JPH0772010A - Spectral analyzer - Google Patents

Abstract

PURPOSE:To easily obtain a spectroscopic output having necessary space resolutions and wavelength resolutions by using a solid-state image pick-up device having a spectroscopic filter and a diffraction grating arranged. CONSTITUTION:Solid-state image pick-up device 1, a plurality of photodetectors having a spectroscopic filters are used, and, diffraction gratings and the like are arranged in a two-dimensional array and an A/D conversion circuit 2 converts an analog signal from the solid-state image pick-up device 1 into a digital signal to be transferred to a memory circuit 3 and an addition circuit 4. A control circuit 5 performs a control processing based on preset values of space resolutions and wavelength resolving power to set operating conditions of the addition circuit 4, a solid-state image pick-up device drive circuit 6 and an output circuit 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spectroscopic analyzer using a solid-state image sensor, and more particularly to a spectroscopic analyzer capable of setting spatial resolution and wavelength resolution.

[0002]

2. Description of the Related Art Conventionally, many spectroscopic analyzers are composed of a spectroscopic element and a light receiving element. A diffraction grating, a spectral filter, or the like is used for the spectroscopic element, and a single element such as a photodiode or an array or a one-dimensional or two-dimensional solid-state imaging element is used for the light receiving element.

Conventionally, as a spectroscopic analyzer of this type, for example, as disclosed in Japanese Patent Application Laid-Open No. 64-72015,
There is a system in which monitor pixels having different sensitivities are provided in order to expand the dynamism range. Also, JP-A-64-7
As disclosed in Japanese Patent Publication No. 2016, some amplifier circuits have a plurality of amplification degrees and are provided with means for selecting one amplification degree corresponding to each pixel during reading of pixel output. Further, as disclosed in Japanese Patent Laid-Open No. 21225/1990, the incident angle of light on the diffraction grating is set to a black angle on the short wavelength side, thereby changing the utilization efficiency of the light on the long wavelength side and the light on the short wavelength side, thereby making it wide. It seeks to obtain a dynamic range. Further, as disclosed in Japanese Patent Application Laid-Open No. 2-40516, it is attempted to obtain a wide dynamic range with good linearity by selectively taking out outputs of a plurality of solid-state image pickup elements having different sensitivities in accordance with light of each wavelength. There are also things.

FIG. 4 is a block diagram showing an example of a solid-state image sensor used in a conventional spectroscopic analyzer, and FIG. 5 is a block diagram showing an example of a control system of the spectroscopic analyzer.

In FIG. 4, a photodiode 12 photoelectrically converts incident light and further accumulates charges generated by photoelectric conversion. The transfer gate 13 is for taking in the charges generated and accumulated in the photodiode 12 to the transfer register 14. By applying a voltage to the transfer gate 13, charges are transferred from the photodiode 12 to the transfer register 14. The overflow drain 10 is connected to the power supply voltage in order to discharge the charges excessively accumulated in the photodiode 12, and has the lowest potential.

The overflow gate 11 is designed so that its potential becomes lower than the potential of the photodiode 12 when a voltage is applied, and the overflow gate 11 is accumulated in the photodiode 12 before the integration when the integration of the solid-state image pickup device is started. It has a function of an integral clear gate for discharging unnecessary charges to the overflow drain 10. The capacitor 16 converts the charge of each pixel sequentially transferred from the transfer register 14 into a voltage, and the capacitor 16 is charged to the power supply voltage by the reset FET 15 prior to the transfer of the charge. The solid-state image sensor output buffer 17 is
The voltage in the capacitor 16 is output to the outside as a signal OS. The aluminum film 18 is for shielding the photodiode 12 from light. In FIG. 4, the rightmost pixel is numbered 1st pixel, and the leftmost pixel is numbered 2nd pixel.

Here, the 1st pixel is so constructed that it shields 15/16 of the area and has a photosensitivity of 1/16 that of a normal pixel in which the photodiode 12 is not shielded. Two
Similarly, the No. pixel has a sensitivity of 1/8 of that of a normal pixel, the No. 3 pixel has a sensitivity of 1/4, the No. 4 pixel has a sensitivity of 1/2, and the No. 5 pixel is a normal pixel not shielded from light. Has become.

In FIG. 5, the microcomputer 24
Controls the solid-state image sensor 19 and processes the output data. The basic clock generation unit 23 includes the solid-state image sensor 1
A basic clock for generating pulse signals for driving 9 and processing the output signal, and a basic clock for the A / D converter 22 are generated. The pulse generator 21 is composed of a logic circuit such as a flip-flop, a NAND gate, and a NOR gate, and drives the solid-state image pickup device 19, performs integration control, and performs an output process on the analog processing circuit 2.
Each pulse signal for controlling 0 is generated.

