JP2003259395A - Stereoscopic display method and stereoscopic display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem in a conventional stereoscopic display apparatus employing a liquid crystal panel for a display monitor that it causes a sense of fatigue to a user due to a double image or flickering because the screen is dark and the response is slow in comparison with those of a display apparatus employing a CRT. <P>SOLUTION: After writing each of R, G, B fields for the left eye image for one frame of 16.6 msec, similarly each field is written also for the right eye image. At that time, black is entirely written between fields, and each field is completed within a time of 16.6/6=2.8 msec or below from the writing, backlight emission and full back writing. The full screen back write time t5 may be at least a time t4 or over required for storing the liquid crystal. An OCB liquid crystal, which has a high modulation rate of the liquid crystal and compatibility between the high modulation rate and high speed response, is proper to the liquid crystal panel 12. For example, a trailing time t4 in the high speed OCB liquid crystal is selected to be 0.5 msec or below and the full screen black write time t5 can be set to be 0.5 msec that is nearly equal to the time t4. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stereoscopic display method and a stereoscopic display device for observing a stereoscopic image, and more particularly to a flat panel type stereoscopic display device with high brightness.

[0002]

2. Description of the Related Art Various stereoscopic display methods have been proposed in the past, and typical ones of them are liquid crystal shutter glasses and parallax-free glasses.
Barrier method, lenticular method, etc. can be mentioned.

However, in either method, in order to obtain a high-quality stereoscopic image that maintains the resolution, it is necessary to handle both the image for the left eye and the image for the right eye, that is, twice the amount of video information. Therefore, it is necessary to solve the problems that the brightness is reduced to half or less, high-speed switching of the left and right images is required, and the like.

In Japanese Patent Laid-Open No. 2000-275575,
In the liquid crystal shutter glasses method, a stereoscopic display device capable of obtaining a bright stereoscopic image has been published. Figure 10
FIG. 1 is a diagram showing a configuration example of a stereoscopic image display device proposed in Japanese Patent Laid-Open No. 2000-275575.

The stereoscopic video signal 104 is converted into a time-division video signal by the scan converter 105, and the monitor 1
Images of the left and right eyes are displayed in time-division 06. The light-scattering liquid crystal glasses 108 are provided with a light-scattering liquid crystal element 109 in each of the left eye portion and the right eye portion thereof.
When the field of the image for the left eye is displayed on, the liquid crystal element of the left eye portion is set to the transmissive state and the liquid crystal element of the right eye portion is set to the scattering state.

As described above, by using the light-scattering type liquid crystal display element, the transmittance when the liquid crystal element transmits the light is remarkably improved, and a bright stereoscopic image can be observed.

[0007]

However, in the case of the stereoscopic display device as described above, the following problems remain. That is, (1) When a liquid crystal panel is used as a monitor, it is necessary to increase the brightness of the backlight to obtain a bright image, resulting in a large power consumption. Also,
There is a limit to improving the brightness as compared with the CRT.

(2) When a left image and a right image are alternately displayed on a monitor using a liquid crystal panel, an afterimage remains on a liquid crystal having a slow response, and a double image or flicker appears, resulting in a stereoscopic image. It causes a feeling of fatigue peculiar to the eyes.

[0009]

In order to solve the above problems, the stereoscopic display method and the stereoscopic display device of the present application have the following configurations. That is, (1) display means for alternately assigning an image for the left eye and an image for the right eye for each field and displaying them on the same screen in time sequence, and synchronizing with switching between the image for the left eye and the image for the right eye. A stereoscopic display method for observing a stereoscopic image by selectively viewing a left-eye image for the left eye and a right-eye image for the right eye, wherein the display means is an optical switching means and an optical switching means. A three-dimensional display method for performing color display with additive color mixture temporally, including a light source for irradiating the light source and a color of the light source in a time-sequential manner, and driving means for controlling the transmission or reflection state of the optical switching means in synchronization with the light source. did.

(2) Display means for alternately assigning an image for the left eye and an image for the right eye for each field and displaying them on the same screen in time sequence, and for switching between the image for the left eye and the image for the right eye. A stereoscopic display device for observing a stereoscopic image by selectively viewing an image for the left eye for the left eye and an image for the right eye for the right eye in synchronization, wherein the display unit of the display means is an image for the left eye. The three-dimensional display device includes a left-eye pixel portion for displaying an image and a right-eye pixel portion for displaying an image for the right eye.

(3) The display means comprises a liquid crystal panel, a light source for irradiating the liquid crystal panel, and a driving means for time-sequentially switching the color of the light source and controlling the transmission or reflection state of the liquid crystal panel in synchronism therewith. The three-dimensional display device is a field sequential color system that performs color display with additive color mixing over time.

(4) A display means for displaying an image for the left eye and an image for the right eye on the same screen and a parallax barrier are provided, and the image for the left eye is provided for the left eye and the image for the right eye is provided for the right eye. A stereoscopic display method for observing a stereoscopic image by selectively seeing an image for the right eye, wherein the display means comprises an optical switching means, a light source for irradiating the optical switching means, and a color of the light source in time sequence. Switching, and provided with drive means for controlling the transmission or reflection state of the optical switching means in synchronization therewith,
A three-dimensional display method is adopted in which color display is performed by temporally additive color mixing.

(5) A display means for displaying an image for the left eye and an image for the right eye on the same screen and a parallax barrier are provided, and the left eye image is provided for the left eye and the right eye image is provided for the right eye. A stereoscopic display device for observing a stereoscopic image by selectively viewing an image for the right eye, wherein a display unit of the display means includes a pixel unit for the left eye for displaying the image for the left eye, and an image for the right eye. And a pixel unit for the right eye for displaying, the display means is a liquid crystal panel,
A field sequential color system that includes a light source that illuminates the liquid crystal panel and a driving unit that switches the color of the light source in a time-sequential manner and controls the transmission or reflection state of the liquid crystal panel in synchronism with that, and performs color display with additive color mixture over time. And a liquid crystal display device.

(6) The parallax barrier is composed of optical switching means.

(7) The light switching means is composed of a light scattering type liquid crystal element.

(8) The optical switching means is composed of OCB mode liquid crystal in which a phase compensating plate is arranged in front of the bend alignment liquid crystal.

(9) A standard display mode for displaying a normal two-dimensional image by displaying the same image on the image for the left eye and the image for the right eye is provided.

