 and the slow axis of the second phase difference control element 70, and the angle between the slow axis of the second phase difference control element 70 or the first phase difference control element 60 and the orientation direction P are not limited to 90°. Considering manufacturing tolerances, the angle can be within the range of 90°±5°.

[0107] Furthermore, the angles formed by the polarization axes of the first polarizing plate 51 and the second polarizing plate 52 with the orientation direction P, the angles formed by the slow axis of the first phase difference control element 60 with the polarization axis of the first polarizing plate 51, and the angles formed by the slow axis of the second phase difference control element 70 with the second polarizing plate 52 are not limited to 45°. Considering manufacturing tolerances, the angles can be within the range of 45°±5°.

[0108] Furthermore, the angle between the slow axis of the first phase difference control element 60 or the second phase difference control element 70 and the orientation direction P is not limited to 0°. Considering manufacturing tolerances, the angle can be within the range of 0°±5°.

[0109] In this embodiment, the liquid crystal panel 100 and the first phase difference control element 60 are configured as separate structures, but they can also be configured as an integral structure. In this case, for example, the third substrate 61 can be formed on the substrate body 29. Similarly, the liquid crystal panel 100 and the second phase difference control element 70 can also be configured as an integral structure. In this case, for example, the sixth substrate 72 can be formed on the substrate body 19.

[0110] In this embodiment, both the first phase difference control element 60 and the second phase difference control element 70 employ a VA mode liquid crystal panel, but this is not a limitation. For example, a liquid crystal panel of the following type can also be used: in a state where no voltage is applied to the liquid crystal layer, i.e., in the initial alignment state, the liquid crystal molecules are aligned in a manner parallel to the substrate, and by applying a voltage to the liquid crystal layer, the liquid crystal molecules are aligned in a direction perpendicular to the substrate. As a liquid crystal panel that performs such an operation, an ECB mode (Electrically Controlled Birefringence) liquid crystal panel can be used.

[0111] 1.4. Overview of the structure of the liquid crystal layer

[0112] Figure 4 This is an explanatory diagram schematically illustrating the structure of the liquid crystal layer in an LCD panel.

[0113] The first alignment film 16 and the second alignment film 26 of the liquid crystal panel 100 are composed of columnar structure layers, which are columnar bodies 16a and 26a, referred to as columns, formed obliquely relative to the substrate bodies 19 and 29. Therefore, the first alignment film 16 and the second alignment film 26 obliquely align the liquid crystal molecules 5a relative to the first substrate 10 and the second substrate 20, thus imparting a pre-tilt to the liquid crystal molecules 5a.

[0114] Here, in the OFF state where no voltage is applied between the pixel electrode 9a and the common electrode 21, the angle formed by the direction perpendicular to the first substrate 10 and the second substrate 20 and the long axis direction of the liquid crystal molecule 5a, i.e., the orientation direction P, is the pretilt angle θp. In this embodiment, the pretilt angle θp is, for example, 5°.

[0115] With a voltage applied between the pixel electrode 9a and the common electrode 21 in the ON state, the liquid crystal molecule 5a moves along the alignment direction P, as shown by the dashed line, in a manner that the tilt angle relative to the first substrate 10 and the second substrate 20 decreases. This alignment direction P is the so-called viewing direction.

[0116] The liquid crystal layers 67 and 77 of the first phase difference control element 60 and the second phase difference control element 70 are also constructed in the same way as the liquid crystal panel 100.

[0117] 1.5. Overview of linear polarization modes and elliptical or circular polarization modes

[0118] Figure 5A , Figure 5B These are illustrations of Mode 1. In Mode 1, the phase difference between the first phase difference control element 60 and the second phase difference control element 70 is controlled to be zero. Figure 5A This indicates an OFF state where no voltage is applied between the pixel electrode 9a and the common electrode 21 of the liquid crystal panel 100. Figure 5B This indicates an ON state, meaning a voltage has been applied between the pixel electrode 9a and the common electrode 21 of the liquid crystal panel 100.

[0119] Figure 6A , Figure 6B These are illustrations of the second mode. In the second mode, the phase difference between the first phase difference control element 60 and the second phase difference control element 70 is controlled, for example, to any one of λ / 24, λ / 12, λ / 8, λ / 6, or λ / 4. Figure 6A This indicates an OFF state where no voltage is applied between the pixel electrode 9a and the common electrode 21 of the liquid crystal panel 100. Figure 6B This indicates an ON state, meaning a voltage has been applied between the pixel electrode 9a and the common electrode 21 of the liquid crystal panel 100.

[0120] exist Figure 5A , Figure 5B and Figure 6A , Figure 6B In the diagram, dashed arrows represent the polarization axis of the first polarizing plate 51, the slow axis of the first phase difference control element 60, the orientation direction P of the liquid crystal molecules 5a in the liquid crystal panel 100, the slow axis of the second phase difference control element 70, and the polarization axis of the first polarizing plate 51, respectively, while solid arrows represent the polarization state of light.

[0121] In this embodiment, the orientation direction P of the liquid crystal molecules 5a in the liquid crystal panel 100 is parallel to the slow axis of the first phase difference control element 60, and the slow axis of the first phase difference control element 60 is orthogonal to the slow axis of the second phase difference control element 70.

[0122] In this embodiment, the phase difference R between the first phase difference control element 60 and the second phase difference control element 70 is controlled to be a value in the range of zero to λ / 4 when the wavelength of the incident light to the liquid crystal panel 100 is λ.

[0123] In addition, the first phase difference control element 60 and the second phase difference control element 70 are controlled to have the same phase difference.

[0124] Next, refer to Figure 5A , Figure 5B The phase difference between the first phase difference control element 60 and the second phase difference control element 70 in the first mode will be explained.

[0125] When the phase difference between the first phase difference control element 60 and the second phase difference control element 70 is zero, such as Figure 5A , Figure 5B As shown, the first linearly polarized light L1 emitted from the first polarizing plate 51 passes through the first phase difference control element 60 with its original polarization state and is incident on the liquid crystal panel 100 as the first linearly polarized light L1a.

[0126] like Figure 5A As shown, when the pixels of the liquid crystal panel 100 are in the OFF state corresponding to black, the first linearly polarized light L1b emitted from the liquid crystal panel 100 is emitted from the second phase difference control element 70 with its original polarization state. Therefore, the first linearly polarized light L1c emitted from the second phase difference control element 70 does not exit from the second polarizing plate 52.

[0127] In contrast, such as Figure 5B As shown, when the pixels of the liquid crystal panel 100 are in the ON state corresponding to white display, the second linearly polarized light L2b is emitted from the liquid crystal panel 100. The second linearly polarized light L2b passes through the second phase difference control element 70 with its original polarization state, and is incident on the second polarizing plate 52 as the second linearly polarized light L2c, and is emitted as the second linearly polarized light L2d.

[0128] The amount of light I emitted from the second linearly polarized light L2d emitted from the second polarizing plate 52 is expressed by the following formula.

[0129] I=I0·sin2(2θ)·sin2(n·Δnd / λ)··Formula (1)

[0130] I0 = Incident light intensity

[0131] θ = the angle between the orientation direction P of the liquid crystal layer 5 and the polarization axis of the first polarizer 51.

[0132] n = refractive index of liquid crystal layer 5

[0133] Δnd = Retardation of liquid crystal layer 5

[0134] Δn = birefringence

[0135] d = unit gap

[0136] λ = wavelength of incident light

[0137] Therefore, the emitted light quantity I is affected by the angle θ between the orientation direction P of the liquid crystal layer 5 and the polarization axis of the first polarizer 51. Here, the polarization axis of the polarizer corresponds to the optical axis direction of the first linearly polarized light L1a incident on the liquid crystal panel 100. Therefore, if the orientation of the liquid crystal molecules 5a is disordered due to the transverse electric field, its influence affects the emitted light quantity I, resulting in the generation of black areas in a white screen.

