U.S. patent application number 15/193563 was filed with the patent office on 2016-10-20 for imaging apparatus and medical equipment.
The applicant listed for this patent is SEIKO EPSON CORPORATION. Invention is credited to Tsukasa EGUCHI, Tetsuji FUJITA, Hideto ISHIGURO, Hidetoshi YAMAMOTO.
Application Number | 20160307058 15/193563 |
Document ID | / |
Family ID | 49385102 |
Filed Date | 2016-10-20 |
United States Patent
Application |
20160307058 |
Kind Code |
A1 |
ISHIGURO; Hideto ; et
al. |
October 20, 2016 |
IMAGING APPARATUS AND MEDICAL EQUIPMENT
Abstract
An imaging apparatus includes a light emitting section that
emits light toward a subject, and a light receiving element that
receives incident light from the subject side. The light emitting
section is configured so that the light emitted from the light
emitting section along an illumination direction that inclines with
respect to a reference direction at an angle greater than 0.degree.
and equal to or smaller than 45.degree. has a larger irradiation
strength than the light emitted from the light emitting section
along the reference direction, the reference direction being a
direction perpendicular to a plane that faces the subject.
Inventors: |
ISHIGURO; Hideto; (Shiojiri,
JP) ; EGUCHI; Tsukasa; (Matsumoto, JP) ;
FUJITA; Tetsuji; (Chino, JP) ; YAMAMOTO;
Hidetoshi; (Suwa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SEIKO EPSON CORPORATION |
Tokyo |
|
JP |
|
|
Family ID: |
49385102 |
Appl. No.: |
15/193563 |
Filed: |
June 27, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14739408 |
Jun 15, 2015 |
9405954 |
|
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15193563 |
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|
14041400 |
Sep 30, 2013 |
9064768 |
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14739408 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 5/14532 20130101;
A61B 5/1455 20130101; A61B 2010/0009 20130101; G06K 9/0004
20130101; G06K 9/00885 20130101; G06K 2009/00932 20130101; G02B
27/145 20130101; H01L 31/173 20130101; G02B 1/11 20130101; H01L
27/14629 20130101; G06K 9/2036 20130101 |
International
Class: |
G06K 9/00 20060101
G06K009/00; A61B 5/145 20060101 A61B005/145; A61B 5/1455 20060101
A61B005/1455; G06K 9/20 20060101 G06K009/20 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 1, 2012 |
JP |
2012-219278 |
Claims
1. An imaging apparatus comprising: a light emitting section that
emits light toward a subject; and a light receiving element that
receives incident light from the subject side, wherein the light
emitting section is configured so that the light emitted from the
light emitting section along an illumination direction that
inclines with respect to a reference direction at an angle greater
than 0.degree. and equal to or smaller than 45.degree. has a larger
irradiation strength than the light emitted from the light emitting
section along the reference direction, the reference direction
being a direction perpendicular to a plane that faces the
subject.
2. The imaging apparatus according to claim 1, wherein the light
emitting section is configured so that a peak wavelength of the
light emitted from the light emitting section along the reference
direction is longer than a peak wavelength of the incident light to
the light receiving element along the reference direction.
3. The imaging apparatus according to claim 1, further comprising a
transmissive section that transmits the incident light from the
subject side, wherein the light receiving element receives the
incident light transmitted through the transmissive section.
4. The imaging apparatus according to claim 1, further comprising a
lens that focuses the incident light to the light receiving
element.
5. The imaging apparatus according to claim 1, wherein the plane
that faces the subject is parallel to a surface of a substrate on
which the light emitting element is mounted.
6. A medical equipment comprising the imaging apparatus according
to claim 1, the medical equipment being configured to estimate
biometric information from an image taken by the imaging apparatus.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of U.S.
patent application Ser. No. 14/739,408 filed on Jun. 15, 2015,
which is a continuation application of U.S. patent application Ser.
No. 14/041,400 filed on Sep. 30, 2013, now U.S. Pat. No. 9,064,768.
This application claims priority to Japanese Patent Application No.
2012-219278 filed on Oct. 1, 2012. The entire disclosures of U.S.
patent application Ser. Nos. 14/739,408 and 14/041,400 and Japanese
Patent Application No. 2012-219278 are hereby incorporated herein
by reference.
BACKGROUND
[0002] 1. Technical Field
[0003] The present invention relates to an imaging apparatus which
images a subject.
[0004] 2. Background Technology
[0005] Various technologies have been proposed where an image of
veins in a living body is imaged for biometric authentication. For
example, Patent Document 1 discloses a finger authentication
apparatus where a light source section and an imaging section are
arranged so as to face each other interposing a subject (a finger
of the person to be authenticated) and light which has been emitted
from the light source section and passed through a subject is
imaged by the imaging section.
[0006] There is a problem in the technology of Patent Document 1 in
that it is difficult to reduce the size of the apparatus since it
is necessary to arrange the light source section and the imaging
section so as to face each other interposing a subject. From the
point of view of solving the problem described above, for example,
Patent Document 2 discloses an imaging apparatus with a structure
where a light source layer and a detection layer are laminated on a
surface of a substrate. Light which has been emitted from the light
source layer and passed through a subject is detected by each light
receiving element in the detection layer.
[0007] Japanese Laid-open Patent Publication No. 2003-30632 (Patent
Document 1) and Japanese Laid-open Patent Publication No. 2009-3821
(Patent Document 2) are examples of the related art.
SUMMARY
[0008] By the way, as shown in FIG. 14, when irradiation light from
a light source layer 92 is emitted in a small incident angle with
respect to the surface of a subject 90, the irradiation light from
the light source layer 92 that was reflected on the surface of the
subject 90 is reflected on the surface of the subject 90 and
directly reaches to a light receiving element 94 (that is, the
reflection of the light source layer 92 is imaged in a
photographing image) so that it becomes in the state that a
specific area on the surface of the subject 90 has extreme high
brightness (hereinafter referred to as "glare"). Therefore, it is
difficult to take a fine and clear image of veins, which are, for
example, the inside of the subject 90. On the other hand, as shown
in FIG. 15, when the irradiation light from the light source layer
92 is securely emitted in an appropriate incident angle with
respect to the surface of the subject 90, the reflected light on
the surface of the subject 90 does not directly reach to the light
receiving element 94 (only scattering light on the surface of the
subject 90 reaches to the light receiving element 94) so that the
generation of the above described glare can be suppressed. However,
when the subject 90 is illuminated in one direction inclined with
respect to the surface of the subject 90, the shadows that the
surface structure of the subject 90 (e.g., fingerprints or
wrinkles) was reflected is emphasized. Thus, it is difficult to
take a fine and clear image of veins that are the inside of the
subject 90. Considering the situation described above, the
advantage of the invention is to take an image of a subject by
suppressing glares or shadows.
