Brightness detection circuit

Abstract

The utility model relates to the technical field of light detection, and discloses a brightness detection circuit, which comprises a light intensity acquisition module, a current selection module and a current conversion module, and is characterized in that the light intensity acquisition module comprises a plurality of brightness sensors and can acquire light signals at different acquisition stations of a light source and convert the light signals into current signals; the current selection module can select the current output by one brightness sensor to enter the current conversion module, and each brightness sensor can collect the optical signal of the corresponding collection station, thereby achieving the selection of the collection stations. And the current conversion module can convert the selected current signal into a voltage signal to obtain a brightness value. The circuit hardware realizes multiplexing, and can select a signal path of the brightness sensor so as to select an acquisition station, thereby avoiding the condition that a brightness probe cable needs to be manually selected and replaced when a preset object performs brightness acquisition at different acquisition stations, and further improving the reliability of a detection result of the brightness test device.

Description

Technical Field

[0001] The present application relates to the field of light detection technology, and in particular to a brightness detection circuit. Background Art

[0002] In the past, in order to detect the brightness of different light-emitting surfaces of flip-chip chips, the LED tester needs to set up different brightness acquisition hardware for different light-emitting surfaces, and manually select the probe coaxial cable corresponding to the light-emitting surface according to the front and back of the light-emitting surface. This will make the connector loose, and when performing long-term brightness tests, there will be consistency deviations in the brightness value, resulting in reduced reliability of brightness detection. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model proposes a brightness detection circuit, which uses the same circuit module to perform time-sharing detection on the brightness of different light-emitting surfaces of a light source to obtain the brightness test value of each light-emitting surface, and does not require setting different brightness acquisition hardware for different light-emitting surfaces, nor does it require manual selection of the probe coaxial cable, thereby solving the problem of low reliability of brightness testing.

[0004] The utility model provides a brightness detection circuit, comprising:

[0005] A light source, the light source having a first light emitting surface and a second light emitting surface; the first light emitting surface is used to emit a first light signal, and the second light emitting surface is used to emit a second light signal;

[0006] A light intensity acquisition module, the light intensity acquisition module comprising a first brightness sensor and a second brightness sensor, the first brightness sensor being used to convert the first light signal into a first current; the second brightness sensor being used to convert the second light signal into a second current;

[0007] a current selection module, the current selection module being connected to the first brightness sensor and the second brightness sensor respectively, and the current selection module being used to select the first current and the second current to obtain a target current;

[0008] A current conversion module is used to perform current conversion according to the target current to obtain a brightness value of the light source.

[0009] The brightness detection circuit proposed in the embodiment of the present application includes a light intensity acquisition module, a current selection module and a current conversion module. The light intensity acquisition module includes a first brightness sensor and a second brightness sensor, which can collect light signals at different acquisition stations of the light source, i.e., different light-emitting surfaces, and convert the light signals into current signals. The current collected by the first brightness sensor is the first current, and the current collected by the second brightness sensor is the second current. The current selection module is connected to the first brightness sensor and the second brightness sensor, and can select the first current or the second current to enter the current conversion module. Since each brightness sensor can collect the light signal of the corresponding acquisition station, the selection of the acquisition station is realized. The current conversion module can convert the first current or the second current into a voltage signal, i.e., obtain the brightness value. The circuit realizes multiplexing in hardware, can select the signal path of the brightness sensor, and then select the acquisition station, avoiding the situation where the brightness probe cable needs to be manually selected to be replaced when the preset object performs brightness acquisition at different acquisition stations, thereby improving the reliability of the detection results of the brightness test device.

[0010] In some embodiments, the current selection module includes a first switch and a second switch, the first switch is connected to the first brightness sensor, and the first switch is used to select the first current as the target current according to a first closed state of the first switch; the second switch is connected to the second brightness sensor, and the second switch is used to select the second current as the target current according to a second closed state of the second switch.