[0138] Next, refer to Figure 6A , Figure 6B The phase difference between the first phase difference control element 60 and the second phase difference control element 70 in the second mode will be explained.

[0139] When the phase difference between the first phase difference control element 60 and the second phase difference control element 70 is set to λ / 4, when the first linearly polarized light L1 is incident on the first phase difference control element 60 at an angle of θ = +45° relative to the slow axis of the first phase difference control element 60, the emitted light from the first phase difference control element 60 becomes right-handed circularly polarized light L3a. Conversely, when the vibration direction of the first linearly polarized light L1 forms an angle of θ = -45° with the slow axis of the first phase difference control element 60, it becomes left-handed circularly polarized light L3a.

[0140] In this embodiment, such as Figure 6A As shown, in the liquid crystal panel 100, the first linearly polarized light L1 emitted from the first polarizing plate 51 is incident on the first phase difference control element 60, and the right-hand circularly polarized light L3a is incident on the liquid crystal panel 100.

[0141] Here, when the pixels of the liquid crystal panel 100 are in the OFF state corresponding to black display, right-handed circularly polarized light L3b is emitted from the liquid crystal panel 100. As a result, the right-handed circularly polarized light L3b is incident on the second phase difference control element 70. Therefore, light of the first linearly polarized light L1c is emitted from the second phase difference control element 70, and thus display light is not emitted from the second polarizing plate 52.

[0142] In contrast, such as Figure 6B As shown, when the pixels of the liquid crystal panel 100 are in the ON state corresponding to white display, left-handed circularly polarized light L4b is emitted from the liquid crystal panel 100, and the left-handed circularly polarized light is incident on the second phase difference control element 70. Therefore, second linearly polarized light L2c is emitted from the second phase difference control element 70, and the second linearly polarized light L2c passes through the second polarizing plate 52 and is emitted as second linearly polarized light L2d.

[0143] Here, when the light incident on the liquid crystal panel 100 is circularly polarized light L3a, since the sin2(2θ) term in equation (1) is absent, the emitted light quantity I is expressed by the following equation. Therefore, even if the orientation of the liquid crystal molecules 5a is disordered due to the transverse electric field, its effect will not affect the emitted light quantity I, thus suppressing the generation of black portions on the white screen. Therefore, if the phase difference between the first phase difference control element 60 and the second phase difference control element 70 is set to λ / 4, the effect of orientation defects caused by the reverse deflection region can be suppressed to the greatest extent.

[0144] I=I0·sin2(n·Δnd / λ)··Formula (2)

[0145] However, when the light incident on the liquid crystal panel 100 is circularly polarized light L3a, the circularly polarized light L3a incident on the liquid crystal panel 100 is prone to light leakage due to phase changes when reflected by the sides of the wiring 8, 17, etc., which can easily reduce the contrast.

[0146] Figure 7 This is a graph showing the relationship between the phase difference of the phase difference control element and the display quality of the image. The horizontal axis is the contrast ratio, showing that the contrast on the right side of the graph is higher than that on the left. The vertical axis is the degree of display defects, showing that the effect of orientation defects is greater on the upper side of the graph than on the lower side.

[0147] Figure 7 This indicates the effect on the display defects and contrast changes of the liquid crystal panel 100 when the phase difference between the first phase difference control element 60 and the second phase difference control element 70 changes from zero to λ / 4.

[0148] When the phase difference between the first phase difference control element 60 and the second phase difference control element 70 is controlled to zero, that is, when the linear polarization mode is set as the first mode, although the reduction in display quality caused by misalignment is not improved, a high-contrast image can be displayed.

[0149] Furthermore, when the phase difference between the first phase difference control element 60 and the second phase difference control element 70 is controlled to be close to λ / 4, that is, when it is set as an elliptical polarization or circular polarization mode as the second mode, the contrast will decrease, but the reduction in display quality caused by poor orientation will be improved.

[0150] In this embodiment, the phase difference R between the first phase difference control element 60 and the second phase difference control element 70 is set to a value in the range of zero or higher to λ / 4, based on the image data to be displayed or the brightness of the room where the display is to be made.

[0151] 1.6. Overview of Phase Difference Control

[0152] Figure 8 This is a functional block diagram representing the structure related to phase difference control.

[0153] The image processing unit 80 includes a frame memory 81, an image signal output unit 82, a histogram generation unit 83, and an arithmetic unit 84. The frame memory 81 stores one frame of image data based on the input image signal Vs. The image signal output unit 82 outputs a red image signal VsR to the liquid crystal panel 100R, a green image signal VsG to the liquid crystal panel 100G, and a blue image signal VsB to the liquid crystal panel 100B, based on the input image signal Vs.

[0154] The histogram generation unit 83 generates a luminance histogram based on the image data of one frame stored in the frame memory 81. The calculation unit 84 calculates the average grayscale of the displayed frame based on the generated luminance histogram and outputs average grayscale information K. Furthermore, the calculation unit 84 can also calculate and output the contrast of the displayed frame based on the generated luminance histogram, as described later.

[0155] The phase difference adjustment unit 90 includes a phase difference determination unit 91 and a phase difference control signal output unit 92.

[0156] The phase difference determination unit 91 determines the phase difference between the first phase difference control elements 60R, 60G, 60B and the second phase difference control elements 70R, 70G, 70B based on the average grayscale information K of one frame of the display image output from the arithmetic unit 84 of the image processing unit 80. The phase difference adjustment unit 90 includes a table that establishes a correspondence between the average grayscale information K and the phase difference, and determines the phase difference based on this table.

[0157] The phase difference control signal output unit 92 outputs phase difference control signals RcR, RcG, and RcB to the liquid crystal devices 1R, 1G, and 1B based on the phase difference determined by the phase difference determination unit 91. These signals are used to control the phase difference of each of the first phase difference control elements 60R, 60G, 60B and the second phase difference control elements 70R, 70G, 70B.

[0158] In the liquid crystal device 1G, the phase difference control signal RcG is input to the first phase difference control element drive unit 68 and the second phase difference control element drive unit 78, which serve as control units. Alternatively, the control unit may also include an image processing unit 80 and a histogram generation unit 83. Furthermore, the control unit may also include a brightness detection unit 95.

[0159] The first phase difference control element drive unit 68 controls the phase difference of the first phase difference control element 60G based on the phase difference control signal RcG. The first phase difference control element drive unit 68 controls the voltage applied to the electrodes 63 and 64, so that the phase difference of the liquid crystal layer 67 becomes the phase difference determined by the phase difference determination unit 91.

[0160] The second phase difference control element drive unit 78 controls the phase difference of the second phase difference control element 70G according to the phase difference control signal RcG. The second phase difference control element drive unit 78 controls the voltage applied to the electrodes 73 and 74, so that the phase difference of the liquid crystal layer 77 becomes the phase difference determined by the phase difference determination unit 91.

[0161] Furthermore, the first phase difference control element drive unit 68 and the second phase difference control element drive unit 78 of the liquid crystal device 1R and the liquid crystal device 1B are also configured in the same way as the liquid crystal device 1G.

