U.S. patent application number 17/534432 was filed with the patent office on 2022-08-25 for viewing angle switch module and display apparatus.
This patent application is currently assigned to Coretronic Corporation. The applicant listed for this patent is Coretronic Corporation. Invention is credited to Ping-Yen Chen, Yu-Fan Chen, Chung-Yang Fang.
Application Number | 20220269115 17/534432 |
Document ID | / |
Family ID | |
Filed Date | 2022-08-25 |
United States Patent
Application |
20220269115 |
Kind Code |
A1 |
Chen; Yu-Fan ; et
al. |
August 25, 2022 |
VIEWING ANGLE SWITCH MODULE AND DISPLAY APPARATUS
Abstract
A viewing angle switch module includes a viewing angle limiter,
a first electronically controlled viewing angle switch, a second
electronically controlled viewing angle switch, a first polarizer,
and a second polarizer. The viewing angle limiter has an absorption
axis, and an axial direction of the absorption axis is parallel to
a thickness direction of the viewing angle limiter. The viewing
angle limiter, the first electronically controlled viewing angle
switch, the first polarizer, the second electronically controlled
viewing angle switch, and the second polarizer are overlapped. An
axial direction of a first absorption axis of the first polarizer
is parallel to an axial direction of a second absorption axis of
the second polarizer. A display apparatus adopting the viewing
angle switch module is also provided. The viewing angle switch
module and the display apparatus provided by the invention have
better light energy utilization rate.
Inventors: |
Chen; Yu-Fan; (Hsin-Chu,
TW) ; Chen; Ping-Yen; (Hsin-Chu, TW) ; Fang;
Chung-Yang; (Hsin-Chu, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Coretronic Corporation |
Hsin-Chu |
|
TW |
|
|
Assignee: |
Coretronic Corporation
Hsin-Chu
TW
|
Appl. No.: |
17/534432 |
Filed: |
November 23, 2021 |
International
Class: |
G02F 1/13 20060101
G02F001/13; G02F 1/1337 20060101 G02F001/1337; G02F 1/1335 20060101
G02F001/1335; G02F 1/1334 20060101 G02F001/1334 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 24, 2021 |
CN |
202120409196.5 |
Claims
1. A display apparatus, wherein the display apparatus comprises a
backlight module, a viewing angle limiter, a first electronically
controlled viewing angle switch, a second electronically controlled
viewing angle switch, a first polarizer, a second polarizer, and a
display panel, wherein: the viewing angle limiter is overlapped
with the backlight module and has an absorption axis, and an axial
direction of the absorption axis is parallel to a thickness
direction of the viewing angle limiter; the first electronically
controlled viewing angle switch is overlapped with the viewing
angle limiter, and comprises: a first liquid crystal layer; and a
first alignment layer and a second alignment layer, wherein the
first liquid crystal layer is sandwiched between the first
alignment layer and the second alignment layer, and a first
alignment direction of the first alignment layer is substantially
parallel or perpendicular to a second alignment direction of the
second alignment layer; the second electronically controlled
viewing angle switch is overlapped with the first electronically
controlled viewing angle switch, and comprises: a second liquid
crystal layer; and a third alignment layer and a fourth alignment
layer, wherein the second liquid crystal layer is sandwiched
between the third alignment layer and the fourth alignment layer,
and a third alignment direction of the third alignment layer is
parallel to a fourth alignment direction of the fourth alignment
layer; the first polarizer is disposed between the first
electronically controlled viewing angle switch and the second
electronically controlled viewing angle switch, and the first
electronically controlled viewing angle switch is located between
the viewing angle limiter and the first polarizer; the second
polarizer is disposed at one side of the second electronically
controlled viewing angle switch away from the first electronically
controlled viewing angle switch, wherein an axial direction of a
first absorption axis of the first polarizer is parallel to an
axial direction of a second absorption axis of the second
polarizer; and the display panel is overlapped with the backlight
module.
2. The display apparatus of claim 1, wherein an included angle
between the first alignment direction of the first alignment layer
or the second alignment direction of the second alignment layer and
the third alignment direction of the third alignment layer is
between 0 degrees and 45 degrees.
3. The display apparatus of claim 1, wherein the viewing angle
limiter comprises: a polymer substrate; and a plurality of dye
molecules dispersed in the polymer substrate, wherein the plurality
of dye molecules have a first absorption coefficient in the
thickness direction of the viewing angle limiter, the plurality of
dye molecules have a second absorption coefficient perpendicular to
the thickness direction, and a ratio of the first absorption
coefficient to the second absorption coefficient is between 2 and
10000.
4. The display apparatus of claim 1, wherein the second
electronically controlled viewing angle switch is located between
the display panel and the first electronically controlled viewing
angle switch, and the display panel is located between the viewing
angle limiter and the backlight module.
5. The display apparatus of claim 4, wherein the first alignment
direction of the first alignment layer is perpendicular to the
second alignment direction of the second alignment layer, and the
second alignment direction of the second alignment layer is
parallel or perpendicular to the axial direction of the first
absorption axis of the first polarizer.
6. The display apparatus of claim 4, wherein the first alignment
direction of the first alignment layer is parallel to the second
alignment direction of the second alignment layer, and an included
angle between the first alignment direction of the first alignment
layer and the axial direction of the first absorption axis of the
first polarizer is 45 degrees.
7. The display apparatus of claim 1, wherein the display panel is
located between the first electronically controlled viewing angle
switch and the second electronically controlled viewing angle
switch, and the display panel is located between the viewing angle
limiter and the backlight module.
8. The display apparatus of claim 1, wherein the first
electronically controlled viewing angle switch and the viewing
angle limiter are located between the display panel and the
backlight module.
9. The display apparatus of claim 8, wherein the second
electronically controlled viewing angle switch is located between
the display panel and the first electronically controlled viewing
angle switch.
10. The display apparatus of claim 8, wherein the display panel is
located between the first electronically controlled viewing angle
switch and the second electronically controlled viewing angle
switch.
11. The display apparatus of claim 1, further comprising: a
compensation film disposed between the viewing angle limiter and
the first electronically controlled viewing angle switch, wherein
an axial direction of an optical axis of the compensation film is
parallel or perpendicular to the axial direction of the first
absorption axis of the first polarizer.
12. A viewing angle switch module, wherein the viewing angle switch
module comprises a viewing angle limiter, a first electronically
controlled viewing angle switch, a second electronically controlled
viewing angle switch, a first polarizer, and a second polarizer,
wherein: the viewing angle limiter has an absorption axis, and an
axial direction of the absorption axis is parallel to a thickness
direction of the viewing angle limiter; the first electronically
controlled viewing angle switch is overlapped with the viewing
angle limiter, and comprises: a first liquid crystal layer; and a
first alignment layer and a second alignment layer, wherein the
first liquid crystal layer is sandwiched between the first
alignment layer and the second alignment layer, and a first
alignment direction of the first alignment layer is substantially
parallel or perpendicular to a second alignment direction of the
second alignment layer; the second electronically controlled
viewing angle switch is overlapped with the first electronically
controlled viewing angle switch, and comprises: a second liquid
crystal layer; and a third alignment layer and a fourth alignment
layer, wherein the second liquid crystal layer is sandwiched
between the third alignment layer and the fourth alignment layer,
and a third alignment direction of the third alignment layer is
parallel to a fourth alignment direction of the fourth alignment
layer; the first polarizer is disposed between the first
electronically controlled viewing angle switch and the second
electronically controlled viewing angle switch, and the first
electronically controlled viewing angle switch is located between
the viewing angle limiter and the first polarizer; and the second
polarizer is disposed at one side of the second electronically
controlled viewing angle switch away from the first electronically
controlled viewing angle switch, wherein an axial direction of a
first absorption axis of the first polarizer is parallel to an
axial direction of a second absorption axis of the second
polarizer.
13. The viewing angle switch module of claim 12, further comprising
a backlight module, wherein the second electronically controlled
viewing angle switch is located between the backlight module and
the first electronically controlled viewing angle switch.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of China
application serial no. 202120409196.5, filed on Feb. 24, 2021. The
entirety of the above-mentioned patent application is hereby
incorporated by reference herein and made a part of this
specification.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The invention relates to a viewing angle switching
technique, and in particular to a viewing angle switch module and a
display apparatus.
