WO2005010593A1

WO2005010593A1 - Optical module for multiple view 3-dimensional image display, display apparatus and mthod using the same

Info

Publication number: WO2005010593A1
Application number: PCT/KR2003/001499
Authority: WO
Inventors: Eun-Soo Kim; Seung-Chul Kim; Young-Woon Park; Jung-Sik Koo
Original assignee: Maxsoft Co., Ltd
Priority date: 2003-07-25
Filing date: 2003-07-25
Publication date: 2005-02-03
Also published as: AU2003248148A1

Abstract

The present invention discloses an optical module for multiple view stereoscopic image display, a display device using the optical module and a method thereof. The optical module of the present invention comprises a PBS for passing P wave component of an input beam straight and reflecting S wave component of the input beam, the first and the second beam splitter for dividing beams from the PBS into more than two routes, and a plurality (preferably, four) of LCOS for reflecting beams from the first beam splitter or the second beam splitter and displaying each 2D image data with different viewpoint (preferably, four) respectively. The stereoscopic image display device comprises a screen, the optical module, and a projection lens for magnifying the output beams from the optical module and projecting the magnified beams onto the screen. According to the present invention, by projecting more than two viewpoints onto the screen, it is possible to display stereoscopic image more naturally and with presence feeling.

Description

Title of the invention

Optical module for multiple view 3 -dimensional image display, display

apparatus and method using the same

Field of the invention

The present invention relates to a stereoscopic(3D) image display, more

particularly, an optical module for projection-type multiple view stereoscopic image

display, a stereoscopic image display device using optical module and a method of

stereoscopic image display.

Background of the present invention

Since the stereoscopic(3D) image display technique can provide a presence

feeling, real feeling, natural feeling much more than 2D image display can do, this

technique is widely applicable to TV, broadcasting, medical, communication, movie,

game, etc.

Generally, human can see object stereoscopically by way of binocular disparity.

That is, left and right eye see different 2D images respectively, and when these two

images are delivered to brain through the retina, brain combines these two images to

reproduce the depth feeling and presence feeling of original 3D stereoscopic image. Up to now, stereoscopic(also called binocular parallax) method has been mainly used for 3D image display. The stereoscopic method uses 2-views of left-eye image and

right-eye image.

There are two types in stereoscopic method: spectacles type and non-spectacles

type. Examples of spectacles type method include: a discoloration method with color

spectacles of using different wavelengths of light, a polarization spectacles method of

using different oscillating directions of lights, and a liquid crystal shutter method of

seeing left and right images by time divisional way. Although the spectacles method can

provides relatively clear images, it also has some defects such as an inconvenience of

wearing spectacles and the limited scenographic effect to fixed viewing point. In order

to solve the defects of spectacles type method, non-spectacles method is proposed.

Non-spectacles method divides images corresponding to each left and right eye by use

of a parallax barrier, a lenticular sheet, a fly eye lens, etc., and displays the divided

images onto a certain viewing region.

On the other hand, a projection 3D image display system, as a device for

magnifying and projecting images on a large screen, is used variously because it can

enlarge the size of monitor. Of course, the stereoscopic method in projector also uses

aforementioned spectacles or non-spectacles method for displaying stereoscopic images.

But, there is still inconvenience in the stereoscopic method that the viewer has

to wear spectacles. Also, since the method uses two viewpoint images, it is not enough

to provide a natural stereoscopic effect, and it is impossible to provide same stereoscopic images to plural viewer at the same time.

In order to overcome the defects of aforementioned stereoscopic method and

display the natural stereoscopic images, many studies have being performed on

auto-stereoscopic method(also called complex parallax method) using multiple view

images more than 2 views.

Summary of the present invention

Thus, the object of the present invention is to provide a multiple view

stereoscopic image display device and method for a viewer to see natural stereoscopic

images without wearing spectacles.

