CN109425409A - A kind of photoelectric liquid-levle measuring device and method - Google Patents
A kind of photoelectric liquid-levle measuring device and method Download PDFInfo
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- CN109425409A CN109425409A CN201810849689.3A CN201810849689A CN109425409A CN 109425409 A CN109425409 A CN 109425409A CN 201810849689 A CN201810849689 A CN 201810849689A CN 109425409 A CN109425409 A CN 109425409A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
- G01F23/28—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
- G01F23/284—Electromagnetic waves
- G01F23/292—Light, e.g. infrared or ultraviolet
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Abstract
The invention discloses a kind of photoelectric liquid-levle measuring devices of high discrimination, belong to photoelectric detection technology field, it includes light guide plate, light source and oblique coupled lens, light source is laser, light guide plate is used for and the liquid phase face contact of liquid level to be measured or is disposed adjacent, light guide plate is solid entirety, energy light transmission, light guide plate liquid level face is used for and the liquid phase face contact of liquid level to be measured or is disposed adjacent, and testing liquid liquid level line is fallen in light guide plate liquid level face, guide-lighting micro-structure is provided at light guide plate lighting surface, guide-lighting micro-structure has compared with strong scattering effect light beam, and light can be effectively destroyed in the total reflection of light guide plate lighting surface, the light guide plate plane of incidence for laser light source for entering to inject light guide plate, there is photo absorption performance at light guide plate exit facet or be provided with translucent construction, oblique coupled lens are incident to for making laser light source with the angle set In light guide plate.Measuring device structure of the present invention is simple, and process is distinguished obviously, and component is cheap, and measurement is accurate reliable, easy to maintain.
Description
Technical field
The invention belongs to photoelectric detection technology fields, and in particular to a kind of liquid level survey of photo-electric high-precision strong interference immunity
Measure method and device.
Background technique
Level gauging is prepared in biology, chemical process, is had in the fields such as fuel monitoring and is widely applied very much, existing liquid level
Measuring system mainly includes condenser type, ultrasonic type and optical fiber type by principle classification.
The basic principle of capacitance liquid level measuring system are as follows: the filling liquid cognition between two electrode of capacitor causes capacitor to change,
Liquid level height can be obtained by the capacitance size that liquid capacitor is immersed in measurement.Capacitance liquid level measurement application has biggish limitation
Property, there is measurement vulnerable to electromagnetic interference, it is necessary to capacitor be immersed in liquid and measured, measuring device is easily corroded, and is unable to measure easily
The disadvantages of firing explosive liquid.
Ultrasonic liquid level measuring measures liquid using the time of ultrasonic sensor detection liquid surface reflection echo transmission
Position, since the spread speed of sound wave is very fast, and other than liquid surface, there is also other reflection echos, so, ultrasonic wave
Level gauging is difficult to realize high-accuracy stable level gauging.And the velocity of sound is by density, pressure, the influence of the factors such as temperature, Wu Fashi
Answer changeable environment.
In recent years, with the fast development of fibre optical sensor, application of the optical fiber in level gauging field is also more and more popular,
Effective refractive index changes to detect liquid level when optical fiber type level gauging is by immersing liquid for special fiber, such as using various
Effective refractive index change causes fiber bragg grating center wavelength drift to measure liquid level to fiber grating in a liquid, although optical fiber liquid level
Level measuring method before measurement is compared has certain advantage, such as can measure flammable and combustible liquids, electromagnetism interference, but goes back
Be that there are some disadvantages, must such as immerse liquid measure, it is difficult to adapt to different refractivity liquid, need spectrometer cause cost compared with
It is high, it has not been convenient to maintenance etc..
Therefore, it is necessary to develop a kind of novel liquid level detection device or method, it is desirable that its is easy to use, measurement is smart
Really, low in cost, easy to maintain.
Summary of the invention
Aiming at the above defects or improvement requirements of the prior art, the present invention provides a kind of photoelectric liquid-levle measuring device and
Method designs a kind of novel photoelectric liquid-levle measurement dress using light guide plate it is intended that being based on existing optical principle
It sets, structure is simple, and component is cheap, and measurement is accurate reliable, and it is easy to maintain, it is easy-to-use, it can be preferably in engineering reality
Trample middle utilization.
