U.S. patent application number 16/528771 was filed with the patent office on 2020-10-15 for system and assembly for controlling temperature in head-up displays.
The applicant listed for this patent is Denso Corporation, DENSO International America, Inc.. Invention is credited to Emma HIGASHIKAWA, Juan MARTINEZ, Yusuke MATSUI, Keitaro YOSHIOKA.
Application Number | 20200326542 16/528771 |
Document ID | / |
Family ID | 1000005117856 |
Filed Date | 2020-10-15 |
United States Patent
Application |
20200326542 |
Kind Code |
A1 |
HIGASHIKAWA; Emma ; et
al. |
October 15, 2020 |
SYSTEM AND ASSEMBLY FOR CONTROLLING TEMPERATURE IN HEAD-UP
DISPLAYS
Abstract
A head-up display (HUD) assembly for a vehicle is provided, A
backlight assembly case is made of a material having a thermal
conductivity exceeding 15 W/mK and an emissivity of at least 0.8. A
light source is provided, A thin film transistor (TFT) panel has a
first axial surface and a second axial surface. A portion of light
emitted from the light source transmits through the TFT panel from
the first axial surface to the second axial surface, and a portion
of the TFT panel is mounted to the backlight assembly case in a
direct face-to-face relationship.
Inventors: |
HIGASHIKAWA; Emma;
(Farmington Hills, MI) ; MARTINEZ; Juan;
(Farmington, MI) ; MATSUI; Yusuke; (West
Bloomfield, MI) ; YOSHIOKA; Keitaro; (Farmington
Hills, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DENSO International America, Inc.
Denso Corporation |
Southfield
Kariya |
MI |
US
JP |
|
|
Family ID: |
1000005117856 |
Appl. No.: |
16/528771 |
Filed: |
August 1, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62831290 |
Apr 9, 2019 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60K 35/00 20130101;
B60K 2370/1529 20190501; G02B 27/0101 20130101; G02B 27/0149
20130101 |
International
Class: |
G02B 27/01 20060101
G02B027/01; B60K 35/00 20060101 B60K035/00 |
Claims
1. A head-up display (HUD) assembly for a vehicle, the HUD assembly
comprising: a backlight assembly case made of a material having a
thermal conductivity exceeding 15 W/mK and an emissivity of at
least 0.8; a light source; and a thin film transistor (TFT) panel
having a first axial surface and a second axial surface, wherein a
portion of light emitted from the light source transmits through
the TFT panel from the first axial surface to the second axial
surface, and wherein a portion of the TFT panel is mounted to the
backlight assembly case in a direct face-to-face relationship;
wherein the backlight assembly case has an end having an
axially-extending portion and an inwardly-extending portion,
wherein the axially-extending portion is in direct face-to-face
contact with a TFT cover attached to the TFT panel, and wherein the
inwardly-extending portion is in direct face-to-face contact with
the first axial surface of the TFT panel.
2. The HUD assembly of claim 1, wherein the first axial surface of
the TFT panel is in direct contact with the backlight assembly case
in a face-to-face relationship.
3. The HUD assembly of claim 2, further comprising a TFT cover
defining an opening aligned with the second axial surface of the
TFT panel, wherein the TFT cover is in direct contact with the
second axial surface of the TFT panel in a face-to-face
relationship.
4. (canceled)
5. The HUD assembly of claim 1, wherein the backlight assembly case
has an interior surface that is black to facilitate heat
absorption.
6. The HUD assembly of claim 1, wherein the backlight assembly case
includes a plurality of fins extending outwardly therefrom to
facilitate radiating heat to an external environment.
7. The HUD assembly of claim 1, wherein the thermal conductivity of
the backlight assembly case is in a range between 15 W/mK and 40
W/mK.
8. The HUD assembly of claim 1, wherein there is no air gap or
insulative material at a contact between the TFT panel and the
backlight assembly case.