To achieve aforementioned object, an optical module for stereoscopic image

display according to the preferred embodiment of the present invention, comprises a

PBS for passing P wave component of an input beam straight and reflecting S wave

component of the input beam, the first and the second beam splitter for dividing beams

from the PBS into more than two routes, and a plurality of LCOS for reflecting beams

from the first beam splitter or the second beam splitter, and displaying each 2D image

data with different viewpoint respectively. Preferably, the optical module further

comprises the first phase delaying waveplate for delaying the P wave component by the

first phase to be inputted into the first beam splitter, and the second phase delaying

waveplate, delaying the S wave component by the second phase to be inputted into the second beam splitter.

To achieve above object, a stereoscopic image display device according to the

preferred embodiment of the present invention comprises a screen, an optical module

for outputting beams carrying 2D image data of four views as a response to an input

beam from a light source, and a projection lens for magnifying the output beams from

the optical module and projecting the magnified beams onto the screen. Preferably, the

optical module comprises a PBS for passing P wave component of an input beam

straight and reflecting S wave component of the input beam, the first and the second

beam splitter for dividing beams from the PBS into more than two routes, the first phase

delaying waveplate for delaying the P wave component by the first phase to be inputted

into the first beam splitter, the second phase delaying waveplate for delaying the S wave

component by the second phase to be inputted into the second beam splitter, and the

first, the second, the third and the fourth LCOS for reflecting beams from the first beam

splitter or the second beam splitter and displaying each 2D image data of four

viewpoints respectively.

To achieve aforementioned object, the method for displaying stereoscopic

image according to the preferred embodiment of the present invention comprises the

steps of (a) separating an input beam into a P wave component and S wave component

to progress toward different directions, (b) dividing the P wave component into more

than two routes, (c) dividing the S wave component into more than two routes, and (d) displaying 2D image data with different viewpoints by reflecting the divided beams of

the (b) and (c) to LCOS respectively.

Brief description of drawings In order to fully appreciate the accompanying drawings being used in the

detailed description of the present invention, brief descriptions for each drawing are

now provided.

FIG. 1 illustrates a display mechanism of the liquid crystal on silicon(LCOS),

which is used in the optical module and stereoscopic image display device according to

the present invention;

FIG. 2a and FIG. 2b are a perspective view and a top view of the optical module

210 for multiple view stereoscopic image display according to the preferred

embodiment of the present invention;

FIG. 3a to FIG. 3d show beam routes of each view in the optical module 210

shown in FIG. 2a and FIG. 2b;

FIG. 4 illustrates the stereoscopic image display device according to the

preferred embodiment of the present invention;

FIG. 5 shows the stereoscopic image display device of FIG. 4 in detail,

especially, a rear-projection type stereoscopic image display device 500; FIG. 6 is a rear view, a sectional view, and a front view of the Fresnel screen. Detailed description of the present invention

In order to fully appreciate the present invention, its advantages and object to

be accomplished by the embodiment of the present invention, accompanying drawings

and description on each drawings, both indicating the preferred embodiment of the

present invention, must be referred.

Hereinafter, the present invention will be described with referring the

accompanying drawings. Same reference number throughout whole drawings will

indicate same part. FIG. 1 illustrates a display mechanism of the liquid crystal on silicon(LCOS),

the present invention.

FIG. 1 shows the basic concept that light generated by a light source(not shown)

is inputted to LCOS 130 and read 2D image data displayed on LCOS 130 in the form of

reflection, and can be described in detail as follows.

When unpolarized beams(SI, PI) of light incident to PBS(polarized beam

splitter) from a light source(not shown), P(perpendicular) wave component(PI) is

transmitted and S(standard)-wave component(SI) is reflected by 90 degrees at PBS.

When passing through λ 14 phase-delaying waveplate 120, the reflected SI is circularly

polarized. When being reflected by LCOS 130, the circular polarized beam(CI) reads 2D image data displayed on LCOS 130. The beam carrying 2D image data(CR) is

transformed into P wave component(PR) when passing through λ 14 phase-delaying

waveplate 120 again. PR goes straight through PBS 110. By projecting PR on screen,

2D image data carried by PR can be displayed. Similar to the fundamental of reading 2D image data by reflecting SI to LCOS

130, it is possible to read another 2D image data by reflecting PI to another LCOS(not

shown).

