U.S. patent application number 16/736821 was filed with the patent office on 2021-07-08 for head up display system and display method of head up display system.
This patent application is currently assigned to Himax Display, Inc.. The applicant listed for this patent is Himax Display, Inc.. Invention is credited to Kuan-Hsu Fan-Chiang.
Application Number | 20210208391 16/736821 |
Document ID | / |
Family ID | 1000004606190 |
Filed Date | 2021-07-08 |
United States Patent
Application |
20210208391 |
Kind Code |
A1 |
Fan-Chiang; Kuan-Hsu |
July 8, 2021 |
HEAD UP DISPLAY SYSTEM AND DISPLAY METHOD OF HEAD UP DISPLAY
SYSTEM
Abstract
A head up display system is provided and includes an image
source, an image adjustment device, a controller, and a reflector.
The image source is adapted to output an image with an image light
traveling in a light path. The image adjustment device is
positioned on the light path of the image light, wherein the image
adjustment device comprises a liquid crystal panel. The controller
is adapted to control the image adjustment device. The reflector is
adapted to reflect the image light passing through the image
adjustment device to a projection screen. A display method of a
head up display system is also provided in the disclosure.
Inventors: |
Fan-Chiang; Kuan-Hsu;
(Tainan City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Himax Display, Inc. |
Tainan City |
|
TW |
|
|
Assignee: |
Himax Display, Inc.
Tainan City
TW
|
Family ID: |
1000004606190 |
Appl. No.: |
16/736821 |
Filed: |
January 8, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 27/0179 20130101;
G02B 2027/0185 20130101; G02F 1/134309 20130101; G02B 27/0101
20130101; B60K 2370/1529 20190501; B60K 35/00 20130101 |
International
Class: |
G02B 27/01 20060101
G02B027/01; G02F 1/1343 20060101 G02F001/1343; B60K 35/00 20060101
B60K035/00 |
Claims
1. A head up display system, comprising: an image source adapted to
output an intermediate image with an image light traveling in a
light path; an image adjustment device positioned on the light path
of the image light, wherein the image adjustment device comprises a
first liquid crystal panel; a controller adapted to control the
image adjustment device; and a reflector adapted to reflect the
image light passing through the image adjustment device to a
projection screen, wherein the image adjustment device further
comprises a second liquid crystal panel positioned on the light
path, and the controller controls the first liquid crystal panel
and the second liquid crystal panel to operate independently.
2. The head up display system of claim 1, wherein the first liquid
crystal panel comprises a first electrode, a second electrode and a
liquid crystal layer disposed between the first electrode and the
second electrode.
3. The head up display system of claim 2, wherein each of the first
electrode and the second electrode completely and continuously
covers an active area of the first liquid crystal panel.
4. (canceled)
5. The head up display system of claim 1, wherein the first liquid
crystal panel is a phase retarder, the second liquid crystal panel
is a liquid crystal lens, and the second liquid crystal panel is
positioned between the first liquid crystal panel and the image
source.
6. The head up display system of claim 1, wherein the second liquid
crystal panel comprises a first electrode, a second electrode and a
liquid crystal layer disposed between the first electrode and the
second electrode, and the first electrode, the second electrode or
both is patterned into pixels.
7. (canceled)
8. The head up display system of claim 1, wherein one or both of
the first liquid crystal panel and the second liquid crystal panel
comprises electrodes patterned into irregular patterns.
9. The head up display system of claim 8, wherein one of the first
liquid crystal panel and the second liquid crystal panel is
positioned at a first focal plane of the image source and the other
of the first liquid crystal panel and the second liquid crystal
panel is positioned at a second focal plane of the image
source.
10. The head up display system of claim 1, wherein the image source
comprises a display panel and a light source providing an initial
light to the display panel.
11. The head up display system of claim 10, wherein the display
panel comprises a liquid crystal on silicon panel-spatial light
modulator.
12. The head up display system of claim 10, wherein the light
source comprises a laser light source, an LED light source, or a
combination thereof.
13. The head up display system of claim 1, wherein the reflector
comprises a concave mirror.
