WO2016186434A1

WO2016186434A1 - Stereoscopic image device for reducing cross-talk

Info

Publication number: WO2016186434A1
Application number: PCT/KR2016/005224
Authority: WO
Inventors: 이영훈; 이철우
Original assignee: 유한회사 마스터이미지쓰리디아시아
Priority date: 2015-05-18
Filing date: 2016-05-18
Publication date: 2016-11-24
Also published as: KR101675436B1

Abstract

The present invention presents a stereoscopic image device comprising: a first polarizing beam splitter (PBS) for spatially splitting image light emitted from a projector into one or more transmitted light beams and one or more reflected light beams according to polarization components, and emitting the split image light; a first modulator performing modulation so as to have circularly polarized light beams different from each other, according to the alternate emitting, to a left image and a right image, of transmitted light in a time-division manner, such that the transmitted light beams are emitted at a screen; a second modulator performing modulation so as to have circularly polarized light beams different from each other, according to the alternately emitting, to a left image and a right image, of reflected light in a time-division manner, such that the reflected light beams are emitted at a screen; and a second PBS arranged between the second modulator and 3D glasses so as to block light having a specific polarization component, which is not converted into circularly polarized light by the second modulator.

Description

Stereoscopic image device to reduce crosstalk

The following description relates to a stereoscopic imaging apparatus which effectively reduces crosstalk in a stereoscopic imaging apparatus using a polarized light splitter.

In general, a method of implementing a stereoscopic image (or 3D image) is realized by illuminating different images on two human eyes, and in the case of a stereoscopic image displayed on a large screen such as a theater, polarization in a direction in which the left and right sides are perpendicular to each other Through polarizing glasses having a lens, a polarization method for distinguishing and transmitting a left image and a right image is mainly used. This takes images using two cameras, displays the two images on one screen by overlapping images having right angle deviations using polarization means, and images taken by the two cameras through the polarizing glasses described above. The three-dimensional image is implemented by viewing the left and right eyes respectively.

1 is a view showing the structure of a conventional two-projector system for displaying a stereoscopic image.

In order to perform stereoscopic image display by the polarization method as described above, in the conventional two projector system, the left image is irradiated on one projector 1 by two conventional two-dimensional (2D)

projectors

1 and 2, The other projector 2 allows the right image to be irradiated so that each of these images is irradiated onto the screen 5 by passing through the polarization filters 3 and 4 whose polarization directions are perpendicular to each other. The left image and the right image, which are irradiated on the screen 5, overlap the left and right sides of the viewer through each of the left image lens 7 and the right image lens 8 of the polarizing glasses 6 worn by the viewer. It is a way of making three-dimensional impressions by looking inside.

In the above-described method, it is possible to apply different polarizations to the left image and the right image by both linear polarization and circular polarization.

Such a conventional two-projector stereoscopic image screening system has been replaced by the following one-projector system in which the projector alternately irradiates the left and right images in time.

2 is a view for explaining a 1 projector circular polarization filter system.

As shown in FIG. 2, the three-dimensional image projector system includes a single projector 201 sequentially irradiating a left image and a right image, a circular polarization filter unit 202 including a polarization filter for a left image and a polarization filter for a right image. And a filter driver 203 which rotates and drives the circularly polarized filter unit 202 described above to synchronize timing of left image irradiation and right image irradiation of the projector 201. In addition, as shown in FIG. 2, the synchronization unit 204 may further include a synchronization unit 204 for acquiring timing synchronization of the left image irradiation and the right image irradiation of the projector 201 and transmitting the timing synchronization to the filter driver 203 described above.

The projector 201 continuously receives the contents for the stereoscopic images in which the left image and the right image are stored in order, and continuously examines the contents. The circular polarization filter unit 202 includes a polarizing film for the left image and a polarizing film for the right image as described above, and at the timing when the projector 201 irradiates the left image through rotation, the polarizing filter for the left image of the projector When the projector 201 is irradiated to the right image, the polarizing filter for the right image is adjusted to be positioned at the irradiation port of the projector 201.

However, in the one projector method as described above, the brightness decreases as the image light emitted from one projector is divided into left and right images.