It is possible to realize an optical module for multiple view stereoscopic image

display based on LCOS and a multiple-view stereoscopic image display device with the

optical module by using the aforementioned polarization features of light and optical

elements(LCOS, PBS and phase delaying waveplate, etc). LCOS is a display device,

more particularly, which a glass of bottom plate of LCD element ϊs replaced by silicon

wafer and a circuit is formed thereon.

FIG. 2a and FIG. 2b are a perspective view and a top view of the optical module

210 for multiple view stereoscopic image display according to the preferred

embodiment of the present invention.

Referring to FIG. 2a and FIG. 2b, the optical module 210 for multiple view

stereoscopic image display comprises a PBS 211, two beam splitters 213a, 213b, two

λ 14 phase delaying waveplates 215a, 215b, and four LCOS 217a, 217b, 217c, 217d. The PBS 211 passes P wave component of incident beam and reflects S wave component. The λ 14 phase delaying waveplates 215a, 215b delay the phase of beams

from the PBS 211 by 1/4 of one wavelength of incident beam(λ 14 ). The beam splitters

213a, 213b splits beams from the λ 14 phase delaying waveplates 215a, 215b into more

than two. And, LCOS 217a-217d reflect each incident beam to display each 2D image

data recorded thereon. It is preferable that viewpoints of each 2D image data that LCOS

217a-217d display are different from each other. For example, the first LCOS 217a, the

second LCOS 217b, the third LCOS 217c and the fourth LCOS 217d display the first

view 2D image data, the second view 2D image data, the third view 2D image data and

the fourth view 2D image data, respectively. It is preferable that the beam splitters 213a,

213b are arranged perpendicular to each other with the PBS 211 as reference, and the

λ 14 phase delaying waveplates 215a, 215b are arranged between the PBS 211 and the

beam splitters 213a, 213b. And, it is preferable that LCOS 217a ~ 217d are color LCOS

for reflecting incident beam and displaying color image.

FIG. 3a to FIG. 3d show beam routes of each view in the optical module 210

shown in FIG. 2a and FIG. 2b.

At first, referring FIG. 3 a and FIG. 3b showing the first and the second view

beam route, when unpolarized beams(PI, SI) are passing through PBS 211, S wave

component(SI) is reflected by 90 degrees. The reflected SI is transformed into circular

polarized beam(CI) on passing through the λ 14 phase delaying waveplate 215a. The

circular-polarized CI is divided into two beams CIl, CI2 at the beam splitter 213a. CIl, one of the divided beams, is reflected by the first LCOS 217a and read the first view 2D

image data of the first LCOS 217a. Since the first LCOS 217a is tilted at θ 1 in vertical

direction, the reflected beam CR1 carrying the first view 2D image data comes out of

beam splitter 213a with an angle different from that of CIl. Namely, the first LCOS

217a is arranged for the incident angle of CIl to be a certain angle, not 90 degrees. CR1

is transformed into P polarized beam(PRl) when passing through the λ 14 phase

delaying waveplate 215a and goes straight through PBS 211. CI2, the other beam of the

divided beams, is reflected by the second LCOS 217b and reads the second view 2D

image data of the second LCOS 217b. When passing through the beam splitter 213a and

the λ 14 phase delaying waveplate 215a, CR2 carrying the second view 2D image data

is transformed into P polarized beam(PR2) and goes straight through PBS 211.

Referring FIG. 3c and FIG. 3d showing the third and the fourth view beam route,

P wave component(PI) of the unpolarized beams(PI, SI) goes straight through PBS 211.

The straight PI is transformed into circular-polarized beam(CF) when passing through

the λ 14 phase delaying waveplate 215b. CF is divided into two beams(CI3, CI4) by

the beam splitter 213b. CI3, one of the divided beams is reflected by the third LCOS

217c and reads the third view 2D image data of the third LCOS 217c. Since the first

LCOS 217a is tilted at θ 3 in vertical direction, CR3 carrying the third view 2D image

data comes out of beam splitter 213b with an angle different from that of CI3. CR3 is

transformed into S polarized beam(SR3) when passing through the λ 14 phase delaying waveplate 215a and is reflected by PBS 211. CI4, the other beam of the divided beams,

is reflected by the fourth LCOS 217d and reads the fourth view 2D image data of the

fourth LCOS 217d. When passing through the beam splitter 213b and the λ 14 phase

delaying waveplate 215b, CR4 carrying the second view 2D image data is transformed

into S polarized beam(SR4) and is reflected by the PBS 211.

