CN109931965A - Optical encoder - Google Patents
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- CN109931965A CN109931965A CN201711430809.8A CN201711430809A CN109931965A CN 109931965 A CN109931965 A CN 109931965A CN 201711430809 A CN201711430809 A CN 201711430809A CN 109931965 A CN109931965 A CN 109931965A
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Abstract
The present invention discloses a kind of optical encoder, and it includes light source module, device for testing light, coding disk, the first optical lens group and the second optical lens groups.Light source module is to issue light beam.Device for testing light is to receive light beam.Coding disk is between light source module and device for testing light.First optical lens group is between light source module and coding disk.First optical lens group and light source module keep first distance, and keep second distance with coding disk.Second optical lens group is between coding disk and device for testing light.Second optical lens group and coding disk keep third distance, and keep the 4th distance with device for testing light.First distance, second distance, third distance and the 4th distance meet the definition of symmetrical optical projection principle, to enable the first optical lens group that light beam is focused to coding disk, and enable the second optical lens group that light beam is focused to device for testing light.
Description
Technical field
The present invention relates to a kind of optical encoders, and it is former to meet symmetrical optical projection more particularly to a kind of optical lens group
The optical encoder of reason.
Background technique
The sensing module that encoder is positioned as servo motor is widely used in toolroom machine, robot and semiconductor and sets
It is standby etc..Wherein, the precision of encoder directly influences the positioning performance of mechanical equipment.Global industry comprehensive automation at present
Gesture is driven, it is growing day by day for the demand of servo motor.
Encoder is a kind of information is converted to the sensors of other specific formats, software by a kind of specific format or is drilled
Algorithm, the purpose of conversion may be due to standardization, speed, confidentiality, security personnel or for compressed data.Wherein, rotation is compiled
Code device is the electromechanical assembly that rotation position or rotation amount are converted into analogy or digital signal, can be divided mainly into optics according to construction
Formula encoder and two kinds of mechanical encoder.Also have the disk of a meeting and main shaft synchronous rotary in optical encoder, disk by
Glass or plastic cement are made, wherein there is the transparent and opaque region for being divided into many concentric circles.Have respectively in the two sides of disk
Light source and OPTICAL SENSORS array, the data read can indicate the position of disk, and by the data transmission read to micro process
Device is converted to the position of axis.
Existing optical encoders, angle sensors only 10 microns of every lattice position width, have reached conventional geometric when 24 positioning accuracy
Optical resolving power limit can generate diffraction interference problem.In addition, because of the characteristic of light beam straight ahead, the sensing of device for testing light
The width close-packed arrays that element is also required to 10 microns, no matter therefore having in the production or assembling contraposition of device for testing light sensing array
High degree of difficulty.
In addition, existing optical encoders, angle sensors are to improve energy and use laser light source (Laser Diode, LD), meeting
Leading to encoder, increased production cost and service life is shorter.Also, optical encoders, angle sensors are with laser as light source
When, need to arrange in pairs or groups high-precision photomask manufacture craft production optical encoding disk, could utilize diffraction phenomenon that device for testing light is allowed to receive and compile
Code signal.So encoder can be made to have higher production cost, and then it is low to lead to the problem of production.
Summary of the invention
Optical encoder disclosed in one embodiment of the invention, comprising a light source module, a device for testing light, a coding disk,
One first optical lens group and one second optical lens group.Light source module is to issue a light beam.Device for testing light is to receive light
Beam.Coding disk is between light source module and device for testing light.First optical lens group is between light source module and coding disk.First
Optical lens group and light source module keep a first distance, and the first optical lens group and coding disk keep a second distance.The
Two optical lens groups are between coding disk and device for testing light.Second optical lens group and coding disk one third distance of holding, and the
Two optical lens groups and device for testing light keep one the 4th distance.Wherein, first distance, second distance, third distance and the 4th away from
From the definition for meeting symmetrical optical projection principle, to enable the first optical lens group that the light beam from light source module is focused to volume
Code-disc, and enable the second optical lens group that the light beam for penetrating coding disk is focused to device for testing light.
