JP3297191B2 - Projection display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection display device capable of displaying a stereoscopic image utilizing polarized light.

[0002]

2. Description of the Related Art FIG. 10 is an explanatory view of a projection type display device capable of displaying a stereoscopic image according to a first conventional example. In the figure, 60R and 60L are right-eye projectors and left-eye projectors, 61 and 62 are polarizing plates, 10 is a screen, and 23 is polarizing glasses.

Next, the operation will be described. Each of the projectors 60R and 60L has a built-in image display device such as a CRT or a liquid crystal panel. For these image display devices, the right eye output from a signal source (not shown),
The parallax image for the left eye is displayed, and the projector 60R, 60
The parallax image is displayed on the screen 1 by the projection lens at the tip of L.
Enlarge and project on 0.

[0004] Polarizing plates 61 and 62 whose polarization axes are orthogonal to each other are arranged at the exit ends of the projection lenses of the projectors 60R and 60L, and the right-eye and left-eye projected images are projected as linearly polarized light orthogonal to each other. The viewing of the image is performed by wearing the polarizing glasses 23. That is, the right-eye projector 60 and the right-eye projector 60
R, polarizing plates 26R and 26L having polarization axes orthogonal to each other are provided to selectively transmit the linearly polarized light projected by the left-eye projector 60L, and the enlarged and projected parallax images are viewed by the right and left eyes, respectively. Can realize stereoscopic vision.

FIG. 11a shows, for example, "Imai et al .: Proceedings of the IEICE Spring National Convention (1989), C-84".
FIG. 2 is a configuration diagram of a projection display device capable of displaying a stereoscopic image according to a second conventional example described in FIG. In the figure, 1 is a light source, 50, 51, 52 are mirrors, 53, 55 are polarization beam splitters, 54L, 54R are color liquid crystal panels,
56 is a λ / 4 plate, 8 is a projection lens, and 9 is projection light.

Next, the operation will be described. A light beam emitted from the light source 1 is split into two linearly polarized light beams of polarization components (p-polarized light and s-polarized light) orthogonal to each other by a polarization beam splitter 53, and displays parallax images for the right and left eyes, respectively.
The liquid crystal panels 54R and 54L are illuminated. The s-polarized light and p-polarized transmitted light emitted from the liquid crystal panels 54R and 54L are combined by the polarization beam splitter 55, and the λ / 4 plate 56 converts the p-polarized light and s-polarized linearly polarized light clockwise and counterclockwise circularly polarized light, respectively. The light is converted into light and the liquid crystal panel 54R is
The 54L parallax image is converted into projection light 9 and enlarged and projected on a screen (not shown). As shown in FIG. 11B, the observer 24 returns the λ / 4 plate 25 that returns the circularly polarized light to the linearly polarized light.
R, 25L, polarizing plate 26 having polarization axes orthogonal to each other
Stereoscopic vision can be realized by wearing the circularly polarized glasses 23 to which R and 26L are attached and selectively observing the images for the right and left eyes with the corresponding eyes.

[0007]

In the projection type display apparatus of the first prior art shown in FIG. 10, two projectors 60L and 60R are required for projecting a parallax image, and a stereoscopic image can be observed without fatigue. In order to do so, it is necessary to make an adjustment for correctly overlaying the parallax images on the screen 10. Due to these factors, there has been a problem that the entire apparatus is expensive and large, and it takes time to install and adjust the apparatus.

Further, in the apparatus of the second conventional example shown in FIG. 11, a parallax image can be projected by one projector, so that the above-mentioned problem of the first conventional example is solved, but a color stereoscopic image is projected. For this purpose, it is necessary to use, for example, a color panel in which three primary color pixels of red, green, and blue are arranged as the liquid crystal panels 54R and 54L, and the number of pixels for each primary color is not sufficient to increase the definition of a projected image. There was a problem. In addition, when each primary color light is obtained by a color filter arranged on each pixel of the liquid crystal, in principle, 2/3 of the color filter is used.
The above luminous flux is lost, which has been a problem in achieving higher luminance.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a first object of the present invention is to provide a projection type display device capable of displaying a small and easily installable stereoscopic image. is there.

A second object of the present invention is to provide a projection display device which can secure a sufficient number of pixels and can display a stereoscopic image suitable for high luminance.

A third object of the present invention is to provide a projection type display device which has high reliability and can realize a stereoscopic image display with less flicker.

A fourth object of the present invention is to provide a projection display apparatus in which crosstalk between left and right parallax images is small.

A fifth object is to provide a small-sized projection display device which is easy to assemble.