Description of Related Art
[0003] Generally speaking, in order to allow a plurality of viewers
to watch a display apparatus together, the display apparatus
usually has a wide viewing angle display effect. However, in
certain situations or occasions, such as browsing private web pages
or confidential information, or entering passwords in public, the
wide viewing angle display effect is likely to cause confidential
information to be seen by others and cause confidential information
to leak. In order to achieve anti-peep effect, the general approach
is to place a light control film (LCF) in front of the display
panel to filter out large-angle light. Conversely, when there is no
need for anti-peep, the light control film is manually removed from
the front of the display panel. In other words, although this type
of light control film has anti-peep effect, there is still room for
improvement in the convenience of the operation thereof. Therefore,
how to develop a display apparatus with extremely convenient
viewing angle switching and excellent anti-peep effect has become
an important issue for concerned manufacturers.
[0004] The information disclosed in this Background section is only
for enhancement of understanding of the background of the described
technology and therefore it may contain information that does not
form the prior art that is already known to a person of ordinary
skill in the art. Further, the information disclosed in the
Background section does not mean that one or more problems to be
resolved by one or more embodiments of the invention was
acknowledged by a person of ordinary skill in the art.
SUMMARY OF THE INVENTION
[0005] The invention provides a display apparatus that is more
convenient to switch between anti-peep mode and sharing mode, and
also has lower energy consumption.
[0006] The invention provides a viewing angle switch module having
a better light energy utilization rate.
[0007] In order to achieve one or part or all of the above
objectives or other objectives, an embodiment of the invention
provides a display apparatus. The display apparatus includes a
backlight module, a viewing angle limiter, a first electronically
controlled viewing angle switch, a second electronically controlled
viewing angle switch, a first polarizer, a second polarizer, and a
display panel. The viewing angle limiter and the display panel are
overlapped with the backlight module, and the viewing angle limiter
has an absorption axis. An axial direction of the absorption axis
is parallel to a thickness direction of the viewing angle limiter.
The first electronically controlled viewing angle switch is
overlapped with the viewing angle limiter, and includes a first
liquid crystal layer, a first alignment layer, and a second
alignment layer. The first liquid crystal layer is sandwiched
between the first alignment layer and the second alignment layer. A
first alignment direction of the first alignment layer is parallel
or perpendicular to a second alignment direction of the second
alignment layer. The second electronically controlled viewing angle
switch is overlapped with the first electronically controlled
viewing angle switch, and includes a second liquid crystal layer, a
third alignment layer, and a fourth alignment layer. The second
liquid crystal layer is sandwiched between the third alignment
layer and the fourth alignment layer. A third alignment direction
of the third alignment layer is parallel to a fourth alignment
direction of the fourth alignment layer. The first polarizer is
disposed between the first electronically controlled viewing angle
switch and the second electronically controlled viewing angle
switch. The first electronically controlled viewing angle switch is
located between the viewing angle limiter and the first polarizer.
The second polarizer is disposed at one side of the second
electronically controlled viewing angle switch away from the first
electronically controlled viewing angle switch. An axial direction
of a first absorption axis of the first polarizer is parallel to an
axial direction of a second absorption axis of the second
polarizer.
[0008] In order to achieve one or part or all of the above
objectives or other objectives, an embodiment of the invention
provides a viewing angle switch module. The viewing angle switch
module includes a viewing angle limiter, a first electronically
controlled viewing angle switch, a second electronically controlled
viewing angle switch, a first polarizer, and a second polarizer.
The viewing angle limiter has an absorption axis, and an axial
direction of the absorption axis is parallel to a thickness
direction of the viewing angle limiter. The first electronically
controlled viewing angle switch is overlapped with the viewing
angle limiter, and includes a first liquid crystal layer, a first
alignment layer, and a second alignment layer. The first liquid
crystal layer is sandwiched between the first alignment layer and
the second alignment layer. A first alignment direction of the
first alignment layer is parallel or perpendicular to a second
alignment direction of the second alignment layer. The second
electronically controlled viewing angle switch is overlapped with
the first electronically controlled viewing angle switch, and
includes a second liquid crystal layer, a third alignment layer,
and a fourth alignment layer. The second liquid crystal layer is
sandwiched between the third alignment layer and the fourth
alignment layer. A third alignment direction of the third alignment
layer is parallel to a fourth alignment direction of the fourth
alignment layer. The first polarizer is disposed between the first
electronically controlled viewing angle switch and the second
electronically controlled viewing angle switch. The first
electronically controlled viewing angle switch is located between
the viewing angle limiter and the first polarizer. The second
polarizer is disposed at one side of the second electronically
controlled viewing angle switch away from the first electronically
controlled viewing angle switch. An axial direction of a first
absorption axis of the first polarizer is parallel to an axial
direction of a second absorption axis of the second polarizer.
[0009] Based on the above, in the viewing angle switch module and
the display apparatus of an embodiment of the invention, via the
absorption characteristics of the viewing angle limiter in a
specific direction and the cooperation with the two electronically
controlled viewing angle switches, the light energy utilization
rate of the viewing angle switch module may be increased, thereby
reducing the operating energy consumption of the display apparatus.
At the same time, the anti-peep effect of the display apparatus
under a large viewing angle may also be improved. Moreover, the
electronically controllable features of the two electronically
controlled viewing angle switches make it extremely convenient for
the display apparatus to switch between anti-peep mode and sharing
mode.
[0010] Other objectives, features and advantages of the invention
will be further understood from the further technological features
disclosed by the embodiments of the invention wherein there are
shown and described preferred embodiments of this invention, simply
by way of illustration of modes best suited to carry out the
invention.
[0011] In order to make the above features and advantages of the
invention better understood, embodiments are specifically provided
below with reference to figures for detailed description as
follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The accompanying drawings are included to provide a further
understanding of the invention, and are incorporated in and
constitute a part of this specification. The drawings illustrate
embodiments of the invention and, together with the description,
serve to explain the principles of the invention.
[0013] FIG. 1A and FIG. 1B are schematic cross-sectional views of
the display apparatus of the first embodiment of the invention
operated in sharing mode and anti-peep mode.
[0014] FIG. 2 is a schematic diagram of a portion of the film
layers of the display apparatus of FIG. 1A.
[0015] FIG. 3A is a transmittance distribution diagram of the
display apparatus of FIG. 1A operated in sharing mode.
[0016] FIG. 3B is a transmittance distribution diagram of the
display apparatus of FIG. 1B operated in anti-peep mode.
[0017] FIG. 4 is a graph of viewing angle versus transmittance of
the second electronically controlled viewing angle switch of FIG.
1A.
[0018] FIG. 5A and FIG. 5B are schematic side views of backlight
modules of some other embodiments of the invention.
[0019] FIG. 6A is a transmittance distribution diagram of the
display apparatus of FIG. 1B adopting the backlight module of FIG.
5A and operated in anti-peep mode.
[0020] FIG. 6B is a transmittance distribution diagram of the
display apparatus of FIG. 1A adopting the backlight module of FIG.
5A and operated in sharing mode.
[0021] FIG. 7 is a schematic diagram of a portion of the film
layers of the display apparatus of the second embodiment of the
invention.
[0022] FIG. 8 is a transmittance distribution diagram of the
display apparatus of FIG. 7 operated in anti-peep mode.
[0023] FIG. 9 is a schematic diagram of a portion of the film
layers of the display apparatus of the third embodiment of the
invention.
[0024] FIG. 10A and FIG. 10B are schematic cross-sectional views of
the display apparatus of the fourth embodiment of the invention
operated in anti-peep mode and sharing mode.
[0025] FIG. 11 is a schematic diagram of a portion of the film
layers of the display apparatus of FIG. 10A.
[0026] FIG. 12 is a schematic cross-sectional view of the display
apparatus of the fifth embodiment of the invention.
[0027] FIG. 13 is a schematic diagram of a portion of the film
layers of the display apparatus of FIG. 12.
[0028] FIG. 14 is a schematic diagram of a portion of the film
layers of the display apparatus of the sixth embodiment of the
invention.
[0029] FIG. 15 is a schematic cross-sectional view of the display
apparatus of the seventh embodiment of the invention.
