A multi-channel digital adjustable brightness visual inspection constant current light source control circuit

Abstract

The utility model relates to the technical field of light source control, especially a kind of multi-channel digital adjustable luminance visual inspection constant-current light source control circuit, including microprocessor and light source control module, the light source control module is provided with multi-channel, and each the light source control module includes digital potentiometer, constant-current drive chip and light source, the digital potentiometer is respectively connected with the microprocessor and the constant-current drive chip;The constant-current drive chip is respectively connected with the digital potentiometer and the light source.Connecting.The utility model relates to a kind of multi-channel digital adjustable luminance visual inspection constant-current light source control circuit, can provide multi-channel luminance adjustable light source for machine vision detection field, guarantee the accuracy of visual inspection, and control stability, no stroboscopic, low in price.

Description

Technical Field

[0001] This utility model relates to the field of light source control technology, and in particular to a multi-channel digitally adjustable brightness visual detection constant current light source control circuit. Background Technology

[0002] The light source in visual inspection equipment has a crucial impact on inspection results. The brightness of the light source directly affects image clarity and contrast. Sufficiently high brightness allows details of the inspected object to be clearly presented, reducing blur and shadows, thereby improving inspection accuracy. For example, when inspecting tiny parts, a high-brightness light source makes subtle textures and defects readily apparent, preventing missed detections due to insufficient light. The color characteristics of the light source also affect inspection results; different colors of light have different reflection and transmission properties for different materials. For instance, for the inspection of certain colored objects, a specific wavelength of light source can better highlight their color characteristics, facilitating identification and differentiation. For some transparent or translucent objects, a suitable light source can enhance the visibility of their internal structure, helping to detect internal flaws or inhomogeneities.

[0003] Currently, fixed-brightness light sources are mostly used in machine vision inspection applications, which has the following shortcomings in some applications:

[0004] 1. Ambient light affects the detection results;

[0005] 2. It is not possible to use different brightness levels in a single inspection. For example, in the visual inspection of defects in semiconductor manufacturing products, some features that need to be detected are more obvious when the light source is dim, while other features are more obvious when the light source is bright.

[0006] 3. In some inspection processes, such as OCR recognition for laser engraving and QR code reading, different light source brightness is required for more accurate and faster recognition when the depth of the engraving varies. A light source with fixed brightness cannot automatically adjust its brightness to cooperate with machine vision inspection. Utility Model Content

[0007] To address the aforementioned issues, this invention provides a multi-channel digitally adjustable brightness constant current light source control circuit for visual inspection. This circuit provides a multi-channel adjustable brightness light source for the machine vision inspection field, ensuring the accuracy of visual inspection, and offering stable control, flicker-free operation, and low cost.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0009] A multi-channel digitally adjustable brightness visual detection constant current light source control circuit includes a microprocessor and a light source control module. The light source control module has multiple channels, and each light source control module includes a digital potentiometer, a constant current driver chip, and a light source.

[0010] The digital potentiometer is connected to the microprocessor and the constant current drive chip, respectively.

[0011] The constant current drive chip is connected to the digital potentiometer and the light source, respectively.

[0012] Furthermore, the first pin of the digital potentiometer of each of the light source control modules is sequentially electrically connected to the CSn pin of the microprocessor;

[0013] The second pin of the digital potentiometer of each of the aforementioned light source control modules is electrically connected to the SCK pin of the microprocessor;

[0014] The third pin of the digital potentiometer of each of the aforementioned light source control modules is electrically connected to the SI pin of the microprocessor;

[0015] The sixth pin of the digital potentiometer is electrically connected to the third and fourth pins of the constant current drive chip.

[0016] The seventh pin of the digital potentiometer is connected to the VCC of the circuit through the first resistor;

[0017] The eighth pin of the digital potentiometer is connected to the VCC of the circuit.

[0018] Furthermore, the sixth pin of the digital potentiometer is electrically connected to the third pin of the constant current drive chip through the second and third resistors, and the fourth pin of the constant current drive chip is connected to the GND of the circuit through the fourth resistor.

[0019] The third pin of the constant current drive chip is connected in parallel between the second resistor and the third resistor.

[0020] Furthermore, the first pin of the constant current drive chip of each of the light source control modules is sequentially electrically connected to the ON / OFFn pin of the microprocessor;

[0021] The fifth, sixth, and ninth pins of the constant current drive chip are electrically connected to the negative terminal of the light source, and the positive terminal of the light source is connected to the VCC of the light source.

[0022] Furthermore, the first pin of the constant current drive chip is provided with a fifth resistor and a switch indicator light. One end of the fifth resistor is electrically connected to the first pin of the constant current drive chip, and the other end is electrically connected to the positive terminal of the switch indicator light. The negative terminal of the switch indicator light is connected to the GND of the circuit.