[0011] In some embodiments, the current conversion module includes multiple current conversion channels and a first amplification module, and the multiple current conversion channels are respectively connected in parallel with the first amplification module. The current conversion module is used to select a target current conversion channel from the multiple current conversion channels according to the target current, and perform current conversion on the target current according to the target current conversion channel and the first amplification module to obtain the brightness value.

[0012] In some embodiments, the first amplification module includes a first operational amplifier, the first operational amplifier having a first non-inverting input terminal, a first inverting input terminal and a first output terminal, the first inverting input terminal is respectively connected to the first terminal of each of the current conversion channels, the first output terminal is respectively connected to the second terminal of each of the current conversion channels, and the first non-inverting input terminal is respectively connected to the first brightness sensor and the second brightness sensor.

[0013] In some embodiments, the current conversion module further includes a filtering module, which is connected in parallel with any of the current conversion channels and is used to filter the current in the current conversion channel.

[0014] In some embodiments, the first amplification module further includes a bidirectional protection diode; the bidirectional protection diode is respectively connected to the first inverting input terminal and the first non-inverting input terminal.

[0015] In some embodiments, the current conversion module further includes a second amplification module, the second amplification module is connected to the first amplification module, and the second amplification module is used to amplify the signal output by the first amplification module.

[0016] In some embodiments, the second amplification module includes a second operational amplifier and an amplification factor selection module, the amplification factor selection module is connected to the second operational amplifier, the amplification factor selection module is used to determine the amplification factor; the second operational amplifier is used to amplify the signal output by the first amplification module according to the amplification factor.

[0017] In some embodiments, the brightness detection circuit further includes a signal processing module, which is connected to the current conversion module and is used to perform signal processing on the brightness value.

[0018] In some embodiments, the brightness detection circuit further includes an industrial computer module, which is connected to the signal processing module and is used to perform data correction on the brightness value processed by the signal processing module.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention is further described below with reference to the accompanying drawings and embodiments, wherein:

[0021] Figure 1 A circuit structure diagram of a brightness detection circuit provided in an embodiment of the utility model;

[0022] Figure 2 A module schematic diagram of a brightness detection circuit provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0023] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0024] In the description of the present invention, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0025] In the description of the present utility model, "several" means more than one, "many" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used to distinguish the technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0026] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0027] In the description of the utility model, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0028] First, some nouns involved in this application are analyzed:

[0029] LOP (Lumen Output Per Watt): is a unit used to measure the brightness efficiency of a light source. LOP stands for light output per watt and is used to measure the energy efficiency of a light source.

[0030] In the past, in order to detect the different light-emitting surfaces of the flip-chip, the LED tester needs to set up the corresponding brightness acquisition hardware at different brightness stations, and manually select and replace the coaxial cable of the front or back integrating sphere brightness probe, which causes the connector to loosen. Therefore, when performing long-term brightness testing, the consistency of the brightness value will deviate. Therefore, the existing brightness test device has the problem of low reliability of the test results.

[0031] Based on this, a brightness detection circuit is provided in an embodiment of the present application, which is specifically described through the following embodiments.

[0032] Figure 1 is a circuit structure diagram of a brightness detection circuit provided in an embodiment of the present application, Figure 2 This is a module schematic diagram of a brightness detection circuit provided in an embodiment of the present utility model. The brightness detection circuit provided in an embodiment of the present application includes: a light source, a light intensity acquisition module, a current selection module, a current conversion module, a signal processing module and an industrial computer module.

[0033] The light source has a first light emitting surface and a second light emitting surface, the first light emitting surface is used to emit a first light signal, and the second light emitting surface is used to emit a second light signal. The light source can be an LED chip, the first light emitting surface can be the front side of the LED chip, and the second light emitting surface can be the back side of the LED chip.

[0034] The light intensity acquisition module includes a first brightness sensor J1 and a second brightness sensor J2. The first brightness sensor J1 is used to convert a first light signal into a first current, and the second brightness sensor J2 is used to convert a second light signal into a second current.

