CN217083957U - Chip-scale infrared spectrometer - Google Patents

Abstract

This patent discloses a chip-level infrared spectrometer. Including an inner and outer two-layer encapsulation structure, the inner layer encapsulates the photoelectric conversion detector, spectroscopic device, and detector drive and processing integrated chip for chip-level high-integration packaging, and the outer layer encapsulates the inner layer structure, microlens or lens, micro The lighting is closely combined to achieve the curing of the overall structure. Among them, the spectroscopic device adopts a thin-film narrow-band filter array, and the detection units of the photoelectric conversion detector are designed with a small interval to eliminate the mixed spectrum. The two correspond to each other in space. Different detector units receive signals of different wavelengths to realize the spectrum. Measurement. The advantage of this chip-level spectrometer is that the overall size is not more than 1 cm, and it is compact, stable, and shock-resistant.

Description

Chip-scale infrared spectrometer

technical field

The patent belongs to the technical field of spectral measurement, and relates to a chip-level miniature spectrometer.

Background technique

Spectral detection technology is a technology that analyzes its composition, properties (temperature, surface structure), etc. by measuring the reflection and emission differences (reflection spectral characteristics/emission spectral characteristics) of the target to different wavelengths of light. Spectroscopic instruments use optical principles to non-destructively analyze the structure and composition of substances qualitatively and quantitatively, and are currently one of the most widely used analytical tools in scientific research and industry. In the field of spectral analysis, the spectrum is generally divided into ultraviolet, visible-near infrared, short-wave, mid-wave infrared, thermal infrared and other parts, corresponding to different material characteristics. The spectral characteristics of infrared spectrum are very rich, which can be widely used in the analysis and detection of material composition, type and other properties. With the application of technology, the application field of spectral measurement technology has expanded rapidly, and there are also a large number of application requirements in daily life, such as the popularization of industrial and agricultural production testing, environmental and home intelligence, and daily consumer electronics. There are many application requirements.

Conventional detectors with high spectral resolution are bulky and expensive, and can only be used in laboratories and other occasions. Miniaturized spectral detectors or analyzers can be used in online applications and field applications, and their performance is lower than that of laboratory applications. At present, there are many products, the overall size is more than 10 cm, and there are relatively few products below 10 cm. Spectrometers of this size are generally used in industrial, commercial and other fields, while consumer electronics, smart life, health and environmental protection, daily The popularization of life and sales industry requires the spectral measurement module to be cheaper, smaller in size, and more convenient to use. Designing a spectrometer with a smaller volume has become a rigid requirement.

The realization of miniature sturdy, easy-to-use, and low-cost infrared spectroscopy measurement devices or modules is an important way for spectroscopy technology to enter more scenes and all aspects and fields of daily life, and its technical path must be highly integrated. Mainly the miniaturization of detectors, spectroscopic devices, driving and information processing circuits, optical systems, and chip-level integration and packaging. There have been many developments in related technologies, but miniaturization and even device-level and chip-level spectrometers are still technical problems. At present, infrared spectrometers with a size of centimeters have very few related production processes and products, which cannot meet the requirements for miniaturization of spectrometers in many fields. .

In 2021, Beijing Yuguang Technology Co., Ltd. proposed a method for preparing a spectral chip and a spectral chip, and obtained an invention patent (CN 112510059 B). The manufacturing method includes: providing a transfer member and a semi-finished product of a spectral chip, wherein the transfer member includes a silicon crystal layer and a silicide layer formed on the silicon crystal layer, and the silicon crystal layer has a regular crystal orientation structure; a light-transmitting medium layer is formed on the surface of the semi-finished spectrum chip; the silicide layer of the transfer member is bonded to the light-transmitting medium layer of the semi-finished spectrum chip; The transfer member is coupled to the semi-finished spectrometer chip to form the spectrometer chip with a light modulation structure. In this way, an optical layer structure having a regular crystal orientation structure can be formed on the surface of the spectrum chip prepared by the above-mentioned specific preparation method, and the optical layer structure has the function of modulating the imaging light. The invention is a typical spectrum chip. The filter structure is processed on the surface of the detector to realize spectrum measurement. The limitation lies in the use of silicon material, which can only measure signals in the visible-near-infrared band.

