A device for measuring the length of a file
The non-contact measurement method using infrared parallel light projection-shadow length detection solves the problem of large errors in traditional root canal file length measurement, achieving higher measurement accuracy and precision in root canal treatment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- GUILIN WOODPECKER MEDICAL INSTR CO LTD
- Filing Date
- 2025-07-21
- Publication Date
- 2026-07-21
AI Technical Summary
Traditional methods for measuring root canal file length are prone to large errors and inaccuracies, which can easily lead to inaccuracies in root canal treatment and complications.
A non-contact measurement method using infrared parallel light projection-shadow length detection is adopted. The infrared light emitter and infrared sensor are set in parallel to each other, and the guide cylinder and limiting groove are used to guide and limit the file needle to ensure that the file needle remains stable during the measurement process.
It improves the accuracy of file length measurement, reduces errors, avoids measurement inaccuracies caused by tilting, and ensures the precision of root canal treatment.
Smart Images
Figure CN224535015U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of medical device technology, specifically a device for measuring the length of a file. Background Technology
[0002] Root canal files are key instruments used in dental root canal treatment to clean and shape root canals. Measuring the length of the root canal file is a crucial step in ensuring the success of the treatment. This operation is directly related to the accuracy of root canal cleaning, shaping, and filling, and avoids complications such as residual infection, periapical periodontitis, or instrument breakage due to improper length.
[0003] Measuring the length of the file is a crucial step in its use. The traditional method involves the dentist inserting the file into the root canal until it reaches the bottom, marking the insertion depth with a vernier numeral on the file, and then withdrawing the file and measuring the length from the file tip to the vernier numeral. This length is the working length of the root canal.
[0004] The traditional measurement method involves placing a file on a ruler and then having medical staff visually observe the position of the file tip and the vernier caliper to obtain the result. This method has significant drawbacks, as not only is the accuracy of the visual result poor, but tilting the file during placement can also cause large or incorrect degree errors. Utility Model Content
[0005] The purpose of this invention is to provide a device for measuring the length of a file, which utilizes a non-contact measurement approach of "infrared parallel light projection-shadow length detection" to avoid the operational errors of the traditional "removal measurement" method, thereby solving the technical problems mentioned in the background.
[0006] To achieve the above objectives, this utility model provides the following technical solution:
[0007] A device for measuring the length of a file, comprising:
[0008] An infrared light emitter is horizontally positioned, with an infrared sensor located below it, and a space between the infrared sensor and the infrared light emitter for the file needle to move.
[0009] An infrared signal processor, located on one side of the infrared sensor, is connected to the infrared sensor via wires; the infrared light emitter is also connected to the infrared light controller via wires.
[0010] The infrared signal processor is equipped with a display module, and the infrared light emitter and infrared sensor are both located inside the housing; a front cover and a rear cover are fixedly connected to both ends of the housing, and the front cover has a through hole in the middle for the file needle to pass through.
[0011] A guide cylinder is fixedly connected to the middle of the outer side of the front cover. A limiting groove is provided below the guide cylinder, and the limiting groove is fixedly connected to the front cover.
[0012] As a further technical solution of this utility model, the guide cylinder is positioned corresponding to the through hole of the front cover plate, and the inner diameter of the guide cylinder is the same as the diameter of the through hole.
[0013] As a further technical solution of this utility model, the limiting groove is arc-shaped and its diameter is the same as that of the vernier limiting block, and the outer wall of the vernier limiting block fits against the inner wall of the limiting groove.
[0014] As a further technical solution of this utility model, the infrared signal processor is provided with a battery at one end, which is located inside the outer casing.
[0015] Compared with the prior art, the beneficial effects of this utility model are:
[0016] 1. In this utility model, the infrared light emitter and the infrared sensor are arranged in parallel to each other, thereby ensuring the stability of the infrared light and ensuring the accuracy of the data; there are no obstructions in the space between the infrared light emitter and the infrared sensor, ensuring that the entire surface of the infrared sensor will receive infrared light, further improving the accuracy of the data.
