U.S. patent application number 14/791268 was filed with the patent office on 2016-05-26 for light source module and light source unit.
The applicant listed for this patent is Young Lighting Technology Inc.. Invention is credited to Chi-Lun Chen, Hsin-Hung Lee, Chiao-Chih Yang, Fang-Ju Yeh.
Application Number | 20160146430 14/791268 |
Document ID | / |
Family ID | 56009818 |
Filed Date | 2016-05-26 |
United States Patent
Application |
20160146430 |
Kind Code |
A1 |
Yeh; Fang-Ju ; et
al. |
May 26, 2016 |
LIGHT SOURCE MODULE AND LIGHT SOURCE UNIT
Abstract
A light source module including at least one optical film and a
light source unit is provided. The light source unit is disposed
under the at least one optical film, and a space is formed between
the light source unit and the at least one optical film. The light
source unit includes a plurality of light emitting elements and a
plurality of secondary lenses. The light emitting elements are
arranged along a direction parallel to the at least one optical
film. The secondary lenses are correspondingly disposed on the
light emitting elements and each of the secondary lenses has a
patterned reflective layer. Each of the secondary lenses has a
light hole radius R, a distance between a distribution range of the
patterned reflective layer and a bottom of the corresponding
secondary lenses is H, and the distribution range of the patterned
reflective layer satisfies 1/R<H<3/2R.
Inventors: |
Yeh; Fang-Ju; (Hsin-Chu,
TW) ; Yang; Chiao-Chih; (Hsin-Chu, TW) ; Lee;
Hsin-Hung; (Hsin-Chu, TW) ; Chen; Chi-Lun;
(Hsin-Chu, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Young Lighting Technology Inc. |
Hsin-Chu |
|
TW |
|
|
Family ID: |
56009818 |
Appl. No.: |
14/791268 |
Filed: |
July 3, 2015 |
Current U.S.
Class: |
362/308 ;
362/296.05; 362/307 |
Current CPC
Class: |
G02F 2001/133607
20130101; G02F 1/133603 20130101; G02B 19/0061 20130101; G02F
1/133605 20130101; G02B 19/0028 20130101 |
International
Class: |
F21V 7/04 20060101
F21V007/04; F21V 5/04 20060101 F21V005/04 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 25, 2014 |
TW |
103140771 |
Claims
1. A light source module, comprising: at least one optical film;
and a light source unit, disposed under the at least one optical
film, a space being formed between the light source unit and the at
least one optical film, and the light source unit comprising: a
plurality of light emitting elements, arranged along a direction
parallel to the at least one optical film; and a plurality of
secondary lenses, correspondingly disposed on the light emitting
elements, and each of the secondary lenses having a patterned
reflective layer, wherein each of the secondary lenses has a light
hole radius R, a distance between a distribution range of the
patterned reflective layer and a bottom of the corresponding
secondary lens is H, and the distribution range of the patterned
reflective layer satisfies 1/3R<H<3/2R.
2. The light source module of claim 1, wherein each of the
secondary lenses is a refractive secondary lens, and the patterned
reflective layer is disposed on a circumference of an upper surface
of the corresponding secondary lens.
3. The light source module of claim 2, wherein the distribution
range of the patterned reflective layer satisfies
1/3R<H<R.
4. The light source module of claim 2, wherein a distance between
the distribution range of the patterned reflective layer and a
center of the corresponding secondary lens is X, and the
distribution range of the patterned reflective layer satisfies
4/5R<X<R.
5. The light source module of claim 2, wherein a shape of the
patterned reflective layer is a ring shape.
6. The light source module of claim 2, wherein the patterned
reflective layer has a plurality of openings.
7. The light source module of claim 2, wherein the patterned
reflective layer has a plurality of irregular patterns, and the
irregular patterns are arranged in a manner of surrounding the
center of the corresponding secondary lens.
8. The light source module of claim 1, wherein each of the
secondary lenses is a reflective secondary lens, and the patterned
reflective layer covers an upper surface of the corresponding
secondary lens.