To achieve the above object, according to one aspect of the present invention, the photoelectric liquid-levle for providing a kind of high discrimination is surveyed
Measure device comprising light guide plate, light source and oblique coupled lens, wherein light source is laser,
Light guide plate is used for and the liquid phase face contact of liquid level to be measured or is disposed adjacent, and light guide plate is solid entirety, energy
Light transmission,
There are two relatively parallel face, respectively light guide plate liquid level face and light guide plate lighting surface, light guide plate liquid for light guide plate tool
Plane is used for and the liquid phase face contact of liquid level to be measured or is disposed adjacent, and testing liquid liquid level line falls within light guide plate liquid level
In face, guide-lighting micro-structure is provided at light guide plate lighting surface, guide-lighting micro-structure has compared with strong scattering effect light beam, and can be effective
Destroy light light guide plate lighting surface total reflection,
The light guide plate also has two faces being oppositely arranged, respectively the light guide plate plane of incidence and light guide plate exit facet, leads
The tabula rasa plane of incidence has photo absorption performance for entering to inject light guide plate for laser light source, at light guide plate exit facet or is provided with light transmission
Structure, to guarantee that the light for injecting the light guide plate exit facet is not reflected,
Oblique coupled lens are arranged near the light guide plate plane of incidence, and the angle set for making laser light source is incident to leaded light
In plate, laser beam divergence is small to make most laser all since the cirtical angle of total reflection changes in light guide plate contact liq
It is emitted in liquid.
Further, when work, laser changes light guide plate inner light beam to light guide plate incident beam, by testing liquid liquid level
Transmission, so that most of light beam is reflected feed liquor body at light guide plate liquid level face contact liquid, go out to change light guide plate lighting surface
The light field for penetrating light by detecting the variation of the emergent light light field, and then detects the liquid level for obtaining testing liquid.
Further, the guide-lighting micro-structure is recess or protrusion scattering netted dot or reticle structure, is had to light beam
It is acted on compared with strong scattering, and can effectively destroy light in the total reflection of lighting surface.
Further, the light guide plate material is transparent light guide medium.
Further, the oblique coupled lens are triangular prism.
Further, the light guide plate is cuboid shape, two maximum face is respectively light guide plate liquid level face and leaded light
Plate lighting surface.
Further, the material of the light guide plate is organic glass.
It further, further include optically focused cylindrical lens, the optically focused cylindrical lens setting is located relatively in light guide plate lighting surface, with
For collecting the light field being emitted from light guide plate lighting surface, while being also used to the light beam convergence in lighting surface same horizontal line.
It further, further include optical filter, array photoelectric detector part and signal acquisition process unit, the optical filter
Setting is on optically focused cylindrical lens outgoing light direction, and for filtering out stray light, the array photoelectric detector part is for acquiring from filter
The light with liquid level signal of mating plate outgoing is simultaneously translated into electric signal, and the signal acquisition process unit is for acquiring institute
Electric signal is stated, and analyzes and handles the electric signal to obtain liquid level.
Further, the optically focused cylindrical lens, the optical filter, the array photoelectric detector are respectively provided with multiple, more
A optically focused cylindrical lens, multiple optical filters, multiple array photoelectric detectors are respectively sequentially connected in series, to expand respective range.
The operation principle of the present invention is that:
Light source issues light from the incident light guide plate of upper side (the light guide plate plane of incidence), when guide-lighting back (light guide plate liquid level face)
When contacting with air, light transmits from top to bottom in light guide plate, it is most of light guide plate reverse side (without guide-lighting micro-structure one side,
That is light guide plate liquid level face) be totally reflected, simultaneously because the presence of the positive guide-lighting micro-structure of light guide plate, light from light guide plate just
Face uniform.
When guide-lighting back and liquid contact, since liquid refractivity is larger, light is destroyed in the complete of light guide plate reverse side
Reflection, light can be refracted in liquid from light guide plate liquid level face, lead to the part of contact liq and ingress of air in light guide plate
There is biggish light intensity difference in part, which equally appears in light guide plate positive (namely light guide plate lighting surface) outgoing
In light, front emergent light after collector lens and optical filter by array photoelectric detector part by being received, final data acquisition and place
Reason unit calculates liquid level by detecting emergent light light intensity change location.