[0017] 2. In this utility model, the guide cylinder can guide and limit the file needle, and the vernier limiting block always moves in contact with the inner wall of the limiting groove. The cooperation between the guide cylinder and the limiting groove can make the file needle move into the space between the infrared light emitter and the infrared sensor and remain stable, preventing the file needle from tilting, thereby ensuring that the shadow of the file needle is the same as the actual length of the file needle. Attached Figure Description
[0018] Figure 1 This is a three-dimensional structural diagram of the present invention.
[0019] Figure 2 This utility model Figure 1 Top view.
[0020] Figure 3 This utility model Figure 2 AA sectional view.
[0021] Figure 4 This utility model Figure 1 A schematic diagram of the internal structure.
[0022] Figure 5 This utility model Figure 4 Side view.
[0023] Figure 6 This utility model Figure 4 A partial structural diagram.
[0024] Figure 7 This utility model Figure 2 A magnified view of a portion of the image.
[0025] In the diagram: 1-file needle, 2-outer shell, 3-front cover, 4-rear cover, 5-infrared signal processor, 6-infrared light controller, 7-infrared light emitter, 8-infrared sensor, 9-wire, 10-carrier frame, 11-connector frame, 12-battery, 13-vernier limit block, 14-guide cylinder, 15-limiting groove. Detailed Implementation
[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0027] Please see Figure 1-7 In this embodiment of the invention, a device for measuring the length of a file includes...
[0028] An infrared light emitter 7 is horizontally positioned, and an infrared sensor 8 is located below the infrared light emitter 7. There is a space between the infrared sensor 8 and the infrared light emitter 7 for the file needle 1 to move.
[0029] The infrared signal processor 5 is located on one side of the infrared sensor 8 and is connected to the infrared sensor 8 via a wire 9; the infrared light emitter 7 is also connected to the infrared light controller 6 via a wire 9.
[0030] The infrared signal processor 5 is equipped with a display module, and the infrared light emitter 7 and the infrared sensor 8 are both located inside the housing 2. The two ends of the housing 2 are respectively fixedly connected to a front cover plate 3 and a rear cover plate 4, wherein the front cover plate 3 has a through hole in the middle for the file needle 1 to pass through.
[0031] A guide cylinder 14 is fixedly connected to the middle of the outer side of the front cover plate 3. A limiting groove 15 is provided below the guide cylinder 14, and the limiting groove 15 is fixedly connected to the front cover plate 3.
[0032] The infrared light emitter 7 is fixedly connected to multiple connecting brackets 11 at both ends, and the other ends of the multiple connecting brackets 11 are fixedly connected to the two ends of the infrared sensor 8. The multiple connecting brackets 11 are all located inside the outer shell 2, and the multiple connecting brackets 11 are fixedly connected to the inner walls of both sides of the outer shell 2.
[0033] The bottom of the infrared light controller 6 is fixedly connected to the top of the support frame 10, and the two sides of the support frame 10 are fixedly connected to the inner wall of the outer shell 2 respectively.
[0034] By adopting the above technical solution, the infrared light emitter 7 and the infrared sensor 8 are arranged in parallel to each other, thereby ensuring the stability of infrared light and ensuring the accuracy of data; there are no obstructions in the space between the infrared light emitter 7 and the infrared sensor 8, ensuring that the entire surface of the infrared sensor 8 will receive infrared light, further improving the accuracy of data.
[0035] In this embodiment, the outer shell 2 is provided with a partition, and the infrared signal processor 5 is located on one side of the partition, while the infrared light controller 6, the infrared light emitter 7 and the infrared sensor 8 are located on the other side of the partition.
[0036] The guide cylinder 14 is positioned corresponding to the through hole of the front cover plate 3, and the inner diameter of the guide cylinder 14 is the same as the diameter of the through hole; the limiting groove 15 is arc-shaped and its diameter is the same as the diameter of the vernier limiting block 13, and the outer wall of the vernier limiting block 13 fits against the inner wall of the limiting groove 15.