9. The light source module of claim 8, wherein the distribution
range of the patterned reflective layer satisfies
1/2R<H<3/2R.
10. The light source module of claim 8, wherein the patterned
reflective layer is distributed in a range within 2R away from the
center of the corresponding secondary lens.
11. The light source module of claim 8, wherein the patterned
reflective layer is flexible.
12. The light source module of claim 8, wherein the patterned
reflective layer has at least one opening, and a ratio of an area
of the at least one opening to a surface area of the patterned
reflective layer is between 20% and 90%.
13. The light source module of claim 12, wherein a number of the at
least one opening of the patterned reflective layer is plural, and
the openings are arranged in a manner of circular symmetry.
14. The light source module of claim 12, wherein a number of the at
least one opening of the patterned reflective layer is plural, and
the openings are irregularly arranged.
15. The light source module of claim 1, wherein a reflective index
of the patterned reflective layer is between 50% and 100%.
16. The light source module of claim 1, wherein the patterned
reflective layer is a white reflective layer, a silver reflective
layer, an evaporated reflective metal or an ink reflective
material.
17. The light source module of claim 1, further comprising: a
diffusion plate, located between the at least one optical film and
the light source unit.
18. A light source unit, comprising: a light emitting element; and
a secondary lens, correspondingly disposed on the light emitting
element, and the secondary lens has a patterned reflective layer,
wherein the secondary lens has a light hole radius R, a distance
between a distribution range of the patterned reflective layer and
a bottom of the secondary lens is H, and the distribution range of
the patterned reflective layer satisfies 1/3R<H<3/2R.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of Taiwan
application serial no. 103140771, filed on Nov. 25, 2014. 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
[0002] 1. Field of the Invention
[0003] The invention relates to a light source module and a light
source unit, and more particularly, relates to a light source
module and a light source unit having a secondary lens.
[0004] 2. Description of Related Art
[0005] Generally, a light emitting diode (LED) is applicable on
various lighting devices and various flat-panel displays (e.g., as
a light source of a liquid crystal display (LCD)) in daily
life.
[0006] Take the light emitting diode applied in the liquid crystal
display for example. A backlight module of the liquid crystal
display is a kind of a planer light source, and a basic principle
thereof is to convert an effective light from a linear light source
or a point light source into the planar light source with high
brightness and favorable uniformity. Generally, according to a
position of the light source, the backlight module may be
classified into two types, namely a edge type and a direct type.
Because a direct type backlight module has a simple structure and
may adopt a plurality of light sources for providing higher
brightness and luminance, the direct type backlight module is often
applied in electronic products such as a large size liquid crystal
display.
[0007] In order to reduce the number of the light emitting diodes
or reduce an optical cavity depth, secondary optical lenses are
often disposed in some of the direct type backlight modules
nowadays. However, a light diffusion capability of the secondary
optical lens, the number of the light emitting diodes and the
optical cavity depth are factors that affect the product costs. For
instance, when the secondary lens used in the direct type backlight
module is a refractive secondary lens, which has an opening angle
of .+-.80.degree. and a distance ratio (i.e., h/p ratio) of an
optical cavity depth (h, referring to FIG. 1) to a pitch between
the light emitting diodes (p, referring to FIG. 1) approximately
0.25, if the optical cavity depth is 25 mm, the pitch between the
light emitting diodes requires approximately 100 mm. As the
distance ratio of the optical cavity depth to the pitch between the
light emitting diodes is lower, the better light diffusion
capability of the secondary lens is required. Therefore, when
aforesaid secondary lens is used and the direct type backlight
module are to be further miniaturized, in order to maintain the
same distance ratio of the optical cavity depth to the pitch
between the light emitting diodes, the pitch between the light
emitting diodes must be reduced. Accordingly, the number of the
light emitting diodes and processing costs for attaching the
secondary lens to surfaces of supporting the secondary lens may
both be increased. As such, how to provide a favorable uniformity
and taste for the direct type backlight module while taking the
product costs into consideration is an issue to be solved.
