U.S. patent application number 13/198080 was filed with the patent office on 2013-02-07 for diffraction-type 3d display element and method for fabricating the same.
The applicant listed for this patent is Yao-Ru Chang, Chien-Yue CHEN, Wen-Chen Hung. Invention is credited to Yao-Ru Chang, Chien-Yue CHEN, Wen-Chen Hung.
Application Number | 20130033752 13/198080 |
Document ID | / |
Family ID | 47626786 |
Filed Date | 2013-02-07 |
United States Patent
Application |
20130033752 |
Kind Code |
A1 |
CHEN; Chien-Yue ; et
al. |
February 7, 2013 |
DIFFRACTION-TYPE 3D DISPLAY ELEMENT AND METHOD FOR FABRICATING THE
SAME
Abstract
A diffraction-type 3D display element is arranged on an image
output face of a 3D display device and comprises a first
diffraction area and a second diffraction area. The first
diffraction area has a plurality of first stepped gratings spaced
apart from each other. The second diffraction area has a plurality
of second stepped gratings spaced apart from each other. The second
diffraction area is adjacent to the first diffraction area and is
arranged symmetrically to the first diffraction area with a central
line being the symmetric axis. The diffraction-type 3D display
element of the invention diffracts the images output by the 3D
display device and projects the diffracted images to two different
viewing areas to provide 3D images for users.
Inventors: |
CHEN; Chien-Yue; (Yunlin
County, TW) ; Hung; Wen-Chen; (Yunlin County, TW)
; Chang; Yao-Ru; (Yunlin County, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CHEN; Chien-Yue
Hung; Wen-Chen
Chang; Yao-Ru |
Yunlin County
Yunlin County
Yunlin County |
|
TW
TW
TW |
|
|
Family ID: |
47626786 |
Appl. No.: |
13/198080 |
Filed: |
August 4, 2011 |
Current U.S.
Class: |
359/569 ;
438/32 |
Current CPC
Class: |
H04N 13/302 20180501;
G02B 5/1857 20130101; G02B 30/26 20200101; G02B 5/1842 20130101;
G02B 26/0808 20130101; G02B 30/27 20200101 |
Class at
Publication: |
359/569 ;
438/32 |
International
Class: |
G02B 5/18 20060101
G02B005/18; H01L 21/027 20060101 H01L021/027 |
Claims
1. A diffraction-type 3D display element, arranged on an image
output face of a 3D display device, comprising a first diffraction
area including a plurality of first stepped gratings spaced apart
from each other and each including a first stepped incline; a
second diffraction area being adjacent to the first diffraction
area and including a plurality of second stepped gratings spaced
apart from each other and each including a second stepped incline,
the second stepped gratings being arranged symmetrically to the
first stepped gratings with a central line being a symmetric
axis.
2. The diffraction-type 3D display element according to claim 1,
wherein the first diffraction area and the second diffraction area
are respectively corresponding to a left-eye image output area and
a right-eye image output area of the 3D display device.
3. The diffraction-type 3D display element according to claim 2,
wherein normals of the first stepped inclines and the second
stepped inclines go far away from the central line.
4. The diffraction-type 3D display element according to claim 1,
wherein there are a plurality of first diffraction areas and a
plurality of second diffraction areas, and wherein the first
diffraction areas and the second diffraction areas are arranged
alternatively.
5. A method for fabricating a diffraction-type 3D display element,
comprising steps: cleaning a substrate; undertaking a first etching
process, wherein the first etching process employs a first mask to
form a plurality of first flattened areas and a plurality of first
recessed areas on the substrate; aligning a second mask, wherein
the second mask is aligned to borders of the first flattened areas
and the first recessed areas; and undertaking a second etching
process, wherein the second etching process employs the second mask
to form second recessed areas on the first flattened areas and the
first recessed areas respectively, and wherein each second recessed
area is formed at a depth smaller than that of the first recessed
area to form a four-step structure.
