Composite LED module and water quality monitoring device using the same
Disclosed is a composite LED module comprising a 230±10 nm deep-ultraviolet light LED, a 275±10 nm deep-ultraviolet light LED, and 0 to 3 visible light LED(s), packed in a same substrate. Also disclosed are a water quality monitoring device and a water quality monitoring probe containing the composite LED module.
1. A multi-parameter water quality monitoring device, comprising:
a composite LED module, wherein the composite LED module comprises:
a 230±10 nm deep-ultraviolet light LED,
a 275±10 nm deep-ultraviolet light LED, and
0 to 3 visible light LED(s), wherein these LEDs are packaged on a substrate or circuited board and configured in such a way that each LED is switched on/off independently,
a U-shaped groove in which a water sample flows,
an ultraviolet-visible light detecting photodiode B,
a fluorescence detecting photodiode C, and
a band-pass filter.
2. The multi-parameter water quality monitoring device according to claim 1 , wherein the U-shaped groove comprises a quartz plate A, a quartz plate B, and a quartz plate C, wherein the quartz plate A and the quartz plate B are arranged opposite each other, and the quartz plate C is horizontally arranged on the bottom of the U-shaped groove and perpendicular to the quartz plate A and quartz plate B.
3. The multi-parameter water quality monitoring device according to claim 2 , wherein the light beam emitted from the composite LED module transmits to the water sample in the U-shaped groove where light absorption, scattering and fluorescence emission occur, wherein the emitted fluorescence goes across the quartz plate C and the band-pass filter and is detected by the fluorescence-detecting photodiode C, while the blue light scattered by particulates and/or colloids passes through the band-pass filter for humic-based fluorescence detection and detected by the fluorescence-detecting photodiode C, and the light that has not been absorbed and scattered by water sample goes across the quartz plate B and reaches the ultraviolet-visible light detecting photodiode B.
4. The multi-parameter water quality monitoring device according to claim 1 , further comprising
a beam splitter, and
a reference light detecting photodiode A.
5. The multi-parameter water quality monitoring device according to claim 4 , wherein the beam splitter is arranged at a 45° angle relative to the central axis of the composite LED module.
6. The multi-parameter water quality monitoring device according to claim 4 , wherein the beam splitter splits a light beam from the composite LED module into two beams at an optical power ratio ranging from 10/90 to 90/10.
7. The multi-parameter water quality monitoring device according to claim 4 , wherein the central axis of the composite LED module is arranged perpendicular to the central axis of the U-shaped groove, and the central axis of the reference light detecting photodiode A is arranged perpendicular to that of the composite LED module.
8. The multi-parameter water quality monitoring device according to claim 4 , wherein the central axis of the composite LED module is arranged in parallel to the central axis of the U-shaped groove, and the central axis of the reference light-detecting photodiode A is arranged in parallel to that of the composite LED module.
9. The multi-parameter water quality monitoring device according to claim 3 , further comprising a reflector for reflecting a light to the ultraviolet-visible light-detecting photodiode B.
10. The multi-parameter water quality monitoring device according to claim 1 , wherein the reference light detecting photodiode A and the ultraviolet-visible light detecting photodiode B are UV enhanced silicon photodiodes or composite photodiodes each packaged with an AlGaN based deep-ultraviolet light detecting chip and a silicon photovoltaic plate.
11. The multi-parameter water quality monitoring device according to claim 10 , wherein the silicon photovoltaic plate is -shaped and the AlGaN based deep-ultraviolet light-detecting chip is in the groove part of the -shaped silicon photovoltaic plate.
12. The multi-parameter water quality monitoring device according to claim 1 , wherein the band-pass filter is (a) a band-pass filter covering 320-360 nm for detection of protein-based fluorescence, (b) a band-pass filter covering 380-500 nm for detection of humic-based fluorescence, or (c) a band-pass filter covering 320-500 nm for detection of the total fluorescence from both proteins and humic substances.
13. A multi-parameter water quality monitoring probe, comprising
a casing,
an optical detection unit, and
an electronic circuit unit, wherein the optical detection unit comprises the multi-parameter water quality monitoring device according to claim 1 .
14. The multi-parameter water quality monitoring probe according to claim 13 , wherein the casing comprises
a U-shaped front cover, configured to receive and fix the optical detection unit,
a cylinder, configured to receive the electronic circuit unit,
a back cover, configured to fix a power cable in a water-tight way.
15. The multi-parameter water quality monitoring probe according to claim 13 , wherein the electronic circuit unit comprises a microcontroller, a power supply module, a signal amplification circuit, an analog-to-digital converter, a communication module, and a temperature sensor.