[0008] China patent application publication no. CN101153982A
discloses a backlight module having a bottom plate, a plurality of
light emitting diodes disposed on the bottom plate, and an optical
plate disposed above the light emitting diodes. Taiwan patent
application publication no. 201411892 discloses a lens and a
reflective layer. The lens is disposed on a substrate and covers a
light emitting diode chip. The reflective layer is disposed on the
lens, and configured to reflect a light ray emitted from a lateral
side of the light emitting diode chip. Taiwan patent application
publication no. 201027184 discloses a backlight module including a
reflective plate, at least one light source and at least one lens.
U.S. Pat. No. 6,814,456B1 discloses a light shading sheet, which
covers a light source generator, and the light shading sheet
includes a plurality of light holes for scattering light.
[0009] The information disclosed in this "BACKGROUND OF THE
INVENTION" section is only for enhancement understanding of the
background of the invention 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. Furthermore, the
information disclosed in this "BACKGROUND OF THE INVENTION" section
does not mean that one or more problems to be solved by one or more
embodiments of the invention was acknowledged by a person of
ordinary skill in the art.
SUMMARY OF THE INVENTION
[0010] The invention is directed to a light source module including
advantages of low costs, thin optical cavity and high
uniformity.
[0011] The invention provides a light source unit having an
advantage of high uniformity.
[0012] Other objects and advantages of the invention can be further
illustrated by the technical features broadly embodied and
described as follows.
[0013] In order to achieve one or a portion of or all of the
objects or other objects, a light source module is proposed
according to an embodiment of the invention. The light source
module includes at least one optical film and a light source unit.
The light source unit is disposed under the at least one optical
film, and a space is formed between the light source unit and the
at least one optical film. The light source unit includes a
plurality of light emitting elements and a plurality of secondary
lenses. The light emitting elements are arranged along a direction
parallel to the at least one optical film. The secondary lenses are
correspondingly disposed on the light emitting elements and each of
the secondary lenses has a patterned reflective layer. Each of the
secondary lenses has a light hole radius R, a distance between a
distribution range of the patterned reflective layer and a bottom
of each of the secondary lenses is H, and the distribution range of
the patterned reflective layer satisfies 1/3R<H<3/2R.
[0014] In order to achieve one or a part of or all of the above
advantages or other advantages, a light source unit including a
light emitting element and a secondary lens is proposed according
to an embodiment of the invention. The secondary lens is
correspondingly disposed on the light emitting element. The
secondary lens has a patterned reflective layer. The secondary lens
has a light hole radius R, a distance between a distribution range
of the patterned reflective layer and a bottom of the secondary
lens is H, and the distribution range of the patterned reflective
layer satisfies 1/3R<H<3/2R.
[0015] In an embodiment of the invention, each of the secondary
lenses is a refractive secondary lens, and the patterned reflective
layer is disposed on a circumference of an upper surface of the
corresponding secondary lens.
[0016] In an embodiment of the invention, the distribution range of
the patterned reflective layer satisfies 1/3R<H<R.
[0017] In an embodiment of the invention, a distance between the
distribution range of the patterned reflective layer and a center
of the corresponding secondary lens is X, and the distribution
range of the patterned reflective layer satisfies
4/5R<X<R.
[0018] In an embodiment of the invention, a shape of the patterned
reflective layer is a ring shape.
[0019] In an embodiment of the invention, the patterned reflective
layer has a plurality of openings.
[0020] In an embodiment of the invention, the patterned reflective
layer has a plurality of irregular patterns, and the irregular
patterns are arranged in a manner of surrounding the center of the
corresponding secondary lens.
[0021] In an embodiment of the invention, each of the secondary
lenses is a reflective secondary lens, and the patterned reflective
layer covers an upper surface of the corresponding secondary
lens.
[0022] In an embodiment of the invention, the distribution range of
the patterned reflective layer satisfies 1/2R<H<3/2R.
[0023] In an embodiment of the invention, the patterned reflective
layer is distributed in a range within 2R away from the center of
the corresponding secondary lens.
[0024] In an embodiment of the invention, the patterned reflective
layer is flexible.