[0009] In order to solve the problem described above, an imaging
apparatus of the invention is provided with a light receiving
section in which a plurality of light receiving elements is
arranged, and a light source section arranged in a subject side of
the light receiving section and including a light emitting section
that emits light toward the subject and a plurality of transmissive
sections where the incident light from the subject side is
transmitted to each light receiving element side. The light
emitting section includes a first translucent layer having light
permeability, which includes a light emitting layer, a
semi-transmissive reflection layer located in the subject side of
the first translucent layer, and a reflection layer, which is
opposed to the semi-transmissive reflection layer interposing the
first translucent layer. A resonation structure is formed so that
the light emitted from the light emitting layer is resonated
between the semi-transmissive reflection layer and the reflection
layer. The plurality of the transmissive sections respectively
includes a second translucent layer having light permeability, and
a first semi-transmissive reflection layer and a second
semi-transmissive reflection layer that are opposed each other
interposing the second translucent layer. A resonation structure is
formed so that the irradiation light from the light emitting layer
is resonated between the first semi-transmissive reflection layer
and the second semi-transmissive reflection layer. A first resonant
length (e.g., resonant length L1) between the reflection layer and
the semi-transmissive reflection layer in the light emitting
section is more than a second resonance length (e.g., resonant
length L2) between the first semi-transmissive reflection layer and
the second semi-transmissive reflection layer in the transmissive
section. In the above structure, the first resonant length of the
resonant structure of the light emitting section is more than the
second resonant length of the resonant structure of the
transmissive section so as to approach between a peak wavelength
(e.g., peak wavelength .lamda.1) of the irradiation intensity from
the light emitting section in a direction inclined with respect to
a reference direction, which is perpendicular to the reflection
surface of the resonant structure, and a peak wavelength (e.g.,
peak wavelength .lamda.2) of the irradiation intensity from the
transmissive section with respect to the reference direction in
comparison with the case that the first resonant length and the
second resonant length are matched each other. That is, an imaging
light in a specific wavelength is emitted from the light emitting
section in a direction inclined with respect to the reference
direction and passes through the transmissive section in a
direction parallel to the reference direction so that it progresses
to the light receiving section side. Therefore, it is possible to
take a fine and clear image of the subject by suppressing glares or
shadows on the surface of the subject.
[0010] In a preferred aspect of the invention, an imaging apparatus
includes a light emitting section that emits light toward a
subject, and a light receiving element that receives incident light
from the subject side. The light emitting section is configured so
that the light emitted from the light emitting section along an
illumination direction that inclines with respect to a reference
direction at an angle greater than 0.degree. and equal to or
smaller than 45.degree. has a larger irradiation strength than the
light emitted from the light emitting section along the reference
direction, the reference direction being a direction perpendicular
to a plane that faces the subject.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Referring now to the attached drawings which form a part of
this original disclosure:
[0012] FIG. 1 is a cross-sectional diagram of an imaging apparatus
according to an embodiment of the invention;
[0013] FIG. 2 is an exploded cross-sectional diagram of the imaging
apparatus;
[0014] FIG. 3 is a planar diagram illustrating a relationship
between each element of the imaging apparatus;
[0015] FIG. 4 is a cross-sectional diagram where the imaging
apparatus is partially enlarged;
[0016] FIG. 5 is a cross-sectional diagram of a light emitting
section in a light source section of the imaging apparatus;
[0017] FIG. 6 is a cross-sectional diagram of a transmissive
section in the light source section of the imaging apparatus;
[0018] FIG. 7 is an explanatory diagram of an irradiation angle of
imaging light;
[0019] FIG. 8 is a graph showing a relationship between irradiation
intensity and a wavelength from the light emitting section in every
irradiation angle;
[0020] FIG. 9 is a graph showing a relationship between irradiation
intensity and a wavelength from the transmissive section in every
irradiation angle;
[0021] FIG. 10 is a schematic diagram where the imaging light is
emitted from the light emitting section;
[0022] FIG. 11 is a cross-sectional diagram showing a specific
configuration of the light emitting section;
[0023] FIG. 12 is a cross-sectional diagram showing a specific
configuration of the transmissive section;
[0024] FIG. 13 is a graph showing a relationship between an
incident angle with respect to a substrate and transmittance and
reflectance;
[0025] FIG. 14 is an explanatory diagram of a shadow that becomes
apparent when a subject is illuminated in a small incident angle;
and
[0026] FIG. 15 is an explanatory diagram of a shadow that becomes
apparent when a subject is illuminated in a large incident
angle.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
Embodiment
[0027] FIG. 1 is a cross-sectional diagram of an imaging apparatus
100 according to one embodiment of the invention. FIG. 2 is an
exploded cross-sectional diagram of the imaging apparatus 100. The
imaging apparatus 100 of the present embodiment is a sensing
apparatus which images a subject 200 in a state in which
illumination light with a specific wavelength (referred to below as
"imaging light") is irradiated, and for example, is preferably used
as a biometric authentication apparatus (vein sensor) which images
an image of veins in a living body (typically, a human finger). The
imaging light is a predetermined frequency of an optic element
where the intensity becomes a peak near a specific wavelength
.lamda. (hereinafter referred to as "imaging wavelength"). It gives
an example that the imaging wavelength .lamda. is 850 nm of
near-infrared light below, but the imaging wavelength can be
appropriately changed in response to the optical properties
(transmittance or reflectance), and the like.
[0028] As shown in FIG. 1 and FIG. 2, the imaging apparatus 100 of
the invention is provided with a light receiving section 10, light
focusing section 20, and a light emitting section 30. The light
emitting section 30 is arranged in a subject 200 side of the light
receiving section 10 (between the light receiving section 10 and
the subject 200), and the light focusing section 20 is arranged in
the subject 200 side of the light emitting section 30 (between the
light emitting section 30 and the subject 200). That is, the light
emitting section 30 is located between the light receiving section
10 and the light focusing section 20. Schematically, the incident
light from the subject 200 that was illuminated by imaging light
emitted from the light emitting section 30 is focused in the light
focusing section 20 and passes through the light emitting section
30 and reaches to the light receiving section 10.