In order to solve the brightness reduction problem of the conventional one-projector system as described above, a stereoscopic image display apparatus in which the transmitted light and the reflected light are collected on the screen by using a polarized light splitter and improved in brightness is introduced. Specifically, the three-dimensional image light, which is sequentially irradiated with the left image and the right image from the projector, is divided into at least one transmitted light and at least one reflected light according to the polarization component by using a polarized light splitter, and then the left image / right for each transmitted light / reflected light. A method of modulating a modulator to have different polarization directions according to an image irradiation point and then superimposing them on a screen has been introduced.

However, in the apparatus as described above, the use of a 1/2 wavelength retarder is essentially required to match the reflected light with the light transmitted by the polarization splitter (PBS) that divides the incident light according to the polarization component. This caused various problems.

The present invention proposes a system that does not use a half-wave retarder to solve the above problems, but specifically a stereoscopic image that effectively reduces crosstalk that may be a problem when the half-wave retarder is not used. An apparatus is proposed.

According to an aspect of the present invention for solving the above problems, a first polarized light splitter (PBS) for spatially dividing the image light irradiated from the projector into one or more transmitted light and one or more reflected light according to the polarization component; A first modulator configured to perform modulation on the circularly polarized light so that the transmitted light is irradiated to the left image or the right image in a time-divisional manner so that the transmitted light is irradiated onto the screen; A second modulator for modulating the reflected light to alternately polarize the reflected light to the left image or the right image so that the reflected light is irradiated onto the screen; And a second interposed between at least one of the first modulator and the second modulator (preferably a second modulator) and 3D glasses to block light of a particular polarization component that is not converted into circularly polarized light by the second modulator. A stereoscopic imaging apparatus including a PBS is proposed. In the above embodiment, the second PBS is preferably disposed between the second modulator and the 3D glasses, more specifically between the second modulator and the screen.

Specifically, the specific polarization component blocked by the second PBS may be a linear polarization component transmitted by the 3D glasses.

Here, either one of the left eye lens and the right eye lens of the 3D glasses blocks the light at the first time point, and the other one of the left eye lens and the right eye lens of the 3D glasses may block the light at the second time point. Can be.

In the above-described stereoscopic apparatus, the left eye lens and the right eye lens of the 3D glasses may be configured to transmit light in a first linearly polarized light direction and block light in a second linearly polarized light direction, and to enter the second modulator. The light may have the first linear polarization direction.

That is, the stereoscopic image device preferably does not include a 1/2 wavelength phase retarder in front of the first modulator and the second modulator. Since it does not include the 1/2 wavelength phase retarder as described above, the first modulator and the first linear polarization component of the light incident on the first modulator and the second linear polarization component of the light incident on the second modulator are perpendicular to each other. The light output by the second modulator may be configured to have the same circular polarization direction at the same time.

The first modulator and the second modulator may include a quarter wavelength phase delay unit.

In addition, the second PBS may have any one or more of a film form, a coating form and a liquid crystal form.

Meanwhile, a clean-up polarizer may be further included between the first PBS and the second modulator or inside the second modulator in front of the liquid crystal LC. Here, the specific linearly polarized light selectively transmitted by the clean-up polarizer may be blocked by the second PBS. That is, the second PBS is preferably configured to block circularly polarized light that is not converted into circularly polarized light so that circularly polarized light is transmitted.

According to the embodiments of the present invention as described above, it is possible to provide a high quality image quality with excellent color characteristics by using a polarizer without using a conventional 1/2 wavelength phase retarder, Even if not used, crosstalk can be efficiently reduced to display high quality stereoscopic images.

2 is a view for explaining a 1 projector circular polarization filter system.

3 is a view for explaining an example of a stereoscopic image display apparatus using a polarized light splitter to which the present invention can be applied.

4 is a view showing another example for explaining a stereoscopic image display apparatus using a polarized light splitter to which the present invention can be applied.

FIG. 5 is a diagram for describing a relationship with 3D glasses in a stereoscopic imaging apparatus using PBS as shown in FIGS. 3 and 4.

FIG. 6 is a view for explaining an operation when omitting a 1/2 phase delay unit and crosstalk increase according to an embodiment of the present invention.

7 and 8 are views for explaining a stereoscopic image device for reducing crosstalk according to an embodiment of the present invention.

