U.S. patent application number 13/897471 was filed with the patent office on 2013-10-03 for lens testing device.
This patent application is currently assigned to HON HAI PRECISION INDUSTRY CO., LTD.. The applicant listed for this patent is Hon Hai Precision Industry Co., Ltd. Invention is credited to I-THUN LIN.
Application Number | 20130258322 13/897471 |
Document ID | / |
Family ID | 44341523 |
Filed Date | 2013-10-03 |
United States Patent
Application |
20130258322 |
Kind Code |
A1 |
LIN; I-THUN |
October 3, 2013 |
LENS TESTING DEVICE
Abstract
A lens testing device includes a light source assembly, a
pattern plate, and an imaging sensor. The light source assembly
includes a transparent base plate, a light guide plate, and a
number of illuminants. The light source assembly uses the light
guide plate to uniformize light coming from the illuminants and
emit the light onto the pattern plate. The imaging sensor is placed
beneath the transparent base plate to sense the light passing
through the pattern plate and focused by a lens under test.
Inventors: |
LIN; I-THUN; (New Taipei,
TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hon Hai Precision Industry Co., Ltd |
New Taipei |
|
TW |
|
|
Assignee: |
HON HAI PRECISION INDUSTRY CO.,
LTD.
New Taipei
TW
|
Family ID: |
44341523 |
Appl. No.: |
13/897471 |
Filed: |
May 20, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12791879 |
Jun 2, 2010 |
8467058 |
|
|
13897471 |
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Current U.S.
Class: |
356/124.5 |
Current CPC
Class: |
G01M 11/0292 20130101;
F21V 7/28 20180201 |
Class at
Publication: |
356/124.5 |
International
Class: |
G01M 11/02 20060101
G01M011/02 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 3, 2010 |
CN |
2010103011476 |
Claims
1. A lens testing device for testing a modulation transfer function
of a lens, the lens testing device comprising: a pattern plate
defining a plurality of patterns; an imaging sensor; and a light
source assembly comprising: a transparent base plate comprising an
upper surface, the transparent base plate defining a first
receiving space above the upper surface, and a through hole
configured for accommodating the pattern plate; a light guide plate
comprising a light incident surface, a light emitting surface
perpendicular to the light incident surface, and a plurality of
microstructures formed on the light emitting surface; and at least
one illuminant; wherein the light guide plate is accommodated in
the first receiving space with the light emitting surface facing
the upper surface, the at least one illuminant is placed on the
upper surface and faces the light incident surface for emitting
light into the light guide plate, the microstructures are
configured to guide the light out of the light guide plate, and the
imaging sensor is placed at an opposite side of the base plate to
the light guide plate.
2. The lens testing device as claimed in claim 1, wherein the base
plate further comprises a lower surface, two opposite parallel
first side surfaces perpendicularly connected to the upper surface,
and two opposite parallel second side surfaces, the lower surface
is parallel to the upper surface, and the first side surfaces are
perpendicularly connected to the upper surface, the lower surface,
and the second side surfaces.
3. The lens testing device as claimed in claim 2, wherein the base
plate further comprises a pair of parallel positioning protrusions
perpendicularly extending outwards from the upper surface adjacent
to the second side surfaces, the positioning protrusions extend
along a direction perpendicular to the first side surface, and the
first receiving space is defined between the positioning
protrusions.
4. The lens testing device as claimed in claim 3, wherein two
second receiving spaces are defined at outer flanks of the
positioning protrusions, respectively, the at least one illuminant
is a plurality of illuminants, and the illuminants are accommodated
in the second receiving spaces and are equidistantly spaced from
one another in each of the second receiving spaces.
5. The lens testing device as claimed in claim 4, wherein the light
guide plate further comprises a first light reflecting surface
parallel to the light emitting surface, and another light incident
surface, the two light incident surfaces are located at opposite
ends of the light guide plate, and the illuminants are placed
corresponding to the light incident surfaces.