[0037] The outer casing 2 has a through slot on the side near the infrared signal processor 5 for the display module of the infrared signal processor 5 to pass through;
[0038] The infrared signal processor 5 is equipped with a battery 12 at one end, which is located inside the housing 2; the infrared signal processor 5, the infrared light controller 6, the infrared light emitter 7 and the infrared sensor 8 are all electrically connected to the battery 12.
[0039] By adopting the above technical solution, the guide cylinder 14 can guide and limit the file needle 1, and the vernier limiting block 13 always moves in contact with the inner wall of the limiting groove 15. The guide cylinder 14 and the limiting groove 15 work together to allow the file needle 1 to move into the space between the infrared light emitter 7 and the infrared sensor 8 and remain stable, preventing the file needle 1 from tilting, thereby ensuring that the shadow of the file needle 1 is the same as the actual length of the file needle 1.
[0040] As a further explanation of the above embodiments:
[0041] 1. System Composition and Workflow
[0042] Infrared light emitter 7:
[0043] An area-array infrared LED (wavelength 850nm or 940nm) is used in conjunction with a collimating lens to generate uniform parallel light covering the entire measurement area. The MCU controls the LED driver circuit via PWM to adjust the emission power to adapt to different ambient light interferences.
[0044] Measurement area:
[0045] The file 1 is inserted vertically into the parallel light area, casting a shadow on the infrared sensor 8 below. The length of the shadow is linearly related to the actual length of the file.
[0046] Infrared receiver module:
[0047] It consists of a linear CMOS sensor (such as the TCD1304DG, with 3648 pixels and an 8μm pixel pitch), where each pixel converts light intensity into a voltage signal. The sensor needs to operate in a constant current bias state to ensure signal stability.
[0048] Infrared signal processor 5:
[0049] Preamplifier: A low-noise operational amplifier (such as OPA2333) is used to perform IV conversion and primary amplification on the weak photocurrent signal;
[0050] Bandpass filter: Filters out ambient light interference (such as 50 / 60Hz power frequency noise), with a passband set to 10kHz-20kHz;
[0051] ADC Conversion: Use a high-precision ADC of 12 bits or more (such as ADS1115) to digitize analog signals with a sampling rate of ≥50kHz to capture rapidly changing shadow edges.
[0052] MCU control module:
[0053] Using an STM32F4 series or FPGA as the main controller, complete the following core tasks:
[0054] Drive the emission module to control the LED pulse frequency (which is offset from the ambient light modulation frequency).
[0055] Acquire ADC data and execute edge detection algorithms;
[0056] Calculate the shadow length and compensate for it.
[0057] It communicates with the display module and controls power management.
[0058] Display module:
[0059] It connects to an LCD or OLED display via an SPI / I2C interface to display measurement results in real time (accuracy up to 0.01mm) and can store historical data.
[0060] 2. Accuracy assurance measures
[0061] Hardware level:
[0062] Employs a high-resolution sensor (pixel pitch ≤10μm);
[0063] Dual-path differential design: one path measures shadows, and the other path references ambient light to eliminate background interference;
[0064] Temperature compensation circuit: Uses temperature sensors such as DS18B20 to correct errors caused by thermal expansion and contraction.
[0065] Software level:
[0066] Sub-pixel edge detection algorithm (accuracy improved by 3-5 times);
[0067] Multi-point calibration: A mapping table is established using objects of standard length to compensate for system nonlinearity errors;
[0068] Dynamic threshold adaptation: Automatically adjusts the threshold according to the ambient light intensity to avoid overexposure or underexposure.
[0069] 3. Battery 12 and Anti-interference Design
[0070] Battery 12 Management:
[0071] An isolated DC-DC converter is used to ensure power supply isolation between analog and digital circuits;
[0072] Key sensors use LDO regulators (such as AMS1117) to reduce ripple interference.
[0073] Anti-interference measures:
[0074] PCB design: Analog and digital sections are separated, signal lines are routed differentially, and critical signals are shielded.