[0023] The beneficial effects of this utility model are:

[0024] The microprocessor is connected to the digital potentiometer of the DA converter circuit via a serial communication bus (SCK, SI, CS1). SCK is the clock line of the serial communication bus, SI is the data line, and CS1 is the chip select signal. The microprocessor sends a digital constant current reference to the digital potentiometer based on control signals. The digital potentiometer converts the digital constant current reference into an analog constant current reference voltage, which is then provided to the third pin of the constant current driver chip. The constant current driver chip drives the light source to output a constant current based on the reference voltage. Furthermore, the constant current driver chip controls the output state of the light source through the ON / OFF pin signal of the microprocessor. This microprocessor can control multiple light sources and adjust the brightness of the light source through the digital potentiometer and the constant current driver chip. It can provide multi-channel adjustable brightness light sources for machine vision inspection, ensuring the accuracy of visual inspection, and offering stable, flicker-free, and inexpensive control. Moreover, by inputting control signals to the microprocessor, it can automatically adjust the brightness according to different feature detection requirements, meeting more complex detection needs. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a multi-channel digitally adjustable brightness visual detection constant current light source control circuit according to a preferred embodiment of the present invention.

[0026] In the diagram, 1-microprocessor, 2-digital potentiometer, 3-constant current drive chip, 4-light source, 51-first resistor, 52-second resistor, 53-third resistor, 54-fourth resistor, 55-fifth resistor, 6-switch indicator light. Detailed Implementation

[0027] 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.

[0028] It should be noted that when a component is described as "fixed to" another component, it can be directly on the other component or may have a component in between. When a component is considered "connected to" another component, it can be directly connected to the other component or may have a component in between. When a component is considered "set on" another component, it can be directly set on the other component or may have a component in between. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0030] Please see Figure 1 This utility model discloses a multi-channel digitally adjustable brightness visual detection constant current light source control circuit, comprising a microprocessor 1 and a light source control module 11. The microprocessor 1 may be an 8-bit microprocessor such as MS8051 or a 32-bit microprocessor such as STM32.

[0031] The light source control module 11 has multiple channels, and each light source control module 11 includes a digital potentiometer 2, a constant current drive chip 3, and a light source 4.

[0032] Digital potentiometer 2 is connected to both microprocessor 1 and constant current drive chip 3. The model of digital potentiometer 2 can be Microchip's MCP41010T.

[0033] The constant current driver chip 3 is connected to the digital potentiometer 2 and the light source 4 respectively. The constant current driver chip 3 can be of model HI1244E, and the light source 4 can be an LED light source, a rare gas bulb light source, or other light sources, or it can be a light source composed of multiple LEDs connected in series or in parallel.

[0034] In this embodiment, the first pin of the digital potentiometer 2 of each light source control module 11 is electrically connected to the CSn pin of the microprocessor 1 in sequence.

[0035] The second pin of the digital potentiometer 2 of each light source control module 11 is electrically connected to the SCK pin of the microprocessor 1.

[0036] The third pin of the digital potentiometer 2 of each light source control module 11 is electrically connected to the SI pin of the microprocessor 1.

[0037] The sixth pin of digital potentiometer 2 is electrically connected to the third and fourth pins of constant current drive chip 3;

[0038] The seventh pin of the digital potentiometer 2 is connected to the VCC of the circuit through the first resistor 51. In this embodiment, one end of the first resistor 51 is connected to the VCC power supply of the circuit, and the other end is connected to the seventh pin of the digital potentiometer 2. It is connected in series with the digital potentiometer 2 to form a voltage divider circuit, which is used to limit the maximum voltage of the constant current reference.

[0039] The eighth pin of digital potentiometer 2 is connected to the circuit's VCC.

[0040] The sixth pin of the digital potentiometer 2 is electrically connected to the third pin of the constant current drive chip 3 through the second resistor 52 and the third resistor 53, and the fourth pin of the constant current drive chip 3 is connected to the GND of the circuit through the fourth resistor 54.

[0041] The constant current reference voltage output from pin 6 of digital potentiometer 2 is divided by resistors 52 and 53 and then connected to pin 3 of the constant current driver chip. Resistor 54 is a current sensing resistor used to detect the output current.

[0042] The third pin of the constant current drive chip 3 is connected in parallel between the second resistor 52 and the third resistor 53.

[0043] In this embodiment, the first pin of the constant current drive chip 3 of each light source control module 11 is sequentially electrically connected to the ON / OFFn pin of the microprocessor 1. The microprocessor 1 connects to the first pin of the constant current drive chip 3 via the ON / OFFn signal to control the opening and closing of the light source 4.

[0044] The first pin of the constant current drive chip 3 is equipped with a fifth resistor 55 and a switch indicator light 6. One end of the fifth resistor 55 is electrically connected to the first pin of the constant current drive chip 3, and the other end is electrically connected to the positive terminal of the switch indicator light 6. The negative terminal of the switch indicator light 6 is connected to the GND of the circuit.

