JP2713838B2 - Spectral imaging sensor - Google Patents

Abstract

PURPOSE:To provide a spectroscopic imaging sensor wherein its mechanical strength is high and can be operated simply. CONSTITUTION:The imaging sensor is provided with a spectroscopic filter 12 in which a plurality of predetermined pixels are formed as one group, which corresponds to many groups of pixel arrays arranged repeatedly on a two-dimensional plane and in which group filter parts having arranged minute filter parts 13 having respectively different transmission spectroscopic characteristics with reference to the individual pixels in each group are arranged repeatedly so as to correspond to many groups, with a two-dimensional solid-state image sensing device 5 having many photoelectric conversion elements 7 installed so as to correspond to the individual pixels in a pixel array and with an optical filter plate 9 composed of the aggregate of optical fibers optically connecting the individual minute filter parts 13 to the individual photoelectric conversion elements 7. The imaging sensor is constituted in such a way that an image which is incident from the spectroscopic filter is sensed by the two-dimensional solid-state image-sensing device 5 via the optical fiber plate 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spectral imaging sensor for resolving a subject image at predetermined wavelengths.

[0002]

2. Description of the Related Art In recent years, with the development of a sensor having a high sensitivity and a wide wavelength sensitivity range, and the improvement of optical design technology and the development of a new optical material, a point measurement spectroscopic analysis has been conducted.
Research and development using dimension distribution measurement, a so-called image spectral analysis technique, have become active. Its applications range from large-scale ones such as astronomical observation and remote sensing to small-scale ones such as color measurement or microspectroscopy.

In order to promote these research, development and applications, there has been a demand for the development of a spectral imaging sensor which is structurally stable and can be easily used.

[0004] Conventional spectral imaging sensors include:
For example, several types described below are typically known.

[0005] First, a turret in which a plurality of interference filters each transmitting only light of a specific wavelength are arranged and an image sensor are provided, and the turret is interposed between the subject and the image sensor by mechanically rotating or the like. There is a spectral imaging sensor that uses a turret type spectral filter that replaces the interference filters and captures the subject image for each transmission wavelength band of each filter with an image sensor and processes the video signal. ing.

In addition, the apparatus includes a plurality of half mirrors and interference filters arranged on the main optical axis, and a plurality of image sensors provided to face each of these half mirror surfaces.
There is a spectral imaging sensor that applies a half mirror and an interference filter, each of which captures a subject image for each specific wavelength band passing through the half mirror and the interference filter surface with a specific image sensor. Use cases are known.

Further, a spectral imaging sensor that applies a photoacoustic filter to an image sensor to capture an image of a subject in each of a plurality of wavelength bands, and a spectral image obtained by applying an image plane Fourier spectral imaging method using a liquid crystal polarization interferometer. Are known.

[0008]

However, in the spectral imaging sensor to which the turret type spectral filter is applied, since the turret is mechanically rotated, high-speed imaging cannot be performed. Also, there are problems such as a limited application field, mechanical accuracy and aging, and a large size of the entire device.

In a spectral imaging sensor to which the above-mentioned half mirror and interference filter are applied, since the spectral characteristics fluctuate depending on the adjustment accuracy such as optical axis alignment, such adjustment is complicated, and furthermore, the mechanical accuracy and the aging are not improved. There were problems such as changes and high costs. Further, in a spectral imaging sensor to which a photoacoustic filter is applied, since blurring and fluctuation of the color of a final image caused by imperfections of sound waves in the photoacoustic filter cannot be removed, it is extremely difficult to reach a practical range. Many issues remain to be solved.

Also, in a spectral imaging sensor to which an image plane Fourier spectroscopic imaging method using a liquid crystal polarization interferometer is applied, the same problem as the photoacoustic filter, that is, the color of the final image caused by the instability of the liquid crystal. There is a problem that bleeding and fluctuation of the liquid crystal cannot be removed and a problem that response characteristics of the liquid crystal to a control signal are poor, and there are still many problems to be solved before reaching a practical range.

The present invention has been made in view of such problems of the prior art, and has as its object to provide a spectral imaging sensor having high mechanical strength and easy use.

