U.S. patent application number 14/843499 was filed with the patent office on 2016-09-01 for imaging apparatus.
The applicant listed for this patent is KABUSHIKI KAISHA TOSHIBA. Invention is credited to Hideyuki FUNAKI, Koichi ISHll, Kazuhiro SUZUKI, Risako UENO.
Application Number | 20160254309 14/843499 |
Document ID | / |
Family ID | 56739936 |
Filed Date | 2016-09-01 |
United States Patent
Application |
20160254309 |
Kind Code |
A1 |
UENO; Risako ; et
al. |
September 1, 2016 |
IMAGING APPARATUS
Abstract
An imaging device includes a light source which irradiates an
infrared light including one or more wavelength to a subject; a
lens which forms an image of the infrared light transmitting the
subject or being reflected from the subject; an infrared detection
device including a plurality of pixels which are sensitive to the
wavelength; and a filter array which is provided in proximity to
the infrared detection device between the lens and the infrared
detection device and including a plurality of wavelength filters
having different transmission wavelengths.
Inventors: |
UENO; Risako; (Tokyo,
JP) ; ISHll; Koichi; (Kawasaki, JP) ; SUZUKI;
Kazuhiro; (Tokyo, JP) ; FUNAKI; Hideyuki;
(Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KABUSHIKI KAISHA TOSHIBA |
Tokyo |
|
JP |
|
|
Family ID: |
56739936 |
Appl. No.: |
14/843499 |
Filed: |
September 2, 2015 |
Current U.S.
Class: |
250/332 |
Current CPC
Class: |
H01L 27/14625 20130101;
H01L 27/14627 20130101; H01L 27/14649 20130101; H01L 27/14621
20130101 |
International
Class: |
H01L 27/146 20060101
H01L027/146 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 27, 2015 |
JP |
2015-038387 |
Claims
1. An imaging device comprising: a light source which irradiates an
infrared light including one or more wavelengths to a subject; a
lens which forms an image of the infrared light transmitting the
subject or being reflected from the subject; an infrared detection
device including a plurality of pixels which are sensitive to the
wavelength; and a filter array which is provided in proximity to
the infrared detection device between the lens and the infrared
detection device and including a plurality of wavelength filters
having different transmission wavelengths, wherein the filter array
of the plurality of wavelength filters has transmission wavelengths
that change continuously in one direction on a plane and that are
the same as each other in a different direction which is orthogonal
to the one direction.
2. The imaging device as claimed in claim 1, wherein the infrared
detection device and the filter array are laminated to be
integrated.
3. (canceled)
4. The imaging device as claimed in claim 1, wherein, in the filter
array, one or more groups into which the plurality of wavelength
filters having the different transmission wavelengths are combined
are arranged in a two-dimensional array.
5. The imaging device as claimed in claim 1, wherein, the filter
array has a structure in which a resonance layer and an
interference layer are laminated; and the resonance layer and the
interference layer are arranged such that the resonance layer is
located on the image-forming optical member side and the
interference layer is located on the infrared detection device
side.
6. The imaging device as claimed in claim 5, wherein the resonance
layer is a metal pattern layer having a periodic structure that is
made of a metal thin film.
7. The imaging device as claimed in claim 6, wherein the metal thin
film is made of any one metal or an alloy of at least two types of
metals of a group consisting of aluminum, silver, gold, tungsten,
and copper.
8. The imaging device as claimed in claim 5, wherein the
interference layer includes a sympathetic vibration layer formed of
a high-reflectance material and a transmission layer formed of a
low-reflectance material.
9. The imaging device as claimed in claim 8, wherein the
high-reflectance material is silicon or germanium.
10. The imaging device as claimed in claim 8, wherein the
low-reflectance material is any one of silicon oxide, zinc
selenide, and zinc sulfide.
11. The imaging device as claimed in claim 6, wherein, for the
wavelength transmission filters, the transmission wavelengths
differ depending on a pattern period of the metal pattern
layer.
12. The imaging device as claimed in claim 6, further comprising a
light shielding layer which is formed with the same metal thin film
as that of the metal pattern layer.
13. The imaging device as claimed in claim 1, wherein the infrared
detection device includes a semiconductor substrate; a micro
bolometer array which is provided on the semiconductor substrate;
and a support substrate, wherein the semiconductor substrate and
the support substrate are laminated such that the micro bolometer
array is sealed therebetween.
14. The imaging device as claimed in claim 13, wherein the filter
array is laminated on the semiconductor substrate side of the
infrared detection device.
15. The imaging device as claimed in claim 14, wherein the
semiconductor substrate is formed in a lens shape.
16. The imaging device as claimed in claim 13, wherein the filter
array is provided on the support substrate.
17. The imaging device as claimed in claim 1, wherein at least two
of a light source, an image-forming optical member, an infrared
detection device, and the wavelength transmission filter array
cause a processor to perform material identification of the subject
and cause an image information synthesis processor to obtain image
information of the subject to be obtained from wavelength
information of the infrared detection device.
18. An imaging device comprising: a light source which irradiates
an infrared light including one or more wavelengths to a subject; a
lens which forms an image of the infrared light transmitting the
subject or being reflected from the subject; an infrared detection
device including a plurality of pixels which are sensitive to the
wavelength; and a filter array which is provided in proximity to
the infrared detection device between the lens and the infrared
detection device and including a plurality of wavelength filters
having different transmission wavelengths, wherein the filter array
has a structure in which a resonance layer and an interference
layer are laminated; and wherein the resonance layer and the
interference layer are arranged such that the resonance layer is
located on the image-forming optical member side and the
interference layer is located on the infrared detection device
side.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from Japanese Patent Application No. 2015-038387, filed
Feb. 27, 2015; the entire contents of which are incorporated herein
by reference.
FIELD
[0002] Embodiments described herein relate generally to a solid
imaging apparatus.
BACKGROUND
[0003] Far Infrared (FIR; 8 to 15 .mu.m) region is an
electromagnetic wavelength band having a black body radiation
intensity peak in the vicinity of the human body temperature. On
the other hand, Mid Infrared (MIR; 3 to 5 .mu.m) region, which is
on the side of shorter wavelengths relative to the FIR, is an
electromagnetic wavelength band having a black body radiation
intensity peak at a relatively high temperature of between 200 and
400.degree. C.
[0004] In connection with the above-described black body radiation
intensity, techniques for detecting electromagnetic waves in the
MIR region is used mainly for detecting high temperature objects
and for detecting at the fire site, etc. On the other hand, there
is a material-specific absorption peak due to rotation and
vibration of molecules in the whole MIR and FIR regions. In
particular, information on the molecular structure is obtained by
obtaining the IR spectrum in the 2 to 20 .mu.m band. More
precisely, whether a certain functional group (alcohol, amine,
ketone, aliphatic, etc.) is present can be identified; information
sets on appearance of absorption in certain wavelengths may be
combined to check against a database to perform material
identification.