[0014]

According to the present invention, there is provided a projection type display device which transmits light of different polarization states.
A first polarizing plate for the first eye and a second polarizing plate for the second eye;
Image viewed by an observer using polarized glasses
A light source and a plurality of rows and columns
Light beam emitted from the light source.
Converts to linearly polarized light and within the plane containing the plurality of pixels
And a light valve that modulates the light valve.
The first eye image is displayed on several lines, and the light
The first to display an image for the second eye on the even rows of the valve
Display mode and second eye on odd rows of the light valve
And display the image on the even-numbered line of the light valve.
The second display mode for displaying the first eye image is:
The light valve is switched so as to be switched every field cycle.
A light valve driving circuit for driving the light valve;
A plurality of row electrodes corresponding one-to-one to the row of
Change the polarization direction of incident light according to the voltage applied to the electrode
And the polarization state of the incident light is 90 degrees.
° The second state of rotating and passing can be set for each line
Polarization switching means, and an odd-numbered row of the polarization switching means.
In the first state, the even-numbered rows of the polarization switching means are provided.
A first transmission mode for bringing the second state into the second state;
Setting the odd numbered row of the switching means to the second state and
A second operation for setting the even rows of the polarization switching means to the first state;
The transmission mode is switched in synchronization with the field period.
Light switching means scanning circuit, emitted from the light source,
The light beam passing through the light valve and the polarization switching means
Projection lens means for enlarging and projecting .

Further, a plurality of light valves for displaying an image and polarization switching means are provided on each of the emission sides of the light valves, and the output light of each polarization switching means is combined and projected.

Also, a plurality of light valves for displaying images, polarization switching means on each of the light emitting sides of the light valves,
A λ / 4 plate for converting the output light of each polarization switching means into clockwise circularly polarized light and counterclockwise circularly polarized light according to the polarization switching state, and combining and projecting the output light of each polarization switching means. .

[0017]

The image display light valve comprises a cell in which a TN mode liquid crystal is sealed, and a first liquid crystal panel comprising a polarizing plate disposed on the illumination light incident side or on both sides of the illumination light incidence / emission side. The means comprises a second liquid crystal panel having a structure in which a ferroelectric liquid crystal is sandwiched between two transparent substrates. In the ferroelectric liquid crystal, the orientation direction of the liquid crystal molecules varies in the plane of the transparent substrate according to the polarity of the applied voltage. State 1 and State 2
In the state 1, the light emitted from the first liquid crystal panel is transmitted without rotating the polarization direction, and in the state 2, the polarization direction of the light emitted from the first liquid crystal panel is rotated by 90 °. It is transmitted through.

The light valve for displaying an image comprises a cell in which a TN mode liquid crystal is sealed, and a first liquid crystal panel comprising a polarizing plate disposed on the illumination light incident side or on both the illumination light incident / emission side. The switching means comprises a second liquid crystal panel having a structure in which a TN mode liquid crystal is sandwiched between two transparent substrates, and the TN mode liquid crystal of the second liquid crystal panel has two states, State 1 and State 2, according to the applied voltage. In the state 1, the light emitted from the first liquid crystal panel is transmitted without rotating the polarization direction. In the state 2, the light emitted from the first liquid crystal panel is rotated by 90 °. It is transparent.

[0020]

The projection lens is a telecentric lens system in which the off-axis principal ray on the light valve side is parallel to the optical axis of the projection lens. Both the light valve and the polarization switching means have an electrode structure that is periodic in the vertical direction. The pitch of the electrodes in the vertical direction of the light valve and the polarization switching means is made equal.

Further, the projection lens is a non-telecentric lens system, the light valve has a periodic electrode structure having a vertical pitch Pl, and the polarization switching means has a periodic electrode having a vertical pitch Pe. When the optical distance from the polarization switching means to the entrance pupil of the projection lens means is L2 and the optical distance from the light valve to the entrance pupil of the projection lens means is L1, the above Pl, P1 Satisfies the following relationship: Pl / Pe
= L1 / L2

Further, the light valve and the polarization switching means are integrally formed so that no space is formed between them.

[0024]

In the projection display device configured as described above, by switching the polarized light output from the light valve for each row, separate parallax images can be displayed for the right eye and the left eye. Thus, it is possible to realize a projection display device capable of displaying a stereoscopic image which is easy to install.

Further, since the output lights of the plurality of light valves are synthesized and projected, a high-definition and high-luminance stereoscopic image can be displayed.

The combined light of the plurality of light valves is represented by λ
Since the light can be converted into circularly polarized light that rotates in the opposite direction for the right and left eyes and projected by the / 4 plate, the crosstalk between the left and right parallax images can be reduced even if the observer tilts the head left and right.

Further, by applying a scanning signal to a row electrode having a periodic structure, the state of the polarization switching element is switched so as to alternately output images for the left eye and the right eye for each row, thereby providing a highly reliable apparatus. realizable.