[0012]

According to the present invention, there is provided a spectral imaging sensor for detecting quasi-monochromatic light having a narrow wavelength width and practically regarded as monochromatic light. A spectral filter in which a large number of groups are repeatedly arranged on a two-dimensional plane, with a group including at least 16 fine interference filters having a transmission spectral characteristic having a total width of 20 nm or less and not overlapping each other;
A two-dimensional solid-state imaging device having a structure in which a large number of photoelectric conversion elements corresponding to the respective interference filters are arranged on a two-dimensional plane, and closely adhered between the spectral filter and the two-dimensional solid-state imaging device, An optical fiber plate formed by integrating a plurality of light guide paths for individually and optically coupling the interference filters and the photoelectric conversion elements, the two-dimensional solid-state imaging device, the spectral filter, and the optical fiber plate And a package having a lead terminal electrically connected to the two-dimensional solid-state imaging device, wherein the at least one light is incident on the spectral filter.
The image information including the spectral information of the six quasi-monochromatic lights and the information of the incident position of each quasi-monochromatic light is two-dimensionally detected.

Further, in a spectral imaging sensor for detecting quasi-monochromatic light having a narrow wavelength width and practically regarded as monochromatic light, at least 16 having different central wavelengths, full width at half maximum of 20 nm or less, and transmission spectral characteristics which do not overlap each other. A spectral filter in which a large number of groups are repeatedly arranged on a two-dimensional plane,
A two-dimensional solid-state imaging device having a plurality of photoelectric conversion elements arranged on a two-dimensional plane, the interference filter and the photoelectric conversion elements being associated with each other, and the spectral filter being in close contact with the photoelectric conversion element, and the spectral filter The two-dimensional solid-state imaging device is in close contact with the opposite side, and an optical fiber plate formed by integrating a plurality of light guide paths individually and optically coupled to the respective interference filters, and the two-dimensional solid-state imaging device A cavity having the spectral filter and the optical fiber plate integrally accommodated therein, and a package having a lead terminal electrically connected to the two-dimensional solid-state imaging device, for light incident on the optical fiber plate, Two-dimensionally detecting image information including spectral information of at least 16 quasi-monochromatic lights and information on the incident position of each quasi-monochromatic light. It has a structure.

[0014]

According to the spectral imaging sensor of the present invention having the above-mentioned structure, the subject image is separated by the predetermined number of minute filter sections divided into the respective groups of the spectral filters, so that the predetermined number of different transmission wavelength bands are provided. , And is split into light in the combined transmission wavelength band corresponding to the number of groups arranged in a large number on a two-dimensional plane. For example, if one group is composed of 16 microfilter sections having different transmission wavelength bands, and a large number of such groups are repeatedly arranged on a two-dimensional plane, light of 16 types of wavelength bands is grouped. Occurs according to the number and arrangement of the filter units. Then, since each light is photoelectrically converted by each photoelectric conversion element of the two-dimensional solid-state imaging device, pixel signals of 16 kinds of wavelength bands are obtained corresponding to the number and arrangement of the groups. Further, since each optical fiber of the optical fiber plate corresponds to each pixel, crosstalk between pixels is small.
In addition, the optical fiber plate, the spectral filter, and the two-dimensional solid-state imaging device have high mechanical strength. Further, since these elements are constantly fixed and have no moving parts, the mechanical strength is high as a whole, and Since no adjustment is required, it can be used easily. Furthermore, since an optical fiber plate, a spectral filter, and a two-dimensional solid-state imaging device can be manufactured finely and with high density, even if each spectral wavelength band in all the wavelength bands to be processed is made finer, the resolution can be increased.
A small-sized spectral imaging sensor can be realized without increasing the size of the device as compared with the function. It can be applied to colorimetry, color reproduction of video equipment, spectral analysis of various chemical and physical phenomena, and other broad technical fields.

[0015]

An embodiment of the present invention will be described below with reference to the drawings. First, as shown in FIG. 1, in the spectral imaging sensor of this embodiment, a spectral mechanism 1 having a spectral function is housed in a cavity 3 of a semiconductor package 2, and the spectral mechanism 1
A predetermined connection terminal group provided on the two-dimensional solid-state imaging device 5 which is a component of the above is electrically connected to a plurality of lead terminals 4 provided on the semiconductor package 2. It has a sealed integrated structure. Then, the spectroscopic mechanism 1 disperses the light hν of the subject image transmitted through the transparent glass plate 6, and the two-dimensional solid-state imaging device 5 photoelectrically converts the light hν and outputs it to a predetermined lead terminal 4.

