A Substance Content Detection Chip and Its Detection Method

Abstract

The present invention discloses a substance content detection chip and its detection method, which includes a substance characteristic peak laser, at least one reference characteristic peak laser, a detector and a processing circuit. The substance characteristic peak laser and at least one reference characteristic peak laser emit laser light into free space and irradiate an object to be measured. The laser light reflected by the object to be measured is received by the detector. The substance characteristic peak laser, at least one reference characteristic peak laser and the detector are respectively connected to the processing circuit and controlled by the processing circuit. The present invention has low cost, good system stability, small volume, low power consumption, without any mechanical device, and can be integrated with intelligent devices to achieve high-precision detection of substances.

Description

Technical Field

[0001] The present invention relates to a detection chip and a detection method thereof, in particular to a substance content detection chip and a detection method thereof, belonging to the technical field of semiconductor chips. Background Art

[0002] Substance detection, especially moisture detection, has important applications in industries such as food, textile, paper, wood, and pharmaceuticals. For example, in the food industry, a certain moisture content can maintain food quality and extend food preservation. For instance, milk powder requires a moisture content of 3.0 - 5.0%. When the moisture content increases, the milk powder is prone to color change and the storage period is reduced. In terms of water content, the water content level of food also affects the flavor, spoilage, and mildew of food. The water content of food has a crucial relationship with many aspects such as the freshness, hardness, fluidity, taste, preservation, and processability of food.

[0003] Common near-infrared moisture detection instruments mainly place a combination of narrowband filters behind a tungsten lamp. By rotating the filter array, light of a specific wavelength is emitted. After passing through optical elements such as lenses and mirrors, the parallel light is reflected onto the measured sample material. Among them, part of the infrared light is absorbed by the sample, and the other part of the infrared light is scattered and gathered into a near-infrared sensor. The internal digital processor of the sensor processes the reference light and measurement light of the optical signal and transmits them to the instrument host. The host displays the moisture content of the measured object through a pre-existing model inside. Such near-infrared moisture detection instruments are large in volume, high in power consumption, and contain mechanical rotating devices, making it difficult to achieve miniaturization, energy conservation, and operation in a vibrating environment. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a substance content detection chip and a detection method thereof, which can achieve high-precision substance detection with a small-sized chip.

[0005] To solve the above technical problem, the technical solution adopted by the present invention is:

[0006] A substance content detection chip includes a substance characteristic peak laser, at least one reference characteristic peak laser, a detector, and a processing circuit. The substance characteristic peak laser and at least one reference characteristic peak laser emit laser into free space and irradiate the object to be measured. The laser reflected by the object to be measured is received by the detector. The substance characteristic peak laser, at least one reference characteristic peak laser, and the detector are respectively connected to the processing circuit and controlled by the processing circuit.

[0007] Furthermore, the laser wavelength of the substance characteristic peak laser corresponds to the absorption characteristic peak of the substance, and the laser wavelength of the reference characteristic peak laser is far from the characteristic absorption peak of the substance.

[0008] Further, the laser wavelength of the substance characteristic peak laser is 1430 - 1520 nm.

[0009] Further, the laser wavelength of the reference characteristic peak laser is 1290 - 1340 nm.

[0010] Further, when the number of the reference characteristic peak lasers exceeds 1, the laser wavelengths between multiple reference characteristic peak lasers are different from each other.

[0011] Further, the processing circuit at least includes functions of digital - to - analog conversion, amplification, and high - frequency clock.

[0012] Further, the substance characteristic peak laser and at least one reference characteristic peak laser sequentially emit laser into free space in chronological order under the control of the processing circuit. After the laser irradiates the object to be measured and is reflected, it is sequentially received by the detector in chronological order.

[0013] Further, a filter film is plated on the detector, and the filter film has a high transmittance only at the wavelengths of the substance characteristic peak laser and at least one reference characteristic peak laser.

[0014] Further, the substance characteristic peak laser, at least one reference characteristic peak laser, the detector, and the processing circuit are integrated on a silicon substrate in a monolithic integration or hybrid integration manner.

[0015] A method for detecting the moisture content of a substance content detection chip includes the following steps:

[0016] Before the test, the substance characteristic peak laser and at least one reference characteristic peak laser emit laser under different voltage drives, and the emission power W1 of the substance characteristic peak laser and the emission power W2 of at least one reference characteristic peak laser are respectively measured.