In general, through the invention it is contemplated above technical scheme is compared with the prior art, can obtain down and show
Beneficial effect:
Light is propagated in solid interior, not vulnerable to outside environmental elements and liquid surface fluctuation interference；Utilize liquid and sky
The larger carry out level gauging of gas refractive index difference is good to different refractivity liquid applicability；
The guide-lighting back contacted with liquid is an organic glass plane, maintenance convenient for cleaning；
The precision and range of level gauging are only limited to the pixel size of array photoelectric detector part, select suitable array
Photoelectricity testing part can be realized high-precision liquid level measurement；
Liquid level measuring system apparatus structure of the invention is simple, only includes light source, light guide plate, collector lens, optical filter, battle array
Column photoelectricity testing part and signal acquisition process unit, the above device cost are low.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of liquid level emasuring device core component of the present invention；
Fig. 2 is liquid level emasuring device light source described in the embodiment of the present invention from light guide plate left side or the light of right side incidence
Line structure schematic diagram；
Fig. 3 is a kind of structural schematic diagram of liquid level emasuring device practical application of the present invention；
Fig. 4 liquid level emasuring device of the present invention uses a kind of example structure schematic diagram of laser light source；
Fig. 5 is a kind of structural schematic diagram of liquid level emasuring device expanded range of the present invention.
Specific embodiment
In order to make the objectives, technical solutions, and advantages of the present invention clearer, with reference to the accompanying drawings and embodiments, right
The present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, and
It is not used in the restriction present invention.As long as in addition, technical characteristic involved in the various embodiments of the present invention described below
Not constituting a conflict with each other can be combined with each other.
The present invention provides a kind of photoelectric liquid-levle measuring device comprising light guide plate, light guide plate are used for and liquid level to be measured
Liquid phase face contact or be disposed adjacent, light guide plate is solid entirety, can light transmission, light guide plate tool is there are two relatively parallel
Face, respectively light guide plate liquid level face and light guide plate lighting surface, light guide plate liquid level face are used to practise physiognomy with the liquid of liquid level to be measured and connect
It touches or is disposed adjacent, and testing liquid liquid level line is fallen in light guide plate liquid level face, be provided at light guide plate lighting surface guide-lighting micro-
Structure, for being different from outside the light-output to light guide plate of the transmission in light guide plate light guide plate liquid level face and being different from leaded light
The place of plate lighting surface is changed the transmission of light guide plate inner light beam by testing liquid liquid level, makes leaded light to light guide plate incident beam
A part of light beam is not totally reflected in plate, to change the light field of light guide plate lighting surface emergent light, by detecting the outgoing
The variation of light light field, and then detect the liquid level for obtaining testing liquid.Light guide plate also has two faces being oppositely arranged, and respectively leads
The tabula rasa plane of incidence and light guide plate exit facet, for entering to inject light guide plate for extraneous measuring beam, light guide plate goes out the light guide plate plane of incidence
Penetrating at face has photo absorption performance or is provided with translucent construction, to guarantee that the light for injecting the light guide plate exit facet is not reflected.
Wherein, guide-lighting micro-structure is the recess perhaps scattering netted dot of overshooting shape or be reticle structure, is had to light beam
It is acted on compared with strong scattering, and can effectively destroy light in the total reflection of lighting surface.Light guide plate material can be transparent light guide medium.
In Practical Project, photoelectric liquid-levle measuring device of the invention further includes light source, optically focused cylindrical lens, optical filter, battle array
Column photoelectricity testing part and signal acquisition process unit, optically focused cylindrical lens setting are located light guide plate lighting surface is opposite, with
In the light field that collection is emitted from light guide plate lighting surface, it is also used to the light beam convergence in lighting surface same horizontal line.Optical filter is set
It sets on optically focused cylindrical lens outgoing light direction, for filtering out stray light, the array photoelectric detector part is for acquiring from optical filtering
The light with liquid level signal of piece outgoing is simultaneously translated into electric signal, and the signal acquisition process unit is described for acquiring
Electric signal, and analyze and handle the electric signal to obtain liquid level.