14. A display method of a head up display system, comprising:
generating an intermediate image by an image source; adjusting an
image light of the intermediate image by an image adjustment
device, wherein the image adjustment device comprises a liquid
crystal panel; reflecting the image light passing through the image
adjustment device to a projection screen.
15. The method of claim 14, wherein an imaging position of the
image is adjusted by the image adjustment device.
16. The method of claim 14, wherein a size of the intermediate
image is adjusted by the image adjustment device.
17. The method of claim 14, wherein the image adjustment device
comprises a first liquid crystal panel and a second liquid crystal
panel, the first liquid crystal panel is positioned at a first
focal plane of the image source, the second liquid crystal panel is
positioned at a second focal plane of the image source, and the
first liquid crystal panel and the second liquid crystal panel
operate in a diffusing mode in different time sequences.
Description
BACKGROUND
Technical Field
[0001] The disclosure is related to a display technique, and
particularly, to a head up display system and a display method
thereof.
Description of Related Art
[0002] In recent years, a head-up display (HUD) that projects light
onto the windshield of the vehicle such as an automobile, a train,
a ship, a construction machine, an aircraft, or an agricultural
machine, or a combiner disposed in the vicinity of the windshield
as a screen, to display an image is known. The HUD reflects images
on the windshield or the like to display information into drivers'
field of view. The images projected onto the windshield may require
different imaging distances so that some of the information in the
projected image would be presented in a far image that is able to
be integrated into the real environment while some of the
information in the projected image would be presented in a near
image, which enables the driver to confirm route guidance,
emergency information, vehicle status, and the like without largely
changing the line of sight.
SUMMARY
[0003] The disclosure is related to a head up display system
capable of dynamically adjusting the imaging condition of the
image.
[0004] The disclosure is related to a display method of a head up
display system to dynamically adjust the imaging condition of the
image.
[0005] In some embodiments of the disclosure, a head up display
system includes an image source, an image adjustment device, a
controller, and a reflector. The image source is adapted to output
an image with an image light traveling in a light path. The image
adjustment device is positioned on the light path of the image
light, wherein the image adjustment device comprises a liquid
crystal panel. The controller is adapted to control the image
adjustment device. The reflector is adapted to reflect the image
light passing through the image adjustment device to a projection
screen.
[0006] In some embodiments of the disclosure, the liquid crystal
panel includes a first electrode, a second electrode and a liquid
crystal layer disposed between the first electrode and the second
electrode.
[0007] In some embodiments of the disclosure, each of the first
electrode and the second electrode completely and continuously
covers an active area of the liquid crystal panel.
[0008] In some embodiments of the disclosure, the image adjustment
device further includes a second liquid crystal panel positioned on
the light path.
[0009] In some embodiments of the disclosure, the liquid crystal
panel is a phase retarder, the second liquid crystal panel is a
liquid crystal lens, and the second liquid crystal panel is
positioned between the liquid crystal and the image source.
[0010] In some embodiments of the disclosure, the second liquid
crystal panel includes a first electrode, a second electrode and a
liquid crystal layer disposed between the first electrode and the
second electrode, and the first electrode, the second electrode or
both is patterned into pixels.
[0011] In some embodiments of the disclosure, the controller
controls the liquid crystal panel and the second liquid crystal
panel to operate independently.
[0012] In some embodiments of the disclosure, one or both of the
liquid crystal panel and the second liquid crystal panel includes
electrodes patterned into irregular patterns.
[0013] In some embodiments of the disclosure, one of the liquid
crystal panel and the second liquid crystal panel is positioned at
a first focal plane of the image source and the other of the liquid
crystal panel and the second liquid crystal panel is positioned at
a second focal plane of the image source.
[0014] In some embodiments of the disclosure, the image source
includes a display panel and a light source providing an initial
light to the display panel.
[0015] In some embodiments of the disclosure, the display panel
includes a liquid crystal on silicon panel-spatial light
modulator.
[0016] In some embodiments of the disclosure, the light source
includes a laser light source, an LED light source, or a
combination thereof.
[0017] In some embodiments of the disclosure, the reflector
includes a concave mirror.
