U.S. patent application number 14/789051 was filed with the patent office on 2015-10-22 for light source module for stereoscopic display, imaging device for stereoscopic display and stereoscopic display system.
This patent application is currently assigned to HISENSE HIVIEW TECH. CO., LTD.. The applicant listed for this patent is HISENSE HIVIEW TECH. CO., LTD.. Invention is credited to Yu Chen, Dabo Guo, Wei Li, Chenzhi Wan, Guofeng Yan, Haixiang Zhang.
Application Number | 20150301346 14/789051 |
Document ID | / |
Family ID | 45810061 |
Filed Date | 2015-10-22 |
United States Patent
Application |
20150301346 |
Kind Code |
A1 |
Li; Wei ; et al. |
October 22, 2015 |
LIGHT SOURCE MODULE FOR STEREOSCOPIC DISPLAY, IMAGING DEVICE FOR
STEREOSCOPIC DISPLAY AND STEREOSCOPIC DISPLAY SYSTEM
Abstract
A light source module for stereoscopic display includes
multi-primary color lasers which output the light with the same
polarization direction. Respective lasers are divided into two
groups according to the wavelengths of the output light. A light
combiner is provided in the output light path of each laser group
and is used for combining the output light of all lasers in the
group into one output light path. The light source module further
includes a polarization conversion rotary member, and the
polarization direction of the two output light is periodically and
alternately rotated by 90 degree by self-rotation of the
polarization conversion rotary member. An imaging device for
stereoscopic display includes the light source module for
stereoscopic display, the light combiner and a first optical
imaging modulator and a second optical imaging modulator. A
stereoscopic display system includes the imaging device for
stereoscopic display and a projection lens sub-system.
Inventors: |
Li; Wei; (Qingdao, CN)
; Chen; Yu; (Qingdao, CN) ; Yan; Guofeng;
(Qingdao, CN) ; Guo; Dabo; (Qingdao, CN) ;
Wan; Chenzhi; (Qingdao, CN) ; Zhang; Haixiang;
(Qingdao, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HISENSE HIVIEW TECH. CO., LTD. |
Qingdao |
|
CN |
|
|
Assignee: |
HISENSE HIVIEW TECH. CO.,
LTD.
Qingdao
CN
|
Family ID: |
45810061 |
Appl. No.: |
14/789051 |
Filed: |
July 1, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13817471 |
Feb 18, 2013 |
|
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PCT/CN2010/076735 |
Sep 8, 2010 |
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14789051 |
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Current U.S.
Class: |
353/8 ; 353/121;
362/19 |
Current CPC
Class: |
G02B 30/25 20200101;
G02B 30/24 20200101; G03B 21/005 20130101; G03B 21/2033 20130101;
H04N 13/363 20180501; G03B 21/206 20130101; G03B 21/2073 20130101;
H04N 13/365 20180501; H04N 13/341 20180501 |
International
Class: |
G02B 27/22 20060101
G02B027/22; G03B 21/00 20060101 G03B021/00; G03B 21/20 20060101
G03B021/20; G02B 27/26 20060101 G02B027/26 |
Claims
1. A device with a stereoscopic light source, comprising: a first
laser generator configured to generate a first laser beam having a
first polarization and a first wavelength; a second laser generator
configured to generate a second laser beam having a second
polarization and a second wavelength different from the first
wavelength; and a polarization conversion element configured to
receive the first laser beam and the second laser beam, and
periodically rotate the first polarization of the first laser beam
and the second polarization of the second laser beam with a
predetermined degree so that the first laser beam and second laser
beam form a pair of laser beams with periodically rotated
orthogonal polarizations.
2. The device of claim 1, further comprising a first light
combining element when the first laser generator comprises a first
plurality of laser generators, wherein each of the first plurality
of laser generators is configured to generate a laser beam with the
first polarization, and the first light combining element is
configured to combine the laser beams generated by the first
plurality of laser generators into the first laser beam; and a
second light combining element when the second laser generator
comprises a second plurality of laser generators, wherein each of
the second plurality of laser generators is configured to generate
a laser beam with the second polarization, and the second light
combining element is configured to combine the laser beams
generated by the second plurality of laser generators into the
second laser beam
3. The device of claim 2, wherein the second laser beam comprises
one of a red laser beam, a blue laser beam, and a green laser beam,
whichever is brighter; the second laser beam comprises a remainder
of the red laser, the blue laser, and the green laser.
4. The device of claim 1, wherein the polarization conversion
element is rotatable the first polarization and the second
polarization at a frequency higher than a visual persistence time
of human being.
5. The device of claim 1, wherein the first polarization parallels
to the second polarization; and the polarization conversion element
is further configured to alternatively rotate the first
polarization and the second polarization during a period of
polarization rotation
6. The device of claim 5, wherein the polarization conversion
element comprises a sheet-shaped structure rotatable about an axis,
the polarization conversion elements comprising: a first region
being a polarization changing region to the first laser beam and
the second laser beam; and a second region being a polarization
non-changing region to the first laser beam and the second laser
beam, wherein the first region and second region are so arranged
that when the polarization conversion element rotates about the
axis, the first laser beam is incident to the first region when the
second laser beam is incident to the second region, and the first
laser beam is incident to the second region when the second laser
beam is incident to the first region.
7. The device of claim 6, wherein the first region is occupied by a
half-wave plate, and the predetermined degree is 90 degree.
8. The device of claim 7, wherein the axis is perpendicular to the
sheet-shaped structure.
9. The device of claim 7, wherein the axis passes through the
sheet-shaped structure.
10. The device of claim 6, wherein the polarization conversion
element is a sheet-shaped half-wave plate rotatable about an axis
passing through the sheet-shape structure, and when the
polarization conversion element rotates about the axis, the
polarization conversion element alternatively passes through a
light path of the first laser beam and a light path of the second
laser beam.
11. The device of claim 1, further comprising: a beam combining
element configured to receive the first laser beam and the second
laser beam output from the polarization conversion element and
combine the first laser beam and the second laser beam into a
combined laser beam.
12. The device of claim 11, further comprising: a polarization beam
splitter configured to split the combined laser beam into a
p-polarized component and an s-polarized component; a first optical
image modulator configured to receive the p-polarized component;
and a second optical image modulator configured to receive the
s-polarized component.
13. The device of claim 1, wherein the first polarization and the
second polarization are p-polarization or s-polarization; the
p-polarized component comprises a first image signal; the first
optical image modulator is configured to modulate the p-polarized
component according to the first image signal; the s-polarized
component comprises a second image signal; and the second optical
image modulator is configured to modulate the s-polarized component
according to the second image signal.