Further, since the polarization of the display image of the TN mode liquid crystal can be controlled by the polarization switching element of the ferroelectric liquid crystal which operates at a high speed, a stereoscopic image with high contrast can be displayed.

Further, since the polarization of the display image of the TN mode liquid crystal can be controlled by the polarization switching element using the TN mode liquid crystal, a relatively inexpensive projection display device can be obtained.

Further, since an image for the right eye and an image for the left eye can be displayed in an interlaced manner by the action of the light valve driving circuit, the polarization switching element and the scanning circuit, a three-dimensional display with less flicker is possible.

Further, by combining a telecentric projection lens, a light valve having the same electrode period in the vertical direction, and a polarization switching element, crosstalk in stereoscopic display can be eliminated.

Further, the ratio of the distance from the entrance pupil position of the non-telecentric lens to the light valve and the polarization switching element is equal to the ratio of the vertical electrode period of the light valve and the vertical electrode period of the polarization switching element. By that
Crosstalk of stereoscopic display can be eliminated.

Further, since the light valve and the polarization switching element are integrally formed, the assembly of the projection type display device is facilitated, and a compact projection type display device with small left / right image crosstalk is obtained. Can be

[0034]

【Example】

<First Embodiment> FIG. 1 is a structural view showing an optical system of a projection display according to a first embodiment of the present invention. In the figure, 1
Is a light source, which comprises a lamp 11 for emitting white light and a reflecting mirror 12. 2R is a dichroic mirror that reflects red light and transmits green and blue light, 2G is a dichroic mirror that reflects green light and transmits blue light,
4 and 5 are reflection mirrors; 6R, 6G and 6B are liquid crystal panels (light valves) for displaying images in a plane;
G and 21B denote polarization switching elements, 8 denotes a projection lens, 10 denotes a screen, and 23 denotes polarizing glasses, provided with polarizing plates 26L and 26R having polarization axes orthogonal to each other for the left and right eyes.

Next, the operation will be described. The light source 1 reflects the luminous flux of a lamp 11 that emits white light, such as a metal halide lamp, a xenon lamp, and a halogen lamp, for example.
In step 2, the light is converted into a parallel illumination light beam. The illuminating light flux is decomposed into red, green and blue primary color lights by dichroic mirrors 2R and 2G made of a dielectric multilayer film, and illuminates the liquid crystal panels 6R, 6G and 6B via reflections at the reflection mirrors 3, 4 and 5.

Each of the liquid crystal panels 6R, 6G, and 6B has a configuration in which a TN (Twisted Nematic) mode liquid crystal cell is sandwiched between two polarizing plates, as described later. The liquid crystal cell has a matrix-shaped electrode on the inner surface in the vertical and horizontal directions. . The liquid crystal panel changes in-plane transmittance distribution in three primary color images corresponding to red, blue, and green according to an output signal of a driving circuit (not shown), and outputs linearly polarized image light. Polarization switching elements 21R, 21
G and 21B can control the polarization direction of the transmitted light of the liquid crystal panel for each row, as described later.
The transmitted light of each row of R, 6G and 6B is used for the right eye. The light is transmitted by alternately switching to the polarization direction for the left eye.

The transmitted light of the polarization switching element is synthesized by a dichroic prism 7 having a four-part configuration that reflects red and blue light and transmits green light, and is enlarged and projected as projection light 9 on a screen 10 by a projection lens 8. . The observer 24 views the projected image on the screen 10 through the polarizing glasses 23.

When the screen is of the transmission type, the observer views the screen on the side opposite to the projection lens 8 as shown, and when the screen is of the reflection type, the observer views the screen on the side of the projection lens 8. I do. The polarizing glasses 23 are provided with polarizing plates 26L and 26R having polarization axes orthogonal to each other at portions corresponding to the left eye and the right eye, and a stereoscopic effect can be obtained by viewing the corresponding parallax images with the left eye and the right eye.

FIG. 2 is a diagram showing the arrangement of the liquid crystal panel 6 and the polarization switching element 21 which are main parts of the configuration of FIG. The liquid crystal panel 6 includes an incident side polarizing plate 6P, an outgoing side polarizing plate 6A, and a liquid crystal cell 6L sandwiched therebetween. Liquid crystal cell 6
As for L, TN liquid crystal is injected between two transparent substrates as is known. On the inner surface of the transparent substrate, there are formed a matrix electrode 6M having a periodic structure in the up / down / left / right directions, an alignment layer for operating the liquid crystal in the TN mode, and the like. In order to display an image with high contrast, a thin film transistor (T) for holding image data is provided at the intersection of the matrix electrodes 6M.
FT) is formed. Also, the polarization axes of the polarizing plates 6P and 6A are typically orthogonal as shown by arrows,
Or they are in parallel.