[0018] In some embodiments of the disclosure, a display method of a
head up display system includes the following steps, but not
limited thereto. An image us provided by an image source. An image
light of the image is adjusted by an image adjustment device that
includes a liquid crystal panel. The image light passing through
the image adjustment device is reflected to a projection
screen.
[0019] In some embodiments of the disclosure, an imaging position
of the image is adjusted by the image adjustment device.
[0020] In some embodiments of the disclosure, a size of the image
is adjusted by the image adjustment device.
[0021] In some embodiments of the disclosure, the image adjustment
device includes a first liquid crystal panel and a second liquid
crystal panel, the first liquid crystal panel is positioned at a
first focal plane of the image source, the second liquid crystal
panel is positioned at a second focal plane of the image source,
and the first liquid crystal panel and the second liquid crystal
panel operate in a diffusing mode in different time sequences.
[0022] In view of the above, the head up display system in
accordance with the embodiments of the disclosure includes an image
adjustment device that is comprised of at least one liquid crystal
display panel capable of dynamically adjust the imaging condition
of the image. Accordingly, the imaging distance of the image
generated by the head up display system may be adjusted to achieve
multiple distances of image. In addition, the image adjustment
device may be an electrical controllable device to achieve the
multi-levels adjustments for the imaging conditions so that the
head up display system may generate various images based on
different situations.
[0023] To make the aforementioned more comprehensible, several
embodiments accompanied with drawings are described in detail as
follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The accompanying drawings are included to provide a further
understanding of the disclosure, and are incorporated in and
constitute a part of this specification. The drawings illustrate
exemplary embodiments of the disclosure and, together with the
description, serve to explain the principles of the disclosure.
[0025] FIG. 1 schematically illustrates an application of a head up
display system in accordance with some embodiments of the
disclosure.
[0026] FIG. 2 schematically illustrates a head up display system in
accordance with some embodiments of the disclosure.
[0027] FIG. 3 schematically illustrates a head up display system in
accordance with some embodiments of the disclosure.
[0028] FIG. 4 schematically illustrates a head up display system in
accordance with some embodiments of the disclosure.
DESCRIPTION OF THE EMBODIMENTS
[0029] FIG. 1 schematically illustrates an application of a head up
display system in accordance with some embodiments of the
disclosure. In FIG. 1, the head up display system 100 is, for
example, equipped on an automobile 2, and FIG. 1 only illustrates a
portion of the automobile 2. The head up display system 100 may
generate an image projecting onto a windshield 4 of the automobile
2. Specifically, the image light 6 of the image projected onto the
windshield 4 may create a virtual image 8 that the user 10, the
driver, may observe. In the present embodiment, the imaging
distance D8 of the virtual image 8 observed by the user 10 may be
adjustable by the head up display system 100. If the virtual image
8 contains the information that is suitable to be merged into the
environment that is seen by the user 10, the imaging distance D8 of
the virtual image 8 may be adjusted to be relatively large as a far
image. If the virtual image 8 contains the information that relates
to the vehicle status such as the speedometer, the tachometer, the
odometer, the engine coolant temperature gauge, the fuel gauge, the
turn indicators, the gearshift position indicator, the seat belt
warning light, the parking-brake warning light, the
engine-malfunction lights, the like, or any combination thereof,
the imaging distance D8 of the virtual image 8 may be adjusted to
be relatively small as a near image. Accordingly, the head up
display system 100 may provide an intuitional visual effect for the
user 10 without largely changing the line of sight of the user
10.
[0030] FIG. 2 schematically illustrates a head up display system in
accordance with some embodiments of the disclosure. In FIG. 2, the
head up display system 100A may serve as an exemplary example for
the head up display system 100 shown in FIG. 1; however, the
disclosure is not limited thereto. The head up display system 100A
may include an image source 110, an image adjustment device 120A, a
controller 130A, and a reflector 140. The image source 110 may
generate an image with the image light traveling in a light path
P1. The image adjustment device 120A may be positioned on the light
path P1. The controller 130A may be electrically communicated with
the image adjustment device 120A and adapted to control the
operation of the image adjustment device 120A. The reflector 140
may be positioned at the downstream of the image adjustment device
120A on the light path P1. The image light generated by the image
source 110 may be subjected to the adjustment of the image
adjustment device 120A and continuously travel along the light path
P1 until being reflected by the reflector 140. The reflector 140
may reflect the image light passing through the image adjustment
device 120A to travel in another light path P2 and irradiate a
projection screen 150 such as the windscreen 4 of the automobile 2
shown in FIG. 1 to generate the virtual image VI that is observed
by the user's eye UE.