[0045] The output status of the light source is indicated by the fifth resistor 55 and the switch indicator light 6. When the ON / OFFn signal of the microprocessor 1 is high, the corresponding switch indicator light 6 lights up, indicating that the corresponding light source 4 is in the on state. When the ON / OFF1 signal of the microprocessor 1 is low, the switch indicator light 6 turns off, indicating that the corresponding light source 4 is in the off state.

[0046] The fifth, sixth and ninth pins of the constant current drive chip 3 are electrically connected to the negative terminal of the light source 4, and the positive terminal of the light source 4 is connected to the VCC of the light source.

[0047] In this embodiment, the microprocessor 1 is connected to the digital potentiometer 2 of the DA conversion circuit via the serial communication bus SCK, SI, and CS1. SCK is the clock line of the serial communication bus, SI is the data line of the serial communication bus, and CS1 is the chip select signal of the serial communication. The microprocessor 1 sends a digital constant current reference to the digital potentiometer 2 according to the control signal. The digital potentiometer 2 converts the digital constant current reference into an analog constant current reference voltage to provide to the third pin of the constant current driver chip 3. The constant current driver chip 3 drives the light source 4 to output a constant current according to the reference voltage, and the constant current driver chip 3 controls the output state of the light source 4 through the signal of the ON / OFFn pin of the microprocessor 1.

[0048] The microprocessor 1 in this embodiment can control the multi-channel light source 4, and simultaneously adjust the brightness of the light source 4 through the digital potentiometer 2 and the constant current drive chip. This provides a multi-channel, adjustable brightness light source for the machine vision inspection field, ensuring the accuracy of visual inspection, and offering stable, flicker-free, and inexpensive control. Furthermore, by inputting control signals to the microprocessor 1, it can automatically adjust the brightness according to different feature detection requirements, meeting more complex detection needs.

[0049] The workflow of this embodiment is as follows:

[0050] Microprocessor 1 sends a digital constant current reference to the corresponding digital potentiometer 2, which converts the digital constant current reference into an analog constant current reference voltage and provides it to the third pin of the corresponding constant current driver chip 3. The constant current driver chip 3 then drives the light source 4 to output a constant current based on the reference voltage. The output state of the light source 4 is controlled by the ON / OFF1 signal of microprocessor 1.

Claims

1. A multi-channel digitally adjustable brightness visual detection constant current light source control circuit, characterized in that, It includes a microprocessor (1) and a light source control module (11), wherein the light source control module (11) is provided with multiple channels, and each of the light source control modules (11) includes a digital potentiometer (2), a constant current drive chip (3), and a light source (4). The digital potentiometer (2) is connected to the microprocessor (1) and the constant current drive chip (3) respectively; The constant current drive chip (3) is connected to the digital potentiometer (2) and the light source (4) respectively.

2. The multi-channel digitally adjustable brightness visual detection constant current light source control circuit according to claim 1, characterized in that: The first pin of the digital potentiometer (2) of each of the light source control modules (11) is electrically connected to the CSn pin of the microprocessor (1) in sequence. The second pin of the digital potentiometer (2) of each of the light source control modules (11) is electrically connected to the SCK pin of the microprocessor (1); The third pin of the digital potentiometer (2) of each of the light source control modules (11) is electrically connected to the SI pin of the microprocessor (1); The sixth pin of the digital potentiometer (2) is electrically connected to the third and fourth pins of the constant current drive chip (3); The seventh pin of the digital potentiometer (2) is connected to the VCC of the circuit through the first resistor (51); The eighth pin of the digital potentiometer (2) is connected to the VCC of the circuit.

3. The multi-channel digitally adjustable brightness visual detection constant current light source control circuit according to claim 2, characterized in that: The sixth pin of the digital potentiometer (2) is electrically connected to the third pin of the constant current drive chip (3) through the second resistor (52) and the third resistor (53), and the fourth pin of the constant current drive chip (3) is connected to the GND of the circuit through the fourth resistor (54). The third pin of the constant current drive chip (3) is connected in parallel between the second resistor (52) and the third resistor (53).

4. The multi-channel digitally adjustable brightness visual detection constant current light source control circuit according to claim 1, characterized in that: The first pin of the constant current drive chip (3) of each of the light source control modules (11) is electrically connected to the ON / OFFn pin of the microprocessor (1) in sequence. The fifth, sixth and ninth pins of the constant current drive chip (3) are electrically connected to the negative electrode of the light source (4), and the positive electrode of the light source (4) is connected to the VCC of the light source.

5. The multi-channel digitally adjustable brightness visual detection constant current light source control circuit according to claim 4, characterized in that: The first pin of the constant current driving chip (3) is provided with a fifth resistor (55) and a switch indicator (6). One end of the fifth resistor (55) is electrically connected to the first pin of the constant current driving chip (3), and the other end is electrically connected to the positive terminal of the switch indicator (6). The negative terminal of the switch indicator (6) is connected to the GND of the circuit.

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