JP4602369B2 - Stereoscopic image display device - Google Patents

Description

  The present invention relates to a stereoscopic image display device.

Proposed as a stereoscopic image display method using a two-dimensional flat display device that combines and displays images from multiple gaze directions on the image display surface and selectively recognizes corresponding images according to the viewpoint position of the observer Has been.

As a stereoscopic image display method, the display image is a two-lens type by setting two images to be observed at the viewpoint positions of the left and right eyes. There is an expression. In addition, there is an integral photography method (IP method) in which images are synthesized and displayed on an image display surface for a number of viewing directions without being conscious of the viewpoint position.

As a means for selecting an image, a method of providing a pair of optical shields and openings in the form of a pinhole or slit in an array form, a lens array or a lenticular lens array on the image display surface, and the lens imaging position There is known a method of setting a pixel position. From the viewpoint of display luminance, it is desirable that the image selection means use a lens because the display luminance is lowered due to the presence of the shielding portion.

Various methods for selectively displaying a two-dimensional image and a three-dimensional image have been proposed in order to meet the demand for selectively displaying a two-dimensional image and a three-dimensional image using the same display device. In a configuration in which a lens array is used as an image selection means, a selection display method for switching the presence or absence of a lens action by using a lens as a refractive index variable layer has been proposed (for example, Patent Document 1).
. Here, it is described that a liquid crystal lens for controlling the orientation of the liquid crystal is used for the refractive index control realizing means. When displaying a two-dimensional image by switching the presence or absence of lens action,
It is possible to display an image with the original resolution of the three-dimensional flat display device.

As a method for realizing a liquid crystal lens, a liquid crystal material is sealed between a convex or concave lens surface and a substrate (Non-Patent Document 1), and the lens structure is a Fresnel lens structure (Non-Patent Document 2).
), A diffractive lens that gives refractive index modulation to the incident surface (Non-patent Document 3), and a refractive index distribution lens that gives refractive index modulation to the incident surface and the light propagation direction (Non-Patent Document 4). Etc. have been proposed.
JP 2000-102038 A S. Sato, J .; J. et al. App. Phys. Vol. 18, NO. 9, (1979) p. 1679-1684. S. Sato et al. , J. et al. J. et al. App. Phys. Vol. 24, NO. 8, (1985) p. L626-L628. S. T. T. Kowel et al. , App. Optics Vol. 23, NO. 2, (1984) p. 278-289. T. T. Nose et al. , Liquid Crystals Vol. 5, NO. 5, (1989) p. 145-1433.

Since a liquid crystal lens has birefringence (refractive index anisotropy), a lens effect is produced only for a specific polarization component. For this reason, it is practically difficult to design the focal length at a predetermined position and design the lens effect with or without considering the polarization direction, because there are many design restrictions, and only in limited liquid crystal operation modes. It was feasible.

On the other hand, the LCD (Liquid Crystal Display,
In the case of using a liquid crystal display), the LCD generally has a viewing angle dependency, and thus there is a restriction on the polarization direction of the display image. Therefore, if the polarization direction of the liquid crystal lens and the polarization direction on the image display means side are made to correspond directly, the design of the liquid crystal lens becomes difficult, and if it does not correspond, the crosstalk occurs in the display image due to the mixture of the lens action, The display quality was lowered.

Further, since the refractive index anisotropy of the liquid crystal is at most about 0.2, an attempt to control the presence or absence of the lens effect by controlling the alignment of the liquid crystal inevitably increases the thickness of the liquid crystal layer, resulting in about a subsecond. Only a slow response time could be realized.

Therefore, an undesired image may be displayed during a transient response period when switching between a two-dimensional image and a stereoscopic image.
Furthermore, when the liquid crystal lens is divided into a plurality of regions and a two-dimensional image and a stereoscopic image are to be displayed together, the voltage-alignment characteristic of the liquid crystal lens is gradual, so that passive matrix drive by line selection is difficult. There is a need for segment-type driving in which only a limited area can be selected or expensive active matrix driving.

An embodiment of the present invention includes an image display unit that arranges a plurality of pixels and emits polarized image light, and is provided on the image display unit and functions as a lens on light having a first polarization direction. A lens array that does not act on light having a second polarization direction different from the one polarization direction, and a birefringent phase modulation that is provided between the image display means and the lens array and rotates the polarization plane of the image light A stereoscopic image display device.

Here, the phase axis of the birefringent phase modulation means may be variable depending on the applied voltage.
The birefringent phase modulation means may change the phase axis for a partial screen of the image display means.
The birefringent phase modulation means may be capable of forming a plurality of regions having different phase axes on the screen of the image display means.
The lens array may include a liquid crystal layer and a pair of electrodes sandwiching the liquid crystal layer, and the focal position may be changed by a voltage applied between the electrodes.

As described above, according to the embodiment of the present invention, a two-dimensional image and a three-dimensional image can be switched and displayed, and the display quality is higher than that of the prior art. A stereoscopic image display device capable of displaying a mixed display of stereoscopic images in an arbitrary selection area can be provided.