[0029] The light receiving section 10 is an element that images the
subject 200 and is configured to include a substrate 12 and a
plurality of light receiving elements 14. The substrate 12 is a
member with a plate shape which is formed from, for example, a
semiconductor material. The plurality of light receiving elements
14 are formed on a surface (acceptance surface) 121 on the subject
200 side of the substrate 12, and are ordered in a matrix formation
in a planar view (that is, when viewed from a direction which is
perpendicular to the surface 121) as shown in FIG. 3. Each of the
plurality of light receiving elements 14 generates a detection
signal according to the amount of imaging light. An image of the
subject 200 is generated by an image processing of the detection
signal that was generated in each of the plurality of light
receiving elements 14. For example, a Complementary Metal Oxide
Semiconductor (CMOS) sensor or a Charge Coupled Device (CCD) sensor
which is well known is preferably used as the light receiving
section 10.
[0030] The light focusing section 20 in FIG. 1 is an element which
focuses imaging light that arrives from the subject 200, and is
configured to include a substrate 22 and a plurality of lenses
(microlenses) 24. As shown in FIG. 2, the substrate 22 is an
optically transmissive (a property whereby it is possible for
imaging light to pass through) member with a plate shape which
includes a surface 221 which opposes the subject 200 and a surface
222 on the opposite side to the surface 221. For example, a glass
substrate or a quartz substrate is preferably adopted as the
substrate 22. The plurality of lenses 24 are formed on the surface
222 of the substrate 22. Each of the lenses 24 is a convex lens
which focuses imaging light which is incident from the subject 200
onto the surface 221 of the substrate 22 and passes through the
substrate 22.
[0031] FIG. 4 is a cross-sectional diagram of a part corresponding
to one light receiving element 14 in the imaging elements. As shown
in FIG. 1 and FIG. 4, each lens 24 of the light focusing section 20
and each light receiving element 14 of the light receiving section
10 are one to one correspondence. Specifically, as shown in FIG. 4,
a light axis L0 of each lens 24 passes through the light receiving
element 14 (typically, a center of a light sensing area of the
light receiving element 14) corresponding to the lens 24.
Therefore, the plurality of lenses 24 is arranged in matrix
formation in a planer view in a similar manner as each light
receiving element 14 as shown in FIG. 3. For example, an arbitrary
manufacturing technique of such as a method (reflow method) where
each of the lenses 24 is formed by heat deforming numerous fine
resists which are formed on the substrate 22, a method where each
of the lenses 24 is formed by a photolithography process which uses
an area gradation mask, a method where the substrate 22 and each of
the lenses 24 are integrally formed by polishing and molding a
member with a plate shape, or the like is adopted in the
manufacturing of each of the lenses 24.
[0032] The light emitting section 30 in FIG. 1 has an element that
imaging light is generated and the subject 200 is illuminated and
the imaging light, which was focused in each lens 24, passes to
each light receiving element 14 side, and is configured to include
a substrate 32, a light blocking layer 33, a wiring layer 35, a
light source section 36, and a protection layer 37. As shown in
FIG. 2, the substrate 32 is an optically transmissive member with a
plate shape (for example, a glass substrate or a quartz substrate)
which includes a surface 321 which opposes the light focusing
section 20 (each of the lenses 24) and a surface 322 on the
opposite side to the surface 321. The light blocking layer 33 is a
film body having a light blocking effect (a property to absorb or
reflect imaging light) and is formed on the surface 322 of the
substrate 32. For example, the light blocking layer 33 is formed by
a resin material in which a black agent (black pigment) such as,
for example, carbon black, and the like is dispersed, or a metal
material such as chrome, and the like having the light blocking
effect. As shown in FIG. 2 and FIG. 4, a plurality of
circular-shaped opening sections 34 is formed on the light blocking
layer 33. Each of the opening sections 34 of the light blocking
layer 33 and each of lenses 24 of the light focusing section 20 (or
each of the light receiving elements 14 of the light receiving
section 10) are one to one correspondence. Specifically, as shown
in FIG. 4, the light axis L0 in each of the lenses 24 passes
through the opening section 34, which corresponds to the lens 24
(typically, it passes through a center of the opening section 34).
Therefore, as shown in FIG. 3, each of the opening sections 34 is
arranged in a matrix formation in a planar view in a similar manner
as each of the lenses 24 or each of the light receiving elements
14.
[0033] The wiring layer 35 is formed on the surface 321 of the
substrate 32, and is configured to include a wire for supplying
electric current to the light source section 36. The light source
section 36 is formed on the surface of the wiring layer 35, and
illuminates the subject 200. The imaging light from the subject 200
side passes to each light receiving element 14 side. As shown in
FIG. 2 and FIG. 4, the light source section 36 is separated into a
light emitting section 50 and a plurality of transmissive sections
60 in a planer view (that is, it is in a state of viewing in a
direction perpendicular to the surface 321 of the substrate 32).
The light emitting section 50 generates and emits imaging light to
illuminate the subject 200. The plurality of transmissive sections
60 respectively transmits the incident light from the subject 200
side to each of the light receiving elements 14 side. As shown in
FIG. 3, each of the transmissive sections 60 is formed in a
circular shape in a planer view. Each of the transmissive sections
60 of the light source section 36 and each of the lenses 24 of the
light focusing section 20 (or each of the light receiving elements
14 of the light receiving section 10) are one to one
correspondence. Specifically, as shown in FIG. 4, the light axis L0
of each of the lenses 24 passes through the transmissive sections
60 (typically, it passes through a center of the transmissive
section 60) corresponding to the lens 24. Therefore, as shown in
FIG. 3, each of the transmissive sections 60 is arranged in a
matrix formation in a planer view in a similar manner as each of
the lenses 24 or the light receiving elements 14. Each of wirings
in the wiring layer 35 is formed in a region overlapping with the
light emitting section 50 in a planer view, and it does not overlap
with each of the transmissive sections 60. The protection layer 37
in FIG. 1 has an element (sealing layer) to protect from external
air or fluid by sealing the light source section 36, and it is
formed by an insulating material having light permeability (e.g.,
resin material).
