Invisible code reading device with double optical filters
By employing a dual-filter design in the invisible code reading device, the problem of low imaging contrast caused by reflection interference on highly reflective materials is solved, achieving a more efficient reading effect and adapting to different reading scenarios.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- FUJIAN NEWLAND AUTO ID TECH CO LTD
- Filing Date
- 2025-06-09
- Publication Date
- 2026-05-12
AI Technical Summary
Existing invisible code reading devices suffer from reflection interference on highly reflective materials, resulting in low image contrast and difficulty in reading, especially in application scenarios where vertical or mobile reading is the only option, leading to poor imaging performance.
It adopts a dual-filter design, including an illumination filter and a lens filter, which respectively filter out unnecessary illumination light and stray light, ensuring that the image sensor only captures the light band emitted by the stealth code. The filter is isolated by the lens bracket and light-blocking foam to reduce interference.
It effectively eliminates reflective interference, improves the imaging contrast of the invisible code, and enhances reading efficiency and environmental adaptability.
Smart Images
Figure CN224232183U_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of barcode reading, and more specifically to a device for reading invisible barcodes with dual filters. Background Technology
[0002] With the development of anti-counterfeiting code technology, invisible anti-counterfeiting code technology has been widely used in various product manufacturing fields. Invisible codes, also known as invisible barcodes, are printed using invisible printing technology and are unrecognizable to the human eye. They require special reading equipment to image and read. Invisible codes require illumination of a specific wavelength of light for excitation. Due to the principle of photoluminescence, the barcode emits light in a different wavelength than the excitation wavelength, making the barcode identifiable. However, while the excitation light required for invisible codes is relatively strong, the emitted light is very weak. Therefore, although the barcode can be identified after being excited by specific light, the light reflected from the background can also be identified, resulting in a low contrast between the barcode and the background, making reading more difficult.
[0003] Existing stealth code reading devices often incorporate a single filter at the lens end to improve imaging quality. While the lens filter blocks most of the illumination light, and the image sensor receives all the light emitted by the stealth code, it also receives a small portion of the illumination excitation light and other stray light. For the already weak emitted light from the stealth code, this excess light causes significant interference. This is especially problematic for stealth codes on highly reflective materials, where reflections cause interference, requiring constant adjustments to the reading angle to avoid reflective points. In applications where only vertical reading is possible, or in mobile reading scenarios, significant reflections can negatively impact imaging quality and, consequently, reading performance. Summary of the Invention
[0004] Therefore, the technical problem to be solved by the present invention is to provide a stealth code reading device with a filter to address the shortcomings of the prior art. This device not only reads the stealth code but also eliminates reflective interference, improves imaging contrast, and further enhances reading efficiency and environmental suitability.
[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:
[0006] Technical solution
[0007] A stealth code reading device with dual filters includes:
[0008] Housing support;
[0009] A lighting module, which is disposed within the housing support, includes a lighting module and a lighting filter;
[0010] An imaging module, which is disposed within the housing support, includes an image sensor, a lens module, and a lens filter;
[0011] The light emitted by the illumination module corresponds to the excitation band of the stealth code to be identified, and the illumination filter filters out the portion of the light emitted by the illumination module that intersects with the emission band of the stealth code to be identified.
[0012] The lens filter only allows light waves emitted after the stealth code is excited to pass through.
[0013] The lighting module includes a lighting circuit board and a lighting source, wherein the lighting source is disposed on the lighting circuit board and the lighting filter is located directly in front of the lighting source.
[0014] The lighting module also includes lighting light distribution optics.
[0015] The illumination filter also filters out light in the non-stealth code excitation band from the light emitted by the illumination module.
[0016] The imaging module also includes a lens bracket, which fixes the lens module and isolates the illumination filter and the lens filter.
[0017] The lens module is disposed in front of the image sensor, and the lens filter is disposed in front of the lens module or between the lens module and the image sensor.
[0018] The image sensor's photosensitive band and the lens module's light-transmitting band include the invisible code emission light band.
[0019] It also includes a motherboard, on which a decoding module and a processor module are mounted.
[0020] The front end of the outer casing support is provided with a reading window and a protective screen, and the protective screen covers the reading window.
[0021] The area of the lens filter is smaller than that of the illumination filter, and the lens filter is located at the center of the reading window, while the illumination filter is located at the periphery of the reading window.
[0022] This invention discloses a stealth code reading device with dual filters. By setting an illumination filter and a lens filter, the two filters work together to ensure that only the light wavelength emitted after the stealth code is excited is captured by the image sensor. The dual filters effectively eliminate reflective interference and improve the imaging contrast of the stealth code.
[0023] By using a lens bracket and light-blocking foam, the lens module can be fixed, stray light can be blocked, and the two filters can be isolated from each other to reduce interference.