The polarization switching element 21 includes a transparent substrate 21F,
A liquid crystal material is injected between the transparent substrates 21F and 21R.
On the inner surface of 21R, a transparent electrode and an alignment layer are formed.
At least one of the transparent electrodes is patterned so as to have a periodic structure in the Y direction (up-down direction), and is formed in a strip shape corresponding to the number of rows (sets of pixels in the X direction) of the matrix electrodes of the liquid crystal panel 6. Can be driven separately. The polarization switching element 21 is in a state where the transmitted light of the liquid crystal panel 6 is transmitted without changing the polarization direction according to the voltage applied to the strip-shaped electrode (state 1) and a state where the polarization direction is rotated by 90 degrees (state 2). Can be set for each line.

The left and right eye images are alternately displayed on the matrix electrodes 6M for each row in accordance with a signal applied from a liquid crystal panel drive circuit 30 described later. The strip-shaped electrode 21C is alternately switched between two states for the right eye and the left eye in accordance with a signal from the scanning circuit in synchronization with image writing for each row to the matrix electrode. In this way,
The incident light Li has a linear polarization direction of 9 for the left and right eyes for each row.
It is converted into image light Lo different by 0 °, and is enlarged and projected by a projection lens. In FIG. 1, since three sets of the liquid crystal panel 6 and the polarization switching element 21 are combined and projected, the display image has the number of pixels of each liquid crystal panel for each primary color, and the color liquid crystal is projected (see FIG. 11). ) Can be achieved with higher definition. Furthermore, a dichroic mirror 2 for color separation
If the bonding surface of the dichroic prism 7 for R, 2G, and color synthesis is made of a known dielectric multilayer film, the spectrum of illumination light emitted from the lamp can be separated and synthesized with low loss. Therefore, a color projection image with higher luminance can be obtained as compared with the color liquid crystal panel projection method (FIG. 11) that loses 2/3 of the illumination light spectrum in principle.

Next, as an example of the polarization switching element, an electro-optical λ / 2 plate (EO-HW: Electro Optical Hal) using a ferroelectric liquid crystal (FLC) is used.
f Wave Plate) will be described with reference to FIG. FIG. 5 is an operation explanatory view of the deflection switching element used in the present invention,
In the figure, the FLC cell 21 has a structure in which FLC is injected between two transparent substrates having a transparent electrode and an alignment layer on the inner surface. FLC is a uniaxial birefringent material whose optical axis is parallel to the average alignment direction of liquid crystal molecules. By appropriately setting the thickness of the FLC layer, the amount of phase shift can be set so as to function as a λ / 2 plate. Further, the orientation direction of the FLC molecules is switched to two directions parallel to the FLC layer at an angle of 45 ° to each other depending on the direction of the applied electric field. Therefore, the FLC alignment direction can be switched by applying a positive / negative voltage to the transparent electrode.

If the direction of the optical axis (Optical Axis) when the voltage -V is applied is adjusted to the polarization direction of the incident light as shown in FIG. 5A, the polarization direction of the transmitted light does not change. on the other hand,
When the voltage + V is applied as shown in FIG. 5B, the optical axis of the FLC is rotated by 45 ° in the panel plane, so that the polarization of the transmitted light is rotated by 90 ° as compared with FIG. 5A. In FIG. 5, EO-H
Although the transparent electrodes W are not divided, even if the transparent electrodes are divided into rows as shown by 21C in FIG. 2, the operation principle of the elements in each row is the same as that in FIG. In addition, since the response speed of the FLC can be as short as typically 100 μs or less, a stereoscopic image can be displayed with good contrast for the left and right eyes even when the polarization is switched for each row as shown in FIG.

The principle of polarization switching using the FLC as described above is described in, for example, (■ Background on Ferroelectri
c Liquid Crystals (FLCs) ■, DISPLAYTECH Inc.
(1991)).

In addition to the FLC, a liquid crystal retarder that controls the amount of phase shift due to birefringence of a nematic liquid crystal by an applied voltage is known. Such an element may be used as the EO-HW instead of the FLC. In this case, since the phase shift amount continuously changes with respect to the AC applied voltage, the phase shift amount is 0λ.
The state may be switched between the voltage of λ / 4 and the voltage of λ / 4. For more information on nematic liquid crystal retarders, see (PolarizationOptics Catalog & Handbook ■, p.
p.8-9, published by Meadowlark Optics, 1990). In addition, it is needless to say that an element whose electric phase shift amount can be electrically adjusted can be used for polarization switching in the apparatus of the present invention by performing row division driving. As described above, since the device of the present invention does not rely on a mechanical mechanism for switching polarization, the projection display device can be highly reliable.

