A weak pressure measuring device

Abstract

This utility model discloses a weak pressure measuring device, including a measuring bracket, a photoelastic sensing layer, a black placement box, a light source, a camera, and a computer. The photoelastic sensing layer is composed of two photoelastic material films orthogonally stacked and fixed to the measuring bracket. The black placement box is placed on the photoelastic sensing layer. The light source is positioned directly below the photoelastic sensing layer and is used to emit light onto it. The camera is positioned directly above the photoelastic sensing layer and is used to capture images of the deformation of the photoelastic sensing layer. The camera is connected to the computer via a data cable. By stacking the two photoelastic material films orthogonally along their optical axes to form the sensing layer, the birefringence effect is enhanced, producing clear, high-contrast interference fringes and color changes under weak pressure, greatly improving the measurement sensitivity and visualization effect.

Description

Technical Field

[0001] This utility model relates to a weak pressure measuring device, belonging to the field of pressure testing technology for small objects. Background Technology

[0002] Pressure sensing technology is a core component of industrial automation and precision measurement, and its performance directly affects production efficiency and detection accuracy. In recent years, optical pressure sensors have gradually become a research hotspot due to their advantages such as resistance to electromagnetic interference and corrosion. Among them, sensing schemes based on photoelasticity have shown unique application potential because they directly convert mechanical stress into changes in optical signals.

[0003] Existing literature (CN 110631746 A) discloses a pressure detection component, detection method, and terminal. The pressure detection component includes: a sensitive element, which is a light-transmitting material that can deform under pressure; a light emitter disposed on one side of the sensitive element for projecting polarized light onto the sensitive element; and a detector disposed on the other side of the sensitive element for receiving the light emitted from the sensitive element and determining the pressure applied to the sensitive element based on the parameter information of the received light. This scheme uses polyurethane elastomer as the sensitive element and detects pressure by converting polarized light phase modulation into an electrical signal using a photodiode. However, the photoelastic stripes and color changes of light passing through the sensitive element in this scheme are limited, which is detrimental to subsequent processing and warrants further research and improvement. Utility Model Content

[0004] Based on the above, this utility model provides a weak pressure measuring device to overcome the shortcomings of the prior art.

[0005] The technical solution of this utility model is: a weak pressure measuring device, comprising a measuring bracket, a photoelastic sensing layer, a black placement box, a light source, a camera, and a computer, wherein,

[0006] The photoelastic sensing layer is composed of two photoelastic material films orthogonally stacked and fixed on the measuring bracket. The black placement box is placed on the photoelastic sensing layer. The light source is located directly below the photoelastic sensing layer and is used to emit light onto the photoelastic sensing layer. The camera is located directly above the photoelastic sensing layer and is used to capture images of the deformation of the photoelastic sensing layer. The camera is connected to the computer via a data cable.

[0007] In one example, the light source is provided with a first polarizer, and the camera is provided with a second polarizer, the second polarizer being at a preset angle to the first polarizer.

[0008] In one example, the second polarizer is positioned at a 45-degree angle to the first polarizer.

[0009] In one example, the photoelastic material film is a PET film.

[0010] The beneficial effects of this invention are as follows: By stacking two photoelastic material films orthogonally along their optical axes to form a sensing layer, this invention enhances the birefringence effect, producing clear, high-contrast interference fringes and color changes even under weak pressure, greatly improving measurement sensitivity and visualization. Furthermore, by setting polarizers at the light source and camera respectively, and setting their polarization axes at a 45-degree angle relative to the film's optical axis, the optical path configuration is further optimized, resulting in clearer interference fringes and a more pronounced dynamic response. This device is particularly suitable for non-contact measurement of small objects or biological samples under weak pressure, possessing optical sensing advantages such as resistance to electromagnetic interference and corrosion, and can be widely applied in fields such as biomedicine and precision manufacturing. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the pressure measuring device.