14. A method for generating a stereoscopic image, comprising:
generating a first laser beam having a first polarization and a
first wavelength; generating a second laser beam having a second
polarization a second wavelength different from the first
wavelength; and periodically rotating the first polarization of the
first laser beam and the second polarization of the second laser
beam with 90 degree so that the first laser beam and second laser
beam form a laser beam pair with periodically rotated orthogonal
polarizations, wherein a p-polarization component of the laser beam
pair comprises a first image signal, and an s-polarization
component of the laser beam pair comprises a second image
signal.
15. The method of claim 14, wherein the second laser beam comprises
one of a red laser, a blue laser, and a green laser, whichever is
brighter; the second laser beam comprises a remainder of the red
laser, the blue laser, and the green laser.
16. The method of claim 14, wherein the first polarization and the
second polarization are rotated at a frequency higher than a visual
persistence time of human being.
17. The method of claim 14, wherein the first polarization
parallels the second polarization; and the first polarization and
the second polarization are alternatively rotated during a period
of polarization rotation.
18. The method of claim 17, wherein the periodically and
alternatively rotating of the first polarization and the second
polarization comprises: rotating a sheet-shaped structure, wherein
the sheet-shaped structure comprises a first region occupied by a
half-wave plate; and a second region being a polarization
non-changing region to the first laser beam and the second laser
beam, respectively transmitting the first laser beam and the second
laser beam through the sheet-shaped structure so that the first
laser beam is incident to the first region when the second laser
beam is incident to the second region, and the first laser beam is
incident to the second region when the second laser beam is
incident to the first region.
19. The method of claim 14, further comprising: combining the first
laser beam and the second laser beam into a combined laser beam
after the periodical rotating of the first polarization and the
second polarization.
20. The method of claim 19, further comprising: splitting the
combined laser beam into a p-polarized component and an s-polarized
component; modulating the p-polarized component according to the
first image signal; and modulating the s-polarized component
according to the second image signal.
Description
PRIORITY STATEMENT
[0001] This application is a continuation of U.S. patent
application Ser. No. 13/817,471 (still pending), filed on Feb. 18,
2013, which is a National Stage application of International
Application No. PCT/CN2010/076735, filed on Sep. 8, 2010, in the
State Intellectual Property Office of the People's Republic of
China, the disclosures of which are incorporated herein in their
entirety by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to the field of stereoscopy,
and in particular to a stereoscopic light source module, a
stereoscopic imaging device and a stereoscopic display system.
BACKGROUND OF THE INVENTION
[0003] With the continuous improvement in the quality of life,
higher requirements for display technologies have been put forward.
3D, stereoscopic technology is one of the most important trends in
current development of display technologies.
[0004] Currently, there are the following categories of
stereoscopic technology.
[0005] Dual-Color Glasses Based Method:
[0006] In this method, a scene to be displayed on the screen is
filtered with a driver program. Specifically, the image intended
for the left eye is filtered to remove red, and the image intended
for the right eye is filtered to remove cyan (blue and green). The
viewer wears a pair of dual-color glasses. A filter lens over the
left eye blocks red, and a filter lens over the right eye blocks
cyan. Therefore, the left eye sees only the image intended for the
left eye, and the right eye sees only the image intended for the
right eye. The brain fuses both images into perception of regular
colors. This is the lowest cost method of stereoscopic technology,
but it is generally only suitable for scenes where color is not an
important factor. As to other types of scenes, it may cause
discomfort of viewers and severe color distortion due to the loss
of color information.
[0007] Active Stereoscopic Method:
[0008] In this method, a driver program alternately transmits left
eye and right eye images, for example, a left eye image at a first
frame, a right eye image at a second frame, another left eye image
at a third frame, and so forth. The viewer wears a pair of shutter
glasses in synchronization with the display device in a wired or
wireless manner. While presenting the left eye image, the display
device opens the shutter in the left glass and closes the shutter
in the right glass. While presenting the right eye image, the
display device opens the shutter in the right glass and closes the
shutter in the left glass. According to the phenomenon of
persistence of vision, an afterimage is thought to persist in front
of the eye whose view is blocked, and any viewer within the range
can see a three-dimensional scene wearing a pair of the
stereoscopic glasses. Generally, the shutters in the glasses are
implemented with liquid crystals. The liquid crystal layer can be
switched between transparent and dark by an applied electrical
signal. This method reduces the brightness of the image in half,
and has certain frequency requirements on the refresh rates of the
display device and the shutters in the glasses, demanding more on
the properties of the display device and the glasses, and resulting
in higher manufacturing cost. Moreover, flicker caused by the
frequent switching of the stereoscopic glasses is displeasing to
the eye, and may tire the viewer.
[0009] Passive Synchronization Stereoscopic Method:
[0010] In this method, a driver program simultaneously outputs left
eye and right eye images. The left eye and right eye images are
projected using two projectors. A polarizing filter is provided in
front of the projector for the left eye image, and an orthogonal
polarizing filter is provided in front of the projector for the
right eye image. The viewer wears a pair of glasses, which also
contain a pair of polarizing filters oriented the same as the
projectors. According to the polarizing effect, each eye only sees
the image intended for the eye itself. Currently, this is the
stereoscopic method producing the best imaging results. However,
since light emitted from the projector light source is like natural
light, the polarizing filters on the outputs of the projectors cost
50% of the light energy, reducing the utilization rate of the light
energy. Moreover, the use of two projection subsystems is costly,
requires a large space and may cause inconvenience in installation
and moving.
[0011] Due to its advantages such as wide color gamut and low
energy consumption, laser-based display technology is considered
one of the prominent, next generation display technologies.
Combining laser-based display with stereoscopic projection is the
current trend, one implementation of which is an active
stereoscopic method. The screen alternately presents left eye and
right eye images at twice the frequency, and the glasses
dynamically block one of the eyes. That is, present the left eye
image while blocking the right eye's view, and present the right
eye image while blocking the left eye's view, so that the eyes are
provided with different images, which are fused by the brain into
perception of a three-dimensional scene. Multi-color display makes
use of time-domain control, e.g., lights of different wavelengths
are transmitted during different time slots according to a color
wheel. Since each wavelength is illuminated separately during one
time slot, the utilization rate of the laser light source is low.
Moreover, the existing stereoscopic projection method includes two
projection subsystems, one for projecting the left eye image and
the other for projecting the right eye image, therefore, the size
of the projection system is large, installation and moving
inconvenience may be caused, and manufacturing and production costs
are high. Furthermore, each of the left eye and right eye images
uses only half of the light energy output from the laser, resulting
in a low brightness of the image.