Hereinafter, the stereoscopic image display device according to the present invention will be described in detail. However, the configuration of the present invention is not limited to the embodiments described below, and it is needless to say that the various configurations of the components described in the embodiments and examples of the invention can be combined. . For simplification of explanation, the same number is assigned to the same member over a plurality of drawings. In the figure, the z axis is taken from the display device toward the observer, the horizontal (left and right) direction in the display surface is taken as the x axis, and the vertical (up and down) direction is taken as the y axis.

Hereinafter, a first embodiment of the present invention will be described.
FIG. 1 is a diagram for explaining the outline of the present embodiment.
The stereoscopic image display apparatus according to the present embodiment includes an LCD 1 as an image display unit, and a birefringent lens array 6 having a lenticular lens function with a lens pitch substantially equal to an integer multiple of the pixels of the LCD 1. Further, a ½ wavelength film 5 is provided as a passive birefringence phase modulation means. Here, the light from the image display means toward the lens array is referred to as image light.
Some image display means emit light spontaneously and others use transmitted light from the back.
The light emitted from the image display means is collectively referred to as image light.

The LCD 1 has a structure in which a liquid crystal cell 3 having a liquid crystal sandwiched between transparent substrates is sandwiched between polarizing plates 2 and 4, and a stereoscopic image or a two-dimensional image is switched and displayed as a display image.

A back light source (not shown) is provided on the back surface of the polarizing plate 2, and the display image is composed of image light from linearly polarized light 9 having a polarization component in the direction of the polarization transmission axis 8 of the light exit side polarizing plate 4. .

The liquid crystal operation mode of the LCD 1 is a TN (Twisted Nematic) mode,
In order to keep the viewing angle characteristic in the left-right direction (in the xz plane) symmetrical, the direction of the polarization transmission axis 8 is θ = 45 °.

The half-wave film 5 is a light-transmitting film made of a heat-resistant transparent resin (for example, norbornene, polycarbonate optical resin) having birefringence, and has a phase axis direction 10 defined by a fast axis or a slow axis. Θ = 22.5 °. This half-wave film 5 rotates the incident linearly polarized light 9 to the outgoing polarized light 11 having the polarization direction θ = 0 ° while maintaining the linearly polarized light by 45 °.

The birefringent lens array 6 is a liquid crystal lens array using a liquid crystal cell in which liquid crystals having positive dielectric anisotropy are homogeneously aligned between parallel transparent substrates. That is, the voltage application means 7 applies a voltage to the comb-like electrodes provided in the liquid crystal cell, thereby generating a spatial distribution in the alignment state of the liquid crystal and providing a lens action. Here, the alignment direction of the liquid crystal is such that the molecular long axis (director) direction is θ = 0 °, and the electrode shape of the comb-like electrode is long in the y-axis direction and provided at a predetermined pitch in the x-axis direction. Yes. Therefore, the electric field distribution is symmetric with respect to the yz plane between the electrodes, and the liquid crystal molecular axis has a spatial distribution with respect to the xz plane while θ = 0 °.

As a result, a lenticular lens action occurs when a voltage is applied with respect to the incident polarization direction 12 of θ = 0 °. That is, the incident polarization direction 12 has a ridge line in the y-axis direction, and x
A lens action equivalent to the case where a lenticular lens array having a predetermined pitch in the axial direction is provided occurs. In the case of no voltage application, the spatial distribution of liquid crystal alignment disappears, and the lens action disappears.

On the other hand, for the incident polarization direction 13 of θ = 90 °, the refractive index is an ordinary ray refractive index regardless of the alignment state of the liquid crystal, and no lens action occurs.
With reference to FIG. 2, the structure and light condensing function of the lens array 6 using liquid crystal in the present embodiment will be described in more detail.
A common transparent electrode 16 and a comb-like electrode 17 are provided on a transparent parallel plate transparent substrate 61, respectively. A TN liquid crystal 15 is sandwiched between the transparent substrates 18.
Here, the voltage application method includes a case where the electrodes 16 and 17 are used as two terminals and an AC voltage is applied, and a case where the comb-like electrode 17 is used as a set for each even line and odd line and an AC voltage is applied as three terminals. There is.

In any case, applying a voltage between the electrodes 16 and 17 causes a spatial distribution of the electric field, and a lens function having a pitch p and a focal length f is generated for a polarization component having the polarization direction 12. Therefore, the locus of the linearly polarized light having the polarization direction 12 is bent in the lens array 6.

As described above, the alignment state of the liquid crystal layer 15 changes only in the direction of the molecular long axis with respect to the xz plane. Does not have. Accordingly, the polarization component 13 goes straight in the lens array 6.

In practice, a dielectric layer, an alignment film, and the like for appropriately controlling the electric field distribution are provided between the electrode and the liquid crystal interface, but are not shown in FIG.
Therefore, as shown in FIG. 3, by arranging such a lens array 6 so that the pixel 19 of the LCD 1 is located at the focal length f, for linearly polarized light having a polarization component in the x-axis direction, lenticular is used. It can be seen that a lens-type stereoscopic image display device can be configured.