[0005] Infrared spectroscopic analysis techniques using the
above-described MIR-FIR regions, including the FT-IR analysis
technique, are widely used in analysis such as organic chemical
analysis. FT-IR apparatuses (spectroscopy: Michelson's
interferometer, detector: a cooling-type MCT, etc.), apparatuses
which are superior in the precision for wavelength analysis and
widely used, are analyzers for obtaining information on simple
substance samples and are not for obtaining spatial distribution
(camera image information). Moreover, most of the so-called
infrared spectrometers (spectroscopy: a filter, etc., detector: a
cooling-type MCT, etc.) are also for obtaining the information on
the simple substance samples. On the other hand, while attention is
focused on infrared spectropic microscopes for obtaining image
information and the infrared spectrum of an image point thereof,
they are quite expensive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a system diagram illustrating a configuration of a
solid imaging apparatus according to a first embodiment;
[0007] FIG. 2 is a cross-sectional view illustrating an imaging
module which makes up the solid imaging apparatus according to the
first embodiment;
[0008] FIG. 3 is an enlarged cross-sectional view illustrating a
configuration of a major part of the imaging module according to
the first embodiment;
[0009] FIG. 4 is a plan view illustrating a pattern of a resonance
layer according to the first embodiment;
[0010] FIG. 5 is a perspective view illustrating the plane
structure of an imaging module 6 according to the first
embodiment;
[0011] FIG. 6 is a schematic view illustrating the correspondence
between a transmission wavelength band (.lamda..sub.i) and spectral
data;
[0012] FIG. 7 is a schematic view illustrating a method of material
identification of a subject and a method of obtaining
two-dimensional image information using the solid imaging apparatus
according to the first embodiment;
[0013] FIG. 8 is a plan view illustrating a smartphone in which the
solid image apparatus is embedded;
[0014] FIG. 9 is a plan view illustrating a tablet terminal in
which the solid image apparatus is embedded;
[0015] FIG. 10 is a plan view illustrating one example of an
automobile in which are provided the solid imaging apparatus and an
image display apparatus;
[0016] FIG. 11 is a plan view illustrating another example of the
automobile in which are provided the solid imaging apparatus and
the image display apparatus;
[0017] FIG. 12 is a schematic view illustrating the correspondence
between a two-dimensional arrangement diagram of a group in which
multiple filters of different transmission wavelength bands are
combined as one set and spectral data;
[0018] FIGS. 13A to 13D are plan views illustrating other exemplary
patterns of the resonance layer;
[0019] FIG. 14 is an enlarged cross-sectional view illustrating the
configuration of the major part of the imaging module according to
a second embodiment;
[0020] FIG. 15 is an enlarged cross-sectional view illustrating the
configuration of the major part of the imaging module according to
a third embodiment;
[0021] FIG. 16 is an enlarged cross-sectional view illustrating the
configuration of the major part of the imaging module according to
a fourth embodiment;
[0022] FIG. 17 is an enlarged cross-sectional view illustrating the
configuration of the major part of the imaging module according to
a fifth embodiment; and
[0023] FIG. 18 is a system diagram illustrating a configuration of
a variation of the solid imaging apparatus.
DETAILED DESCRIPTION
[0024] According to some embodiments, an imaging device includes a
light source; a lens; an infrared detection device; and a filter
array. The lens forms an image of an infrared light transmitting a
subject or being reflected from the subject. The infrared detection
device includes a plurality of pixels which are sensitive to a
wavelength. The filter array is provided in proximity to the
infrared detection device between the lens and the infrared
detection device and includes a plurality of wavelength filters
having different transmission wavelengths.
[0025] Various embodiments of the imaging device or a solid image
apparatus will be described hereinafter with reference to the
accompanying drawings.
[0026] The drawings used in the description hereinafter may be
shown with parts to be characteristic features enlarged for the
sake of convenience, so that the dimension ratios of the respective
constituting elements are not necessarily the same as the actual
ones.
First Embodiment
[0027] First, an exemplary configuration of a solid imaging
apparatus according to a first embodiment is described.
[0028] FIG. 1 is a system diagram illustrating a configuration of
the solid imaging apparatus according to the first embodiment. As
illustrated in FIG. 1, a solid imaging apparatus 1 according to the
present embodiment includes a light source 2 which irradiates an
infrared light I.sub.o onto a subject (an object to be measured) S;
a lens (an image-forming optical member) 3 which forms an image of
an infrared light I which transmits the subject S; and an imaging
module 6 in which an infrared detection device 4 and a wavelength
transmission filter array 5 are integrated. The solid imaging
apparatus 1 according to the present embodiment is an active-type
infrared hyperspectral imaging apparatus in which material
identification of and image information on the subject S is
obtained from wavelength information obtained with the imaging
module 6 (the infrared detection device 4).
[0029] The light source 2 is a thermal type (a non-dispersion type)
light source which irradiates the infrared light I.sub.o including
wavelength bands (.lamda..sub.C1 to .lamda..sub.C2) to be detected
onto the subject S. Here, the wavelength bands (.lamda..sub.C1 to
.lamda..sub.C2) are not limited thereto as long as they include
mid-infrared to far-infrared regions (in other words, 2 .mu.m to 30
.mu.m). The light source 2 as described above includes an
incandescent filament, a filament-type infrared light source, a
ceramic high-luminance light source, a halogen lamp, a
high-pressure mercury light source, for example.
[0030] The lens 3 is an image-forming optical member which
functions as an optical imaging system which takes the infrared
light I from the subject (the object to be measured) into the
infrared detection device 4. The lens 3 is not limited thereto as
long as it may project the intensity of light collected at the
respective spatial locations (X, Y, Z) as an image.
[0031] In the imaging module 6, the infrared detection device 4 and
the wavelength transmission filter array 5 are laminated to be
integrated. The imaging module 6 functions as a device which
converts the intensity of the infrared light I collected by the
lens (image-forming member) 3 to a voltage of a signal and outputs
the signal.
[0032] The infrared detection device 4 is a two-dimensional
infrared detection sensor in which multiple pixels are arranged in
a two-dimensional array on an X-Y plane to obtain image
information. For the multiple pixels, micro bolometers, etc., are
used as thermoelectric conversion device, for example.
[0033] FIG. 2 is a cross-sectional view illustrating the imaging
module 6 which makes up the solid imaging apparatus 1 according to
the present embodiment. As illustrated in FIG. 2, the imaging
module 6 is generally configured such that a wavelength
transmission filter array layer 7, an infrared detection device
layer 8, and a support layer 9 that are included therein are
laminated. Moreover, the imaging module 6 includes multiple regions
including an imaging region and peripheral circuit regions.
[0034] The wavelength transmission filter array layer 7 includes
the wavelength transmission filter array 5, which is provided in
the imaging region.
[0035] In the imaging region of the infrared detection device layer
8, there is provided a non-cooling type infrared detector (an
optical detector) 10 which includes an array of micro bolometers,
for example. Here, the micro bolometer converts incident infrared
light to heat with an infrared absorber and then converts, by a
thermoelectric converter, a temperature change in a thermal sensor
that is caused due to the weak heat to an electrical signal and
read the electrical signal to obtain infrared image information.
Depending on the material of the above-described infrared absorber,
infrared light of a wide wavelength bandwidth (for example, 3 .mu.m
to 30 .mu.m) may be absorbed, allowing a configuration which is
sensitive in a wavelength bandwidth which is higher than that for a
compound-type solid imaging device such as MCT (mercury cadmium
telluride; HgCdTe) in which a sensitivity wavelength is determined
by a material-specific band gap.