The spectroscopic mechanism 1 has the structure shown in FIGS. That is, in FIG. 2 showing the vertical cross-sectional structure, the two-dimensional solid-state imaging device 5 corresponds to a two-dimensional pixel array preset on an (x-y) two-dimensional plane.
A large number of photoelectric conversion elements (photodiodes or the like) 7 are arranged in a matrix. Although not shown, each pixel signal generated in these photoelectric conversion elements 7 is output to a predetermined lead terminal 4 based on the control of a scanning readout circuit for signal readout. The circuit and a number of photoelectric conversion elements 7 are formed integrally with the two-dimensional solid-state imaging device 5 by a semiconductor manufacturing technique. Therefore, many photoelectric conversion elements 7 are formed in an arrangement as shown in FIG.

On the end face (light receiving face) of the two-dimensional solid-state imaging device 5 where the photoelectric conversion element 7 is formed, an end face of the optical fiber plate 9 (a light output side) is fixed by a fixing layer 8 made of optical bond or optical grease. End face) is fixed. That is, as shown in FIG. 3B, the optical fiber plate 9 is composed of a set of a large number of optical fibers 10 having fine and uniform optical characteristics, and the side end of each optical fiber 10 is an adhesive material that does not transmit light. The layers 11 are integrally fixed. The optical fibers 10 are arranged so as to face a large number of photoelectric conversion elements 7, and a predetermined number of the optical fibers 10 face each photoelectric conversion element 7 of the two-dimensional solid-state imaging device 5. FIG. 3 shows a structure in which four optical fibers 10 face each photoelectric conversion element 7 as an example. However, this is only an example, and a finer optical fiber may be applied so that a large number of fibers may be opposed to each photoelectric conversion element 7 or each photoelectric conversion element 7
Each optical fiber 10 and the photoelectric conversion element 7 may be associated one-to-one by applying an optical fiber having a diameter facing the light receiving surface of the optical fiber.

A spectral filter 12 is laminated on the end face of the optical fiber plate 9 on the light incident side. The spectral filter 12 is composed of a plurality of fine filter units 13 each having different transmission spectral characteristics, and these fine filter units 13 correspond to the arrangement of the photoelectric conversion elements 7 and the arrangement of the optical fibers 10 of the optical fiber plate 9. They are arranged in a one-to-one correspondence. Further, a predetermined number n of small filter units 13 each having a different spectral characteristic and arranged in a predetermined group are grouped together, and the same group is repeatedly arranged on a (xy) two-dimensional plane. ing. Accordingly, each group has n types of transmission spectral characteristics corresponding to the pixel arrangement, and the spectral filter 12 as a whole has a structure including, for example, m groups having the transmission spectral characteristics. FIG.
(A) illustrates the structure of one group corresponding to the arrangement of the photoelectric conversion elements 7 of the two-dimensional solid-state imaging device 5 and the arrangement of the optical fibers 10 of the optical fiber plate 9. That is, one micro filter unit 13 corresponds to a light incident end face of a predetermined number (four in this embodiment) of optical fibers 10 corresponding to each photoelectric conversion element 7, and in this embodiment, , N = 16 micro filter units 13. Therefore, the light transmitted through each of the micro filter sections 13 passes through the predetermined optical fiber 10 and is received by the predetermined photoelectric conversion element 7.

The spectral filter 12 is formed of, for example, an interference filter or the like. The transmission spectral characteristics of the 16 minute filter portions 13 are obtained by dividing the wavelength range of 400 nm to 700 nm into 20 nm wavelength bands. It is designed to have

As described above, according to this embodiment, two-dimensional imaging can be performed by dispersing light in n wavelength bands, and since there is no mechanically movable part, optical adjustment is not required. There is no problem of change.

Next, another embodiment will be described with reference to FIG.
FIG. 4 is a longitudinal sectional view corresponding to FIG. Figure 1
The difference from the previous embodiment shown in FIG. 3 is that the sub-transmission band cut filter 15 is fixed to the light incident side of the spectral filter 12 via a fixing layer 14 made of an optical bond layer or optical grease. ing. The corresponding structures of the spectral filter 12, the optical fiber plate 9, and the two-dimensional solid-state imaging device 5 are the same as those in the previous embodiment. In this embodiment, the sub-transmission band cut filter 15 removes wavelengths other than the wavelength band to be processed in advance, so that the spectral characteristics can be further improved.