[0162] The phase difference control signal RcG input to the first phase difference control element drive unit 68 and the second phase difference control element drive unit 78 does not need to be the same signal; they can be different signals in the first phase difference control element drive unit 68 and the second phase difference control element drive unit 78. For example, the phase difference control signal RcG can be adjusted so that the phase difference of the liquid crystal layer 67 is less than the phase difference of the liquid crystal layer 77. Considering the phase difference of the liquid crystal layer 5 when the liquid crystal panel 100 is in black, that is, when no driving voltage is applied to the liquid crystal layer 5, the contrast is improved when the phase difference of the liquid crystal layer 67 of the first phase difference control element 60G is less than the phase difference of the liquid crystal layer 77 of the second phase difference control element 70G.

[0163] Furthermore, if the control is such that the sum of the phase difference of the liquid crystal layer 67 of the first phase difference control element 60G and the phase difference of the liquid crystal layer 5 of the liquid crystal panel 100 when it is in black is the same as the phase difference of the liquid crystal layer 77 of the second phase difference control element 70G, the contrast can be further improved.

[0164] In addition, the phase difference control signals RcR and RcB can be adjusted in the same way as the phase difference control signal RcG.

[0165] The phase difference control signals RcR, RcG, and RcB are adjusted so that the degree of reverse deflection region generated in the liquid crystal panels 100R, 100G, and 100B is the same in the liquid crystal panels 100R, 100G, and 100B.

[0166] Here, when it is desired that the degree of reverse deflection region is the same in liquid crystal panels 100R, 100G, and 100B, the phase difference of the first phase difference control element 60 and the phase difference of the second phase difference control element 70 are controlled to be different phase differences in liquid crystal devices 1R, 1G, and 1B, respectively.

[0167] For example, among LCD panels 100R, 100G, and 100B, with the same cell spacing, the panel corresponding to a longer wavelength color exhibits a greater shift in VT characteristics towards higher voltage. This means that among LCD panels 100R, 100G, and 100B, the maximum brightness voltage for achieving the highest brightness is highest for LCD panel 100R, followed by LCD panel 100G, and lowest for LCD panel 100B. For instance, while the maximum brightness voltage for LCD panel 100G is 4.5V, the maximum brightness voltage for LCD panel 100R is 5.0V, and the maximum brightness voltage for LCD panel 100B is 4.0V. Therefore, regarding the formation of reverse deflection regions during black-and-white display, the LCD panel 100R, with its larger potential difference, experiences the most severe reverse deflection, while the LCD panel 100B experiences the least.

[0168] Therefore, the phase differences of the first phase difference control elements 60R, 60G, 60B and the second phase difference control elements 70R, 70G, 70B are set such that the first phase difference control element 60R and the second phase difference control element 70R of the liquid crystal device 1R have the largest phase difference, and the first phase difference control element 60B and the second phase difference control element 70B of the liquid crystal device 1B have the smallest phase difference.

[0169] For example, when the phase difference between the first phase difference control element 60G and the second phase difference control element 70G of the liquid crystal device 1G is set to λ / 8, the phase difference between the first phase difference control element 60R and the second phase difference control element 70R of the liquid crystal device 1R is set to a phase difference greater than λ / 8, and the phase difference between the first phase difference control element 60B and the second phase difference control element 70B of the liquid crystal device 1B is set to a phase difference less than λ / 8.

[0170] Furthermore, for example, in LCD panels 100R, 100G, and 100B, if a liquid crystal material with a lower birefringence Δn than other panels is used in LCD panel 100B to ensure consistent lightfastness lifespan across all panels, the VT characteristic of LCD panel 100B shifts towards the high-voltage side. Therefore, the maximum brightness voltage of LCD panel 100B becomes the same as that of LCD panel 100R. In this case, the reverse deflection region during black-and-white display is more severe in LCD panel 100B than in LCD panel 100G.

[0171] Therefore, the phase difference of the first phase difference control elements 60R, 60G, 60B and the second phase difference control elements 70R, 70G, 70B is set such that the phase difference of the liquid crystal device 1B is set to be larger than that of the liquid crystal device 1G, and the phase difference of the liquid crystal device 1G is set to be the smallest.

[0172] Furthermore, in order to further improve the lightfastness lifespan of the liquid crystal panel 100B, a liquid crystal material with a smaller birefringence Δn is used. As a result, when the maximum brightness voltage of the liquid crystal panel 100B exceeds the maximum driving voltage, the cell gap of the liquid crystal panel 100B is thickened as a countermeasure. However, by thickening the cell gap, the reverse deflection region of the liquid crystal panel 100B becomes more severe.

[0173] In this case, the phase difference of the first phase difference control elements 60R, 60G, 60B and the second phase difference control elements 70R, 70G, 70B are also set such that the phase difference of the liquid crystal device 1B is set to be larger than that of the liquid crystal device 1G, and the phase difference of the liquid crystal device 1G is set to be the smallest.

[0174] Furthermore, the phase difference control signals RcR, RcG, and RcB can also be adjusted so that the degree of the reverse deflection region generated in the liquid crystal panels 100R, 100G, and 100B is different in each of the liquid crystal panels 100R, 100G, and 100B. For example, control is performed such that the phase difference of the liquid crystal layer 67 of the first phase difference control element 60G and the phase difference of the liquid crystal layer 77 of the second phase difference control element 70G in the liquid crystal panel 100G, which corresponds to the green light that is easily noticeable due to display defects caused by the reverse deflection region and has relatively high visibility, is higher than other phase differences. Specifically, the phase difference between the first phase difference control element 60G and the second phase difference control element 70G of the liquid crystal device 1G is controlled in a second mode, and the phase difference between the first phase difference control elements 60B and 60R and the second phase difference control elements 70B and 70R of the liquid crystal device 1B and the liquid crystal device 1R is controlled in a first mode. Alternatively, the phase difference between the first phase difference control element 60B and the second phase difference control element 70B of the liquid crystal device 1B can be made smaller than the phase difference between the first phase difference control element 60R and the second phase difference control element 70R of the liquid crystal device 1R.

[0175] The panel driving unit 110 drives the liquid crystal panel 100G based on the green image signal VsG. Furthermore, the liquid crystal devices 1R and 1B are configured similarly to the liquid crystal device 1G.

[0176] The phase difference determination unit 91 can also determine the phase difference based on the brightness information from the brightness detection unit 95. For example, when the screen 500 is set in a bright environment, the contrast ratio (CR) relative to the displayed image decreases. Therefore, even if the phase difference of the phase difference control element is increased to eliminate display defects caused by the reverse deflection area, it is difficult to produce display back reflection. Therefore, it is also possible to program the system to select only the first mode even when the second mode is selected based on the average grayscale information K.

[0177] The image processing unit 80, phase difference adjustment unit 90, first phase difference control element driving unit 68, second phase difference control element driving unit 78, and panel driving unit 110 can be mounted on a single integrated circuit chip, or they can be divided into multiple chips. Alternatively, the image processing unit 80, phase difference adjustment unit 90, first phase difference control element driving unit 68, second phase difference control element driving unit 78, and panel driving unit 110 can also be mounted on a System On-Chip (SOC) of a projection-type display device 1000, or on a driver IC (Integrated Circuit) driving the liquid crystal panel 100. Alternatively, some functional blocks, such as the image processing unit 80 and phase difference adjustment unit 90, can be mounted on the SOC, while the first phase difference control element driving unit 68, second phase difference control element driving unit 78, and panel driving unit 110 can be mounted on the driver IC. These functional blocks can also be formed on the substrate of the liquid crystal panel 100.

[0178] Figure 9 This is a flowchart for calculating the phase difference of the phase difference control element based on brightness.

[0179] In step S1, the histogram generation unit 83 generates a histogram of the gray level Pn of each pixel based on the amount of image data of one frame stored in the frame memory 81.