9. The HUD assembly of claim 1, further comprising non-optical
components including a lens spacer, wherein the lens spacer is in
direct contact with the backlight assembly case.
10. The HUD assembly of claim 1, further comprising a
thermally-conductive tape adhering the backlight assembly case to
the TFT panel.
11. A head-up display (HUD) assembly for a vehicle, the HUD
assembly comprising: a light source configured to transmit a light;
a pair of lenses configured to distort the light; a lens spacer
connected to and between the pair of lenses to maintain an axial
space between the lenses; a thin film transistor (TFT) panel
configured to receive the light passed through the pair of lenses;
and a backlight assembly case housing the light source, the lenses,
and the spacer, wherein the backlight assembly case is in direct
contact with the TFT panel, and wherein the backlight assembly case
is made of a material having a thermal conductivity exceeding 15
W/mK.
12. The HUD assembly of claim 11, wherein the material of the
backlight assembly case has an emissivity of at least 0.8.
13. The HUD assembly of claim 11, wherein the backlight assembly
case and the spacer are a single integral unit formed from the same
material.
14. The HUD assembly of claim 11, wherein the TFT panel has a first
axial surface and a second axial surface, and wherein the first
axial surface directly contacts the backlight assembly case.
15. The HUD assembly of claim 14, wherein the backlight assembly
case has an end having an axially-extending portion and an
inwardly-extending portion, wherein the inwardly-extending portion
directly contacts the first axial surface in a face-to-face
relationship.
16. The HUD assembly of claim 14, further comprising a TFT cover
secured to the TFT panel, wherein the TFT cover has an
inwardly-extending portion directly contacting the TFT panel in a
face-to-face relationship.
17. The HUD assembly of claim 16, wherein the TFT panel is between
and directly contacts the TFT cover and the backlight assembly
case.
18. A head-up display (HUD) device comprising: a backlight assembly
case; a light source housed within the backlight assembly case; and
a thin-film transistor (TFT) panel configured to receive light
transmitted from the light source, the TFT panel having a first
surface, an opposing second surface, and an outer edge between the
first surface and the second surface; wherein the first surface and
the outer edge directly contact the backlight assembly case to
facilitate heat transfer from the TFT panel to the backlight
assembly case; and wherein the backlight assembly case ends at an
axially-extending portion and an inwardly-extending portion,
wherein the outer edge of the TFT panel directly contacts the
axially-extending portion and the first surface directly contacts
the inwardly-extending portion.
19. (canceled)
20. The HUD device of claim 18, wherein the backlight assembly case
is made of a material having a thermal conductivity exceeding 15
W/mK and an emissivity of at least 0.8.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. provisional
application Ser. No. 62/831,290 filed Apr. 9, 2019, the disclosure
of which is hereby incorporated in its entirety by reference
herein.
TECHNICAL FIELD
[0002] The present disclosure relates to a system and assembly for
controlling temperature of a display in a head-up display.
BACKGROUND
[0003] Various automotive vehicles have a head-up display (HUD)
system. In a HUD system, a light source projects a light, which is
reflected onto a windshield of the vehicle. The focal point of the
light is out beyond the vehicle, enabling the driver of the vehicle
to view the light on the windshield without changing focus while
looking at the outside environment.
SUMMARY
[0004] In one embodiment, a head-up display (HUD) assembly for a
vehicle is provided. A backlight assembly case is made of a
material having a thermal conductivity exceeding 15 W/mK and an
emissivity of at least 0.8. A light source is provided. A thin film
transistor (TFT) panel has a first axial surface and a second axial
surface. A portion of light emitted from the light source transmits
through the TFT panel from the first axial surface to the second
axial surface, and a portion of the TFT panel is mounted to the
backlight assembly case in a direct face-to-face relationship.