As described above, in FIG. 1, the linearly polarized light 11 as image light can be made to coincide with the polarization direction 12 in which the switching of the lens action occurs in the lens array 6 by the polarization rotation action of the ½ wavelength film. .

The outgoing linearly polarized light 14 of the lens array 6 has a polarization direction of θ = 0 ° and is transmitted without being condensed or modulated by voltage application / non-application control of the voltage application means 7. Therefore,
By switching between voltage application / non-application of the voltage application means 7 in synchronization with the selection state of the stereoscopic image and the two-dimensional image, the display on the LCD 1 can be switched between a stereoscopic image having the maximum resolution and a two-dimensional image. Become.

When the half-wave film 5 is not used, the polarization direction of the image incident on the lens array 6 is θ
= Linearly polarized light 9 forming 45 °. Therefore, since the polarization component 13 that does not cause a lens action in the lens array 6 is included in the incident polarization component, crosstalk occurs in which images are displayed in a multiplexed manner during stereoscopic image display.

On the other hand, setting the outgoing polarization direction 8 in the LCD 1 to θ = 0 ° is not preferable in view angle characteristics of the LCD 1.
By tilting the lens array 6 and setting the polarization direction in which the lens action occurs to θ = 45 °, parallax information is generated in an oblique direction, and a stereoscopic image cannot be displayed.
Thus, the half-wave film 5 which is a passive birefringence phase modulation means optimizes the display characteristics of the LCD 1 and is excellent in that there is no crosstalk between a stereoscopic image using the lens array 6 and a two-dimensional image. It has a function that enables selection display.

Here, an example in which the LCD 1 that is an image display unit using polarized light is used as the image display unit has been described. However, an image display unit that does not use polarized light, such as a CRT (Cathode Ray), has been described.
Tube, CRT), PDP (Plasma Display Panel, Plasma Display), OLED (Organic Light Emission D)
iode, organic EL (Electro Luminescence)), FED (F
A polarizing plate may be provided on a display surface such as a field emission display (i.e., field emission display) to add polarization to a display image.

For the lens array 6, it is also possible to use an optical crystal having birefringence, such as calcite or quartz, processed into a lens shape. That is, the refractive index is not necessarily variable, and a passive element whose optical characteristics do not change dynamically may be used. Therefore, a liquid crystal lens array having a birefringence as a passive element can be realized by solidifying a liquid crystalline medium, for example, mixing a liquid crystal with a polymer liquid crystal or a monomer and polymerizing the liquid crystal with ultraviolet rays or heat in a predetermined alignment state. Can do.

In order to provide the lens array 6 with a liquid crystal lens and to give a lens action only in a specific incident polarization direction, a structure in which a liquid crystal material is sealed between parallel plates and the alignment state of the liquid crystal is spatially controlled by voltage application. desirable. Specifically, a diffractive lens that gives a refractive index distribution in the incident surface at a predetermined pitch, a refractive index distribution lens that gives a refractive index distribution in the light propagation direction, or a refractive index distribution in both the incident surface and the light propagation direction. It can be realized by giving.

In order to give a lenticular lens action to a specific polarization direction, for example, a homogeneous alignment cell using a nematic liquid crystal having positive dielectric anisotropy is used, and comb-shaped electrodes are arranged at a predetermined pitch with respect to the alignment direction of the liquid crystal. And provided in the vertical direction. As a result, a lenticular lens action can be generated on the specific polarization incident axis when a voltage is applied, and a lens having no lens action on the other polarization incident axes can be configured.

Here, the lenticular lens action means that a condensing action equivalent to the case where the ridge line direction of the lenticular lens (the direction in which the lens curvature is infinite) is aligned with the comb electrode direction is generated. In the liquid crystal lens having such a structure, the focal point can be made variable by changing the applied voltage. By applying no voltage, the lens action can be eliminated, that is, the ON / OFF control of the lens action can be performed by the ON / OFF control of the applied voltage.

FIG. 4 is a control block diagram for performing switching control between two-dimensional image display and three-dimensional image display in the present embodiment. Two-dimensional image display / stereoscopic image display switching selection input means 62 is a switch such as a keyboard and a mouse for switching selection between two-dimensional image display and three-dimensional image display by the observer.
Is transmitted to the stereoscopic image display control means 61. The stereoscopic image display control means 61 is an LCD
1, a graphic controller 63 having a display controller 65 for controlling image display of the LCD 1, a CPU 66, and a birefringent lens array for controlling the voltage applying means 7 of the birefringent lens array 6. The controller 67 is configured.

When the image display mode selection signal from the observer is received and the selected image display mode is stereoscopic image display, the CPU 66 stores the stereoscopic image data in the image data 64 and turns on the applied voltage to the birefringent lens array controller 67. The control signal is transmitted. The birefringent lens array controller 67 sets or controls the applied voltage value, applied voltage waveform, and frequency parameters for the voltage applying means 7. On the other hand, stereoscopic image data is displayed on the LCD 1 via the graphic controller 63, and the observer observes the stereoscopic image data through the birefringent lens array 6 to which a voltage is applied by the voltage applying means 7 and produces a lens effect. An image can be observed.