[0031] The image source 110 may include a display panel 112 and a
light source 114. The light source 114 may include a light emitting
device 114A and an optical member 114B that is positioned between
the light emitting device 114A and the display panel 112. The light
emitting device 114A may include a laser, an LED, the like, or a
combination thereof to generate an initial light for the display
panel 112. The optical member 114B may include lens, beam splitter,
polarizer, the like, or any combination thereof, to collimate or
modify the initial light generated by the light emitting device
114A so that the initial light may irradiate onto the display panel
112 with a required manner, such as a required strength, a required
color temperature, and/or the like. The display panel 112 may
generate an intermediate image by using the initial light provided
by the light source 114. Specifically, the display panel 112 may
transfer the initial light to an image light travelling in the
light path P1 and generate the intermediate image at a prescribed
position. The display panel 112 may be a reflective type display
panel and may include a liquid crystal on silicon-spatial light
modulator (LCoS-SLM). In some alternative instances, the display
panel 112 may be other type of display panel such as a transmissive
type display panel or the like. In some embodiments, the image
source 110 may include a self-illumination display panel such as an
organic light emitting display panel or the like, such that the
image source 110 may not include the light source 114.
[0032] The image adjustment device 120A may be an optical device
adapted to adjust the condition of the image light provided by the
image source 110. In some embodiments, the image adjustment device
120A may include a liquid crystal panel LCP1. For example, the
liquid crystal panel LCP1 may include a first substrate SUA1, a
second substrate SUB1 opposite to the first substrate SUA1, a first
electrode EA1 disposed on the first substrate SUA1, a second
electrode EB1 disposed on the second substrate SUB1, and a liquid
crystal layer LC1 between the first electrode EA1 and the second
electrode EB1. The first electrode EA1 and the second electrode EB1
may each completely and continuously cover an active area of the
liquid crystal panel LCP1, wherein the active area of the liquid
crustal panel LCP1 allows the image light generated by the image
source 110 to transmit therethrough. The liquid crystal panel LCP1
having continuous and non-patterned electrodes at the active area
may serve as a phase retarder which may alter the polarization
state of the wave of a light travelling through it. Namely, the
image light from the image source 110 may pass the liquid crystal
panel LCP1 and be subjected to the alteration of the polarization
state.
[0033] The controller 130A may be electrically communicated with
the image adjustment device 112A. The controller 130A may input
respective voltages to the first electrode EA1 and the second
electrode EB1 of the liquid crystal panel LCP1 so that the liquid
crystal panel LCP1 may provide desired optical effect such as phase
retardation to the wave of the image light provided by the image
source 110. In addition, the optical effect provided by the liquid
crystal panel LCP1 may be stepless controlled since the liquid
crystal panel LCP1 is electronically controllable. In some
embodiments, the controller 130A may be also electrically
communicated to the image source 110 or the controller (not shown)
of the image source 110 and may control the operation of the image
adjustment device 120A based on the information of the intermediate
image to be generated by the image source 110.
[0034] The reflector 140 may be adapted to reflect the image light
toward the projection screen 150 after the image light passes
through the image adjustment device 120A. The image light provided
by the image source 110 initially traveling in the light path P1
may be reflected to travel in the light path P2 by the reflector
140. The image light travelling in the light path P2 may project on
the projection screen 150 to create the virtual image VI observed
by the user's eye UE. In some embodiments, the reflector 140 may be
a concaved mirror. The curvature of the concaved mirror may
determine the imaging distance ID of the virtual image VI. The
greater the curvature of the concaved mirror is the further the
imaging distance ID is. In some embodiments, the concaved mirror
may have a non-fixed curvature so that the reflecting effect of the
reflector 140 may be suitable for various curvatures of the
projection screen 150.