9 and 10 are diagrams for further explaining a crosstalk reduction method when a 1/2 wavelength phase retarder is not used, according to an embodiment of the present invention.

FIG. 11 is a diagram showing a specific configuration to which an additional PBS for crosstalk reduction is applied according to one preferred embodiment of the present invention. FIG.

12 is a view for explaining a specific configuration of the LC for transmitted light and the LC for reflected light as a modulator configuration according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is intended to explain exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced.

The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, one of ordinary skill in the art appreciates that the present invention may be practiced without these specific details. In some instances, well-known structures and devices are omitted or shown in block diagram form, centering on the core functions of each structure and device, in order to avoid obscuring the concepts of the present invention.

In the stereoscopic image display apparatus shown in FIG. 3, the light emitted from the projector 302 is processed into two paths using a polarizing beam splitter (PBS) 301, and then processed again. ) To improve brightness.

In detail, the image light emitted from the projector 302 is divided into light having two polarization components in the polarization light splitter 301. That is, light having S-polarized light and P-polarized light component is reflected or transmitted by the PBS 301. The light having the transmitted P-polarization component is magnified by the lens 304 to form an image on the screen 303. On the other hand, the reflected S-polarized light is reflected by the reflector 305 to reach the screen 303. The above two transmitted / reflected lights are converted into the same linearly or circularly polarized light by the

modulators

306 and 307.

Meanwhile, since the two transmitted / reflected light have different polarization components, it is required to convert them to the same polarization. In one example of a system for this purpose, a half wave plate 308 is used for the reflected light path passing through the modulator 307, and a half wave plate is not used for the transmitted light path passing through the modulator 306. In other words, the image light of both optical paths has the same linear polarization (eg, P-polarization) at the front of the

modulators

306 and 307, and after passing through the

modulators

306 and 307, both are circularly polarized or in the same direction. As a result, they all had linearly polarized light in the same direction.

On the contrary, the half-wave plate is not used for the reflected light path passing through the modulator 307, and the half-wave plate 309 is used for the transmitted light path passing through the modulator 306. The front end of 306, 307 may all have S-polarized light, and after passing through the

modulators

306, 307, they may all have circular polarized light in the same direction or, in some cases, linearly polarized light in the same direction.

4 is a view showing another example for explaining a stereoscopic image display apparatus using a polarized light splitter to which the present invention can be applied. Specifically, the stereoscopic apparatus shown in FIG. 4 relates to a triple light system in which image light is divided into three by a polarized light splitter and processed.

In FIG. 4, the image light irradiated by the projector 401 is reflected by the first image light, the polarized light splitter 402, which passes through the

polarized light splitters

402 and 403, and is reflected by the reflective member 404. The second image light may be split into a third image light that is reflected by the polarized light splitter 403 and is reflected by the reflective member 405. In this case, the transmitted light and the reflected light are divided into one image light according to the polarization component, the two reflected light is characterized by dividing one image light into two. In this system, the two reflected light beams are preferably combined into one image on the screen.

In the embodiment of FIG. 4, the

polarized light splitters

402 and 403 are bent as shown, and the light passing through the center portion is refracted to prevent the loss due to incident on the connection part of the

polarized light splitters

402 and 403. It is shown to include

members

406 and 407.

Meanwhile, the

polarized light splitters

402 and 403 of FIG. 4 may be implemented in a prism form in consideration of optical path differences between transmitted light and reflected light, and various other methods may be used.

The time-division stereoscopic image emitted from the projector 510 may be modulated by the modulator 520 such that the left image and the right image have different circular polarization directions. In the case of the apparatus using the PBS as described above with reference to FIGS. 3 and 4, the stereoscopic image irradiated from the projector may be divided into transmitted light paths and reflected light paths and then modulated into circularly polarized light by the modulator 520. .

Light modulated by the modulator 520 is irradiated to the screen 530, and the light reflected by the screen 530 is incident on the 3D glasses 540.

As described above, when the circularly polarized light is used, the 3D glasses 540 generally include a λ / 4 phase delay unit and a linear polarizer, and the circularly polarized light reflected by the screen 530 and incident on the 3D glasses is 3D. It is converted into linearly polarized light in a specific direction by the λ / 4 phase delay of the glasses, and either one of the left eye lens or the right eye lens of the 3D glasses blocks the light at a specific point of time by the linear polarizing plate of the 3D glasses. It may be configured to transmit light.