[0036] On the other hand, the peripheral circuit regions of the
infrared detection device layer 8 includes a read circuit 11; a
wiring layer 12; a through electrode 13 which is an electrode to
the exterior; an electrode pad 14; a light shielding layer 15
including a light-shielding metal film which prevents unnecessary
light from penetrating, etc.
[0037] The support layer 9, which includes a support substrate 16,
is bonded with the infrared detection device layer 8 via a support
substrate bonding section 17. In other words, the infrared
detection device layer 8 and the support layer 9 are laminated to
form the infrared detection device 4.
[0038] Now, in the infrared detection device layer 8, it is
necessary to thermally separate, from the surroundings, the optical
detector 10 (including the infrared absorption structure and the
thermoelectric converter) which converts incident infrared light to
heat to convert the heat to an electrical signal to improve the
thermoelectric conversion efficiency. Then, the infrared detection
device layer 8 is configured such that a device separating oxide
film and a silicon substrate around the optical detector 10 are
removed by etching to create a cavity section 18 which is made to
be a vacuum to prevent heat from dispersing into the support
substrate 16.
[0039] In the imaging region is provided valid pixels and reference
pixels (not shown). Here, the reference pixels, which refer to an
OB (Optical Black), a TB (Thermal Black), etc., are used to refer
to black levels (offset levels), respectively. At an upper portion
of the optical black pixel is formed a light-shielding metal film.
This light-shielding metal film may be formed of the same metal as
the below-described metal pattern layer.
[0040] On the other hand, in the periphery circuit regions is
provided a drive circuit (not shown) which drives the respective
pixels of a pixel array of the imaging device; and a pixel signal
processing circuit (not shown) which processes a signal output from
a pixel region.
[0041] The drive circuit includes, for example, a vertical
selection circuit which successively selects a pixel to be driven
in the vertical direction in horizontal lines (rows); a horizontal
selection circuit which successively selects in columns; a TG
(Timing Generator) circuit which drives them with various
pulses.
[0042] The above-described pixel signal processing circuit includes
an AD conversion circuit which digitally converts an analog
electric signal from the pixel region; a gain
adjustment/amplification circuit which performs gain adjustment and
amplification operation, a digital signal processing circuit which
performs a process for correcting the digital signal.
[0043] FIG. 3 is an enlarged cross-sectional view (X-Z plane view)
illustrating an exemplary configuration of a major part of the
imaging module 6. As illustrated in FIG. 3, the infrared detection
device layer 8 includes a semiconductor substrate 19 on which
surface is provided the cavity section 18, which is a vacuum; a
wiring 20 which is formed in a region surrounding the cavity
section 18 of the semiconductor substrate 19; a support leg 21
which is connected to the wiring 20 and which is arranged on the
cavity section 18 of the semiconductor substrate 19 inside the
wiring 20; and the optical detector 10, which is connected to the
support leg 21 to be supported on the cavity section 18 of the
semiconductor substrate 19 inside the support leg 21.
[0044] The wavelength transmission filter array layer 7 is
laminated on the side of the semiconductor substrate 19 which makes
up the infrared detection device layer 8. Moreover, the wavelength
transmission filter array layer 7, which includes a resonance layer
22 and an interference layer 23, is configured such that the
resonance layer 22 and the interference layer 23 are laminated in
the order of the resonance layer 22, followed by the interference
layer 23, when viewed from the side of the light-incident
direction, or, in other words, the positive direction of the Z-axis
shown in FIG. 3.
[0045] The resonance layer 22 includes metal pattern layers 22A and
22B of the periodic structure that are formed of metal thin films;
and the light shielding layer 15. While the material (in other
words, metal) of the metal thin film is not specifically limited,
aluminum (Al), silver (Ag), gold (Au), tungsten (W), copper (Cu),
and alloys thereof may be used, for example.
[0046] The metal pattern layers 22A and 22B and the light shielding
layer 15 may be formed of the same metal thin film, or may be
formed of different metal thin films.
[0047] FIG. 4 is a plan view (X-Y plane view) illustrating an
exemplary pattern of the resonance layer 22. As shown in FIG. 4,
the metal pattern layers 22A and 22B are configured such that
rectangular (generally square) shaped metal patterns made of a
metal thin film are arranged in a two-dimensional array shape with
a predetermined pattern period (pitch) and an inter-pattern
interval. On the other hand, the whole face of the light shielding
layer 15 is covered with a metal pattern.
[0048] In a pixel region (1) the metal pattern layer 22A has a
pattern period (.GAMMA..sub.A) and an inter-pattern interval
(s.sub.A). Moreover, in a pixel region (2) the metal pattern layer
22B has a pattern period (.GAMMA..sub.B) and an inter-pattern
interval (s.sub.B).
[0049] Now, a pattern period (.GAMMA.) of a metal pattern with the
metal pattern layers 22A and 22B as one example is known to
determine a Surface Plasmon Polariton (SPP) infrared light
resonance wavelength. Then, a light of a wavelength band in which
resonance occurs transmits therethrough to function as a wavelength
transmission filter.
[0050] Here, the above-described SPP refer to the plasmons, which
are oscillations of free electrons in metal; and plaritons, in
which lights which move within the dielectric couple, are
compression waves which passes through the interface. For example,
the wave number k.sub.x of the SPP when it passes in the X
direction through an interface between the dielectric
(permittivity: .di-elect cons..sub.d) and the metal (permittivity:
.di-elect cons..sub.m) at Z=0 is shown with the following Equation
(1):
k x = .omega. c ( m .times. d ) ( m + d ) Equation ( 1 )
##EQU00001##
[0051] In the above Equation (1), w refers to an angular frequency
(1/s), while c refers to velocity of light (m/s).
[0052] The above-described SPP is characterized by containment into
the boundary face and enhancement of the electric field in the
vicinity of the interface. Therefore, in the above-described
Equation (1), the relationship of the Equation (2) below needs to
be satisfied:
.di-elect cons..sub.d+.di-elect cons..sub.m<0 Equation (2)
[0053] The permittivity .di-elect cons..sub.m of the metal, which
varies with .omega., is shown with a function .di-elect cons..sub.m
(.omega.). It is shown in Equation (3) below using a plasma
frequency .omega..sub.p:
m ( .omega. ) = 1 - ne 2 0 m .omega. 2 = 1 - .omega. p 2 .omega. 2
Equation ( 3 ) ##EQU00002##
[0054] Therefore, in accordance with (2) and (3) in the above,
.omega. at which the SPP is present is shown with the following
Equation (4):
.omega. < .omega. p 1 + d Equation ( 4 ) ##EQU00003##
[0055] On the other hand, the SPP is a vertical wave, and may not
be excited just by irradiating a p-polarized light onto a metal
thin film from inside the vacuum, so that the wave number k.sub.x
needs to be increased. To increase the wave number for excitation,
a grating structure is used; the grating of the wave number k.sub.g
(the convexo-concavity of the period (.GAMMA.)) is shown as
k.sub.g=2.pi./.GAMMA.. When the result of adding n times the
integer and the incident light wave number (k.sub.x=2.pi. sin
.theta./.lamda..sub.in) matches the wave number
(k.sub.SPP=2.pi./.lamda..sub.SPP) of the SPP (in other words, when
the relationship in Equation (5) below is satisfied), the incident
light and the SPP couple to cause the SPP of the resonance wave
length .lamda..sub.spp to be excited.
k spp = 2 .pi. .lamda. in sin .theta. + n 2 .pi. .GAMMA. Equation (
5 ) ##EQU00004##
[0056] As described above, for the respective wavelength
transmission filters, the pattern period (.GAMMA.) of the metal
pattern determines the transmission center wavelength
.lamda..sub.i. Moreover, the interval (s) between the metal
patterns affects the half-value width of the transmission
wavelength, the transmittance, etc. The principle of the SPP can be
applied not only in the one-dimensional direction, but also in the
two-dimensional direction.