6. The lens testing device as claimed in claim 5, further
comprising a reflective sheet, wherein the reflective sheet
comprises a second light reflecting surface over the first
receiving space and the second receiving spaces, and the second
light reflecting surface faces the first light reflecting
surface.
7. The lens testing device as claimed in claim 1, wherein the at
least one illuminant is selected from the group consisting of a
fluorescent lamp, a cold cathode fluorescent lamp, and a light
emitting diode.
8. The lens testing device as claimed in claim 1, wherein the
microstructures are selected from the group consisting of
hemispherical bumps and hemispherical recesses.
9. The lens testing device as claimed in claim 1, wherein the
patterns include four groups of patterns respectively formed at
four corners of the pattern plate, each group of patterns comprises
two pairs of stripes perpendicular to each other, and the density
of each of the stripe pairs is different in each group.
10. A lens testing device for testing a lens, the lens testing
device comprising: a pattern plate defining a plurality of
patterns; a transparent base plate comprising a slot receiving the
pattern plate therein, the pattern plate substantially parallel to
the base plate; a light guide plate attached on the base plate, the
light guide plate having a light incident surface and a light
emitting surface substantially perpendicular to the light incident
surface, the light emitting surface facing the pattern plate; at
least one illuminant facing the light incident surface; and an
image sensor arranged at an opposite side of the base plate to the
light guide plate to capture an image of the patterns.
11. The lens testing device as claimed in claim 10, wherein the
base plate further comprises an upper surface, a lower surface, two
opposite parallel first side surfaces perpendicularly connected to
the upper surface, and two opposite parallel second side surfaces,
the lower surface is parallel to the upper surface, and the first
side surfaces are perpendicularly connected to the upper surfaces,
the lower surface, and the second side surfaces.
12. The lens testing device as claimed in claim 11, wherein the
base plate defines a first receiving space above the upper surface,
and the light guide plate is accommodated in the first receiving
space with the light emitting surface facing the upper surface.
13. The lens testing device as claimed in claim 11, wherein the
base plate further comprises a pair of parallel positioning
protrusions extending from the upper surface, the positioning
protrusions extend along a direction perpendicular to the first
side surfaces, and the first receiving space is defined between the
positioning protrusions.
14. The lens testing device as claimed in claim 13, wherein two
second receiving spaces are defined at outer flanks of the
positioning protrusions, respectively, the at least one illuminant
is a plurality of illuminants, and the illuminants are accommodated
in the second receiving spaces and are equidistantly spaced from
one another in each of the second receiving spaces.
15. The lens testing device as claimed in claim 14, wherein the
light guide plate further comprises a first light reflecting
surface parallel to the light emitting surface, and another light
incident surface, the two light incident surfaces are located at
opposite ends of the light guide plate, and the illuminants are
placed corresponding to the light incident surfaces.
16. The lens testing device as claimed in claim 14, further
comprising a reflective sheet, wherein the reflective sheet
comprises a second light reflecting surface over the first
receiving space and the second receiving spaces, and the second
light reflecting surface faces the first light reflecting
surface.
17. The lens testing device as claimed in claim 10, wherein the at
least one illuminant is selected from the group consisting of a
fluorescent lamp, a cold cathode fluorescent lamp, and a light
emitting diode.
18. The lens testing device as claimed in claim 10, wherein the
microstructures are selected from the group consisting of
hemispherical bumps and hemispherical recesses.
19. The lens testing device as claimed in claim 10, wherein the
patterns include four groups of patterns respectively formed at
four corners of the pattern plate, each group of patterns comprises
two pairs of stripes perpendicular to each other, and the density
of each of the stripe pairs is different in each group.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional application of a
commonly-assigned application entitled "LIGHT SOURCE ASSEMBLY AND
RELATED LENS TESTING DEVICE," filed on Jun. 2, 2010 with
application Ser. No. 12/791,879. The disclosure of the
above-identified application is incorporated herein by
reference.
BACKGROUND
[0002] 1. Technical Field
[0003] The present disclosure relates to a light source assembly
and a lens testing device having the light source assembly.