For example, the right eye lens of the 3D glasses may transmit light at the first time point at which the right image is irradiated, and the left eye lens may block light. The left eye lens may be configured to transmit light, and the right eye lens may be configured to block the light.

Generally, 3D glasses have a film that blocks P-polarized light, and such a film may correspond to the linear polarizing plate described above.

FIG. 6 is a view for explaining an operation when omitting a 1/2 wavelength phase retarder and an increase in crosstalk according to an embodiment of the present invention.

FIG. 6 may be considered to specifically illustrate one side of the reflected light path when the P-polarized light is transmitted and the S-polarized light is reflected by the PBS 301 of FIG. 3 or the

PBSs

402 and 403 of FIG. 4. .

Specifically, FIG. 6 illustrates a case where S-polarized light is incident on the λ / 4 phase retarder or a modulator 610 serving as the same in the exemplary reflection optical path as described above. In general, the efficiency of converting linearly polarized light into circularly polarized light is known to be about 90%. Thus, for example, 90% of the light transmitted through the λ / 4 phase retarder 610 is converted into circularly polarized light, while the remaining 10% is unconverted and can maintain S-polarized light.

The 3D glasses basically include a λ / 4 phase retarder 620 and a linear polarizer 630 as described above, which linearly polarizes the S-polarized light and blocks the P-polarized light. Have

The 3D glasses illustrated in FIG. 6 illustrate a case where one lens of the 3D glasses should block light at a specific time point. That is, the left eye lens may correspond to the right eye lens when the left image is irradiated or the left eye lens when the right image is irradiated.

In this situation, the circularly polarized light is changed to P-polarized light by the λ / 4 phase retarder 620 of the 3D glasses, and thus can be blocked by the linear polarizer 630. Meanwhile, 10% of S-polarized light is again converted to S-polarized light after 1% corresponding to 10% of 10% passes through the λ / 4 phase retarder 620 of the 3D glasses with a similar conversion efficiency. 9% of the light corresponds to 90% of the S-polarized light and 9% of the light corresponds to 10% of the 90% circularly polarized light with circular polarization and the λ / 4 phase retarder of the 3D glasses. 620 (i.e., a total of 18% of the circularly polarized light passes through the λ / 4 phase retarder 620 of the 3D glasses).

Thus, 9%, which is half of unmodulated 1% S-polarized light and 18% circularly polarized light, passes through the linear polarizing plate 630 of the 3D glasses at that time. This causes 10% of the left and right images to pass through, resulting in cross-talk, which reduces the distinction between the left and right images of the stereoscopic image. In practice, the generally acceptable amount of crosstalk is less than about 2.5%.

3 and 4, if the light passes through the 1/2 lambda phase retarder before entering the modulator 610, the light incident on the modulator 610 becomes P-polarized light, and thus, as described above, P-polarized light, which is a linearly polarized component that is not converted by the 4-phase retarder 610, may be blocked by the 3D glasses so that the problem described above does not occur. However, as in the present invention, a 1/2 wavelength phase retarder is used. If not, crosstalk problems will occur as described above.

That is, when the half-wavelength phase retarder is not used at the front of the modulator 610 as in the present embodiment, the left eye lens and the right eye lens of the 3D glasses have the first linear polarization direction (for example, S-polarized light). Is configured to transmit light of the light beam and block light in the second linearly polarized light direction (eg, P-polarized light), the light incident on the modulator 610 of the reflected optical path is the first linearly polarized light direction (eg, S Polarization), and crosstalk as described above may be problematic.

7 and 6, the stereoscopic imaging apparatus according to the preferred embodiment of the present invention further includes a PBS 720 configured to block linearly polarized light in a specific direction. When the PBS 720 is used in FIGS. 7 and 8, it may be referred to as a second PBS to distinguish it from the PBS described with reference to FIGS. 3 and 4.

On the other hand, as a configuration for preventing crosstalk according to an embodiment of the present invention to block a specific linearly polarized component (ie, S-polarized component) by adding a general linearly polarized device at the position of the second PBS 720 described above. Although it may be considered, this may have the following problems.