Next, still another embodiment will be described with reference to FIG. FIG. 5 is a longitudinal sectional view corresponding to FIGS. 2 and 4, and the same or corresponding parts are denoted by the same reference numerals. The difference from the two embodiments shown in FIGS. 1 to 4 is that many photoelectric conversion elements 7 of the two-dimensional solid-state imaging device 5 are described.
On the side where is formed, the spectral filter 12 is fixed via a fixing layer 16 made of an optical bond layer or optical grease,
Further, the spectral filter 12 is fixed to the light output end of the optical fiber plate 9. A sub-transmission band cut filter 15 is fixed to the light incident end of the optical fiber plate 9 via an optical bond layer 17. The optical fiber plate 9, the spectral filter 12, and the two-dimensional solid-state imaging device 5
Is the same as that of the previous embodiment. And
First, the sub-transmission band cut filter 15 removes wavelengths other than the wavelength band to be processed of the subject image, passes through the respective optical fibers 10 of the optical filter 9, and passes through the respective fine filter portions of the spectral filter 12 having the predetermined transmission spectral characteristics. The two-dimensional solid-state image pickup device 5 receives the light of each wavelength and receives light of each wavelength to perform photoelectric conversion. This embodiment also has the effect that the mechanical strength is high and it can be used easily.

In the above-described three embodiments, a large number of optical fibers 1 having optical fiber plates 9 arranged in parallel with each other are used.
Although it is configured as a bundle of zeros, if each of the minute filter units 13 of the spectral filter 12 and each of the photoelectric conversion elements 7 of the two-dimensional solid-state imaging device 5 have a relationship associated with a predetermined pixel array, For example, as shown in FIG. 6, the light receiving area of each photoelectric conversion element 7 is made smaller with respect to the light incident area of each minute filter section 13, and the side of each optical fiber 10 facing the minute filter section 13. The optical fiber may have a larger diameter and a smaller diameter on the side facing the photoelectric conversion element 7.

Further, in these embodiments, the pixel array is set in a matrix along the orthogonal coordinates (xy) on a two-dimensional plane, and the photoelectric conversion element 7, the optical fiber 10, and the fine filter are arranged in accordance with the pixel array. Although the unit 13 is made to correspond, the present invention is not limited to the arrangement structure along such rectangular coordinates. That is, the pixel arrangement may be appropriately set as long as the micro filter unit 13, the optical fiber 10, and the photoelectric conversion element 7 correspond to each other according to a predetermined pixel arrangement. For example, when manufacturing an optical fiber plate composed of a number of optical fiber bundles by a well-known optical fiber manufacturing technique, first, one optical fiber is stretched while heating to form a thin line, and then a plurality of bundles are bundled. Similarly, the process of stretching, further bundling a plurality of bundles, and stretching in a similar manner is repeated many times, but after such a manufacturing process, the arrangement of each thin optical fiber finally formed becomes a regular hexagon. It becomes a honeycomb-like array arranged at the vertex position of. Therefore, the pixel array is set so as to apply the conventional optical fiber plate, the shape and the array of the minute filter portion of the spectral filter are set so as to correspond to the array, and each photoelectric element of the two-dimensional solid-state imaging device is set. The shape and arrangement of the light receiving surface of the conversion element may be set.

Further, as in these embodiments, the present invention is not limited to arranging the transmission spectral bands of the minute filter unit for each group filter unit of the spectral filter 12 in order according to the wavelength band. Arbitrary arrangement may be made according to the field of application.

By the way, the spectral imaging sensor of the embodiment described above can be applied to, for example, the following fields, and exhibits excellent effects.

First, if the measurement of a dyed object or a painted surface is performed using this sensor, not only the determination of the coloring material used for the dyed object or the painted surface but also the use of the spectral data of the entire measured surface can be performed. This makes it possible to judge and evaluate the dyeing concentration and dyeing distribution of the dyed product and to judge and evaluate the pigment concentration and the density distribution in the coating film. In addition, since the spectral image sensor of the embodiment is a simple sensor that does not require mechanical scanning, it can be used online. In the field of color technology, 4
5 nm, 10 nm, 2 in the wavelength range of 00 nm to 700 nm
Although the standardization of spectrally processing the light of every 0 nm has been performed, according to the structure of the spectral imaging sensor of the present invention, such a large number of wavelengths of light can be processed simultaneously and easily. The sensor can be easily manufactured. In addition, when applied to microscope spectroscopic image measurement, the number of components contained in the observed image and the spatial distribution of each substance can be estimated by using spectral data for each site,
There is also an advantage that they can be imaged. In particular, since the spectral image sensor of the embodiment is a single sensor made into a module, it has a feature that it can be easily attached to a microscope.

In addition, when used as a sensor for optical CT, which has been actively studied at present, spectral information for each part of the living body can be taken in at the same time, so that substances in the living body can be determined.