In use, light source, for being incident in light guide plate by the light guide plate plane of incidence, the light source is point light source, linear light source
Or area source.
In one embodiment of the invention, light guide plate is cuboid shape, two maximum face is respectively light guide plate liquid
Plane and light guide plate lighting surface.The material of light guide plate is organic glass or optical glass.
Have in one embodiment in of the invention, the optically focused cylindrical lens, the optical filter, the array photoelectric detector
It is respectively provided with multiple, multiple optically focused cylindrical lens, multiple optical filters, multiple array photoelectric detectors are respectively sequentially connected in series, to expand
Big respective range.
As shown in FIG. 1, FIG. 1 is the structures of liquid level emasuring device core component of the present invention for the embodiment of the present invention 1
Schematic diagram, the selection of light source 3 have the light source (such as LED light source) of certain angle of divergence, and the light that light source issues enters from 1 side of light guide plate
It penetrates, 1 reverse side of light guide plate (left side in Fig. 1) contact measured liquid, front (right side in Fig. 1) has surface micro-structure 2 to export light guide plate 1
When interior light, 1 reverse side of light guide plate and air contact, light transmits from top to bottom in light guide plate, most of in light guide plate reverse side
It is totally reflected, simultaneously because there is the guide-lighting micro-structure of specific configuration rule in light guide plate front, (guide-lighting micro-structure is also referred to as surface
Micro-structure 2) presence, light is from light guide plate front uniform.
When 1 reverse side of light guide plate and liquid contact, light is destroyed since liquid refractivity is larger in light guide plate liquid level face
It is totally reflected, most of light in light guide plate liquid level face contact liquid portion can be refracted in liquid, optical transport in light guide plate
Loss is significantly increased, and the part of contact liq and the part of ingress of air in light guide plate 1 is caused to have biggish light intensity difference, guide-lighting
Light intensity can acutely decline in liquid level position in plate, which equally appears in the emergent light of light guide plate front, just
Face emergent light after optically focused cylindrical lens 4 and optical filter 5 by array light-intensity test device 6 by being acquired, final data acquisition and processing
Unit 7 calculates liquid level position by the position of detection light intensity variation.
The embodiment of the present invention 2 is as shown in Fig. 2, Fig. 2 is liquid level emasuring device light source described in the embodiment of the present invention from leaded light
The light channel structure schematic diagram of plate left side or right side incidence, embodiment 2 are the present invention feasible reality a kind of in actual measurement
Apply example.
The embodiment of the present invention 3 is as shown in figure 3, Fig. 3 is a kind of structure of liquid level emasuring device practical application of the present invention
Schematic diagram, embodiment 3 added container 8 and fluid connection pipe 9, light guide plate 1 and container 8 on the basis of the embodiment of the present invention 1
The container of a splendid attire testing liquid is collectively formed, fluid connection pipe 9 is arranged at 8 bottom of level gauging container, can be by fluid connection
Pipe 9 is connected to the primary tank for containing liquid, so that liquid level communicates in the container 8 of primary tank and level gauging, by measuring liquid level
Liquid level in measurement container 8 can measure the liquid level in testing container.
The embodiment of the present invention 3 i.e. as shown in figure 3, with the embodiment of the present invention 1 the difference is that: light source changes uniform array into
Light source 3 is scattered, and is injected from light guide plate left side or right side, the advantages of embodiment 3 is uniform array light source 3 from side
Incidence, scattering micro-structural 2 need light guide plates front when uniformly light guide plate reverse side ingress of air can be realized in arrangement on light guide plate
Uniformly go out light in vertical direction, and higher compared to 1 uniformity of embodiment.Meanwhile light meeting before reaching array photodetectors
A distance is first transmitted, in liquid level face contact liquid, intensity loss is larger in light guide plate, so optical transport a distance can be led
Cause light intensity sharp fall；And in liquid level face contact air, smaller, the damage of optical transport a distance is lost in light guide plate inner light beam
Consumption is smaller, so the light intensity boundary of array photodetectors detect at this time liquid and air part is more obvious, it is easier to
Distinguish liquid and air.