[0034] The light receiving section 10 and the light emitting
section 30 are mutually fixed with a space by, for example, an
adhesive agent 18 having light permeability. Also, the respective
peripheries of the light focusing section 20 and the light emitting
section 30 are mutually fixed. In FIG. 1 and FIG. 4, a
configuration that the light focusing section 20 and the light
emitting section 30 are connected to contact the surface of each of
the lenses 24 of the light focusing section 20 and the surface of
the protection section 30 of the light emitting section 30 is
exemplified. However, it is possible to mutually fix the light
focusing section 20 and the light emitting section 30 so as to
oppose each other with a space mutually between the surface of each
of the lenses 24 and the surface of the protection layer 37. Also,
it is possible to mutually fix the light focusing section 20 and
the light emitting section 30 by using an adhesive agent having
light permeability that has a small refraction index in comparison
with the material of each of the lenses 24.
[0035] In the configuration described above, the imaging light
which is output from the light emitting section 50 in the light
source section 36 passes through the light focusing section 20 (the
substrate 22 and each of the lenses 24) and irradiates the subject
200, passes through or is reflected by veins inside the subject 200
and is incident on the light focusing section 20, and passes
through the transmissive sections 60 of the light source section 36
and the opening sections 34 in the substrate 32 and the light
blocking layer 33 after having been focused by each of the lenses
24 and reaches the light receiving element 14. Accordingly, an
image of veins in the subject 200 is imaged.
[0036] In the configuration as described above, since the light
source section 36 is arranged between each of the light receiving
elements 14 in the light receiving section 10 and the subject 200,
it is easy to reduce the size of the apparatus in comparison to the
technique in Patent Document 1 where a light source section and an
imaging section are arranged so as to oppose each other interposing
the subject. In addition, since the light emitting section 50 which
irradiates imaging light onto the subject 200 is distributed in a
planar form, it is possible to reduce uneven distribution of the
amount of irradiating light with regard to the subject 200 (to
uniformly illuminate the subject 200) in comparison to a case where
a point light source such as a Light Emitting Diode (LED), and the
like being used to illuminate the subject 200. Moreover, in the
present embodiment, since the imaging light from the subject 200
which is illuminated by the light source section 36 reaches the
light receiving element 14 after having been focused by each of the
lenses 24 in the light focusing section 20, there is an advantage
in that it is possible to secure a sufficient amount of light which
reaches from the subject 200 to each of the light receiving
elements 14 in comparison to the technique in Patent Document 2
where there is no element which focuses the imaging light.
[0037] FIG. 5 is a cross-sectional diagram that a light emitting
section 50 in a light source section 36 is enlarged. As shown in
FIG. 5, the light emitting section 50 is configured to include a
reflection layer 52, a first translucent layer 54, and a
semi-transmissive reflection layer 56. The reflection layer 52 is
formed on the surface (on the light receiving section 10 side
viewed from the first translucent layer 54) of the wiring layer 35,
and the first translucent layer 54 is formed on the surface of the
reflection layer 52, and the semi-transmissive reflection layer 56
is formed on the surface (on the subject 200 side viewed from the
first translucent layer 54) of the first translucent layer 54. That
is, the reflection layer 52 and the semi-transmissive reflection
layer 56 are opposed each other interposing the first translucent
layer 54.
[0038] The first translucent layer 54 is a thin film having light
permeability that includes the light emitting layer which generates
imaging light. The reflection layer 52 is a thin film having light
reflectivity so as to reflect the imaging light, which is emitted
from the light emitting layer and progresses to the light receiving
section 10, to the subject 200 side. The semi-transmissive
reflection layer 56 is a thin film (half mirror) having
semi-transmissive reflectivity so as to transmit a part of the
imaging light, which arrives from the first translucent layer 54,
(imaging light that the light emitting layer generates and
progresses to the subject 200 side, or imaging light reflected in
the reflection layer 52) and to reflect the remaining.
[0039] As described above, the reflection layer 52 and the
semi-transmissive reflection layer 56 are opposed each other
interposing the first translucent layer 54 so that the resonation
structure (microcavity) that resonates the imaging light, which is
emitted from the light emitting layer of the first translucent
layer 54, between the reflection layer 52 and the semi-transmissive
reflection layer 56. That is, the light emitted from the light
emitting layer is reciprocated between the reflection layer 52 and
the semi-transmissive reflection layer 56, and passes through the
semi-transmissive reflection layer 56 and is emitted to the subject
200 after a resonance component of a wavelength in response to an
optical distance L1 (hereinafter referred to as "resonance length")
between the reflection layer 52 and the semi-transmissive
reflection layer 56 was alternatively amplified. That is, the light
emitting section 50 functions as a bandpass filter that
alternatively emphasizes a wavelength component in response to the
resonance length L1 in the imaging light that the light emitting
layer generates. The resonance length L1 corresponds to a film
thickness of the first translucent layer 54.
[0040] FIG. 6 is a cross-sectional diagram that the transmissive
section 60 in the light source section 36 is enlarged. As shown in
FIG. 6, the transmissive section 60 is configured to include a
first semi-transmissive reflection layer 62, a second translucent
layer 64, and a second semi-transmissive reflection layer 66. The
first semi-transmissive reflection layer 62 is formed on the
surface (on the light receiving section 10 side viewed from the
second translucent layer 64) of the wiring layer 35, and the second
translucent layer 64 is formed on the surface of the first
semi-transmissive reflection layer 62, and the second
semi-transmissive reflection layer is formed on the surface (on the
subject 200 side viewed from the second translucent layer 64) of
the second translucent layer 64. That is, the first
semi-transmissive reflection layer 62 and the second
semi-transmissive reflection layer 66 are opposed each other
interposing the second translucent layer 64.
[0041] The second translucent layer 64 is a thin film having light
permeability. The first semi-transmissive reflection layer 62 is a
thin film (half mirror) having semi-transmissive reflectivity so as
to pass through a part of the imaging light, which progresses the
inside of the second translucent layer 64 to the light receiving
section 10 side, to the light receiving section side 10 and reflect
the remaining to the subject 200 side (the second semi-transmissive
reflection layer 66 side). The second semi-transmissive reflection
layer 66 is a thin film (half mirror) having semi-transmissive
reflectivity so as to transmit a part of the imaging light, which
was focused in each of the lenses 24 of the light focusing section
20 and from the subject 200 side, and take it inside of the second
translucent layer 64, and reflect a part of the imaging light,
which is reflected in the first semi-transmissive reflection layer
62 and progresses to the subject 200 side, to the subject 200
side.