[0012] Explanation of reference numerals in the attached figures:

[0013] 1. Object to be tested, 2. Black placement box, 3. Photoelastic sensing layer (double layer), 4. Measurement bracket, 5. Light source (with polarizer), 6. Camera (with polarizer), 7. Camera bracket, 8. Data cable, 9. Computer. Detailed Implementation

[0014] To make the above-mentioned objectives, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0015] Please see Figure 1This embodiment discloses a weak pressure measuring device, including a measuring bracket 4, a photoelastic sensing layer 3, a black placement box 2, a light source 5, a camera 6, and a computer 9. The photoelastic sensing layer 3 is composed of two PET films orthogonally stacked and fixedly mounted on the measuring bracket 4. The black placement box 2 is provided on the photoelastic sensing layer 3 for placing the object to be measured 1. The light source 5 is located below the photoelastic sensing layer 3, and a first polarizer is provided on the light source 5. The camera 6 is located above the photoelastic sensing layer 3 and is mounted on a camera bracket 7 with the lens pointing vertically downward. A second polarizer is provided on the camera 6, which is set at a 45-degree angle to the first polarizer. The camera 6 is connected to the computer 9 via a data cable 8, and can send the captured images to the computer 9 for analysis and processing.

[0016] During operation, the object to be tested 1 is gently placed in the black placement box 2. Light is emitted from the light source 5 to the photoelastic sensing layer 3. The camera 6 takes a picture of the deformation of the photoelastic sensing layer 3 from above as an image and inputs it into the computer 9 for processing, such as extracting the stripe distribution and converting it into a pressure value. Since this part is common knowledge in the field, it will not be described in detail.

[0017] The following is a control experiment from the early stages of the study:

[0018] 1. Comparative Experiments on Thin Film Structures

[0019] Single-layer film structure: A single-layer PET film was used. It was found that limited stripe or color changes could only be observed under significant deformation conditions (large load). The specific performance was limited by the film thickness: thick films deformed very little, and the optical effect was weak; although thin films deformed more, the cumulative optical path difference was insufficient, and the phenomenon was also not significant.

[0020] Double-layer film structure (randomly stacked): Two layers of PET film are stacked at random angles in a tightly bonded manner. Clearer photoelastic stripes and color variations were observed compared to the single-layer film structure. The stripe morphology and color distribution are dependent on the relative angle of the optical axes of the two films.

[0021] Double-layer film structure (orthogonal optical axes): A double-layer PET film is used, with the optical axes of the two films precisely set to be perpendicular (90 degrees) to each other. The clearest interference fringes with the highest color contrast were observed. This configuration exhibits optimal ease of operation and structural stability under experimental conditions, and the phenomenon can be stably reproduced.

[0022] Based on the above, it can be seen that a single-layer film structure is difficult to meet the requirements of high-sensitivity optical response for weak pressure measurement. A double-layer film structure (with mutually orthogonal optical axes) has the advantages of high-contrast stripes and ease of operation. Therefore, a double-layer orthogonal optical axis PET film structure was selected as the standard sensing layer configuration of this invention.

[0023] 2. Polarizer Angle Configuration Experiment

[0024] Polarizer angle test relative to the thin film optical axis: When the polarization axis of the polarizer / analyzer forms a 45-degree angle with the thin film optical axis, interference fringes and their dynamic response to pressure changes can be clearly observed. At other angle configurations, although clear fringes and changes can still be observed, the initial fringe morphology and color distribution differ. Therefore, a 45-degree angle between the polarizer's polarization axis and the thin film optical axis is selected as the standard optical configuration of this invention.

[0025] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A weak pressure measuring device, characterized in that, It includes a measuring bracket (4), a photoelastic sensing layer (3), a black placement box (2), a light source (5), a camera (6), and a computer (9), among which, The photoelastic sensing layer (3) is composed of two photoelastic material films stacked orthogonally and fixed on the measuring bracket (4). The black placement box (2) is placed on the photoelastic sensing layer (3). The light source (5) is located directly below the photoelastic sensing layer (3). The light source (5) is used to emit light onto the photoelastic sensing layer (3). The camera (6) is located directly above the photoelastic sensing layer (3). The camera (6) is used to capture images of the deformation of the photoelastic sensing layer (3). The camera (6) is connected to the computer (9) via a data cable (8).

2. The weak pressure measuring device according to claim 1, characterized in that, The light source (5) is provided with a first polarizer, and the camera (6) is provided with a second polarizer. The second polarizer is at a preset angle to the first polarizer.

3. The weak pressure measuring device according to claim 2, characterized in that, The second polarizer is set at a 45-degree angle to the first polarizer.

4. The weak pressure measuring device according to claim 1, characterized in that, The photoelastic material film is a PET film.

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