The embodiment of the present invention 4 is as shown in figure 4, Fig. 4 liquid level emasuring device of the present invention uses a kind of reality of laser light source
Apply a structural schematic diagram, with the embodiment of the present invention 1 the difference is that: light source changes the lesser laser of the angle of divergence into, and in leaded light
Plate side makes laser incident light guide plate 1 at an angle plus oblique coupled lens 10, due to laser beam divergence very little, in leaded light
Overwhelming majority laser can be all emitted in liquid at once when plate contact liq, so the light intensity variation near the liquid level in light guide plate
More acutely, the liquid and air of light guide plate reverse side have more obvious discrimination.
More specifically, a kind of photoelectric liquid-levle measuring device of high discrimination is provided in Fig. 4 device comprising guide-lighting
Plate, light source and oblique coupled lens, wherein light source is laser, light guide plate be used for the liquid phase face contact of liquid level to be measured or
It is disposed adjacent, light guide plate is solid entirety, and energy light transmission, there are two relatively parallel faces, respectively light guide plate liquid level for light guide plate tool
Face and light guide plate lighting surface, light guide plate liquid level face are used for and the liquid phase face contact of liquid level to be measured or are disposed adjacent, and to
It surveys liquid level line to fall in light guide plate liquid level face, guide-lighting micro-structure is provided at light guide plate lighting surface, guide-lighting micro-structure is to light
Beam has compared with strong scattering effect, and can effectively destroy light in the total reflection of light guide plate lighting surface,
Light guide plate also has two faces being oppositely arranged, respectively the light guide plate plane of incidence and light guide plate exit facet, light guide plate
The plane of incidence has photo absorption performance for entering to inject light guide plate for laser light source, at light guide plate exit facet or is provided with light transmission knot
Structure, to guarantee that the light for injecting the light guide plate exit facet is not reflected, oblique coupled lens are arranged near the light guide plate plane of incidence, use
Be incident in light guide plate in making laser light source with the angle set, laser beam divergence it is small in light guide plate contact liq due to
The cirtical angle of total reflection changes and is emitted to most laser all in liquid.It further includes optically focused cylindrical lens, optical filter, array
Photoelectricity testing part and signal acquisition process unit, the optically focused cylindrical lens setting is at the opposite place of light guide plate lighting surface, to be used for
The light field being emitted from light guide plate lighting surface is collected, while being also used to the light beam convergence in lighting surface same horizontal line.The filter
Mating plate setting is on optically focused cylindrical lens outgoing light direction, and for filtering out stray light, the array photoelectric detector part is for acquiring
From optical filter be emitted the light with liquid level signal and be translated into electric signal, the signal acquisition process unit be used for adopt
Collect the electric signal, and analyzes and handle the electric signal to obtain liquid level.In the embodiment of Fig. 4, the oblique coupled lens are
Triangular prism.
Further, when work, laser changes light guide plate inner light beam to light guide plate incident beam, by testing liquid liquid level
Transmission, so that most of light beam is reflected feed liquor body at light guide plate liquid level face contact liquid, go out to change light guide plate lighting surface
The light field for penetrating light by detecting the variation of the emergent light light field, and then detects the liquid level for obtaining testing liquid.
Extension for Fig. 4 embodiment, the optically focused cylindrical lens, the optical filter, array photoelectric detector difference
With multiple, multiple optically focused cylindrical lens, multiple optical filters, multiple array photoelectric detectors are respectively sequentially connected in series, each to expand
From range.
The embodiment of the present invention 5 is as shown in figure 5, Fig. 5 is a kind of structure of liquid level emasuring device expanded range of the present invention
Schematic diagram, embodiment 5 provide a kind of method of expanded range, and the range of liquid level emasuring device depends on array light in the present invention
The range of electric explorer part can be saturating by increasing optical filter and column when the range of single array photodetectors part is inadequate
Mirror carrys out expanded range, and the quantity of optical filter 5 and array photoelectric part 6 carrys out range extension, and it is saturating that 2 columns are shown only in Fig. 5
The structural schematic diagram of 4,2 optical filter 5 and 2 array photoelectrics 6 of mirror can increase more array photoelectric parts
Further expand range.