[0042] As described above, the first semi-transmissive reflection
layer 62 and the second semi-transmissive reflection layer 66 are
opposed each other interposing the second translucent layer 64 so
as to form a resonant structure that resonates imaging light, which
was focused in each of lenses 24 of the light focusing section 20
and from the subject 200, between the first semi-transmissive
reflection layer 62 and the second semi-transmissive reflection
layer 66. That is, the imaging light, which arrives from the
subject 200 side and transmits through the second semi-transmissive
reflection layer 66, is reciprocated between the first
semi-transmissive reflection layer 62 and the second
semi-transmissive reflection layer 66, and a resonance component of
a wavelength in response to a resonance length (optical distance)
L2 between the first semi-transmissive reflection layer 62 and the
second semi-transmissive reflection layer 66 is alternatively
amplified and passes through the first semi-transmissive reflection
layer 62 and emits to the light receiving section 10 side. That is,
the transmissive section 60 functions as a bandpass filter that
alternatively emphasizes a wavelength component in response to the
resonance length L2. The resonance length L2 corresponds to the
film thickness of the second translucent layer 64.
[0043] By the way, a relationship between the wavelength and the
strength of the irradiation light from the resonance structure (a
wavelength that the strength is amplified in the resonance
structure) depends on an irradiation angle .theta. of irradiation
light. As shown in FIG. 7, the irradiation angle .theta. means an
angle with respect to a reference direction D0 perpendicular to the
reflection surface of the resonance structure. The reference
direction D0 is a direction (a direction parallel to a light axis
L0 of each of lenses 24 of the light focusing section 20)
perpendicular to the surface 121 of the substrate 12.
[0044] FIG. 8 is a graph showing a relationship between a
wavelength and strength of the irradiation light from the resonance
structure of the light emitting section 50 in the light source
section 36 in a plurality of irradiation angles .theta. (.theta.=0,
15, 30, 45, 60 [.degree.]). In FIG. 8, the spectral characteristics
of internal luminescence of the light emitting layer are described
in a broken line. As is understood from FIG. 8, as the irradiation
angle .theta. of the irradiation light from the resonance structure
increases, the wavelengths in which the irradiation strength
becomes a peak (hereinafter referred to as "peak wavelength") tends
to be reduced. Also, as the resonance length L1 of the resonance
structure of the light emitting section 50 reduces, a peak
wavelength of the emitted light tends to be shifted to a short
wavelength side.
[0045] As described above in reference to FIG. 14, when the light
is illuminated to the surface of the subject 200 in a small
incident angle (an angle close to the front direction), the glare
that a specific region of the surface of the subject 200 becomes
extremely high brightness becomes significant. Therefore, in view
of preventing it from the glare, it is preferred that a peak
wavelength .lamda.1 of the irradiation strength for the
illumination direction that inclines in a specific angle .theta.x
(hereinafter referred to as "target angle") with respect to the
reference direction D0 (.theta.=0.degree.) matches with an imaging
wavelength .lamda..
[0046] In consideration of the above tendency, in the present
embodiment, as shown in FIG. 8, the resonance length L1 of the
resonance structure of the light emitting section 50 is selected so
that a peak wavelength .lamda.1 of the irradiation strength from
the light emitting section 50 in the illumination direction of the
target angle .theta.x matches with (or comes close to) a desired
imaging wavelength .lamda. (850 nm). That is, the imaging light of
the imaging wavelength .lamda. in the light emitted from the light
emitting layer is emitted in the illumination direction that
inclines in the target angle .theta.x with respect to the reference
direction D0. In FIG. 8, a case that the target angle .theta.x was
set to 45.degree. is exemplified.
[0047] In a configuration that the resonance length L1 was selected
in the above condition, as shown in FIG. 9, the imaging light of
the imaging wavelength .lamda. (peak wavelength .lamda.1) is
irradiated in a direction of the target angle .theta.x
(.theta.x=45.degree.) with respect to the reference direction D0 in
whole periphery of a normal line (line parallel to the reference
direction D0) as an axis in any point P of the light emitting
section 50. That is, the imaging light of the imaging wavelength
.lamda. arrives to any point of the surface of the subject 200 from
various directions that are inclined in the target angle .theta.x
with respect to the reference direction D0. Therefore, it is
possible to suppress shadows, which reflect the surface structure
(texture) of the subject 200, in comparison with the case that the
subject 200 is illuminated from one direction that was inclined
with respect to the normal line of the surface of the subject 200
as shown in FIG. 15.
[0048] FIG. 10 is a graph showing a relationship between a
wavelength and strength of light emitted from the resonance
structure of the transmissive section 60 in the light source
section 36 in a plurality of irradiation angles .theta. (.theta.=0,
15, 30, 45, 60 [.degree.]). The vertical axis of FIG. 10 can be
seen as same as the transmittance of the transmissive section 60.
FIG. 10 shows a characteristic in the case that the resonance
length L2 of the resonance structure of the transmissive section 60
is less than the resonance length L1 of the resonance structure of
the light emitting section 50 in a solid line. A characteristic for
the irradiation angle .theta., which is 0.degree., based on a
configuration (hereinafter referred to as "comparison example")
presuming that the resonance length L1 and the resonance length L2
are matched each other is shown in a broken line. As is understood
from FIG. 10 in the similar manner as FIG. 8, as the irradiation
angle .theta. of the irradiation light from the resonance structure
increases, it tends to reduce the peak wavelength of the
irradiation light. Also, as is understood from the comparison
example of FIG. 10, as the resonance length L2 of the resonance
structure of the transmissive section 60 reduces in comparison to
the comparison example (resonance length L1), the peak wavelengths
of the light emitted from the resonance structure tend to be
shifted to the short wavelength side in comparison to the
comparison example as shown in FIG. 10.
[0049] From the point of view that the imaging light incident to
the transmissive section 60 from the subject 100 side is
effectively transmitted to the light receiving section 10
(maintaining the use efficiency of imaging light at high level), it
is preferred that the peak wavelength .lamda.2 of the irradiation
strength (transmittance of the transmissive section 60) from the
transmissive section 60 with respect to the reference direction D0
(direction of light axis L0 of lenses 24) matches with the imaging
wavelength .lamda.. In consideration of the above tendency, in the
present embodiment, as shown in FIG. 10, the resonance length L2 of
the resonance structure of the transmissive section 60 is selected
so that the peak wavelength .lamda.2 of the irradiation strength
from the transmissive section 60 with respect to the reference
direction D0 (.theta.=0.degree.) matches with (come close to) the
desired imaging wavelength .lamda. (850 nm). That is, the imaging
light of the imaging wavelength .lamda. incident to the
transmissive section 60 from the subject 200 side is emitted
parallel to the reference direction (.theta.=0.degree.) from the
transmissive section 60.
