Light source brightness control device and endoscope

Abstract

The application discloses a light source brightness control device and an endoscope, and is applied to the field of light control. The device comprises a control module, a signal conversion module, a driving module and a light source. The signal conversion module is used for outputting a first voltage to the driving module according to a control signal, the first voltage is positively correlated with the control signal, the change rate of the first voltage is positively correlated with the current flowing through the light source, and the driving module is used for converting the first voltage into a PWM signal and outputting the PWM signal to the light source. On the basis that the signal conversion module outputs the first voltage according to the control signal, the change rate of the first voltage is also positively correlated with the current flowing through the light source. Under the condition that the control signal is unchanged, the smaller the current flowing through the light source, the smaller the change rate of the first voltage, and the brightness change of the light source is relatively slow.

Description

Technical Field

[0001] This invention relates to the field of light control, and in particular to a device for controlling the brightness of a light source and an endoscope. Background Technology

[0002] Endoscopic systems widely utilize LEDs as the core light-emitting device, whose output spectral morphology and brightness affect image color and brightness. In practical applications, spectral applications vary. Existing LED light sources exhibit a linear relationship between output spectral brightness and current; the current magnitude corresponds to a unique luminous flux output, and current adjustment follows the LED current-luminous flux characteristic curve. Control is achieved by multiples of the smallest current adjustment unit 'i', thereby controlling the light source brightness, with the circuit drive limited to the maximum current. The current-luminous flux characteristic curve has a steeper slope at lower currents, resulting in greater brightness changes in the LED due to adjustments within small current ranges, leading to abrupt changes in image brightness. Therefore, controlling the current and its corresponding LED brightness, as well as the rate and precision of adjustment, are crucial factors in achieving effective image brightness regulation. Summary of the Invention

[0003] The purpose of this invention is to provide a device for controlling the brightness of a light source and an endoscope. Under the condition that the control signal remains unchanged, the smaller the current flowing through the light source, the smaller the rate of change of the first voltage, and the slower the change in the brightness of the light source.

[0004] To solve the above-mentioned technical problems, the present invention provides a light source brightness control device, including a control module, a signal conversion module, a driving module and a light source;

[0005] The input terminal of the control module is connected to a control signal, the first output terminal of the control module is connected to the input terminal of the signal conversion module, the output terminal of the signal conversion module is connected to the first input terminal of the drive module, and the output terminal of the drive module is connected to the light source.

[0006] The control module is used to output the control signal to the signal conversion module. The signal conversion module is used to output a first voltage to the drive module according to the control signal. The first voltage is positively correlated with the control signal. The rate of change of the first voltage is positively correlated with the current flowing through the light source. The drive module is used to convert the first voltage into a PWM signal and output it to the light source.

[0007] Preferably, it also includes a voltage conversion module;

[0008] The first end of the voltage conversion module is connected to the output end of the drive module, and the second end of the voltage conversion module is connected to the light source;

[0009] The voltage conversion module is used to step down the voltage output by the drive module and output it to the light source.

[0010] Preferably, the voltage conversion module is a DC / DC converter.

[0011] Preferably, it also includes a feedback module;

[0012] The output terminal of the feedback module is connected to the second input terminal of the drive module. The feedback module is used to output a second voltage value to the drive module. The second voltage is positively correlated with the current flowing through the light source and positively correlated with the first voltage. The PWM signal satisfies that the second voltage is equal to the first voltage.

[0013] Preferably, a sampling resistor is also included;

[0014] The first end of the sampling resistor is connected to the output end of the driving module, and the second end of the sampling resistor is connected to the light source;

[0015] The feedback module is specifically used to output a second voltage value to the drive module based on the current flowing through the sampling resistor.

[0016] Preferably, the feedback module includes an amplifier;

[0017] The positive input terminal of the amplifier is connected to the first terminal of the sampling resistor, the inverting input terminal of the amplifier is connected to the second terminal of the sampling resistor, and the output terminal of the amplifier serves as the output terminal of the feedback module.

[0018] The amplifier is used to collect the current flowing through the sampling resistor and amplify it to convert it into a second voltage output.

[0019] Preferably, the feedback module further includes an adder;

[0020] The first input terminal of the adder is connected to the output terminal of the amplifier, the second input terminal of the adder is connected to the first reference voltage, and the output terminal of the adder is connected to the second input terminal of the driver module.