[0025] In an embodiment of the invention, the patterned reflective
layer has at least one opening, and a ratio of an area of the at
least one opening to a surface area of the patterned reflective
layer is between 20% and 90%.
[0026] In an embodiment of the invention, a number of the at least
one opening of the patterned reflective layer is plural, and the
openings are arranged in a manner of circular symmetry.
[0027] In an embodiment of the invention, a number of the at least
one opening of the patterned reflective layer is plural, and the
openings are irregularly arranged.
[0028] In an embodiment of the invention, a reflective index of the
patterned reflective layer is between 50% and 100%.
[0029] In an embodiment of the invention, the patterned reflective
layer is a white reflective layer, a silver reflective layer, an
evaporated reflective metal or an ink reflective material.
[0030] In an embodiment of the invention, the light source module
further includes a diffusion plate located between the at least one
optical film and the light source unit.
[0031] The embodiments of the invention may achieve at least one of
advantages or effects as listed below. By disposing the secondary
lens and the patterned reflective layer, the embodiments of the
invention may compensate the distribution of the light shape,
improve the uniformity for illuminating and reduce a required depth
for the optical cavity for thinning of the light source module. In
addition, because a volume of the light source module is
miniaturized, a cost for the components therein may be reduced.
Moreover, while improving the uniformity on the illuminating
surface, degrees of freedom for selecting various parts such as the
optical film, the diffusion plate, the light emitting element are
increased accordingly, so as to further improve the flexibility
when performing related optical designs.
[0032] Other objectives, features and advantages of the present
invention will be further understood from the further technological
features disclosed by the embodiments of the present 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.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] 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.
[0034] FIG. 1 is a cross-sectional view illustrating a light source
module according to an embodiment of the invention.
[0035] FIG. 2A is a cross-sectional view illustrating the light
source unit of FIG. 1.
[0036] FIG. 2B is a data simulating diagram of lighting
distribution curves for the different secondary lenses in the light
source module of FIG. 1.
[0037] FIG. 3A to FIG. 3C are top views respectively illustrating
the different patterned reflective layers of FIG. 1.
[0038] FIG. 4 is a cross-sectional view illustrating a light source
module according to another embodiment of the invention.
[0039] FIG. 5 is a cross-sectional view illustrating the light
source unit of FIG. 4.
[0040] FIG. 6A to FIG. 6B are top views respectively illustrating
the different patterned reflective layers of FIG. 4.
DESCRIPTION OF THE EMBODIMENTS
[0041] 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 present
invention can 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 present 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.
[0042] FIG. 1 is a cross-sectional view illustrating a light source
module according to an embodiment of the invention. Referring to
FIG. 1, a light source module 100 of the present embodiment
includes at least one optical film 110 (three optical films are
exemplarily illustrated in FIG. 1), a light source unit 120, and a
reflecting unit 140. The light source unit 120 includes a plurality
of light emitting elements 121 and a plurality of secondary lenses
122, however, the invention is not limited thereto, and in other
embodiments, the light source unit 120 may include one light
emitting element 121 and one secondary lens 122. In the present
embodiment, the light emitting element 121 is, for example, a light
emitting diode (LED), the light source module 100 is, for example,
a direct type backlight module, and the reflecting unit 140 is, for
example, a white reflecting sheet. In one embodiment, the light
source module 100 may further include a diffusion plate 130.