[0050] As shown in FIG. 10 in a broken line, in the comparison
example that the resonance length L2 is unified with the resonance
length L1, the peak wavelength A2 of the emitting strength with
respect to the reference direction D0 becomes a value approximately
900 nm. As described above, as the resonance length L2 is reduced
in comparison with the comparison example (resonance length L1),
the peak wavelength .lamda.2 of the light emitted from the
resonance structure is shifted to the short wavelength side.
Therefore, in the present embodiment, the resonance length L2 is
selected to be less than the resonance length L1 (L2<L1).
Specifically, the resonance length L1 and the resonance length L2
are selected to be that the resonance length L1 is 10% (preferably
8%) more than the resonance length L2. The resonance length L2 is
selected to become approximately one half of the imaging wavelength
.lamda. (0.5 wavelength).
[0051] In a configuration that the resonance length L2 is less than
the resonance length L1 as described above, the peak wavelength
.lamda.1 of the irradiation strength from the light emitting
section 50 for the target angle .theta.x (.theta.x=45.degree.)
inclined with respect to the reference direction D0 and the peak
wavelength 12 of the irradiation strength from the transmissive
section 60 with respect to the reference direction D0
(.theta.=0.degree.) come close to each other in comparison to the
comparison example that the resonance length L1 and the resonance
length are unified. That is, it is to say that in the present
embodiment, it is possible that the resonance length L1 and the
resonance length L2 are selected as to approach between the peak
wavelength .lamda.1 and the peak wavelength .lamda.2 in comparison
with the comparison example (ideally, both the peak wavelength
.lamda.1 and the peak wavelength .lamda.2 are matched).
[0052] As described above, the imaging light of the desired imaging
wavelength .lamda. is emitted from the light emitting section 50 in
an illumination direction that inclines the target angle .theta.x
with respect to the reference direction D0, and it passes through
the transmissive section 60 in the reference direction D0 and
progresses to the light receiving section 10 side. Therefore, in
the present embodiment, it is possible to take a fine and clear
image of the subject 200 while the glares or the shadows of the
surface of the subject 200 are suppressed.
<Specific Configurations of Light Emitting Section 50 and
Transmissive Section 60>
[0053] The specific configurations of the light emitting section 50
and the transmissive section 60 described above are exemplified
below. FIG. 11 is a cross-sectional diagram showing a specific
configuration of the light emitting section in the light source
section 36. FIG. 12 is a cross-sectional diagram showing a specific
configuration of the transmissive section 60 in the light source
section 36. By the way, in the description below, in a case that a
plurality of elements is formed by a common layer (single layer or
multiple layers) in the same process, it is written as the phrase
"the same layer is formed" or the phrase "the same layers are
formed". Each element formed by the same layer is made by a common
material, and the respective film thicknesses are roughly
corresponded each other.
[0054] The reflection layer 52 of the light emitting section 50 is
configured to include a basic reflection layer 71 and a dielectric
multilayer film 72 as shown in FIG. 11, and the first
semi-transmissive reflection layer 62 of the transmissive section
60 is configured to include the dielectric multilayer film 72 as
shown in FIG. 12. The dielectric multilayer film 72 of the light
emitting section 50 and the dielectric multilayer film 72 of the
transmissive section 60 are formed in the same layer, and the first
semi-transmissive reflection layer 62 does not include the basic
reflection layer 71. That is, the first semi-transmissive
reflection layer 62 of the transmissive section 60 has a
relationship that the layers from the reflection layer 52 of the
light emitting section 50 to the basic reflection layer 71 are
omitted.
[0055] The basic reflection layer 71 in FIG. 11 is a thin film
having light permeability, and is formed on the surface (on the
surface 321 of the substrate 32) of the wiring layer 35 by a metal
material which is, for example, silver, aluminum, or the like.
Specifically, the basic reflection layer 71 is formed by
alternatively removing the circular area corresponding to each of
the transmissive sections 60 in the thin film having light
permeability that was formed in the entire area of the substrate
32.
[0056] The dielectric multilayer film 72 in both of the light
emitting section 50 and the transmissive section 60 is a dielectric
mirror in which a plurality of high refractive index layers 721 and
a plurality of low refractive index layers 722 are alternatively
laminated. The high refractive index layer 721 and the low
refractive index layer 722 are a thin film (dielectric layer)
having light permeability, and the refraction index of the high
refractive index layer 721 is more than the low refractive index
layer 722. Each of the high refractive index layers is formed by,
for example, amorphous silicon (a-Si), and each of the low
refractive index layers is formed by, for example, silicone nitride
(SiNx) or silicon oxide (SiOx). The film thickness of each of the
high refractive index layers and each of the low refractive index
layers is set to be that the respective optical distances (length
of light path) becomes one-quarter of the imaging length
.lamda..
[0057] According to the configuration that the reflection layer 52
of the light emitting section 50 was formed by laminating the basic
reflection layer 71 and the dielectric multilayer film 72 as
exemplified above, it is possible to improve the reflectance
(approximately 95%) in comparison with the case that the reflection
layer 52 is formed by a single basic reflection layer 71. Also,
there is an advantage that the optical loss can be reduced enough
by using the dielectric multilayer film 72. By the way, there is a
characteristic to absorb visible light in amorphous silicon which
is the material of the high refractive index layer 721 so that
according to the configuration that the dielectric multilayer film
72 includes the high refractive index layer 721 of amorphous, there
is an advantage that it is not necessary to provide an optical
filter independently to block the visible light.
[0058] The first translucent layer 54 of the light emitting section
50 is configured to include a protection layer 73, a transparent
electrode layer 74, and a light emitting layer 75 as shown in FIG.
11, and the second translucent layer 64 of the transmissive section
60 is configured to include the protection layer 73 and the light
emitting layer 75 as shown in FIG. 12. The protection layer 73 of
the first translucent layer 54 and the protection layer 73 of the
second translucent layer 64 are formed in the same layer, and the
light emitting layer 75 of the first translucent layer 54 and the
light emitting layer 75 of the second translucent layer 64 are
formed in the same layer. The second translucent layer 64 does not
include the transparent electrode layer 74. That is, the second
translucent layer 64 of the transmissive section 60 has a
relationship that the layers from the first translucent layer 64 to
the transparent electrode layer 74 are omitted.