If the light is modulated to left-circular polarization or right-circular polarization depending on the time point by the modulator 710 having a quarter-wave delay function, it passes through the linear polarizer disposed at the position of the second PBS 720. In this case, there is a problem that circularly polarized light is blocked by it and transmits only a specific linearly polarized light component. Therefore, in the above-described embodiment, the configuration for blocking the crosstalk is limited to the second PBS 720, and the method of reducing the crosstalk by arranging the linearly polarized light device at the corresponding position is a method of finally irradiating the screen with the linearly polarized light. It may be used only.

On the other hand, when the half-wavelength phase retarder is not used in front of the modulator 710 as described above with reference to FIG. 7, the light incident on the modulator 710 is not linearly blocked by the 3D glasses. For example, S-polarized light). As described above with respect to FIG. 6, the same is true that 10% of the light may remain as S-polarized light as it is transmitted through the quarter-wave phase retarder or LC modulator 710, but is additional in this embodiment. The PBS 720 is thus configured to block light that is not converted by the modulator 710 and is maintained as linearly polarized light, thereby reducing crosstalk as described above.

Specifically, PBS 720 may be configured to block all or some of the S-polarized light, and FIG. 7 illustrates a case where PBS 720 blocks all of the S-polarized light. As a result, the crosstalk level in the 3D glasses can be reduced to 2.25% or less.

As shown in FIG. 8, the PBS 720 according to the present embodiment is preferably disposed between the modulator 710 and the 3D glasses in the reflected optical path. 8 illustrates that the PBS 720 is added between the modulator 710 and the screen 860 of the reflected optical path, but the present invention is not limited thereto.

On the other hand, the PBS 720 described above may use not only a film form, but also various types of Polarization Beam Splitter (PBS), for example, coated PBS.

FIG. 9 illustrates a form in which S-polarized light, which is the polarization direction of the light of the reflected light path, of the light separated by triple light by PBS is converted into P-polarized light using a 1/2 wavelength phase retarder, and then modulated into circularly polarized light by a modulator. have. As described above, when the 1/2 wavelength phase retarder is used, the S-polarized light, which is a main factor for generating crosstalk, is effectively blocked as described above, but this may cause an increase in cost and a decrease in luminance.

FIG. 10 illustrates a case where transmitted light and reflected light are configured to have the same circular polarization direction after the modulator without using a 1/2 wavelength phase retarder to solve such a problem, such as asymmetric driving of the modulator or a modulator applied voltage. Doing. In addition, in the embodiment of FIG. 10, unlike the embodiments described above, a configuration is disposed after the modulator and at the front of the screen to block cross-polarization components (S-polarized light) that are not modulated with circular polarization by the modulator to improve crosstalk. Shows an example in which is specified as the second PBS.

The configuration for reducing crosstalk according to the present invention may include both the above-described linear polarizer and the second PBS, but it may be preferable to configure the PBS in the form of PBS to maintain the circularly polarized light component of the light. As described above, the use of the linear polarization device may be limited to the case where the linear polarization device is coupled while maintaining the linear polarization state on the screen.

The incident light incident through the window passes through the substrate 1120 before entering the first PBS 1120, thereby preventing light loss or distortion caused by the central portion of the PBS 1120. The first PBS 1110 preferably has a prism shape as shown in FIG. 11, but is not limited thereto. Light transmitted through the first PBS 1110 may enter the transmitted light LC 1140-1 with a specific linear polarization component (eg, P polarization component), and is reflected by the first PBS 1110. Silver may be incident on the reflected light LCs 1140-2 and 1140-3 with the linearly polarized light component reflected by the mirror elements 1130-1 and 1130-2 and orthogonal to the transmitted light.

As shown in the upper part of FIG. 12, the LC for transmitted light preferably has antireflective coatings at both ends. In addition, the LC for transmitted light may include a clean-up polarizer for removing unintended polarized light after the antireflective coating in the incident light path. The P-polarized light that has passed through such a clean-up polarizer may be modulated by the LCD 1 and the LCD 2 into left-circular polarization or right-circular polarization in synchronization with the image signal.