(10) A configuration is provided in which switching means is provided for freely switching between a stereoscopic display mode for displaying a stereoscopic image and a standard display mode for displaying a normal two-dimensional image.

(11) The display mode is automatically switched to one of the standard display mode and the stereoscopic display mode depending on the type of video signal.

(12) Before and after switching the display mode,
The configuration is such that the correction means is configured so that the brightness of the display means is substantially the same.

(13) The display means is composed of OCB mode liquid crystal in which a phase compensating plate is arranged in front of the bend alignment liquid crystal.

(14) The display means is a liquid crystal panel,
The liquid crystal layer was made of ferroelectric liquid crystal.

(15) The display means is a liquid crystal panel,
The liquid crystal layer was made of antiferroelectric liquid crystal.

(16) The phase difference Δn · d (retardation) of the liquid crystal layer is 600 nm or more and 900 nm or less, and the liquid crystal layer is made of a cyano material.

(17) The cyano material content is set to 10% or less.

(18) The cyano material has a constitution containing a PCH (phenyl cyclohexane) group.

(19) The cyano material is made of a cyano material containing a terphenyl group.

(20) The liquid crystal layer has a thickness of 2.5 μm or more and 3.5 μm or less.

(21) The refractive index anisotropy Δn of the liquid crystal layer is 0.
The configuration is 24 or more.

(22) The viscosity coefficient η of the liquid crystal layer is 30 mPa.
-It is the composition which is above s and below 60 mPa-s.

(23) A black voltage for applying a voltage for displaying black in a liquid crystal panel is inserted and driven at a constant rate in one frame, and the liquid crystal layer contains a PCH (phenyl cyclohexane) group. The composition is a cyano material.

(24) The driving frequency is set to 300 Hz or less.

(25) A black voltage for applying a voltage for displaying black in a liquid crystal panel is inserted at a constant rate in one frame and driven at a driving frequency of 360 Hz or higher, and the liquid crystal layer has a terphenyl group. The composition is a cyano-based material to be contained.

(26) The liquid crystal layer is made of a fluoro material.

(27) The liquid crystal layer is made of a fluorotolan material.

(28) The light source used for the display means is LE
The structure is composed of D elements.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) A first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an overall view showing the configuration of a stereoscopic display device according to the first embodiment of the present invention. In FIG.
1 is a stereoscopic display device, 2 is a display monitor, 3 is a polarizing plate, 4
Is a liquid crystal shutter, 5 is a retardation plate, 6 is polarized glasses, 7
Is an image signal, 8 is an image processing unit, 9 is a display monitor driving circuit, and 10 is a synchronizing circuit.

FIG. 2 is a plan view showing the structure of the display section in the first embodiment of the present invention, and FIG. 2A is a pixel structure consisting of two types of pixels for the left eye and pixels for the right eye. In this case, FIG. 2B shows a case of a pixel configuration including only one type. In FIG. 2, 11 is a pixel portion of the display monitor 2,
Reference numeral 11a is a pixel for the left eye, and 11b is a pixel for the right eye.

In the image processing unit 8 to which the image signal 7 for stereoscopic vision is input, after being processed into an image signal for the left eye and an image signal for the right eye, the image signal is sent to the display monitor drive circuit 9 for display. Image signals for the left eye and image signals for the right eye are alternately assigned to each pixel unit 11 of the monitor 2 for each field, and the image for the left eye and the image for the right eye are displayed in time sequence in the display monitor 2 Will be displayed alternately on the same screen. A polarizing plate 3 and a liquid crystal shutter 4 are provided on the front surface of the display monitor 2.
The stereoscopic image is observed by selectively viewing the image for the left eye transmitted through the polarizing plate 3 and the liquid crystal shutter 4 with the left eye and the image for the right eye with the right eye using the polarizing glasses 6. To do. Here, the switching of the liquid crystal shutter 4 is performed according to the switching between the image for the left eye and the image for the right eye.
The polarization states are switched so as to synchronize with each other.

As the pixel configuration of the display monitor 2 at this time, in the case of the pixel configuration of two types of pixels for the left eye and the pixel for the right eye of FIG. 2A, only one type of FIG. 2B is used. There are two types of pixel configurations consisting of TN on the display monitor
If the response is slow, such as when using mode LCD,
(A) If the response is fast, a bright image can be obtained by selecting the pixel configuration of FIG. 2 (b). When a field sequential color liquid crystal panel as described later is used, RGB sequential driving is required in addition to switching between the left-eye image and the right-eye image, so 16.6 / 6 =
Since a very high-speed response of 2.8 msec is required, the response time is doubled by applying the pixel configuration of FIG.
It may be delayed by 6 msec, and the selection range of the liquid crystal panel configuration is expanded.

The switching of the liquid crystal shutter 4 is configured to be synchronized by the synchronizing circuit 10 according to the types of the left-eye image signal and the right-eye image signal sent from the image processing unit 8. Further, the retardation plate 5 is for adjusting the color tone due to the retardation of the liquid crystal shutter 4.

When a liquid crystal display is used as the display monitor 2 in order to save space, the most popular transmission type TN mode liquid crystal is generally used.
However, in order to obtain a high-quality stereoscopic image that maintains the resolution, it is necessary to handle both the left-eye image and the right-eye image, that is, double the amount of video information, so the brightness is less than half. It is necessary to solve the problems such as: fast switching between left and right images, and so on.

Further, in the case of the TN mode liquid crystal, it is difficult to obtain a high brightness like a CRT, and it is necessary to increase the brightness of the backlight, which results in an increase in power consumption.
The total rise time and fall time of the TN mode liquid crystal (hereinafter referred to as "response time" and referred to as τr + d) is about 16 msec even at high speed, and the left and right images are displayed within one frame of 16.6 msec. Is difficult to do.

In order to solve the above problems, in the first embodiment, a field-sequential color drive type liquid crystal panel of OCB mode liquid crystal in which a phase compensating plate is arranged in front of bend alignment liquid crystal on the display monitor 2 is used. Using. The OCB mode liquid crystal in the first embodiment can have a high-speed response in 3 msec or less while ensuring high transmittance and reliability. The configuration will be described below.