[0005] In another embodiment, a HUD assembly for a vehicle is
provided. A light source is configured to transmit a light. A pair
of lenses is configured to distort the light. A spacer is connected
to and between the pair of lenses to maintain a space between the
lenses. A thin film transistor (TFT) panel configured to receive
the light passed through the pair of lenses. A backlight assembly
case houses the light source, the lenses, and the spacer. The
backlight assembly case is in direct contact with the TFT panel,
and the backlight assembly case is made of a material having a
thermal conductivity exceeding 15 W/mK.
[0006] In another embodiment, a HUD device includes a backlight
assembly case, a light source housed within the backlight assembly
case, and a thin-film transistor (TFT) panel configured to receive
light transmitted from the light source. The TFT panel has a first
surface, an opposing second surface, and an outer edge between the
first surface and the second surface. The first surface and the
outer edge directly contact the backlight assembly case to
facilitate heat transfer from the TFT panel to the backlight
assembly case.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 illustrates a side schematic view of a HUD system,
according to one embodiment.
[0008] FIG. 2 illustrates a side perspective view of a HUD
backlight assembly in an assembled state, according to one
embodiment.
[0009] FIG. 3 illustrates an exploded perspective view of the HUD
backlight assembly of FIG. 2, according to one embodiment.
[0010] FIG. 4 illustrates a cross-sectional view of the HUD
backlight assembly of FIG. 2, according to an embodiment.
DETAILED DESCRIPTION
[0011] Embodiments of the present disclosure are described herein.
It is to be understood, however, that the disclosed embodiments are
merely examples and other embodiments can take various and
alternative forms. The figures are not necessarily to scale; some
features could be exaggerated or minimized to show details of
particular components. Therefore, specific structural and
functional details disclosed herein are not to be interpreted as
limiting, but merely as a representative basis for teaching one
skilled in the art to variously employ the embodiments. As those of
ordinary skill in the art will understand, various features
illustrated and described with reference to any one of the figures
can be combined with features illustrated in one or more other
figures to produce embodiments that are not explicitly illustrated
or described. The combinations of features illustrated provide
representative embodiments for typical applications. Various
combinations and modifications of the features consistent with the
teachings of this disclosure, however, could be desired for
particular applications or implementations.
[0012] A head-up display (HUD), also referred to as a heads-up
display, is a type of transparent display that presents data
without requiring the user to look away from the usual environment.
In vehicular applications, data can be presented on the windshield
(for example), in a transparent and visually-unobstructed manner so
that the driver can clearly see the surrounding environment while
driving. Some data available for display on the windshield includes
vehicle speed, turn-by-turn navigation instructions, warnings
regarding surrounding objects, etc.
[0013] FIG. 1 illustrates a general HUD system 10 according to one
embodiment. The HUD system 10 is in a vehicle, such as a car,
truck, sports utility vehicle, van, and the like. The HUD system 10
includes various components beneath the dashboard of the vehicle.
For example, the HUD system 10 can include a projector unit 12. For
simplicity sake, the projector unit 12 is shown herein to have a
light source 14, which can be a light-emitting diode (LED) light
source located at the rear of the projector unit 12, for example.
Light transmitted from the light source 14 is generally shown at
16. The light from the light source 14 is sent to a screen or
visual display, such as thin-film transistor (TFT), in an
embodiment. The TFT can create an image, and the LEDs can light up
the image; in other words, the LEDs can be a backlight for the TFT.
The light can then be reflected off of a mirror 18. The light
reflected off of the mirror 18, shown generally at 20, passes
through an aperture or transparent region of the dashboard and is
reflected off the vehicle windshield 22 to the driver 26. The light
shown on the windshield can be shown over an area 24 of the
windshield that can, for example, overlay with the road ahead of
the driver 26 from the driver's viewpoint.