Next, details of the drive circuit will be described with reference to the drawings. FIG. 3 is a configuration diagram of a driving circuit and a scanning circuit of the liquid crystal panel 6 and the polarization switching element 21 according to the present invention. In the drawing, 31L and 31R denote signal sources for the left and right eyes, respectively.
Reference numeral 32 denotes a video memory including a left-eye memory 32L and a right-eye memory 32R. Reference numeral 33 denotes a combined drive signal generation circuit. The video memory 32 and the combined drive signal generation circuit 33 constitute a liquid crystal panel drive circuit 30. Outputs of the image signal sources 31L and 31R corresponding to the left and right eyes are stored in the memories 32L and 32R for one screen.

In the figure, L1, L2, L3,.
And n rows of image data for the left eye stored in the image data. R1, R2, R3,... Rn are image data for n rows for the right eye held in the memory 32R. The data held in the video memory 32 is alternately converted into data for the left eye and data for the right eye on a row-by-row basis in the combined drive signal generation circuit 33, and the rows LC 1, LC 2, LC 3,.
..., output to LCn in order.

FIG. 4A shows a change in the display state of the liquid crystal panel 6. In the figure, Tf is the field period, and in the first field, the first period is (L1, R2, L3, R4,..., Ln-1, Rn).
The image is displayed in order from the row to the n-th row, and in the second field, the image is sequentially displayed from the first row to the n-th row as (R1, L2, R3, L4,..., Rn-1, Ln). indicate. Similarly, the next screen data is written in the third field and the fourth field, and this is repeated thereafter. According to this data display method, the image for the left eye and the image for the right eye are interlaced, respectively, and the display of one screen is completed in a total of two fields. Therefore, for example, the image for the left eye and the image for the right eye are alternately displayed for each field. In comparison, flicker (flicker) of an image can be reduced.

In FIG. 3, the polarization switching element 21 outputs a signal from each row (C 1, C 2, C 3,.
n) The state is switched. FIG. 4B shows the change over time in the state of the polarization switching element 21. In the figure, Tf is the field period, and Th is the horizontal scanning period. In the figure, symbols (+,-) indicate two states of voltages applied to the respective row electrodes for setting the polarization switching state for the left eye and the right eye, respectively. It should be noted that the symbols (+,-) are not necessarily the signs of the voltage applied to the liquid crystal, but are merely used for explaining the two states. In the first field, in synchronization with the horizontal scanning cycle, (+,-, +,-, ...
(, +,-), And the polarization switching state corresponding to the left-eye and right-eye data of the first field in FIG. In the second field, the first field is synchronized with the horizontal scanning cycle.
The state changes in order from the row to (-, +,-, + ...,-, +), and FIG.
The polarization switching state corresponding to the right-eye and left-eye data in the second field of a. Thereafter, in the odd and even fields,
Signals similar to those in the first field and the second field are repeatedly applied to the polarization switching element 21.

In FIG. 3, the signal sources 31L, 31
The operations of the R, the video memory 32, the combined drive signal generation circuit 33, and the scanning circuit 40 are performed in synchronization with the common horizontal synchronization signal Hsync and the common field synchronization signal Fsync.

When the principal rays emitted from the corresponding rows of the liquid crystal panel and the polarization switching element in the projection light are shifted, crosstalk occurs in the projected images of the left and right eyes. Therefore, a preferred setting of the row pitch of the liquid crystal panel 6 and the row pitch of the polarization switching element 21 will be described with reference to FIG. FIG.
Is a known telecentric projection lens in which the entrance pupil on the liquid crystal panel side is located at infinity, and the principal ray on the liquid crystal panel 6 side is parallel to the optical axis of the projection lens 8 as shown by an arrow. Has become. In the drawing, Pl and Pe are the row pitches of the liquid crystal panel 6 and the polarization switching element 21, respectively. In this case, Pl = Pe
It can be seen that the relationship (1) eliminates the displacement of the liquid crystal panel and the row position of the polarization switching element in the projected image.

The projection lens 8 shown in FIG. 6B is a known non-telecentric projection lens in which the entrance pupil 8I on the liquid crystal panel 6 side is located at a finite distance, and the principal ray on the liquid crystal panel side is the entrance pupil 8I as shown. Incident on the center of. Pl / Pe = L1 / L2 (2) in order to eliminate the displacement of the row position between the liquid crystal panel and the polarization switching element in the projected image.
And it is sufficient. Here, Pl is the row pitch of the liquid crystal panel, P
e is the row pitch of the polarization switching element, L1 is the optical distance from the image display surface of the liquid crystal panel to the entrance pupil 8I, and L2 is the optical distance from the polarization switching element to the entrance pupil 8I. When the specifications of the projection lens and the arrangement of the liquid crystal panel and the polarization switching element are determined, the row pitch may be determined so that the ratio of Pl to Pe satisfies the expression (2).