[0030] FIG. 16 is a schematic diagram of a portion of the film
layers of the display apparatus of FIG. 15.
[0031] FIG. 17 is a schematic cross-sectional view of the display
apparatus of the eighth embodiment of the invention.
[0032] FIG. 18 is a schematic diagram of a portion of the film
layers of the display apparatus of FIG. 17.
[0033] FIG. 19 is a schematic cross-sectional view of the display
apparatus of the ninth embodiment of the invention.
[0034] FIG. 20 is a schematic diagram of a portion of the film
layers of the display apparatus of FIG. 19.
DESCRIPTION OF THE EMBODIMENTS
[0035] In the following detailed description of the preferred
embodiments, reference is made to the accompanying drawings which
form a part hereof, and in which are shown by way of illustration
specific embodiments in which the invention may be practiced. In
this regard, directional terminology, such as "top," "bottom,"
"front," "back," etc., is used with reference to the orientation of
the Figure(s) being described. The components of the invention may
be positioned in a number of different orientations. As such, the
directional terminology is used for purposes of illustration and is
in no way limiting. On the other hand, the drawings are only
schematic and the sizes of components may be exaggerated for
clarity. It is to be understood that other embodiments may be
utilized and structural changes may be made without departing from
the scope of the invention. Also, it is to be understood that the
phraseology and terminology used herein are for the purpose of
description and should not be regarded as limiting. The use of
"including," "comprising," or "having" and variations thereof
herein is meant to encompass the items listed thereafter and
equivalents thereof as well as additional items. Unless limited
otherwise, the terms "connected," "coupled," and "mounted" and
variations thereof herein are used broadly and encompass direct and
indirect connections, couplings, and mountings. Similarly, the
terms "facing," "faces" and variations thereof herein are used
broadly and encompass direct and indirect facing, and "adjacent to"
and variations thereof herein are used broadly and encompass
directly and indirectly "adjacent to". Therefore, the description
of "A" component facing "B" component herein may contain the
situations that "A" component directly faces "B" component or one
or more additional components are between "A" component and "B"
component. Also, the description of "A" component "adjacent to" "B"
component herein may contain the situations that "A" component is
directly "adjacent to" "B" component or one or more additional
components are between "A" component and "B" component.
Accordingly, the drawings and descriptions will be regarded as
illustrative in nature and not as restrictive.
[0036] FIG. 1A and FIG. 1B are schematic cross-sectional views of
the display apparatus of the first embodiment of the invention
operated in sharing mode and anti-peep mode. FIG. 2 is a schematic
diagram of a portion of the film layers of the display apparatus of
FIG. 1A. FIG. 3A is a transmittance distribution diagram of the
display apparatus of FIG. 1A operated in sharing mode. FIG. 3B is a
transmittance distribution diagram of the display apparatus of FIG.
1B operated in anti-peep mode. FIG. 4 is a graph of viewing angle
versus transmittance of the second electronically controlled
viewing angle switch of FIG. 1A.
[0037] Please refer to FIG. 1A, FIG. 1B, and FIG. 2, a display
apparatus 10 includes a backlight module BLU, a display panel DP,
and a viewing angle switch module 50. The viewing angle switch
module 50 is overlapped with the backlight module BLU, and includes
a viewing angle limiter 100, a first electronically controlled
viewing angle switch 210, a second electronically controlled
viewing angle switch 220, a first polarizer 310, and a second
polarizer 320. In the embodiment, the display panel DP is
overlapped with the backlight module and disposed between the
backlight module BLU and the viewing angle switch module 50. For
example, the first electronically controlled viewing angle switch
210 and the second electronically controlled viewing angle switch
220 are disposed between the viewing angle limiter 100 and the
display panel DP, the display panel DP is disposed between the
second electronically controlled viewing angle switch 220 and the
backlight module BLU, and the first electronically controlled
viewing angle switch 210 is disposed between the viewing angle
limiter 100 and the second electronically controlled viewing angle
switch 220, but are not limited thereto. Specifically, the second
electronically controlled viewing angle switch 220 is, for example,
located between the display panel DP and the first electronically
controlled viewing angle switch 210, and the display panel DP is,
for example, located between the viewing angle limiter 100 and the
backlight module BLU.
[0038] The viewing angle limiter 100 is overlapped with the
backlight module BLU, the viewing angle limiter 100 has an
absorption axis AX, and an axial direction of the absorption axis
AX is parallel to the thickness direction (for example, a direction
Z) of the viewing angle limiter 100. Specifically, the viewing
angle limiter 100 includes a polymer substrate PS and a plurality
of dye molecules DM. The dye molecules DM are dispersed in the
polymer substrate PS. In the embodiment, the polymer substrate PS
has a substrate surface PSa, and the axial direction of the
absorption axis AX of the dye molecules DM (i.e., the axial
direction of the absorption axis AX of the viewing angle limiter
100) may be perpendicular to the substrate surface PSa of the
polymer substrate PS (the axial direction of the absorption axis AX
is, for example, parallel to the stacking direction of the viewing
angle limiter 100 and the display panel DP, such as the direction
Z). It should be mentioned that, the dye molecules DM have a first
absorption coefficient in the thickness direction of the viewing
angle limiter 100 (that is, the normal direction of the substrate
surface PSa, for example, the direction Z), and there is a second
absorption coefficient perpendicular to the thickness direction
(for example, a direction X or a direction Y), and the first
absorption coefficient is different from the second absorption
coefficient.
[0039] In the embodiment, the first absorption coefficient of the
dye molecules DM is significantly greater than the second
absorption coefficient, and the ratio of the first absorption
coefficient to the second absorption coefficient is between 2 and
10000. Accordingly, the light filter effect of the viewing angle
limiter 100 in the side viewing angle and the light transmittance
in the viewing angle range may be effectively increased, thereby
improving the anti-peep performance of the display apparatus 10 and
the overall brightness of light from other angles of view after
being emitted from the display apparatus 10. In a preferred
embodiment, the ratio of the first absorption coefficient to the
second absorption coefficient of the plurality of dye molecules DM
may be between 100 and 1000 (or greater than 100). In another
preferred embodiment, the ratio of the first absorption coefficient
to the second absorption coefficient of the plurality of dye
molecules DM may also be between 500 and 1000.
[0040] For example, the material of the dye molecules DM includes
an azo-type compound or an anthraquinone-type compound, and the
material of the polymer substrate PS includes a liquid crystal
polymer. The liquid crystal polymer here may be formed by
subjecting a liquid crystal mixed material layer to ultraviolet
light irradiation, wherein the liquid crystal mixed material layer
includes a plurality of liquid crystal molecules LC, a reactive
mesogen with a specific doping concentration, and a photoinitiator.
However, the invention is not limited thereto. According to other
embodiments, the liquid crystal polymer may also be a material
having a chemical functional group similar to a dichroic dye
structure. That is, in the embodiment, the viewing angle limiter
may not have the dye molecules DM.
[0041] In the embodiment, the viewing angle limiter 100 may also
optionally include a protective layer 101 and a protective layer
102 respectively disposed on the substrate surface PSa and a
substrate surface PSb at the opposite sides of the polymer
substrate PS. The protective layer 101 and the protective layer 102
may be hard coat films, low-reflection films, anti-reflection
films, anti-smudge films, anti-fingerprint films, anti-glare films,
anti-scratch films, or a composite film layer of the above, but is
not limited thereto.
[0042] The first electronically controlled viewing angle switch 210
is overlapped with the viewing angle limiter 100, and may
optionally include a first substrate 211, a second substrate 212, a
first electrode E1, a second electrode E2, and a first liquid
crystal layer LCL1. The first electrode E1 and the second electrode
E2 disposed oppositely are respectively disposed on the first
substrate 211 and the second substrate 212. The first electrode E1
and the second electrode E2 are, for example, surface electrodes,
but are not limited thereto. The first liquid crystal layer LCL1 is
disposed between the first electrode E1 and the second electrode
E2, and includes a plurality of liquid crystal molecules LC1. The
material of the first substrate 211 and the second substrate 212
may include glass, quartz, organic polymer, or other suitable
transparent materials. The first electrode E1 and the second
electrode E2 are, for example, light-transmissive electrodes, and
the material of the light-transmissive electrodes includes indium
tin oxide, indium zinc oxide, aluminum tin oxide, aluminum zinc
oxide, or other suitable oxides, a hollowed metal layer (metal mesh
or wire grid), carbon nanotube, Ag nano-wire, graphene, or stacked
layers of at least two of the above.