In the field of consumer electronics, industrial and agricultural online detection, facing different detection requirements, spectrometers with more spectral range options are required. For example, the spectral characteristics of short-wave infrared (referring to light in the wavelength range of 950nm-2500nm) are higher than those of the visible and near-infrared band. The features are richer and more identifiable. It is the wavelength range for the analysis and detection of properties such as the composition and type of materials that are more commonly used. The design of chip-level spectrometers in this band is more difficult and costly. There are no related products, and most The existing technology is only limited to the manufacturing method and process of the spectral chip components, and needs to be equipped with auxiliary components such as drivers and optical lenses to be applied. Therefore, a millimeter-scale micro-spectrometer with more complete overall functions is required.

Chip-scale spectrometers with more selectable spectral ranges can only achieve lower-cost mass production possibilities with chip-level integration, and require the integration of auxiliary circuits and optical components to achieve overall functional integrity. This patent utilizes the method of advancing the miniaturization of infrared spectrometers to chip-level integration, and realizes a spectrometer with an overall volume of only 1 cm ³ or less and full functions.

SUMMARY OF THE INVENTION

The purpose of this patent is to realize a chip-level infrared spectrometer, which can realize an infrared spectrometer with an overall size of millimeters and complete functions through chip-level integration, which is used in consumer electronics, smart life, health and environmental protection, daily life, sales industry and other industries low-cost popular application scenarios.

The chip-level infrared spectrometer has a main structure including: a photoelectric conversion detector chip 1, a thin film spectroscopic device 2, a detector driving and processing integrated chip 3, an inner-layer chip packaging structure 4, an inner packaging window 5, a microlens group or The microlens array 6 and the outer packaging structure 7 are characterized in that the photoelectric conversion detector 1 and the spectroscopic device 2 and the detector driving and processing integrated chip 3 are closely combined through the chip-level packaging structure 4, and the measured signal is incident from the inner layer window 5 ; The microlens group or microlens array 6 and the inner layer structure are combined together through the outer packaging structure 7 to form a spectrometer with an overall size of the order of millimeters.

The wavelength range of the spectroscopic device is within the effective range of the detector, using gradient filters, metasurfaces, surface plasmons or spectroscopic films with integrated microcavity technology or integrated narrow-band filters, which can be divided into multiple selectable It is a narrow-band filter unit that transmits signals of different wavelengths, and it matches the size of the detector and corresponds to it one by one. According to the difference of the detector, matching the filter unit of the corresponding wavelength range can realize the spectral measurement of the visible-near infrared band, the short-wave infrared band, the medium-wave infrared band, the long-wave infrared band and the combination of different bands.

There is a small interval between the detection units of the photoelectric conversion detector 1 to eliminate the influence of spectral aliasing or offset at the edge of the narrow-band filter unit included in the thin-film spectroscopic device 2, so that the detector only receives a single wavelength (the effective band of the narrow-band filter). light signal within the pass range).

The convergence, collimation, and shaping modes of the microlens group or microlens array 6 are matched with the spatial distribution of the detector unit, and the target signal is uniformly dispersed to the detection unit, and is vertically irradiated on the surface of the spectroscopic device.

In addition to fixing the optical element, the outer packaging structure 7 also has the function of packaging and fixing the miniature light source or light source group 8. The outer packaging structure (7) is equipped with a miniature light source or light source group 8 at the edge position, and the light-emitting element can be one or a light source group 8. Multiple, miniature light sources or light source groups 8 are LED light emitting diodes, laser diodes, organic LEDs or other miniature light sources and combinations thereof, the encapsulation structure fixes the light emitting device and makes the light converge and irradiate on the target to be measured, the spectral range of the light source and the The chip-level infrared spectrometer is matched to form an integrated miniature active lighting spectrometer. The chip-level spectrometer itself may not contain a light source. After integrating the light source, it can realize spectral measurement indoors, under no-light conditions and under bad lighting conditions, and expand the application adaptability.