[0009]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In Japanese Patent Publication No. 72015, a method for expanding a dynamic range is described. For that reason, a monitor pixel whose sensitivity is changed in order to obtain a certain output according to integration times of a plurality of stages is normally used for measurement. There are problems that an optical system that is necessary around a pixel and that has a wide imaging range is necessary, and that an aluminum film must be accurately formed on a monitor photodiode in the production of a solid-state imaging device.

Further, in JP-A-64-72016,
Since the amplification stage corresponding to each pixel is selected during the reading of the pixel output, there is a problem that it is not possible to correct the sensitivity variation between pixels, which is necessary for highly accurate measurement. Further, in JP-A-2-21225, since the incident angle of light on the diffraction grating is set to the black angle on the short wavelength side, the sensitivity on the long wavelength side is lowered, the dynamic range is narrowed, and the S / N ratio is reduced. There is a problem of causing a decline.

Further, in Japanese Patent Laid-Open No. 2-40516, a plurality of solid-state image pickup devices having different sensitivities are required in order to expand a dynamic range, and the plurality of solid-state image pickup devices are provided with a light receiving surface with an accuracy of a pixel size or more. There is a problem that it must be placed in.

The object of the present invention is to solve these problems,
It is set in the control circuit after converting the analog signal into a digital signal using the solid-state image sensor consisting of only the photodiodes with normal sensitivity and performing the calculation with the sensitivity correction data stored in the memory circuit in advance. It is an object of the present invention to provide a spectroscopic analysis device capable of easily obtaining a spectral output having a required spatial resolution and wavelength resolution by performing the above arithmetic processing.

[0013]

The structure of a spectroscopic analysis device of the present invention is a solid-state image pickup device having a spectroscopic optical system for dispersing incident light on the front surface, and an analog signal output from the solid-state image pickup device is converted into a digital signal. An A / D conversion circuit for conversion, a memory circuit storing the sensitivity correction data created in advance by storing the digital signal, sensitivity correction data of the memory circuit or intermediate calculation data, and output data of the A / D conversion circuit. An adder circuit for performing image calculation by adding, an operation procedure of the adder circuit, a control circuit for performing condition setting and output control of the solid-state image sensor, a control signal required for the operation of the solid-state image sensor by the control circuit, Image sensor drive circuit for outputting a control timing signal to the A / D conversion circuit and the memory circuit, and an output circuit for outputting the operation output of the adder circuit to an external circuit Characterized in that it comprises a.

[0014]

1 is a block diagram showing the configuration of an embodiment of the present invention. The solid-state image sensor 1 shown in FIG. 1 uses a solid-state image sensor in which a spectroscopic element such as a spectral filter or a diffraction grating and a plurality of light receiving elements having an optical system arranged on the front surface are arranged in a two-dimensional array. The A / D conversion circuit 2 converts an analog signal from the solid-state image sensor 1 into a digital signal and transfers it to the memory circuit 3 and the addition circuit 4. The memory circuit 3 measures the sensitivities of a plurality of light-receiving elements that form the solid-state image sensor 1 using a standard light source, and the sensitivity correction data created in advance and the digital data transferred from the A / D conversion circuit 2. The signal data and the mid-calculation data transferred from the adder circuit 4 are recorded, and the adder circuit 4 records the data in response to the write request and outputs the data in response to the read request.

The adder circuit 4 performs the arithmetic processing of the digital signal data from the A / D conversion circuit 2 and the sensitivity correction data or the mid-calculation data stored in the memory circuit 3 by the control circuit 5. Then, the calculation result is output to the memory circuit 3 or the output circuit 7. The control circuit 5 performs the calculation procedure of the adder circuit 4, the condition setting of the solid-state image sensor drive circuit 6, and the output control of the output circuit 7. The solid-state image sensor drive circuit 6 provides a control signal necessary for the operation of the solid-state image sensor 1, a timing signal for starting a conversion start signal to the A / D conversion circuit 2, and a control signal to the memory circuit 3. It is generated and output based on the setting of the control circuit 5. The output circuit 7 outputs the arithmetic data from the adder circuit 4 to the control circuit 5.
The signals are associated with each other based on the setting of, and the signal is matched with the signal level with the external circuit before being output.

Next, the spectral output having the spatial resolution and wavelength resolution necessary for the spectroscopic analysis measurement output in the embodiment of FIG. 1 will be described. FIG. 2 is an example of a conceptual diagram of data processing of this embodiment. Further, FIG. 3 is an example of an explanatory diagram of data processing in FIG.