[0043] In order to allow the optical axis of the plurality of
liquid crystal molecules LC1 of the first liquid crystal layer LCL1
to be arranged in a specific direction or in a specific
distribution pattern without an external electric field (that is,
when no voltage is applied between the two electrodes), the first
electronically controlled viewing angle switch 210 further includes
a first alignment layer AL1 and a second alignment layer AL2. The
first alignment layer AL1 is disposed between the first electrode
E1 and the first liquid crystal layer LCL1, the second alignment
layer AL2 is disposed between the second electrode E2 and the first
liquid crystal layer LCL1, and the first liquid crystal layer LCL1
is sandwiched between the first alignment layer AL1 and the second
alignment layer AL2. In the embodiment, a first alignment direction
AD1 of the first alignment layer AL1 is parallel to the direction
X, and a second alignment direction AD2 of the second alignment
layer AL2 is parallel to the direction Y. That is, the first
alignment direction AD1 of the first alignment layer AL1 is
substantially perpendicular to the second alignment direction AD2
of the second alignment layer AL2, but is not limited thereto. In
other embodiments, the first alignment direction AD1 of the first
alignment layer AL1 may be substantially parallel or anti-parallel
to the second alignment direction AD2 of the second alignment layer
AL2. More specifically, the liquid crystal molecules LC1 of the
first liquid crystal layer LCL1 of the embodiment are arranged
between the first alignment layer AL1 and the second alignment
layer AL2 by means of twist deformation without an external
electric field (as shown in FIG. 1A).
[0044] Similarly, the second electronically controlled viewing
angle switch 220 is overlapped with the first electronically
controlled viewing angle switch 210, and may optionally include a
third substrate 221, a fourth substrate 222, a third electrode E3,
a fourth electrode E4, and a second liquid crystal layer LCL2. The
third electrode E3 and the fourth electrode E4 disposed oppositely
are respectively disposed on the third substrate 221 and the fourth
substrate 222. The third electrode E3 and the fourth electrode E4
are, for example, surface electrodes, but are not limited thereto.
The second liquid crystal layer LCL2 is disposed between the third
electrode E3 and the fourth electrode E4, and includes a plurality
of liquid crystal molecules LC2. The material of the third
substrate 221 and the fourth substrate 222 may include glass,
quartz, organic polymer, or other suitable transparent materials.
The third electrode E3 and the fourth electrode E4 are, for
example, light-transmissive electrodes, and the material of the
light-transmissive electrodes includes indium tin oxide, indium
zinc oxide, aluminum tin oxide, aluminum zinc oxide, or other
suitable oxides, a hollowed metal layer (metal mesh or wire grid),
carbon nanotube, Ag nano-wire, graphene, or stacked layers of at
least two of the above.
[0045] In order to allow the optical axis of the plurality of
liquid crystal molecules LC2 of the second liquid crystal layer
LCL2 to be arranged in a specific direction or in a specific
distribution pattern without an external electric field (that is,
when no voltage is applied between the two electrodes), the second
electronically controlled viewing angle switch 220 further includes
a third alignment layer AL3 and a fourth alignment layer AL4. The
third alignment layer AL3 is disposed between the third electrode
E3 and the second liquid crystal layer LCL2, the fourth alignment
layer AL4 is disposed between the fourth electrode E4 and the
second liquid crystal layer LCL2, and the second liquid crystal
layer LCL2 is sandwiched between the third alignment layer AL3 and
the fourth alignment layer AL4. In the embodiment, a third
alignment direction AD3 (for example, the direction Y) of the third
alignment layer AL3 is parallel or anti-parallel to a fourth
alignment direction AD4 of the fourth alignment layer AL4. In other
words, the liquid crystal molecules LC2 of the second liquid
crystal layer LCL2 are substantially arranged between the third
alignment layer AL3 and the fourth alignment layer AL4 in a manner
parallel to direction Y.
[0046] It should be mentioned that, the included angle between the
first alignment direction AD1 of the first alignment layer AL1 or
the second alignment direction AD2 of the second alignment layer
AL2 of the first electronically controlled viewing angle switch 210
(one of the first alignment direction AD1 and the second alignment
direction AD2) and the third alignment direction AD3 of the third
alignment layer AL3 of the second electronically controlled viewing
angle switch 220 (or the fourth alignment direction AD4 of the
fourth alignment layer AL4) is between 0 degrees and 45 degrees.
For example, in the embodiment, the second alignment direction AD2
of the second alignment layer AL2 of the first electronically
controlled viewing angle switch 210 may be parallel to the third
alignment direction AD3 of the third alignment layer AL3 of the
second electronically controlled viewing angle switch 220 (or
anti-parallel to the fourth alignment direction AD4 of the fourth
alignment layer AL4), but is not limited thereto.
[0047] Moreover, the first polarizer 310 and the second polarizer
320 of the viewing angle switch module 50 are respectively disposed
at opposite sides of the second electronically controlled viewing
angle switch 220. More specifically, the first polarizer 310 is
disposed between the first electronically controlled viewing angle
switch 210 and the second electronically controlled viewing angle
switch 220, and the first electronically controlled viewing angle
switch 210 is located between the viewing angle limiter 100 and the
first polarizer 310, and the second polarizer 320 is disposed at
one side of the second electronically controlled viewing angle
switch 220 away from the first electronically controlled viewing
angle switch 210. In the embodiment, the first polarizer 310 and
the second polarizer 320 are, for example, respectively attached to
two opposite sides of the second electronically controlled viewing
angle switch 220, but are not limited thereto. It should be
mentioned that, the axial direction of a first absorption axis AX1
of the first polarizer 310 is parallel to the axial direction of a
second absorption axis AX2 of the second polarizer 320. In the
embodiment, the axial direction of the first absorption axis AX1 of
the first polarizer 310 and the axial direction of the second
absorption axis AX2 of the second polarizer 320 may be parallel to
the second alignment direction AD2 of the second alignment layer
AL2 of the first electronically controlled viewing angle switch 210
(that is, parallel to the third alignment direction AD3 of the
third alignment layer AL3 and the fourth alignment direction AD4 of
the fourth alignment layer AL4 of the second electronically
controlled viewing angle switch 220), but are not limited
thereto.
[0048] The display panel DP includes a liquid crystal cell LCC and
a third polarizer 330, and the third polarizer 330 is disposed at
one side of the liquid crystal cell LCC away from the second
electronically controlled viewing angle switch 220. The axial
direction of a third absorption axis AX3 of the third polarizer 330
is perpendicular to the axial direction of the first absorption
axis AX1 of the first polarizer 310 and the axial direction of the
second absorption axis AX2 of the second polarizer 320. The liquid
crystal cell LCC is suitable for rotating the polarization
direction of the passing light beam by 90 degrees, for example. It
should be mentioned that, unlike ordinary display panels, which
mostly have upper and lower polarizers, since the second polarizer
320 of the embodiment is disposed (for example, attached) between
the second electronically controlled viewing angle switch 220 and
the display panel DP, the display panel DP only has a lower
polarizer (that is, the third polarizer 330), and the upper
polarizer of the display panel DP is replaced by the second
polarizer 320 on the second electronically controlled viewing angle
switch 220. In other words, the display panel DP and the second
electronically controlled viewing angle switch 220 of the
embodiment share the second polarizer 320 (common part). It should
be understood that, in another embodiment, the second polarizer 320
may also be disposed at the upper surface of the display panel DP
as a commonly used upper polarizer for the display panel DP.
However, the invention is not limited thereto. In yet another
embodiment, the two opposite surfaces of the display panel DP and
the second electronically controlled viewing angle switch 220 may
be respectively provided with two polarizers with the same
absorption axis. That is, the display panel DP and the second
electronically controlled viewing angle switch 220 may also not
share a polarizer.