SUMMARY OF THE INVENTION
[0012] In view of the above, an object of an embodiment of the
present invention is to provide a stereoscopic light source module,
a stereoscopic imaging device and a stereoscopic display system,
which can improve the utilization rate of the light source.
[0013] In order to achieve the above object, an embodiment of the
present invention provides a stereoscopic light source module,
including a plurality of primary-color lasers, wherein lights
output by the lasers have the same polarization indirection; the
plurality of primary-color lasers are divided into two groups
according to the wavelengths of their output lights, so that lasers
whose output lights are of the same wavelength belong to the same
group, and lasers in each of the groups output lights of at least
one wavelength; an output light path of each of the groups is
provided with a light combining element, and the combining element
is adapted to combine the lights output from all the lasers in one
group into one beam;
[0014] the stereoscopic light source module further includes a
polarization conversion rotary element arranged in the paths of the
two beams output from the light combining elements, and the
polarization conversion rotary element is adapted to periodically,
alternately change polarization directions of the two beams output
from the light combining elements by 90 degrees.
[0015] Preferably, the polarization conversion rotary element may
have a roulette-based structure; the surface of the polarization
conversion rotary element is perpendicular to a transmission
direction of the two beams obtained from the light combining
elements for the two groups; a rotation axis of the polarization
conversion rotary element is parallel to the transmission direction
of the two beams obtained from the light combining elements for the
two groups;
[0016] the polarization conversion rotary element is divided into
polarization conversion regions and polarization non-changing
regions that are positioned alternately in the direction of
rotation; each of the polarization conversion regions is a
half-wave plate for changing the polarization direction of light
passing through it by 90 degrees; each of the polarization
non-changing regions is a transparent region that does not make any
change to the polarization direction of light passing through it;
during rotation of the polarization conversion rotary element, one
beam from one group strikes a polarization conversion region, while
one beam from the other group strikes a polarization non-changing
region.
[0017] Preferably, the polarization conversion rotary element may
have a sheet-shaped structure; the surface of the sheet-shaped
structure is perpendicular to a plane formed by transmission paths
of the two beams obtained from the light combining elements for the
two groups; and the rotation axis of the polarization conversion
rotary element is perpendicular to a plane formed by the
transmission paths of the two beams obtained from the light
combining elements for the two groups;
[0018] the polarization conversion rotary element is divided into a
first region and a second region along the direction from one of
the two incident beams to the other; the first region is a
half-wave plate for changing the polarization direction of light
passing through it by 90 degrees; the second region is a
transparent region that does not make any change to the
polarization direction of light passing through it; the rotation
axis of the polarization conversion rotary element is positioned at
an interface between the first region and the second region; during
rotation of the polarization conversion rotary element, one beam
from one group strikes the first region, while one beam from the
other group strikes the second region.
[0019] Preferably, the polarization conversion rotary element may
have a sheet-shaped structure, the surface of the sheet-shaped
structure is perpendicular to a plane formed by transmission paths
of the two beams obtained from the light combining elements for the
two groups; the rotation axis of the polarization conversion rotary
element is perpendicular to a plane formed by the transmission
paths of the two beams obtained from the light combining elements
for the two groups, and is positioned at one end of the
polarization conversion rotary element;
[0020] the polarization conversion rotary element is formed by a
half-wave plate which is adapted to change the polarization
direction of light passing through it by 90 degrees; during
rotation of the polarization conversion rotary element, the
polarization conversion rotary element alternately cuts through the
two beams from the two groups.
[0021] Preferably, lasers in each of the groups may output lights
in an alternating manner.
[0022] Preferably, the plurality of primary-color lasers may
include three lasers for outputting red, green and blue lights,
wherein the red and blue lasers belong to one group and the green
laser belongs to the other group.
[0023] In another aspect, an embodiment of the present invention
provides a stereoscopic imaging device, including the stereoscopic
light source module as described above, a beam combining element, a
polarizing splitting and combining element and a first optical
imaging modulator and a second optical imaging modulator, wherein
the beam combining element is adapted to combine two beams output
by the stereoscopic light source module into one beam; the
polarizing splitting and combining element is adapted to receive
the one beam output by the beam combining element, divide it into a
p-polarized component and an s-polarized component, and input the
p-polarized component and the s-polarized component to the first
optical imaging modulator and the second optical imaging modulator
respectively; the first optical imaging modulator is adapted to
modulate the p-polarized incident light according to an image
signal; the second optical imaging modulator is adapted to modulate
the s-polarized incident light according to an image signal; the
polarizing splitting and combining element is also adapted to
combine the modulated, p-polarized and s-polarized lights from the
first optical imaging modulator and the second optical imaging
modulator into one beam.
[0024] Preferably, the beam combining element may include a
focusing lens and a light uniforming device; the focusing lens is
adapted to focus the two beams output by the stereoscopic light
source module to the light uniforming device; the light uniforming
device is adapted to uniform the two beams focused by the
stereoscopic light source module, and output one uniform beam.
[0025] Preferably, the first optical imaging modulator and the
second optical imaging modulator may be liquid crystal devices or
Digital Micromirror Device (DMD) chips.
[0026] In another aspect, an embodiment of the present invention
provides a stereoscopic display system, including the stereoscopic
imaging device as described above and a projection lens subsystem
for projecting the output light from the stereoscopic imaging
device.
[0027] In the stereoscopic light source module, the stereoscopic
imaging device and the stereoscopic display system according to the
embodiments of the present invention, the lasers are divided into
two groups according to the wavelengths of their output lights, and
the lasers in each of the groups output lights in an alternating
manner. Hence, time-domain control is achieved inside the group,
but light output from one group as a whole is continuous.
Therefore, compared with the prior art where all the lasers are
illuminated sequentially, the stereoscopic light source module, the
stereoscopic imaging device and the stereoscopic display system
according to the embodiments of the present invention can improve
the utilization rate of the light source. Especially in the case
where a group has only a laser outputting light of one wavelength,
the group always outputs light, resulting in an even higher
utilization rate of the light source.
[0028] Moreover, the stereoscopic light source module, the
stereoscopic imaging device and the stereoscopic display system
according to the embodiments of the present invention use one
projection subsystem instead of two projection subsystems one for
each eye, which improves the utilization rate of the light source,
lowers manufacturing and processing costs, and reduces the size of
the device and the system. In addition, reducing the number of
optical devices can further lower maintenance expense of the device
and the system, e.g., by reducing the time required for light path
calibration.