FIG. 3A is an enlarged cross-sectional view showing the structure of the liquid crystal panel used in the stereoscopic display device according to the first embodiment of the present invention. FIG. 3B is an enlarged plan view of the pixel portion showing the configuration of the liquid crystal panel used in the stereoscopic display device according to the first embodiment of the present invention.

In FIG. 3, 12 is a liquid crystal panel, 13 is a backlight, 14 is an array substrate, 15 is a counter substrate, 1
6 is a liquid crystal layer, 17 is a counter electrode, 18 is a pixel electrode, 19 is a video signal line which is connected to the pixel electrode 18 and gives a video signal,
20 is a scanning signal line, 21 is a semiconductor switch element, 22 is a first insulating layer, 23 is a second insulating layer, 24 is a black matrix layer, 25a is an alignment film formed on the inner surface of the array substrate 14, and 25b is a counter substrate 15. Alignment film formed on the inner surface of
26 is an LED light source, 26a is a red LED, 26b is a green LED, 26c is a blue LED, 27 is a reflector, and 28 is a light guide plate.

The operation will be described below with reference to FIG.

First, a conductor made of Al, Ti or the like is formed on the array substrate 14, and the scanning signal line 20 is patterned into a predetermined shape. After the first insulating layer 22 is formed on the first electrode group thus formed, the first insulating layer 22 is formed.
A semiconductor switch element 21 including an a-Si layer and an n + type a-Si layer (both not shown) is formed on a predetermined portion of the. Further, a conductor made of Al, Ti or the like is formed on a predetermined portion of the first insulating layer 22 and the semiconductor switch element 21, and a second electrode group made of the video signal line 19 is patterned into a predetermined shape.

Next, the second insulating layer 23 made of SiNx or the like is formed on the array substrate 14 on which the second electrode group is formed. The second insulating layer 23 also serves as a protective film that protects the semiconductor switch element 21.

Further, the pixel electrode 18 is formed of an ITO film which is a transparent conductor.

After that, the array substrate 14 and the counter substrate 1
On the film 5, alignment films 25a and 25b made of polyimide or the like are formed in order to align the arrangement of the molecules of the liquid crystal layer 16.

In the OCB mode liquid crystal display element like the invention of the present application, the array substrate 14 and the counter substrate 15 are rubbed, but the directions are parallel to each other so that they are parallel.

The counter substrate 15 is provided so as to face the array substrate 14, and the counter electrode 17 and the black matrix layer 24 are formed in a predetermined pattern.

The array substrate 14 and the counter substrate 15 thus manufactured each have an initial orientation in a predetermined direction, the peripheral portions thereof are bonded with a sealant, and then the liquid crystal layer 16 is injected and sealed. .

The semiconductor switch element 21 is the video signal line 19
Also, on / off control is performed by a drive signal input from the scan signal line 20. Then, the semiconductor switch element 21
An electric field is generated by the voltage applied between the pixel electrode 18 connected to the counter electrode 17 and the counter electrode 17 to change the orientation of the liquid crystal layer 16 to control the brightness of each pixel and display an image.

In the liquid crystal display device of the present application, the liquid crystal molecules are in a splay alignment state in which the liquid crystal molecules are aligned substantially in parallel when no voltage is applied in the initial stage, and the alignment of the liquid crystal is transferred to the bend alignment state used for display. In order to carry out this transition, a relatively large transition voltage, for example, about 25 V was applied to the liquid crystal layer.

The OCB mode liquid crystal display element has a substrate and a liquid crystal, and displays by applying a voltage to the liquid crystal, and a zero-voltage alignment state when no voltage is applied to the liquid crystal and a display alignment used in the display state. Different from the state, it is a kind of liquid crystal display element that makes a transition from a zero voltage alignment state to a display alignment state by applying a transition voltage, and can realize a display with a fast response and a wide viewing angle.

Since the first embodiment is of the field sequential color display system, the color filter which is indispensable for a normal active matrix system color liquid crystal display device is not necessary. Instead, backlight 1
3 requires LED light sources 26a, 26b, and 26c capable of emitting red (R), green (G), and blue (B) colors.

The light emitted from the LED light source 26 is reflected by the reflection plate 27 and is incident on the liquid crystal panel 12 while being repeatedly reflected by the light guide plate 28. In this way, the LED light sources 26a, 26b, 26 of RGB colors for irradiating the liquid crystal panel 12 are provided.
c is switched in time sequence, and the liquid crystal panel 1 is synchronized with it.
By controlling the light transmission state of No. 2, color display is performed by temporally additive color mixing.

With the above configuration, the transmittance of the panel is remarkably improved as compared with the conventional method using a color filter, so that not only a bright liquid crystal panel can be obtained, but also an LED of high color purity is used as the light source 26. By using, N
It is possible to realize a much higher color reproducibility than the conventional method in which the TSC ratio is 100% or more.

Next, the operation and effect of the panel structure according to the first embodiment will be described.

Japanese Unexamined Patent Publication No. 11-14988 proposes to use OCB mode liquid crystal for a liquid crystal panel. The OCB mode liquid crystal is capable of high-speed response as compared with other liquid crystal modes such as TN, but it is still 3 mse.
In order to realize a high-speed response of c or less, it is necessary to take measures such as reducing the cell gap to a narrow gap of 2 μm or less or reducing the viscosity of the liquid crystal material.

However, in terms of practical use, it is necessary to secure not only high-speed response but also the transmittance of the panel as much as possible and the reliability at the same time. The inventors of the present application examined the conditions of the OCB liquid crystal panel configuration for achieving both high-speed response, high transmittance, and reliability.

First, in order to achieve both high-speed response and high transmittance, a cyano containing a PCH (phenyl cyclohexane) group capable of increasing the birefringence anisotropy Δn to 0.2 or more. The viscosity of liquid crystal materials, which are roughly classified into four types, that is, cyano type, fluor type, and fluoro tolan type containing a terphenyl group, was reduced. In addition, in order to determine only the dependency of the liquid crystal material on the transmittance, the transmittance of the light which is modulated by the liquid crystal is excluded by excluding the influence of the transmittance of the polarizing plate or the color filter (hereinafter, the liquid crystal modulation rate. I said).