[0043] As shown in FIG. 1, in the present embodiment, the light
emitting element 121 is disposed on a bottom of the light source
module 100, and the light emitting element 121 is disposed, for
example, on a substrate (not marked). The substrate is, for
example, a circuit board. The secondary lenses 122 are
correspondingly disposed on the light emitting elements 121 and the
reflecting unit 140 is disposed on the substrate. The light
emitting elements 121 are arranged along a direction D1 parallel to
the at least one optical film 110. The reflecting unit 140 includes
a plurality of holes HO arranged along the direction D1, and the
positions of the holes HO are corresponding to each of the light
emitting elements 121 and each of the secondary lenses 122 in order
to expose each of the light emitting elements 121 and each of the
secondary lenses 122. In the present embodiment, each of the
secondary lenses 122 is a refractive secondary lens. Generally, the
refractive secondary lens may refract an incident light beam twice
to generate an emergent light beam with large angle variation, so
as to increase a degree of light beam diffusion. In other words,
the refractive secondary lens generally provides the maximum value
of illumination at an opening angle of .+-.75.degree. to
.+-.80.degree. (i.e., a maximum brightness is provided at the
opening angle of .+-.75.degree. to).+-.80.degree.. It is defined
that 0.degree. of the opening angle is at a direction perpendicular
to the direction D1 and .+-.90.degree. of the opening angle is at a
direction parallel to the direction D1. However, while the light
beam is expanded in large angle to obtain wider opening angle for
the conventional refractive secondary lens, a center brightness may
be suppressed accordingly. As a result, when the light source
module 100 has a lower optical cavity, an issue of a center dim
spot may arise due to insufficient distance for mixing the light
beam. Methods regarding how to dispose a patterned reflective layer
PR on an upper surface 122a of the secondary lens 122 in the light
source module 100 of the present embodiment in order to accomplish
means for compensating a light shape are described below with
reference to FIG. 2A.
[0044] FIG. 2A is a cross-sectional view illustrating the light
source unit of FIG. 1. Referring to FIG. 2A, in the present
embodiment, each of the secondary lenses 122 has the patterned
reflective layer PR, and the patterned reflective layer PR is
disposed on a circumference of the upper surface 122a of each of
the secondary lenses 122. The patterned reflective layer PR may be,
for example, a white reflective layer or a silver reflective layer
and is, for example, adhered on the upper surface 122a of each of
the secondary lenses 122. A material of the white reflective layer
may be a titanium dioxide (TiO.sub.2) or a barium sulfate
(BaSO.sub.4), but the invention is not limited thereto. In other
embodiments, a material of the patterned reflective layer PR may be
an evaporated reflective metal (e.g., silver, aluminum, etc.) or an
ink reflective material, and may be formed on the upper surface
122a of each of the secondary lenses 122 through manufacturing
processes such as vapor deposition, an ink jet process or a
printing process. In one embodiment, a reflective index of the
patterned reflective layer PR is exemplarily between 50% and 100%.
It should be noted that, aforesaid numerical range is used only for
example instead of limiting the invention.
[0045] As shown in FIG. 2A, in the present embodiment, each of the
secondary lenses 122 has a light hole radius R. The light hole
radius R is defined as a radius of the upper surface 122a
(illuminating surface) of the secondary lens 122, namely, a half of
a length of the upper surface 122a projected on the optical film
110 (referring to FIG. 1) and parallel to the direction D1. A
distance between a distribution range of the patterned reflective
layer PR and a bottom 122b of each of the secondary lenses 122 is
H, and the distribution range of the patterned reflective layer PR
satisfies 1/3R<H<3/2R. In one embodiment, distances from two
ends of the patterned reflective layer PR to a bottom 122b are a
distance H1 and a distance H2, respectively, wherein the distance
H1 is equal to 1/3R for example, and the distance H2 is equal to R
for example. As such, the distribution range of the patterned
reflective layer PR satisfies 1/3R<H<R. In one embodiment, a
distance between the distribution range of the patterned reflective
layer PR and a center M of each of the secondary lenses 122 is X,
and the distribution range of the patterned reflective layer PR
satisfies 4/5R<X<R. As shown in FIG. 2A, in one embodiment,
distances from two ends of the patterned reflective layer PR to a
center M are a distance X1 and a distance X2, respectively, wherein
the distance X1 is equal to 4/5R for example, and the distance X2
is less than R for example. As such, the distribution range of the
patterned reflective layer PR satisfies 4/5R<X<R. Therefore,
the distribution range of the patterned reflective layer PR may be
related to the size of the patterned reflective layer PR, the size
of the upper surface 122a of the patterned reflective layer PR, and
its position on the upper surface 122a of the secondary lens 122
with respect to the center M of the patterned reflective layer PR
and/or the bottom 122b of the patterned reflective layer PR. In one
embodiment, if the patterned reflective layer PR is in the form of
a ring type (as shown in FIG. 3A or FIG. 3B) or is arranged in a
ring-like type (as shown in FIG. 3C), the two ends of the patterned
reflective layer PR mentioned above are referred to the inner edge
and outer edge. In one embodiment, a size of the light hole radius
R is between 7.5 mm and 8.5 mm for example, and a size of the
distance H between the distribution range of the patterned
reflective layer PR and the bottom 122b of each of the secondary
lenses 122 is between 6 mm and 8 mm for example. It should be noted
that, aforesaid numerical range is used only for example instead of
limiting the invention.