[0180] Figure 10A This is an explanatory diagram illustrating a dark display example, showing a black circle displayed against a dark gray background. Figure 10B yes Figure 10A The brightness histogram of the dark display screen, with the horizontal axis representing grayscale Pn and the vertical axis representing degrees.

[0181] exist Figure 10A In the case of an overall dark display, as shown, the luminance histogram generated based on the grayscale Pn of each pixel in a single frame becomes... Figure 10BAs shown, a histogram with a high degree on the low grayscale side. In such a dark scene, the lateral electric field between adjacent pixels is unlikely to increase, and fewer reverse deflection areas are generated. Furthermore, even if reverse deflection areas do occur, the display defects caused by these areas are difficult for viewers to visually perceive.

[0182] Therefore, in this embodiment, when displaying a dark screen, as described later, the first phase difference control element 60 and the second phase difference control element 70 are controlled to a first mode in which their phase difference is zero.

[0183] Figure 11A This is an explanatory diagram illustrating a bright display example, showing an example of a light gray circle displayed against a bright white background. Figure 11B yes Figure 11A The brightness histogram of the bright display screen, and Figure 10B Similarly, the horizontal axis represents the gray level Pn, and the vertical axis represents the degree.

[0184] exist Figure 11A In the case of a relatively bright overall image as shown, the luminance histogram generated based on the grayscale Pn of each pixel in a single image becomes... Figure 11B As shown, a histogram with a high degree on the high grayscale side. In such a bright image, the lateral electric field between adjacent pixels tends to increase, and reverse deflection areas are also prone to occur. Furthermore, display defects caused by reverse deflection areas are easily visually apparent to viewers.

[0185] Therefore, in this embodiment, when displaying a bright image, as described later, the first phase difference control element 60 and the second phase difference control element 70 are controlled to a second mode with a phase difference of λ / 8, λ / 4, etc.

[0186] exist Figure 9 In the flowchart, in step S2, the calculation unit 84 calculates the average grayscale information K of one frame based on the generated histogram.

[0187] In steps S3, S4, S5, and S6, the phase difference determining unit 91 determines the phase difference between the first phase difference control element 60 and the second phase difference control element 70. In steps S3, S4, S5, and S6, a is 50, b is 100, c is 150, and d is 200. Furthermore, the values ​​of a, b, c, and d are just examples and can be changed appropriately.

[0188] The phase difference determination unit 91 determines the phase difference based on a table that establishes a correspondence between the average grayscale information K and the phase difference.

[0189] In step S7, if it is determined in step S3 that the average grayscale information K is less than a, the phase difference determination unit 91 sets the phase difference to zero.

[0190] In step S8, if it is determined in step S4 that the average grayscale information K is greater than a and less than b, the phase difference determination unit 91 sets the phase difference to λ / 32.

[0191] In step S9, if it is determined in step S5 that the average grayscale information K is greater than b and less than c, the phase difference determination unit 91 sets the phase difference to λ / 16.

[0192] In step S10, if it is determined in step S6 that the average grayscale information K is greater than or equal to c and less than d, the phase difference determination unit 91 sets the phase difference to λ / 8.

[0193] In step S11, if it is determined in step S6 that the average grayscale information K is greater than or equal to d, the phase difference determination unit 91 sets the phase difference to λ / 4.

[0194] The phase difference determination unit 91 controls the liquid crystal devices 1R, 1G, and 1B respectively to make the phase difference of the first phase difference control element 60 the same as the phase difference of the second phase difference control element 70. Furthermore, the phase difference can also be corrected based on individual differences between the first phase difference control element 60 and the second phase difference control element 70.

[0195] In step S12, the phase difference control signal output unit 92 outputs phase difference control signals RcR, RcG, and RcB to the first phase difference control elements 60R, 60G, 60B and the second phase difference control elements 70R, 70G, 70B of the liquid crystal devices 1R, 1G, 1B based on the phase difference determined by the phase difference determination unit 91.

[0196] The liquid crystal device 1R, based on the phase difference control signal RcR, applies the voltage driving the liquid crystal layer 67 of the first phase difference control element 60R and the liquid crystal layer 77 of the second phase difference control element 70R to the electrodes 63 and 64 of the first phase difference control element 60R and the electrodes 73 and 74 of the second phase difference control element 70R. This changes the orientation direction of the liquid crystal molecules 67a in the liquid crystal layer 67 and the liquid crystal molecules 77a in the liquid crystal layer 77 to a desired direction between a direction perpendicular to and parallel to the substrate surface. Thus, the phase differences of the first phase difference control element 60R and the second phase difference control element 70R are controlled.

[0197] Similarly, the liquid crystal device 1G controls the phase differences of the first phase difference control element 60G and the second phase difference control element 70G based on the phase difference control signal RcG. The liquid crystal device 1B controls the phase differences of the first phase difference control element 60B and the second phase difference control element 70B based on the phase difference control signal RcB.

[0198] In step S7, when the phase difference is zero, the first phase difference control elements 60R, 60G, 60B and the second phase difference control elements 70R, 70G, 70B become the linear polarization mode as the first mode. The phase differences of the first phase difference control elements 60R, 60G, 60B and the phase differences of the second phase difference control elements 70R, 70G, 70B are controlled so that the polarization state of the incident linearly polarized light is maintained and emitted without changing the polarization state of the incident linearly polarized light.

[0199] exist Figure 10B In darker scenes, selecting Mode 1 prioritizes contrast. In dark scenes, the lateral electric field between pixels is less likely to increase, suppressing the formation of reverse deflection areas. Even if reverse deflection areas do occur, the effect of poor orientation is difficult to visually confirm. Therefore, by controlling the phase differences of the first phase difference control elements 60R, 60G, and 60B and the phase differences of the second phase difference control elements 70R, 70G, and 70B to Mode 1, prioritizing contrast, the perceived display quality can be improved.

[0200] In steps S8 to S11, the second mode is entered. The first phase difference control elements 60R, 60G, and 60B convert the incident linearly polarized light into elliptically polarized or circularly polarized light based on the phase difference, and then emit it. The second phase difference control elements 70R, 70G, and 70B convert the incident elliptically polarized or circularly polarized light into linearly polarized light based on the phase difference, and then emit it. Furthermore, the first phase difference control elements 60R, 60G, and 60B emit elliptically polarized light when the phase difference is λ / 32, λ / 16, and λ / 8, and emit circularly polarized light when the phase difference is λ / 4.

[0201] exist Figure 11B In such bright images, the lateral electric field between pixels increases, making it easier to generate reverse deflection areas. In addition, the effects of misalignment are easily visually identifiable. Therefore, by controlling the phase differences of the first phase difference control elements 60R, 60G, and 60B and the phase differences of the second phase difference control elements 70R, 70G, and 70B to the second mode, prioritizing the improvement of misalignment in the display, the display quality perceived by the viewer can be improved.

[0202] As described above, the liquid crystal device 1, which serves as the light modulation module in this embodiment, can achieve the following effects.

[0203] The liquid crystal device 1 of this embodiment includes: a liquid crystal panel 100 having a liquid crystal layer 5 as a first liquid crystal layer; a first polarizer 51 disposed on the incident surface side of the liquid crystal panel 100; a second polarizer 52 disposed on the emission surface side of the liquid crystal panel 100; a first phase difference control element 60 as a first phase difference adjustment element disposed between the first polarizer 51 and the liquid crystal panel 100, having a liquid crystal layer 67 as a second liquid crystal layer; a second phase difference control element 70 as a second phase difference adjustment element disposed between the liquid crystal panel 100 and the second polarizer 52, having a liquid crystal layer 77 as a third liquid crystal layer; and a first phase difference control element driving unit 68 and a second phase difference control element driving unit 78 as control units, which control the phase difference of the liquid crystal layer 67 and the phase difference of the liquid crystal layer 77.