[0035] Specifically, the first brightness sensor J1 and the second brightness sensor J2 are brightness probes that can convert optical signals into electrical signals, wherein the optical signal emitted by the first light-emitting surface is the first optical signal, the first brightness sensor J1 receives the first optical signal, converts the first optical signal into an electrical signal, and obtains a first current, at which point the first brightness sensor is located at the front photoelectric collection station. The optical signal emitted by the second light-emitting surface is the second optical signal, the second brightness sensor J2 receives the second optical signal, converts the second optical signal into an electrical signal, and obtains a second current, at which point the second brightness sensor is located at the back photoelectric collection station. In some embodiments, the brightness sensor is disposed inside an integrating sphere, the integrating sphere receives light emitted by a light source, the light is diffusely reflected inside the integrating sphere to form light with uniform light intensity, which is received by the brightness sensor, thereby causing the brightness sensor to output a stable light intensity sensing signal.

[0036] Among them, pin 1 of the first brightness sensor J1 is the first output pin, pin 2 of the first brightness sensor J1 is the second output pin, pin 1 of the second brightness sensor J2 is the third output pin, and pin 2 of the second brightness sensor J2 is the fourth output pin.

[0037] The current selection module is connected to the first brightness sensor J1 and the second brightness sensor J2 respectively. The current selection module is used to select the first current and the second current to obtain a target current.

[0038] In some embodiments, the current selection module includes a first switch K1 and a second switch K2, wherein the first end of the first switch K1 is connected to the first output pin, and the second end of the first switch K1 is respectively connected to the first end of the first resistor R1 and the first end of the bidirectional protection diode DD1, and the first switch K1 is used to select the first current as the target current according to the first closed state of the first switch K1. The first end of the second switch K2 is connected to the third output pin, and the second end of the first switch K1 is also connected to the second end of the second switch K2, and the second switch K2 is used to select the second current as the target current according to the second closed state of the second switch K2. The target current is the current that finally flows into the current conversion module after being selected by the current selection module. Specifically, closing the first switch K1 selects the first current to enter the current conversion module, and the second switch K2 is disconnected at this time. Closing the second switch K2 selects the second current to enter the current conversion module, and the first switch K1 is disconnected at this time.

[0039] In some embodiments, the first switch K1 and the second switch K2 may be relays. The preset object may select the photoelectric signal acquisition station by software or program setting, so as to realize the corresponding relay disconnection and closing, and then switch the signal path of the brightness sensor. In the scene of LED chip brightness detection, any front or back side brightness value can be freely selected to measure, so that both the front-mounted LED chip and the flip-down LED chip can be tested on the transparent carrier test equipment.

[0040] The current conversion module is used to convert the current according to the target current to obtain the brightness value of the light source. The brightness value is the light intensity brightness test value (LOP, Lumen Output Per Watt).

[0041] The brightness detection circuit proposed in the embodiment of the present application includes a light intensity acquisition module, a current selection module and a current conversion module. The light intensity acquisition module includes a first brightness sensor and a second brightness sensor, which can collect light signals at different collection stations of the light source and convert the light signals into current signals. The current collected by the first brightness sensor is the first current, and the current collected by the second brightness sensor is the second current. The current selection module is connected to the first brightness sensor and the second brightness sensor, and can select the first current or the second current to enter the current conversion module. Since each brightness sensor can collect the light signal of the corresponding collection station, the selection of the collection station is realized. The current conversion module can convert the first current or the second current into a voltage signal, that is, obtain the brightness value. The circuit realizes multiplexing in hardware, and only needs to use the same hardware to select the signal path of the brightness sensor, and then select the collection station, avoiding the situation where the brightness probe cable needs to be manually selected to replace when the preset object collects the brightness of different collection stations, thereby improving the reliability of the detection result of the brightness test device.