[0057] As illustrated in FIG. 3, the interference layer 23 includes
a sympathetic vibration layer 24 with film thicknesses d.sub.a2,
d.sub.b2 and a transmission layer 25 with film thicknesses
d.sub.a1, d.sub.b1. Moreover, the interference layer 23 is
configured such that the sympathetic vibration layer 24 and the
transmission layer 25 are laminated in the order of the sympathetic
vibration layer 24, followed by the transmission layer 25, when
viewed from the side of the light-incident direction (the positive
direction of the Z-axis shown in FIG. 3).
[0058] For the film which makes up the sympathetic vibration layer
24, the material thereof is not limited thereto as long as it has
the transmittance of a desired infrared region that is sufficiently
high and has high reflectance. Such high-reflectance materials
include silicon (Si), germanium (Ge), gallium arsenide (GaAs), for
example.
[0059] For the film which makes up the transmission layer 25, the
material thereof is not limited thereto as long as it has the
transmittance of a desired infrared region that is sufficiently
high and has low reflectance. Such low-reflectance materials
include silicon oxide film (SiO.sub.2), zinc selenide (ZnSe), zinc
sulfide (ZnS), for example. Moreover, as the low-reflectance
material, silicon (Si) may be subjected to a fine concave-convex
process to less than or equal to the infrared wavelength and embed
the low-reflectance material into a hole thereof to make a
low-reflectance material.
[0060] The film thickness of the sympathetic vibration layer 24 and
the transmission layer 25 that make up the interference layer 23 is
designed with the transmission center wavelength .lamda..sub.i.
[0061] For example, in the sympathetic vibration layer 24, with the
reflectance of the material it is formed of being set to n.sub.d2,
it is desirable to set the film thickness d.sub.2 such that
d.sub.2=.lamda..sub.i/2n.sub.d2. The film thickness may be set to
the one-half wavelength of the optical film thickness to cause
sympathetic vibration within the thin film of the sympathetic
vibration layer 24, thereby increasing the transmittance.
[0062] On the other hand, in the transmission layer 25, to prevent
reflection of the wavelength of .lamda..sub.i and increase the
transmittance, it is desirable to set the film thickness
d.sub.1=.lamda..sub.i/4n.sub.d1 with the reflectance of the
material it is formed of being set to n.sub.d1.
[0063] As shown in FIGS. 3 and 4, the imaging module 6 according to
the present embodiment is provided with a filter which causes
different transmission wavelengths, and .lamda..sub.b to be
transmitted for the pixel regions (1) and (2). In other words, the
wavelength transmission filter array layer 7 includes multiple
filters which transmit respectively different wavelengths; with
these filters, the pattern period (.GAMMA.) of the metal pattern
layers 22A, 22B which make up the resonance layer 22 and the film
thicknesses d.sub.1 and d.sub.2 of the sympathetic vibration layer
24 and the transmission layer 25 that make up the interference
layer 23 are adjusted by the transmission center wavelength
.lamda..sub.i.
[0064] FIG. 5 is a perspective view illustrating the plane
structure of the imaging module 6 which makes up the solid imaging
apparatus 1 according to the present embodiment. Moreover, FIG. 6
is a schematic view illustrating the correspondence between a
transmission wavelength band (.lamda..sub.i) and spectral data.
[0065] As shown in FIG. 5, in the imaging module 6, the infrared
detection device layer 8 (infrared detection device 4) and the
wavelength transmission filter array layer 7 (wavelength
transmission filter array 5) are laminated to be integrated.
Moreover, in the wavelength transmission filter array 5, multiple
wavelength transmission filters with different transmission
wavelength bandwidths are arranged on an X-Y plane.
[0066] The plane structure of the infrared detection device layer 8
includes an imaging region 26; and a peripheral circuit region 27,
which includes a read circuit 28. Moreover, the imaging region 26
is a two-dimensional infrared detector in which infrared light
detectors 29 are two-dimensionally arranged.
[0067] In the imaging module 6 which makes up the present
embodiment, the wavelength transmission filter array 5, which is a
filter which transmits the same wavelength band in the Y direction,
is a linear variable filter (LVF) whose transmission wavelength
gradually changes in the X direction. In other words, in the
wavelength transmission filter array 5, wavelength transmission
filters whose transmission wavelength bandwidths continuously
change are arranged in the X direction on the X-Y plane, while
those whose transmission wavelength bandwidths are the same are
arranged in the Y direction.
[0068] As illustrated in FIG. 6, when the transmission wavelength
changes in the one-dimensional direction (X direction), the light
intensity I obtained has a relationship such that, with the
detection coordinates of the infrared detection device layer 8,
which is a two-dimensional infrared detection sensor, being set to
(x, y), the intensity thereof is represented as I (x=.lamda..sub.i,
y), and x corresponds to the wavelength .lamda..sub.i.
[0069] Next, an exemplary method of manufacturing the imaging
module 6, which is a major part of the solid imaging apparatus 1
according to the present embodiment, is described.
[0070] First, as illustrated in FIGS. 2 and 3, in the pixel region
(imaging region) on the one face side of the semiconductor
substrate 19, the optical detector 10, the wiring 20, and a wiring
of the support leg 21 are formed. On the other hand, in the
peripheral circuit region, there are formed, at the same time, the
read circuit 11, the wiring layer 12, the through electrode 13, and
the electrode pad 14. Then, the support leg 21 is formed with a
trench process technique and a lower portion of the optical
detector 10 is etched with an anisotropic etching technique, etc.,
to separate the etched result from the semiconductor substrate 19,
and form the cavity section 18 to be a vacuum. In this way, the
infrared detection device layer 8 is formed.
[0071] Next, bonding of the support layer (support substrate) 9 and
the infrared detection device layer 8 is performed in a high vacuum
and the cavity section 18 of the infrared detection device layer 8
is made to be a high vacuum. In this way, dispersion of heat into
the support substrate 16 and the semiconductor substrate 19 is
suppressed and the sensitivity to the infrared light of the optical
detector (infrared detector) 10 is increased.
[0072] Next, as illustrated in FIG. 3, a coating of a
low-reflection material is formed and film thicknesses in the pixel
region (1), the pixel region (2), and the peripheral circuit region
are adjusted by etching, etc., to form the transmission layer 25 on
the other side of the semiconductor substrate 19. Next, a coating
of a high-reflection material is formed on a surface of the
transmission layer 25 and the thicknesses are similarly adjusted to
form the sympathetic vibration layer 24. In other words, the
interference layer 23 which is made up of the transmission layer 25
and the sympathetic vibration layer 24 is formed.