[0204] Alternatively, the first polarizing element can also be a laser source 200 that emits linearly polarized light. Furthermore, the term "image based on the liquid crystal panel 100" is synonymous with "image data."

[0205] According to this structure, the phase difference of the first phase difference control element 60 and the phase difference of the second phase difference control element 70 can be controlled. Therefore, by controlling the polarization state of the light incident on the liquid crystal panel 100 and the light emitted from the liquid crystal panel 100, display defects caused by the generation of the reverse deflection region can be controlled, thereby improving the display quality when viewed by the audience. Furthermore, a balance can be achieved between the reduction in contrast caused by the improvement of display defects caused by the reverse deflection region and the display quality when viewed by the audience.

[0206] Furthermore, in the liquid crystal device 1 of this embodiment, the first phase difference control element 60 has a fourth alignment film 66 as a first incident-side alignment film and a third alignment film 65 as a first emission-side alignment film, which are arranged sandwiching the liquid crystal layer 67. The fourth alignment film 66 and the third alignment film 65 are inorganic alignment films that align the liquid crystal molecules 67a of the liquid crystal layer 67 in a first direction parallel to the alignment direction P. The second phase difference control element 70 has a sixth alignment film 76 as a second incident-side alignment film and a fifth alignment film 75 as a second emission-side alignment film, which are arranged sandwiching the liquid crystal layer 77. The sixth alignment film 76 and the fifth alignment film 75 are inorganic alignment films that align the liquid crystal molecules 77a of the liquid crystal layer 77 in a second direction intersecting the first direction.

[0207] According to this structure, the polarization state of light incident on the liquid crystal panel 100 can be changed from linearly polarized light to linearly polarized light or circularly polarized light, and the polarization state of light emitted from the liquid crystal panel 100 can be controlled from linearly polarized light or circularly polarized light to linearly polarized light. Therefore, it is possible to control display defects caused by the generation of reverse deflection areas and improve the display quality when viewers are watching.

[0208] Furthermore, in the liquid crystal device 1 of this embodiment, the light-transmitting region of the first phase difference control element 60 includes a first light-transmitting region and a second light-transmitting region. The voltage value applied to the liquid crystal layer 67 in the first light-transmitting region is different from the voltage value applied to the liquid crystal layer 67 in the second light-transmitting region. The light-transmitting region of the second phase difference control element 70 includes a third light-transmitting region and a fourth light-transmitting region. The voltage value applied to the liquid crystal layer 77 in the third light-transmitting region is different from the voltage value applied to the third liquid crystal layer in the fourth light-transmitting region.

[0209] According to this structure, the polarization state of light incident on the liquid crystal panel 100 can be changed from linearly polarized light to linearly polarized light or circularly polarized light according to each region, and the polarization state of light emitted from the liquid crystal panel 100 can be controlled from linearly polarized light or circularly polarized light to linearly polarized light according to each region. Therefore, it is possible to control the display defects caused by the generation of reverse deflection regions more precisely, and improve the display quality when the viewer is watching.

[0210] Furthermore, in the liquid crystal device 1 of this embodiment, the thickness d2 of the liquid crystal layer 67 is less than or equal to the thickness d1 of the liquid crystal layer 5, and the thickness d3 of the liquid crystal layer 77 is less than or equal to the thickness d1 of the liquid crystal layer 5.

[0211] According to this structure, by setting the thicknesses d2 and d3 of liquid crystal layer 67 and liquid crystal layer 77 to be less than the thickness d1 of liquid crystal layer 5, the deterioration of contrast can be suppressed, thereby improving the display quality when the viewer is watching.

[0212] Furthermore, in the liquid crystal device 1 of this embodiment, the birefringence Δn2 of the liquid crystal material contained in the liquid crystal layer 67 is less than the birefringence Δn1 of the liquid crystal material contained in the liquid crystal layer 5, and the birefringence Δn3 of the liquid crystal material contained in the liquid crystal layer 77 is less than the birefringence Δn1 of the liquid crystal material contained in the liquid crystal layer 5.

[0213] According to this structure, by making the birefringence of liquid crystal layer 67 and liquid crystal layer 77 less than that of liquid crystal layer 5, the lightfastness lifespan is improved. Therefore, it is possible to avoid the liquid crystals of the first phase difference control element 60 and the second phase difference control element 70 reaching their lifespan before the liquid crystal panel 100 and thus becoming unusable.

[0214] Furthermore, in the liquid crystal device 1 of this embodiment, the first phase difference control element driving unit 68 and the second phase difference control element driving unit 78, which are control units, are controlled such that the phase difference of the first phase difference control element 60 is less than the phase difference of the second phase difference control element 70.

[0215] According to this structure, the phase difference of the first phase difference control element 60 and / or the second phase difference control element 70 can be controlled by taking into account the influence of the phase difference of the liquid crystal panel 100, thereby improving the conversion accuracy when the polarization state of the light emitted from the liquid crystal panel 100 is converted into linearly polarized light.

[0216] Furthermore, in the liquid crystal device 1 of this embodiment, the first phase difference control element driving unit 68 and the second phase difference control element driving unit 78, which are control units, are controlled such that the phase difference of the first phase difference control element 60, which is a first phase difference adjustment element, is greater than the phase difference of the second phase difference control element 70, which is a second phase difference adjustment element.

[0217] According to this structure, the phase difference of the first phase difference control element 60 and / or the second phase difference control element 70 can be controlled by taking into account the influence of the phase difference of the liquid crystal panel 100, thereby improving the conversion accuracy when the polarization state of the light emitted from the liquid crystal panel 100 is converted into linearly polarized light.

[0218] Furthermore, in the liquid crystal device 1 of this embodiment, the first phase difference control element driving unit 68 and the second phase difference control element driving unit 78, which are control units, control the phase difference between the first phase difference control element 60 and the second phase difference control element 70, so that the sum of the phase difference of the first phase difference control element 60 and the phase difference of the liquid crystal panel 100 when it is in black is the same as the phase difference of the second phase difference control element 70.

[0219] According to this structure, the phase difference of the second phase difference control element 70 can be controlled by taking into account the influence of the phase difference of the liquid crystal panel 100, thereby improving the conversion accuracy when the polarization state of the light emitted from the liquid crystal panel 100 is converted into linearly polarized light.

[0220] Furthermore, in the liquid crystal device 1 of this embodiment, the first phase difference control element driving unit 68 and the second phase difference control element driving unit 78, which are control units, control the phase difference between the first phase difference control element 60 and the second phase difference control element 70, so that the sum of the phase difference of the first phase difference control element 60, which is the first phase difference adjustment element, and the phase difference of the liquid crystal panel 100 when it is in black is the same as the sum of the phase difference of the second phase difference control element 70, which is the second phase difference adjustment element.

[0221] According to this structure, the phase difference of the first phase difference control element 60 and / or the second phase difference control element 70 can be controlled by taking into account the influence of the phase difference of the liquid crystal panel 100, thereby improving the conversion accuracy when the polarization state of the light emitted from the liquid crystal panel 100 is converted into linearly polarized light.

[0222] Furthermore, in the liquid crystal device 1 of this embodiment, the first phase difference control element driving unit 68 and the second phase difference control element driving unit 78, which are control units, control the phase difference of the first phase difference control element 60 and the phase difference of the second phase difference control element 70 based on the image data of the image displayed by the liquid crystal panel 100.

[0223] According to this structure, by controlling the display defects caused by the generation of the reverse deflection area based on the displayed image, the display quality when viewed by the viewer can be improved.