[0021] The adder is used to add the voltage output by the amplifier to the first reference voltage and then output the result. The first reference voltage is the start-up voltage.

[0022] Preferably, the light source is an LED lamp.

[0023] Preferably, the signal conversion module includes a digital-to-analog converter and a reference voltage output module;

[0024] The first output terminal of the control module is connected to the first input terminal of the digital-to-analog converter, the second output terminal of the control module is connected to the input terminal of the reference voltage output module, the output terminal of the reference voltage output module is connected to the second input terminal of the digital-to-analog converter, and the output terminal of the digital-to-analog converter serves as the output terminal of the signal conversion module.

[0025] The digital-to-analog converter is used to convert the control signal into an analog quantity and output a first voltage value to the drive module. The first voltage is positively correlated with the product of the second reference voltage and the analog quantity corresponding to the control signal. The second reference voltage is positively correlated with the current flowing through the light source.

[0026] To address the aforementioned technical problems, the present invention also provides an endoscope, including the aforementioned light source brightness control device, and further including a light source and a spectrum analyzer. The light source brightness control device is connected to the input end of the light source, and the output end of the light source is connected to the spectrum analyzer.

[0027] This application provides a light source brightness control device and endoscope, applicable to the field of light control. It includes a control module, a signal conversion module, a drive module, and a light source. The signal conversion module outputs a first voltage to the drive module based on a control signal. The first voltage is positively correlated with the control signal, and the rate of change of the first voltage is positively correlated with the current flowing through the light source. The drive module converts the first voltage into a PWM signal and outputs it to the light source. In addition to the signal conversion module outputting the first voltage based on the control signal, the rate of change of the first voltage is also positively correlated with the current flowing through the light source. Under the condition that the control signal remains constant, the smaller the current flowing through the light source, the smaller the rate of change of the first voltage, and the slower the change in the brightness of the light source. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the prior art and embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A schematic diagram of the structure of a light source brightness control device provided by the present invention;

[0030] Figure 2 A curve showing the relationship between light source current and brightness provided by the present invention;

[0031] Figure 3 A schematic diagram of another light source brightness control device provided by the present invention. Detailed Implementation

[0032] The core of this invention is to provide a light source brightness control device and an endoscope. Under the condition that the control signal remains unchanged, the smaller the current flowing through the light source, the smaller the rate of change of the first voltage, and the slower the change in the brightness of the light source.

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Figure 1 The present invention provides a schematic diagram of a light source brightness control device, which includes a control module 1, a signal conversion module 2, a drive module 3, and a light source 4;

[0035] The input terminal of control module 1 is connected to the control signal, the first output terminal of control module 1 is connected to the input terminal of signal conversion module 2, the output terminal of signal conversion module 2 is connected to the first input terminal of drive module 3, and the output terminal of drive module 3 is connected to the light source 4.

[0036] The control module 1 is used to output a control signal to the signal conversion module 2. The signal conversion module 2 is used to output a first voltage to the drive module 3 according to the control signal. The first voltage is positively correlated with the control signal, and the rate of change of the first voltage is positively correlated with the current flowing through the light source 4. The drive module 3 is used to convert the first voltage into a PWM signal and output it to the light source 4.

[0037] The endoscope system's light source 4 widely uses LEDs as its core light-emitting device, whose output spectral morphology and brightness affect image color and brightness. In practical applications, different spectral application modes exist. Currently, the output spectral brightness of the LED light source 4 has a linear relationship with the current; the current magnitude corresponds to a unique luminous flux output, and the current is adjusted according to the LED current-luminous flux characteristic curve. The brightness of the light source 4 is controlled by multiples of the smallest current adjustment unit i, with the circuit drive limited by the maximum current drive.

[0038] Figure 2 A curve showing the relationship between current and brightness of a light source 4 provided by the present invention;

[0039] The current-brightness characteristic curve has a steeper slope when the current is low, indicating that the LED brightness changes more significantly in the low-current region due to the adjustment unit, resulting in abrupt changes in image brightness. Therefore, controlling the current and the corresponding LED brightness, as well as adjusting the rate and precision of these changes, are key factors in achieving image brightness adjustment.