<Second Embodiment> In the configuration of FIG. 1, the dichroic prism 7 is used for synthesizing the three primary colors, but this is replaced with two dichroic mirrors 70 as shown in FIG.
G, 70B. In the figure, 70G is a dichroic mirror that reflects green and transmits red, and 70B is a dichroic mirror that reflects blue and transmits green and red. Other components are the same as those in FIG. The driving method of the liquid crystal panel and the polarization switching method described in FIGS. 3, 4 and 6 and the setting method of the row pitch between the liquid crystal panel and the polarization switching element are the first.
This is the same as the embodiment. It is clear from the description of the first embodiment that the effect of the present invention does not change even in this case.

<Third Embodiment> In the configuration of FIG. 1, the liquid crystal panels 6R, 6G, 6B and the polarization switching elements 21R, 21R
Although G and 21B have been described as separate elements, they may actually be integrally formed. FIG. 9 shows the configuration in that case. In FIG. 9, reference numeral 6 denotes a TN liquid crystal panel for displaying images, which is composed of a liquid crystal cell 6L having polarizing plates 6P and 6A and a matrix electrode 6M. Reference numeral 21 denotes a polarization switching element, which includes two transparent substrates 21F and 21R, a liquid crystal layer sandwiched between the substrates, and a row electrode 21C. The polarization switching element 21 and the liquid crystal panel 6 are integrally formed so as to be in contact with each other. By mounting three sets of such a liquid crystal panel and a polarization switching element integrally on the same optical system as in FIGS. 1 and 7, the optical system can be downsized.
In addition, since the relative positioning of the liquid crystal panel and the polarization switching element is not required when assembling the apparatus, the assembling work is simplified. Moreover, since the surface of the matrix 6M serving as the image display surface of the liquid crystal panel and the surface of the row electrode 21C of the polarization switching element are brought close to each other, when the projected image is focused, the blur of the row electrode 21C can be reduced. As left /
Crosstalk between right eye images can be reduced. Incidentally, only the polarizing plate 6P on the incident side may be separated for cooling the element. Since the polarizing plate 6P does not particularly have a pixel structure or the like, even if the polarizing plate 6P is formed separately, the trouble of adjustment is not particularly increased.

<Modification> In the above embodiment, an example has been described in which the direction of the linearly polarized light of the right-eye and left-eye projection images is switched by 90 ° for projection. However, a second conventional example will be described with reference to FIG. As described above, it is also possible to switch between right-handed circularly polarized light and left-handed circularly polarized light for projection. In this case, as shown by a broken line in the projection optical system of FIGS.
May be inserted in front of. The optical axis of the λ / 4 plate 22 to be inserted is arranged so as to form an angle of 45 ° with the polarization direction of the transmitted light of the polarization switching element. Also, three λ / 4 plates are placed immediately after the polarization switching elements 21G, 21B and 21R (on the side of the projection lens).
By inserting one by one, the amount of phase shift of the λ / 4 plate can be optimized according to the main wavelength of each primary color, so that the color change of the projection light is advantageously reduced. As the circularly polarized glasses worn by the observer, circular polarized glasses similar to those shown in FIG. 11B in the conventional example may be used. The advantage of circularly polarized light projection is
As in the conventional example, crosstalk does not occur even if the observer tilts the head to the left or right.

In FIGS. 1 and 7, the exit-side polarizing plate (polarizing plate 6A in FIG. 2) of the TN mode liquid crystal panels 6R, 6G, 6B may be omitted. In this case, there is a feature that the projected image can be viewed only by the wearer of the polarized glasses.
This is the same for the circularly polarized light projection.

In FIG. 2, the polarization axes of the incident-side polarizing plate 6P and the outgoing-side polarizing plate 6A of the TN mode liquid crystal panel 6 are arranged to be orthogonal to each other. Even if the two polarization axes are arranged in parallel, it is still possible to observe a stereoscopic image according to the present invention.

As a polarization switching element, TN (Tw
(Ised Nematic) liquid crystal cells may be used. FIG. 8 is an explanatory view showing the operation principle of a modification (TN liquid crystal cell) of the polarization switching element used in the present invention. In the figure, the TN liquid crystal cell 21 is a transparent substrate 21F having a transparent electrode and an alignment layer provided on the inner surface. , 21R and a liquid crystal 21L injected between them. As shown in FIG. 8A, the liquid crystal 21 is oriented so that the major axis direction of the liquid crystal molecules is rotated by 90 ° from the substrate 21F to the substrate 21R when no voltage is applied. The direction is rotated by 90 ° along the twist of the liquid crystal molecules and transmitted. On the other hand, when a voltage V of a certain value or more is applied to the transparent electrode as shown in FIG. 8B, the twisted orientation of the liquid crystal 21L is lost, and the polarization plane of the incident light Li is transmitted without rotation. By utilizing the properties of the TN liquid crystal cell as described above, no voltage is applied,
Switching of the polarization plane can be realized in two states of application. When a TN liquid crystal cell is applied to the present invention, it is needless to say that at least one side of the transparent electrode should be periodically divided vertically. As described above, if the TN liquid crystal panel is used for the image display panel and the TN liquid crystal cell is used as the polarization switching element, a part of the liquid crystal cell manufacturing process can be shared, and the cost of the projection display device is reduced. Further, if both the liquid crystal cells for the liquid crystal panel of the image element and the liquid crystal cell for the polarization switching element are formed using TN liquid crystal cells having matrix electrodes in the vertical / horizontal directions, both cells can be made the same, and the cost reduction effect can be obtained. It becomes even more noticeable.