[0224] Furthermore, in the liquid crystal device 1 of this embodiment, the first phase difference control element driving unit 68 and the second phase difference control element driving unit 78, which are control units, control the phase difference of the first phase difference control element 60 and the phase difference of the second phase difference control element 70 within the range of 0≤Δnd≤λ / 4.

[0225] According to this structure, the polarization state of light incident on the liquid crystal panel 100 can be changed from linearly polarized light to linearly polarized light or circularly polarized light, and the polarization state of light emitted from the liquid crystal panel 100 can be controlled from linearly polarized light or circularly polarized light to linearly polarized light. Therefore, it is possible to control display defects caused by the generation of reverse deflection areas and improve the display quality when viewers are watching.

[0226] The liquid crystal device 1 of this embodiment includes: a first phase difference control element 60 disposed between a first polarizing plate 51 and a liquid crystal panel 100 having a liquid crystal layer 5; and a second phase difference control element 70 disposed between the liquid crystal panel 100 and a second polarizing plate 52. The first phase difference control element 60 includes: a liquid crystal layer 67; electrodes 63 and 64 that drive the liquid crystal layer 67; and a fourth alignment film 66 and a third alignment film 65 that are disposed sandwiching the liquid crystal layer 67, such that the liquid crystal molecules 67a of the liquid crystal layer 67 are aligned in a first direction parallel to the alignment direction P. The second phase difference control element 70 includes: a liquid crystal layer 77; electrodes 73 and 74 that drive the liquid crystal layer 77; and a sixth alignment film 76 and a fifth alignment film 75 that are disposed sandwiching the liquid crystal layer 77, such that the liquid crystal molecules 77a of the liquid crystal layer 77 are aligned in a second direction intersecting the first direction.

[0227] According to this structure, the polarization state of light incident on the liquid crystal panel 100 can be changed from linearly polarized light to linearly polarized light or circularly polarized light, and the polarization state of light emitted from the liquid crystal panel 100 can be controlled from linearly polarized light or circularly polarized light to linearly polarized light. Therefore, it is possible to control display defects caused by the generation of reverse deflection areas and improve the display quality when viewers are watching.

[0228] The projection-type display device 1000, which is the display device in this embodiment, includes the above-described light modulation module.

[0229] According to this structure, a display device can be provided in which the display defects caused by the generation of the reverse deflection region can be controlled by controlling the polarization state of the light incident on the liquid crystal panel 100 and the light emitted from the liquid crystal panel 100, thereby improving the display quality when the viewer is watching.

[0230] The projection-type display device 1000 of this embodiment includes: a liquid crystal panel 100G serving as a first liquid crystal panel, which modulates light of a first wavelength; and a liquid crystal panel 100B serving as a second liquid crystal panel, which modulates light of a second wavelength different from the first wavelength. The display device also includes: a first phase difference control element 60G disposed on the light incident side of the liquid crystal panel 100G; a second phase difference control element 70G disposed on the light emitting side of the liquid crystal panel 100G; and a phase difference adjustment unit 90 serving as a control unit, which controls the phase difference of the first phase difference control element 60G and the phase difference of the second phase difference control element 70G.

[0231] According to this structure, by controlling the polarization state of the light incident on the liquid crystal panel 100G of the projection display device 1000 and the light emitted from the liquid crystal panel 100G, display defects caused by the generation of the reverse deflection area can be controlled, thereby improving the display quality when the viewer is watching.

[0232] Alternatively, the first and second LCD panels can be replaced with LCD panel 100R and LCD panel 100G, respectively.

[0233] Furthermore, the projection-type display device 1000 of this embodiment includes: a first phase difference control element 60B disposed on the light incident side of the liquid crystal panel 100B as a third phase difference adjustment element; and a second phase difference control element 70B disposed on the light emitting side of the liquid crystal panel 100B as a fourth phase difference adjustment element. The phase difference adjustment unit 90 controls the phase difference of the first phase difference control element 60G and the phase difference of the second phase difference control element 70G of the liquid crystal panel 100B to become a first phase difference, and controls the phase difference of the first phase difference control element 60B and the phase difference of the second phase difference control element 70B of the liquid crystal panel 100B to become a second phase difference different from the first phase difference.

[0234] According to this structure, even if the display defects caused by the reverse deflection area are different in the LCD panel 100G and the LCD panel 100B, the display defects caused by the reverse deflection area can be controlled for each LCD panel, thereby improving the display quality when the viewer is watching.

[0235] Furthermore, in the projection display device 1000 of this embodiment, when the liquid crystal driving voltage at the maximum brightness of the liquid crystal panel 100G is higher than the liquid crystal driving voltage at the maximum brightness of the liquid crystal panel 100B, the phase difference adjustment unit 90 controls the first phase difference to be larger than the second phase difference.

[0236] According to this structure, the phase difference can be controlled based on the degree of generation of the reverse deflection region, thus improving the display quality when viewed by the audience.

[0237] Furthermore, in the projection display device 1000 of this embodiment, the thickness of the liquid crystal layer 5 of the liquid crystal panel 100G is thinner than the thickness of the liquid crystal layer 5 of the liquid crystal panel 100B.

[0238] According to this structure, when the thickness of the liquid crystal layer 5 of each liquid crystal panel is different, the phase difference can be controlled for each liquid crystal panel, thereby improving the display quality when the viewer is watching.

[0239] Furthermore, in the projection display device 1000 of this embodiment, the birefringence Δn of the liquid crystal layer of the liquid crystal panel 100B is smaller than the birefringence Δn of the liquid crystal layer 5 of the liquid crystal panel 100G.

[0240] According to this structure, a liquid crystal material with a small birefringence Δn is used in the liquid crystal layer 5 of the liquid crystal panel 100B corresponding to short-wavelength blue light. Therefore, the light resistance life of the liquid crystal panel 100B can be improved, and the light resistance life of the liquid crystal panel 100B can be made consistent with that of the liquid crystal panel 100G corresponding to green light and the liquid crystal panel 100R corresponding to red light.

[0241] Furthermore, in the projection-type display device 1000 of this embodiment, when the birefringence Δn of the liquid crystal layer 5 of the liquid crystal panel 100B is less than the birefringence Δn of the liquid crystal layer 5 of the liquid crystal panel 100G, the phase difference adjustment unit 90 makes the second phase difference, which is the phase difference between the first phase difference control element 60B and the second phase difference control element 70B of the liquid crystal panel 100B, greater than the first phase difference, which is the phase difference between the first phase difference control element 60G and the second phase difference control element 70G of the liquid crystal panel 100G.

[0242] According to this structure, since a liquid crystal material with a low birefringence Δn is used in the liquid crystal layer 5 of the liquid crystal panel 100B corresponding to short-wavelength blue light, the light resistance life of the liquid crystal panel 100B can be improved. Furthermore, since the first phase difference is made larger than the second phase difference, the degree of display defects caused by the reverse deflection region generated in the liquid crystal panel 100B and the liquid crystal panel 100G can be made consistent in both the liquid crystal panel 100B and the liquid crystal panel 100G.

[0243] Furthermore, the light modulation module 4 includes: a liquid crystal panel 100 having a liquid crystal layer 5 as a first liquid crystal layer; a first polarizer 51 disposed on the light incident side of the liquid crystal panel 100; a second polarizer 52 disposed on the light emitting side of the liquid crystal panel 100; a first phase difference control element 60 as a first phase difference control adjustment element, which is applied with a voltage corresponding to the image displayed on the liquid crystal panel 100, disposed between the first polarizer 51 and the liquid crystal panel 100, and has a liquid crystal layer 67 as a second liquid crystal layer; and a second phase difference control element 70 as a second phase difference adjustment element, which is applied with a voltage corresponding to the image displayed on the liquid crystal panel 100, disposed between the liquid crystal panel 100 and the second polarizer 52, and has a liquid crystal layer 77 as a third liquid crystal layer.