[0024] By setting up lighting distribution optics, we can flexibly meet the lighting needs of different scenarios. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of a hidden code reading device with dual filters according to Embodiment 1 of the present invention;
[0026] Figure 2 This is an exploded view of the structure of a stealth code reading device with dual filters according to Embodiment 1 of the present invention;
[0027] Figure 3 This is a schematic diagram of the illumination filter band of a stealth code reading device with dual filters according to Embodiment 1 of the present invention;
[0028] Figure 4 This is a schematic diagram of the lens filter band of a stealth code reading device with dual filters according to Embodiment 1 of the present invention.
[0029] 1-Outer shell bracket, 11-Protective screen, 2-Illumination module, 21-Illumination module, 22-Illumination filter, 3-Imaging module, 31-Image sensor, 32-Lens module, 33-Lens filter, 34-Lens bracket, 4-Main board, 41-FPC connector, 5-Light blocking foam, 6-Screw, 7-External cable. Detailed Implementation
[0030] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.
[0031] Example 1, such as Figure 1 and Figure 2 As shown, a stealth code reading device with dual filters includes:
[0032] In this embodiment, the outer casing support 1 includes an upper outer casing cover and a lower outer casing body.
[0033] Lighting module 2, which is disposed within the housing support 1, includes lighting module 21 and lighting filter 22.
[0034] The illumination module 2 can be monochromatic or multichromatic. Depending on the type of identifiable barcode, it can be configured to use visible light, invisible light, or a combination of both. In this embodiment, the illumination module 2 emits monochromatic light of a specific wavelength, with the emission band covering all or most of the excitation bands of the identifiable invisible code. The most important excitation band can be defined as the band in which the illumination module 2 illuminates the code sufficiently to excite identifiable light.
[0035] Imaging module 3, which is disposed inside the housing support 1, includes an image sensor 31, a lens module 32, and a lens filter 33;
[0036] The light emitted by the illumination module 21 corresponds to the excitation band of the stealth code to be identified, and the illumination filter 22 filters out the portion of the light emitted by the illumination module 21 that intersects with the emission band of the stealth code to be identified.
[0037] In this embodiment, when the emission band of the illumination module 2 covers all the excitation bands of the stealth code to be identified, and when the emission band of the stealth code is greater than the excitation band, the end point of the transmittance band of the illumination filter 22 is located between the stealth code excitation band interval and the emission band interval, and the starting point is less than or equal to the starting point of the stealth code excitation band interval.
[0038] When the emission band of the illumination module 2 covers all the excitation bands of the stealth code to be identified, and when the emission band of the stealth code is smaller than the excitation band, the starting point of the transmittance band of the illumination filter 22 is located between the excitation band interval and the emission band interval of the stealth code, and the ending point is greater than or equal to the ending point of the excitation band interval of the stealth code.
[0039] The lens filter 33 only allows light waves emitted after the stealth code is excited to pass through.
[0040] The transmission bands of the illumination filter 22 and the lens filter 33 do not overlap.
[0041] In this embodiment, as Figure 3 and Figure 4 As shown, the stealth code is an infrared stealth code. The stealth code excitation band is 760-820nm, and the emission band after excitation is 850-910nm. The peak wavelength of the illumination light of the illumination module 21 is 790nm. The illumination filter 22 has a cutoff of 350-740nm and 830-1100nm, and transmits 740-830nm. The lens filter 33 has a cutoff of 350-840nm and transmits 840-1100nm.
[0042] When the emission band of the stealth code is greater than the excitation band, the starting point of the filtering band of the lens filter 33 is located between the excitation band interval and the emission band interval of the stealth code and is greater than the end point of the transmittance band of the illumination filter 22, and the end point of the filtering band of the imaging filter 33 is greater than the end point of the emission band.
[0043] When the emission band of the stealth code is less than the excitation band, the end point of the filtering band of the lens filter 33 is located between the excitation band interval and the emission band interval of the stealth code and is less than the start point of the transmittance band of the illumination filter 22, and the start point of the filtering band of the imaging filter 33 is less than the start point of the emission band.
[0044] The lighting module 21 includes a lighting circuit board and a lighting source, wherein the lighting source is disposed on the lighting circuit board and the lighting filter 22 is located in front of the lighting module 21.
[0045] The lighting module 2 also includes a lighting light distribution optics device 23.
[0046] In this embodiment, the illumination range of the illumination module 21 is larger than the effective working area of the lens module 22, and all light rays are filtered by the illumination filter 22. The illumination light distribution optics 23 can be in the form of an illumination lens, a reflector, a light guide, etc., and may not be configured if high optical performance requirements are not required. The number of illumination sources is determined by the actual application scenario and the positioning of the reading device.