Meanwhile, as shown at the bottom of FIG. 12, the reflective LC may include an anti-reflection coding in the same manner as the LC for the transmitted light, and the incident light passing through the reflective light may pass through the clean-up polarizer to remove the unintended polarized light. The S-polarized light passing through the clean-up polarizer may be modulated into left-circular polarization or right-circular polarization in accordance with the synchronization of the image signal by LCD 1 and LCD 2, and the linear polarization direction input to the LCDs is determined by the transmitted light path. Although it is orthogonal to the light, it is preferable to modulate the output light to have the same circular polarization direction at the same time point as the light of the transmitted light path.

Referring back to FIG. 11, the light of the reflected optical path of the light subjected to such modulation is not converted into circularly polarized light by the aforementioned LC for reflection light by the second PBSs 1150-1 and 1150-2, and thus S-polarized light is converted. It blocks the light to be maintained. As shown in FIG. 11, the second PBSs 1150-1 and 1150-2 may be disposed at the rear ends of the LC LCs 1140-2 and 1140-3 in an inclined form with respect to the traveling direction of the reflected light path. .

In the above-described embodiment, the second PBSs 1150-1 and 1150-2 are for removing linearly polarized light that is not modulated into circularly polarized light by the modulator as compared to a clean-up polarizer disposed in front of the modulator or inside the modulator. It is distinguished from a clean-up polarizer for constituting the intended linear polarization direction prior to incidence. In addition, while the clean-up polarizer of the reflected light LC positioned in the reflected light path is configured to remove light other than S polarized light, the second PBSs 1150-1 and 1150-2 block S polarized light that is not converted into circularly polarized light. And the circular polarization of the remaining light as it is.

The detailed description of the preferred embodiments of the invention disclosed as described above is provided to enable any person skilled in the art to make and practice the invention. Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will understand that the present invention can be variously modified and changed from the above description.

As described above, the present invention can be widely used in homes, offices, and the like, as well as theaters requiring high quality stereoscopic image display by improving color quality and crosstalk performance with high brightness.

Claims

A first polarized light splitter (PBS) for spatially dividing the image light emitted from the projector into at least one transmitted light and at least one reflected light according to a polarization component;

A first modulator configured to perform modulation on the circularly polarized light so that the transmitted light is irradiated to the left image or the right image in a time-divisional manner so that the transmitted light is irradiated onto the screen;

A second modulator for modulating the reflected light to alternately polarize the reflected light to the left image or the right image so that the reflected light is irradiated onto the screen; And

And a second PBS disposed between the second modulator and the 3D glasses to block light of a specific polarization component that is not converted into circularly polarized light by the second modulator.
The method of claim 1,

The specific polarization component blocked by the second PBS is a linearly polarized light component transmitted by the 3D glasses.
The method of claim 1,

One of the left eye lens and the right eye lens of the 3D glasses blocks the light at the first time point,

The other one of the left eye lens and the right eye lens of the 3D glasses block the light at the second time point, the stereoscopic imaging device.
The method of claim 1,

The left eye lens and the right eye lens of the 3D glasses are configured to transmit light in the first linearly polarized direction and block light in the second linearly polarized direction,

The light incident on the second modulator has the first linear polarization direction.
The method of claim 1,

The stereoscopic imaging device does not include a 1/2 wavelength phase retarder in front of the first modulator and the second modulator.
The method of claim 1,

A first linearly polarized component of the light incident on the first modulator and a second linearly polarized component of the light incident on the second modulator are perpendicular to each other,

And the light output by the first modulator and the second modulator have the same circular polarization direction at the same time point.
The method of claim 1,

And the first modulator and the second modulator comprise a quarter wavelength phase delay unit.
The method of claim 1,

The second PBS has one or more of a film form, a coating form and a liquid crystal form, stereoscopic apparatus.
The method of claim 1,

And a clean-up polarizer in front of the liquid crystal (LC) between the first PBS and the second modulator or inside the second modulator.
The method of claim 9,

Specific linearly polarized light selectively transmitted by the clean-up polarizer is blocked by the second PBS.
The method of claim 1,

The second PBS is configured to block light of a specific polarization component that is not converted into circularly polarized light so that circularly polarized light is transmitted.