[0046] Accordingly, parts of the light beam in large angle that is
close to edges of the secondary lens 122 may be reflected by the
patterned reflective layer PR, and then recycled back to center M
of the secondary lens 122 for illuminating, so as to effectively
compensate the distribution of the light shape in order to solve
the issue of the center dim spot. Take the 32-inch light source
module 100 adopting the same secondary lens 122 for example. Before
the patterned reflective layer PR of the present embodiment is
disposed, a light diffusion capability of the adopted secondary
lens 122 provides a distance ratio (h/p ratio) of an optical cavity
depth h to a pitch p between the light emitting elements 121 being
approximately 0.25. That is, in the condition where the pitch p
between the light emitting elements 121 is 85 mm, the reasonable
optical cavity depth h should be 21.25 mm. When the patterned
reflective layer PR of the present embodiment is disposed, the
optical cavity depth h may be reduced to 18 mm. That is, the light
diffusion capability of the secondary lens 122 may be improved by
disposing the patterned reflective layer PR, such that the distance
ratio of the optical cavity depth h to the pitch p between the
light emitting elements 121 may be reduced to 0.21. It should be
noted that, aforesaid numerical range is used only for example
instead of limiting the invention.
[0047] As shown in FIG. 2B, a lighting distribution curve C1
represents the secondary lens 122 not disposed with the patterned
reflective layer PR and capable of providing the distance ratio of
the optical cavity depth h to the pitch p between the light
emitting elements 121 being approximately 0.25; a lighting
distribution curve C2 represents the secondary lens 122 disposed
with the patterned reflective layer PR and capable of providing the
distance ratio of the optical cavity depth h to the pitch p between
the light emitting elements 121 being approximately 0.25; and a
lighting distribution curve C3 represents another secondary lens
not disposed with the patterned reflective layer PR and capable of
providing the distance ratio of the optical cavity depth h to the
pitch p between the light emitting elements 121 being approximately
0.30. In comparison with the lighting distribution curve C1 of the
secondary lens 122 not disposed with the patterned reflective layer
PR, the lighting distribution curve C2 of the secondary lens 122
disposed with the patterned reflective layer PR has a higher center
brightness to effectively compensate the distribution of the light
shape. Further, in comparison with the lighting distribution curve
C3 of the another secondary lens not disposed with the patterned
reflective layer PR and capable of providing the distance ratio of
the optical cavity depth h to the pitch p between the light
emitting elements 121 being approximately 0.3, the lighting
distribution curve C2 of the secondary lens 122 disposed with the
patterned reflective layer PR can still maintain a sharp curve for
the distribution of the light shape in large angle, such that most
of the light beam may be emitted in large angle. It should be noted
that, aforesaid numerical range is used only for example instead of
limiting the invention.
[0048] Referring back to FIG. 1, the light source unit 120 is
disposed under the at least one optical film 110, and a space is
formed between the at least one optical film 110 and the reflecting
unit 140 to form an optical cavity of the light source module 100.
In addition, a diffusion plate 130 is located between the at least
one optical film 110 and the light source unit 120.