Similarly, when the two-dimensional image display is selected, the CPU 66 displays the two-dimensional image data on the LCD 1 via the graphic controller 63, and the birefringent lens array controller 67.
By transmitting a control signal of applied voltage OFF to the observer, the observer can observe the same two-dimensional image data as that of a normal LCD through the birefringent lens array 6 having no lens effect.

For a birefringent phase modulation means, in the case of a passive element having a fixed rotation angle in the polarization direction, a birefringent phase difference film using a transparent stretched film or a birefringent optical crystal such as calcite or quartz should be used. Can do.

The birefringent phase modulation means is a so-called 1/2 wavelength film (1/2 wavelength plate) in which the retardation has a value of 1/2 with respect to the incident wavelength in order to rotate the polarization plane. Single 1/2
When a wavelength film is used, the phase axis is arranged at an angle that equally divides the rotation angle of the polarization plane into ½, but in order to reduce the wavelength dispersion and increase the bandwidth, the ½ wavelength film or ½ In some cases, the polarization rotation operation is performed using a plurality of retardation films near the wavelength condition. For example,
A method of arranging two half-wave films in an orientation of 67.5 ° and 22.5 ° from the light incident side is known and applicable to the polarization rotation operation from 0 ° to 90 °. It is.

In order to make the phase axis rotation of the birefringent phase modulating means variable, it is preferable to use a liquid crystal cell for the birefringent phase modulating means.
For the phase axis variable control, a method of largely changing the phase axis angle and a method of selecting the presence or absence of the phase axis can be applied.
An example of a method for changing the phase axis angle is a ferroelectric liquid crystal (FLC, Fer
SSFLC (Su) using a low-electric liquid crystal material
rface Stabilized Ferroelectric Liquid Cr
ystal) or antiferroelectric liquid crystal (AFLC, Anti-Ferroselect)
Half-V (TLAF, Th) using ric Liquid Crystal material
operation mode such as “hold-less Anti-Ferroelectric mode” may be applied. These two operation modes are preferable from the viewpoint of quick response.

As an example of a method for selecting the presence or absence of a phase axis, a π twist cell (bend alignment cell) using a nematic liquid crystal material can be used as an operation mode that can similarly achieve a high response speed.

Further, in the case where the phase axis variable control of the birefringent phase modulation means is a partially selectable matrix type, a thin film transistor (TFT, Thin Film Transistor) is used.
It is desirable to use a liquid crystal operation mode that does not require a switching element such as) and can be driven by a passive matrix type, that is, selective scanning of line electrodes. As such a mode, an STN (Super Twisted Nematic) using a nematic liquid crystal material is used.
c) and BTN (Bi-stable Twisted Nematic) modes are applicable.

FIG. 5 is a schematic diagram for explaining the second embodiment.
Similarly to the previous embodiment, the LCD 1 and the lens array 6 having a lenticular lens function with a lens pitch substantially equal to an integer multiple of the pixels of the LCD 1 are provided as image display means. Detailed description of the same parts as in the previous embodiment will be omitted.

In the present embodiment, a ferroelectric liquid crystal cell 20 having spontaneous polarization is used as the birefringence phase modulation means. Thereby, it becomes an active element which can switch a phase-axis direction according to the display switching of a stereo image and a two-dimensional image.

The ferroelectric liquid crystal cell 20 has a ferroelectric liquid crystal sealed between a pair of substrates. Also,
An electrode is provided on each substrate, and a voltage can be applied to the ferroelectric liquid crystal. The ferroelectric liquid crystal cell 20 has spontaneous polarization, and becomes a half-wave plate by appropriately designing the liquid crystal material and the cell gap.

FIG. 6 is a side view of the configuration in the present embodiment. The ferroelectric liquid crystal cell 20 includes a transparent substrate 3.
7, a ferroelectric liquid crystal 39 is sandwiched through a common transparent electrode 38, and the common transparent electrode 38.
The orientation is changed by applying a voltage to the ferroelectric liquid crystal by the voltage applying means 21 connected to, and the phase axis direction is switched.

Similar to the first embodiment, the birefringent lens has a focal length f of the pixel 19 through the ferroelectric liquid crystal cell 20.
Set above. The substrate 3 on the side facing the ferroelectric liquid crystal cell 20 can be shared with the substrate 38 of the ferroelectric liquid crystal cell 20.

By switching the polarity of the applied voltage using the voltage applying means 21, the phase axis is set to the first phase axis azimuth θ = 22.5 ° (reference numeral 22 in the figure), and the second phase axis azimuth θ = 67.5 ° ( 23 in the figure)
The two states can be controlled.

Since the liquid crystal material has spontaneous polarization and the cell gap is thin, the ferroelectric liquid crystal cell 20 can respond faster than 1 ms compared to the slow response time of the liquid crystal lens. For this reason, when the phase axis is switched, it is possible to switch instantaneously by switching the polarity of the voltage applying means 21.

