LED driving method and circuit for LCD printer

Abstract

The application discloses an LED driving method of an LCD printer, and comprises the following steps: recording the corresponding relationship between the LED brightness and the current value, and the mapping relationship between the stability of the current value and the printing precision of the LCD printer; judging whether to start the current value monitoring circuit of the LED according to the received data; when the received demand level of the printing precision of the user is greater than a first preset value, starting the current value monitoring circuit of the LED, and sending the real-time signal of the current value to the single-chip microcomputer connected with the manager terminal device; when the received demand level of the printing precision of the user is less than the first preset value, not starting the current value monitoring circuit of the LED; setting a first time period T and counting the current value change in the first time period T; and sending the precision quantization level input by the user and the current value change in the first time period T to the manager terminal device through the single-chip microcomputer.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, and in particular to an LED driving method and circuit for an LCD printer. Background Technology

[0002] Currently, LCD (Liquid Crystal Display) photopolymerization...

[0003] 3D (3D) printers all use a single, centrally driven light source. When printing each layer, the machine needs to activate all the LEDs (Light Emitting Diodes) at high power to cure the resin. Moreover, the light source is the most power-consuming component in an LCD photopolymer 3D printer; poor control of its power consumption often results in significant energy waste. LCD-based 3D printers utilize the principle of liquid resin photopolymerization. Using LCD imaging technology, driven by a computer and display driver circuitry, the computer program first discretizes the 3D model into layers of planar graphics. Then, the display driver circuitry controls the LCD screen, transforming designated areas into transparent regions corresponding to the planar graphics (other areas remain opaque black). This allows ultraviolet light from below the LCD screen to penetrate and illuminate the liquid resin above the transparent areas, causing the resin to solidify. The ultraviolet light source is typically an LED (Light Emitting Diode) as the backlight and is integrated with a control system. Furthermore, the luminous intensity of an LED is almost directly proportional to its current; controlling the LED current controls the backlight brightness. Therefore, driving an LED requires a constant and controllable current. An LED is essentially a diode, and the forward voltage drop (VF) of a diode changes with the current, resulting in a change in the channel voltage. Additionally, the VF voltage varies between LEDs due to differences in the wafer. Therefore, the LED driver circuit must be able to automatically adapt to the channel voltage of the LED strip, changing with the LED's voltage. A controllable constant current is essential.

[0004] Existing photopolymer 3D printers include SLA, DLP, and LCD types. In LCD photopolymer 3D printers, the core operation involves slicing the object to be printed into layers of images using a computer, displaying these layers on an LCD screen, and then curing the resin layers with ultraviolet light. Each cured resin layer is then stacked to form a solid object. High precision is required for the light intensity parameters during the photopolymerization process, as these parameters directly affect the thickness and size of each cured resin layer. Therefore, controlling the light intensity directly impacts the machine's printing accuracy. Generally, LCD photopolymer 3D printers use LED chips as their light source. Due to the photoelectric characteristics of LEDs, the higher the current flowing through the LED within its current limit range, the higher its brightness; that is, the brightness of an LED is directly proportional to the current passing through it.

[0005] Currently, the brightness adjustment of LEDs is not precise enough. Because LEDs cure resin layer by layer using ultraviolet light, each cured resin layer is stacked to form a solid. The brightness parameters during the curing process of each layer are highly critical, directly affecting the thickness and size of each cured resin layer. Therefore, controlling the brightness of the light source directly impacts the printing accuracy of the machine, making improvements in precise brightness adjustment necessary. For example, existing technologies such as CN209738286U use the following method for driving the light source in an LCD photopolymerization 3D printer: the actual feedback value detected by the feedback circuit is compared with the current value set in the processor; the processor then adjusts the Ve value to determine a suitable load current and outputs the load current to resistor R4; finally, the driver circuit precisely adjusts the brightness of the LED beads, thus affecting the printer's printing accuracy. However, this method only controls the brightness of the printer's light source by changing the Ve value and does not monitor the brightness of the LEDs themselves.

[0006] For 3D printing equipment, how to stably drive LEDs and monitor the LED drive current according to the printing accuracy requirements are problems that urgently need to be solved in the current technology. Summary of the Invention

[0007] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention discloses an LED driving method for an LCD printer, the driving method comprising the following steps:

[0008] Step 1: Record in advance the correspondence between LED brightness and current value, as well as the mapping relationship between the stability of current value and the printing accuracy of LCD printer. Then, determine whether to turn on the LED current value monitoring circuit based on the received data. The received data is the quantization level of printing accuracy input by the user.