[0035] In the head up display system 100A, the image source 110 may
provide the image light travelling in the light path P1 to generate
an intermediate image at a prescribed focal plane and the image
light may be reflected by the reflector 140 to irradiate onto the
projection screen 150 to generate the virtual image VI that is
observed by the user's eye UE. In some instances, the image
adjustment device 120A may be controlled to present a transparent
state without providing an optical adjustment function so that the
intermediate image may be positioned at the prescribed focal plane
and the virtual image VI may have a first status of the imaging
distance ID. In some alternative instances, the image adjustment
device 120A may be controlled to serve as a phase retarder, and the
image adjustment device 120A may alter the phase retardation of the
image light provided by the image source 110. As such, the imaging
position of the intermediate image may be adjusted and the imaging
distance ID of the virtual image VI may be changed accordingly. For
example, the virtual image VI may have a second status of the
imaging distance ID and the imaging distance ID in the second
status is different than the imaging distance ID in the first
status. Accordingly, the image adjustment device 120A may adjust
the imaging light to achieve various imaging distances ID of the
virtual image VI to enhance the flexibility of the real use.
[0036] In the present embodiment, the imaging distance ID may be
adjusted based on the information to be presented in the virtual
image VI. For example, the information of route guidance may be
presented in the virtual image VI with a relative larger imaging
distance ID and the information of the speedometer, the tachometer,
the odometer, the engine coolant temperature gauge, the fuel gauge
or the like may be presented in the virtual image VI with a
relative smaller imaging distance ID. In some instances, the
virtual image VI with the larger imaging distance ID may be merged
into the environment that is seen by the user's eye UE and the
virtual image VI with the shorter imaging distance ID may be
observed as an image presented on the projection screen 150, but
the disclosure is not limited thereto. In addition, the image
adjustment device 120A may adjust the imaging result of the virtual
image VI in a stepless manner so that the head up display system
100B may provide a desirable display effect on various projection
screens such as the windshields with various curvatures and oblique
degrees. In other words, the application of the head up display
system 100B may be more flexible without being restricted to be
collocated with a prescribed type of the projection screen 150.
[0037] FIG. 3 schematically illustrates a head up display system in
accordance with some embodiments of the disclosure. In FIG. 3, the
head up display system 100B may serve as an exemplary example for
the head up display system 100 shown in FIG. 1; however, the
disclosure is not limited thereto. Similar to the head up display
system 100A, the head up display system 100B includes an image
source 110, an image adjustment device 120B, a controller 130B, and
a reflector 140 and is adapted to project the image light onto a
projection screen 150 for creating the virtual image VI capable of
observed by the user's eye UE. In the two embodiments depicted in
FIG. 2 and FIG. 3, the same or similar elements are indicated by
the same or similar reference numbers; for example, the image
source 110, the reflector 140 and the projection screen 150 may be
the same of those described in the above embodiment in FIG. 2 so
that the details for the image source 110, the reflector 140 and
the projection screen 150 may refer to the detail descriptions of
the above embodiment.
[0038] In the present embodiment, the image adjustment device 120B
may include a liquid crystal panel LCP1 positioned between the
image source 110 and the reflector 140, and a liquid crystal panel
LCP2 positioned between the liquid crystal panel LCP1 and the image
source 110. The controller 130B is electrically communicated with
both the liquid crystal panel LCP1 and the liquid crystal panel
LCP2 and is adapted to control the operation of the liquid crystal
panel LCP1 and the liquid crystal panel LCP2. Both the liquid
crystal panel LCP1 and the liquid crystal panel LCP2 are positioned
on the light path P1 of the image light provided by the image
source 110 and between the image source 110 and the reflector
140.
[0039] The liquid crystal panel LCP1 may be electronically
controllable and provide the optical function as a phase retarder
to adjust the polarization of the wave of the image light provided
by the image source 110. The liquid crystal panel LCP1 may have a
similar structure and function as the liquid crystal panel LCP1
depicted in FIG. 2. The liquid crystal panel LCP2 may also be
electronically controllable and may serve as a liquid crystal lens.