[0244] According to this structure, the polarization state of light incident on the liquid crystal panel 100 can be controlled based on the image displayed by the liquid crystal panel 100, thereby improving the display quality when viewed by the viewer.

[0245] 2. Implementation Method 2

[0246] 2.1. Overview of Phase Difference Control

[0247] Figure 12 This is a flowchart for calculating the phase difference of the phase difference control element based on the contrast ratio.

[0248] In step S21, the histogram generation unit 83 generates a histogram of the gray level Pn of each pixel based on the amount of image data of one frame stored in the frame memory 81.

[0249] Figure 13A This is an explanatory diagram showing an example of a low-contrast display, where the difference in brightness is small across the overall image. Figure 13B yes Figure 13A The brightness histogram of a low-contrast display image, with the horizontal axis representing grayscale Pn and the vertical axis representing degrees.

[0250] exist Figure 13A In the case of an image where the overall brightness difference is small, as shown, the brightness histogram generated based on the grayscale Pn of each pixel in a single image becomes... Figure 13B As shown, this is a histogram with a large convex shape. In such a low-contrast image, the lateral electric field between adjacent pixels is difficult to increase, and fewer inverted areas are generated. Furthermore, even if inverted areas do occur, it is difficult for viewers to visually confirm the display defects caused by these areas.

[0251] Therefore, in this embodiment, when displaying a darker image, as described later, the first phase difference control element 60 and the second phase difference control element 70 are controlled to a first mode in which their phase difference is zero.

[0252] Figure 14A This is an explanatory diagram showing an example of a high-contrast display screen, illustrating an example of a screen with a large difference in brightness between white and black. Figure 14B yes Figure 14A The brightness histogram of a high-contrast display image, and Figure 13B Similarly, the horizontal axis represents the gray level Pn, and the vertical axis represents the degree.

[0253] In display Figure 14A In the case of a bright image as shown, the brightness histogram generated based on the grayscale Pn of each pixel in a single image becomes as follows. Figure 14B As shown, there are large convex histograms at the two separated locations. In such a high-contrast image, the lateral electric field between adjacent pixels tends to increase, and reverse deflection regions are also prone to occur. Furthermore, display defects based on reverse deflection regions are easily visually identifiable by viewers.

[0254] Therefore, in this embodiment, when displaying a high-contrast image, as described later, the first phase difference control element 60 and the second phase difference control element 70 are controlled to a second mode with a phase difference of λ / 8 or λ / 4, etc.

[0255] exist Figure 12 In the flowchart, in step S22, the calculation unit 84 calculates the contrast ratio CR of one frame based on the generated histogram. The contrast ratio CR is calculated, for example, based on the gray-level difference between the two gray levels with the largest degree in the histogram. Furthermore, if there are three or more gray levels with large degree, the contrast ratio CR can be calculated based on the two gray-level differences with the largest gray-level differences.

[0256] In steps S23, S24, S25, and S26, the phase difference determining unit 91 determines the phase difference between the first phase difference control element 60 and the second phase difference control element 70. In steps S23, S24, S25, and S26, a is 500, b is 1000, c is 1500, and d is 2000. Furthermore, the values ​​of a, b, c, and d are just examples and can be appropriately changed.

[0257] The phase difference determination unit 91 determines the phase difference based on a table that establishes a correspondence between the contrast CR and the phase difference.

[0258] In step S27, if it is determined in step S23 that the contrast CR is less than a, the phase difference determination unit 91 sets the phase difference to zero.

[0259] In step S28, if it is determined in step S24 that the contrast ratio CR is a or higher and less than b, the phase difference determination unit 91 sets the phase difference to λ / 32.

[0260] In step S29, if it is determined in step S25 that the contrast ratio CR is greater than b and less than c, the phase difference determination unit 91 sets the phase difference to λ / 16.

[0261] In step S30, if it is determined in step S26 that the contrast ratio CR is greater than or equal to c and less than d, the phase difference determination unit 91 sets the phase difference to λ / 8.

[0262] In step S31, if it is determined in step S26 that the contrast ratio CR is d or higher, the phase difference determination unit 91 sets the phase difference to λ / 4.

[0263] The phase difference determination unit 91 controls the liquid crystal devices 1R, 1G, and 1B respectively to make the phase difference of the first phase difference control element 60 the same as the phase difference of the second phase difference control element 70. Furthermore, the phase difference can also be corrected based on individual differences between the first phase difference control element 60 and the second phase difference control element 70.

[0264] In step S22, the phase difference control signal output unit 92 outputs phase difference control signals RcR, RcG, and RcB to the first phase difference control elements 60R, 60G, 60B and the second phase difference control elements 70R, 70G, 70B of the liquid crystal devices 1R, 1G, 1B, based on the phase difference determined by the phase difference determination unit 91.

[0265] The liquid crystal device 1R, based on the phase difference control signal RcR, applies the voltage driving the liquid crystal layer 67 of the first phase difference control element 60R and the liquid crystal layer 77 of the second phase difference control element 70R to the electrodes 63 and 64 of the first phase difference control element 60R and the electrodes 73 and 74 of the second phase difference control element 70R. This controls the phase differences of the first phase difference control element 60R and the second phase difference control element 70R.

[0266] Similarly, the liquid crystal device 1G controls the phase differences of the first phase difference control element 60G and the second phase difference control element 70G based on the phase difference control signal RcG. The liquid crystal device 1B controls the phase differences of the first phase difference control element 60B and the second phase difference control element 70B based on the phase difference control signal RcB.

[0267] In step S27, when the phase difference is zero, the first phase difference control elements 60R, 60G, 60B and the second phase difference control elements 70R, 70G, 70B become the linear polarization mode as the first mode, and their phase difference is controlled so that the polarization state of the incident linear polarized light is maintained and emitted without changing the polarization state of the incident linear polarized light.

[0268] exist Figure 13B In low-contrast scenarios, select Mode 1, which prioritizes contrast. In low-contrast situations, the lateral electric field between pixels is less likely to increase, suppressing the formation of reverse deflection areas. Even if reverse deflection areas do occur, it's difficult for viewers to visually confirm the negative impact of the orientation. Therefore, by setting contrast priority as Mode 1, the display quality seen by viewers can be improved.

[0269] In steps S28 to S31, the second mode is entered. The first phase difference control element 60 converts the incident linearly polarized light into elliptically polarized light or circularly polarized light according to the phase difference and emits it. The second phase difference control element 70 converts the incident elliptically polarized light or circularly polarized light into linearly polarized light according to the phase difference and emits it. In addition, when the phase difference is λ / 32, λ / 16, or λ / 8, the second phase difference control element 70 converts the incident elliptically polarized light into linearly polarized light and emits it. When the phase difference is λ / 4, it converts the incident circularly polarized light into linearly polarized light and emits it. When the phase difference is zero, the incident linearly polarized light is emitted as linearly polarized light.

[0270] exist Figure 14B In such a high-contrast scene, the lateral electric field between pixels increases, which can easily create reverse deflection areas. In addition, the effect of misalignment is also easily visually confirmed. Therefore, by setting it as the second mode to prioritize improving misalignment, the display quality seen by the viewer can be improved.