[0014] While not shown in FIG. 1, the HUD system 10 can include
many other components to aid in. the effective delivery of light to
the windshield, such as collimators, lenses, additional mirrors,
and other structure. While the HUD system 10 may TFT, other screens
or visual displays may be used, such as a liquid crystal display
(LCD), liquid crystal on silicon (LCoS), digital micro-mirrors
(DMDs), organic light-emitting diodes (OLEDs), or others made using
a wide variety of semiconductor materials (e.g., silicon, glass,
cadmium selenide, metal oxides, etc.) which is illuminated by the
light from the light source as the light as it is projected to the
windshield.
[0015] Due to compact designs, packaging constraints, light, and
power consumption, among other factors, a HUD system is a prime
environment for an unwanted increase of heat. If left unaccounted
for, the entire HUD system (including the housing, lenses, TFT
panel, etc.) can increase in heat to an undesirable level, which
could degrade performance of the HUD system.
[0016] Some known concepts to reduce the heat of the HUD system
include placing a mesh screen, polarizer or filter in the light
path that is designed to be hit with the light, and transmit the
heat from the light to the outer case or housing. However, this can
remove some of the intensity of the light that is eventually
intended for traveling to the windshield, and therefore the quality
of the light displayed on the windshield is degraded.
[0017] According to various embodiments described herein, a HUD
system is provided that is specifically tailored for removing heat
from the system, particularly the HUD's display. In one example,
heat conduction takes place with transferring excess heat directly
from the HUD's display via conduction. In another example, heat
absorption takes place by absorbing stray light rays (e.g., light
rays that do not eventually get transferred to the windshield)
within the outer case that would otherwise be absorbed by the
display. These embodiments remove heat away from the display to
prevent overheating of the HUD's display, improving the operability
and efficiency of the display.
[0018] FIG. 2 illustrates a perspective view of a HUD backlight
assembly 30 according to one embodiment. FIG. 3 illustrates an
exploded perspective view of the HUD backlight assembly 30. FIG. 4
illustrates a cross-sectional view of the HUD backlight assembly 30
along line 4-4 in FIG. 2. The HUD backlight assembly 30 can house
the various structures explained above, such as a light source,
mirror(s), collimators, etc.
[0019] Referring to FIGS. 2-4, the HUD backlight assembly 30 (also
referred to as a HUD display assembly) includes an outer housing or
case 32, also referred to as a backlight assembly case. The case
may support a TFT screen or TFT panel 34, if such a screen is
provided in the particular HUD system. The TFT panel 34 is also
assembled to a cover 36, which has a central opening 38 aligned
with the TFT panel 34 such that the illumination of the TFT panel
34 is visible through the opening 38. The orientation and
positioning of the HUD backlight assembly 30 can be such that the
TFT panel 34 is directly aligned with an opening in the dashboard
of the vehicle. A protective, transparent cover (not shown) may be
placed over the opening in the dashboard to protect the TFT panel
34.
[0020] The HUD backlight assembly 30 may also include a light
source 40, such as one described above. In the illustrated
embodiment, the light source 40 is an LED board. A first lens 42
including a plurality of individual lenses arranged on a lens board
are also provided, with each lens aligned with a respective one of
the LEDs, for example. A second lens 44 is also provided, spaced
apart from the first lens 42. A lens spacer 46 may be provided,
attached to both lenses 42, 44 and configured to maintain a special
relationship between the lenses.
[0021] During operation, the nature of the HUD backlight assembly
30 nurtures an environment in which heat can accumulate. The HUD
backlight assembly 30 includes several heat-transferring structural
members. For example, the TFT case 32 can include a plurality of
fins 48 extending vertically from one of the outer surfaces of the
TFT case 32. In the illustrated example, the fins 48 extend from an
upper surface of the case, toward the overlying dash of the
vehicle. As heat rises from the HUD backlight assembly 30, the heat
can. dissipate to the environment from the fins 48.