Optical encoder disclosed in another embodiment of the present invention include a light source module, a coding disk, a device for testing light,
One optical lens group, a reflecting type polarizing element and a polarization spectroscope.Light source module is to issue a light beam.Coding disk position
In on beam path.Device for testing light is to receive the light beam by coding disk.Optical lens group be located at light source module and coding disk it
Between.Optical lens group and light source module keep a first distance, and optical lens group and coding disk keep a second distance.Reflection
Formula polarization element is located at side of the coding disk far from optical lens group, to reflect the light beam by coding disk.Polarization spectroscope
Between light source module and optical lens group.Polarization spectroscope and optical lens group keep one the 5th distance, and polarization spectro
Mirror and device for testing light keep one the 6th distance.Wherein, the sum total of the 5th distance and the 6th distance length is equal to first distance, and first
Distance, second distance, the 5th distance meet the definition of symmetrical optical projection principle with the 6th distance, to enable optical lens group will
It from light source module and penetrates the light beam after polarization spectroscope and focuses to coding disk, and will be reflected back by reflecting type polarizing element
Light beam focuses to polarization spectroscope, then light beam is reflexed to device for testing light by polarization spectroscope.
The optical encoder according to above-described embodiment makes light beam by the function of optical lens group converging beam
It focuses on coding disk with by width only 6~10 microns of grating, and the light focusing that will be dissipated by coding disk is to examining
Light device, by symmetrical optical projection principle, lens design be specifically imaged receive optical position, enable coding after light beam with compared with
Big width spacing is irradiated in device for testing light.In this way, the sensing unit on device for testing light can have it is looser be arranged, make its with
The aligning accuracy demand of coding disk reduces.The resolution obstacle that conventional codec encodes high precision position can be broken through as a result, together
When can also reduce aligning accuracy.In addition, focusing the light beam on coding disk by way of optically focused, make to be irradiated on device for testing light
Light beam has biggish energy, thus the encoded signal for being irradiated in device for testing light can be made to be more clear, and then has more preferably signal
Noise ratio.
The explanation of explanation and following implementation above with respect to the content of present invention is to demonstrate and explain original of the invention
Reason, and claim of the invention is provided and is further explained.
Detailed description of the invention
Fig. 1 is the schematic side view of optical encoder described in the first embodiment of the present invention；
Fig. 2 is the partial elevational schematic diagram of the coding disk of Fig. 1；
Fig. 3 is the device for testing light of Fig. 1 and the partial enlargement diagram of the absolute encoding pattern on coding disk；
Fig. 4 A~Fig. 4 C is that the device for testing light of Fig. 1 and the partial enlargement of the thin partition type coding pattern on coding disk and actuation are shown
It is intended to；
Fig. 5 is the schematic side view of optical encoder described in the second embodiment of the present invention；
Fig. 6 is the schematic side view of optical encoder described in the third embodiment of the present invention；
Fig. 7 is the schematic side view of optical encoder described in the fourth embodiment of the present invention.
Symbol description
1,1a, 1b, 1c optical encoder
10,10a, 10b, 10c light source module
20,20a, 20b, 20c device for testing light
21 sensing elements
30,30c sensing circuit
40,40a, 40b, 40c coding disk
41 transparent areas
43, the opaque area 43c
The reflective areas 45c
50, the first optical lens group of 50a, 50b
51, the first lens of 50a
53 second lens
The first lens of 55b
The second lens of 57b
59b the third lens
60, the second optical lens group of 60a, 60b
61, the first lens of 60a
63 second lens
The first lens of 65b
The second lens of 67b
69b the third lens
70c optical lens group
The first lens of 71c
The second lens of 73c
80c polarization spectroscope
90c reflecting type polarizing element
L, Lc light beam
W width
D1, D1a, D1b, D1c first distance
D2, D2a, D2b, D2c second distance
D3, D3a, D3b third distance
The 4th distance of D4, D4a, D4b
The 5th distance of D5c
The 6th distance of D6c
Specific embodiment
The detailed features and advantage of narration the embodiment of the present invention, content are enough to make in detail in embodiments below
Have usual skill in any this field to understand the technology contents of the embodiment of the present invention and implement accordingly, and according to this specification
Disclosure of that, claim and schema, having usual skill in any this field, can be readily understood upon the present invention relevant
Purpose and advantage.The embodiment below viewpoint that present invention be described in more detail, but it is non-of the invention anyways to limit
Scope.