[0049] Referring to FIG. 1, in one embodiment, the reflecting unit
140 and the diffusion plate 130 are disposed on a transmitting path
of the light beam from the light source unit 120, and the light
source units 120 are distributed on one side of the diffusion plate
130 (i.e. the light source units 120 are disposed under the
diffusion plate 130). Specifically, when the light beam is emitted
from the secondary lens 122, the light beam is transmitted to the
diffusion plate 130. When the light beam is transmitted to the
diffusion plate 130, the light source module 100 may uniform the
distribution of light beams through the diffusion plate 130, and
adjust an illuminating direction through the optical film 110, so
as to enhance a forward luminance of the light source module
100.
[0050] Accordingly, by disposing the secondary lens 122 and the
patterned reflective layer PR, the embodiments may compensate the
distribution of the light shape, improve the uniformity for
illuminating and reduce a required depth for the optical cavity for
thinning of the light source module 100. In addition, because a
volume of the light source module 100 is miniaturized, costs for
mechanical members may be reduced accordingly. Moreover, while
improving the uniformity on the illuminating surface, degrees of
freedom for selecting various parts such as the optical film 110,
the diffusion plate 130 and the light emitting element 121 may
increase accordingly, so as to further improve the flexibility when
performing related optical designs.
[0051] Embodiments regarding shapes of the patterned reflective
layer PR are described below with reference to FIG. 3A to FIG.
3C.
[0052] FIG. 3A to FIG. 3C are top views respectively illustrating
the different patterned reflective layers of FIG. 1. For instance,
as shown in FIG. 3A, in the present embodiment, a shape of the
patterned reflective layer PR may be a ring shape. In other
embodiments, the patterned reflective layer PR may include a
plurality of openings CA (as shown in FIG. 3B), or include a
plurality of irregular patterns RP. The irregular patterns RP are
arranged in a manner of surrounding the center of the secondary
lens 122 (as shown in FIG. 3C), however, the invention is not
limited thereto. Persons of ordinary skill in the art may adopt the
patterned reflective layer PR with suitable patterns based on
actual requirements (e.g., simplifying the manufacturing process),
which are omitted hereinafter.
[0053] FIG. 4 is a cross-sectional view illustrating a light source
module according to another embodiment of the invention. FIG. 5 is
a cross-sectional view illustrating the light source unit of FIG.
4. Referring to FIG. 4 and FIG. 5, a light source module 400 and a
secondary lens 422 of the present embodiment are similar to the
light source module 100 and the secondary lens 122 of FIG. 1, and
their differences are described as follows. In the present
embodiment, each of the secondary lenses 422 of a light source unit
420 is a reflective secondary lens. Generally, the reflective
secondary lens achieves the purpose of expanding the angle for the
emergent light by utilizing a total reflection of the incident
light beam in the reflective secondary lens. In other words, the
reflective secondary lens generally provides the maximum value of
illumination at an opening angle of .+-.80.degree. to
.+-.100.degree., especially it may provide more than 50% brightness
at an opening angle of .+-.90.degree.. However, a part of the light
beam in the emergent light emerges from a horizontal side of the
secondary lens in larger angle. When a stray light is reflected
back to a center of the secondary lens 422, a bright spot
phenomenon is likely to occur at the center of the secondary lens.
Methods regarding how to dispose the patterned reflective layer PR
on an upper surface 422a of the secondary lens 422 in the light
source module 400 of the present embodiment in order to compensate
a light shape are described as follows.
[0054] Take one of secondary lenses 422 as illustration. As shown
in FIG. 5, the patterned reflective layer PR covers the upper
surface 422a of each of the secondary lenses 422. The patterned
reflective layer PR is flexible, such that a lateral side S of the
patterned reflective layer PR may be bent downwardly or bent
upwardly. The light shape of the light emitting element 121
reflected by the secondary lens 422 may be distributed differently
in horizontal or vertical directions. Therefore, by adjusting the
lateral side S of the patterned reflective layer PR to reflect the
light beams from different directions, the light shape in the
horizontal or vertical directions may be adjusted in order to
obtain the desired light shape.