6. The method for fabricating a diffraction-type 3D display element
according to claim 5, wherein the depth of the second recessed area
is half the depth of the first recessed area.
7. The method for fabricating a diffraction-type 3D display element
according to claim 5 further comprising steps: aligning a third
mask, wherein the third mask is aligned to borders of the first
flattened areas, the first recessed areas and the second recessed
areas; and undertaking a third etching process, wherein the third
mask is used to undertake the third etching process to respectively
form third recessed areas on the first flattened areas, the second
recessed areas in the first flattened areas, the first recessed
areas, and the second recessed areas in the first recessed areas,
and wherein each third recessed area is formed at a depth smaller
than that of the second recessed area to form an eight-step
structure.
8. The method for fabricating a diffraction-type 3D display element
according to claim 7, wherein the depth of the third recessed area
is half the depth of the second recessed area.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a 3D display element,
particularly to a stepped diffraction-type 3D display element.
BACKGROUND OF THE INVENTION
[0002] Multimedia has been evolved from a 2D-image technology to a
3D-image technology. As 3D images provide telepresence and give
users a sense as if the object were really presenting before them,
3D-image technology is very promising in telecommunication and
multimedia entertainment.
[0003] A pair of images of an object captured in different viewing
angles is necessary to construct a 3D image. The pair of images is
mainly taken with single-lens shooting or twin-lens shooting.
[0004] Presenting 3D images with several displays is the simplest
way to realize 3D technology, wherein at least two displays must be
arranged at different locations according to different viewing
angles of the users to present slightly different images. However,
multiple displays occupy too much space and are uneconomic for
users.
[0005] A grating technique uses a parallax barrier to send
different images to different viewing angles of the user. However,
such a technology is likely to generate scrambled images and
results in lower brightness. Besides, inappropriate parallax
barrier design may generate moire fringes and reduce image
quality.
[0006] An R.O.C. patent No. I289685 disclosed an automatic 3D
display device and a method thereof, wherein cylindrical lenses are
arranged before a matrix-type display to project and present 3D
images. However, such a technology has undesirable crosstalk
phenomenon which would result in poor 3D display effect.
SUMMARY OF THE INVENTION
[0007] The primary objective of the present invention is to improve
the 3D display effect of the 3D display technology.
[0008] Another objective of the present invention is to solve the
problem of crosstalk occurring when different 3D images are
respectively projected to the left-eye and right-eye viewing fields
through lenses.
[0009] To achieve the above-mentioned objectives, the present
invention proposes a diffraction-type 3D display element, which is
arranged on an image output face of a 3D display device and
comprises a first diffraction area and a second diffraction area.
The first diffraction area has a plurality of first stepped
gratings spaced apart from each other and each having a first
stepped incline. The second diffraction area is adjacent to the
first diffraction area and has a plurality of second stepped
gratings spaced apart from each other and each having a second
stepped incline. The second stepped gratings are arranged
symmetrically to the first stepped gratings with the central line
being the symmetric axis.
[0010] The present invention also proposes a method for fabricating
a diffraction-type 3D display element, which comprises steps:
[0011] S1: cleaning a substrate;
[0012] S2: undertaking a first etching process, wherein the first
etching process employs a first mask to form a plurality of first
flattened areas and a plurality of first recessed areas on the
substrate;
[0013] S3: aligning a second mask, wherein the second mask is
aligned to the borders of the first flattened areas and first
recessed areas; and
[0014] S4: undertaking a second etching process, wherein the second
etching process employs the second mask to form second recessed
areas on the first flattened areas and the first recessed areas
respectively, and wherein each second recessed area is formed at a
depth smaller than that of the first recessed area to form a
four-step structure.