[0029] Furthermore, in the stereoscopic light source module
according to the embodiment of the present invention, light of any
wavelength from the light combining element is output alternately
between p-polarized and s-polarized over time; and whether it is
p-polarized or s-polarized, the power of it is almost equal to the
total output power of the laser whose output light is of the
wavelength. Compared with the prior art where the polarized light
output by a laser is divided simultaneously into a p-polarized
component and an s-polarized component, the stereoscopic light
source module according to the embodiment of the present invention
has a higher power of the s-polarized output and a higher power of
the p-polarized output. Furthermore, the stereoscopic imaging
device according to the embodiment of the present invention forms
s-polarized and p-polarized images using the s-polarized light and
the p-polarized light output from the stereoscopic light source
module as described above. Therefore, with the same laser driving
power, the brightness of the eventual s-polarized and p-polarized
images formed by the stereoscopic imaging device according to the
embodiment of the present invention is higher than the prior art.
The stereoscopic display system according to the embodiment of the
present invention uses the stereoscopic imaging device as described
above, also increasing the brightness of the eventual s-polarized
and p-polarized images.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] For a better illustration of the technical solutions in the
embodiments of the present invention or in the prior art,
accompanying drawings used in the description of the embodiments or
the prior art are described briefly below. Clearly, the
accompanying drawings described below are merely some of the
embodiments of the present invention; and other drawings can be
obtained by those skilled in the art based on these drawings
without inventive effort.
[0031] FIG. 1 is a schematic diagram illustrating a stereoscopic
light source module provided by an embodiment of the present
invention;
[0032] FIG. 2 is a schematic diagram illustrating a stereoscopic
light source module according to an embodiment of the present
invention;
[0033] FIG. 3 is a front view of a polarization conversion rotary
element shown in FIG. 2;
[0034] FIG. 4 is a schematic diagram illustrating a stereoscopic
light source module according to an embodiment of the present
invention;
[0035] FIG. 5 is a front view of a polarization conversion rotary
element shown in FIG. 4;
[0036] FIG. 6 is a schematic diagram illustrating a stereoscopic
light source module according to an embodiment of the present
invention; and
[0037] FIG. 7 is a schematic diagram illustrating a stereoscopic
imaging device provided by an embodiment of the present
invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0038] For a better understanding of the objects, technical
solutions and advantages of the embodiments of the present
invention, the technical solutions in the embodiments of the
present invention will be described in conjunction with the
accompanying drawings. Clearly, the embodiments described herein
are merely some of the embodiments of the present invention. Any
other embodiment obtained by those skilled in the art without
inventive effort based on the embodiments described herein shall
fall within the scope of protection of the present invention.
[0039] FIG. 1 is a schematic diagram illustrating a stereoscopic
light source module provided by an embodiment of the present
invention. As shown in FIG. 1, the stereoscopic light source module
includes a plurality of primary-color lasers 11. The plurality of
primary-color lasers include, e.g., 5 lasers denoted from L1 to L5
as shown in FIG. 1. Lights output by the lasers in the plurality of
primary-color lasers 11 have the same polarization direction, e.g.,
all p-polarized or all s-polarized. The lasers in the plurality of
primary-color lasers 11 are divided into two groups according to
the wavelengths of their output lights, so that lasers whose output
lights are of the same wavelength belong to the same group, and
lasers in each of the groups output lights of at least one
wavelength. Assuming that the wavelengths of the output lights of
the lasers L1-L5 in FIG. 1 are .lamda.1-.lamda.5 respectively, the
lasers L1 and L2 whose output lights are of the wavelengths
.lamda.1 and .lamda.2 can be divided into a group G1; the lasers
L3-L5 whose output lights are of the wavelengths .lamda.3-.lamda.5
can be divided into a group G2. The stereoscopic light source
module further includes light combining elements 12. A light
combining element 12 is used to combine the lights output from all
the lasers in one group into one beam. Hence, by the light
combining elements 12, the lights output from the two groups are
combined into two beams. In practice, if the number of lasers in
each of the two groups is greater than or equal to 2, both groups
needs to be provided with a corresponding light combining element.
For example, as shown in FIG. 1, a light combining element 12a is
arranged in the output light path of the first group G1, and a
light combining element 12b is arranged in the output light path of
the second group G2. The polarized lights output by the lasers L1
and L2 in the same polarization direction are combined into one
beam by the light combining element 12a, and the polarized lights
output by the lasers L3-L5 in the same polarization direction are
combined into one beam by the light combining element 12b. Clearly,
in the case where a group has only one laser, the output light path
of the laser may not be provided with a light combining
element.
[0040] Since the lights output by all the lasers have the same
polarization direction, the two beams obtained through the light
combining elements are also lights in the same polarization
direction that do not have changed polarization directions.
[0041] A polarization conversion rotary element 13 is arranged in
the paths of the two beams output from the light combining elements
12. The polarization conversion rotary element 13 may actively
rotate driven by a driving structure, so as to periodically,
alternately change the polarization directions of the two beams
from the light combining elements 12 by 90 degrees. For example, in
the case as shown in FIG. 1, assuming that the polarized lights
output by the all the lasers are p-polarized, the two beams
obtained from the light combining elements 12a and 12b are also
p-polarized. The two p-polarized beams are of different
wavelengths. The polarization conversion rotary element 13
alternately converts the two p-polarized beams into s-polarized.
That is, the polarization conversion rotary element 13 has two
operating states. In a first operating state, the polarization
conversion rotary element 13 converts the p-polarized beam obtained
from the light combining element 12a into s-polarized, without
changing the polarization direction of the p-polarized beam
obtained from the light combining element 12b. As a result, in the
first operating state, by the polarization conversion rotary
element 13, the stereoscopic light source module outputs one
p-polarized beam and one s-polarized beam, with the p-polarized
beam including lights of the wavelengths .lamda.1 and .lamda.2 and
the s-polarized beam including lights of the wavelengths
.lamda.3-.lamda.5. In a second operating state, the polarization
conversion rotary element 13 converts the p-polarized beam obtained
from the light combining element 12b into s-polarized, without
changing the polarization direction of the p-polarized beam
obtained from the light combining element 12a. As a result, the
stereoscopic light source module outputs one s-polarized beam and
one p-polarized beam, with the p-polarized beam including lights of
the wavelengths .lamda.3-.lamda.5 and the s-polarized beam
including lights of the wavelengths .lamda.1 and .lamda.2.
[0042] The lasers in each of the groups output lights in an
alternating manner, achieving time-domain control.