[0022] The HUD backlight assembly 30 is also provided with a heat
sink 50 at a rear of the assembly. The heat sink 50 can be attached
directly to the TFT case 32. For example, a plurality of fasteners
(e.g., screws, bolts, etc.) 52 can extend through. apertures of the
heat sink 50 to connect to corresponding holes in a board of the
light source 40 to connect the two. Heat generated by, the light
source 40 can be transmitted to the heat sink 50 whereupon the heat
is dissipated to the surrounding environment. The heat sink 50 can
also have one or more fins 56 extending upwardly therefrom to
further transfer the heat similar to the fins 48 of the TFT case
32. Apertures may also exist in flanges 54 extending from side
surfaces of the TFT case 32 for other fasteners (not shown) if
desired to mount the HUD backlight assembly 30.
[0023] While the fins 48, 56 as well as the heat sink 50 aid in
removing heat from the HUD backlight assembly 30, the TFT panel 34
is specifically susceptible for localized increases in heat. As
light is transmitted from the light source 40 to the TFT panel 34,
the light disperses across the screen; heat is a byproduct. The
assembly disclosed herein can reduce and remove the heat contained
on the TFT panel 34 in a number of additional ways, including
conducting the heat as well as absorbing the heat.
[0024] In one embodiment, heat is absorbed within the HUD backlight
assembly 30 away from the TFT panel 34. This can be done with a
direct mounting of the TFT panel 34 to the TFT case 32. As can be
seen in FIG. 4, the TFT panel 34 can be directly connected to and
between the TFT case 32 and the TFT cover 36. In one embodiment,
the TFT case 32 includes an L-shaped end having an
axially-extending portion 60 extending toward the TFT cover 36, and
an inwardly-extending portion 62 extending toward the inner region
of the TFT case 32. The TFT panel 34 or screen can be in direct
contact with one or both of these portions 60, 62 of the TFT case
32. An axial surface of the TFT panel 34 can be in a direct
face-to-the contact with. the inwardly-extending portion 62. Also,
an outer edge of the TFT panel 34 (e.g., facing away from the
interior) can be in a direct face-to-face contact with the
axially-extending portion 60.
[0025] Likewise, the TFT cover 36 can have an L-shaped end having
an axially-extending portion 64 extending toward the TFT case 32,
and an inwardly-extending portion 66 extending toward the opening
38. The TFT panel 34 or screen can be in direct contact with one or
both of these portions 64, 66 of the TFT cover 36. In the
illustrated embodiment, an axial surface of the TFT panel 34 can be
in direct face-to-face contact with the inwardly-extending portion
66. The axially-extending portion 64 can be in a direct
face-to-face contact and overlapping the axially-extending portion
60 of the TFT case 32.
[0026] Several direct contacts are made as shown in FIG. 4. The TFT
panel 34 may include a first axial. surface (e.g., facing inward
toward the interior surface of the TFT case 32) and a second axial
surface (e.g., facing outward away from the interior surface of the
TFT case 32). The first axial surface may be in direct face-to-face
contact with the inwardly-extending portion 62 of the TFT case 32.
The second axial surface may be in direct face-to-face contact with
the inwardly-extending, portion 66 of the TFT cover 36. Moreover,
the outer edge of the TFT panel 34 (e.g., the outer edge facing
upward and away from a center point of the TFT panel 34) can be in
direct face-to-face contact with the axially-extending portion 60
of the TFT case 32. And, the axially-extending portion 60 of the
TFT case 32 may be in direct face-to-face contact with the
axially-extending portion 64 of the TFT cover 36.
[0027] The direct face-to-face contacts between the TFT panel 34
and either or both of the TFT cover 36 and TFT case 32 increases
heat conducted between the components. Heat transmitted and
contained in the TFT panel during operation can be dispersed via
the conduction, where it can he dissipated into the environment via
the fins 48 explained above, for example. This provides an improved
ability to remove heat from the TFT panel 34 than, for example, an
air gap located axially between the TFT panel and either or both of
the TFT cover 36 and TFT case 32, as heat may not transfer
adequately enough across the air gap. Thermally-conductive tape or
adhesive can be used at or along at least a portion of the
face-to-face connections explained above to facilitate the heat
conduction.