[0017] During the test, the substance characteristic peak laser and at least one reference characteristic peak laser emit laser into free space in chronological order with the same drive voltage.

[0018] After the laser is reflected by the object to be measured, it is sequentially received by the detector in chronological order. The detector sequentially receives the reflection signal intensity P1 of the substance characteristic peak laser and the reflection signal intensity P2 of at least one reference characteristic peak laser.

[0019] Dividing the reflection signal intensity P1 of the substance characteristic peak laser by the emission power W1 of the substance characteristic peak laser to obtain the reflectivity R1 = P1 / W1 of the object to be measured for the laser emitted by the substance characteristic peak laser.

[0020] Dividing the reflection signal intensity P2 of at least one reference characteristic peak laser by the emission power W2 of at least one reference characteristic peak laser to obtain the reflectivity R2 of the object to be measured for the laser emitted by at least one reference characteristic peak laser, where R2 = P2 / W2;

[0021] If R1 = R2, it is determined that there is no substance in the object to be measured;

[0022] If R1 ≠ R2, it is determined that the object to be measured contains a substance, and the absorbance X of the substance in the object to be measured for the laser is calculated as X = 1 - (1 - P1 / W1) / (1 - P2 / W2), and the substance content of the object to be measured is obtained by means of a look-up table according to the value of X.

[0023] Compared with the prior art, the present invention has the following advantages and effects: The present invention integrates a laser, a detector, and a processing circuit on the same substrate to realize the detection of the substance content. Since a laser is adopted, there is no need for an expensive narrow-band filter, which can effectively reduce the cost; The present invention uses a processing circuit to control the working timing of the laser and the detector, and without any mechanical rotating device, it can accurately identify the wavelength signals at different times, and the system stability is greatly improved; Compared with traditional near-infrared moisture detection equipment, the present invention is small in size, low in power consumption, has no mechanical device, and can be integrated with intelligent devices to realize high-precision detection of substances such as moisture. Description of the Drawings

[0024] Figure 1 is a schematic diagram of a substance content detection chip of the present invention. Detailed Embodiment

[0025] In order to elaborate in detail the technical solutions adopted by the present invention to achieve the predetermined technical purposes, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments, and, without creative efforts, the technical means or technical features in the embodiments of the present invention can be replaced. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0026] For the convenience of understanding, the present invention takes the moisture content as an example of the substance content detection to illustrate the present invention.

[0027] Such as Figure 1As shown in the figure, a substance content detection chip of the present invention includes a substance characteristic peak laser 1, at least one reference characteristic peak laser 2, a detector 3, and a processing circuit 4. The substance characteristic peak laser 1 and at least one reference characteristic peak laser 2 emit laser into free space and irradiate a to-be-detected object 5. The laser reflected by the to-be-detected object 5 is received by the detector 3. The substance characteristic peak laser 1, at least one reference characteristic peak laser 2, and the detector 3 are respectively connected to the processing circuit 4 and controlled by the processing circuit 4.

[0028] The laser wavelength of the substance characteristic peak laser 1 corresponds to the absorption characteristic peak of water, that is to say, water has a strong absorption rate for the laser of this wavelength. The laser wavelength of the reference characteristic peak laser 2 is far from the characteristic absorption peak of water, and the water absorption rate of the laser emitted by the reference characteristic peak laser 2 is very weak or non-absorbent. Thus, for the different lasers emitted by the substance characteristic peak laser 1 and the reference characteristic peak laser 2, the difference in the absorption coefficients of water for these two different lasers is greater than 15 times.

[0029] The laser wavelength of the substance characteristic peak laser 1 is 1430 - 1520 nm.

[0030] The laser wavelength of the reference characteristic peak laser 2 is 1290 - 1340 nm. When the number of the reference characteristic peak lasers 2 exceeds 1, the laser wavelengths among the multiple reference characteristic peak lasers 2 are different from each other.

[0031] The processing circuit 4 at least includes functions of digital-to-analog conversion, amplification, and high-frequency clock. Specifically, the processing circuit 4 uses an ADS1256IDBR chip or a circuit structure of the same form to connect to a host computer to implement corresponding functions. The substance characteristic peak laser 1 and at least one reference characteristic peak laser 2 sequentially emit laser into free space in chronological order under the control of the processing circuit 4. After the laser irradiates the to-be-detected object 5 and is reflected, it is sequentially received by the detector 3 in chronological order.