It is preferable that each LCOS 217a-217d is tilted at a certain degrees in

vertical or horizontal direction. In the preferred embodiment, LCOS 217a and 217d are

tilted at the first angle(θ 1) and the fourth angle(θ 4) in vertical direction, and LCOS

217b and 217c are tilted at the second angle(θ 2) and the third angle(θ 3) in horizontal

direction. Namely, it is preferable to arrange each LCOS 217a-217d so that incident

angle of one beam entering into itself are different from the incident angle of another

beam entering into another LCOS. By this, view points of each beam(PRl, PR2, SR3,

SR4) being reflected by each LCOS 217a-217d are different from each other. As a result,

the viewing zones are separated. Output beams(PRl, PR2, SR3, SR4) enter into the

projection lens that will be described later.

FIG. 4 illustrates the stereoscopic image display device according to the

preferred embodiment of the present invention. Referring to FIG. 4, the stereoscopic

image display device according to the present invention comprises an optical module

210, a projection lens 220 and a screen 230. Since the optical module has been already

described with reference of FIG. 2 and FIG. 3, detailed description will be omitted here. Four beams outputted from the optical module 210 are projected onto the

screen 230 through the projection lens 220. The projection lens 220 magnifies the

beams outputted from the optical module 210. Preferably, the screen 230 is Fresnel

screen. Structure of Fresnel screen will be described with reference of FIG. 5 and FIG. 6.

Since the view points of four beams outputted from the optical module 210 are

separated, the incident angles of each beam are different from each other when entering

the projection lens 220. Thus, since the refraction angles are different, the positions

V1~V4 on the Fresnel screen where each beams is focused on are also different.

FIG. 5 shows the stereoscopic image display device of FIG. 4 in detail,

especially, a rear-projection type stereoscopic image display device 500.

Referring to FIG. 5, rear-projection type stereoscopic image display device 500

comprises the optical module 210, the projection lens 220 and the Fresnel screen 230,

all shown in FIG. 4 and further comprises a light source 240 and mirrors 250, 260.

The light source 240 generates a beam to be inputted to the optical module 210.

The mirror 250 is disposed between the optical module 210 and the projection lens 220,

and reflects the output beam from the optical module 210. The mirror 260 is disposed

between the projection lens 220 and the Fresnel screen 230 and reflects the beam from

the projection lens 220 to the Fresnel screen 230.

The Fresnel screen 230, as shown at the enlarged part of FIG. 5, comprises a

Fresnel lens 231 , a lenticular sheet 232 and a diffusion plate 233. FIG.6 (a) is a rear view of the Fresnel screen 230, that is, when seeing toward

the Fresnel lens 231, FIG. 6 (b) is a sectional view of the Fresnel screen 230, and FIG. 6

(c) is a front view of the Fresnel screen 230, that is, when seeing toward the lenticular

sheet 232. The Fresnel lens 231 separates beams having different incident angles into

regions corresponding to each viewpoint(Nl-V4 of FIG. 4), and the lenticular sheet 232

being arranged in horizontal direction enlarges the top and bottom viewing angle of

output images. And the diffusion plate 233 eliminates dark zone that may occur at

between each viewpoint(Vl~N4 of FIG. 4). At this time, it is preferable to control the

density of diffuser in order to avoid the overlap of images corresponding to each

viewpoint(Vl-V4 of FIG. 4). Lights being focused on different spatial positions(Vl-N4

of FIG. 4) form three different viewing zones that cause the stereoscopic feeling, and the

viewer can feel 3D feeling within a certain region due to the binocular parallax.