The first advantage of the present application is that a chip-level integrated structure of a spectrometer is provided, the structure includes two layers, and the inner layer structure can perform circuit integration and integrated packaging for chips of different materials and functions, so as to realize detector chips and thin-film spectroscopic devices. And the minimization of the auxiliary circuit system, the control of the internal environment, and the controllability of the spectral measurement accuracy are ensured.

The second advantage of the present application is that the spectral range can be flexibly configured through the selection and combination of detector chips and thin-film spectroscopic devices, respectively, to realize spectrometers in the visible-near infrared, short-wave infrared, thermal infrared and other spectral bands.

The third advantage of the present application is that the provided method realizes the integration of the optical element and the lighting element through the outer layer structure, so that the function of the chip-level spectrometer is complete and has the characteristics of an instrument.

The advantages and features of the present application will become apparent from the description of specific implementation cases, and can be realized by the means and combinations particularly pointed out in the claims.

Description of drawings

The above and other objects, features and advantages of the present application will become more apparent from the more detailed description of the present application in conjunction with the accompanying drawings. The accompanying drawings are used to provide a further understanding of the embodiments of the present application, constitute a part of the specification, and are used to explain the present application together with the embodiments of the present application, and do not constitute a limitation to the present application.

FIG. 1 is a schematic side view of a cross-sectional structure of a chip-scale spectrometer.

Fig. 2 is the front view structure schematic diagram of chip-level spectrometer;

In the picture:

1 photoelectric conversion detector chip;

2 splitting devices;

3 Detector driver and processing integrated chip;

4 inner-layer chip-scale packaging structure;

5 inner package window;

6 microlens groups or microlens arrays;

7 Outer packaging structure;

8 miniature light sources or groups of light sources.

FIG. 3 is a schematic diagram of the layout matching of the detection unit and the filter array of the chip-level spectrometer in the short-wave infrared band.

FIG. 4 is a schematic diagram of the three-layer structure and spatial correspondence of a chip-level spectrometer in the visible and near-infrared band.

FIG. 5 is a schematic diagram of the spatial correspondence between a filter unit and a detector of a chip-level spectrometer in the visible and near-infrared band.

FIG. 6 is a schematic diagram of the corresponding relationship between the filter unit and the detector of the chip-level spectrometer in the thermal infrared band.

Detailed ways

Hereinafter, exemplary embodiments according to the present application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application, and it should be understood that the present application is not limited by the example embodiments described herein.

Chip-level infrared spectrometers are based on practical design concepts, miniaturization concepts, and market goals for mobile terminal applications. Considering cost optimization, they can form different types of micro-devices with various spectral ranges and spectral resolutions.

Example 1: Short-wave infrared chip-scale spectrometer

The short-wave infrared chip-level spectrometer uses an InGaAs detector chip to detect spectral signals. The overall structure is shown in Figure 1 (without integrated light-emitting elements). The size of the detection unit (pixel) of the detector is 25μm*25μm, 128 detection units are arranged in a linear array; the matching driving and signal processing circuits are implemented by silicon-based integrated circuits; the optical filter is integrated with an integrated microcavity. It has a spectral resolution of 5nm and a total of 124 narrow-band spectral channels. The excess detectors can form dark pixels through the mask to collect dark current or background signals for signal processing and temperature correction. The microlens adopts the form of a cylindrical mirror combined with a mirror microarray to realize the dispersion of incident light signals onto the green light sheet on the surface of the linear array detector.

Figure 3 is an example of the layout of the mutual matching relationship between the array of detection units (solid line box) and the integrated filter structure (dotted line box) array. There is a 10μm interval between the pixels, which makes the spectrometer in the absence of optical mirrors. It avoids spectral confounding of adjacent band signals and improves the accuracy of spectral measurement.

The design technical indicators are as follows: wavelength range 1050nm ~ 1650nm, spectral resolution 5nm, device size 10mm*10mm*10mm (excluding light source). The integrated microcavity filter used in the spectroscopic device.