Specifically, the liquid crystal panel LCP2 may include a first
substrate SUA2, a second substrate SUB2 opposite to the first
substrate SUA2, a first electrode EA2 disposed on the first
substrate SUA2, a second electrode EB2 disposed on the second
substrate SUB2, and a liquid crystal layer LC2 between the first
electrode EA2 and the second electrode EB2. The first electrode EA2
and the second electrode EB2 are patterned into pixels in the
present embodiment to achieve the function of a liquid crystal
lens.
[0040] The image light provided by the image source 110 may travel
in the light path P1, sequentially pass through the liquid crystal
panel LCP2 and the liquid crystal panel LCP1, and be reflected by
the reflector 140 to irradiate onto the projection screen 150 and
create the virtual image VI capable of being observed by the user's
eye UE. The liquid crystal panel LCP2 may be controlled by the
controller 130B and may adjust the focus of the image light
provided by the image source 110 so that the size and/or the
imaging position of the intermediate image generated by the image
source 110 may be adjusted and the size and/or the imaging distance
ID of the virtual image VI may be changed accordingly. The liquid
crystal panel LCP1 may be controlled by the controller 130B to
alter the polarization of the image light passing through the
liquid crystal panel LCP1 so that the imaging distance ID of the
virtual image VI may be further adjusted by the liquid crystal
panel LCP1.
[0041] By the operation and control of both the liquid crystal
panel LCP1 and the liquid crystal panel LCP2, the size, the imaging
distance or both of the virtual image VI may be adjusted based on
the information presented in the virtual image VI. In some
embodiments, the liquid crystal panel LCP1 and the liquid crystal
panel LCP2 may operate independently and provide respective optical
adjustment functions in a stepless manner. For example, the
controller 130B may control the liquid crystal panel LCP2 to
operate a convex/concave lens function while control the liquid
crystal panel LCP1 to present a transparent status without having a
phase retardation function. Alternatively, the controller 130B may
control the liquid crystal panel LCP1 to present a phase
retardation function while control the liquid crystal panel LCP2 to
present a transparent status without having a convex/concave lens
function. In another embodiment, the controller 130B may control
the liquid crystal panel LCP1 to present a phase retardation
function and also control the liquid crystal panel LCP2 to operate
a convex/concave lens function. Therefore, the virtual image VI may
be created with various imaging conditions. In some embodiments
that is not shown in the drawing, the image adjustment device may
include the liquid crystal panel LCP2 without the liquid crystal
panel LCP1 and may also achieve the effect of generating the
virtual image VI at various imaging conditions.
[0042] FIG. 4 schematically illustrates a head up display system in
accordance with some embodiments of the disclosure. In FIG. 4, the
head up display system 100C may serve as an exemplary example for
the head up display system 100 shown in FIG. 1; however, the
disclosure is not limited thereto. Similar to the head up display
system 100A in FIG. 2, the head up display system 100C includes an
image source 110, an image adjustment device 120C, a controller
130C, and a reflector 140 and is adapted to project the image light
onto a projection screen 150 to create the virtual image VI
observed by the user's eye UE. In the two embodiments of FIG. 2 and
FIG. 4, the same or similar elements are indicated by the same or
similar reference numbers; for example, the image source 110, the
reflector 140 and the projection screen 150 may be the same of
those described in the above embodiments depicted in FIG. 2 so that
the details for the image source 110, the reflector 140 and the
projection screen 150 may refer to the detail descriptions of the
above embodiment.
[0043] In the present embodiment, the image adjustment device 120C
may include a liquid crystal panel LCP3 between the image source
110 and the reflector 140, and a liquid crystal panel LCP4
positioned between the liquid crystal panel LCP3 and the reflector
140. The controller 130C is electrically communicated with both the
liquid crystal panel LCP3 and the liquid crystal panel LCP4 and is
adapted to control the operations of the liquid crystal panel LCP3
and the liquid crystal panel LCP4. Both the liquid crystal panel
LCP3 and the liquid crystal panel LCP4 are positioned on the light
path P1 of the image light provided by the image source 110.