[0073] Next, a metal coating is formed on a surface of the
interference layer 23, and, collectively, the metal pattern layer
22A having the pattern period (.GAMMA..sub.A) and the inter-pattern
interval (s.sub.A) is formed in the pixel region (1), the metal
pattern layer 22B having the pattern period (.GAMMA..sub.B) and the
inter-pattern interval (s.sub.B) is formed in the pixel region (2),
and the light shielding layer 15 is formed for the reference pixel.
In this way, the wavelength transmission filter array layer 7 which
is made up of the interference layer 23 and the metal pattern layer
22 is formed. In other words, the wavelength transmission filter 5
is laminated on the semiconductor substrate 19 which makes up the
infrared detection device 4 to integrate the laminated results.
[0074] The imaging module 6 may be manufactured in the
above-described manner.
[0075] Next, an example of a method of using the solid imaging
apparatus 1 according to the present embodiment, or, in other
words, a method of material identification of a subject and a
method of obtaining two-dimensional image information are
described.
[0076] FIG. 7 is a schematic view illustrating the method of
material identification of the subject and the method of obtaining
the two-dimensional image information using the solid imaging
apparatus 1.
[0077] As illustrated in FIG. 1, first an infrared light I.sub.o is
irradiated from a thermal type (non-dispersion type) light source
2. Here, step S1 shown in FIG. 7 shows a relationship between the
intensity and the wavelength of the infrared light I.sub.o
irradiated from the light source 2.
[0078] Next, as illustrated in FIG. 1, the infrared light I.sub.o
irradiated from the light source 2 transmits the object to be
measured (subject) S. Here, step S2 shown in FIG. 7 shows a
relationship between the intensity and the wavelength of the
infrared light I which transmitted the object to be measured S. As
shown in step S2, in a wavelength band (.DELTA..lamda.) in which
absorption occurred in the object to be measured, the light
intensity of the transmitted spectrum decreases in accordance with
the absorption characteristics of the object to be measured.
[0079] Next, as illustrated in FIG. 1, with the infrared light I
which transmitted the object to be measured S being collected with
the lens 3 and the coordinates of a sensor face onto which the
light intensity at the respective spatial positions (X, Y, Z) is
projected as an image being set as (x,y), the intensity decrease is
sampled in the imaging module 6 with the image light intensity
being set as I (x,y). Here, step S3 shown in FIG. 7 shows spectral
information (wavelength information) obtained in a certain row (Yi)
of the imaging module 6.
[0080] The solid imaging apparatus 1 according to the present
embodiment makes it possible, from wavelength information obtained
by the imaging module (infrared detection device) 6, to
discriminate a material of the object to be measured (subject) S to
identify the discriminated results and obtain image information on
the subject S. The method of material identification and the method
of image synthesis are separately described below.
[0081] First, an exemplary method is described of discriminating
the material from the absorption characteristics in the infrared
region of molecules and the material.
[0082] Various functional groups have specific absorption
intensities and absorption energies (wave numbers). As a trend for
the relationship between the absorption wavelength (frequency) and
the structure, first, absorption appears at the high number of
vibrations (on the short wavelength side) when a constituent atom
is light; with a stretching vibration due to a single bond with
hydrogen, such as a C--H bond, an O--H bond, an N--H bond, hydrogen
is light, so that absorption appears at the high number of
vibrations (short wavelength). Thus, conversely, when the mass of
the constituent atom increases, absorption appears on the low
frequency (long wavelength) side.
[0083] When a bond of two atoms is strong, absorption also appears
at the high number of vibrations (on the short wavelength side).
For example, with a triple bond, absorption appears at a frequency
which is higher than that with a double bond or a single bond;
while absorption appears at the wave number 2200 cm.sup.-1.
(.lamda.=4.55 .mu.m) with the triple bond (C.ident.C), it appears
at the wave number 1640 cm.sup.-1 (.lamda.=6.1 .mu.m) with the
double bond (C.ident.C) and at the wave number 1000 cm.sup.-1
(.lamda.=10 .mu.m) with the single bond (C--C).
[0084] Numerous gases (gas molecules) are also present which
exhibit absorption in infrared. For example, alcohols (methanol,
ethanol, etc.) and CO.sub.2, CO, NO.sub.X, SO.sub.2, etc., are
representative gas molecules which exhibit strong absorption in the
infrared region. On the other hand, molecules having a center of
symmetry (H.sub.2, O.sub.2, N.sub.2, etc.) do not exhibit infrared
absorption. This is because the infrared absorption is caused by
the dipole moment changing due to molecular vibrations and the
changed dipole moment interacting with the electric vector of the
light.
[0085] To obtain these molecular absorption spectra information
sets, an infrared light is irradiated from a continuous light
source for measurement; the intensity thereof is decreased in a
wavelength band in which a sample exhibits absorption, so that the
decrease in the intensity is measured in the whole wave number
(wavelength) region. A filter which only passes a transmission
width .DELTA..lamda. may be used to detect it for the respective
wavelength band (.DELTA..lamda.).
[0086] As shown in FIG. 7, the obtained spectra are sent to a
processor 30. In the processor 30, the spectral information is
checked against a spectral information database 31 and the
similarities of the intensity and the position of the absorption
band are compared to perform compound identification. Then, as
shown in step S4 in FIG. 7, results of material identification of
the object to be measured S is obtained from the processor 30.
[0087] Next, an exemplary method of spectral image synthesis is
described.
[0088] To obtain complete spectral information .GAMMA.(x, y,
.lamda.) on the image coordinates (x, y) onto which the subject S
is projected, the solid image apparatus 1 or the subject S is swept
in the X direction to perform continuous shooting. For synthesis
and connection, HS (Hyperspectral) images themselves may be
synthesized, or, with a visible camera being embedded into a camera
apparatus, the HS images may be synthesized based on a visible
viewpoint. The method of synthesis and connection of
one-dimensional filters has become a common function which is
provided in a camera, such as in a mobile telephone, with the
progress in the image processing and synthesis techniques in recent
years and is called the pushbroom technique. This technique is
arranged to not significantly impair spatial resolution even when
the number of spectral bands is substantially large.
[0089] Here, the spectral information (wavelength information) from
the imaging module 6 that is obtained by sweeping the solid image
apparatus 1 or the subject S in the X direction to perform
continuous shooting is sent to an image information synthesis
processor 32 as shown in FIG. 7. In the image information synthesis
processor 32, image information synthesis processing is performed.
Then, as shown in step S5 in FIG. 7, two-dimensional image
information on the object to be measured S is obtained from the
image information synthesis processor 32.
[0090] The processor 30, the spectral information database 31, and
the image information synthesis processor 32 that are shown in FIG.
7 may be included in the solid imaging apparatus 1, or may be
included in equipment into which the solid imaging apparatus 1 is
embedded. Moreover, the spectral information database 31 and the
image information synthesis processor 32 may be provided
externally, and, via a wired or wireless communications device,
spectral information may be transmitted from the solid imaging
apparatus 1 and results of material identification or
two-dimensional image information may be received.