[0009] Step 2: When the received user's printing accuracy requirement level is greater than the first preset value, the LED current value monitoring circuit is turned on, and a real-time signal of the current value is sent to the microcontroller connected to the administrator terminal device. When the received user's printing accuracy requirement level is less than the first preset value, the LED current value monitoring circuit is not turned on.

[0010] Step 3: The microcontroller uses a timer to capture the changes in the received real-time feedback current value I at preset time intervals Δt. Δt When the change in current value exceeds the stability of the current value corresponding to the received user-inputted printing precision quantization level, a first time period T is set, and the change in current value within the first time period is statistically analyzed. The microcontroller then sends the precision quantization level input by the user and the change in current value within the first time period to the management terminal device.

[0011] Preferably, the current monitoring circuit further converts the collected current value into a digital signal and sends it to the microcontroller via a digital signal processing unit.

[0012] Preferably, the current monitoring circuit further includes acquiring the bias current driving the LED, inputting the bias current from terminal B, and monitoring the real-time current value at terminal A. In the current monitoring circuit, one end of the first resistor and the first capacitor are connected to port B, and the other end is connected to port A. The second resistor and the third resistor are connected in parallel and then connected between port B and port A, and port A is grounded.

[0013] Preferably, the bias current of the driving LED is the current value corresponding to the current mirror of the driving LED current.

[0014] Preferably, the microcontroller uses a timer to capture the changes in the received real-time feedback current value I at preset time intervals Δt. Δt Further, it includes: recording the current value I1 at time t1, and recording the current value I2 at time t2, with the following equation:

[0015] t2 = t1 + Δt;

[0016] and I Δt =I2-I1.

[0017] Preferably, setting a first time period T and statistically analyzing the current value changes within the first time period further includes: T = n × I Δt Record n+1 current values ​​and analyze the changes in the difference between two adjacent current values.

[0018] Preferably, based on the quantization level of printing accuracy mapped to the current value changes within the first time period, the n current value changes I are... Δt The average value of the corresponding quantization level of printing precision is calculated. If the calculated quantization level value is greater than the precision quantization level value entered by the user, the current printing job will not be stopped, and the user will be informed of the printing precision fluctuation of the current printing job.

[0019] Preferably, if the calculated quantization level value is less than the precision quantization level value input by the user, an alarm is sent to the printing equipment administrator.

[0020] Preferably, the administrator terminal device is one or more of the following: mobile phone, smartphone, laptop computer, digital broadcast receiver, PDA, PAD, and desktop computer.

[0021] The present invention also discloses an LED driving circuit for an LCD printer, including the functional modules corresponding to the driving method described above.

[0022] Compared with the prior art, the beneficial effects of this invention are as follows: This invention achieves stable LED driving by mapping the stability of the current value to the printing accuracy of the LCD printer, and then determining whether to activate the LED current value monitoring circuit based on the received data. It also monitors the LED driving current according to the printing accuracy requirements, without the need for an additional brightness detection sensor, thus reducing the complexity of desktop printing equipment. It also eliminates the need for a space-consuming brightness sensor, making it easier to make the 3D printing equipment more compact. Furthermore, there is no existing technical solution for monitoring the LED driving current in LCD printing equipment due to printing accuracy requirements. Attached Figure Description

[0023] The invention will be further understood from the following description taken in conjunction with the accompanying drawings. The components in the drawings are not necessarily drawn to scale, but rather the emphasis is on illustrating the principles of the embodiments. In the drawings, the same reference numerals designate corresponding parts in different views.

[0024] Figure 1 This is a structural diagram of an LED driving method and circuit for an LCD printer according to the present invention;

[0025] Figure 2 This is a schematic diagram of the current monitoring circuit of the present invention;

[0026] Figure 3 This is a schematic diagram of the circuit providing the bias current of the present invention;

[0027] Figure 4 This is a flowchart illustrating the execution of an LED driving method based on a 3D printer according to the present invention. Detailed Implementation

[0028] The technical solution of the present invention will now be described in more detail with reference to the accompanying drawings and embodiments.

[0029] Mobile terminals implementing various embodiments of the present invention will now be described with reference to the accompanying drawings. In the following description, suffixes such as "module," "part," or "unit" used to denote elements are used only for the convenience of the description of the present invention and have no specific meaning in themselves. Therefore, "module" and "part" can be used interchangeably.

[0030] Mobile terminals can be implemented in various forms. For example, the terminals described in this invention may include mobile terminals such as mobile phones, smartphones, laptops, digital broadcast receivers, PDAs (personal digital assistants), PADs (tablet computers), PMPs (portable multimedia players), navigation devices, etc., as well as fixed terminals such as digital TVs, desktop computers, etc. Hereinafter, it will be assumed that the terminal is a mobile terminal. However, those skilled in the art will understand that, in addition to elements specifically designed for mobile purposes, the construction according to embodiments of the present invention can also be applied to fixed-type terminals.