[0040] After the control signal is input to the control module 1, the control module 1 outputs the control signal to the signal conversion module 2. The signal conversion module 2 can output a first voltage to the drive module 3 according to the control signal. The drive module 3 can convert the first voltage into a PWM signal and output it to the light source 4 to power the light source 4, allowing the light source 4 to emit light. To solve the problems existing in the prior art, the first voltage is positively correlated with the control signal. That is, when the user or other device wants to increase the brightness of the light source 4, the first voltage will increase, which in turn will increase the current flowing through the light source 4, thus increasing the brightness of the light source 4. At the same time, considering that the slope of the current-brightness curve is larger when the current is small and smaller when the current is large, the first voltage changes more slowly when the current is small and changes more rapidly when the current is large, which can solve the problem of slow brightness adjustment in the prior art.

[0041] This application provides a brightness control device for a light source 4, applicable to the field of light control. It includes a control module 1, a signal conversion module 2, a drive module 3, and a light source 4. The signal conversion module 2 outputs a first voltage to the drive module 3 based on a control signal. The first voltage is positively correlated with the control signal, and the rate of change of the first voltage is positively correlated with the current flowing through the light source 4. The drive module 3 converts the first voltage into a PWM signal and outputs it to the light source 4. In addition to the signal conversion module 2 outputting the first voltage based on the control signal, the rate of change of the first voltage is also positively correlated with the current flowing through the light source 4. Under the condition that the control signal remains constant, the smaller the current flowing through the light source 4, the smaller the rate of change of the first voltage, and the slower the brightness change of the light source 4.

[0042] Based on the above embodiments:

[0043] Figure 3 A schematic diagram of another light source brightness control device provided by the present invention;

[0044] In a preferred embodiment, a voltage conversion module 5 is also included;

[0045] The first end of the voltage conversion module 5 is connected to the output end of the drive module 3, and the second end of the voltage conversion module 5 is connected to the light source 4.

[0046] The voltage conversion module 5 is used to step down the voltage output by the drive module 3 and output it to the light source 4.

[0047] Considering that the voltage of the PWM signal output by the drive module 3 is higher than the rated voltage of the light source 4, a voltage conversion module 5 is needed to step down the PWM signal and output it to the light source 4.

[0048] Alternatively, if the PWM signal output by the drive module 3 cannot meet the operating voltage of the light source 4, the voltage is boosted by the voltage conversion module 5 to supply power to the light source 4.

[0049] Specifically, the voltage conversion module 5 can increase or decrease the voltage to supply power to the light source 4, so as to meet the needs of the light source 4.

[0050] In a preferred embodiment, the voltage conversion module 5 is a DC / DC (direct current / direct current) converter.

[0051] Since the power supply for light source 4 is DC, a DC / DC converter is used to control the effective voltage output by adjusting its PWM (duty cycle) to meet the needs of light source 4.

[0052] In a preferred embodiment, a feedback module 6 is also included;

[0053] The output terminal of the feedback module 6 is connected to the second input terminal of the drive module 3. The feedback module 6 is used to output a second voltage value to the drive module 3. The second voltage is positively correlated with the current flowing through the light source 4 and positively correlated with the first voltage. The PWM signal satisfies that the second voltage is equal to the first voltage.

[0054] Considering that relying solely on the PWM signal output by the drive module 3 to power the light source 4 would result in an inaccurate first voltage output, potentially leading to deviations in the control of the light source 4, a feedback module 6 is implemented. The feedback module 6 outputs a second voltage to the drive module 3. Since the PWM signal output by the drive module 3 is positively correlated with the second voltage, the drive module 3 adjusts its output PWM signal based on the second voltage to ensure that the second voltage equals the first voltage. The feedback module 6 thus makes the voltage output by the drive module 3 more accurate.

[0055] As a preferred embodiment, a sampling resistor Rs is also included;

[0056] The first end of the sampling resistor is connected to the output end of the driving module 3, and the second end of the sampling resistor is connected to the light source 4.

[0057] The feedback module 6 is specifically used to output a second voltage value to the drive module 3 based on the current flowing through the sampling resistor.

[0058] The sampling resistor is connected in series with the light source 4. The current flowing through the sampling resistor is equal to the current flowing through the light source 4. The feedback module 6 can collect the current through the sampling resistor and output the second voltage value to drive the module 3.