[0015] In the present invention, the diffraction-type 3D display
element uses gratings to diffract the images outputted by a 3D
display device and present the images in two different viewing
fields, whereby to solve the problem that parallax barrier greatly
reduces brightness in the conventional technology. The stepped
gratings can effectively increase diffraction efficiency and reduce
crosstalk, whereby is increased brightness. Besides, the present
invention uses a semiconductor manufacturing technology to
fabricate four-step stepped gratings in merely two etching
processes and thus outperforms the conventional technology in
mass-production and fabrication cost.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a flowchart of fabricating a diffraction-type 3D
display element according to one embodiment of the present
invention;
[0017] FIGS. 2A-2F are diagrams schematically showing the steps for
fabricating a diffraction-type 3D display element according to one
embodiment of the present invention;
[0018] FIG. 3 is a diagram schematically showing the structure and
projection of a diffraction-type 3D display element according to
one embodiment of the present invention; and
[0019] FIG. 4 is a perspective view schematically showing the
structure of a diffraction-type 3D display element according to one
embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] The technical contents of the present invention are
described in detail in cooperation with drawings below.
[0021] Refer to FIGS. 1-2D. The present invention proposes a method
for fabricating a diffraction-type 3D display element, which
comprises steps:
[0022] Step S1--cleaning a substrate: Use an ultrasonic cleaner
with deionized water to clean a substrate 10 and then dry the
substrate 10.
[0023] Step S2--undertaking a first etching process: As shown in
FIG. 2A and FIG. 2B, use a first mask 21 to undertake an etching
process to form a plurality of first flattened areas 11 and a
plurality of first recessed areas 12 on the substrate 10. It should
be noted that the substrate 10 is coated with a photoresist 22 to
cooperate with the first mask 21 to implement the first etching
process. The first mask 21 has a plurality of first light-shielding
zones 211 to cooperate with the photoresist 22 to define the
dimension and shape of etched areas. The photoresist 22 may be a
positive photoresist or a negative photoresist. The first etching
process only can be undertaken after a plurality of steps including
soft bake, exposure, and development have been completed, which are
the conventional technologies and will not repeat herein.
[0024] Step S3--aligning a second mask: As shown in FIG. 2C and
FIG. 2D, place a second mask 23 over the substrate 10, and align
the second mask 23 to the borders of the first flattened areas 11
and first recessed areas 12. As the first etching process has been
applied to the substrate 10, the second mask 23 must be precisely
aligned to the substrate 10 lest errors occur in the succeeding
steps to reduce light transmittance. Refer to FIG. 2A and FIG. 2C.
The number of the second light-shielding zones 231 of the second
mask 23 is double of that of the first light-shielding zones 211 of
the first mask 21. However, the total area of the second
light-shielding zones 231 is equal to that of the first
light-shielding zones 211. Therefore, the second light-shielding
zones 231 are more densely distributed than the first
light-shielding zones 211 to achieve the desired etching
effect.
[0025] Step S4--undertaking a second etching process: Use the
second mask 23 to undertake a second etching process to form second
recessed areas 13 on the first flattened areas 11 and the first
recessed areas 12 respectively, wherein each second recessed area
13 is formed at a depth smaller than that of the first recessed
area 12 to form a four-step structure. In one embodiment, the
second recessed area 13 is formed at a depth half that of the first
recessed area 12 to form a uniform stepped structure. Similar to
the first etching process, the second etching process is undertaken
after the steps including a photoresist 22a coating, soft bake,
exposure, and development have been completed.
[0026] Step S5--aligning a third mask: As shown in FIG. 2E and FIG.
2F, place a third mask 24 over the substrate 10, and align the
third mask 24 to the borders of the first flattened areas 11, the
first recessed areas 12 and the second recessed areas 13. A
photoresist 22b is coated on the substrate 10 for the succeeding
etching process. The drawings of the present invention only
disclose two etching processes for four-step stepped gratings. In
practice, a third etching process can be used to double the number
of steps. In the third etching process, the third light-shielding
zones 241 of the third mask 24 are even more densely distributed
than the second light-shielding zones 231 of the second mask 23.
Therefore, aligning the third mask 24 is more complicated, more
difficult and more time-consuming.