[0043] As can be seen, in the stereoscopic light source module
according to the embodiment of the present invention, the lasers
are divided into two groups according to the wavelengths of their
output lights, and the lasers in each of the groups output lights
in an alternating manner. Hence, time-domain control is achieved
inside the group, but light output from one group as a whole is
continuous. Therefore, compared with the prior art where all the
lasers are illuminated sequentially, the stereoscopic light source
module, the stereoscopic imaging device and the stereoscopic
display system according to the embodiment of the present invention
can improve the utilization rate of the light source. Especially in
the case where a group has only a laser outputting light of one
wavelength, the group always outputs light, resulting in an even
higher utilization rate of the light source.
[0044] Moreover, the light output from the stereoscopic light
source module according to the embodiment of the present invention
allows a projection subsystem to simultaneously output s-polarized
and p-polarized images. Compared with the prior art which uses two
projection subsystems and two corresponding light source modules,
the stereoscopic light source module according to an embodiment of
the present invention creates the preconditions for reducing the
size of the projection system as well as reducing its manufacturing
and processing costs.
[0045] Furthermore, in the stereoscopic light source module
according to the embodiment of the present invention, light of any
wavelength from the light combining element is output alternately
between p-polarized and s-polarized over time; and whether it is
p-polarized or s-polarized, the power of it is almost equal to the
total output power of the laser whose output light is of the
wavelength. Compared with the prior art where the polarized light
output by a laser is divided simultaneously into a p-polarized
component and an s-polarized component, the stereoscopic light
source module according to the embodiment of the present invention
has a higher power of the s-polarized output and a higher power of
the p-polarized output, thus increasing the brightness of the
eventual s-polarized and p-polarized images.
[0046] In practice, the polarization conversion rotary element 13
may have various structures that meet the above requirements,
examples of which are given below.
Embodiment 1
[0047] FIG. 2 is a schematic diagram illustrating a stereoscopic
light source module according to an embodiment of the present
invention. In this embodiment, the stereoscopic light source module
may include three lasers for outputting red, green and blue lights
respectively. The three lasers will be referred to as Lr, Lg and Lb
hereinafter, and it is assumed that the polarized lights output by
the three lasers are all p-polarized.
[0048] Generally, the lasers that are divided into one group are
driven sequentially to output lights in an alternating manner. When
there are three lasers in the entire stereoscopic light source, the
grouping of lasers may depend on the actual needs of the user. For
example, tests showed that, of red, green and blue lasers, driven
by the same power, the luminance of green light output by the green
laser is the largest. Therefore, in order to improve the brightness
of display at a low cost, it is desirable to increase the output
time of the green laser. Based on such consideration, the green
laser Lg may be divided into one group G2, and the rest of lasers,
i.e., the red laser Lr and the blue laser Lb, may be divided into
another group G1.
[0049] In the embodiment, only the group G1 includes multiple
lasers, and only the output light path of the red laser Lr and the
blue laser Lb in group G1 is provided with a light combining
element. As shown in FIG. 2, the light combining element may
include a first reflecting mirror 121 and a first dichroic mirror
122. P-polarized blue light output by the blue laser Lb strikes the
surface of the first dichroic mirror 122 after being reflected by
the first reflecting mirror 121, and reflects off the first
dichroic mirror 122. P-polarized red light output by the red laser
Lr passes through the first dichroic mirror 122, and integrates
with the p-polarized blue light reflected by the first dichroic
mirror 122 into to one beam.
[0050] In the embodiment, the polarization conversion rotary
element 13a may have a roulette-based structure. FIG. 3 shows a
front view of the polarization conversion rotary element 13a in the
embodiment. The surface of the polarization conversion rotary
element 13a (i.e., the surface of the roulette) is perpendicular to
the transmission direction of the two beams obtained from the light
combining elements for the groups G1 and G2; and the rotation axis
14a is parallel to the transmission direction of the two beams
obtained from the light combining elements for the groups G1 and
G2. Hence, the rotation axis 14a is perpendicular to the plane of
the polarization conversion rotary element 13a.
[0051] As shown in FIG. 3, the polarization conversion rotary
element 13a can be divided into polarization conversion regions
13a1 and polarization non-changing regions 13a2 that are positioned
alternately in the direction of rotation. In FIG. 3, as an example,
the polarization conversion rotary element 13a includes two
polarization conversion regions 13a1 and two polarization
non-changing regions 13a2 that are positioned alternately in the
direction of rotation. Clearly, in practice, the number of the
polarization conversion regions and the number of the polarization
non-changing regions can be determined according to actual needs,
i.e., the number of the divided regions on the polarization
conversion rotary element 13a can be determined according to actual
needs.
[0052] The polarization conversion region 13a1 may be a half-wave
plate for changing the polarization direction of light passing
through it by 90 degrees. The polarization non-changing region 13a2
may be a transparent region that does not make any change to the
polarization direction of light passing through it, e.g., the
polarization non-changing region 13a2 may be made of glass. During
the rotation of the polarization conversion rotary element, one
beam from one group strikes a polarization conversion region, while
one beam from the other group strikes a polarization non-changing
region.
[0053] Driven by a driving device, the polarization conversion
rotary element 13a having a roulette-based structure rotates around
the rotation axis 14a, so that the polarization conversion regions
13a1 and the polarization non-changing regions 13a2 on the
polarization conversion rotary element 13a alternately cut through
the light path of the beam of red and blue lights from the group G1
and the light path of the beam of green light from the group G2.
Specifically, in a first operating state of the polarization
conversion rotary element 13a, a polarization conversion region
13a1 on the polarization conversion rotary element 13a is in the
light path of the beam from the group G1, and a polarization
non-changing region 13a2 on the polarization conversion rotary
element 13a is in the light path of the beam from the group G2. At
this moment, p-polarized red light and p-polarized blue light from
the group G1 pass through the half-wave plate of the polarization
conversion region 13a1, and are changed by 90 degrees in their
polarization directions, resulting in s-polarized red output and
s-polarized blue output; p-polarized green light from the group G2
passes through the polarization non-changing region 13a2, and is
not changed in its polarization direction, resulting in p-polarized
green output. Therefore, in the first operating state, the
stereoscopic light source module in the embodiment outputs
s-polarized red light, s-polarized blue light and p-polarized green
light; and whether it is s-polarized or p-polarized, the power is
almost equal to the power of the output light of the corresponding
laser. Similarly, in a second operating state of the polarization
conversion rotary element 13a, p-polarized red light and
p-polarized blue light from the group G1 pass through the
polarization non-changing region 13a2 and are not changed in their
polarization directions, resulting in p-polarized red output and
p-polarized blue output; p-polarized green light from the group G2
passes through the half-wave plate of the polarization conversion
region 13a1, and is changed by 90 degrees in its polarization
direction, resulting in s-polarized green output. Therefore, in the
second operating state, the stereoscopic light source module in the
embodiment outputs p-polarized red light, p-polarized blue light
and s-polarized green light; and whether it is s-polarized or
p-polarized, the power is almost equal to the power of the output
light of the corresponding laser.