In particular, since the spectral image sensor of the embodiment is a modularized one sensor, it has a feature that it can be easily attached as a sensor for optical CT.

[0030]

As described above, according to the present invention, a subject image is divided into a predetermined number of different transmission wavelength bands by a predetermined number of minute filter sections provided in each group filter section of the spectral filter. In addition to splitting the light into light, the light is separated into light in the combined transmission wavelength band of the group filters arranged in a large number on the two-dimensional plane, and the subject image or the light after the separation is transmitted through the optical fiber plate. Has a structure in which photoelectric conversion is performed by each photoelectric conversion element of a two-dimensional solid-state imaging device, so that a simple spectral imaging sensor that has little crosstalk between pixels, has high mechanical strength as a whole, and requires no adjustment is provided. be able to. Further, according to the structure of the present invention, the optical fiber plate, the spectral filter, and the two-dimensional solid-state imaging device can be manufactured finely and at a high density. However, it is possible to realize a small-sized spectral imaging sensor without increasing the size of the device as compared with the function. It can be applied to colorimetry, color reproduction of video equipment, spectral analysis of various chemical and physical phenomena, and other broad technical fields.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an entire structure of an embodiment in an exploded manner.

FIG. 2 is a cross-sectional view illustrating a vertical cross-sectional structure of the spectroscopic mechanism 1 according to one embodiment.

FIG. 3 is an exploded perspective view showing an exploded main part structure of the spectroscopic mechanism 1 of the embodiment.

FIG. 4 is a longitudinal sectional view showing the structure of another embodiment.

FIG. 5 is a longitudinal sectional view showing the structure of still another embodiment.

FIG. 6 is a longitudinal sectional view showing the structure of still another embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Dispersion mechanism, 5 ... Two-dimensional solid-state imaging device, 7 ... Photoelectric conversion element, 8, 14, 16 ... Fixed layer, 9 ... Optical fiber plate, 10 ... Optical fiber, 11 ... Adhesive layer, 12
... Spectral filter, 13 ... Micro filter part.

Claims (3)

(57) [Claims] 1. A spectral imaging sensor for detecting quasi-monochromatic light having a narrow wavelength width and practically regarded as monochromatic light, wherein at least 16 having different central wavelengths, full width at half maximum of 20 nm or less and non-overlapping transmission spectral characteristics.
A plurality of fine interference filters as a group, a spectral filter in which a large number of groups are repeatedly arranged on a two-dimensional plane, and a structure in which a large number of photoelectric conversion elements corresponding to the respective interference filters are arranged on a two-dimensional plane. A two-dimensional solid-state imaging device having a light guide path that is closely adhered between the spectral filter and the two-dimensional solid-state imaging device and optically independently couples each of the interference filters and each of the photoelectric conversion elements. A plurality of integrated optical fiber plates, a cavity for integrally storing the two-dimensional solid-state imaging device, the spectral filter, and the optical fiber plate, and a lead terminal for electrically connecting to the two-dimensional solid-state imaging device Wherein the light incident on the spectral filter is divided into at least 16 quasi-monochromatic lights. A spectral imaging sensor for two-dimensionally detecting image information including information and information on an incident position of each quasi-monochromatic light. 2. A spectral imaging sensor for detecting quasi-monochromatic light having a narrow wavelength width and practically regarded as monochromatic light, wherein at least 16 light-transmitting spectral characteristics having different center wavelengths and a full width at half maximum of 20 nm or less and not overlapping each other.
A plurality of fine interference filters as a group, a spectral filter in which a large number of groups are repeatedly arranged on a two-dimensional plane, and a large number of photoelectric conversion elements arranged on a two-dimensional plane. A two-dimensional solid-state imaging device in which the photoelectric conversion elements are associated with each other and the spectral filter is in close contact with the two-dimensional solid-state imaging device in the spectral filter; An optical fiber plate in which a large number of light guide paths that are independently optically coupled are integrated; a cavity that integrally houses the two-dimensional solid-state imaging device, the spectral filter, and the optical fiber plate; and the two-dimensional solid-state imaging device And a package having a lead terminal electrically connected to the optical fiber plate. A spectral imaging sensor for two-dimensionally detecting image information including at least 16 pieces of quasi-monochromatic light spectral information and information on the incident position of each quasi-monochromatic light. 3. The spectral imaging sensor according to claim 1, wherein a sub-transmission band cut filter is closely attached to a light incident side surface of the spectral filter with an optical bond or optical grease interposed therebetween.