In a cyano material, when the cyano content is 18%, the birefringence anisotropy Δn = 0.28 and the viscosity η
= 44 mPa · s, and the cell gap 2.
Response time τr + d = 1.5msec on 6μm panel,
A liquid crystal modulation rate of 85% was obtained. However, 60 ℃, 90%
In the high temperature and high humidity test, the voltage holding ratio was decreased by 10% or more after 500 hours compared to the initial stage, and there is a problem in reliability, which is not suitable for practical use.

A birefringence anisotropy Δ of a liquid crystal containing a terphenyl group was used as a material whose cyano content was suppressed to 10%.
n = 0.28, viscosity η = 51 mPa · s, liquid crystal containing PCH group, birefringence anisotropy Δn = 0.27, viscosity η =
A physical property value of 45 mPa · s was obtained, and the cell gap was 2.6.
With a panel of μm, a response time τr + d = 2 msec and a liquid crystal modulation rate of 70% were obtained. Although the performance is slightly inferior to the material with a cyano content of 18%, no decrease in the voltage holding ratio is seen even after 500 hours in the high temperature and high humidity test at 60 ° C and 90%, and the reliability is high. It turned out that there was no problem in terms of. Further, even if the cyano content is 10%, the viscosity η = 37 mPa · s, the viscosity η = 34 mPa · s, and the viscosity η = 29 mPa · s are 60 ° C. and 90%, respectively.
In high temperature and high humidity test, the voltage holding ratio was 50% compared to the initial value.
A decrease of 10% or more was observed after 0 hour. This is due to the viscosity reducing material contained to reduce the viscosity, which means that reliability and high-speed response are in a trade-off relationship.

With respect to the fluoro-based material, physical properties such as birefringence anisotropy Δn = 0.25 and viscosity η = 49 mPa · s were obtained, and the response time τ was obtained in a panel with a cell gap of 2.6 μm.
r + d = 2 msec and a liquid crystal modulation rate of 70% were obtained. Although the performance is slightly inferior to the material with a cyano content of 18%, it is 5 in the high temperature and high humidity test at 60 ° C and 90%.
It was found that the voltage holding ratio did not decrease even after the lapse of 00 hours, and there was no problem in terms of reliability.

In the fluorotolan material, physical properties such as birefringence anisotropy Δn = 0.25 and viscosity η = 43 mPa · s were obtained, and a response time τr + d = 2 msec was obtained in a panel having a cell gap of 2.6 μm. A modulation rate of 70% was obtained. Although the performance is slightly inferior to the material with a cyano content of 18%, no decrease in the voltage holding ratio is seen even after 500 hours in the high temperature and high humidity test at 60 ° C and 90%, and the reliability is high. It turned out that there was no problem in terms of.

From the above results, in any of the cyano-based materials having a cyano content of 10%, the fluoro-based materials, and the fluoro-toluan-based materials, the response time τr + d = 2 msec and the liquid crystal modulation rate 70 when the reliability was attempted. % Spec (cell gap 2.6 μm) or response time τr
It was clarified that the range of specifications (cell gap 3 μm) with + d = 2.2 msec and liquid crystal modulation rate of 80% was the practical range.

Further, in the OCB mode liquid crystal panel, there is a problem that a reverse transition state occurs in which the liquid crystal orientation changes from a bend state for displaying an image normally to a splay state. Therefore, a method has been proposed in which a black voltage (that is, in the case of normally white display, a voltage of 5 to 6 V is applied for black display) is inserted at a rate of some percentage in one frame ( Hereinafter, this insertion rate will be referred to as "black insertion rate". In order to prevent the transition to the reverse transition state, it is necessary to increase the black insertion rate, but the time for which the liquid crystal is in the on state (hereinafter referred to as “time aperture ratio”) is substantially small. Therefore, the transmittance is substantially reduced and the efficiency is reduced.

Therefore, in order to maximize the utilization efficiency of the light source when implementing the field sequential color system with the OCB mode liquid crystal, in addition to the liquid crystal modulation rate, the time aperture rate including the response time and the black insertion rate is added. You must judge by total efficiency.

Therefore, the condition of the required minimum black insertion rate was clarified. As a result, the black insertion rate depends on the type of liquid crystal material,
And it became clear that it depends on the driving frequency. It is also known that the black insertion rate differs depending on the operating temperature, and that the higher the temperature, the higher the black insertion rate is required.
Therefore, for practical purposes, the minimum black insertion rate should be determined in anticipation of use at high temperatures.

In the sample of the simple cell using each liquid crystal material, the minimum black insertion ratio required when driven at each frequency with the operating temperature of 80 ° C. was obtained. The liquid crystal materials used in the experiments showed no decrease in voltage holding ratio even after 500 hours in a high temperature and high humidity test at 60 ° C. and 90%, and it is considered that there is no problem in reliability.

From these results, the following things became clear.

(1) 100H for all materials
A peak occurs at z to 120 Hz, and thereafter, the minimum black insertion rate may become smaller as the driving frequency increases.

(2) When it is driven at a triple speed of RGB, that is, when it is driven at 180 Hz, the black insertion rate of PCH-cyano material is 10% or less, but it is 15% or more for materials other than PCH-cyano material. Black insertion rate is required.

In order to prevent color breakup, it may be necessary to drive at 6 times the speed of RGB, that is, 360 Hz, but any material may be used with a black insertion rate of 15% or less. The liquid crystal material may be determined based on the specifications of the rate.

It should be noted that black insertion is not essential for OCB mode liquid crystal of the field sequential color system, and there is also a method of setting and using a white voltage that does not cause reverse transfer without black insertion. In that case, it is not necessary to consider the driving frequency dependency of the black insertion rate, and it goes without saying that it is not necessary to select the type of liquid crystal material depending on the driving frequency.

As described above, the liquid crystal material, the cell gap,
The optimal panel configuration for each may be determined by the combination of the refractive index anisotropy Δn and the driving method.

In the first embodiment, a cyano-based material containing a terphenyl group and having a cyano content of 10% is used as the liquid crystal material, and the phase difference Δn · d (retardation) is 600 nm or more and 900 nm or less. It has a simple panel configuration. Specifically, the birefringence anisotropy Δn of the liquid crystal material is 0.25 and the cell gap is 3 μm.

Next, the details of the driving method for stereoscopic display by the field sequential color system using this OCB liquid crystal will be described with reference to FIG. Figure 4 shows RG
7 shows timing charts of writing to liquid crystal, liquid crystal response, and backlight in a stereoscopic display method by B-field sequential color driving.