[0075] Digital filtering: Kalman filtering or moving average filtering to smooth measurement results;
[0076] Communication isolation: I2C / SPI interfaces are equipped with optocoupler isolation to prevent external interference from entering the MCU.
[0077] The working principle of this utility model is as follows: the infrared light emitter 7 and the infrared sensor 8 are arranged in parallel to each other, thereby ensuring the stability of the infrared light and ensuring the accuracy of the data; there are no obstructions in the space between the infrared light emitter 7 and the infrared sensor 8, ensuring that the entire surface of the infrared sensor 8 will receive infrared light, further improving the accuracy of the data.
[0078] The guide cylinder 14 can guide and limit the file needle 1. The vernier limit block 13 always moves in contact with the inner wall of the limit groove 15. The guide cylinder 14 and the limit groove 15 work together to allow the file needle 1 to move into the space between the infrared light emitter 7 and the infrared sensor 8 and remain stable, preventing the file needle 1 from tilting, thereby ensuring that the shadow of the file needle 1 is the same as the actual length of the file needle 1.
[0079] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A device for measuring the length of a file, characterized in that: include An infrared light emitter (7) is horizontally positioned. Below the infrared light emitter (7) is an infrared sensor (8), and there is a space between the infrared sensor (8) and the infrared light emitter (7) for the file needle (1) to move. The infrared signal processor (5) is located on one side of the infrared sensor (8) and is connected to the infrared sensor (8) via a wire (9); the infrared light emitter (7) is also connected to the infrared light controller (6) via a wire (9); The infrared signal processor (5) is equipped with a display module, and the infrared light emitter (7) and infrared sensor (8) are both located inside the housing (2); the two ends of the housing (2) are respectively fixedly connected to a front cover (3) and a rear cover (4), wherein the front cover (3) has a through hole in the middle for the file needle (1) to pass through. A guide cylinder (14) is fixedly connected to the middle of the outer side of the front cover (3). A limiting groove (15) is provided below the guide cylinder (14), and the limiting groove (15) is fixedly connected to the front cover (3).
2. The device for measuring the length of a file according to claim 1, characterized in that: The infrared light emitter (7) is fixedly connected to multiple connecting frames (11) at both ends, and the other ends of the multiple connecting frames (11) are fixedly connected to the two ends of the infrared sensor (8).
3. The device for measuring the length of a file according to claim 2, characterized in that: The multiple connecting brackets (11) are located inside the outer shell (2), and the multiple connecting brackets (11) are fixedly connected to the inner walls on both sides of the outer shell (2).
4. The device for measuring the length of a file according to claim 1, characterized in that: The bottom of the infrared light controller (6) is fixedly connected to the top of the support frame (10), and the two sides of the support frame (10) are fixedly connected to the inner wall of the outer shell (2).
5. The device for measuring the length of a file according to claim 1, characterized in that: The outer shell (2) has a partition inside, and the infrared signal processor (5) is located on one side of the partition, while the infrared light controller (6), infrared light emitter (7) and infrared sensor (8) are located on the other side of the partition.
6. The device for measuring the length of a file according to claim 1, characterized in that: The guide cylinder (14) is positioned corresponding to the through hole of the front cover plate (3), and the inner diameter of the guide cylinder (14) is the same as the diameter of the through hole.
7. The device for measuring the length of a file according to claim 1, characterized in that: The limiting groove (15) is arc-shaped and its diameter is the same as that of the vernier limiting block (13). The outer wall of the vernier limiting block (13) is in contact with the inner wall of the limiting groove (15).
8. The device for measuring the length of a file according to claim 1, characterized in that: The outer casing (2) has a through slot on the side near the infrared signal processor (5) for the display module of the infrared signal processor (5) to pass through.
9. The device for measuring the length of a file according to claim 1, characterized in that: The infrared signal processor (5) is equipped with a battery (12) at one end, which is located inside the outer casing (2).
10. The device for measuring the length of a file according to claim 9, characterized in that: The infrared signal processor (5), infrared light controller (6), infrared light emitter (7) and infrared sensor (8) are all electrically connected to the battery (12).