[0032] A filter film is plated on the detector 3. The filter film has a high transmittance only near the wavelengths of the substance characteristic peak laser 1 and at least one reference characteristic peak laser 2, while the transmittance for light of other wavelengths is less than 1%, effectively avoiding the influence of environmental stray light on the detector background noise.

[0033] The material characteristic peak laser 1, at least one reference characteristic peak laser 2, the detector 3 and the processing circuit 4 are integrated on a silicon substrate in a monolithic integration or hybrid integration manner. The materials for fabricating optoelectronic devices and electrical chips include but are not limited to silicon nitride, silicon, silicon oxide, germanium, indium gallium arsenide, etc. The material characteristic peak laser 1, at least one reference characteristic peak laser 2 and the detector 3 are fabricated using III-V materials, and the processing circuit 4 is fabricated using silicon materials. After being fabricated separately, the material characteristic peak laser 1, at least one reference characteristic peak laser 2 and the detector 3 are integrated on the processing circuit 4 through an advanced packaging method. The advanced packaging method can be direct bonding, flip-chip bonding, etc. After integration, the processing circuit 4 can control the working states of the material characteristic peak laser 1, at least one reference characteristic peak laser 2 and the detector 3.

[0034] A method for detecting the moisture content of a material content detection chip includes the following steps:

[0035] Before testing, the material characteristic peak laser and at least one reference characteristic peak laser emit laser light under different voltage drives, and the emission power W1 of the material characteristic peak laser and the emission power W2 of at least one reference characteristic peak laser are respectively tested.

[0036] During testing, the material characteristic peak laser and at least one reference characteristic peak laser emit laser light into free space in chronological order with the same drive voltage.

[0037] The laser light is reflected by the object to be measured and then sequentially received by the detector in chronological order. The detector sequentially receives the reflection signal intensity P1 of the material characteristic peak laser and the reflection signal intensity P2 of at least one reference characteristic peak laser.

[0038] Specifically, under the drive of the circuit processing chip, the reference characteristic peak laser first emits laser light with a wavelength A between 1290 nm and 1340 nm and an optical emission power of W1. The wavelength emitted by this laser does not correspond to a strong absorption peak of water. The laser light irradiates on the object to be measured, and after being reflected by the object to be measured, it is absorbed by the detector. The detector converts the optical signal into an electrical signal, and after being processed and amplified by the circuit processing chip, it is converted into the reflection signal intensity P1 for output.

[0039] The material characteristic peak laser emits laser light with a wavelength B between 1430 nm and 1520 nm and an optical emission power of W2. The wavelength emitted by this laser corresponds to the absorption peak of water. The laser light irradiates on the object to be measured, and after being absorbed and reflected by the object to be measured, it is absorbed by the detector. The detector converts the optical signal into an electrical signal, and after being processed and amplified by the circuit processing chip, it is converted into the reflection signal intensity P2 for output.

[0040] Divide the reflected signal intensity P1 of the material characteristic peak laser by the emission power W1 of the material characteristic peak laser to obtain the reflectivity R1 of the object to be measured for the laser emitted by the material characteristic peak laser, where R1 = P1 / W1.

[0041] Divide the reflected signal intensity P2 of at least one reference characteristic peak laser by the emission power W2 of at least one reference characteristic peak laser to obtain the reflectivity R2 of the object to be measured for the laser emitted by at least one reference characteristic peak laser, where R2 = P2 / W2.

[0042] If R1 = R2, it is determined that there is no moisture in the object to be measured.

[0043] If R1 ≠ R2, it is determined that the object to be measured contains moisture. To accurately measure the absorbance of moisture in the object, the influence of reflectivity needs to be deducted. The laser emitted by the reference characteristic peak laser has no absorption for moisture and can be used as a reference for measuring the reflectivity of the object. Calculate the absorbance X of moisture in the object to be measured for the laser as X = 1 - (1 - P1 / W1) / (1 - P2 / W2), and obtain the moisture content of the object to be measured by looking up the table according to the value of X.

[0044] The way to obtain the table in the look-up table method is as follows: Measure the absorbance X of moisture in the standard object to be measured with known moisture content for the laser at different moisture contents, and form a corresponding table of the measured absorbance X and the moisture content with a large amount of data.