When the image light of the LCD 1 is linearly polarized light 9 forming θ = 45 °, when the ferroelectric liquid crystal cell 20 is controlled to the first phase axis azimuth 22, the direction of the output linearly polarized light 24 from the ferroelectric liquid crystal cell 20 is θ = 0 °. On the other hand, when the second phase axis direction 23 is controlled, the direction of the outgoing linearly polarized light 24 from the ferroelectric liquid crystal cell 20 is θ = 90 °.

Therefore, when the ferroelectric liquid crystal cell 20 is controlled to the first phase axis azimuth 22, the lens array 6
Functions as a lens and becomes a stereoscopic image display mode. On the other hand, when controlled to the second phase axis azimuth 23, the lens array 6 does not function as a lens and does not display a stereoscopic image. That is, the two-dimensional image display mode is set.

FIG. 7 is a control block diagram for performing switching control of 2D image / stereoscopic image display in the present embodiment. A two-dimensional image / stereoscopic image switching control means 69 for controlling voltage application to the ferroelectric liquid crystal cell 20 and the birefringent lens array 6 is composed of a ferroelectric liquid crystal cell controller 70 and a birefringent lens array controller 67. Thus, it is possible to perform voltage application control on the voltage application means independently of each other.

In the present embodiment, when liquid crystal is used for the lens array 6, the birefringent lens characteristics are maintained by applying a voltage to the lens array 6 steadily, and the stereoscopic image and the two-dimensional image of the image display means. The polarity of the voltage applying means 21 is selected in synchronization with the selection display of the image, and the lens array 6
Can be made to act as a lens or not. Therefore, it is possible to switch the display without making the observer visually recognize the undesired display characteristics that occurred during the transient response period of the liquid crystal lens.

In the case where a two-dimensional image is continuously displayed for a long period of time, the lens array 6 may be in a state in which no voltage is applied, as in the previous embodiment, from the viewpoint of reducing power consumption. Further, after the response of the liquid crystal lens is completed, even if the applied voltage to the ferroelectric liquid crystal cell 20 is not applied even if the ferroelectric liquid crystal cell 20 does not have a memory property, no inconvenience occurs.

FIG. 8 shows a 2D image display mode 40 for continuously displaying a 2D image for a long period of time. It is the table | surface which put together the state of the voltage application means at the time of the two-dimensional image display 42 in the image switching display mode 41, and the three-dimensional image display 43, and an output linearly polarized light.

In the two-dimensional image display mode 40, the applied voltage is not applied (OFF) in both the voltage applying unit 21 of the ferroelectric liquid crystal cell 20 and the voltage applying unit 7 of the birefringent lens array 6. Since the birefringent lens array 6 does not have a lens effect, the alignment state of the ferroelectric liquid crystal cell may be any state.

On the other hand, in the two-dimensional image / stereoscopic image switching display mode 41, since a voltage is applied via the voltage applying means 7 of the birefringent lens array 6, a lens effect is generated for linearly polarized light in the direction of θ = 0 °. The presence or absence of the lens effect is determined by selecting the direction of linearly polarized light incident on the birefringent lens array 6 according to the polarity of the voltage applied to the ferroelectric liquid crystal cell 20.

By the way, in the switching between the two-dimensional image display and the three-dimensional image display in the two-dimensional image / stereoscopic image display mode 41, since the response of the ferroelectric liquid crystal cell 20 is fast, an undesired display during the transient response period is not visually recognized. However, switching from the two-dimensional image display mode 40 to the two-dimensional image / stereoscopic image switching display mode 41 or switching in the reverse direction is accompanied by a change in the orientation of the birefringent lens array having a slow response, so that an undesired display is not visually recognized. Therefore, it is desirable to perform a mode switching operation by a predetermined sequence.

FIG. 9 is a diagram showing a voltage application sequence at the time of switching the image display mode.
The observer changes the 2D image display mode 40 to the 2D / stereo image switching display mode 41.
When the mode is selected, a positive polarity voltage + V applied at the time of two-dimensional image display is applied to the ferroelectric liquid crystal cell 20 from the voltage non-application (OFF) state via the voltage application means 21.
A voltage is applied to the birefringent lens array 6 via the voltage applying means 7 after a settling period 56 in which the response of the ferroelectric liquid crystal cell 20 is completely completed. In the birefringent lens array 6, the lens effect gradually appears with respect to the linearly polarized light in the θ = 0 ° direction during the transient response period 57, but the two-dimensional image display is selected in the ferroelectric liquid crystal cell 20. Therefore, the observation image does not change. After the response of the birefringent lens array 6 is completed, the two-dimensional image / stereoscopic image can be switched, and the display mode is selected according to the polarity of the voltage applied to the ferroelectric liquid crystal cell 20.

When the mode change from the two-dimensional image / stereoscopic image switching display mode 41 to the two-dimensional image display mode 40 is selected, the above reverse procedure, that is, first, the two-dimensional image / stereoscopic image switching display in the ferroelectric liquid crystal cell 20 is performed. Two-dimensional image display in mode 41 is performed, and then the voltage applied to the birefringent lens array 6 is shifted to the non-application state. After a transient response period 60 in which the lens effect of the birefringent lens array 6 completely disappears, the voltage applied to the ferroelectric liquid crystal cell 20 is set to the non-applied state. With this sequence, the observer can continue to observe the two-dimensional image without visually recognizing an undesired display.