Claims

1. A liquid crystal device comprising: A liquid crystal panel having a first liquid crystal layer; The first polarizing element is disposed on the light incident side of the liquid crystal panel; The second polarizing element is disposed on the light-emitting side of the liquid crystal panel; The first phase difference adjustment element is disposed between the first polarizing element and the liquid crystal panel and has a second liquid crystal layer; A second phase difference adjustment element, disposed between the liquid crystal panel and the second polarizing element, having a third liquid crystal layer; and The control unit controls the voltage applied to the second liquid crystal layer and the third liquid crystal layer. The first phase difference adjustment element has a first incident-side alignment film and a first emission-side alignment film sandwiched between the second liquid crystal layer. The first incident-side alignment film and the first emission-side alignment film are inorganic alignment films that align the liquid crystal molecules of the second liquid crystal layer in a first direction. The second phase difference adjustment element has a second incident-side alignment film and a second emission-side alignment film sandwiched between the third liquid crystal layer. The second incident-side alignment film and the second emission-side alignment film are inorganic alignment films that align the liquid crystal molecules of the third liquid crystal layer in a second direction that intersects the first direction. The control unit controls the phase difference imparted by the second liquid crystal layer to the incident light and the phase difference imparted by the third liquid crystal layer to the incident light according to the image displayed on the liquid crystal panel.

2. The liquid crystal device according to claim 1, wherein, The light-transmitting area of ​​the first phase difference adjustment element includes a first light-transmitting area and a second light-transmitting area. The voltage value applied to the second liquid crystal layer in the first light-transmitting area is different from the voltage value applied to the second liquid crystal layer in the second light-transmitting area. The light-transmitting area of ​​the second phase difference adjustment element includes a third light-transmitting area and a fourth light-transmitting area. The voltage value applied to the third liquid crystal layer in the third light-transmitting area is different from the voltage value applied to the third liquid crystal layer in the fourth light-transmitting area.

3. The liquid crystal device according to claim 1 or 2, wherein, The thickness of the second liquid crystal layer is less than or equal to the thickness of the first liquid crystal layer. The thickness of the third liquid crystal layer is less than or equal to the thickness of the first liquid crystal layer.

4. The liquid crystal device according to claim 1 or 2, wherein, The birefringence Δn2 of the liquid crystal material contained in the second liquid crystal layer is less than or equal to the birefringence Δn1 of the liquid crystal material contained in the first liquid crystal layer. The birefringence Δn3 of the liquid crystal material contained in the third liquid crystal layer is less than or equal to the birefringence Δn1 of the liquid crystal material contained in the first liquid crystal layer.

5. The liquid crystal device according to claim 1 or 2, wherein, The control unit controls the voltage applied to the second liquid crystal layer, such that the phase difference imparted by the second liquid crystal layer to the incident light is smaller than the phase difference imparted by the third liquid crystal layer to the incident light.

6. The liquid crystal device according to claim 1 or 2, wherein, The control unit controls the voltage applied to the second liquid crystal layer, such that the phase difference imparted by the second liquid crystal layer to the incident light is greater than the phase difference imparted by the third liquid crystal layer to the incident light.

7. The liquid crystal device according to claim 1 or 2, wherein, The control unit controls the voltage applied to the second liquid crystal layer and the third liquid crystal layer such that the sum of the following phase differences is the same as the phase difference imparted by the third liquid crystal layer to the incident light. The sum of the phase differences is the sum of the phase difference imparted by the second liquid crystal layer to the incident light and the phase difference imparted by the first liquid crystal layer to the incident light when the display is black.

8. The liquid crystal device according to claim 1 or 2, wherein, The control unit controls the voltage applied to the second liquid crystal layer and the third liquid crystal layer, such that the phase difference imparted by the second liquid crystal layer to the incident light is the same as the sum of the following phase differences, which is the sum of the phase difference imparted by the first liquid crystal layer to the incident light and the phase difference imparted by the third liquid crystal layer to the incident light when the display is black.

9. The liquid crystal device according to claim 1 or 2, wherein, The control unit controls the phase difference imparted by the second liquid crystal layer to the incident light and the phase difference imparted by the third liquid crystal layer to the incident light within the range of 0 ≤ Δnd ≤ λ / 4. Δnd is the delay of the first liquid crystal layer.

10. A display device comprising a liquid crystal device according to any one of claims 1 to 9.

11. A display device comprising: A first liquid crystal panel that modulates light of a first wavelength; and The second liquid crystal panel modulates light of a second wavelength, which has a wavelength different from the first wavelength. The display device has: The first phase difference adjustment element is disposed on the light incident side of the first liquid crystal panel and has a second liquid crystal layer; A second phase difference adjustment element, disposed on the light-emitting side of the first liquid crystal panel, has a third liquid crystal layer; and The control unit controls the voltage applied to the second liquid crystal layer and the third liquid crystal layer. The display device includes: a third phase difference adjustment element disposed on the light incident side of the second liquid crystal panel and having a fourth liquid crystal layer; and a fourth phase difference adjustment element disposed on the light emitting side of the second liquid crystal panel and having a fifth liquid crystal layer. The control unit controls the voltage applied to the second liquid crystal layer and the third liquid crystal layer, such that the phase difference imparted by the second liquid crystal layer to the incident light and the phase difference imparted by the third liquid crystal layer to the incident light become the first phase difference, respectively. The control unit controls the voltage applied to the fourth liquid crystal layer and the fifth liquid crystal layer, such that the phase difference imparted by the fourth liquid crystal layer to the incident light and the phase difference imparted by the fifth liquid crystal layer to the incident light become the second phase difference, which is different from the first phase difference.

12. The display device according to claim 11, wherein, When the liquid crystal driving voltage at the maximum brightness of the first liquid crystal panel is higher than the liquid crystal driving voltage at the maximum brightness of the second liquid crystal panel, The control unit performs control such that the first phase difference is greater than the second phase difference.

13. The display device according to claim 11, wherein, The thickness of the liquid crystal layer of the first liquid crystal panel is thinner than the thickness of the liquid crystal layer of the second liquid crystal panel.

14. The display device according to claim 11, wherein, The birefringence Δn of the liquid crystal layer of the second liquid crystal panel is less than the birefringence Δn of the liquid crystal layer of the first liquid crystal panel.

15. The display device according to claim 11, wherein, When the birefringence Δn of the liquid crystal layer of the second liquid crystal panel is less than the birefringence Δn of the liquid crystal layer of the first liquid crystal panel, The control unit makes the second phase difference greater than the first phase difference.

16. An optical modulation module, comprising: A liquid crystal panel having a first liquid crystal layer; The first polarizing element is disposed on the light incident side of the liquid crystal panel; The second polarizing element is disposed on the light-emitting side of the liquid crystal panel; The first phase difference adjustment element is disposed between the first polarizing element and the liquid crystal panel and has a second liquid crystal layer; The second phase difference adjustment element is disposed between the liquid crystal panel and the second polarizing element, and has a third liquid crystal layer. The light modulation module controls the voltage applied to the second liquid crystal layer and the third liquid crystal layer. The first phase difference adjustment element has a first incident-side alignment film and a first emission-side alignment film sandwiched between the second liquid crystal layer. The first incident-side alignment film and the first emission-side alignment film are inorganic alignment films that align the liquid crystal molecules of the second liquid crystal layer in a first direction. The second phase difference adjustment element has a second incident-side alignment film and a second emission-side alignment film sandwiched between the third liquid crystal layer. The second incident-side alignment film and the second emission-side alignment film are inorganic alignment films that align the liquid crystal molecules of the third liquid crystal layer in a second direction that intersects the first direction. The light modulation module controls the phase difference imparted by the second liquid crystal layer to the incident light and the phase difference imparted by the third liquid crystal layer to the incident light according to the image displayed on the liquid crystal panel.

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