[0027] Step S6--undertaking a third etching process: Use the third
mask 24 to undertake a third etching process to form third recessed
areas 14 on the first flattened areas 11, the second recessed areas
13 of the first flattened areas 11, the first recessed areas 12,
and the second recessed areas 13 of the first recessed areas 12,
wherein each third recessed area 14 is formed at a depth smaller
than that of the second recessed area 13 to form an eight-step
structure. Preferably, the third recessed area 14 is formed at a
depth half that of the second recessed area 13.
[0028] The present invention also proposes a diffraction-type 3D
display element formed by the steps described above. Refer to FIG.
3 and FIG. 4. The diffraction-type 3D display element 40 of the
present invention is arranged on an image output face 31 of a 3D
display device 30. The diffraction-type 3D display element 40 of
the present invention comprises a first diffraction area 41 and a
second diffraction area 42. The first diffraction area 41 has a
plurality of first stepped gratings 411 spaced apart from each
other. Each first stepped grating 411 has a first stepped incline
412. The second diffraction area 42 is adjacent to the first
diffraction area 41. The second diffraction area 42 has a plurality
of second stepped gratings 421 spaced apart from each other. Each
second stepped grating 421 has a second stepped incline 422. The
second stepped gratings 421 are arranged symmetrically to the first
stepped gratings 411 with a central line 50 being the symmetric
axis. The stepped incline refers to an inclined plane formed by the
stepped structure. Macroscopically, the stepped incline can be
regarded as an inclined plane. Therefore, the stepped inclines are
represented by simple straight-line inclined planes in FIG. 4 to
clearly illustrate the concept of the present invention.
[0029] More specifically, the first diffraction area 41 and the
second diffraction area 42 are respectively corresponding to a
left-eye image output area 32 and a right-eye image output area 33
of the 3D display device 30. After receiving an image from the
left-eye image output area 32, the first diffraction area 41
projects the image to a left-eye viewing field 61. Similarly, the
second diffraction area 42 projects the image from the right-eye
image output area 33 to a right-eye viewing field 62. The left eye
and right eye of the user are respectively located at the left-eye
and right-eye viewing fields 61 and 62 to receive different image
signals. Thereby, the user perceives a 3D image. In one embodiment,
the normals of the first and second stepped inclines 412 and 422 go
far away from the central line 50; thus the first and second
stepped inclines 412 and 422 form a back-to-back structure. As
shown in FIG. 4, each of the left-eye image output area 32 and the
right-eye image output area 33 has three primary-color output
pixels 34, and each primary-color output pixel 34 is corresponding
to four stepped gratings for diffracting and projecting images. It
should be noted that a plurality of first diffraction areas 41 and
a plurality of second diffraction areas 42 are arranged
alternatively to respectively project the image of the 3D display
device 30 from the first diffraction area 41 and the second
diffraction area 42 to the left-eye viewing field 61 and the
right-eye viewing field 62, whereby the images at different
positions of the 3D display device 30 can be projected to the
left-eye viewing field 61 or the right-eye viewing field 62.
[0030] Distinct from the conventional technology using prismatic
lenses or cylindrical lenses to refract images, the present
invention uses diffractive approach to realize 3D display
technology. The diffractive optic element of the present invention
can be fabricated through a micromachining technique, such as a
semiconductor fabrication process or a laser micromachining
process, etc., and features light weight, small volume, easy to
reproduce, and low cost. Compared with the conventional grating,
the stepped grating of the present invention can effectively
increase diffraction efficiency and has fewer crosstalk phenomenon
and higher brightness. The present invention can use merely two
etching processes to form a four-step stepped grating. Therefore,
the present invention has the advantages of mass production, low
cost and high utility.
[0031] The embodiments described above are only to exemplify the
present invention but not to limit the scope of the present
invention. Any equivalent modification or variation according to
the spirit of the present invention is to be also included within
the scope of the present invention.
* * * * *