In the present invention, guide-lighting micro-structure is also referred to as surface micro-structure, is used to destroy light guide plate lighting surface and is totally reflected and dissipates
Lighting surface uniformly goes out light when irradiating light beam makes liquid level face anhydrous.Its specific structure can be recess or protrusion scattering netted dot,
Reticle structure.Laser engraving, chemical attack, injection molding, and internal diffusion way can be used to prepare such micro-structure.
Heretofore described liquid level emasuring device specific workflow is as follows:
Firstly, measuring the light intensity curve of array photoelectric device and preservation in unglazed situation, it is regarded as dark current noise,
During subsequent level gauging, the dark current noise is all first subtracted after reading light intensity curve, to prevent dark current noise pair
The influence of level sensing.
Then, carry out level gauging after opening light source, when level gauging can high speed repeatedly read same liquid level array light
The light intensity curve of electrical part simultaneously carries out signal averaging processing, for reducing dissipating in array photoelectric detector part and its driving circuit
The influence of grain noise, increases the accuracy of level gauging.
Then, liquid level is calculated after obtaining the light intensity comprising liquid level information, there are two ways to liquid level calculates, calculus of finite differences and threshold
Value method.
Calculus of finite differences is that the light intensity that the pixel light intensity of entire light intensity curve is subtracted previous position pixel (can also take opposite direction
Calculus of differences), obtaining a length is the difference curve that array photoelectric device vertical direction pixel quantity subtracts one, and difference is bent
The maximum location of pixels of line (the smallest location of pixels when backward difference) is liquid level position.Due to the presence of noise, a scale
Component curve reliability is lower, can increase difference order suitably to improve the reliability of liquid level identification.
Threshold method is to select suitable Intensity threshold, and first light intensity is lower than the threshold to array photoelectric part from top to bottom
The pixel position of value is liquid level position.
In addition, light guide plate is very important a part in LCD backlight mould group, using than wide, acting on is
Uniform area light source is converted by linear light source.The effect of guide-lighting micro-structure is broken beam being all-trans in light guide plate on light guide plate
It penetrates, the material of light guide plate largely uses acrylic (PMMA), is the material for being most suitable for doing light guide plate at present.Guide-lighting micro-structure is normal
It is recess site, sunk shape is uncertain, has spherical shape, V flute profile or other irregular shapes, also has seldom
Protrusion site is the micro-structure that can effectively destroy the total reflection of light guide plate light beam in a word.The shape one of light guide board microstructure
As it is inessential, the scattering of light is influenced less, so design processing generally thinks little of shape, is largely processed as similar to hemisphere
Irregular shape, determine to the scattering process size of light be micro-structure size.It, can be with when light guide plate side light incidence
Design the closeness of microstructure size or micro-structure according to certain rules to realize that light guide plate front uniformly goes out light.The micro- knot of light guide plate
The mode of processing mainly has: laser engraving, chemical etching, injection molding and internal diffusion.Wherein, laser engraving is with the obvious advantage,
Most light guide plates are all rapid laser carvings.
In the present invention, need to be accomplished that no site one side in the application of display backlight uniformly goes out light, is being applied to
When inside level gauging, due to being inconvenient for the direct contact liq of guide-lighting micro-structure, so needing to realize has site one side uniform
Light out has redesigned light guide plate arrangement rule thus and has been applied in level gauging.
In the present invention, from the device of left side or right side incident light, due in same vertical line with light source distance one
Sample, so not needing to design special micro-structure arrangement rule, uniform-dimension is uniformly arranged.Light is incident from different perspectives to be needed
Accordingly design different micro-structure arrangements.So scheme should be different from upper side incidence and from left (right side) side incidence.
In addition, not being that whole light can all occur in liquid level face contact air part due to the scattering process of micro-structure yet
Total reflection, it is only more compared to the light that the part of contact liq is totally reflected, so just foring light intensity difference.
As it will be easily appreciated by one skilled in the art that the foregoing is merely illustrative of the preferred embodiments of the present invention, not to
The limitation present invention, any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should all include
Within protection scope of the present invention.