Fig. 1 and Fig. 2 is please referred to, Fig. 1 is that the side view of the optical encoder according to the first embodiment of the present invention is illustrated
Figure, and Fig. 2 is the partial elevational schematic diagram of the coding disk of Fig. 1.
The optical encoder 1 of the present embodiment includes light source module 10, device for testing light 20, sensing circuit 30, coding disk 40, first
Optical lens group 50 and the second optical lens group 60.
In the present embodiment, light source module 10 is micro-led array (Micro LED array), to issue
For the light beam L of strip light field.Micro-led benefit used by the present embodiment light source module 10 can allow for it
2 microns of line width or more photomask manufacture craft production optical encoding disk, compared to laser diode (Laser Diode,
LD) and its high-precision photomask (precision is about 0.25 micron) that need to arrange in pairs or groups, micro-led and taken to make with it
The photomask lower production costs for the optical encoding disk matched.In addition, micro-led service life is generally compared with laser two
Pole pipe is long.That is, compared to laser diode, the micro-led characteristic with high production and high durability.
However, being not intended to limit the invention with micro-led for the feature of light source.In other embodiments, light source module
Light emitting diode (LED) can be used according to actual demand.
20 facing light sources module 10 of device for testing light and set, to receive light source module 10 sending light beam L.In the present embodiment
In, device for testing light 20 is made of multiple sensing elements 21, and sensing element 21 is light sensitive diode (Photodiode, PD), but
Invention is not limited thereto.In other embodiments, device for testing light can be for sensing array module or by multiple sensing array modules institute
Composition；In addition, sensing element 21 can also be avalanche-type light sensitive diode (Avalanche Photodiode, APD).
Sensing circuit 30 connects device for testing light 20, the signal spread out of to differentiate device for testing light 20.
For coding disk 40 between light source module 10 and device for testing light 20,40 center of coding disk may connect to motor (not being painted)
Shaft (not being painted), for by motor (not being painted) drive coding disk 40 rotate.
First optical lens group 50 is between light source module 10 and coding disk 40.First optical lens group 50 includes first
Lens 51 and the second lens 53, and the second lens 53 compared with the first lens 51 close to coding disk 40.First optical lens group 50 with
Light source module 10 keeps first distance D1, and the first optical lens group 50 keeps second distance D2 with coding disk 40.
Second optical lens group 60 is between coding disk 40 and device for testing light 20.Second optical lens group 60 includes first saturating
Mirror 61 and the second lens 63, and the second lens 63 compared with the first lens 61 close to coding disk 40.Second optical lens group 60 and volume
Code-disc 40 keeps third distance D3, and the second optical lens group 60 keeps the 4th distance D4 with device for testing light 20.
It please cooperate referring to following table one, be first and second optical lens group 50,60 of the present embodiment in an example, each lens
Optical parameter list.
In the present embodiment, first distance D1 is equal to the 4th distance D4, and second distance D2 is equal to third distance D3, and first
Distance D1 is different from second distance D2.In this way, first distance D1, second distance D2, third distance D3 and the 4th distance D4 symbol
Close the definition of symmetrical optical projection principle.By the function of 60 optically focused of the first optical lens group 50 and the second optical lens group,
Only there are such as 10 to 40 microns wide gratings to enable the first optical lens group 50 focus to the light beam L from light source module 10
Coding disk 40 on, and enable the second optical lens group 60 that will penetrate coding disk 40 and the light beam L that dissipates is with wide compared with 10 to 40 microns
Big spacing is spent to focus on device for testing light 20.What the sensing element 21 on device for testing light 20 can be looser as a result, is arranged, and makes
The aligning accuracy demand of itself and coding disk 40 reduces.In addition, light beam L is focused on coding disk 40 by way of optically focused, phase
Compared in a manner of parallel light projection, the present embodiment is irradiated in the light beam L on device for testing light 20 with biggish energy, thus can make
The encoded signal for being irradiated in device for testing light 20 is more clear, and then has more preferably signal noise ratio.
Above-mentioned first optical lens group 50 and the second optical lens group 60 and light source module 10, coding disk 40 and device for testing light 20
Between the relationship of distance (that is, first distance D1, second distance D2, third distance D3 and the 4th distance D4) be not limited to this
Invention.In other embodiments, under the premise of meeting the definition of symmetrical optical projection principle, first distance, second distance,
Third distance and the 4th distance can be all equal, or in other embodiments, and first distance is equal to second distance, third distance etc.