[0049] The following exemplarily describes the anti-peep mode and
the sharing mode of the display apparatus 10 (for example, the
display apparatus 10 is used to display a white screen, that is, an
example of light-transmissive mode). Referring further to FIG. 1A
and FIG. 1B, first, non-polarized light beams from the backlight
module BLU, for example, a light beam LB1 emitted in the forward
direction and two light beams LB2 and LB3 emitted obliquely, have a
first linear polarization P1 after passing through the display
panel DP. For example, the orthogonal projection of the
polarization direction of the first linear polarization P1 on the
third polarizer 330 may be parallel to the axial direction of the
third absorption axis AX3 (after the light beam passes through the
third polarizer 330, the polarization direction is rotated 90
degrees by the liquid crystal cell LCC), but is not limited
thereto. In other embodiments, the light beam passing through the
display panel DP may also have elliptical polarization, and the
long axis of the elliptical polarization is substantially
perpendicular to the second absorption axis AX2 of the second
polarizer 320.
[0050] In the embodiment, when the display apparatus 10 is operated
in sharing mode (as shown in FIG. 1A), both the first
electronically controlled viewing angle switch 210 and the second
electronically controlled viewing angle switch 220 are not enabled.
That is, a voltage is not applied between the first electrode E1
and the second electrode E2 of the first electronically controlled
viewing angle switch 210, and a voltage is not applied between the
third electrode E3 and the fourth electrode E4 of the second
electronically controlled viewing angle switch 220.
[0051] When an electric field is not applied to the second liquid
crystal layer LCL2 of the second electronically controlled viewing
angle switch 220, the plurality of liquid crystal molecules LC2 are
arranged in parallel, for example, in a manner parallel to the
axial direction of the second absorption axis AX2 of the second
polarizer 320. Therefore, after the light beams (such as the light
beam LB1 to the light beam LB3) from the display panel DP pass
through the second polarizer 320, the second electrically
controlled viewing angle switch 220, and the first polarizer 310 in
order, the polarization states thereof and the intensity of the
polarized electric field are not changed. Conversely, when an
electric field is not applied to the first liquid crystal layer
LCL1 of the first electronically controlled viewing angle switch
210, the plurality of liquid crystal molecules LC1 are arranged in
a twisted deformation manner (for example, twisted 90 degrees).
Therefore, after the light beam from the second electronically
controlled viewing angle switch 220 passes through the first
electronically controlled viewing angle switch 210, the
polarization state thereof is changed from the first linear
polarization P1 to a second linear polarization P2. The
polarization direction of the first linear polarization P1 is, for
example, perpendicular to the polarization direction of the second
linear polarization P2.
[0052] When the light beam from the first electronically controlled
viewing angle switch 210 enters the viewing angle limiter 100, the
electric field polarization direction thereof is perpendicular to
the axial direction of the absorption axis AX of the dye molecules
DM. Therefore, both the light beam LB2 and the light beam LB3
incident obliquely or the light beam LB1 incident normally may pass
through the viewing angle limiter 100 without substantial optical
energy loss. In other words, the user may operate the display
apparatus 10 in the direction X with a larger viewing angle range
(as shown in FIG. 3A) to achieve the effect of display image
sharing.
[0053] Furthermore, when the display apparatus 10 is operated in
anti-peep mode (as shown in FIG. 1B), both the first electronically
controlled viewing angle switch 210 and the second electronically
controlled viewing angle switch 220 are enabled. That is, a voltage
is applied between the first electrode E1 and the second electrode
E2 of the first electronically controlled viewing angle switch 210,
and a voltage is applied between the third electrode E3 and the
fourth electrode E4 of the second electronically controlled viewing
angle switch 220.
[0054] When an electric field is applied to the second liquid
crystal layer LCL2 of the second electronically controlled viewing
angle switch 220, a portion of the liquid crystal molecules LC2 is
arranged obliquely on the YZ plane (for example, the included angle
between the optical axis of the liquid crystal molecules LC2 and
the film surface of the third alignment layer AL3 is greater than
45 degrees and less than or equal to 90 degrees). Therefore, after
a light beam LB2' and a light beam LB3' incident obliquely pass
through the second polarizer 320, the second electrically
controlled viewing angle switch 220, and the first polarizer 310 in
order, the polarization state thereof is changed into a first
linear polarization P1' in which the intensity of the polarized
electric field is weakened. After the light beam LB1' incident
normally passes through the second polarizer 320, the second
electronically controlled viewing angle switch 220, and the first
polarizer 310 in order, the polarization state thereof and the
intensity of the polarized electric field remain unchanged. That
is, the light beam LB1' still has the first linear polarization P1
(i.e., the intensity of the polarized electric field of the first
linear polarization P1' is less than the intensity of the polarized
electric field of the first linear polarization P1).
[0055] In particular, the polarized electric field intensities of
the polarization states of light beams incident on the second
polarizer 320 at different oblique angles are weakened to different
degrees. Specifically, via the above configuration of the second
electronically controlled viewing angle switch 220 (that is, the
relative relationship between the alignment direction of the second
liquid crystal layer LCL2, the axial direction of the first
absorption axis AX1 of the first polarizer 310, and the axial
direction of the second absorption axis AX2 of the second polarizer
320), the second electronically controlled viewing angle switch 220
may have a cutoff effect (for example, the transmittance is less
than 10%) with a specific viewing angle range. For example, when
the total phase retardation of the second liquid crystal layer LCL2
is 2.24 microns, the second electronically controlled viewing angle
switch 220 may have a cutoff effect with a viewing angle range of
24 degrees to 30 degrees (as shown in FIG. 4). When the viewing
angle is larger (for example, greater than 35 degrees), the cutoff
effect of the second electronically controlled viewing angle switch
220 is significantly worse. That is, when the display apparatus 10
is operated in anti-peep mode, the second electronically controlled
viewing angle switch 220 is only used to achieve an anti-peep
effect (or a cutoff effect) in a small viewing angle range (for
example, a viewing angle range of 24 degrees to 30 degrees).
[0056] More specifically, when an electric field is applied to the
first liquid crystal layer LCL1 of the first electronically
controlled viewing angle switch 210, the plurality of liquid
crystal molecules LC1 are substantially arranged in a manner
perpendicular to the film surface of the first alignment layer AL1.
Therefore, after the light beam from the second electronically
controlled viewing angle switch 220 passes through the first
electronically controlled viewing angle switch 210, the
polarization state thereof is not substantially changed. Therefore,
the light beam LB1' normally incident on the viewing angle limiter
100 is not absorbed because the electric field polarization
direction thereof is perpendicular to the axial direction of the
absorption axis AX of the dye molecules DM. The light components of
the light beam LB2' and the light beam LB3' incident obliquely to
the viewing angle limiter 100 and with an electric field
polarization direction parallel to the absorption axis AX of the
dye molecules DM are absorbed by the dye molecules DM. Due to the
different optical path lengths of the light beams with different
incident angles in the viewing angle limiter 100 and the different
included angles between the polarization directions of the electric
fields of the light beams and the absorption axis AX, the degree of
absorption of the light component of the first linear polarization
P1' is also different. For example: the greater the incident angle
of the light, the more the light component of the first linear
polarization P1' is absorbed by the dye molecules DM. Therefore,
the viewing angle limiter 100 may have a light filter effect with a
large viewing angle. It should be understood that the light filter
effect of the viewing angle limiter 100 at the side viewing angle
may also be adjusted by the addition concentration of the dye
molecules DM, the absorption coefficient, or the change of the film
thickness of the polymer substrate PS.
[0057] The light filter effect of the viewing angle limiter 100 in
a large viewing angle and the cutoff effect of the second
electronically controlled viewing angle switch 220 in a small
viewing angle range allow the user to operate the display apparatus
10 in the direction X with a smaller viewing angle range (as shown
in FIG. 3B), so as to achieve an anti-peep effect.
[0058] In the embodiment, the backlight module BLU may be a general
backlight module, for example, including a light guide plate, a
light-emitting element, a diffusion sheet, a prism sheet, and a
reflective sheet, wherein the light guide plate has a
light-incident surface, and a light-emitting surface and a bottom
surface connected to the light-incident surface and opposite to
each other. The light-emitting element is disposed at one side of
the light-incident surface of the light guide plate, the diffusion
sheet is disposed at one side of the light-emitting surface of the
light guide plate, and the reflective sheet is disposed at one side
of the bottom surface of the light guide plate. However, the
invention is not limited thereto. In other embodiments, in order to
achieve better anti-peep effect and sharing effect, the display
apparatus may adopt a light-type switchable backlight module.