Claims (10)
1. a kind of photoelectric liquid-levle measuring device of high discrimination, which is characterized in that it includes light guide plate, light source and tiltedly couples saturating
Mirror, wherein light source is laser,
Light guide plate is used for and the liquid phase face contact of liquid level to be measured or is disposed adjacent, and light guide plate is solid entirety, can light transmission,
There are two relatively parallel face, respectively light guide plate liquid level face and light guide plate lighting surface, light guide plate liquid level faces for light guide plate tool
For with the liquid phase face contact of liquid level to be measured or be disposed adjacent, and testing liquid liquid level line falls within light guide plate liquid level face
It is interior, guide-lighting micro-structure is provided at light guide plate lighting surface, guide-lighting micro-structure has compared with strong scattering effect light beam, and can effectively break
Bad light light guide plate lighting surface total reflection,
The light guide plate also has two faces being oppositely arranged, respectively the light guide plate plane of incidence and light guide plate exit facet, light guide plate
The plane of incidence has photo absorption performance for entering to inject light guide plate for laser light source, at light guide plate exit facet or is provided with light transmission knot
Structure, to guarantee that the light for injecting the light guide plate exit facet is not reflected,
Oblique coupled lens are arranged near the light guide plate plane of incidence, and the angle set for making laser light source is incident to light guide plate
Interior, laser beam divergence is small to make more laser all be emitted to since the cirtical angle of total reflection changes in light guide plate contact liq
In liquid.
2. a kind of photoelectric liquid-levle measuring device of high discrimination as described in claim 1, which is characterized in that when work, swash
Light is changed the transmission of light guide plate inner light beam by testing liquid liquid level, made compared with multiple beam in light guide plate to light guide plate incident beam
Feed liquor body is reflected at liquid level face contact liquid, to change the light field of light guide plate lighting surface emergent light, by detecting the emergent light
The variation of light field, and then detect the liquid level for obtaining testing liquid.
3. a kind of photoelectric liquid-levle measuring device of high discrimination as claimed in claim 2, which is characterized in that the leaded light is micro-
Structure is recess or protrusion scattering netted dot or reticle structure, is had light beam compared with strong scattering effect, and can effectively destroy
Total reflection of the light in lighting surface.
4. a kind of photoelectric liquid-levle measuring device of high discrimination as claimed in claim 3, which is characterized in that the light guide plate
Material is transparent light guide medium.
5. a kind of photoelectric liquid-levle measuring device of high discrimination as claimed in claim 4, which is characterized in that the oblique coupling
Lens are triangular prism.
6. a kind of photoelectric liquid-levle measuring device of high discrimination as claimed in claim 5, which is characterized in that the light guide plate
For cuboid shape, two maximum face is respectively light guide plate liquid level face and light guide plate lighting surface.
7. a kind of photoelectric liquid-levle measuring device of high discrimination as claimed in claim 6, which is characterized in that the light guide plate
Material be organic glass.
8. a kind of photoelectric liquid-levle measuring device of high discrimination as claimed in claim 7, which is characterized in that it further includes gathering
Light beam lens, the optically focused cylindrical lens setting is at the opposite place of light guide plate lighting surface, to be emitted for collecting from light guide plate lighting surface
Light field, while be also used to by lighting surface same horizontal line light beam convergence.
9. a kind of photoelectric liquid-levle measuring device of high discrimination as claimed in claim 8, which is characterized in that it further includes filter
Mating plate, array photoelectric detector part and signal acquisition process unit, the optical filter setting are emitted light direction in optically focused cylindrical lens
On, for filtering out stray light, the array photoelectric detector part is used to acquire the light with liquid level signal being emitted from optical filter
Line is simultaneously translated into electric signal, and the signal acquisition process unit is analyzed for acquiring the electric signal and handles the telecommunications
Number to obtain liquid level.
10. a kind of photoelectric liquid-levle measuring device of high discrimination as claimed in claim 9, which is characterized in that the optically focused
Cylindrical lens, the optical filter, the array photoelectric detector be respectively provided with it is multiple, it is multiple optically focused cylindrical lens, multiple optical filters, more
A array photoelectric detector is respectively sequentially connected in series, to expand respective range.
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