In FIG. 2, the X-axis is the wavelength resolution and the Y-axis is
The spatial resolutions are shown on the A and Z axes, 8a indicates that each of the three resolutions is dense, 8b indicates that only the X axis has a coarse resolution and Y and Z axes indicate a fine resolution, and 8c indicates that the X and Y axes have a coarse resolution. Shows the case where only the Z axis is dense.

The processed data 8a shown in FIG.
3 shows a state in which the analog signal from 1 is converted into a digital signal by the A / D conversion circuit 2 and the sensitivity is corrected, and corresponds to the processing 9a up to A / D conversion in FIG. Next, the adder circuit 4 repeats the process for the number of times set by the control circuit 5 to obtain data having a required wavelength resolution. This state is shown in Figure 2.
3 corresponds to the processing data 8b of FIG. 3, the actual processing corresponds to the processing 9b of spectrum information compression in FIG. 3, and the mid-operation data processed by the adder circuit 4 is stored in the memory circuit 3 and set by the control circuit 5. After performing only the calculation, divide by the set number of times.

Since the spatial information is two-dimensional, that is, the Y-axis and the Z-axis, the same processing as described above is repeated twice to obtain data having the required spatial resolution. The processing data 8c in FIG. 2 and the spatial information compression processing 9c in FIG. 3 correspond to the processing in the Y-axis direction, and the processing data 8d in FIG. 2 and the spatial information compression processing 9d in FIG. Corresponds to the processing. By performing the above processing, it is possible to finally obtain data having the required wavelength resolution and spatial resolution.

Although the present embodiment is for spectroscopic analysis, it can be used for other purposes. Further, in the present embodiment, the spectroscopic optical system (not shown) may be a lens, a reflecting mirror, or another optical system as an optical system, or may be a combination thereof. The spectroscopic system may be a transmission type interference filter, a reflection type interference filter, a transmission type diffraction grating, a reflection type diffraction grating, or another spectroscopic element.

Further, although the solid-state image pickup element is used as the light receiving element in this embodiment, other photoelectric conversion elements may be used. Further, in the present embodiment, the spectroscopic optical system, the solid-state image sensor, and the electronic circuit including the A / D conversion circuit are included, but other optical systems, circuits, and mechanisms may be added.

[0022]

As described above, the spectroscopic analyzer according to the present invention converts an analog signal into a digital signal by using a solid-state image pickup device composed only of a photodiode having a normal sensitivity, and stores it in advance in a memory circuit. By performing the arithmetic processing set by the control circuit after performing the arithmetic operation with the sensitivity correction data stored in (1), it is possible to easily obtain the spectral output having the required spatial resolution and wavelength resolution.

[Brief description of drawings]

FIG. 1 is a block diagram of a spectroscopic analyzer according to an embodiment of the present invention.

FIG. 2 is a three-dimensional coordinate diagram for explaining the concept of data processing of the spectroscopic analyzer of FIG.

3 is an explanatory diagram of data processing of the spectroscopic analyzer of FIG. 1. FIG.

FIG. 4 is a block diagram of an example of a solid-state image sensor used in a conventional spectroscopic analysis device.

FIG. 5 is a block diagram of an example of a control system of a conventional spectroscopic analyzer.

[Explanation of symbols]

 1 Solid-state image sensor 2 A / D conversion circuit 3 Memory circuit 4 Adder circuit 5 Control circuit 6 Solid-state image sensor drive circuit 7 Output circuit 8a-8d Process data 9a-9d process 10 Overflow drain 11 Overflow gate 12 Photodiode 13 Transfer gate 14 Transfer register 15 Reset FET 16 Capacitance 17 Output buffer 18 Aluminum film 20 Analog processing circuit 21 Pulse generation circuit 22 A / D converter 23 Basic block generation unit 24 Microcomputer

Claims (1)

[Claims] 1. A solid-state image sensor having a spectroscopic optical system for dispersing incident light on a front surface thereof, and an A / D conversion circuit for converting an analog signal output from the solid-state image sensor into a digital signal.
A memory circuit that stores the digital signal and previously stored sensitivity correction data, and an adder circuit that adds the sensitivity correction data of this memory circuit or intermediate calculation data to the output data of the A / D conversion circuit to perform image calculation And a calculation circuit of the adder circuit, a control circuit for performing condition setting and output control of the solid-state image sensor, a control signal required for the operation of the solid-state image sensor by the control circuit, the A / D conversion circuit, and the memory circuit. A spectroscopic analysis apparatus comprising: an image sensor drive circuit that outputs a control timing signal to the output circuit and an output circuit that outputs the arithmetic output of the adder circuit to an external circuit.