[0059] In a preferred embodiment, the feedback module 6 includes an amplifier 61;

[0060] The positive input terminal of amplifier 61 is connected to the first terminal of the sampling resistor, the inverting input terminal of amplifier 61 is connected to the second terminal of the sampling resistor, and the output terminal of amplifier 61 serves as the output terminal of feedback module 6.

[0061] Amplifier 61 is used to collect the current flowing through the sampling resistor and amplify it to convert it into a second voltage output.

[0062] The second voltage is equal to A * Iout * R, where A is the amplification factor, Iout is the current, and R is the resistance of the sampling resistor. The current flowing through the sampling resistor is amplified by amplifier 61 and converted into the second voltage output, which is then used by drive module 3 to adjust the output PWM signal.

[0063] In a preferred embodiment, the feedback module 6 further includes an adder 62;

[0064] The first input terminal of adder 62 is connected to the output terminal of amplifier 61, the second input terminal of adder 62 is connected to the first reference voltage, and the output terminal of adder 62 is connected to the second input terminal of driver module 3;

[0065] Adder 62 is used to add the voltage output by amplifier 61 to the first reference voltage and output the result. The first reference voltage is the start-up voltage.

[0066] Considering the existence of an operational amplifier reference threshold, a first reference voltage is required to drive the light source 4. The light source 4 will only start when the first voltage reaches the first reference voltage. The second voltage = A*Iout*R + Vref1, where Vref1 is the first reference voltage.

[0067] In a preferred embodiment, the light source 4 is an LED lamp.

[0068] LED lights are lamps that use light-emitting diodes as the light source. Typically, silver or white glue is used to cure the semiconductor LED onto a bracket, then silver or gold wires are used to connect the chip and circuit board. The entire assembly is sealed with epoxy resin to protect the internal wiring, and finally, a housing is installed. LED lights offer advantages such as energy saving, long lifespan, environmental friendliness, and shock resistance. They can directly emit light of various colors, making them suitable for use as the light source in endoscopes.

[0069] In a preferred embodiment, the signal conversion module 2 includes a digital-to-analog converter 21 and a reference voltage output module 22;

[0070] The first output terminal of the control module 1 is connected to the first input terminal of the digital-to-analog converter 21, the second output terminal of the control module 1 is connected to the input terminal of the reference voltage output module 22, the output terminal of the reference voltage output module 22 is connected to the second input terminal of the digital-to-analog converter 21, and the output terminal of the digital-to-analog converter 21 serves as the output terminal of the signal conversion module 2.

[0071] The digital-to-analog converter 21 is used to convert the control signal into an analog quantity and output a first voltage value to drive the module 3. The first voltage is positively correlated with the product of the second reference voltage and the analog quantity corresponding to the control signal. The second reference voltage is positively correlated with the current flowing through the light source 4.

[0072] The output voltage of the digital-to-analog converter 21 is: First voltage = Vref2*d / D, where Vref2 is the second reference voltage output by the reference voltage output module 22, d is the output value of the control module 1, and D is the maximum resolution (adjustment level) of the device, determined by the unit adjustment value Vref2 / D output by module A. When d = D, the circuit outputs the corresponding maximum current, realizing the control relationship between d and output current. The first voltage = Vref2 / D*d is adjusted by changing the reference voltage. At this time, depending on the LED application mode, the corresponding LED current will also be different for each mode. The output value of Vref2 is modified by controlling the modification. When the output value of d remains unchanged, the output Vctrl can be changed by changing Vref2, thereby changing the output current value. At this time, by changing Vref2, the maximum current is determined by keeping the value of D unchanged, that is, it is associated with Vref2 and serves as the maximum current for different LED usage modes. That is, the value of D is the maximum adjustment value of the device accuracy. Without changing the device resolution D, modifying Vref2 can realize the adjustment of the first voltage, i.e., the output current. For example, the original maximum output current of 20A can be adjusted in D levels. After modifying Vref2, the output current is 2A, and the number of adjustable levels remains D. This satisfies the switching of the LED's maximum current in different modes, with the corresponding adjustment level being D. In low-current drive, the smaller the current, the more significant the mapping effect on luminous flux. The smaller the current, the larger the absolute value of the current's adjustment effect on luminous flux (brightness). By changing Vref2, the unit adjustment value Vref2 / D can be reduced. Therefore, by changing Vref, the luminous flux adjustment accuracy can be optimized. This allows for different modes, based on different maximum currents, while ensuring that the control D remains constant, thus guaranteeing current control accuracy.