[0031] Existing photopolymer 3D printers include SLA, DLP, and LCD types. In LCD photopolymer 3D printers, the core operation involves slicing the object to be printed into layers of images using a computer, displaying these layers on an LCD screen, and then curing the resin layers with ultraviolet light. In this way, each cured resin layer is stacked to form a solid. The light intensity parameter is critical during the photopolymerization process of each layer, as this parameter directly affects the thickness and size of each cured resin layer. Therefore, controlling the light intensity of the light source directly affects the printing accuracy of the machine.

[0032] Generally, LCD photopolymer 3D printers use LED chips as their light source. Due to the photoelectric characteristics of LEDs, the greater the current flowing through an LED within its current limit parameter range, the higher its brightness. In other words, the brightness of an LED is directly proportional to the current passing through it.

[0033] Currently, the brightness adjustment of LEDs is not precise enough. Because they use ultraviolet light to cure resin layers of images, each cured resin sheet is stacked to form a solid. The brightness parameter is very important during the curing process of each layer. This parameter directly affects the thickness and size of each cured resin layer. Therefore, the control of the light source brightness directly affects the printing accuracy of the machine. So, it is necessary to improve the precision of brightness adjustment.

[0034] To enable those skilled in the art to understand the technical solution of the present invention more clearly, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0035] like Figure 1-4 The above describes an LED driving method for an LCD printer, the method comprising the following steps:

[0036] Step 1: Record in advance the correspondence between LED brightness and current value, as well as the mapping relationship between the stability of current value and the printing accuracy of LCD printer. Then, determine whether to turn on the LED current value monitoring circuit based on the received data. The received data is the quantization level of printing accuracy input by the user.

[0037] Step 2: When the received user's printing accuracy requirement level is greater than the first preset value, the LED current value monitoring circuit is turned on, and a real-time signal of the current value is sent to the microcontroller connected to the administrator terminal device. When the received user's printing accuracy requirement level is less than the first preset value, the LED current value monitoring circuit is not turned on.

[0038] Step 3: The microcontroller uses a timer to capture the changes in the received real-time feedback current value I at preset time intervals Δt. Δt When the change in current value exceeds the stability of the current value corresponding to the received user-inputted printing precision quantization level, a first time period T is set, and the change in current value within the first time period is statistically analyzed. The microcontroller then sends the precision quantization level input by the user and the change in current value within the first time period to the management terminal device.

[0039] Preferably, the current monitoring circuit further converts the collected current value into a digital signal and sends it to the microcontroller via a digital signal processing unit.

[0040] Preferably, the current monitoring circuit further includes acquiring the bias current driving the LED, inputting the bias current from terminal B, and monitoring the real-time current value at terminal A. In the current monitoring circuit, one end of the first resistor and the first capacitor are connected to port B, and the other end is connected to port A. The second resistor and the third resistor are connected in parallel and then connected between port B and port A, and port A is grounded.

[0041] Preferably, the bias current of the driving LED is the current value corresponding to the current mirror of the driving LED current.

[0042] Preferably, the microcontroller uses a timer to capture the changes in the received real-time feedback current value I at preset time intervals Δt. Δt Further, it includes: recording the current value I1 at time t1, and recording the current value I2 at time t2, with the following equation:

[0043] t2 = t1 + Δt;

[0044] and I Δt =I2-I1.

[0045] Preferably, setting a first time period T and statistically analyzing the current value changes within the first time period further includes: T = n × I Δt Record n+1 current values ​​and analyze the changes in the difference between two adjacent current values.

[0046] Preferably, based on the quantization level of printing accuracy mapped to the current value changes within the first time period, the n current value changes I are... Δt The average value of the corresponding quantization level of printing precision is calculated. If the calculated quantization level value is greater than the precision quantization level value entered by the user, the current printing job will not be stopped, and the user will be informed of the printing precision fluctuation of the current printing job.

[0047] Preferably, if the calculated quantization level value is less than the precision quantization level value input by the user, an alarm is sent to the printing equipment administrator.

[0048] Preferably, the administrator terminal device is one or more of the following: mobile phone, smartphone, laptop computer, digital broadcast receiver, PDA, PAD, and desktop computer.

[0049] The present invention also discloses an LED driving circuit for an LCD printer, including the functional modules corresponding to the driving method described above.