[0059] FIG. 5A and FIG. 5B are schematic side views of backlight
modules of some other embodiments of the invention. FIG. 6A is a
transmittance distribution diagram of the display apparatus of FIG.
1B adopting the backlight module of FIG. 5A and operated in
anti-peep mode. FIG. 6B is a transmittance distribution diagram of
the display apparatus of FIG. 1A adopting the backlight module of
FIG. 5A and operated in sharing mode. Referring to FIG. 1A, FIG.
1B, FIG. 5A, FIG. 6A, and FIG. 6B, the display apparatus of FIG. 5A
differs from the display apparatus 10 of FIG. 1A only in: the
backlight module BLU of FIG. 1A may be replaced by a backlight
module BLU-A shown in FIG. 5A. The backlight module BLU-A includes
a first light guide plate LGP1, a second light guide plate LGP2, a
plurality of first light-emitting elements LED1, a plurality of
second light-emitting elements LED2, a first prism sheet 410, a
second prism sheet 420, a third prism sheet 430, and a diffusion
sheet DF. The first light guide plate LGP1 has two light-incident
surfaces LGP1s1 and LGP1s2 opposite to each other, and a
light-emitting surface LGP1s3 and a bottom surface LGP1s4 connected
to the two light-incident surfaces LGP1s1 and LGP1s2 and opposite
to each other, and the first light guide plate LGP1 is, for
example, an edge-type backlight light guide plate. The plurality of
first light-emitting elements LED1 are respectively provided at
both sides of the two light incident surfaces LGP1s1 and LGP1s2 of
the first light guide plate LGP1, and the first prism sheet 410 is
provided at one side of the light-emitting surface LGP1s3 thereof.
A plurality of prism structures 410P of the first prism sheet 410
are located between a substrate 411 and the first light guide plate
LGP1, that is, the first prism sheet 410 is a reverse prism
sheet.
[0060] One side of the bottom surface LGP1s4 of the first light
guide plate LGP1 is provided with the second light guide plate
LGP2, and the second light guide plate LGP2 has a light incident
surface LGP2s1 and a light-emitting surface LGP2s2 opposite to each
other, wherein the light-emitting surface LGP2s2 faces the bottom
surface LGP1s4 of the first light guide plate LGP1, and the second
light guide plate LGP2 is, for example, a light guide plate of a
direct-type backlight. The plurality of second light-emitting
elements LED2 are disposed at one side of the light incident
surface LGP2s1 of the second light guide plate LGP2. The second
prism sheet 420, the third prism sheet 430, and the diffusion sheet
DF are provided between the light-emitting surface LGP2s2 of the
second light guide plate LGP2 and the bottom surface LGP1s4 of the
first light guide plate LGP1, wherein the diffusion sheet DF is
disposed closer to the position of the second light guide plate
LGP2. Here, a plurality of prism structures 420P of the second
prism sheet 420 and a plurality of prism structures 430P of the
third prism sheet 430 are disposed opposite to each other. In other
words, the prism structures 420P and the prism structures 430P are
disposed between a substrate 421 of the second prism sheet 420 and
a substrate 431 of the third prism sheet 430. That is, the second
prism sheet 420 and the third prism sheet 430 are, for example, a
reverse prism sheet and a prism sheet, but are not limited thereto.
In other embodiments, referring to FIG. 5B at the same time, the
difference between a backlight module BLU-B of FIG. 5B and the
backlight module BLU-A of FIG. 5A is: the prism structures 420P of
the second prism sheet 420 and the prism structures 430P of the
third prism sheet 430 of the backlight module BLU-B may also be
disposed opposite to each other; that is, the substrate 421 of the
second prism sheet 420 and the substrate 431 of the third prism
sheet 430 may also be located between the prism structures 420P and
the prism structures 430P.
[0061] In particular, the backlight module BLU-A (or the backlight
module BLU-B) may switch the light type in correspondence to the
operation mode of the display apparatus. For example, when the
display apparatus is operated in anti-peep mode, only the first
light-emitting elements LED1 are enabled to emit an illumination
beam, and the optical components (that is, the second light guide
plate LGP2 and the second light-emitting elements LED2) located at
one side of the bottom surface LGP1s4 of the first light guide
plate LGP1 do not function. At this time, the light beam emitted by
the backlight module BLU-A (or the backlight module BLU-B) has a
narrower light pattern to help further improve the anti-peep effect
of the display apparatus (as shown in FIG. 6A). When the display
apparatus is operated in sharing mode, only the second
light-emitting elements LED2 are enabled (or the first
light-emitting elements LED1 and the second light-emitting elements
LED2 are simultaneously enabled) to emit an illumination beam. At
this time, the light beam emitted by the backlight module BLU-A (or
the backlight module BLU-B) has a wider light pattern to help
further increase the viewing angle range of the display apparatus
in the direction X (as shown in FIG. 6B).
[0062] Some other embodiments are provided below to describe the
disclosure in detail, wherein the same members are marked with the
same reference numerals, and the description of the same technical
content is omitted. For the omitted portions, please refer to the
above embodiments, which are not repeated herein.
[0063] FIG. 7 is a schematic diagram of a portion of the film
layers of the display apparatus of the second embodiment of the
invention. FIG. 8 is a transmittance distribution diagram of the
display apparatus of FIG. 7 operated in anti-peep mode. Referring
to FIG. 7 and FIG. 8, the difference between a display apparatus
10A of the embodiment and the display apparatus 10 of FIG. 2 is: a
second alignment direction AD2' of a second alignment layer AL2' of
a first electronically controlled viewing angle switch 210' of the
display apparatus 10A is an axial direction perpendicular to the
first absorption axis AX1 of the first polarizer 310 (that is, a
first alignment direction AD1' of a first alignment layer AL1' of
the first electronically controlled viewing angle switch 210' is
parallel to the axial direction of the first absorption axis AX1 of
the first polarizer 310). Accordingly, the viewing angle range of
the display apparatus 10A in an oblique azimuth angle (for example,
an azimuth angle of 60 degrees or an azimuth angle of 120 degrees
on the XY plane) may be enlarged (as shown in FIG. 8).
[0064] FIG. 9 is a schematic diagram of a portion of the film
layers of the display apparatus of the third embodiment of the
invention. Referring to FIG. 9, the difference between a display
apparatus 10B of the embodiment and the display device 10A of FIG.
7 is that the axial direction of the absorption axis of the
polarizer is different. Specifically, an axial direction of a third
absorption axis AX3' of a third polarizer 330' of the display panel
of the display apparatus 10B is parallel to the third alignment
direction AD3 of the third alignment layer AL3 and the fourth
alignment direction AD4 of the fourth alignment layer AL4. The
axial direction of a first absorption axis AX1' of a first
polarizer 310' and the axial direction of a second absorption axis
AX2' of a second polarizer 320' are perpendicular to the third
alignment direction AD3 of the third alignment layer AL3 and the
fourth alignment direction AD4 of the alignment layer AL4. In other
words, the axial direction of the first absorption axis of the
first polarizer (or the second absorption axis of the second
polarizer) of the invention may be parallel or perpendicular to the
third alignment direction AD3 of the third alignment layer AL3 and
the fourth alignment direction AD4 of the fourth alignment layer
AL4.
[0065] FIG. 10A and FIG. 10B are schematic cross-sectional views of
the display apparatus of the fourth embodiment of the invention
operated in anti-peep mode and sharing mode. FIG. 11 is a schematic
diagram of a portion of the film layers of the display apparatus of
FIG. 10A. Referring to FIG. 10A, FIG. 10B, and FIG. 11, the
difference between a display apparatus 11 of the embodiment and the
display apparatus 10 of FIG. 1A and FIG. 1B is that the arrangement
of the first liquid crystal layer of the first electronically
controlled viewing angle switch is different. In the embodiment,
when an electric field is not applied to a first liquid crystal
layer LCL1A of a first electronically controlled viewing angle
switch 210A of a viewing angle switch module 50A, the arrangement
direction of a plurality of liquid crystal molecules LC1A thereof
is substantially perpendicular to the film surface of a first
alignment layer AL1-A. More specifically, the first electronically
controlled viewing angle switch 210A of the embodiment is, for
example, a vertical alignment (VA)-type liquid crystal cell.