[0073] This application also provides an endoscope, including the above-mentioned brightness control device for the light source 4, and also including the light source 4 and a spectrum analyzer. The brightness control device for the light source 4 is connected to the input end of the light source 4, and the output end of the light source 4 is connected to the spectrum analyzer.

[0074] Please refer to the above embodiments for a description of the endoscope provided in this application, and it will not be repeated here.

[0075] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, 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 limitations, 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.

[0076] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0077] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for controlling the brightness of a light source, characterized in that, Includes a control module, a signal conversion module, a drive module, and a light source; The input terminal of the control module is connected to a control signal, the first output terminal of the control module is connected to the input terminal of the signal conversion module, the output terminal of the signal conversion module is connected to the first input terminal of the drive module, and the output terminal of the drive module is connected to the light source. The control module is used to output the control signal to the signal conversion module. The signal conversion module is used to output a first voltage to the drive module according to the control signal. The first voltage is positively correlated with the control signal, and the rate of change of the first voltage is positively correlated with the current flowing through the light source. The drive module is used to convert the first voltage into a PWM signal and output it to the light source. It also includes a feedback module; The output terminal of the feedback module is connected to the second input terminal of the drive module. The feedback module is used to output a second voltage value to the drive module. The second voltage is positively correlated with the current flowing through the light source and positively correlated with the first voltage. The PWM signal satisfies that the second voltage is equal to the first voltage. The signal conversion module includes a digital-to-analog converter and a reference voltage output module; The first output terminal of the control module is connected to the first input terminal of the digital-to-analog converter, the second output terminal of the control module is connected to the input terminal of the reference voltage output module, the output terminal of the reference voltage output module is connected to the second input terminal of the digital-to-analog converter, and the output terminal of the digital-to-analog converter serves as the output terminal of the signal conversion module. The digital-to-analog converter is used to convert the control signal into an analog quantity and output a first voltage to the drive module. The first voltage is positively correlated with the product of the second reference voltage and the analog quantity corresponding to the control signal. The second reference voltage is positively correlated with the current flowing through the light source. Wherein, the first voltage = Vref2×d / D, Vref2 is the second reference voltage output by the reference voltage output module, d is the output value of the control module, and D is the maximum resolution of the device, i.e., the adjustment level; The reference voltage output module is used to change the output second reference voltage Vref2 and reduce the unit adjustment value Vref2 / D so as to ensure that the control D remains unchanged under different currents.

2. The light source brightness control device as described in claim 1, characterized in that, It also includes a voltage conversion module; The first end of the voltage conversion module is connected to the output end of the drive module, and the second end of the voltage conversion module is connected to the light source; The voltage conversion module is used to step down the voltage output by the drive module and output it to the light source.

3. The light source brightness control device as described in claim 2, characterized in that, The voltage conversion module is a DC / DC converter.

4. The light source brightness control device as described in claim 1, characterized in that, It also includes a sampling resistor; The first end of the sampling resistor is connected to the output end of the driving module, and the second end of the sampling resistor is connected to the light source; The feedback module is specifically used to output a second voltage value to the drive module based on the current flowing through the sampling resistor.

5. The light source brightness control device as described in claim 4, characterized in that, The feedback module includes an amplifier; The positive input terminal of the amplifier is connected to the first terminal of the sampling resistor, the inverting input terminal of the amplifier is connected to the second terminal of the sampling resistor, and the output terminal of the amplifier serves as the output terminal of the feedback module. The amplifier is used to collect the current flowing through the sampling resistor and amplify it to convert it into a second voltage output.

6. The light source brightness control device as described in claim 5, characterized in that, The feedback module also includes an adder; The first input terminal of the adder is connected to the output terminal of the amplifier, the second input terminal of the adder is connected to the first reference voltage, and the output terminal of the adder is connected to the second input terminal of the driver module. The adder is used to add the voltage output by the amplifier to the first reference voltage and then output the result. The first reference voltage is the start-up voltage.

7. The light source brightness control device as described in claim 1, characterized in that, The light source is an LED lamp.

8. An endoscope, characterized in that, The device includes a light source brightness control device as described in any one of claims 1 to 7, and further includes a light source and a spectrum analyzer, wherein the light source brightness control device is connected to the input end of the light source, and the output end of the light source is connected to the spectrum analyzer.

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