[0004] 2. Description of Related Art
[0005] Generally, every lens needs to pass a modulation transfer
function test to ensure the optical quality thereof. A lens testing
device for testing a modulation transfer function of a lens usually
includes a number of light tubes, a testing pattern plate, and an
image sensor. The light tubes are configured for illuminating a
testing image formed on the testing pattern plate. The testing
image of the testing pattern plate is acquired by the image sensor
through the lens to calculate a modulation transfer function of the
lens.
[0006] In a typical lens testing device, the testing pattern plate
is directly illuminated by the light tubes. However, the outer
environment easily affects the light coming out from the light
tubes. Thus, the uniformity of luminance on the testing pattern
plate is less than satisfactory.
[0007] Therefore, it is desirable to provide a lens testing device
which can overcome the above-mentioned problems.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Many aspects of the embodiments can be better understood
with references to the following drawings. The components in the
drawings are not necessarily drawn to scale, the emphasis instead
being placed upon clearly illustrating the principles of the
embodiments. Moreover, in the drawings, like reference numerals
designate corresponding parts throughout the several views.
[0009] FIG. 1 is an exploded, schematic view of a lens testing
device according to one embodiment.
[0010] FIG. 2 is an enlarged view of a portion II of FIG. 1.
[0011] FIG. 3 is a schematic view of a number of microstructures
formed on a light guide plate of FIG. 1.
[0012] FIG. 4 is an assembled view of the lens testing device of
FIG. 1.
[0013] FIG. 5 is an assembled, schematic view of the lens testing
device of FIG. 1 when the lens testing device is used to test a
lens.
DETAILED DESCRIPTION
[0014] Referring to FIGS. 1 to 5, a lens testing device 1 in
accordance with one embodiment of the present disclosure is shown.
The lens testing device 1 is configured to test a modulation
transfer function of a lens 2. The lens testing device 1 includes a
light source assembly 11, a pattern plate 18, and an imaging sensor
19. The light source assembly 11 includes a base plate 10, a light
guide plate 12, a number of illuminants 14, and a reflective sheet
16.
[0015] The pattern plate 18 is made of transparent material and
includes a number of patterns 180 formed thereon. The patterns 180
are configured to test the modulation transfer function of the lens
2. It is well known that the arrangement of the patterns 180 on the
pattern plate 18 can be different according to different kinds of
modulation transfer functions to be tested.
[0016] In this embodiment, the pattern plate 18 is substantially
rectangular and the patterns 180 are divided into four groups of
stripes correspondingly formed at four corners of the pattern plate
18. Each group of patterns 180 includes two pairs of stripes
arranged perpendicular to each other. The density of each of the
stripe pairs is different in each group.
[0017] The imaging sensor 19 includes a sensing surface 190 to
sense the light incident thereon.
[0018] The base plate 10 is substantially rectangular and includes
an upper surface 100, a lower surface 102, a pair of substantially
parallel first side surfaces 106, a pair of substantially parallel
second side surfaces 104, and a pair of substantially parallel
positioning protrusions 109. The upper surface 100 is substantially
parallel to the lower surface 102. The first side surfaces 106 are
substantially perpendicularly connected to the upper surface 100
and the lower surface 102. The second side surfaces 104 are
substantially perpendicularly connected to the upper surface 100,
the lower surface 102, and the first side surfaces 106.
[0019] The positioning protrusions 109 are substantially elongated
rectangular blocks and substantially perpendicularly extend
outwards from the upper surface 100 near the opposite second side
surfaces 104. The positioning protrusions 109 extend along a
direction substantially perpendicular to the first side surfaces
106. The positioning protrusions 109 define a first receiving space
105 therebetween. A pair of second receiving spaces 107 is defined
at outer flanks of the positioning protrusions 109, respectively.
The first receiving space 105 goes through the first side surfaces
106.
[0020] The base plate 10 defines a through hole 108 passing through
the first side surfaces 106 near the lower surface 102. The through
hole 108 extends along a direction substantially perpendicular to
the first side surfaces 106, and defines a pair of first openings
108a on the first side surfaces 106. A width of each first opening
108a is approximately equal to a distance between the positioning
protrusions 109. The base plate 10 is made of transparent material,
for example glass or plastic.