In the 4th distance, and first distance can be different from third distance.
In the present embodiment, coding disk 40 includes absolute encoding pattern and thin partition type coding pattern.Specifically, it asks
Referring to Fig.2, coding disk 40 includes multiple transparent areas 41 and multiple opaque areas 43, these transparent areas 41 and opaque area 43
Shape is all essentially quadrangle, and arrangement interlaced with each other and form coding pattern.Described is essentially quadrangle, by transparent area
41 and opaque area 43 be considered as straight line in tangential direction for the side of arc, with straight line in the radial direction when surrounding four jointly
The region of shape.
Referring to Fig. 3, for the device for testing light of Fig. 1 and the partial enlargement diagram of the absolute encoding pattern on coding disk.Absolutely
The shape of transparent area 41 and opaque area 43 to formula coding pattern is all rectangle, and width W may be, for example, 10 microns.In this reality
It applies in example, absolute encoding pattern shows 14 coding patterns along the field orientation of strip shaped light beam L, and cooperates on device for testing light 20
14 sensing elements 21, pass through the specific coding permutations mode of transparent area 41 and opaque area 43, it is possible to provide 14 optics
Positioning accuracy.Wherein, absolute encoding pattern may be, for example, that binary code decimal number (Binary-Coded Decimal, BCD) is compiled
The coding modes such as code or Gray code (Gray code), but not limited to this.In the present embodiment, the coding on the direction light beam L
The quantity of pattern is that 14 features are not intended to limit the invention.In other embodiments, the code pattern on beam direction
The quantity of case can increase and decrease according to actual demand.
Fig. 4 A to Fig. 4 C is please referred to, is the device for testing light of Fig. 1 and the partial enlargement of the thin partition type coding pattern on coding disk
And illustrative view.The transparent area 41 of thin partition type coding pattern and the shape in opaque area 43 are all parallelogram and each other
It is staggered, code width W may be, for example, 10 microns.When coding disk 40 rotates, since the shape of transparent area 41 is parallel
Quadrangle, the light beam L being irradiated on coding disk 40 can only segment beam L penetrates same transparent area 41 and exposes in the same time
(1 sensing element 21 is denoted as in such as Fig. 4 A~Fig. 4 C) on several sensing elements 21 of the device for testing light 20 at 40 rear of coding disk,
And the light beam L of another part is then blocked by opaque area 43.As shown in Figure 4 A, local magnification region's schematic diagram of this coding disk 40
On, only the sensing element 21 of the top is irradiated by light beam L, remaining sensing element 21 (is denoted as 0 sensing element in such as Fig. 4 A
21) light beam L is not then sensed due to the position corresponding light beam L is blocked by opaque area 43.With the rotation of coding disk 40, at certain
One moment is as shown in Figure 4 B, and in this region, whole light beam L is not affected by blocking for opaque area 43, makes the sense that rear is all
Element 21 is surveyed all to be irradiated by light beam L.Then, as shown in Figure 4 C at another moment with the lasting rotation of coding disk 40, in this region
Middle light beam L is blocked by opaque area 43 since the top, makes the sensing element 21 of the top (as being denoted as 0 in Fig. 4 C
Sensing element 21) it is not irradiated by light beam.In this way, multiple sensing elements 21 on device for testing light 20 can have section senses in the same time
Element 21 senses light beam L, and section senses element 21 is not sensed by light beam L.Moving and have not with coding disk 40 as a result,
Sensing element 21 with quantity senses light beam L, and it is distinguishable go out different location, reach preferable resolving accuracy.In addition, subdivision
Cutting formula coding also can allow the energy difference that adjacent two sensing elements 21 of resolution sense light beam L, for telling the position of multiple
Precision is set, the use number of sensing element 21 can also be reduced.