However, the invention is not limited thereto, and in other
embodiments, the first electrically controlled viewing angle switch
may also be an electrically controlled birefringence (ECB)-type
liquid crystal cell.
[0066] It should be mentioned that, in the embodiment, a first
alignment direction AD1-A of the first alignment layer AL1-A is
anti-parallel to a second alignment direction AD2-A of a second
alignment layer AL2-A, and the included angle with the axial
direction of the first absorption axis AX1 of the first polarizer
310 is 45 degrees. The following exemplifies the anti-peep mode and
the sharing mode of the display apparatus 11.
[0067] First, non-polarized light beams from the backlight module
BLU, such as a light beam LB4 emitted in the forward direction and
two light beams LB5 and LB6 emitted obliquely, have the first
linear polarization P1 after passing through the display panel DP.
For example, the orthogonal projection of the polarization
direction of the first linear polarization P1 on the third
polarizer 330 may be parallel to the axial direction of the third
absorption axis AX3, but is not limited thereto. In other
embodiments, the light beam passing through the display panel DP
may also have elliptical polarization, and the long axis of the
elliptical polarization is substantially perpendicular to the
second absorption axis AX2 of the second polarizer 320.
[0068] Different from the display apparatus 10 of FIG. 1A, when the
display apparatus 11 of the embodiment is operated in anti-peep
mode (as shown in FIG. 10A), the first electronically controlled
viewing angle switch 210A and the second electronically controlled
viewing angle switch 220 are not enabled. That is, a voltage is not
applied between the first electrode E1 and the second electrode E2
of the first electronically controlled viewing angle switch 210A,
and a voltage is not applied between the third electrode E3 and the
fourth electrode E4 of the second electronically controlled viewing
angle switch 220.
[0069] When an electric field is not applied to the second liquid
crystal layer LCL2 of the second electronically controlled viewing
angle switch 220, the plurality of liquid crystal molecules LC2 are
arranged in a manner parallel to the axial direction of the second
absorption axis AX2 of the second polarizer 320 and the film
surface of the third alignment layer AL3 (or the fourth alignment
layer AL4). Therefore, after the light beam from the display panel
DP passes through the second polarizer 320, the second electrically
controlled viewing angle switch 220, and the first polarizer 310 in
order, the polarization state thereof and the intensity of the
polarized electric field are not changed. Similarly, when an
electric field is not applied to the first liquid crystal layer
LCL1A of the first electronically controlled viewing angle switch
210A, the plurality of liquid crystal molecules LC1A are arranged
in a manner perpendicular to the film surface of the first
alignment layer AL1-A. Therefore, after the light beam from the
second electronically controlled viewing angle switch 220 passes
through the first electronically controlled viewing angle switch
210A, the polarization state therefor and the intensity of the
polarized electric field are not changed either.
[0070] Therefore, the light beam LB4 incident on the viewing angle
limiter 100 in the forward direction is not absorbed because the
electric field polarization direction thereof is perpendicular to
the axial direction of the absorption axis AX of the dye molecules
DM. The light components of the light beam LB5 and the light beam
LB6 incident obliquely to the viewing angle limiter 100 and having
an electric field polarization direction parallel to the absorption
axis AX of the dye molecules DM are absorbed by the dye molecules
DM. Due to the different optical path lengths of the light beams
with different incident angles in the viewing angle limiter 100 and
the different included angles between the polarization directions
of the electric fields of the light beams and the absorption axis
AX, the degree of absorption of the light component of the first
linear polarization P1 is also different. For example: the greater
the incident angle of the light, the more the light component of
the first linear polarization P1 is absorbed by the dye molecules
DM. Therefore, the viewing angle limiter 100 may have a light
filter effect with a large viewing angle.
[0071] Via the light filter effect of the viewing angle limiter 100
at a large viewing angle, the user may operate the display
apparatus 11 in a smaller viewing angle range in the direction X to
achieve an anti-peep effect.
[0072] Furthermore, when the display apparatus 11 is operated in
sharing mode (as shown in FIG. 10B), both the first electronically
controlled viewing angle switch 210A and the second electronically
controlled viewing angle switch 220 are enabled. That is, a voltage
is applied between the first electrode E1 and the second electrode
E2 of the first electronically controlled viewing angle switch
210A, and a voltage is applied between the third electrode E3 and
the fourth electrode E4 of the second electronically controlled
viewing angle switch 220.
[0073] When an electric field is applied to the second liquid
crystal layer LCL2 of the second electronically controlled viewing
angle switch 220, a portion of the liquid crystal molecules LC2 is
arranged obliquely on the YZ plane (for example, the included angle
between the optical axis of the liquid crystal molecules LC1 and
the film surface of the third alignment layer AL3 is greater than
45 degrees and less than or equal to 90 degrees). Therefore, after
a light beam LB5' and a light beam LB6' incident obliquely pass
through the second polarizer 320, the second electrically
controlled viewing angle switch 220, and the first polarizer 310 in
order, the polarization state thereof is changed into the first
linear polarization P1' in which the intensity of the polarized
electric field is weakened. After a light beam LB4' incident
normally passes through the second polarizer 320, the second
electronically controlled viewing angle switch 220, and the first
polarizer 310, the polarization state thereof and the intensity of
the polarized electric field remain unchanged. That is, the light
beam LB4' still has the first linear polarization P1.
[0074] When an electric field is applied to the first liquid
crystal layer LCL1A of the first electronically controlled viewing
angle switch 210A, most of the liquid crystal molecules LC1A are
arranged obliquely to the film surfaces of the first alignment
layer AL1 and the second alignment layer AL2, and the included
angle between the orthogonal projection of the liquid crystal
molecules LC1 on the XY plane and the direction X or the direction
Y is about 45 degrees, for example. Therefore, the polarization
states of the light beam LB4' incident on the first liquid crystal
layer LCL1A in the forward direction and the light beam LB5' and
the light beam LB6' incident on the first liquid crystal layer
LCL1A obliquely are all changed due to the change of the amount of
phase retardation of the first liquid crystal layer LCL1A, such as
changed from the first linear polarization P1 to the second linear
polarization P2 and changed from the first linear polarization P1'
to a second linear polarization P2'.
[0075] The electric field polarization direction of the light beam
from the first electronically controlled viewing angle switch 210A
is perpendicular to the axial direction of the absorption axis AX
of the dye molecules DM. Therefore, both the light beam LB5' and
the light beam LB6' incident obliquely or the light beam LB4'
incident normally may pass through the viewing angle limiter 100
without substantial optical energy loss. In other words, the user
may operate the display apparatus 10 in the direction X with a
larger viewing angle range to achieve the effect of display image
sharing.
[0076] FIG. 12 is a schematic cross-sectional view of the display
apparatus of the fifth embodiment of the invention. FIG. 13 is a
schematic diagram of a portion of the film layers of the display
apparatus of FIG. 12. FIG. 14 is a schematic diagram of a portion
of the film layers of the display apparatus of the sixth embodiment
of the invention. Referring to FIG. 12 and FIG. 13, the difference
between a display apparatus 12 of the embodiment and the display
apparatus 10 of FIG. 1A is the different arrangement of the display
panel and the different axial direction arrangement of the
absorption axis of the polarizer. Specifically, a display panel
DP-A of the display apparatus 12 is located between the first
electronically controlled viewing angle switch 210 and the second
electronically controlled viewing angle switch 220 of a viewing
angle switch module 50', and the display panel DP-A is located
between the viewing angle limiter 100 and the backlight module BLU.
In the display apparatus 12, for example, the backlight module BLU,
the second electronically controlled viewing angle switch 220, the
display panel DP-A, the first electronically controlled viewing
angle switch 210, and the viewing angle limiter 100 are arranged in
order to be overlapped. It should be noted that the third polarizer
330' of the display panel DP-A is disposed at one side of the
liquid crystal cell LCC away from the second electronically
controlled viewing angle switch 220.