[0055] As shown in FIG. 5, in the present embodiment, a distance
between a distribution range of the patterned reflective layer PR
and a bottom 422b of each of the secondary lenses 422 is H and the
distribution range of the patterned reflective layer PR satisfies
1/3R<H<3/2R. As shown in FIG. 5, in the present embodiment,
distances from two ends (e.g. the end of the lateral side S and the
top surface of the patterned reflective layer PR respectively) of
the patterned reflective layer PR to a bottom 422b are a distance
H3 and a distance H4, respectively, wherein the distance H3 is
equal to 1/2R for example, and the distance H4 is equal to 3/2R for
example. As such, the distribution range of the patterned
reflective layer PR satisfies 1/2R<H<3/2R. Further, in one
embodiment, the patterned reflective layer PR is distributed in a
range within 2R away from the center M of the secondary lens 422.
In one embodiment, a size of the light hole radius R is between 6
mm and 8.5 mm for example, and a size of the distance H between the
distribution range of the patterned reflective layer PR and the
bottom 422b of the secondary lens 422 is between 6 mm and 8 mm for
example. It should be noted that, aforesaid numerical range is used
only for example instead of limiting the invention.
[0056] Accordingly, the uniformity for illuminating may be
effectively improved and a required depth for the optical cavity
may be reduced for thinning of the light source module. For
instance, take the light source module 400 which adopts the
reflective secondary lens 422 with the optical cavity of 15 mm for
example, when the optical cavity depth is reduced to 12.5 mm, the
bright spot would occur. After the patterned reflective layer PR of
the present embodiment is disposed, the uniformity for illuminating
may be effectively improved to eliminate the bright spot.
[0057] FIG. 6A and FIG. 6B are top views respectively illustrating
the different patterned reflective layers of FIG. 4. In the present
embodiment, the patterned reflective layer PR has at least one
opening CA, and a ratio of an area of the at least one opening CA
to a surface area of the patterned reflective layer PR is between
20% and 90%. As shown in FIG. 6A, in the present embodiment, the
number of the at least one opening CA of the patterned reflective
layer PR is plural (two openings CA are illustrated in FIG. 6A for
example), and the openings CA are arranged in a manner of circular
symmetry, but the invention is not limited thereto. In other
embodiments, the openings CA of the patterned reflective layer PR
may be irregularly arranged (as shown in FIG. 6B). Persons of
ordinary skill in the art may adopt the patterned reflective layer
PR with suitable patterns based on actual requirements (e.g.,
simplifying the manufacturing process), which are omitted
hereinafter. In the present embodiment, in addition to being formed
on the secondary lens 422 by using manufacturing processes such as
evaporation, coating or printing processes, the patterned
reflective layer PR may be manufactured as a three-dimensional
structure in order to solve an issue that images can still not be
improved even after a surface treatment is performed on the
secondary lens 422.
[0058] Because a volume of the light source module 400 is
miniaturized, costs for mechanical members may be reduced
accordingly. Moreover, while improving the uniformity on the
illuminating surface, degrees of freedom for selecting various
parts such as the optical film 110, the diffusion plate 130 and the
light emitting element 121 may also increase accordingly, so as to
further improve the flexibility when performing related optical
designs. In addition, the light source module 400 may improve the
uniformity for illuminating and the forward luminance of the light
source module 400 by disposing the diffusion plate 130 and the
optical film 110. Therefore, the light source module 400 may
achieve similar effects and advantages of the light source module
100, which are not repeated hereinafter.
[0059] The embodiments of the invention may achieve at least one of
advantages or effects as listed below. By disposing the secondary
lens and the patterned reflective layer, the embodiments of the
invention may compensate the distribution of the light shape,
improve the uniformity for illuminating and reduce a required depth
for the optical cavity for thinning of the light source module. In
addition, because a volume of the light source module is
miniaturized, a cost for the components therein may be reduced.
Moreover, while improving the uniformity on the illuminating
surface, degrees of freedom for selecting various parts such as the
optical film, the diffusion plate, the light emitting element are
also increased accordingly, so as to further improve the
flexibility when performing related optical designs.
[0060] 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. 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 present disclosure is intended to be dedicated
to the public regardless of whether the element or component is
explicitly recited in the following claims. Furthermore, 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.
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