[0021] The light guide plate 12 is a substantially rectangular
plate and includes a pair of substantially parallel light incident
surfaces 124, a first light reflecting surface 120, a light
emitting surface 122, and a number of microstructures 122a. The
first light reflecting surface 120 is substantially parallel to the
light emitting surface 122. The light incident surfaces 124 are
substantially perpendicularly connected to the first light
reflecting surface 120 and the light emitting surface 122. The
microstructures 122a are formed on the light emitting surface 122
spatially corresponding to the patterns 180, and are configured to
guide the light out of the light guide plate 12 from the light
emitting surface 122. The microstructures 122a can be hemispherical
bumps or hemispherical recesses.
[0022] The illuminants 14 can be fluorescent lamps, cold cathode
fluorescent lamps, or light emitting diodes. In this embodiment,
the illuminants 14 are six light emitting diodes.
[0023] The reflective sheet 16 is substantially rectangular and
includes a second light reflecting surface 160. The second light
reflecting surface 160 is substantially similar to the upper
surface 100 in shape and size. A high reflection material is coated
on the light reflecting surface 160.
[0024] In assembly, referring to FIG. 4, the light guide plate 12
is accommodated in the first receiving space 105. The light
incident surfaces 124 correspondingly face the positioning
protrusions 109. The light emitting surface 122 is placed on the
upper surface 100. The illuminants 14 are accommodated in the
second receiving spaces 107 and spaced at equal intervals in each
of the second receiving spaces 107. In this embodiment, each second
receiving space 107 accommodates three illuminants 14.
[0025] The reflective sheet 16 is placed upon the upper surface 100
to cover the first receiving space 105 and the second receiving
space 107. The second light reflecting surface 160 faces the first
light reflecting surface 120 to further reflect the light escaping
from the first light reflecting surface 120 back into the light
guide plate 12. The reflective sheet 16 and the two positioning
protrusions 109 cooperatively define a pair of second openings 105a
on the first side surfaces 106.
[0026] The pattern plate 18 is accommodated in the through hole
108. The imaging sensor 19 is placed beneath the base plate 10 with
the sensing surface 190 facing the lower surface 102.
[0027] In use, referring to FIGS. 3 and 5, light coming from the
illuminants 14 passes through the positioning protrusions 109 and
enters the light guide plate 12 via the light incident surfaces
124. The light is totally reflected back and forth between the
first reflective surface 120 and the output surface 122 to
uniformize the luminance of the light. The light is then guided out
of the light emitting surface 122 of the light guide plate 12 by
the microstructures 122a and enters the base plate 10, passes
through the pattern plate 18 received in the through hole 108, and
finally emits from the lower surface 102 of the base plate 10. The
tested lens 2 focuses the light emitted from the base plate 10 onto
the sensing surface 190 of the imaging sensor 19. The modulation
transfer function of the lens 2 will be tested by analyzing the
light sensed by the imaging sensor 19.
[0028] The pattern plate 18 can be easily changed by sliding it out
from one of the first openings 108a. The corresponding light guide
plate 12 can also be easily changed by sliding it out from one of
the second openings 105a.
[0029] The light source assembly 11 uses the light guide plate 12
to uniformize the light from the illuminants 14 for illuminating
the patterns 180. Therefore, the uniformity of luminance on the
pattern plate 18 can be improved and the light can be used more
efficiently. Furthermore, the pattern plate 18 is well protected
because the pattern plate 18 is accommodated in the light guide
plate 12.
[0030] While various exemplary and preferred embodiments have been
described, it is to be understood that the present disclosure is
not limited thereto. To the contrary, various modifications and
similar arrangements (as would be apparent to those skilled in the
art) are intended to also be covered. Therefore, the scope of the
appended claims should be accorded the broadest interpretation so
as to encompass all such modifications and similar
arrangements.
* * * * *