Furthermore, it is also possible to use a lens array 6 that does not rely on liquid crystals, as in the previous embodiment.

FIG. 10 is a schematic diagram for explaining a third embodiment of the present invention. FIG. 13 is a plan view of the birefringence phase modulating means in the present embodiment.
The present embodiment is characterized in that the birefringence phase modulation means is a liquid crystal cell 25 capable of matrix driving.
Similarly to the previous embodiment, the LCD 1 and the lens array 6 having a lenticular lens function with a lens pitch substantially equal to an integer multiple of the pixels of the LCD 1 are provided as image display means. Detailed description of the same parts as in the previous embodiment will be omitted.

In this embodiment, for ease of explanation, the polarization direction 4 of the image light on the LCD 1 is set to θ = 0 °.
Will be described. Such a polarizing plate arrangement is VA (Vertically Align).
In the IPS (In-Plane Switching) mode, it is possible to apply without adversely affecting the viewing angle characteristics.

The liquid crystal cell 25 has a liquid crystal sealed between a pair of substrates, and electrodes for applying a voltage to the liquid crystal are provided on both substrates. The liquid crystal cell 25 has an electrode configuration capable of matrix driving. Here, the matrix driving is a driving method in which a voltage is applied to a desired region 30 by dividing the surface of the liquid crystal cell 25 into a plurality of regions 30 as shown in FIG. As an electrode structure for matrix driving, TFT driving used in a normal liquid crystal display device or passive matrix driving for applying a predetermined voltage pulse by making the comb electrodes orthogonal may be used.

As an example of the liquid crystal cell 25 that can be driven by a matrix, the structure of a liquid crystal cell in the case of using a passive matrix type STN mode liquid crystal cell is shown in FIG. Comb transparent electrode 8 on the opposite side
STN mode liquid crystal 81 is sandwiched between transparent substrates 80 on which 2 is formed. L can be applied to any region 30 by applying a voltage pulse to the comb-shaped transparent electrode 82.
A CD driver is provided as the voltage applying means 27.

FIG. 12 is a control block diagram for controlling the display mode of the present embodiment. The two-dimensional image / stereoscopic image switching control means 69 is provided with a graphic controller 71 for displaying and controlling a window at a desired position of the liquid crystal cell 25, and a part of the image data 64 of the graphic controller 63 on the LCD 1 side. The window display control can be performed on the liquid crystal cell 25 at the same display position and size corresponding to the stereoscopic image data stored in the screen.

In this embodiment, in the region 29 where a voltage is applied to the liquid crystal, the phase axis disappears, and the polarization direction of incident light is not changed, but transmitted as it is. In the region where no voltage is applied, the polarization direction of incident light is rotated. Of course, depending on the type and mode of the liquid crystal used, it is possible to rotate the polarization direction of the incident light in a region to which a voltage is applied, and not to rotate the polarization direction in other regions.

In the region 29 in the liquid crystal cell 25, light is transmitted without changing the polarization component, so that the image light is transmitted through the liquid crystal cell 25 with the linearly polarized light 9 (θ = 0 °). The linearly polarized light 28 emitted from the liquid crystal cell 25 has an orientation of θ = 0 ° and enters the lens array 6. Therefore, a lens action occurs in the lens array 6 for the region 29.

On the other hand, in the region where no voltage is applied, since the phase axis 26 is θ = 45 °, the outgoing polarization direction from the liquid crystal cell 25 is θ = 90 °, and no lens action occurs in the lens array 6.

As described above, the matrix-driven liquid crystal cell 25 that satisfies the ½ wavelength condition is provided between the display unit 1 and the lens array 6, and the voltage application unit 27 applies a voltage to the partial region 29 of the liquid crystal cell 25. By applying, a stereoscopic image and a two-dimensional image can be easily mixed and displayed on one screen. For example, in FIG. 13, it is possible to provide a voltage application region 29 as a window in a region where a two-dimensional image is displayed, and display a stereoscopic image in the window. Even when the window is moved with the mouse, the stereoscopic image can be displayed at an arbitrary position by moving the voltage application region 29 in synchronization with the operation.

FIG. 14 is a diagram showing an example of a window screen design when a stereoscopic image is partially displayed by window display. The area 29 is an area for displaying an image. When the stereoscopic image display is selected, the stereoscopic image is displayed in the area 29. A region 83 outside the region 29 is displayed in high definition by two-dimensional image display. A window control bar for operating the window and a control button 84 for selecting two-dimensional image display and three-dimensional image display in the region 29 are provided. It is arranged in the window control bar area together with control buttons generally provided for operating opening and closing of the window. Here, the horizontal display size W of the region 29 is preferably an integral multiple of the pitch p of the birefringent lens array 6, and the vertical display size H is desirably an integral multiple of the vertical size of the unit region 30 of the liquid crystal cell 25. When an operation such as enlargement is performed, clipping is performed to meet this condition.