[0045] To improve the accuracy of moisture content detection, the interference of other substances in the object to be measured can be excluded by increasing the number of lasers.

[0046] In the present invention, the laser, the detector, and the processing circuit are integrated on the same substrate to realize the detection of moisture content. Since a laser is used, there is no need for an expensive narrowband filter, which can effectively reduce the cost; the present invention uses the processing circuit to control the working timing of the laser and the detector, and without any mechanical rotating device, it can accurately identify the wavelength signals at different times, and the system stability is greatly improved; compared with the traditional near-infrared moisture detection equipment, the present invention is small in size, low in power consumption, has no mechanical device, and can be integrated with intelligent devices to realize high-precision detection of moisture.

[0047] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical content disclosed above within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent replacement, and improvement made to the above embodiments according to the technical essence of the present invention within the spirit and principle of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for detecting moisture content based on a substance content detection chip, where the substance content detection chip includes a substance characteristic peak laser, at least one reference characteristic peak laser, a detector, and a processing circuit. The substance characteristic peak laser and at least one reference characteristic peak laser emit laser into free space and irradiate an object to be measured. The laser reflected by the object to be measured is received by the detector. The substance characteristic peak laser, at least one reference characteristic peak laser, and the detector are respectively connected to the processing circuit and controlled by the processing circuit; the laser wavelength of the substance characteristic peak laser is 1430 - 1520 nm; the laser wavelength of the reference characteristic peak laser is 1290 - 1340 nm; Characterized in that It includes the following steps: Before the test, the substance characteristic peak laser and at least one reference characteristic peak laser emit lasers under different voltage drives and respectively test the emission power W1 of the substance characteristic peak laser and the emission power W2 of at least one reference characteristic peak laser; During the test, the substance characteristic peak laser and at least one reference characteristic peak laser emit lasers into free space in chronological order with the same drive voltage; The laser is reflected by the object to be measured and then received by the detector in chronological order. The detector sequentially receives the reflection signal intensity P1 of the substance characteristic peak laser and the reflection signal intensity P2 of at least one reference characteristic peak laser; Divide the reflection signal intensity P1 of the substance characteristic peak laser by the emission power W1 of the substance characteristic peak laser to obtain the reflectivity R1 = P1 / W1 of the object to be measured for the laser emitted by the substance characteristic peak laser; Divide the reflection signal intensity P2 of at least one reference characteristic peak laser by the emission power W2 of at least one reference characteristic peak laser to obtain the reflectivity R2 = P2 / W2 of the object to be measured for the laser emitted by at least one reference characteristic peak laser; If R1 = R2, it is judged that there is no substance in the object to be measured; If R1 ≠ R2, it is judged that the object to be measured contains a substance, and calculate the absorbance X of the substance in the object to be measured for the laser as X = 1 - (1 - P1 / W1) / (1 - P2 / W2), and obtain the substance content of the object to be measured by means of a look-up table according to the value of X.

2. The method for detecting moisture content according to claim 1, characterized in that: The laser wavelength of the substance characteristic peak laser corresponds to the absorption characteristic peak of the substance, and the laser wavelength of the reference characteristic peak laser is far from the characteristic absorption peak of the substance.

3. The method for detecting a substance content according to claim 1, characterized in that: When the number of the reference characteristic peak lasers exceeds 1, the laser wavelengths between the multiple reference characteristic peak lasers are different from each other.

4. The method for detecting moisture content according to claim 1, characterized in that: The processing circuit at least includes functions of digital-to-analog conversion, amplification and high-frequency clock.

5. The method for detecting moisture content according to claim 1, characterized in that: The substance characteristic peak laser and at least one reference characteristic peak laser emit lasers into free space in chronological order under the control of the processing circuit. The laser irradiates the object to be measured and is reflected and then received by the detector in chronological order.

6. The method for detecting moisture content according to claim 1, characterized in that: A filter film is plated on the detector, and the filter film has a high transmittance only at the wavelengths of the substance characteristic peak laser and at least one reference characteristic peak laser.

7. The method for detecting moisture content according to claim 1, characterized in that: The substance characteristic peak laser, at least one reference characteristic peak laser, detector and processing circuit are integrated on a silicon substrate in a monolithic integration or hybrid integration manner.

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