[0028] In one embodiment, heat is absorbed within the TFT case 32.
As light travels from the light source 40, stray light (e.g., light
that is produced by the light source 40 but does not make it to the
TFT panel 34) can bounce around the interior surfaces of the TFT
case 32. Also, the stray light may, after bouncing within the TFT
case 32, be absorbed by the TFT panel 34, increasing the heat of
the TFT panel 34. Absorbing as much of the stray light as possible
before it reaches the TFT panel 34 can aid in reducing the
temperature rise of the TFT panel 34. The TFT case 32 may therefore
be made of a material that is colored black or a similar dark
shade. This facilitates the TFT case 32--rather than the TFT panel
34--to absorb the heat produced by stray light.
[0029] Moreover, in HUD systems where non-optical structural
components (such as the lens spacer 46 for example) surround the
optical path, such structural components will absorb stray light
instead of the TFT case 32. Thus, it can be beneficial for the heat
of the stray light to be indirectly transferred to the TFT case 32
through the non-optical structural components. Therefore, in some
embodiments, such components are made from materials that readily
absorb light and exhibit high conductivity. For example, the lens
spacer 46, the TFT case 32, etc can be made of a
thermally-conductive plastic, having a thermal conductivity in the
range of 1 W/mK to 40 W/mK, and more particularly between 15 W/mK
and 40 W/mK, which is anywhere from 5 to 500 times the amount of
thermal conductivity in conventional plastics.
[0030] In order to facilitate the heat transfer to the TFT case 32
effectively, the non-optical structural components and the TFT case
32 can be in direct physical contact with each other. The
components can be adhered via a thermally-conductive tape. In
another embodiment the TFT case 32 and the non-optical structural
components (e.g., lens spacer 46) are molded as a single part
created from the same material.
[0031] As explained above, heat is collected at the TFT case 32 in
two different modes absorption and conduction. For example, heat
from stray light can be absorbed by the TFT case 32 and the
non-optical structure. And, heat can be conducted via physical
contact into the TFT case 32. Heat collected by these two modes can
then be released to the external environment via radiation, for
example, facilitated by the use of a high emissivity material, In
order to realize sufficiently high conductivity and high emissivity
characteristics, the TFT case 32 can be made of a material (e.g.,
plastic or metal) with an emissivity greater than 0.8 and a
conductivity greater than 15 W/mK. Furthermore, parts surrounding
the optical path within the TFT case 32 (such as the lens spacer
46, frame of the lens 44, etc.) can be constructed with a black or
dark colored material to absorb the stray light. The parts can be
molded from black plastic, or painted with black pigment. And, as
explained above, fins 48 can also be utilized to aid in releasing,
the heat to the external environment. via radiation.
[0032] While exemplary embodiments are described above, it is not
intended that these embodiments describe all possible forms
encompassed by the claims. The words used in the specification are
words of description rather than limitation, and it is understood
that various changes can be made without departing from the spirit
and scope of the disclosure. As previously described, the features
of various embodiments can be combined to form further embodiments
of the invention that may not be explicitly described or
illustrated. While various embodiments could have been described as
providing advantages or being preferred over other embodiments or
prior art implementations with respect to one or more desired
characteristics, those of ordinary skill in the art recognize that
one or more features or characteristics can. be compromised to
achieve desired overall system attributes, which depend on the
specific application and implementation. These attributes can
include, but are not limited to cost, strength, durability, life
cycle cost, marketability, appearance, packaging, size,
serviceability, weight, manufacturability, ease of assembly, etc,
As such, to the extent any embodiments are described as less
desirable than other embodiments or prior art implementations with
respect to one or more characteristics, these embodiments are not
outside the scope of the disclosure and can be desirable for
particular applications.
* * * * *