[0059] The protection layer 73 in both of the light emitting
section 50 and the transmissive section 60 is a thin film having
light permeability, and for example, silicone nitride (SiNx) or
silicon oxide (SiOx) are formed on the surface of the dielectric
multilayer film 72 in the similar manner as the low refractive
layer 722 of the dielectric multilayer film 72. The transparent
electrode layer 74 is a conducting layer having light permeability
that functions as an electrode (anelectrode) to supply electric
current to the light emitting layer 75 in the light emitting
section 50. For example, it is made by an electrical conducting
material having light permeability such as, for example, Indium Tin
Oxide (ITO), or the like, and it is formed to have 20 nm of film
thickness, for example, and covers the protection layer 73.
Specifically, the transparent electrode layer 74 is formed by
alternatively removing the circular area corresponding to each of
the transmissive sections 60 in the conducting film having light
permeability that was formed in the entire of the surface of the
protection layer 73. The transparent electrode layer 74 is
electrically connected to the wiring (not shown) of the wiring
layer 35 through a conduction hole (not shown) that penetrates
through the protection layer 73.
[0060] The light emitting layer 75 in both of the light emitting
section 50 and the light transmissive section 60 are an
electrooptic layer that generates imaging light by supplying the
electric current, and is formed by, for example, an
Electroluminescence material (organic EL). By the way, the light
emitting layer 75 is illustrated as a single layer in FIG. 11 and
FIG. 12 for descriptive purposes, but it is possible to form a
charge injection layer (hole injection layer, electron injection
layer) or a charge transport layer (hole transport layer, electron
transport layer) to improve luminance efficiency of the light
emitting layer 75.
[0061] As shown in FIG. 11 and FIG. 12, the semi-transmissive
reflection layer 56 of the light emitting section 50 and the second
semi-transmissive reflection layer 66 of the transmissive section
60 are formed in the same layer (reflection conductive layer 76).
The reflection conductive layer 76 of the light emitting section 50
functions as electrode (negative electrode) to supply electric
current to the light emitting layer 75. That is, in the light
emitting section 50, the transparent electrode layer 74 and the
reflection conductive layer 76 are opposed each other interposing
the light emitting layer 75 so as to form a light emitting element
(top mission type organic EL element). The light emitting layer 75
is existed in the transmissive section 60, but the transparent
electrode layer 74 is omitted in the transmissive section 60 so
that the light emitting element is not formed.
[0062] By forming the thin film having the light reflectivity as
thin as possible, the semi-transmissive reflectivity of the
reflection conductive layer 76 is realized. For example, the
reflection conductive layer 76 is formed by an alloy (MgAg) that
mixes magnesium (Mg) and silver (Ag). Specifically, from the
viewpoint to realize good semi-transmissive reflectivity, the alloy
in which the ratio of silver (% by weight) is more than the ratio
of magnesium is preferred as a material of the conducting layer.
For example, the reflection conductive layer 76 is formed in the
film thickness from approximately 20 nm to 30 nm with an alloy in
which the ratio of the magnesium is less than 10% and the ratio of
silver is more than 90%. By the way, it is possible to realize the
semi-transmissive reflectivity by forming numerous fine apertures
in the reflection conductive layer 76. The protection layer 37 is
formed on the surface of the reflection conductive layer 76 in both
of the light emitting section 50 and the transmissive section
60.
[0063] In the configuration described above, as is understood from
FIG. 11, the resonance length L1 of the resonance structure of the
light emitting section 50 corresponds to the distance between the
front surface of the dielectric multilayer film 72 (most top layer
of the high refractive index layer 721) of the reflection layer 52
and the back surface of the semi-transmissive reflection layer
(reflection conductive layer 76). That is, the resonance length L1
of the light emitting section 50 is total value of the film
thicknesses of the protection layer 73, the transparent electrode
layer 74, and the light emitting layer 75. On the other hand, as is
understood from FIG. 12, the resonance length L2 of the resonance
structure of the transmissive section 60 corresponds to the
distance between the front surface of the dielectric multilayer
film 72 of the first semi-transmissive reflection layer 62 and the
back surface of the second semi-transmissive reflection layer 66.
That is, the resonance length L2 of the transmissive section 60 is
a total value of the film thicknesses of the protection layer 73
and the light emitting layer 75. As is understood from the
description above, the resonance length L2 is less than the
resonance length L1 by the film thickness of the transparent
electrode layer 74. By the configuration that the resonance length
L1 of the light emitting section 50 and the resonance length L2 of
the transmissive section 60 are differentiated in response to
existence or non-existence of a part of layers of configuration
(transparent electrode layer 74 in the above example) in the
respective resonance structures of the light emitting section 50
and the transmissive section 60 as described above, it is possible
to differentiate the resonance length L1 and the resonance length
L2 with a simple process in comparison with a configuration that
the film thickness of the configured layer itself of the resonance
structure in the light emitting section 50 and the transmissive
section 60 is differentiated.
Modified Example
[0064] It is possible for each of the embodiment described above to
be changed in various ways. Various aspects are exemplified in
detail below. It is possible for two or more of the aspects which
are arbitrarily selected from the exemplifications below to be
appropriately combined.
[0065] (1) In the embodiment described above, the target angle
.theta.x that the irradiation strength from the light emitting
section 50 becomes a peak in the imaging wavelength .lamda. was
45.degree., but the target angle .theta.x can be set to any angle
that is more than 0.degree.. However, when the target angle
.theta.x is extremely large, there is a problem that the components
that do not reach to the subject 200 because some of the imaging
light emitted from the light emitting section 50 is reflected on
the surface 222 of the substrate 22 or the components that do not
reach to the light receiving element 14 because it is reflected on
the surface 221 of the substrate 22 via the subject 200 increase
(that is, the use efficiency of the imaging light is lowered).
Therefore, for the target angle .theta.x, an angle that the
reflection on the surface 222 of the substrate 22 is appropriately
suppressed is selected as an upper limit.
[0066] FIG. 13 is a graph showing a relationship between an
incident angle of imaging light (horizontal axis) with respect to a
substrate 22 and transmittance and reflectance. The case that AN100
made by Asahi Glass Co., Ltd. (thickness of 0.5 mm) is provided as
the substrate 22 and the imaging light of 830 nm is emitted is
simulated. As shown in FIG. 13, when the incident angle is more
than 60.degree., the tendency that the reflectance steeply
increases and the transmittance steeply reduces is confirmed. In
consideration of the above tendency, it is preferred that an angle
as the target angle .theta.x is less than or equal to 60.degree..