FIG. 15 is an example of a desirable display sequence when changing the display position of a window during stereoscopic image display. When the observer clicks the window control bar and selects it, as a move preparation process, the stereoscopic image is hidden by displaying a predetermined pattern image, and then the display mode is switched to 2D image display. . Furthermore, after the display mode is switched, a process 85 for confirming whether there is 2D image data corresponding to the displayed stereoscopic image and displaying the 2D image may be performed. By performing the switching process to the two-dimensional image display before the movement, it is not necessary to update the three-dimensional image display in accordance with the change of the display position during the moving operation of the window, and the response is performed as in the STN mode. Even if a liquid crystal display mode that is not so early is used, an undesired display caused by a mismatch (response delay) between the stereoscopic image data and the window display position is not visually recognized. After the window moving operation by the observer is finished, the image is not displayed, and the stereoscopic image display is performed after the switching operation to the stereoscopic image display mode.

FIG. 16 is a diagram for explaining the fourth embodiment.
In the present embodiment, the half-wave film 5 is further added to the configuration in the first embodiment.
B and a liquid crystal lens 6B are added, and the birefringence phase modulation means and the lens array are configured in two stages to form a stereoscopic image display device to which vertical parallax is imparted.

Similarly to the previous embodiment, the LCD 1 is provided as an image display means, and a lens array 6A having a lenticular lens action with a lens pitch substantially equal to an integer multiple of the pixels of the LCD 1 is provided. Detailed description of the same parts as in the previous embodiment will be omitted. A birefringence phase modulation means 5A is provided between the LCD 1 and the lens array 6A.

The added lens array 6B has a structure obtained by rotating the lens array 6A by 90 °, and has a lenticular lens action in the vertical direction of the screen with respect to the polarization direction 12B of θ = 90 ° when a voltage is applied. The focal position of the lens is set so as to be located in the pixel portion of the LCD 1 like the lens array 6A.

The phase axis azimuth 10B of the added birefringence phase modulation means 5B is θ = 45 °, and the polarization direction θ = 0 ° of the light emitted from the lens array 6A is rotated by 90 ° to thereby obtain the lens array 6B.
To enter. Thereby, a lens action occurs in the lens array 6B in the light incident on the lens array 6B.

A side view of the configuration of this embodiment is shown in FIG. The focal lengths fA and fB of the birefringent lens array 6A that generates the vertical parallax and the birefringent lens array 6B that generates the horizontal parallax are set so that the focal point is located at the pixel 19 of the LCD 1 as in the previous embodiments. The Since the lens effect in both birefringent lens arrays is generated perpendicular to the horizontal and vertical directions of the screen, the focal length may be set independently regardless of the lens state of each other.

By adopting such a two-stage structure, not only the selective display of a stereoscopic image and a two-dimensional image, but also the lateral parallax and the vertical parallax at the time of stereoscopic image display are controlled by applying voltage independently to the respective liquid crystal lenses 6A and 6B. It becomes possible to add freely. In addition, by dividing the comb-like electrodes in each liquid crystal lens into several groups and performing independent control, it is possible to set a plurality of parallax numbers when displaying a stereoscopic image. For example, since a plurality of conditions such as 16 × 6 and 32 × 3 can be set for the number of horizontal parallaxes × the number of vertical parallaxes, it is possible to set a stereoscopic image display condition optimal for display content and observation conditions.

FIG. 18 shows a control block diagram in the present embodiment. The two-dimensional image / stereoscopic image switching control means 69 for controlling the birefringent lens arrays 6A and 6B is composed of birefringent lens array controllers 67A and 68B for controlling each lens array independently. In the image data 64 of the graphic controller 63, a two-dimensional image corresponding to the display mode and stereoscopic image data having a predetermined number of parallaxes are stored and displayed on the LCD 1.

The block diagram in connection with the 1st Embodiment of this invention. Sectional drawing explaining the structure and condensing effect of the liquid crystal lens in the 1st Embodiment of this invention. Sectional drawing which showed the imaging characteristic at the time of the three-dimensional image display by the liquid crystal lens in the 1st Embodiment of this invention. The control block diagram in the 1st Embodiment of this invention. The block diagram in connection with the 2nd Embodiment of this invention. The side view of the structure in connection with the 2nd Embodiment of this invention. The control block diagram in the 2nd Embodiment of this invention. The figure which showed the relationship between the display mode in the 2nd Embodiment of this invention, a voltage application state, and a polarization state. The figure which showed the switching sequence at the time of switching of the image display mode in the 2nd Embodiment of this invention. The block diagram in connection with the 3rd Embodiment of this invention. The figure which shows the structure of the passive matrix type liquid crystal cell in connection with the 3rd Embodiment of this invention. The control block diagram in the 3rd Embodiment of this invention. In the 3rd Embodiment of this invention, the front view which showed the relationship between the stereoscopic image display area and the drive state of a liquid crystal cell. The figure which showed an example of the window screen in the 3rd Embodiment of this invention. The figure which showed the processing flow at the time of moving the window display position in the 3rd Embodiment of this invention. The block diagram in connection with the 4th Embodiment of this invention. The side view of the structure in connection with the 4th Embodiment of this invention. The control block diagram in the 4th Embodiment of this invention.