[0042] In some embodiments, the current conversion module includes multiple current conversion channels and a first amplification module, and the multiple current conversion channels are respectively connected in parallel with the first amplification module. The current conversion module is used to select a target current conversion channel from the multiple current conversion channels according to the target current, and perform current conversion on the target current according to the target current conversion channel and the first amplification module to obtain a brightness value.

[0043] Specifically, the current conversion channel is a series circuit of a resistor and a relay. In the embodiment of the present application, the current conversion module has 5 current conversion channels: the first current conversion channel includes a second resistor R2 and a third switch K3, the first end of the second resistor R2 is respectively connected to the second end of the first switch K1 and the first end of the first resistor R1, the second end of the second resistor R2 is connected to the first end of the third switch K3, and the second end of the third switch K3 is respectively connected to the second end of the ninth resistor R9 and the first end of the tenth resistor R10. The second current conversion channel includes a third resistor R3 and a fourth switch K4, the third resistor R3 and the fourth switch K4 are connected in series, and the second current conversion channel is connected in parallel with the first current conversion channel. The third current conversion channel includes a fourth resistor R4 and a fifth switch K5, the fourth resistor R4 and the fifth switch K5 are connected in series, and the third current conversion channel is connected in parallel with the second current conversion channel. The fourth current conversion channel includes a fifth resistor R5 and a sixth switch K6, the fifth resistor R5 and the sixth switch K6 are connected in series, and the fourth current conversion channel is connected in parallel with the third current conversion channel. The fifth current conversion channel includes a sixth resistor R6 and a seventh switch K7, the sixth resistor R6 and the seventh switch K7 are connected in series, and the fifth current conversion channel is connected in parallel with the fourth current conversion channel. Among them, the third switch K3, the fourth switch K4, the fifth switch K5, the sixth switch K6 and the seventh switch K7 can be normally open relays.

[0044] In some embodiments, each current conversion channel can achieve different current conversion resolutions. The resistance value in the current conversion channel can be set so that different current conversion channels can pass through different current ranges, thereby achieving different conversion resolutions for different current conversion channels. For example, the current conversion module allows a maximum voltage of 1V and a minimum voltage of 0.1V. At this time, the resistance value of the second resistor R2 is set to 100Ω, the third switch K3 is closed, and the fourth switch K4, the fifth switch K5, the sixth switch K6 and the seventh switch K7 are opened, that is, the first current conversion channel is selected for current conversion. At this time, the second resistor R2 is used as a sampling resistor. Therefore, the maximum current allowed to be measured in the first current conversion channel is 10mA, and the minimum current allowed to be measured is 1mA. The conversion resolution of the channel is 10mA / 1V. Similarly, the resistance of the third resistor R3 is set to 1kΩ, the fourth switch K4 is closed, and the third switch K3, the fifth switch K5, the sixth switch K6 and the seventh switch K7 are opened, that is, the second current conversion channel is selected for current conversion. At this time, the third resistor R3 is used as a sampling resistor, and the maximum current allowed to be measured in the first current conversion channel is 1mA, and the minimum current allowed to be measured is 0.1mA, and the conversion resolution of the channel is 1mA / 1V.

[0045] By setting the resistance values ​​in multiple current conversion channels, current-voltage conversion in different ranges is achieved, the coverage of photoelectric signals collected by photoelectric sensors is improved, and all existing LED chip testing scenarios are covered. At the same time, there is no significant difference in the conversion accuracy of photoelectric signals of different intensities. When testing LED chips, different current conversion channels can be selected according to the brightness value range of LED chips or other light source products, which can ensure that the signal is always within a high signal-to-noise ratio collection range, thereby ensuring the collection accuracy and repeatability of different brightness.