Although the present invention is described with embodiment shown in

accompanying drawings, however, this is an exemplary only and those who skilled in

the art can appreciate that various changes and modification will be made without

departing from the spirit and scope of the present invention. Thus, the true scope of the

present invention must be determined by the spirits of attached claims. Industrial applicability

According to the present invention, through projection of multiple view images,

more than two images, on the screen by use of reflection-type LCOS, it is possible to

display stereoscopic image more naturally and with presence feeling. Also, according to

the present invention, it is possible to form plural viewing zones different from each

other so that many viewers can see stereoscopic images at the same time.

Claims

1. An optical module for stereoscopic image display, comprising: a PBS(polarized beam splitter), passing P wave component of an input beam

straight and reflecting S wave component of the input beam; a first and a second beam splitter, dividing beams from said PBS into more than

two routes; and a plurality of LCOS(liquid crystal on silicon), reflecting beams from said first

beam splitter or said second beam splitter, and displaying each 2D image data with

different viewpoint respectively.

2. The optical module of claim 1, wherein said optical module further

comprises: a first phase delaying waveplate, delaying the P wave component by a first

phase to be inputted into said first beam splitter; and a second phase delaying waveplate, delaying the S wave component by a

second phase to be inputted into said second beam splitter.

3. The optical module of claim 2, wherein the first phase and the second phase

are 1/4 wavelength of the input beam.

4. The optical module of claim 2, wherein said plurality of LCOS comprises: a first and a second LCOS, reflecting more than two beams from said first beam

slitter respectively; and a third and a fourth LCOS, reflecting more than two beams from said second

beam slitter respectively.

5. The optical module of claim 4, wherein said first, said second, said third and

said fourth LCOS display a first, a second, a third and a fourth 2D image data.

6. The optical module of claim 4, wherein said first, said second, said third and

said fourth LCOS are arranged so that incident angles of each incident beam are

different from each other.

7. The optical module of claim 6, wherein said first beam splitter and said

second beam splitter are arranged perpendicular to each other with said PBS as

reference, said first phase delaying waveplate is arranged between said PBS and said

first beam splitter, and said second phase delaying waveplaet is arranged between said

PBS and said second beam splitter.

8. The optical module of claim 4, wherein said first, said second, said third and said fourth LCOS are reflection-type color LCOS.

9. A stereoscopic image display device, comprising: a screen; an optical module, outputting beams carrying 2D image data of four views as a

response to an input beam from a light source; and a projection lens, magnifying the output beams from said optical module and

projecting the magnified beams onto said screen.

10. The stereoscopic image device of claim 9, wherein said optical module

comprises: a PBS, passing P wave component of an input beam straight and reflecting S

wave component of the input beam; a first and a second beam splitter, dividing beams from said PBS into more than

two routes; a first phase delaying waveplate, delaying the P wave component by a first

phase to be inputted into said first beam splitter; a second phase delaying waveplate, delaying the S wave component by a

second phase to be inputted into said second beam splitter; and a first, a second, a third and a fourth LCOS, reflecting beams from said first beam splitter or said second beam splitter, and displaying each 2D image data of four

viewpoints respectively.

11. The stereoscopic image device of claim 10, wherein said first and said

second phase are 1/4 wavelength of the input beam.

12. The stereoscopic image device of claim 10, wherein said first, said second,

said third and said fourth LCOS are arranged so that incident angles of each incident

beam are different from each other.

13. The stereoscopic image device of claim 10, wherein said first, said second,

said third and said fourth LCOS are reflection-type color LCOS.

14. The stereoscopic image device of claim 9, wherein said screen comprises: a Frenel lens; a lenticular sheet; and a diffusion plate, locating between said Frenel lens and said lenticular sheet.

15. A method for displaying stereoscopic image, comprising: (a) separating an input beam into a P wave component and S wave component to progress toward different directions;

(b) dividing the P wave component into more than two routes;

(c) dividing the S wave component into more than two routes; and

(d) displaying 2D image data with different viewpoints by reflecting the divided

beams of said (b) and (c) to LCOS respectively.

16. The method for displaying stereoscopic image, wherein said (d) uses four

LCOS.