[0077] Moreover, in the embodiment, the axial direction of the
third absorption axis AX3' of the third polarizer 330' may be
parallel to the third alignment direction AD3 of the third
alignment layer AL3 and the fourth alignment direction AD4 of the
fourth alignment layer AL4, and the axial direction of the first
absorption axis AX1' of the first polarizer 310' and the axial
direction of the second absorption axis AX2' of the second
polarizer 320' are perpendicular to the axial direction of the
third absorption axis AX3' of the third polarizer 330'. However,
the invention is not limited thereto, and in other embodiments, the
arrangement relationship between the axial direction of the
absorption axis of each of the plurality of polarizers of a display
apparatus 12A and the alignment direction of each of the alignment
layers of the two electronically controlled viewing angle switches
(as shown in FIG. 14) may also be similar to the display apparatus
10 of FIG. 2.
[0078] Since the operation mode of the display apparatus 12 of the
embodiment is similar to the operation mode of the display
apparatus 10 of FIG. 1A and FIG. 1B, for detailed description,
please refer to the relevant paragraphs of the above embodiments,
which is not repeated herein.
[0079] FIG. 15 is a schematic cross-sectional view of the display
apparatus of the seventh embodiment of the invention. FIG. 16 is a
schematic diagram of a portion of the film layers of the display
apparatus of FIG. 15. Referring to FIG. 15 and FIG. 16, the main
difference between a display apparatus 13 of the embodiment and the
display apparatus 10 of FIG. 1A is the configuration of the display
panel is different. In the embodiment, a viewing angle switch
module 50B of the display apparatus 13 may be optionally disposed
between the display panel DP-A and the backlight module BLU,
wherein a first electronically controlled viewing angle switch 210R
and the viewing angle limiter 100 are located between the display
panel DP-A and the backlight module BLU, and a second
electronically controlled viewing angle switch 220R is located
between the display panel DP-A and the first electronically
controlled viewing angle switch 210R. In the display apparatus 13,
for example, the backlight module BLU, the viewing angle limiter
100, the first electronically controlled viewing angle switch 210R,
the second electronically controlled viewing angle switch 220R, and
the display panel DP-A are arranged in order to be overlapped. It
should be noted that, the arrangement order of the film layers of
the first electronically controlled viewing angle switch 210R and
the second electronically controlled viewing angle switch 220R in
the light beam traveling direction of the embodiment is opposite to
the arrangement order of the film layers of the first
electronically controlled viewing angle switch 210 and the second
electronically controlled viewing angle switch 220 of the display
apparatus 10 of FIG. 1A in the light beam traveling direction.
[0080] In the embodiment, since the viewing angle limiter 100 is
disposed closer to the position of the backlight module BLU, a
portion of the light beam from the backlight module BLU may have a
linear polarization state after passing through the viewing angle
limiter 100, and another portion of the light beam may still remain
unpolarized after passing through the viewing angle limiter
100.
[0081] For example, the light beam normally incident on the viewing
angle limiter 100 is not absorbed because the optical path thereof
is parallel to the axial direction of the absorption axis AX of the
dye molecules DM, so that the forward light beam passing through
the viewing angle limiter 100 still has an unpolarized state. At
least a portion of the light energy of the light beam incident
obliquely to the viewing angle limiter 100 is absorbed by the dye
molecules DM because the light path thereof is intersected with the
axial direction of the absorption axis AX of the dye molecules DM,
so that the oblique light beam passing through the viewing angle
limiter 100 has different degrees of polarization. More
specifically, the degree of polarization of the light beam passing
through the viewing angle limiter 100 is increased as the incident
angle of the light beam is increased.
[0082] Since the working principle of each of the first
electronically controlled viewing angle switch 210R and the second
electronically controlled viewing angle switch 220R of the viewing
angle switch module 50B of the embodiment for oblique light beams
in different modes is similar to that of the viewing angle switch
module 50 of FIG. 1A, for detailed description, please refer to the
relevant paragraphs of the above embodiments, which is not repeated
herein.
[0083] FIG. 17 is a schematic cross-sectional view of the display
apparatus of the eighth embodiment of the invention. FIG. 18 is a
schematic diagram of a portion of the film layers of the display
apparatus of FIG. 17. Referring to FIG. 17 and FIG. 18, the
difference between a display apparatus 14 of the embodiment and the
display apparatus 13 of FIG. 15 is that the display panel DP of the
display apparatus 14 is disposed between the first electronically
controlled viewing angle switch 210R and the second electronically
controlled viewing angle switch 220R. In the display apparatus 14,
for example, the backlight module BLU, the viewing angle limiter
100, the first electronically controlled viewing angle switch 210R,
the display panel DP, and the second electronically controlled
viewing angle switch 220R are arranged in order to be overlapped.
Since the operating principle of the display apparatus 14 of the
embodiment in different modes is similar to that of the display
apparatus 13 of FIG. 15, for detailed description, please refer to
the relevant paragraphs of the above embodiments, which is not
repeated herein.
[0084] FIG. 19 is a schematic cross-sectional view of the display
apparatus of the ninth embodiment of the invention. FIG. 20 is a
schematic diagram of a portion of the film layers of the display
apparatus of FIG. 19. Referring to FIG. 19 and FIG. 20, the
difference between a display apparatus 15 of the embodiment and the
display apparatus 10 of FIG. 1A is the display apparatus 15 further
includes a compensation film 400 disposed between the viewing angle
limiter 100 and the first electronically controlled viewing angle
switch 210. For example, in the embodiment, the axial direction of
an optical axis n of the compensation film 400 may be parallel to
the axial direction of the first absorption axis AX1 of the first
polarizer 310, but is not limited thereto. In other embodiments,
the axial direction of the optical axis of the compensation film
may also be perpendicular to the axial direction of the first
absorption axis AX1 of the first polarizer 310. Via the arrangement
of the compensation film 400, the anti-peep range or the viewing
angle range of the display apparatus 15 in a specific direction
(for example, the direction X) may be expanded or reduced.
[0085] Based on the above, in the viewing angle switch module and
the display apparatus of an embodiment of the invention, via the
absorption characteristics of the viewing angle limiter in a
specific direction and the cooperation with the two electronically
controlled viewing angle switches, the light energy utilization
rate of the viewing angle switch module may be increased, thereby
reducing the operating energy consumption of the display apparatus.
At the same time, the anti-peep effect of the display apparatus
under a large viewing angle may also be improved. Moreover, the
electronically controllable features of the two electronically
controlled viewing angle switches make it extremely convenient for
the display apparatus to switch between anti-peep mode and sharing
mode.
[0086] The foregoing description of the preferred embodiments of
the invention has been presented for purposes of illustration and
description. It is not intended to be exhaustive or to limit the
invention to the precise form or to exemplary embodiments
disclosed. Accordingly, the foregoing description should be
regarded as illustrative rather than restrictive. Obviously, many
modifications and variations will be apparent to practitioners
skilled in this art. The embodiments are chosen and described in
order to best explain the principles of the invention and its best
mode practical application, thereby to enable persons skilled in
the art to understand the invention for various embodiments and
with various modifications as are suited to the particular use or
implementation contemplated. It is intended that the scope of the
invention be defined by the claims appended hereto and their
equivalents in which all terms are meant in their broadest
reasonable sense unless otherwise indicated. Therefore, the term
"the invention", "the present invention" or the like does not
necessarily limit the claim scope to a specific embodiment, and the
reference to particularly preferred exemplary embodiments of the
invention does not imply a limitation on the invention, and no such
limitation is to be inferred. The invention is limited only by the
spirit and scope of the appended claims. Moreover, these claims may
refer to use "first", "second", etc. following with noun or
element. Such terms should be understood as a nomenclature and
should not be construed as giving the limitation on the number of
the elements modified by such nomenclature unless specific number
has been given. The abstract of the disclosure is provided to
comply with the rules requiring an abstract, which will allow a
searcher to quickly ascertain the subject matter of the technical
disclosure of any patent issued from this disclosure. It is
submitted with the understanding that it will not be used to
interpret or limit the scope or meaning of the claims. Any
advantages and benefits described may not apply to all embodiments
of the invention. It should be appreciated that variations may be
made in the embodiments described by persons skilled in the art
without departing from the scope of the invention as defined by the
following claims. Moreover, no element and component in the
disclosure is intended to be dedicated to the public regardless of
whether the element or component is explicitly recited in the
following claims.
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