In the first embodiment, R, G, and G for the image for the left eye are displayed within one frame of 16.6 msec.
After writing the B fields, the R, G, and B fields are written for the right-eye image. At this time, black is collectively written on the entire surface between each color field. this is,
Prevents color mixing between each field, and OCB
It also has an effect of preventing the liquid crystal from reversely transitioning from the bend alignment to the splay alignment.

In each field, from writing to backlight emission and full black writing, 16.6 / 6 =
It is necessary to complete in 2.8 msec or less. The time t5 of full black writing at this time may be at least the time t4 required for the liquid crystal to fall. Also,
The substantial aperture ratio that determines the brightness of the liquid crystal panel 12 is determined by the product of the liquid crystal modulation factor, the member transmittance, and the temporal aperture ratio. That is, the rise time t2 and the fall time t4 of the liquid crystal are shortened so that the R, G, and B emission times t are as short as possible.
Increasing 3 (holding time) leads to brightening the liquid crystal panel 12 and low power consumption.

Therefore, it is desirable that the liquid crystal panel 12 has a high liquid crystal modulation rate and is compatible with high-speed response.
CB liquid crystal is suitable. For example, since the fall time t4 in the high-speed OCB liquid crystal can be set to 0.5 msec or less, it is possible to set the whole surface black writing time t5 to 0.5 msec or less, which is almost the same as t4.

In the OCB liquid crystal panel of the first embodiment, the cell gap is 3 μm and the response time τr + d.
= 2.2 msec and a liquid crystal modulation rate of 80%, the specifications are suitable for this driving method.

Depending on the surrounding environment and the display image, the problem of so-called "color breakup" may become noticeable as an inherent problem of the color field sequential system. For example,
When looking at a white image, a temporal shift on the screen causes a positional shift on the retina, which is perceived as color breakup. When there is a rapidly moving scene or when the human line of sight moves rapidly (saccade), the positional deviation of the residual colors of the R, G, and B signals on the retina is R, B, or a mixture of G and R. Y
Colors such as (yellow) and C (cyan), which is a mixture of G and B, are perceived as being colored around W (white).

As one of the measures against this color breakup, there is a method of forming a frame by a frame sequential method using at least one or more intermediate color fields in addition to the three primary colors of RGB to display a color image. That is, one frame is
It is formed of R, G, and B three primary color fields and their intermediate color fields and, for example, a white (W) field (hereinafter referred to as “R”).
GBW drive ”). With such a configuration, the display time of each field is shortened and
The portion to which the color signals of the previous field generated due to the time shift is displayed in whitish. Further, the color signals B and R that are slightly added to the front and rear are very inconspicuous colors. Therefore, it is possible to display with almost no color breakup. Further, in a driving method in which two or more intermediate colors are inserted between RGB, for example, a driving method such as YBGRC or YBWGRC, the effect is more recognized against color breakup.

In the driving method according to the first embodiment,
Although the case of RGB driving has been described, the use of these driving methods can also reduce color breakup and obtain a higher quality stereoscopic image.

Further, in the first embodiment, the driving method in which black is collectively written in the entire surface between the color fields has been described as an example. However, the method in which the black field is inserted between the color fields is also the same. Needless to say, the effect of can be obtained.

In each field, from writing to backlight emission and full black writing, 16.6 / 8 =
It is necessary to complete the process within 2.1 msec or less, and it is important to increase the speed of the liquid crystal.

In this case, it is desirable to use a liquid crystal panel capable of faster response, for example, a ferroelectric liquid crystal having V-shaped characteristics or an antiferroelectric liquid crystal.

In the first embodiment, the liquid crystal shutter 4 is provided on the entire surface of the display monitor 2 and the polarizing glasses 6 are attached for observation, but the display monitor 2 has a polarizing plate. It is also possible to provide a liquid crystal shutter glasses in which only 3 is provided and the glasses are provided with the liquid crystal shutter 4 for observation.

(Embodiment 2) A second embodiment of the present invention will be described with reference to the drawings.

The major difference between the second embodiment and the first embodiment is that a parallax barrier is provided in front of the display monitor, and that no glasses are required.

FIG. 5 is an overall view showing the configuration of a stereoscopic display device according to the second embodiment of the present invention. 6 and 7 are plan views showing the principle of stereoscopic vision (parallax stereogram) in the second embodiment of the present invention.

In FIG. 5, 29 is a spacer, 30 is a parallax barrier, 31 is an observer, 32 is an observer position detecting section, 33 is a data processing section, and 34 is a phase inversion control circuit.

Similar to the first embodiment, the left-eye image and the right-eye image are alternately assigned for each field and displayed in time sequence on the same screen of the display monitor 2.

First, the principle of stereoscopic viewing will be described with reference to FIGS. 6 and 7.

FIG. 6A shows the principle of stereoscopic vision (parallax stereogram) when observing an image for the left eye with the left eye 31a. FIG. 6B is a diagram showing the positional relationship between the display monitor 2 and the parallax barrier 30 when viewed from the viewing direction at that time.

Similarly, FIG. 7A shows the principle of stereoscopic vision (parallax stereogram) when observing an image for the right eye with the right eye 31b. FIG. 7B is a diagram showing the positional relationship between the display monitor 2 and the parallax barrier 30 viewed from the observation direction at that time.

After being processed into a left-eye image signal and a right-eye image signal in the image processing section 8 to which the image signal 7 for stereoscopic vision is given, the image signal is sent to the display monitor drive circuit 9 to be displayed. In FIG. 2, the image for the left eye and the image for the right eye are displayed alternately.

The parallax barrier 30 is an electronic shutter composed of a liquid crystal panel, and is patterned in stripes so that light can be shielded. The light shield portion 30a for left eye observation and the light shield for right eye observation are provided. The portion 30b is formed. By changing the polarity by changing the polarity of the voltage applied to the electrode portion (not shown) formed on the parallax barrier 30, the left eye 31a and the right eye 31b are changed.
The structure is such that only each image can be seen alternately.