[0054] As can be seen, in the stereoscopic light source module
according to the embodiment of the present invention, the lasers in
each of the groups output lights in an alternating manner, but
light output from one group as a whole is continuous. Compared with
the prior art where all the lasers are illuminated sequentially,
the stereoscopic light source module according to the embodiment of
the present invention can improve the utilization rate of the light
source. Moreover, since the group G2 has only a laser outputting
green light, the group always outputs light, resulting in an even
higher utilization rate of the light source.
[0055] Furthermore, based on the continuous rotation of the
polarization conversion rotary element 13a having a roulette-based
structure, light of any wavelength from the stereoscopic light
source module is output alternately between p-polarized and
s-polarized. For each wavelength, whether the light is p-polarized
or s-polarized, the power of it is almost equal to the total output
power of the laser whose output light is of the wavelength, thus
increasing the brightness of the displayed image.
Embodiment 2
[0056] FIG. 4 is a schematic diagram illustrating a stereoscopic
light source module according to another embodiment of the present
invention. The difference between the stereoscopic light source
module in this embodiment and the stereoscopic light source module
in Embodiment 1 lies in the structure of the polarization
conversion rotary element.
[0057] The stereoscopic light source module in this embodiment may
include three lasers for outputting red, green and blue lights
respectively, denoted as Lr, Lg and Lb respectively. It is assumed
that the polarized lights output by the three lasers are all
p-polarized. The green laser Lg may be divided into a separate
group G2, and the red laser Lr and the blue laser Lb may be divided
into another group G1.
[0058] In the embodiment, p-polarized red light and p-polarized
blue light output by the red laser Lr and the blue laser Lb may be
combined into one beam through a first reflecting mirror 121 and a
first dichroic mirror 122.
[0059] In the embodiment, the polarization conversion rotary
element 13b may have a sheet-shaped structure. FIG. 5 shows a front
view of the polarization conversion rotary element 13b according to
the embodiment. The surface of the polarization conversion rotary
element 13b (i.e., the surface of the sheet-shaped structure) is
perpendicular to the plane formed by the transmission paths of the
two beams obtained from the light combining elements for the groups
G1 and G2; and the rotation axis 14a of the polarization conversion
rotary element 13b is perpendicular to the plane formed by the
transmission paths of the two beams obtained from the light
combining elements for the groups G1 and G2.
[0060] The polarization conversion rotary element 13b can be
divided into a first region 13b1 and a second region 13b2 along the
direction from one of the two incident beams (i.e., the two beams
from the groups G1 and G2) to the other. The first region 13b1 may
be a half-wave plate for changing the polarization direction of
light passing through it by 90 degrees. The second region 13b2 may
be a transparent region that does not make any change to the
polarization direction of light passing through it.
[0061] Driven by a driving device, the polarization conversion
rotary element 13b rotates around its rotation axis 14b, i.e., in a
direction perpendicular to the plane formed by the transmission
paths of the two beams from the groups G1 and G2, so that the first
region 13a1 and the second region 13a2 on the polarization
conversion rotary element 13a alternately cut through the light
path of the beam of red and blue lights from the group G1 and the
light path of the beam of green light from the group G2.
[0062] Specifically, in a first operating state during the rotation
of the polarization conversion rotary element 13b, the first region
13b1 on the polarization conversion rotary element 13b is in the
light path of the beam from the group G1, and the second region
13b2 on the polarization conversion rotary element 13b is in the
light path of the beam from the group G2. At this moment,
p-polarized red light and p-polarized blue light from the group G1
pass through the half-wave plate of the first region 13b1, and are
changed by 90 degrees in their polarization directions, resulting
in s-polarized red output and s-polarized blue output; p-polarized
green light from the group G2 passes through the second region
13b2, and is not changed in its polarization direction, resulting
in p-polarized green output. Therefore, in the first operating
state, the stereoscopic light source module in the embodiment
outputs s-polarized red light, s-polarized blue light and
p-polarized green light; and whether it is s-polarized or
p-polarized, the power is almost equal to the power of the output
light of the corresponding laser. Similarly, in a second operating
state of the polarization conversion rotary element 13b,
p-polarized red light and p-polarized blue light from the group G1
pass through the second region 13b2 and are not changed in their
polarization directions, resulting in p-polarized red output and
p-polarized blue output; p-polarized green light from the group G2
passes through the half-wave plate of the first region 13b1, and is
changed by 90 degrees in its polarization direction, resulting in
s-polarized green output. Therefore, in the second operating state,
the stereoscopic light source module in the embodiment outputs
p-polarized red light, p-polarized blue light and s-polarized green
light; and whether it is s-polarized or p-polarized, the power is
almost equal to the power of the output light of the corresponding
laser.
[0063] As can be seen, in the stereoscopic light source module
according to the embodiment of present invention, the lasers in
each of the groups output lights in an alternating manner, but
light output from one group as a whole is continuous. Compared with
the prior art where all the lasers are illuminated sequentially,
the stereoscopic light source module according to the embodiment of
the present invention can improve the utilization rate of the light
source. Moreover, since the group G2 has only a laser outputting
green light, the group always outputs light, resulting in an even
higher utilization rate of the light source.
[0064] Furthermore, based on the continuous rotation of the
polarization conversion rotary element 13b having a sheet-shaped
structure, light of any wavelength from the stereoscopic light
source module is output alternately between p-polarized and
s-polarized over time. For each wavelength, whether the light is
p-polarized or s-polarized, the power of it is almost equal to the
total output power of the laser whose output light is of the
wavelength, thus increasing the brightness of the displayed
image.
Embodiment 3
[0065] FIG. 6 is a schematic diagram of a stereoscopic light source
module according to another embodiment of the present invention.
The difference between the stereoscopic light source module in this
embodiment and those in Embodiment 1 and Embodiment 2 lies in the
structure of the polarization conversion rotary element.
[0066] The stereoscopic light source module in this embodiment may
include three lasers for outputting red, green and blue lights
respectively, denoted as Lr, Lg and Lb respectively. It is assumed
that the polarized lights output by the three lasers are all
p-polarized. The green laser Lg may be divided into a separate
group G2, and the red laser Lr and the blue laser Lb may be divided
into another group G1. P-polarized red light and p-polarized blue
light output by the red laser Lr and the blue laser Lb may be
combined into one beam through a first reflecting mirror 121 and a
first dichroic mirror 122.