[0050] In this embodiment, it is found that in the prior art, the light source control instructions corresponding to the slice cross-section data are obtained by the light source driving circuit. This can be done either by obtaining the light source control instructions for each layer of the printed model before printing the layer structure, or by obtaining the light source control instructions for that layer when preparing to print it. That is, the working states of multiple light sources are controlled according to the light source control instructions to complete the printing of the layer structure. Before printing the layer structure, the working states of the light sources are controlled according to the light source control instructions corresponding to the slice cross-section data of the layer structure, such as which light sources operate in the first working state (generally a high-power state), and others in the second working state (generally a low-power but high-luminous-efficiency state). The light source states are then maintained until the layer structure is printed. However, this method cannot provide more precise control over the light sources. This embodiment, by mapping the stability of the current value to the printing accuracy of the LCD printer, determines whether to activate the LED current value monitoring circuit based on the received data, thereby achieving stable LED driving without requiring separate limitations on the working states.

[0051] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0052] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0053] While the invention has been described above with reference to various embodiments, it should be understood that many changes and modifications can be made without departing from the scope of the invention. Therefore, the detailed description above is intended to be illustrative rather than restrictive, and it should be understood that the following claims (including all equivalents) are intended to define the spirit and scope of the invention. These embodiments should be understood as illustrative only and not as limiting the scope of protection of the invention. After reading the description of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent changes and modifications also fall within the scope defined by the claims of this invention.

Claims

1. An LED driving method for an LCD printer, characterized in that, The driving method includes the following steps: Step 1: Record in advance the correspondence between LED brightness and current value, as well as the mapping relationship between the stability of current value and the printing accuracy of LCD printer. Then, determine whether to turn on the LED current value monitoring circuit based on the received data. The received data is the quantization level of printing accuracy input by the user. Step 2: When the received user's printing accuracy requirement level is greater than the first preset value, the LED current value monitoring circuit is turned on, and a real-time signal of the current value is sent to the microcontroller connected to the administrator terminal device. When the received user's printing accuracy requirement level is less than the first preset value, the LED current value monitoring circuit is not turned on. Step 3: The microcontroller uses a timer to capture the changes in the received real-time feedback current value I at preset time intervals Δt. Δt When the change in current value exceeds the stability of the current value corresponding to the received user-inputted printing precision quantization level, a first time period T is set, and the change in current value within the first time period is statistically analyzed. The microcontroller then sends the precision quantization level input by the user and the change in current value within the first time period to the management terminal device.

2. The LED driving method for an LCD printer as described in claim 1, characterized in that, The current monitoring circuit further converts the collected current value into a digital signal and sends it to the microcontroller via a digital signal processing unit.

3. The LED driving method for an LCD printer as described in claim 2, characterized in that, The current monitoring circuit further includes acquiring the bias current driving the LED, inputting the bias current from terminal B, and monitoring the real-time current value at terminal A. In the current monitoring circuit, one end of the first resistor and the first capacitor are connected to port B, and the other end is connected to port A. The second resistor and the third resistor are connected in parallel and then connected between port B and port A, and port A is grounded.

4. The LED driving method for an LCD printer as described in claim 3, characterized in that, The bias current of the driving LED is the current value corresponding to the current mirror of the driving LED current.

5. The LED driving method for an LCD printer as described in claim 4, characterized in that, The microcontroller uses a timer to capture the changes in the received real-time feedback current value I at preset time intervals Δt. Δt Further, it includes: recording the current value I1 at time t1, and recording the current value I2 at time t2, with the following equation: t2 = t1 + Δt; and I Δt =I2-I1.

6. The LED driving method for an LCD printer as described in claim 5, characterized in that, Setting a first time period T and statistically analyzing the current value changes within the first time period further includes: T = n × I Δt Record n+1 current values ​​and analyze the changes in the difference between two adjacent current values.

7. The LED driving method for an LCD printer as described in claim 6, characterized in that, Based on the quantization level of printing accuracy mapped to the current value changes within the first time period, for n current value changes I Δt The average value of the corresponding quantization level of printing precision is calculated. If the calculated quantization level value is greater than the precision quantization level value entered by the user, the current printing job will not be stopped, and the user will be informed of the printing precision fluctuation of the current printing job.

8. The LED driving method for an LCD printer as described in claim 7, characterized in that, If the calculated quantization level value is less than the precision quantization level value entered by the user, an alarm will be sent to the printing equipment administrator.

9. The LED driving method for an LCD printer as described in claim 1, characterized in that, The administrator terminal device is one or more of the following: mobile phone, smartphone, laptop, digital broadcast receiver, PDA, PAD, and desktop computer.

10. An LED driving circuit for an LCD printer, characterized in that, Includes the functional modules corresponding to the driving method described in any one of claims 1-9.

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