[0047] The illumination filter 22 also filters out light in the non-stealth code excitation band from the light emitted by the illumination module 2.
[0048] The imaging module 3 further includes a lens bracket 34, which fixes the lens module 32 and isolates the illumination filter 22 and the lens filter 33. In this embodiment, the two filters are isolated by light-blocking foam 5.
[0049] The lens module 32 is disposed at the front end of the image sensor 31, and the lens filter 33 is disposed at the front end of the lens module 32 or between the lens module 32 and the image sensor 31.
[0050] In this embodiment, the lens filter 33 is disposed at the front end of the lens module 32. For improvements to existing devices, since the internal structure does not reserve mounting space or slots for the filter between the lens module 32 and the image sensor 31, and most are integrated packaged products, this can be solved by directly installing the lens filter at the front end of the lens module 32, a simple and low-cost improvement method. For lens modules that consider filtering performance, a filter mounting position is reserved between the lens module and the image sensor; this method offers better concealment and protection.
[0051] The light-sensing band of the image sensor 31 and the light-transmitting band of the lens module 32 include the stealth code emission light band.
[0052] It also includes a motherboard 4, which is equipped with a decoding module and a processor module.
[0053] In this embodiment, the motherboard 4 is connected to the lighting circuit board via an FPC connector 41 and fixed to the lighting circuit board and the housing bracket 1 by screws 6. The motherboard 4 includes a decoding module, a processor module, and other electronic components. The decoding module decodes the barcode image acquired by the imaging module, reconstructs the encoded information, and transmits the information to the processor module. The processor module sends working signals to other modules based on the encoded information fed back by the decoding module and determines and feeds back the reading result.
[0054] In this embodiment, the image sensor 31 is disposed on the lighting circuit board. In another embodiment, the image sensor is disposed on the motherboard 4. The lighting circuit board has an opening in the middle for the incident light from the imaging module 3 to pass through.
[0055] The front end of the outer casing support 1 is provided with a reading window and a protective screen 11, and the protective screen 11 covers the reading window.
[0056] The area of the lens filter 33 is smaller than that of the illumination filter 22, and the lens filter 33 is located at the center of the reading window, while the illumination filter 33 is located outside the reading window.
[0057] The above embodiments are for illustrative purposes only and are not intended to limit the invention. Therefore, all equivalent changes or modifications made to the methods described in accordance with the claims of this patent application are included within the scope of this patent application.
Claims
1. A device for reading invisible codes with dual filters, characterized in that, include: Outer casing support (1); The lighting module (2) is disposed within the housing support (1) and includes a lighting module (21) and a lighting filter (22); Imaging module (3), which is disposed in the housing bracket (1), includes an image sensor (31), a lens module (32), and a lens filter (33); The light band emitted by the illumination module (21) corresponds to the excitation band of the stealth code to be identified, and the illumination filter (22) filters out the light in the light emitted by the illumination module (21) that intersects with the emission band of the stealth code to be identified. The lens filter (33) only allows light waves emitted after the stealth code is excited to pass through.
2. The invisible code reading device with dual filters according to claim 1, characterized in that: The lighting module (21) includes a lighting circuit board and a lighting source, wherein the lighting source is disposed on the lighting circuit board and the lighting filter (22) is located in front of the lighting module (21).
3. The invisible code reading device with dual filters according to claim 2, characterized in that: The lighting module (2) also includes lighting light distribution optics (23).
4. The invisible code reading device with dual filters according to claim 1, characterized in that: The illumination filter (22) also filters out light in the non-stealth code excitation band from the light emitted by the illumination module (2).
5. The invisible code reading device with dual filters according to claim 1, characterized in that: The imaging module (3) further includes a lens bracket (34), which fixes the lens module (32) and isolates the illumination filter (22) and the lens filter (33).
6. The invisible code reading device with dual filters according to claim 1, characterized in that: The lens module (32) is disposed at the front end of the image sensor (31), and the lens filter (33) is disposed at the front end of the lens module (32) or between the lens module (32) and the image sensor (31).
7. The invisible code reading device with dual filters according to claim 1, characterized in that: The light-sensing band of the image sensor (31) and the light-transmitting band of the lens module (32) include the stealth code emission light band.
8. The invisible code reading device with dual filters according to claim 1, characterized in that: It also includes a motherboard (4), on which a decoding module and a processor module are provided.
9. The invisible code reading device with dual filters according to claim 1, characterized in that: The front end of the outer casing support (1) is provided with a reading window and a protective screen (11), and the protective screen (11) covers the reading window.
10. A stealth code reading device with dual filters according to claim 9, characterized in that: The area of the lens filter (33) is smaller than that of the illumination filter (22), and the lens filter (33) is located at the center of the reading window, while the illumination filter (22) is located at the periphery of the reading window.