[0067] In the embodiment, the polarization conversion rotary
element 13c may also have a sheet-shaped structure. The difference
between the polarization conversion rotary element 13c in the
embodiment and that in Embodiment 2 is that the polarization
conversion rotary element 13c is formed by a half-wave plate. The
surface of the polarization conversion rotary element 13c (i.e.,
the surface of the sheet-shaped structure) is perpendicular to the
plane formed by the transmission paths of the two beams obtained
from the light combining elements for the groups G1 and G2; the
rotation axis 14c of the polarization conversion rotary element 13c
is perpendicular to the plane formed by the transmission paths of
the two beams obtained from the light combining elements for the
groups G1 and G2; and the rotation axis 14c is positioned at one
end of the polarization conversion rotary element 13c. The
half-wave plate of the polarization conversion rotary element 13c
is used to change the polarization direction of light passing
through it by 90 degrees.
[0068] Driven by a driving device, the polarization conversion
rotary element 13c rotates around its rotation axis 14c, so that
the polarization conversion rotary element 13c alternately cuts
through the light path of the beam of red and blue lights from the
group G1 and the light path of the beam of green light from the
group G2.
[0069] Specifically, during the rotation of the polarization
conversion rotary element 13c, when the polarization conversion
rotary element 13c is in the light path of the beam of red and blue
lights from the group G1, p-polarized red light and p-polarized
blue light from the group G1 pass through the half-wave plate on
the polarization conversion rotary element 13c, and are changed by
90 degrees in their polarization directions, resulting in
s-polarized red output and s-polarized blue output; p-polarized
green light from the group G2 does not pass through the
polarization conversion rotary element 13c, and is not changed in
its polarization direction, resulting in p-polarized green output.
When the polarization conversion rotary element 13c is in the light
path of the beam of green light from the group G2, p-polarized red
light and p-polarized blue light from the group G1 does not pass
through the polarization conversion rotary element 13c and are not
changed in their polarization directions, resulting in p-polarized
red output and p-polarized blue output; p-polarized green light
from the group G2 passes through the half-wave plate on the
polarization conversion rotary element 13c, and is changed by 90
degrees in its polarization direction, resulting in s-polarized
green output. In above process, for light of any color, whether it
is output s-polarized or p-polarized, the power is almost equal to
the power of the output light of the corresponding laser.
[0070] As can be seen, in the stereoscopic light source module
according to the embodiment of the present invention, the lasers in
each of the groups output lights in an alternating manner, but
light output from one group as a whole is continuous. Compared with
the prior art where all the lasers are illuminated sequentially,
the stereoscopic light source module according to the embodiment of
the present invention can improve the utilization rate of the light
source. Moreover, since the group G2 has only a laser outputting
green light, the group always outputs light, resulting in an even
higher utilization rate of the light source.
[0071] Furthermore, based on the continuous rotation of the
polarization conversion rotary element 13c having a deflecting
structure, light of any wavelength from the stereoscopic light
source module is output alternately between p-polarized and
s-polarized over time. For each wavelength, whether the light is
p-polarized or s-polarized, the power of it is almost equal to the
total output power of the laser whose output light is of the
wavelength, thus increasing the brightness of the displayed
image.
[0072] An embodiment of the present invention provides a
stereoscopic imaging device. FIG. 7 is a schematic diagram
illustrating the stereoscopic imaging device. The stereoscopic
imaging device includes the stereoscopic light source module 1 as
described above, a beam combining element 2, a polarizing splitting
and combining element 3 and a first optical imaging modulator 41
and a second optical imaging modulator 42. The stereoscopic imaging
device 1 may have any of the structures described in the
embodiments above.
[0073] The beam combining element 2 is used to combine two beams
output by the stereoscopic light source module 1 into one beam. As
discussed above, each of the two beams output by the stereoscopic
light source module 1 includes lights of different wavelengths, and
the polarization directions of the two beams are orthogonal to each
other. The polarization direction of each of the beams changes over
time, e.g., between p-polarized and s-polarized. Therefore, at any
moment, light output by the beam combining element 2 includes both
p-polarized and s-polarized lights. For light of a certain
wavelength in the output light, its polarization direction varies
between p-polarized and s-polarized over time.
[0074] The polarizing splitting and combining element 3 receives
the one beam output by the beam combining element 2, divides it
into a p-polarized component and an s-polarized component, and
inputs the p-polarized component and the s-polarized component to
the first optical imaging modulator 41 and the second optical
imaging modulator 42 respectively. The first optical imaging
modulator 41 is used to modulate the p-polarized incident light
according to an image signal; and the second optical imaging
modulator 42 is used to modulate the s-polarized incident light
according to an image signal. The polarizing splitting and
combining element 3 is also used to combine the modulated,
p-polarized and s-polarized lights from the first optical imaging
modulator 41 and the second optical imaging modulator 42 into one
beam. As show in FIG. 7, the polarizing splitting and combining
element 3 may include 4 Polarizing Beam Splitter (PBS) prisms
301-304. Specifically, the PBS prism 301 divides the one beam
output by the beam combining element 2 into a p-polarized component
and an s-polarized component. The PBS prism 302 reflects the
p-polarized obtained from the PBS prism 301 to the first optical
imaging modulator 41 and inputs the modulated, p-polarized light
from the first optical imaging modulator 41 to the PBS prism 304.
The PBS prism 303 reflects the s-polarized obtained from the PBS
prism 301 to the second optical imaging modulator 42, and inputs
the modulated, s-polarized light from the second optical imaging
modulator 42 to the PBS prism 304. The PBS prism 304 combines the
modulated, p-polarized incident light and the modulated,
s-polarized incident light into one beam.
[0075] The beam combining element 2 may include a focusing lens 21
and a light uniforming device 22. The focusing lens 21 focuses the
two beams output by the stereoscopic light source module 1 to the
light uniforming device 22. The light uniforming device 22 uniforms
the two beams focused by the stereoscopic light source module, and
outputs one uniform beam.
[0076] The first optical imaging modulator and the second optical
imaging modulator may be liquid crystal devices or Digital
Micromirror Device (DMD) chips.
[0077] An operating process of the stereoscopic imaging device will
be described in detail hereinafter. It is assumed that the period
of rotation of a polarization conversion rotary element in the
stereoscopic light source module 1 is T, which also corresponds to
the time for projecting a frame.