[0059]

As described above, according to the present invention, a novel stereoscopic image capable of displaying parallax images for the right and left eyes by switching the polarized light emitted from the light valve (liquid crystal panel for image display) line by line. It is possible to realize a projection type display device capable of displaying. The present apparatus is small in size because a single projector can project a stereoscopic image, and does not require adjustment at the time of installation, such as superposition adjustment of left and right parallax images.

Further, since the output lights of the plurality of light valves are synthesized and projected, a sufficient number of pixels can be secured, and a high-definition and high-luminance stereoscopic image can be displayed.

Further, the combined light of the plurality of light valves is represented by λ
Since the light can be converted into circularly polarized light that rotates in the opposite direction for the right and left eyes and projected by the / 4 plate, the crosstalk between the left and right parallax images can be reduced even if the observer tilts the head left and right.

Also, by switching the state of the polarization switching element with an electrode having a periodic structure so as to alternately output left-eye and right-eye images for each row, a highly reliable three-dimensional image without a mechanical polarization switching mechanism. A projection type display device for display can be realized.

Further, since the polarization of the display image of the TN mode liquid crystal can be controlled by a polarization switching element made of a ferroelectric liquid crystal which operates at high speed, a stereoscopic image with high contrast can be displayed.

Further, since the polarization of the display image of the TN mode liquid crystal can be controlled by the polarization switching element using the TN mode liquid crystal, the manufacturing process of the liquid crystal cell can be made common and a relatively inexpensive projection display device can be obtained.

Further, since the right-eye image and the left-eye image can be displayed in an interlaced manner by the operation of the light valve driving circuit, the polarization switching element and the scanning circuit, a three-dimensional display with less flicker is possible.

Further, the combination of the telecentric projection lens, the light valve having the same vertical electrode period, and the polarization switching element enables the display of each row to be reliably sent to the right eye or the left eye, and a three-dimensional image with small crosstalk. Display is possible.

The ratio of the distance from the entrance pupil position of the non-telecentric projection lens to the light valve and the polarization switching element is equal to the ratio of the vertical electrode period of the light valve and the ratio of the vertical electrode period of the polarization switching element. By doing so, the display of each line can be reliably sent to the right eye or the left eye, and a three-dimensional image with small crosstalk can be displayed.

Further, since the light valve and the polarization switching element are integrally formed, assembly of the projection type display device is facilitated, and the projection type display device is compact and has small crosstalk between left / right parallax images. Is obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an optical system of a projection display according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an arrangement of a liquid crystal panel and a polarization switching element, which are main parts of FIG.

FIG. 3 is a configuration diagram of a liquid crystal panel, a driving circuit of a polarization switching element, and a scanning circuit according to the present invention.

FIG. 4 is an explanatory diagram of an operation state of a liquid crystal panel and a polarization switching element according to the present invention.

FIG. 5 is an operation explanatory view of a polarization switching element (EO-HW) used in the present invention.

FIG. 6 is an explanatory diagram of a method for designing a row electrode pitch of a liquid crystal panel and a polarization switching element according to the present invention.

FIG. 7 is a configuration diagram showing an optical system of a second embodiment of the projection display apparatus according to the present invention.

FIG. 8 is an operation explanatory view of a modification (TN liquid crystal cell) of the polarization switching element used in the present invention.

FIG. 9 is a diagram showing a configuration of an integrated liquid crystal panel / polarization switching element used in a third embodiment of the present invention.

FIG. 10 is a configuration diagram of a projection display device according to a first conventional example.

FIG. 11 is a configuration diagram of a projection display device according to a second conventional example.