[0091] The solid imaging apparatus 1 according to the first
embodiment is used for imaging apparatuses such as those in various
mobile terminals such as digital cameras, mobile telephones
(including smartphones), and monitoring cameras, web cameras using
the Internet.
[0092] FIG. 8 is a plan view illustrating a smartphone 61 including
a camera in which the solid imaging apparatus 1 according to the
present embodiment is provided. The smartphone 61 includes a camera
(not shown) and a touch panel 62. When the camera is provided in
the upper portion of the front face of the smartphone 61, for
example, the front face of the smartphone 61 may be shot. Moreover,
the touch panel 62, which is provided at the center of the front
face of the smartphone, makes it possible to display thereon an
image shot with the camera.
[0093] FIG. 9 is a plan view illustrating a tablet 71 including a
camera in which the solid image apparatus 1 according to the
present embodiment is provided. The tablet 71 includes a camera
(not shown) and a touch panel 72. When the camera is provided in
the upper portion of the front face of the tablet 71, for example,
the front face of the tablet 71 may be shot. Moreover, the touch
panel 72, which is provided at the center of the front face of the
tablet, makes it possible to display thereon an image shot with the
camera.
[0094] FIG. 10 is a perspective view illustrating one example of an
automobile 81 including a camera 82 in which is provided the solid
imaging apparatus 1 according to the present embodiment. The
automobile 81 includes the camera 82 and a display 83. The camera
82, which is provided in the front end of the automobile 81, makes
it possible to shoot the front of the automobile 81. Moreover, the
display 83, which is provided in the front face of the driver's
seat of the automobile 81, makes it possible to display an image
shot with the camera 82. The image shot with the camera 82 may be
checked with the display 83 to check the dead angle even in the
evening at the time of parking a car, for example.
[0095] FIG. 11 is a perspective view illustrating one example of an
automobile 91 including a camera 92 in which is provided the solid
imaging apparatus 1 according to the present embodiment. The
automobile 91 includes the camera 92 and a display 93. The camera
92, which is provided in the rear end of the automobile 91, makes
it possible to shoot the rear of the automobile 91. Moreover, the
display 93, which is provided in the front face of the driver's
seat of the automobile 91, makes it possible to display an image
shot with the camera 92. The image shot with the camera 92 may be
checked with the display 93 to check the rear even in the
evening.
[0096] As described above, the solid imaging apparatus 1 according
to the present embodiment is a solid imaging apparatus including
the light source 2 which irradiates an infrared light I.sub.o onto
a subject S; the lens (an image-forming optical member) 3; the
infrared detection device 4 in which multiple pixels which are
sensitive in wavelength bands to be detected are arranged in a
two-dimensional array on an X-Y plane; and the wavelength
transmission filter array 5 in which multiple wavelength
transmission filters having different transmission wavelength
bandwidths of transmission wavelength bands are arranged on the X-Y
plane, wherein the imaging module 6 is configured such that the
infrared detection device (infrared detection device layer) 4 and
the wavelength transmission filter array (wavelength transmission
filter array layer) 5 are integrated therein, so that it is
superior in material discrimination performance and allows
obtaining image information.
[0097] In the solid imaging apparatus 1 according to the present
embodiment, the wavelength transmission filter array 5 in which are
arranged wavelength transmission filters which respectively
transmit specific wavelengths is formed immediately above multiple
infrared detection pixels, so that the precision of alignment
between the wavelength transmission filter and the pixel is
improved. Therefore, reduction in the size of the equipment is made
possible.
[0098] In the solid imaging apparatus 1 according to the present
embodiment, the wavelength transmission filter array layer 7 is
arranged to include the resonance layer 22 and the interference
layer 23. Therefore, film thickness of the interference layer 23
and the size of the metal pattern in the resonance layer 22 are
changed to facilitate changing the transmission wavelength of
individual filters.
[0099] The resonance layer 22 which makes up the wavelength
transmission filter array layer 7 makes it to possible to achieve a
narrow transmission wavelength bandwidth performance. In this way,
a molecule-specific absorption peak in a close wavelength band may
be separated to further improve the material discrimination
performance.
[0100] The solid imaging apparatus 1 according to the present
embodiment may be applied to an infrared hyperspectral technique in
which sampling is made for each wavelength bandwidth. This makes it
possible to obtain advantages that it is not likely to affect the
subject to be measured or the environment. Moreover, measuring the
absorbance of light allows high speed measurement, making it
possible to conduct simultaneous measurement of multiple subjects.
Furthermore, simultaneous measurement of multiple subjects can be
conducted at multiple wavelengths to make it possible application
to fields such as warming gas measurement (refrigerant gas
measurement), exhaust gas measurement, indoor air monitoring,
breath alcohol analysis, noninvasive blood measurement, etc.
[0101] The solid imaging apparatus 1 according to the present
embodiment allows obtaining information on the above-mentioned
fields with imaging (image information), resulting in a dramatic
increase in the amount of information obtained. This makes it
possible to simultaneously detect a large number of individuals, so
that there is applicability also as an apparatus for screening,
such as detecting an intoxicated individual within a crowd.
[0102] The configuration of the solid imaging apparatus 1 according
to the present embodiment is merely exemplary.
[0103] While the configuration according to the first embodiment is
described as the one example in which the infrared light I.sub.o is
irradiated onto the subject S from the light source 2, and an image
of the infrared light I which transmits the subject S is formed
with the lens 3 to detect the formed image with the imaging module
6, or, in other words, the infrared detection device 4, there is
also applicability to a configuration in which an image of the
infrared light which is reflected from the subject S is formed with
the lens 3 to detect the formed image with the imaging module 6. It
may be applied to such a configuration to achieve advantages
similar to those for the solid imaging apparatus 1 according to the
first embodiment.
[0104] While the configuration according to the first embodiment is
described as the one example in which, in the wavelength
transmission filter array 5, wavelength transmission filters in
which transmission wavelength bandwidths continuously change are
arranged in the X direction (one direction) on the X-Y plane and
wavelength transmission filters in which transmission wavelength
bandwidths are the same are arranged in the Y direction (the other
direction), it is not limited thereto. The configuration may be
such that the wavelength transmission filters in which the
transmission wavelength bandwidths continuously change are arranged
in the Y direction on the X-Y plane and the wavelength transmission
filters in which the transmission wavelength bandwidths are the
same are arranged in the X direction. In this case, the direction
in which the solid imaging apparatus or the subject is swept is the
Y direction.
[0105] The wavelength transmission filter array may be configured
such that, groups with a combination of multiple wavelength
transmission filters having different transmission wavelength
bandwidths as one set are arranged in a two-dimensional array shape
on the X-Y plane. Like a Bayer filter (configured with four sheets
of B, G1, G2, and R as one set) which is generally used for a
visible sensor, the wavelength transmission filter array may be
configured such that n sheets of different wavelength bandwidths as
one set are two-dimensionally arranged in a mosaic (matrix) shape.
Here, FIG. 12 shows, as one example, the correspondence between a
two-dimensional arrangement diagram of a group in which nine
filters of different transmission wavelength bands are combined as
one set and spectral data.