6 and 7 show the left eye pixel 1 at this time.
1 shows the positional relationship between the pixel 1a and the right-eye pixel 11b, the parallax barrier 30, and the observer 31. In order to obtain such a positional relationship, it is necessary to maintain a predetermined distance between the parallax barrier 30 and the left eye pixel 11a and the right eye pixel 11b, and in the second embodiment. Spacer 2 made of acrylic transparent resin
9 was used. When the pixel 11a for the left eye is displayed,
A barrier is formed at the position of the light-shielding portion 30a for the left-eye observation in, so that the left-eye pixel 11a can be seen only by the left eye 31a and cannot be seen by the right eye 31b. When the right-eye pixel 11b is displayed, the light-shielding portion 30b for observing the right eye in FIG.
Since the barrier is formed at the position, the right-eye pixel 11b can be seen only by the right eye 31b and cannot be seen by the left eye 31a. The phase switching at this time is performed by the phase inversion control circuit 34, and is configured to be synchronized by the synchronization circuit 10 according to the types of the left-eye image signal and the right-eye image signal sent from the image processing unit 8. ing.

Further, the stereoscopic display device 1 is provided with an observer position detection section 32, and the measured position of the observer is subjected to arithmetic processing in the data processing section 33, resulting in generation of the parallax barrier 30. This is a mechanism in which an optimal stereoscopic image is obtained by controlling the pattern to have a phase and an interval according to the position of the observer 31.

Parallax according to the second embodiment
The barrier 30 also has a function as an optical shutter. As a function of this optical shutter, it is necessary to write an image for the left eye and an image for the right eye within one frame of 16.6 msec. Therefore, 16.6 / 2 = 8.3 m
It is necessary to switch on / off in sec. But,
When a TN mode liquid crystal is used for this optical shutter, even if the response time τr + d is fast, it is about 16 msec, and since it does not follow this switching, there is a problem that it is recognized as a blur.

Therefore, in the second embodiment, the OCB is used as the liquid crystal panel for the parallax barrier 30.
Mode liquid crystal was used. OCB mode liquid crystal is 5msec
Since the following high-speed response is possible, blurring due to switching between the left and right eyes is eliminated, and since the viewing angle is wide, there is an advantage that blurring due to whitening caused by gradation inversion is eliminated. The response time τr + d at this time is 5 m
Since even about sec is sufficient, a cell gap of 5 μm to 7 μm is sufficient for the configuration of this OCB mode liquid crystal panel.

A light scattering type liquid crystal element may be used as the liquid crystal panel for the parallax barrier 30. Since the light-scattering liquid crystal element switches the light-shielding pattern by switching the scattering state / transmission state, it is not necessary to use a polarizing plate, and a very bright image can be obtained. However, since the response speed is not as fast as that of the OCB mode liquid crystal, any liquid crystal panel may be selected according to the driving method.

Furthermore, the display monitor 2 is provided with the first embodiment.
Similarly to the above, a field-sequential color drive type liquid crystal panel of OCB mode liquid crystal in which a phase compensating plate is arranged in front of the bend alignment liquid crystal was used. 3 ms while ensuring high transmittance and reliability by the same panel configuration as in the first embodiment.
A high-speed response can be achieved below ec. Since the configuration of the liquid crystal panel and the operation principle thereof at this time are the same as those in the first embodiment, they are omitted here.

With the above-described structure, the stereoscopic display method and the stereoscopic display device according to the second embodiment dramatically improve the transmittance of the liquid crystal panel as compared with the conventional method using a color filter. It is possible to obtain a flat panel type stereoscopic display device capable of providing a high-luminance and high-quality stereoscopic display method which could not be realized by the parallax barrier system.

(Embodiment 3) A third embodiment of the present invention will be described with reference to the drawings.

The major difference between the third embodiment and the first embodiment is that the three-dimensional image (three-dimensional image) and the normal image (two-dimensional image) are switched depending on the type of the input image signal. It is a point.

FIG. 8 is a block diagram showing the configuration of the input section of the stereoscopic display device according to the third embodiment of the present invention. In FIG. 8, 35 is a switching unit, 9a is a two-dimensional display driving unit, and 9b is a three-dimensional display driving unit.

First, the image processing unit 8 determines whether the input image signal is a three-dimensional image signal or a two-dimensional image signal. Based on the determined result, the switching unit 35 appropriately drives the two-dimensional display driving unit 9a or the three-dimensional display driving unit 9b provided in the display monitor driving circuit 9. In the case of a three-dimensional image signal, a stereoscopic image can be observed with the same algorithm as that of the first embodiment.

On the other hand, in the case of a two-dimensional image signal, 2
By sending the same image signal to both the left-eye pixel and the right-eye pixel by the dimensional display drive unit 9a, it is possible to display a normal image without a sense of discomfort.

(Embodiment 4) A fourth embodiment of the present invention will be described with reference to the drawings.

As in the third embodiment, the fourth embodiment is an example in which the stereoscopic image and the normal image are switched depending on the type of the input image signal. However, the parallax is placed in front of the display monitor. -It is a method with a barrier, and differs in that it does not require wearing glasses.

FIG. 9 is a block diagram showing the configuration of the input section of the stereoscopic display device according to the fourth embodiment of the present invention. In FIG. 9, 35 is a switching unit, 9a is a two-dimensional display driving unit, 9b is a three-dimensional display driving unit, and 9c is a signal correction unit.

First, the image processing unit 8 determines whether the input image signal is a three-dimensional image signal or a two-dimensional image signal. Based on the determined result, the switching unit 35 appropriately drives the two-dimensional display driving unit 9a or the three-dimensional display driving unit 9b provided in the display monitor driving circuit 9. In the case of a three-dimensional image signal, a stereoscopic image can be observed with the same algorithm as that of the first embodiment.

On the other hand, in the case of a two-dimensional image signal, the parallax barrier 30 is turned off, and the same image signal is applied to both the left eye pixel and the right eye pixel by the two-dimensional display drive section 9a. send. At this time, the aperture ratio is increased by an amount corresponding to twice the number of pixels as compared with the case of three-dimensional display, resulting in a very bright image. Therefore, when the two-dimensional image signal and the three-dimensional image signal are mixed, the brightness is extremely changed between the two-dimensional display and the three-dimensional display, which is very troublesome and eye fatigue. Becomes fierce.

Therefore, in the fourth embodiment, a mechanism for providing a signal correction section 9c in the display monitor drive circuit 9 and adjusting the difference in brightness between two-dimensional display and three-dimensional display to be substantially equal. Was set up.