[Explanation of symbols]

Reference Signs List 1 light source 6, 6R, 6G, 6B light valve (first liquid crystal panel) 6M pixel electrode 6P, 6A polarizing plate 7, 70B, 70G combining means 8 projection lens means 21, 21R, 21G, 21B polarization switching means (second
21C row electrode 22 λ / 4 plate 30 light valve drive circuit 40 scanning circuit

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-2-144516 (JP, A) JP-A-3-264919 (JP, A) JP-A-1-217390 (JP, A) JP-A-63- 158525 (JP, A) JP-A-62-191824 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1335 G02F 1/133 G02F 1/13 505 G02B 27/22

Claims (8)

(57) [Claims] 2. The method according to claim 1, wherein each of the light beams passes through a different polarization state.
A first polarizer for a first eye and a second polarizer for a second eye
Is viewed by an observer using polarized glasses having
A projection display device for projecting an image having a light source and pixels arranged in a plurality of rows and a plurality of columns.
Convert the emitted light beam into linearly polarized light and
A light valve that modulates in a plane including the pixels of the first and second positions, and an image for a first eye is displayed on an odd-numbered row of the light valve.
And a second eye picture on the even row of the light valve.
A first display mode for displaying an image, and the light valve
The image for the second eye is displayed on odd rows of
The first eye image is displayed on the even-numbered row of the light valve.
2 display mode is switched every field cycle
A light valve driving circuit for driving the light valve
Path and a plurality of row electrodes corresponding to the row of the light valve on a one-to-one basis.
A row, and the incident light is changed according to a voltage applied to the row electrode.
The first state of passing the light without changing the polarization direction,
The second state in which the polarization direction is rotated by 90 ° and passed through
Polarization switching means that can be set for each row and odd-numbered rows of the polarization switching means in the first state
In both cases, the even rows of the polarization switching means are set to the second state.
The first transmission mode and the odd-numbered rows of the polarization switching means.
In the second state, an even number of the polarization switching means
A second transmission mode for bringing the row into said first state.
Polarization switching means scanning circuit that switches in synchronization with the field cycle
And emitted from the light source, the light valve and the polarized light
Projection lens hand that enlarges and projects the light beam that has passed through the switching means
Projection display device characterized by having a stage. 2. A light-emitting device comprising: a plurality of light valves; a plurality of light valves; an output side of each of the plurality of light valves; a polarization switching unit; and a combining unit for combining and projecting output lights of the respective polarization switching units. The projection display device according to claim 1, wherein: 3. A light valve, comprising: a plurality of light valves; and a plurality of light valves each having an output side provided with the polarization switching means. The output light of each polarization switching means is clockwise circularly polarized according to a polarization switching state. Λ / which converts light into left-handed circularly polarized light
2. The projection display device according to claim 1, comprising four plates, and combining and projecting output lights of the respective polarization switching means. 4. The light switch comprises a cell in which a TN mode liquid crystal is sealed, and a first liquid crystal panel comprising a polarizing plate disposed on both an illumination light incident side or an illumination light incident / exit side. Consists of a second liquid crystal panel having a structure in which a ferroelectric liquid crystal is sandwiched between two transparent substrates,
In the ferroelectric liquid crystal, the orientation of the liquid crystal molecules is switched between state 1 and state 2 according to the polarity of the applied voltage. In state 1, the polarization direction of the light emitted from the first liquid crystal panel is transmitted without rotating. 2. The projection display device according to claim 1, wherein, in the state 2, the light emitted from the first liquid crystal panel is transmitted by rotating the polarization direction by 90 degrees. 5. The light switch comprises a cell in which a TN mode liquid crystal is sealed, and a first liquid crystal panel comprising a polarizing plate disposed on both the illumination light incident side or the illumination light incidence / emission side. Consists of a second liquid crystal panel having a structure in which a TN mode liquid crystal is sandwiched between two transparent substrates, and the TN mode liquid crystal of the second liquid crystal panel switches between two states, state 1 and state 2, according to the applied voltage. In the state 1, the light emitted from the first liquid crystal panel is transmitted without rotating the polarization direction, and in the state 2, the light emitted from the first liquid crystal panel is transmitted by rotating the polarization direction by 90 °. The projection display device according to claim 1, wherein: 6. The projection lens means is a telecentric lens system in which an off-axis chief ray on the light valve side is parallel to an optical axis of the projection lens means, and the light valve has a period in an upward and downward direction. specific multiline has row electrodes, vertical row electrode means switching the row electrodes of the light valve polarized light
2. The projection display device according to claim 1, wherein the arrangement pitches are equal. 7. The projection lens unit is a non-telecentric lens system, and the light valve has a plurality of rows of periodic electrodes having a pitch Pl in the vertical direction . The row electrodes are vertically arranged at a pitch Pe , and the optical distance from the polarization switching unit to the entrance pupil of the projection lens unit is L2, and the optical distance from the light valve to the entrance pupil of the projection lens unit is L1. 2. The projection display device according to claim 1, wherein said Pl and Pe satisfy the following relationship. Pl / Pe = L1 / L2 8. The projection display device according to claim 1, wherein the light valve and the polarization switching unit are in contact with each other to be integrally formed.