[0046] In some embodiments, the first amplification module includes a first operational amplifier OP1, a bidirectional protection diode DD1, a seventh resistor R7, an eighth resistor R8 and a ninth resistor R9. The first operational amplifier OP1 has a first positive input terminal, a first negative input terminal and a first output terminal. The first negative input terminal is respectively connected to the first end of each current conversion channel, the first output terminal is respectively connected to the second end of each current conversion channel, and the first positive input terminal is respectively connected to the first brightness sensor J1 and the second brightness sensor J2.

[0047] Specifically, the first inverting input terminal is connected to the second end of the first resistor R1, the first non-inverting input terminal is connected to the second end of the bidirectional protection diode DD1, the first non-inverting input terminal is connected to the first reference level SENS_G, the second output pin and the fourth output pin are connected to the first reference level SENS_G through the cable shielding layer or the cable signal low level terminal, and the first reference level is connected to the second reference level AGND through the seventh resistor R7. The first output terminal is respectively connected to the first end of the eighth resistor R8 and the first end of the ninth resistor R9, the second end of the eighth resistor R8 is connected to the second reference level AGND, the eighth resistor R8 acts as a ground discharge resistor, the second end of the ninth resistor R9 is also connected to the first section of the tenth resistor R10, and the ninth resistor R9 acts as an output current limiting resistor.

[0048] It should be noted that the target current has two paths, one path is to flow through the first resistor R1 and input to the first inverting input terminal to be amplified, and the other path is to flow into a current conversion channel. The first operational amplifier OP1 outputs the LOP signal through the ninth resistor R9 and the selected current conversion channel to the first end of the first resistor R1. At this time, the input impedance of the first operational amplifier OP1 is infinite and is in a feedback balance state. The voltage of the first positive input terminal is equal to that of the first inverting input terminal. The current of the LOP signal from the first resistor R1 to the first inverting input terminal can be ignored, so the voltages at both ends of the first resistor R1 are equal.

[0049] Among them, the bidirectional protection diode DD1 can absorb energy in the case of overvoltage in the LED chip brightness detection circuit to protect the detection circuit from voltage surge and overvoltage damage.

[0050] In some embodiments, the current conversion module further includes a filtering module, which is connected in parallel with any current conversion channel and is used to filter the current in the current conversion channel.

[0051] Specifically, the filtering module includes a first resistor R1, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4 and a fifth capacitor C5, the second end of the first resistor R1 is also connected to the first end of the first capacitor C1, the first end of the second capacitor C2, the first end of the third capacitor C3, the first end of the fourth capacitor C4 and the first end of the fifth capacitor C5, the second end of the first capacitor C1 is connected to the second end of the second resistor R2, the second end of the second capacitor C2 is connected to the second end of the third resistor R3, the second end of the third capacitor C3 is connected to the second end of the fourth resistor R4, the second end of the fourth capacitor C4 is connected to the second end of the fifth resistor R5, and the second end of the fifth capacitor C5 is connected to the second end of the sixth resistor R6. When a current conversion channel is turned on, the capacitor connected to the current conversion channel and the first resistor R1 form a filtering circuit. For example, when the third switch K3 is closed, the first current conversion channel is turned on. At this time, the first capacitor C1 and the first resistor R1 connected to the first current conversion channel form a filtering circuit of the current conversion channel, and the current signal frequency is filtered. The filtering parameter matches the current signal range corresponding to the current conversion channel.

[0052] In some embodiments, the current conversion module further includes a second amplification module, which is connected in series with the first amplification module, and is used to amplify the signal output by the first amplification module.