Also, in the viewpoint that the glares or the shadows on the
surface of the subject 200 are effectively suppressed, it
empirically confirms findings that more than or equal to 30.degree.
is appropriate as the target angle .theta.x. In consideration of
the above tendency, the target angle .theta.x is appropriately
selected in the range between more than or equal to 30.degree. and
less than or equal to 60.degree..
[0067] (2) Each of the elements that were exemplified in the
embodiment described above can be properly omitted. For example, it
can be possible to omit the light blocking layer 33 or the
plurality of lenses 24. Also, a position relationship of each
element that was exemplified in the aspect described above can be
properly changed. For example, in the aspect described above, the
light emitting section 50 was formed as a top mission type light
emitting element, but when the light emitting section 50 is used as
a bottom mission type light emitting element, it is possible to
form the light source section 36 on the surface 322 of the
substrate 32. A configuration that each of the lenses 24 is
arranged between the light source section 36 and the light
receiving section 10 can be adopted. Also, it is possible that any
other element can be intervened between the respective elements
that were exemplified in the aspect described above.
[0068] (3) In the embodiment described above, the imaging apparatus
100 (a vein sensor) which images an image of veins for biological
authorization is exemplified, but the purpose of the invention is
arbitrary. For example, it is possible for the invention to be
applied to an alcohol detection apparatus which estimates the
concentration of alcohol in blood from the images of veins in a
living body which is imaged by the imaging apparatus 100 or a
medical equipment such as a blood sugar value estimation apparatus,
and the like which estimates a blood sugar value from the images of
veins in a body which is imaged by the imaging apparatus 100. For
the blood alcohol concentration estimation by using an imaging
result, or the blood sugar level estimation by using an imaging
result, the technologies known to public are arbitrarily adopted.
In addition, it is possible to apply the invention to an image
reading apparatus which reads an image from a printout. Here,
visible light is preferably used as imaging light in a case where
the invention is applied to the image reading apparatus.
[0069] In the embodiment described above, the first resonant length
and the second resonant length are set so as to match between the
peak wavelength (e.g., peak wavelength .lamda.1) of the irradiation
intensity from the light emitting section in the direction inclined
with respect to the reference direction and the peak wavelength
(e.g., peak wavelength .lamda.2) of the irradiation intensity from
the transmissive section with respect to the reference direction.
In the above aspect, it becomes particularly remarkable for the
effect that a fine and clear image of a subject can be taken while
suppressing glares and shadows of the surface of the subject. By
the way, the phrase "the peak wavelength of the irradiation
intensity from the light emitting section and the peak wavelength
of the irradiation intensity from the transmissive section are
matched" means that in addition to the case that each peak
wavelength is totally matched, it includes the case that each peak
wavelength is substantively matched (for example, in a case that
their difference is within a range of manufacturing error).
[0070] In the embodiment described above, the imaging apparatus is
provided with a plurality of lenses which is arranged in the
subject side of the light source section so that the incident light
from the subject side is focused to each of the light receiving
elements. In the above aspect, the plurality of lenses s arranged
so that the incident light from the subject side is focused to each
of the light receiving elements. Thus, it is possible to improve
the use efficiency of the imaging light in comparison with a
configuration that the incident light from the subject is not
focused.
[0071] In the embodiment described above, an angle in an
irradiation direction with respect to a reference direction (e.g.,
target angle .theta.x) is more than or equal to 30.degree. and less
than or equal to 60.degree. (for example, 45.degree.). According to
the configuration described above, it is possible to suppress
glares or shadows while the use efficiency of the incident light
from the light emitting section maintains in a high level.
[0072] In the embodiment described above, the reflection layer of
the light emitting section includes a basic reflection layer having
light reflectivity, and a dielectric multilayer film. The first
semi-transmissive reflection layer of the transmissive section
includes the dielectric multilayer film and it does not include the
basic reflection layer. According to the configuration described
above, the dielectric multilayer film of the reflection layer of
the light emitting section and the dielectric multilayer film of
the first semi-transmissive reflection layer of the transmissive
section are formed in the same layer so that it has an advantage
that the manufacturing process is simplified in comparison with the
case that the reflection layer of the light emitting section and
the first semi-transmissive reflection layer of the transmissive
section are formed independently of each other. Also, by the
configuration that the dielectric multilayer film includes a layer
formed by amorphous silicon, visible light is blocked by the layer
of the amorphous silicon so that it has an advantage that it is not
necessary to independently provide an optical filter that blocks
the visible light.
[0073] In the embodiment described above, the semi-transmissive
reflection layer of the light emitting section and the second
semi-transmissive reflection layer of the transmissive section are
formed in the same process and are formed by a material having
light reflectivity. In the above configuration, the
semi-transmissive reflection layer and the second semi-transmissive
reflection layer of the transmissive section are formed in the same
process so that it has an advantage that the manufacturing process
is simplified in comparison with the case that the
semi-transmissive reflection layer and the second transmissive
reflection layer are formed independently of each other. A
reflection conductive layer used as the semi-transmissive
reflection layer and the second transmissive reflection layer is
formed by the mixture of, for example, magnesium and silver. It is
particularly preferable that the ratio of silver is more than the
ratio of magnesium.
[0074] In the embodiment described above, the first translucent
layer of the light emitting section includes a transparent
electrode layer, which has light permeability, and light emitting
layer. The second translucent layer of the transmissive section
includes the light emitting layer and does not include the
transparent electrode layer. According to the configuration
described above, the light emitting layer of the first translucent
layer of the light emitting section and the light emitting layer of
the second translucent layer are formed in the same layer so that
it has an advantage that the manufacturing process is simplified in
comparison with the case that the first translucent layer of the
light emitting section and the second translucent layer are formed
independently of each other.
[0075] The imaging apparatus according to each of the aspects
described above is preferably used in various types of electronic
equipment. Specific examples of the electronic equipment include a
biometric authentication apparatus which executes biometric
authentication using an image of veins which has been imaged by the
imaging apparatus, and a medical equipment (a biometric information
estimating apparatus such as a blood alcohol concentration
estimating apparatus, a blood sugar level estimating apparatus, and
the like) which estimates biometric information for blood alcohol
concentration, blood sugar level, and the like from images which
have been imaged by the imaging apparatus.
* * * * *