With such a structure, the two-dimensional display and the three-dimensional display are performed.
It is possible to eliminate the uncomfortable feeling that occurs when switching the three-dimensional display.

[0124] Also, after switching once, 2
A switch may be provided so as to manually switch so as not to perform signal correction in a case where dimensional display continues and if it is desired to observe a bright image.

[0125]

As described above, the liquid crystal display device according to the present invention can achieve the following operational effects. That is, a method of observing a stereoscopic image with polarizing glasses by providing a liquid crystal shutter on the front surface of the display monitor, or a method of observing a stereoscopic display by using a polarizing plate on the front surface of the display monitor, or a display monitor. In the method of displaying a left-eye image and a right-eye image on the same screen and observing a stereoscopic image by a parallax barrier provided in front of the image, (1) even if a liquid crystal panel is used as a monitor, Since the light utilization efficiency can be increased in total in terms of configuration and driving method, a bright image can be obtained without increasing power consumption.

(2) Even if a liquid crystal panel is used as a monitor, a high-speed response can be realized, and since an afterimage does not remain, a double image or flicker does not appear, and a feeling of fatigue inherent in stereoscopic vision is reduced. be able to.

(3) Since the field sequential color system uses a light source composed of LEDs of high color purity, stereoscopic display with good color reproducibility can be obtained.

From the above, it is possible to provide a stereoscopic display method and a stereoscopic display device which are space-saving and can observe a high-quality stereoscopic display without feeling tired. Therefore, the industrial value is extremely large. .

[Brief description of drawings]

FIG. 1 is an overall view showing a configuration of a stereoscopic display device according to a first embodiment of the present invention.

FIG. 2 is a plan view illustrating a configuration of a display unit according to the first embodiment of the present invention (a) a pixel configuration diagram including two types of pixels for a left eye and pixels for a right eye (b) a pixel including only one type Diagram

FIG. 3A is an enlarged cross-sectional view showing a configuration of a liquid crystal panel used for the stereoscopic display device according to the first embodiment of the present invention. FIG. 3B is a liquid crystal used for the stereoscopic display device according to the first embodiment of the present invention. Enlarged plan view of pixel section showing panel configuration

FIG. 4 is a timing chart of writing to liquid crystal, liquid crystal response, and backlight in the stereoscopic display method according to the first embodiment of the present invention.

FIG. 5 is an overall view showing a configuration of a stereoscopic display device according to a second embodiment of the present invention.

FIG. 6 is a plan view showing the principle of stereoscopic vision (parallax stereogram) according to the second embodiment of the present invention.

FIG. 7 is a plan view showing the principle of stereoscopic vision (parallax stereogram) according to the second embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of an input unit of a stereoscopic display device according to a third embodiment of the present invention.

FIG. 9 is a block diagram showing a configuration of an input unit of a stereoscopic display device according to a fourth embodiment of the present invention.

FIG. 10 is a diagram showing a configuration example of a stereoscopic image display device in a conventional example.

[Explanation of symbols]

1 stereoscopic display 2 Display monitor 3 Polarizer 4 LCD shutter 5 Phase plate 6 polarized glasses 7 Image signal 8 Image processing unit 9 Display monitor drive circuit 9a 2D display driver 9b 3D display driver 9c Signal correction unit 10 Synchronous circuit 11 Display monitor pixel section 11a Left eye pixel 11b Right eye pixel 12 LCD panel 13 Backlight 14 Array substrate 15 Counter substrate 16 Liquid crystal layer 17 Counter electrode 18 pixel electrodes 19 Video signal line 20 scanning signal lines 21 Semiconductor switch element 22 First insulating layer 23 Second insulating layer 24 Black matrix layer 25 Alignment film 26 LED light source 26a Red LED 26b green LED 26c blue LED 27 Reflector 28 Light guide plate 29 Spacer 30 Parallax Barrier 30a Light-shielding part for left-eye observation 30b Light-shielding part for right-eye observation 31 Observer 31a Left eye 31b right eye 32 Observer position detector 33 Data processing unit 34 Phase inversion control circuit 35 Switching unit

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G09G 3/20 611 G09G 3/20 611E 5C080 621 621A 641 641E 642 642D 642E 650 650B 660 660 3/34 34 J 3/36 3/36 F term (reference) 2H059 AA23 AA26 AA33 AA38 2H088 EA06 EA07 GA02 GA04 HA06 HA16 HA28 JA17 JA20 KA07 2H093 NA65 NC43 NC44 ND08 ND10 ND17 ND17 A22 A11A22 A11A22A11A14A16A16A17A14A16A16A20A16A17A14A16A16A16A16A16A16A16A16A16A16A16A16A16A16A16A16A16A16A16A16A16A16A22A16A16A16A22A16A16A22 AF27 AF44 AF51 AF53 AF73 BA12 BA13 BA15 BA16 BB12 BB16 BB28 BB29 BC03 BC11 BF24 EA01 EA03 EC12 FA04 FA05 FA12 FA16 FA23 FA24 FA25 FA34 FA47 FA54 FA55 FA56 5C061 AA03 AA11 AA14 AB12 AB14 AB16 AB17 5C08003A10 EE29 EE30 FF11 JJ02 JJ04 JJ06

Claims (36)