[0053] The second amplification module includes a second operational amplifier OP2, a tenth resistor R10, a sixth capacitor C6, a seventh capacitor C7 and an amplification factor selection module, and the amplification factor selection module is connected to the second operational amplifier OP2. Specifically, the second operational amplifier OP2 has a second non-inverting input terminal, a second inverting input terminal and a second output terminal, and the amplification factor selection module includes an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13 and an eighth switch K8. The second positive phase input terminal is connected to the second end of the tenth resistor R10, the first end of the eleventh resistor R11 is connected to the second reference level AGND, the second end of the eleventh resistor R11 is respectively connected to the second positive phase input terminal, the twelfth resistor R12 and the sixth capacitor C6, the twelfth resistor R12 is connected in series with the thirteenth resistor R13, the sixth capacitor C6 is connected in parallel with the twelfth resistor R12, the seventh capacitor C7 is connected in parallel with the thirteenth resistor R13, the eighth switch K8 is connected in parallel with the thirteenth resistor R13, the second output terminal is connected to the thirteenth resistor R13, the eighth switch K8 is connected to the thirteenth resistor R13, and the second output terminal is used to output the final LOP signal. The amplification factor selection module is used to determine the amplification factor, and the second operational amplifier OP2 is used to amplify the signal output by the first amplification module according to the amplification factor.

[0054] Specifically, when K8 is closed, the first amplification factor is (R12+R13) / R13, and when K8 is disconnected, the second amplification factor is (R13+R12+R11) / R11. The first amplification factor and the second amplification factor can be adjusted by setting the resistance values ​​of the eleventh resistor R11, the twelfth resistor R12, and the thirteenth resistor R13. In some embodiments, the first amplification factor can be 10, the second amplification factor can be 100, and the voltage limit range of the LOP signal output by the second amplification module is 0-10V. Therefore, when the output voltage range of the first amplification module is 0.1-1V, the second amplification module selects the first amplification factor as the final amplification factor, and when the output voltage range of the first amplification module is 0.01-0.1V, the second amplification module selects the second amplification factor as the final amplification factor.

[0055] It is understandable that after the current signal is converted into a voltage signal, the two-stage amplification and filtering of the signal is realized through the first amplification module and the second amplification module, which can improve the response speed and noise suppression effect when amplifying weak signals. Compared with the one-stage amplification and filtering circuit, the one-stage amplification and filtering circuit converts the 10nA signal to a 1V voltage signal, and the one-stage amplification and filtering circuit requires a 100MΩ resistor. The two-stage filtering and amplification circuit can use a 1MΩ resistor when the first stage amplification is 1 million times amplified, and a 100K resistor when the second stage amplification is 100 times amplified. Low-noise resistors with resistance values ​​higher than 1MΩ are expensive. If low-noise resistors are used, the circuit cost will increase significantly. Therefore, in the circuit with the same signal-to-noise ratio, the circuit cost of using two-stage amplification is better than that of the one-stage amplification circuit, and better filtering effect can be achieved after two-stage filtering.

[0056] In some embodiments, the brightness detection circuit further includes a signal processing module, the signal processing module is connected to the current conversion module, and the signal processing module is used to perform signal processing on the brightness value. The signal processing module is also connected to the light source to make the light source emit light. The signal conditioning operations performed by the signal processing module may include filtering, denoising, calibration, limiting, and phase correction.

[0057] In some embodiments, the brightness detection circuit further includes an industrial computer module, which is connected to the signal processing module and is used to perform data correction on the brightness value processed by the signal processing module. The operation of the industrial computer module on the brightness value may be to convert the brightness value from an analog signal to a digital signal, perform average calculation, correction calculation, and data analysis on the brightness value.

[0058] In some embodiments, the brightness detection circuit further includes a power supply for supplying power to the first operational amplifier OP1 and the second operational amplifier OP2, wherein the voltage provided by the power supply may be ±15V.

[0059] Next, combine Figure 2, the application scenarios of the brightness detection circuit proposed in the embodiment of the utility model are specifically introduced.