[0078] When the polarization conversion rotary element is in a
first time period t1 within the rotation period T, the polarization
conversion rotary element converts p-polarized lights of all
wavelengths output from a first group of lasers into s-polarized,
without changing the polarization directions of p-polarized lights
of all wavelengths output from a second group of lasers. The lasers
of all wavelengths in the first group are driven sequentially in a
time-division multiplexing manner to output polarized lights of
corresponding wavelengths, therefore, the lights of all wavelengths
output from the first group are input to the second optical imaging
modulator 42 in a time-division multiplexing manner. Color channels
of the image signal input to the second optical imaging modulator
42 correspond to the wavelengths of the lights output from the
first group and input to the second optical imaging modulator 42.
Therefore, the s-polarized lights that correspond to all the
wavelengths output from the first group and are input to the second
optical imaging modulator 42 in a time-division multiplexing manner
are modulated synchronously using the corresponding color channels
of the image signal, thereby obtaining part of the s-polarized
frame that consists of the color channels which correspond to all
the wavelengths output from the first group. Similarly, the lights
of all wavelengths output from the second group are input to the
first optical imaging modulator 41 in a time-division multiplexing
manner. Color channels of the image signal input to the first
optical imaging modulator 41 correspond to the wavelengths of the
lights output from the second group and input to the first optical
imaging modulator 41. Therefore, the p-polarized lights that
correspond to all the wavelengths output from the second group and
are input to the first optical imaging modulator 41 in a
time-division multiplexing manner are modulated synchronously using
the corresponding color channels of the image signal, thereby
obtaining part of the p-polarized frame that consists of the color
channels which correspond to all the wavelengths output from the
second group.
[0079] When the polarization conversion rotary element is in a
second time period t2 within the rotation period T, the
polarization conversion rotary element converts p-polarized lights
of all wavelengths output from the second group into s-polarized,
without changing the polarization directions of p-polarized lights
of all wavelengths output from the first group. The lasers of all
wavelengths in the first group are driven sequentially in a
time-division multiplexing manner to output p-polarized lights of
corresponding wavelengths, therefore, the lights of all wavelengths
output from the first group are input to the first optical imaging
modulator 41 in a time-division multiplexing manner. Color channels
of the image signal input to the first optical imaging modulator 41
correspond to the wavelengths of the lights output from the first
group and input to the first optical imaging modulator 41.
Therefore, the p-polarized lights that correspond to all the
wavelengths output from the first group and are input to the first
optical imaging modulator 41 in a time-division multiplexing manner
are modulated synchronously using the corresponding color channels
of the image signal, thereby obtaining part of the p-polarized
frame that consists of the color channels which correspond to all
the wavelengths output from the first group. Similarly, p-polarized
lights of all wavelengths output from the second group are
converted into s-polarized and then input to the second optical
imaging modulator 42 in a time-division multiplexing manner. Color
channels of the image signal input to the second optical imaging
modulator 42 correspond to the wavelengths of the lights output
from the second group and input to the second optical imaging
modulator 42. Therefore, the s-polarized lights that correspond to
all the wavelengths output from the second group and are input to
the second optical imaging modulator 42 in a time-division
multiplexing manner are modulated synchronously using the
corresponding color channels of the image signal, thereby obtaining
part of the s-polarized frame that consists of the color channels
which correspond to all the wavelengths output from the second
group.
[0080] To sum up, for a rotation period T, in the first time period
t1, part of an s-polarized frame that consists of the color
channels corresponding to all the wavelengths output from the first
group, and part of a p-polarized frame that consists of the color
channels corresponding to all the wavelengths output from the
second group are output; in the second time period t2, part of an
s-polarized frame that consists of the color channels corresponding
to all the wavelengths output from the second group, and part of a
p-polarized frame that consists of the color channels corresponding
to all the wavelengths output from the first group are output. The
rotation period T is less than the visual persistence time,
therefore, for each rotation of the polarization conversion rotary
element, the brain can fuse parts of the s-polarized frame that
consist of the color channels corresponding to all wavelengths in
the s-polarized frame into a complete s-polarized frame; and fuse
parts of the p-polarized frame that consist of the color channels
corresponding to all wavelengths in the p-polarized frame into a
complete p-polarized frame. Moreover, whether it is a p-polarized
or s-polarized frame, at any moment, light output by a laser of any
wavelength is used for the display of a p-polarized or s-polarized
frame. Therefore, compared with the prior art where light output by
a laser is divided simultaneously into a p-polarized component and
an s-polarized component, the stereoscopic imaging device according
to the embodiment of the present invention can make full use of the
total output power of the laser in both p-polarized and s-polarized
lights. Therefore, under the same laser driving power, the
embodiment of the present invention can improve the brightness of
the displayed image.
[0081] As can be seen, in the stereoscopic imaging device according
to the embodiment of the present invention, the lasers in each of
the groups output lights in an alternating manner, but light output
from one group as a whole is continuous. Therefore, compared with
the prior art where all the lasers are illuminated sequentially,
the stereoscopic imaging device according to the embodiment of the
present invention can improve the utilization rate of the light
source.
[0082] Moreover, the stereoscopic imaging device according to the
embodiment of the present invention can simultaneously output
s-polarized and p-polarized images using one projection subsystem.
Compared with the prior art, the embodiment of the present
invention improves the utilization rate of the light source, lowers
manufacturing and processing costs, and reduces the size of the
stereoscopic imaging device. In addition, reducing the number of
optical devices can further lower maintenance expense of the
stereoscopic imaging device, e.g., by reducing the time required
for light path calibration.
[0083] Furthermore, the stereoscopic imaging device provided by an
embodiment of the present invention can make full use of the total
output power of the lasers in both p-polarized and s-polarized
lights. Therefore, under the same laser driving power, the
embodiment of the present invention can improve the brightness of
the displayed image.
[0084] An embodiment of the present invention provides a
stereoscopic display system, including the stereoscopic imaging
device as described above and a projection lens subsystem. The
projection lens subsystem is used to project the output light from
the stereoscopic imaging device. Due to the use of the stereoscopic
imaging device in the embodiments above, as compared with the prior
art, the brightness of the displayed image formed by the
stereoscopic display system is improved significantly, with an even
higher utilization rate of the light source. Moreover, the
stereoscopic display system according to the embodiment of the
present invention can simultaneously output s-polarized and
p-polarized images using one projection subsystem. Compared with
the prior art, the embodiment of the present invention improves the
utilization rate of the light source, lowers manufacturing and
processing costs, and reduces the size of the stereoscopic display
system. In addition, reducing the number of optical devices can
further lower maintenance expense of the stereoscopic display
system, e.g., by reducing the time required for light path
calibration.
[0085] Preferred embodiments of the present invention are described
above. It should be noted that, those skilled in the art can make
various improvements and modifications without deviation from the
principle of the present invention. The improvements and
modifications shall fall within the scope of protection of the
present invention.
* * * * *