[0106] While a case of a two-dimensionally arranged rectangular
(generally square) shape is described as one example as shown in
FIG. 4 as a metal pattern layer of a metal thin film which makes up
the resonance layer 22 according to the first embodiment, it is not
limited thereto. Here, FIGS. 13A to 13D are a set of plan views
(X-Y plane views) that illustrates different exemplary patterns of
the resonance layer.
[0107] As shown in FIGS. 13A to 13D, pattern shapes for the metal
pattern layer include a regular circle (circle type), a hexagon, a
rectangle, a double circle, for example. Moreover, the periodic
structure of the metal pattern layer may be in the two-dimensional
direction or in the one-dimensional direction. Furthermore, the
periodic arrangement of the metal pattern layer includes a square
arrangement, a hexagonal arrangement, etc. As described above, the
pattern period (.GAMMA.) determines the transmission center
wavelength .lamda..sub.i and the inter-pattern interval (s) affects
the half-value width, etc., of the transmission wavelength and the
transmittance.
Second Embodiment
[0108] FIG. 14 is an enlarged cross-sectional view (X-Z plane view)
illustrating an exemplary configuration of the imaging module in
the solid imaging apparatus according to a second embodiment.
[0109] As illustrated in FIG. 14, an imaging module 206 which makes
up the solid imaging apparatus according to the second embodiment
has a common configuration with that of the imaging module 6 of the
first embodiment in that the resonance layer (metal pattern layer)
22 which makes up a wavelength transmission filter array layer 207
has a pattern period (.GAMMA.) and an inter-pattern interval (s)
that are different depending on the pixel region and has a
configuration which is different therefrom in that a sympathetic
vibration layer 224 and a transmission layer 225 which make up an
interference layer 223 of a wavelength transmission filter array
layer 207 have uniform film thicknesses regardless of the pixel
region. Therefore, the same letters will be given to and
explanations will be omitted for the configuration which is common
to that for the imaging module 6 in the solid imaging apparatus 1
according to the first embodiment.
[0110] As illustrated in FIG. 14, in either one of the pixel region
(1) and the pixel region (2), the interference layer 223 includes
the sympathetic vibration layer 224 of a film thickness d.sub.2 and
the transmission layer 225 of a film thickness d.sub.1.
[0111] Here, for the respective transmission filters, the
transmission center wavelength .lamda..sub.i is determined by the
pattern period (.GAMMA.) of the metal pattern layer. According to
the imaging module 206 according to the present embodiment, the
configuration of the resonance layer (metal pattern layer) 22 which
makes up the wavelength transmission filter array layer 207 is
common to that of the imaging module 6 of the first embodiment, so
that, even when the film thickness configuration of the
interference layer 223 differs, a wavelength transmission filter
array is obtained with the transmission wavelength .lamda..sub.a in
the pixel region (1) and the transmission wavelength .lamda..sub.b
in the pixel region (2).
[0112] On the other hand, when the transmission wavelength changes
to .lamda..sub.c1 to .lamda..sub.c2, for the transmission filter
array, it is preferable to set the film thicknesses d.sub.1 and
d.sub.2 of the sympathetic vibration layer 224 and the transmission
layer 225 to the center wavelength thereof
(.lamda..sub.i'=(.lamda..sub.c1+.lamda..sub.c2)/2) or a value which
is close thereto.
[0113] The solid imaging apparatus according to the second
embodiment includes, in the same manner as the solid imaging
apparatus according to the first embodiment, an imaging module 206
including a wavelength transmission filter array layer 207 in which
multiple wavelength transmission filters with different
transmission wavelength bandwidths are arranged on an X-Y plane, so
that a material of an object to be measured can be discriminated to
identify the discriminated results from wavelength information
obtained by the imaging module 206 and image information thereof
may be obtained.
[0114] According to the second embodiment, the film thicknesses of
the sympathetic vibration layer and the transmission layer are not
changed in correspondence with the pattern of the metal layer,
making it possible to facilitate laminating the wavelength
transmission filter array layer 207 on the semiconductor substrate
19.
Third Embodiment
[0115] FIG. 15 is an enlarged cross-sectional view (an X-Z plane
view) illustrating one example of the configuration of the imaging
module in the solid imaging apparatus according to a third
embodiment.
[0116] As illustrated in FIG. 15, an imaging module 306 which makes
up the solid imaging apparatus according to the third embodiment
has a common configuration with that of the imaging module 6 of the
first embodiment in that a resonance layer (metal pattern layer)
322 which makes up a wavelength transmission filter array layer 307
has a pattern period (.GAMMA.) and an inter-pattern interval (s)
that are different depending on the pixel region and in that a
sympathetic vibration layer 324 and a transmission layer 325 which
make up an interference layer 323 have respectively different film
thicknesses depending on the pixel region, and has a configuration
which is different therefrom in that a semiconductor substrate 319
which makes up an infrared detection device layer 308 is formed in
a lens shape and a wavelength transmission filter array layer 307
is laminated thereon such that it follows the shape thereof.
Therefore, the same letters will be given to and explanations will
be omitted for the configuration which is common to that for the
imaging module 6 in the solid imaging apparatus 1 according to the
first embodiment.
[0117] Here, for the respective transmission filters, the
transmission center wavelength .lamda..sub.i is determined by the
pattern period (.GAMMA.) of the metal pattern layer. According to
the imaging module 306 according to the present embodiment, the
configuration of the resonance layer (metal pattern layer) 322
which makes up the wavelength transmission filter array layer 307
is common to that of the imaging module 6 of the first embodiment,
so that a wavelength transmission filter array is obtained with the
transmission wavelength .lamda..sub.a in the pixel region (1) and
the transmission wavelength .lamda..sub.b in the pixel region
(2).
[0118] For the sympathetic vibration layer 324, in a manner similar
to the first embodiment, to prevent reflection of the transmission
wavelength .lamda..sub.i and increase the transmittance, with the
reflectance of the material thereof being set to n.sub.d1, the film
thickness d.sub.1 is set such that
d.sub.1=.lamda..sub.i/4n.sub.d1.
[0119] For the transmission layer 325, in a manner similar to the
first embodiment, with the reflectance of the material thereof
being set to n.sub.d2, the film thickness is d.sub.2 set such that
d.sub.2=.lamda..sub.i/2n.sub.d2. The film thickness of the
transmission layer 325 is set to be a 1/2 wavelength of the optical
film thickness to cause sympathetic vibration within the thin film
of the transmission layer 325 and increase the transmittance.
[0120] According to the solid imaging apparatus of the third
embodiment, in a manner similar to that of the solid imaging
apparatus of the first embodiment, a material of an object to be
measured can be discriminated to identify the discriminated results
from wavelength information obtained by the imaging module 306 and
image information thereof may be obtained.
[0121] The solid imaging apparatus of the third embodiment is
configured such that the semiconductor substrate 319 which makes up
the imaging module 306 is processed in a lens shape and the
wavelength transmission filter array layer 307 is laminated
thereon. With such a configuration, the imaging module 306 makes it
possible to effectively collect light with the light detector 10
and improve the light detection efficiency.
Fourth Embodiment
[0122] FIG. 16 is an enlarged cross-sectional view (an X-Z plane
view) illustrating one example of the configuration of the imaging
module in the solid imaging apparatus according to a fourth
embodiment.