[Claims] 1. A display means for alternately assigning an image for the left eye and an image for the right eye for each field and displaying them on the same screen in time sequence, and for switching between the image for the left eye and the image for the right eye. A stereoscopic display method for observing a stereoscopic image by selectively viewing the image for the left eye on the left eye and the image for the right eye on the right eye in synchronization, wherein the display unit is an optical switching unit, and A light source for irradiating the light switching means and a driving means for time-sequentially switching the color of the light source and controlling the transmission state or the reflection state of the light switching means in synchronization with the light source are provided, and color display is performed by temporally additive color mixing A stereoscopic display method characterized by the above. 2. A display means for alternately assigning an image for the left eye and an image for the right eye for each field and displaying them on the same screen in time sequence, and for switching between the image for the left eye and the image for the right eye. A stereoscopic display device for observing a stereoscopic image by selectively viewing a left-eye image for the left eye and a right-eye image for the right eye in synchronization, wherein the display unit of the display means is for the left eye. A stereoscopic display device, comprising: a left-eye pixel portion for displaying an image and a right-eye pixel portion for displaying a right-eye image. 3. The display means comprises a liquid crystal panel, a light source for irradiating the liquid crystal panel, and a color of the light source, which is switched sequentially in time sequence, and in synchronization therewith, a driving means for controlling the transmission or reflection state of the liquid crystal panel. The three-dimensional display device according to claim 2, wherein the three-dimensional display device is a field sequential color system that performs color display with additive color mixture over time. 4. A display means for displaying an image for the left eye and an image for the right eye on the same screen, and a parallax barrier, wherein the left eye image is for the left eye and the right eye is for the right eye. A stereoscopic display method for observing a stereoscopic image by selectively viewing an eye image, wherein the display means includes an optical switching means, a light source for irradiating the optical switching means, and a color of the light source in time sequence. A stereoscopic display method comprising a driving means for switching and controlling a transmission state or a reflection state of the optical switching means in synchronism with the switching, and performing color display by additive color mixture over time. 5. A display means for displaying an image for the left eye and an image for the right eye on the same screen, and a parallax barrier, the left eye image for the left eye and the right eye for the right eye. A stereoscopic display device for observing a stereoscopic image by selectively viewing an eye image, wherein the display unit of the display unit includes a left eye pixel unit for displaying a left eye image, and a right eye image. A pixel unit for the right eye for displaying the liquid crystal panel, the display unit switches the color of the liquid crystal panel, a light source for irradiating the liquid crystal panel, and the light source in time sequence, and the liquid crystal panel in synchronization with it. A stereoscopic display device characterized by a field-sequential color system that includes a driving unit that controls the transmission or reflection state of the field, and that performs color display with an additive color mixture over time. 6. The parallax barrier is constituted by an optical switching means.
3D display device. 7. The stereoscopic display device according to claim 6, wherein the light switching means is a light scattering type liquid crystal element. 8. The stereoscopic display device according to claim 6, wherein the optical switching unit is an OCB mode liquid crystal in which a phase compensating plate is disposed in front of a bend alignment liquid crystal. 9. A standard display mode for displaying a normal two-dimensional image by displaying the same image on the image for the left eye and the image for the right eye, 2.
The stereoscopic display device according to any one of 3, 5 to 8. 10. The stereoscopic display according to claim 9, further comprising switching means for freely switching between a stereoscopic display mode for displaying the stereoscopic video and a standard display mode for displaying a normal two-dimensional image. apparatus. 11. The stereoscopic display device according to claim 10, wherein the display mode is automatically switched to one of the standard display mode and the stereoscopic display mode depending on the type of video signal. 12. Before and after switching the display mode,
The stereoscopic display device according to any one of claims 9 to 11, further comprising a correction unit configured such that the brightness of the display unit is substantially the same. 13. The stereoscopic display according to claim 2, wherein the display means is an OCB mode liquid crystal in which a phase compensating plate is arranged in front of a bend alignment liquid crystal. Display device. 14. The display means is a liquid crystal panel,
The three-dimensional display device according to any one of claims 2, 3, 5 to 12, wherein the liquid crystal layer is a ferroelectric liquid crystal. 15. The display means is a liquid crystal panel,
13. The stereoscopic display device according to claim 2, wherein the liquid crystal layer is an antiferroelectric liquid crystal. 16. The stereoscopic display device according to claim 13, wherein the liquid crystal layer has a retardation Δn · d (retardation) of 600 nm or more and 900 nm or less, and the liquid crystal layer is a cyano material. 17. The stereoscopic display device according to claim 16, wherein the content of the cyano material is 10% or less. 18. The stereoscopic display device according to claim 13, wherein the cyano material contains a PCH (phenyl cyclohexane) group. 19. The cyano-based material is a cyano-based material containing a terphenyl group.
The stereoscopic display device according to item 3. 20. The stereoscopic display device according to claim 13, wherein the liquid crystal layer has a thickness of 2.5 μm or more and 3.5 μm or less. 21. The refractive index anisotropy Δn of the liquid crystal layer is 0.
The stereoscopic display device according to claim 13, wherein the stereoscopic display device is 24 or more. 22. The viscosity coefficient η of the liquid crystal layer is 30 mPa.
The stereoscopic display device according to claim 13, wherein the stereoscopic display device has a value of s or more and 60 mPas or less. 23. A black voltage for applying a voltage for displaying black in the liquid crystal panel is inserted and driven at a constant rate in one frame, and the liquid crystal layer contains a PCH (phenyl cyclohexane) group. 14. The stereoscopic display device according to claim 13, which is a cyano material. 24. The stereoscopic display device according to claim 23, wherein the driving frequency is 300 Hz or less. 25. A black voltage for applying a voltage for displaying black in the liquid crystal panel is inserted at a constant rate in one frame and driven at a driving frequency of 360 Hz or higher, and the liquid crystal layer is a terphenyl group. 14. The stereoscopic display device according to claim 13, wherein the stereoscopic display device comprises a cyano material. 26. The stereoscopic display device according to claim 25, wherein the liquid crystal layer is made of a fluoro material. 27. The stereoscopic display device according to claim 25, wherein the liquid crystal layer is made of a fluorotolan material. 28. The light source used for the display means is LE
The stereoscopic display device according to any one of claims 2, 3, 5 to 27, which comprises a D element. 29. A method for forming one frame by the driving means performing a frame sequential process of four or more fields in which three fields of red, green, and blue, and fields of intermediate colors excluding the three primary colors are added. The stereoscopic display device according to any one of claims 2, 3, 5 to 28, wherein 30. The method according to claim 2, wherein the driving means is a method of forming one frame by performing frame sequential three fields of red, green, and blue twice.
The stereoscopic display device according to any one of 3, 5 to 28. 31. The stereoscopic display device according to claim 29, wherein the intermediate color is white. 32. The stereoscopic display device according to claim 29, wherein the intermediate color is any one of cyan, magenta, and yellow. 33. The stereoscopic display device according to claim 29, wherein the intermediate color is a combination of two or more of cyan, magenta, yellow, and white. 34. The intermediate color is a combination of any three of cyan, magenta, yellow, and white,
30. The stereoscopic display device according to claim 29, wherein the intermediate color fields are respectively inserted between the red, green, and blue color fields. 35. The stereoscopic display device according to claim 29, wherein a black field is inserted between the fields of the respective colors. 36. The stereoscopic display device according to claim 29, wherein black is written on the entire surface at once between the fields of the respective colors.