Explanation of symbols

1 ... LCD
2, 4 ... Polarizing plates 3, 18, 37, 80 ... Transparent substrates 5, 5A, 5B ... Half-wave films 6, 6A, 6B ... Liquid crystal lenses 7, 7A, 7B, 21 , 27... Voltage applying means 8... Polarizing plate transmission axes 9, 11, 14, 24, 28... Linearly polarized light 10, 10A, 10B, 22, 23, 26. , 12B: Polarization direction causing lens action 13: Polarization direction not producing lens action 15, 39, 81 ... Liquid crystal layer 16, 17, 38, 82 ... Transparent electrodes 19, 19A, 19B ··· Pixels 20, 25 ··· Liquid crystal cell 29 ··· Three-dimensional image display region 30 ··· Switching unit region 83 ··· Two-dimensional image display region 31 ··· Lenticular lens 32 ··· Principal ray 33 ··· Lens transmitted light 61 ... Stereoscopic image display control means 62 · 2-dimensional images / three-dimensional image display switching selection input means 63,71 ... graphic controller 64 ... image data 65,73 ... display controller 66 ... CPU
67, 67A, 67B ... birefringent lens array controller 68 ... LCD driver 69 ... two-dimensional / stereoscopic image switching control means 70 ... ferroelectric liquid crystal cell controller 72 ... window data 84 ..Control button 85 ... 2D image display processing

Claims (14)

Image display means for arranging a plurality of pixels and emitting image light having polarization;
A lens array provided on the image display means, which acts on light having a first polarization direction and does not act on light having a second polarization direction different from the first polarization direction;
A birefringent phase modulation unit that is provided between the image display unit and the lens array, and rotates the polarization plane of the image light to match the outgoing light with the first polarization direction;
The birefringent phase modulation means has a phase axis that is variable depending on an applied voltage . 2. The stereoscopic image display apparatus according to claim 1, wherein the birefringent phase modulation means can apply the applied voltage to an arbitrary region corresponding to a partial screen of the image display means.
2. The stereoscopic image display device according to claim 1, wherein the birefringent phase modulation means can apply different applied voltages to a plurality of arbitrary regions on the screen of the image display means. .
The stereoscopic image display device according to claim 1, wherein the lens array includes a liquid crystal layer and a pair of electrodes sandwiching the liquid crystal layer, and a focal position is changed by an applied voltage between the electrodes.
The birefringent phase modulation means has a liquid crystal layer and a pair of electrodes sandwiching the liquid crystal layer, and controls the phase axis by switching the polarity of the voltage applied between the electrodes. The stereoscopic image display apparatus according to claim 1.
Depending on the choice of the three-dimensional image and a two-dimensional image, wherein by switching the polarity of the voltage applied to the birefringent phase modulating means, the stereoscopic image display and according to claim 5 which is characterized in that switching the two-dimensional image display 3D display device.
Image display means for arranging a plurality of pixels and emitting image light having polarization;
A liquid crystal layer provided on the image display means and a pair of first electrodes sandwiching the liquid crystal layer, and a lens action to light having a first polarization direction is controlled by an applied voltage between the electrodes. A lens array,
Provided between the image display means and the lens array, and having a liquid crystal layer and a pair of second electrodes sandwiching the liquid crystal layer, and rotating the polarization plane of the image light, Birefringent phase modulation means for matching with one polarization direction,
The stereoscopic image display device , wherein the birefringent phase modulation means controls the phase axis by switching the polarity of the voltage applied between the second electrodes .
The stereoscopic display device according to claim 7 , wherein one of the electrodes is a comb-like electrode.
8. The stereoscopic display device according to claim 7 , wherein the stereoscopic image display and the two-dimensional image display are switched by controlling the voltage applied to the lens array in accordance with the selection of the stereoscopic image and the two-dimensional image.
Depending on the choice of the three-dimensional image and the two-dimensional images, by switching the polarity of the applied voltage between the second electrode of the birefringent phase modulation means, the display of the display and the two-dimensional image of the stereoscopic image The stereoscopic display device according to claim 7 , wherein the stereoscopic display device is switched. The birefringent phase modulation means includes a liquid crystal layer and a pair of electrodes sandwiching the liquid crystal layer, and controls a phase axis by controlling a voltage applied between the electrodes. The stereoscopic image display device according to claim 1 or claim 7 .
Depending on the choice of the three-dimensional image and a two-dimensional image, wherein by controlling the voltage applied to the birefringent phase modulation means, according to claim 11 solid according which is characterized by switching the three-dimensional image display and two-dimensional image display Display device. The birefringent phase modulation means has a liquid crystal layer and a pair of electrodes that drive the matrix sandwiching the liquid crystal layer, and partially controls the phase axis by controlling the voltage applied between the electrodes. The three-dimensional image display apparatus according to claim 1 or 7, wherein
Depending on the choice of the three-dimensional image and a two-dimensional image, wherein by controlling the voltage applied to the birefringent phase modulation means, claim and characterized by switching the partial three-dimensional image display and two-dimensional image display 13 The three-dimensional display apparatus of description.

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