[0123] As illustrated in FIG. 16, an imaging module 406 which makes
up the solid imaging apparatus according to the fourth embodiment
has a common configuration with that of the imaging module 6 of the
first embodiment in that the resonance layer (metal pattern layer)
22 which makes up a wavelength transmission filter array layer 407
has a pattern period (.GAMMA.) and an inter-pattern interval (s)
that are different depending on the pixel region and in that the
sympathetic vibration layer 24 and the transmission layer 25 which
make up the interference layer 23 have respectively different film
thicknesses depending on the pixel region, and has a configuration
which is different therefrom in that a wavelength transmission
filter array layer 407 is formed on a support layer 409 and
infrared light is irradiated from the support substrate 416 side.
Therefore, the same letters will be given to and explanations will
be omitted for the configuration which is common to that for the
imaging module 6 in the solid imaging apparatus 1 according to the
first embodiment.
[0124] As a material for the support substrate 416 which makes up
the support layer 409, it is preferable to use a material with the
transmittance in a desired infrared region that is sufficiently
high, such as silicon (Si), germanium (Ge), etc., for example. This
makes it possible to effectively transmit light to the light
detector 10.
[0125] Here, for the respective transmission filters, the
transmission center wavelength .lamda..sub.i is determined by the
pattern period (.GAMMA.) of the metal pattern layer. According to
the imaging module 406 according to the present embodiment, the
configuration of the resonance layer (metal pattern layer) 22 which
makes up the wavelength transmission filter array layer 407 is
common to that of the imaging module 6 of the first embodiment, so
that a wavelength transmission filter array is obtained with the
transmission wavelength .lamda..sub.a in the pixel region (1) and
the transmission wavelength .lamda..sub.b in the pixel region
(2).
[0126] In a manner similar to the first embodiment, to prevent
reflection of the transmission wavelength .lamda..sub.i and
increase the transmittance, with the reflectance of the material
thereof being set to n.sub.d1, the film thickness d.sub.1 of the
sympathetic vibration layer 24 is set such that
d.sub.1=.lamda..sub.i/4n.sub.d1.
[0127] In a manner similar to the first embodiment, with the
reflectance of the material thereof being set to n.sub.d2, the film
thickness d.sub.2 of the transmission layer 25 is set such that the
film thickness d.sub.2=.lamda..sub.i/2n.sub.d2. The film thickness
is set to be a 1/2 wavelength of the optical film thickness to
cause sympathetic vibration within the thin film of the
transmission layer 25 and increase the transmittance.
[0128] When the transmission wavelength changes to .lamda..sub.c1
to .lamda..sub.c2, for the transmission filter array, it is
preferable to set the film thicknesses d.sub.1 and d.sub.2 of the
sympathetic vibration layer 24 and the transmission layer 25 to the
center wavelength thereof
(.lamda..sub.i'=(.lamda..sub.c1+.lamda..sub.c2)/2) or a value which
is close thereto.
[0129] According to the solid imaging apparatus of the fourth
embodiment, in a manner similar to that of the solid imaging
apparatus of the first embodiment, a material of an object to be
measured can be discriminated to identify the discriminated results
from wavelength information obtained by the imaging module 406 and
image information thereof may be obtained.
[0130] According to the fourth embodiment, formation of the
infrared detection device 4 and formation of the wavelength
transmission filter array layer 407 onto the support substrate 416
may be moved forward in parallel to reduce manufacturing time of
the imaging module 406.
Fifth Embodiment
[0131] FIG. 17 is an enlarged cross-sectional view (X-Z plane view)
illustrating one example of the configuration of the imaging module
in the solid imaging apparatus according to a fifth embodiment.
[0132] As illustrated in FIG. 17, an imaging module 506 which makes
up the solid imaging apparatus according to the fifth embodiment
has a common configuration with that of the imaging module 406 of
the fourth embodiment in that a wavelength transmission filter
array layer 407 is formed on a support layer 409 and infrared light
is irradiated from the support substrate 416 side, and has a
configuration which is different therefrom in that a support layer
409 and the infrared detection device layer 8 are laminated such
that the resonance layer (metal pattern layer) 22 which makes up
the wavelength transmission filter array layer 407 is located on
the infrared detection device layer 8 side. Therefore, the same
letters will be given to and explanations will be omitted for the
configuration which is common to that for the imaging modules 6 and
406 according to the first and fourth embodiments.
[0133] According to the solid imaging apparatus of the fifth
embodiment, in a manner similar to that of the solid imaging
apparatus of the first embodiment, a material of an object to be
measured can be discriminated to identify the discriminated results
from wavelength information obtained by the imaging module 506 and
image information thereof may be obtained.
[0134] According to the fifth embodiment, in a manner similar to
the solid imaging apparatus of the fourth embodiment, formation of
the infrared detection device 4 and formation of the wavelength
transmission filter array layer 407 onto the support substrate 416
may be moved forward in parallel to reduce manufacturing time of
the imaging module 506.
[0135] According to the fifth embodiment, the wavelength
transmission filter array layer 407 may be provided in proximity to
the light detector 10. This makes it possible to reduce the amount
of mixing in of the transmission wavelengths .lamda..sub.a and
.lamda..sub.b 407 that are incident on neighboring cells and
increase the wavelength resolution.
[0136] The configuration of the solid imaging apparatus according
to the first to fifth embodiments is exemplary, so that it is not
limited thereto.
[0137] While a case of using an imaging module in which the
infrared detection device and the wavelength transmission filter
array are integrated is described as an example in the first to
fifth embodiments, the wavelength transmission filter array 5 may
be located in proximity to the infrared detection device 4 between
the lens (image forming optical member) 3 and the infrared
detection device 4. It is preferable to align the wavelength
transmission filter array and the image region of the infrared
detection device to bring them into close contact to use them. Such
a configuration makes it possible to discriminate a material of an
object to be measured S to identify the discriminated results from
wavelength information obtained by the infrared detection device 4
and obtain image information thereof.
[0138] The solid imaging apparatus according to at least one of the
embodiments described above includes the light source 2 which
irradiates an infrared light onto an object to be measured (a
subject); the lens (image-forming optical member) 3; the infrared
detection device 4 in which multiple pixels which are sensitive in
the wavelength bands to be detected are arranged in a
two-dimensional array on an X-Y plane; and a wavelength
transmission filter array 5 in which multiple wavelength
transmission filters having different transmission wavelength
bandwidths of transmission wavelength bands are arranged on an X-Y
plane. The above-described solid imaging apparatus makes it
possible to provide a solid imaging apparatus which is superior in
the material discrimination performance and from which image
information is obtained. Moreover, a material of an object to be
measured can be discriminated to identify the discriminated results
from wavelength information obtained by the infrared detection
device 4 and image information thereof may be obtained.
[0139] While certain embodiments have been described, these
embodiments have been presented by way of example only, and are not
intended to limit the scope of the inventions. Indeed, the novel
embodiments described herein may be embodied in a variety of other
forms; furthermore, various omissions, substitutions, and changes
in the form of the embodiments described herein may be made without
departing from the spirit of the inventions. The accompanying
claims and their equivalents are intended to cover such forms or
modifications as would fall within the scope and spirit of the
inventions.
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