[0044] In the present embodiment, the liquid crystal panel LCP3 may
be electronically controllable and may include a first substrate
SUA3, a second substrate SUB3 opposite to the first substrate SUA3,
a first electrode EA3 disposed on the first substrate SUA3, a
second electrode EB3 disposed on the second substrate SUB3, and a
liquid crystal layer LC3 between the first electrode EA3 and the
second electrode EB3. The first electrode EA3 and the second
electrode EB3 are patterned into irregular patterns in the present
embodiment though FIG. 4 does not show the irregular patterns for
illustration purpose. The liquid crystal panel LCP3 may serve as an
electronically controllable diffuser and be controlled by the
controller 130C to operate required optical function.
[0045] The liquid crystal panel LCP4 may have a structure similar
to that of the liquid crystal panel LCP4. Specifically, the liquid
crystal panel LCP4 may include a first substrate SUA4, a second
substrate SUB4 opposite to the first substrate SUA4, a first
electrode EA4 disposed on the first substrate SUA4, a second
electrode EB4 disposed on the second substrate SUB4, and a liquid
crystal layer LC4 between the first electrode EA4 and the second
electrode EB4. The first electrode EA4 and the second electrode EB4
are patterned into irregular patterns in the present embodiment
though FIG. 4 does not present the irregular patterns for
illustration purpose. The liquid crystal panel LCP4 may serve as an
electronically controllable diffuser and be controlled by the
controller 130C to operate required optical function.
[0046] The image source 110 may generate the intermediate image at
multiple focal planes and the imaging distance ID of the virtual
image VI may be determined based on the position of the
intermediate image. In the present embodiment, the liquid crystal
panel LCP3 is positioned at a first focal plane of the image source
110 and the liquid crystal panel LCP4 is positioned at a second
focal plane of the image source 110. When the image source 110
generates the intermediate image at the first focal plane, the
virtual image VI may be created at a first status of the imaging
distance ID. In addition, the controller 130C may control the
liquid crystal panel LCP3 to operate the diffuser function and
control the liquid crystal panel LCP4 to present a transparent
status without having the diffusing effect. As such, the virtual
image VI created at the first status of the imaging distance ID may
be enlarged, when compared to the condition that the liquid crystal
panel LCP3 and the liquid crystal panel LCP4 both present in the
transparent status. Similarly, when the image source 110 generates
the intermediate image at the second focal plane, the virtual image
VI may be created at a second status of the imaging distance ID. In
addition, the controller 130C may control the liquid crystal panel
LCP4 to operate the diffuser function and control the liquid
crystal panel LCP3 to present a transparent status without having
the diffusing effect. As such, the virtual image VI created at the
second status of the imaging distance ID may be enlarged, when
compared to the condition that the liquid crystal panel LCP3 and
the liquid crystal panel LCP4 both present in the transparent
status. In some embodiments, the liquid crystal panel LCP3 and the
liquid crystal panel LCP4 may operate the diffuser function based
on the intermediate image generated by the image source without
simultaneously present the diffuser function. In other words, the
liquid crystal panel LCP3 and the liquid crystal panel LCP4 operate
in a diffusing mode in different time sequences. In some
embodiments, the image source 110 may generate the intermediate
image at more focal planes, and the image adjustment device 120C
may include more liquid crystal panels positioned at respective
focal planes of the image source 110. Based on the above
embodiments, one or more of the liquid crystal panel LCP1 to LCP4
may be disposed between the image source 110 and the reflector 140
to adjust the imaging condition of the virtual image VI for
enhancing the flexibility of the imaging effect.
[0047] In light of the foregoing, the head up display system in
accordance with some embodiments of the disclosure includes an
image adjustment device capable of adjusting the imaging distance
and/or the size of the created virtual image so that the head up
display system have various imaging results to enhance the
flexibility of real use.
[0048] It will be apparent to those skilled in the art that various
modifications and variations can be made to the disclosed
embodiments without departing from the scope or spirit of the
disclosure. In view of the foregoing, it is intended that the
disclosure covers modifications and variations provided that they
fall within the scope of the following claims and their
equivalents.
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