Example 2: Chip-scale spectrometer in visible and near-infrared bands

The chip-level infrared spectrometer based on CMOS silicon photodetector has a measurement distance of not more than 1 cm and a spectral measurement range of 650nm-950nm, which is used for spectral measurement and feature identification in the near-infrared band. The overall structure is shown in Figure 1 and Figure 2. The light source adopts four LEDs, which can cover the visible and near-infrared bands after the spectrum is combined. The four LED lights are installed obliquely and fixedly. The light-emitting surface is 0.5 cm away from the optical axis of the detection window. Full-spectrum illumination in the near-infrared band. The photoelectric conversion detector adopts a CMOS silicon-based area array detector, which is a 36*36 small area array, and the size of each detection unit is 10 microns * 10 microns. The overall size of the device including the readout circuit is 0.5mm*0.5mm. The thin film filter adopts a microcavity filter array. The size of the microcavity structure of each microcavity filter is 20 micrometers * 20 micrometers, which can cover 4 detector units. The spectral bandwidth of the filter is 1.5nm, a total of 200 Each band occupies 800 pixels, and the extra pixels are used for temperature and dark current correction of detection data.

Fig. 4 is a side view of the spatial relationship among the photoelectric conversion detector, thin-film narrow-band filter, and microlens array of the visible-near-infrared spectrometer, and Fig. 5 is a top view of the relationship among the three, in which the solid line square represents The detection unit of the photoelectric converter, the circle represents a lens unit of the microlens array, the outer diameter represents the range of light collected by the lens, and the inner diameter represents the maximum range that is projected to the filter and detection unit after being converged and collimated, and the dotted square corresponds to a A structural unit of a microcavity filter, each structural unit of a microcavity filter corresponds to a central wavelength, and only allows optical signals in the wavelength range from (central wavelength -0.7nm) to (central wavelength +0.7nm) to pass through .

Example 3: Chip-level infrared spectrometer in thermal infrared band

The overall structure of the chip-level infrared spectrometer based on the room temperature thermal infrared band detector is shown in Figure 1, without a light source. The detector adopts a double linear thermal infrared detector, the filter element adopts a linear gradient filter, and the corresponding relationship between the detector and the detector is shown in Fig.

Claims (5)

1. A chip-level infrared spectrometer, comprising a photoelectric conversion detector chip (1), a spectroscopic device (2), a detector driving and processing integrated chip (3), an inner-layer chip-level packaging structure (4), and an inner packaging window ( 5), a microlens group or a microlens array (6), and an outer packaging structure (7), characterized in that: The photoelectric conversion detector chip (1), the spectroscopic device (2) and the detector driving and processing integrated chip (3) are tightly combined by the chip-level packaging structure (4), and the measured signal is incident from the inner packaging window (5) , the spectroscopic device transmits light of different wavelengths into different detector units; the outer package structure (7) combines the microlens group or microlens array (6) and the inner layer structure to form a spectrometer with an overall size of the order of millimeters. 2. a kind of chip-level infrared spectrometer according to claim 1, is characterized in that, described spectroscopic device (2) adopts gradient filter, metasurface, surface plasmon or the spectroscopic film of integrated microcavity technology Or integrated narrowband filters. 3. A chip-level infrared spectrometer according to claim 1, characterized in that, between the detection units of the photoelectric conversion detector chip (1), there is a small amount that eliminates aliasing or offset effects of the edge spectrum of the narrow-band filter unit. interval. 4. A chip-level infrared spectrometer according to claim 1, characterized in that the convergence and collimation, shaping mode of the microlens group or microlens array (6) match the spatial distribution of the detector unit , the detector units are distributed in a rectangle or a square or a circle, and a conventional converging lens is used. When a linear array detector is used, a cylindrical mirror is used to uniformly disperse the target signal to the detection unit. 5. A chip-level infrared spectrometer according to claim 1, wherein the outer packaging structure (7) is provided with a miniature light source or a light source group (8) at the edge position, and the miniature light source or The light source group (8) is an LED light-emitting diode and a laser diode.

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