[0060] The signal processing module is connected to multiple light sources, and current is applied to the multiple light sources to make them work. The light emitted by each light source is received by a corresponding integrating sphere. The light is diffusely reflected by the integrating sphere, so that the brightness sensor inside the integrating sphere receives a uniform light signal and converts the light signal into a current signal, which is transmitted to the current conversion module through a cable. The current conversion module converts the current signal into a voltage signal. The voltage signal is amplified by two stages of filtering to obtain a LOP signal. This process realizes the conversion of the photoelectric signal into a voltage signal with a high signal-to-noise ratio. The LOP signal is then transmitted to the signal processing module through a cable. The signal processing module performs signal conditioning on the LOP signal and then transmits it to the industrial computer module. The industrial computer module performs analog-to-digital conversion on the LOP signal, and performs average and correction operations on the LOP value. The circuit provided in the embodiment of the present application can realize fast, high-precision, high-stability, and high-consistency LOP value measurement of LED chips, and can also realize time-sharing measurement of the brightness values ​​of different LED chips.

[0061] The embodiments of the utility model are described in detail above in conjunction with the accompanying drawings, but the utility model is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the utility model. In addition, the embodiments of the utility model and the features in the embodiments can be combined with each other without conflict.

Claims

1. A brightness detection circuit, characterized in that: The brightness detection circuit comprises: A light source, the light source having a first light emitting surface and a second light emitting surface; the first light emitting surface is used to emit a first light signal, and the second light emitting surface is used to emit a second light signal; A light intensity acquisition module, the light intensity acquisition module comprising a first brightness sensor and a second brightness sensor, the first brightness sensor being used to convert the first light signal into a first current; the second brightness sensor being used to convert the second light signal into a second current; a current selection module, the current selection module being connected to the first brightness sensor and the second brightness sensor respectively, and the current selection module being used to select the first current and the second current to obtain a target current; A current conversion module is used to perform current conversion according to the target current to obtain a brightness value of the light source.

2. The brightness detection circuit according to claim 1, characterized in that: The current selection module includes a first switch and a second switch, the first switch is connected to the first brightness sensor, and the first switch is used to select the first current as the target current according to a first closed state of the first switch; The second switch is connected to the second brightness sensor, and the second switch is used to select the second current as the target current according to a second closed state of the second switch.

3. The brightness detection circuit according to claim 1, characterized in that: The current conversion module includes multiple current conversion channels and a first amplification module. The multiple current conversion channels are respectively connected in parallel with the first amplification module. The current conversion module is used to select a target current conversion channel from the multiple current conversion channels according to the target current, and perform current conversion on the target current according to the target current conversion channel and the first amplification module to obtain the brightness value.

4. The brightness detection circuit according to claim 3, characterized in that: The first amplification module includes a first operational amplifier, which has a first non-inverting input terminal, a first inverting input terminal and a first output terminal. The first inverting input terminal is respectively connected to the first end of each current conversion channel, the first output terminal is respectively connected to the second end of each current conversion channel, and the first non-inverting input terminal is respectively connected to the first brightness sensor and the second brightness sensor.

5. The brightness detection circuit according to claim 4, characterized in that: The current conversion module further includes a filtering module, which is connected in parallel with any of the current conversion channels and is used to filter the current in the current conversion channel.

6. The brightness detection circuit according to claim 4, characterized in that: The first amplification module further includes a bidirectional protection diode; the bidirectional protection diode is connected to the first inverting input terminal and the first non-inverting input terminal respectively.

7. The brightness detection circuit according to claim 6, characterized in that: The current conversion module further includes a second amplifying module, which is connected to the first amplifying module and is used to amplify the signal output by the first amplifying module.

8. The brightness detection circuit according to claim 7, characterized in that: The second amplification module includes a second operational amplifier and an amplification factor selection module, the amplification factor selection module is connected to the second operational amplifier, the amplification factor selection module is used to determine the amplification factor; the second operational amplifier is used to amplify the signal output by the first amplification module according to the amplification factor.

9. The brightness detection circuit according to claim 8, characterized in that: The brightness detection circuit further includes a signal processing module, which is connected to the current conversion module and is used to perform signal processing on the brightness value.

10. The brightness detection circuit according to claim 9, characterized in that: The brightness detection circuit also includes an industrial computer module, which is connected to the signal processing module and is used to perform data correction on the brightness value processed by the signal processing module.

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