Specifically, in thin partition type coded portion, when the sensing element 21 of device for testing light 20 can sense the energy of light beam L
When difference and quantity are up to 1024, it is possible to provide the signal resolution of 10 (bits), and in absolute encoding part, light of arranging in pairs or groups
When 10 original of source module provides for example, 14 optical alignment resolution ratio, so that optical encoder 1 can reach 24 resolutions
Rate.In the present embodiment, coding pattern is cut by the subdivision on above-mentioned Fig. 4 A~Fig. 4 C code disk, by differentiating adjacent two senses
Survey the energy difference that element 21 senses light beam L, the position precision of distinguishable multiple out.For example, when sensing element 21 can be felt
When should and differentiate its lighting area and corresponding light energy size, for example, the distinguishable light energy being irradiated to be 100% or
50% etc., under the sensing element 21 that device for testing light 20 has identical quantity, the position precision of distinguishable more high magnification numbe out.In this way,
The quantity of the sensing element 21 of device for testing light 20 can be reduced to 512 by 1024, or even to 256, still can equally provide 10
The signal resolution of position.
In the present embodiment, first and second optical lens group 50 and 60 the first lens 51 and the first lens 61 all to be convex
Lens, and its second lens 53 and the second lens 63 are all concavees lens, but invention is not limited thereto.In other embodiments,
First lens and the second lens can be separately designed according to actual demand as concavees lens or convex lens.In addition, in the present embodiment, the
The feature that the quantity for the lens that one optical lens group 50 and the second optical lens group 60 respectively include is two is non-to limit the present invention.
In other embodiments, two optical lens groups of optical encoder can include one or three or more lens according to actual demand.
For example, referring to Fig. 5, the side view for the optical encoder according to the second embodiment of the present invention is illustrated
Figure.The present embodiment is similar with first embodiment, and difference is the first optical lens group 50a of the present embodiment optical encoder 1a
And second optical lens group 60a be respectively the first lens 50a and the first lens 60a.In the present embodiment, the first optical lens group
50a and light source module 10a keeps first distance a D1a, the first optical lens group 50a and coding disk 40a to keep a second distance
D2a, the second optical lens group 60a and coding disk 40a keep third distance D3a, and the second optical lens group 60a and device for testing light
20a keeps the 4th distance D4a.First distance D1a is equal to the 4th distance D4a, and second distance D2a is equal to third distance D3a, and the
One distance D1a is different from second distance D2a.In this way, the first distance D1a of the present embodiment, second distance D2a, third distance D3a
And the 4th distance D4a meet the definition of symmetrical optical projection principle.
In the present embodiment, the first lens 50a and the first lens 60a of first and second optical lens group 50a and 60a be
For convex lens, but invention is not limited thereto.
It please cooperate referring to following table two, be first and second optical lens group 50a, 60a of the present embodiment in an example, it is each
The optical parameter list of mirror.
It is the schematic side view of the optical encoder according to the third embodiment of the present invention in addition, seeing also Fig. 6.
The present embodiment is similar with first embodiment, and difference is the first optical lens group 50b packet of the present embodiment optical encoder 1b
It is sequentially arranged from light source module 10b toward the direction of coding disk 40b containing the first lens 55b, the second lens 57b and the third lens 59b,
And second optical lens group 60b include the first lens 65b, the second lens 67b and the third lens 69b it is sequentially past from device for testing light 20b
The direction of coding disk 40b arranges.In the present embodiment, the first optical lens group 50b and light source module 10b keeps first distance
D1b, the first optical lens group 50b and coding disk 40b keep second distance D2b, the second optical lens group 60b and coding disk 40b
Third distance D3b is kept, and the second optical lens group 60b and device for testing light 20b keeps the 4th distance D4b.First distance D1b is equal to
4th distance D4b, second distance D2b are equal to third distance D3b, and first distance D1b is different from second distance D2b.In this way, this
First distance D1b, second distance D2b, third distance D3b and the 4th distance D4b of embodiment meet symmetrical optical projection
The definition of principle.
Please cooperate be referring to following table three the present embodiment first and second optical lens group 50b, 60b in an example, respectively
The optical parameter list of lens.
In the present embodiment, the first lens, the second lens of optical lens group and the third lens be sequentially respectively convex lens,
Concavees lens and convex lens, but invention is not limited thereto.In other embodiments, the first lens, the second lens and the third lens
Can according to actual demand and individual design be concavees lens or convex lens.
The various embodiments described above schematically illustrate the optical lens group comprising different number of lenses respectively.Wherein, when each optical lens group
Number of lenses when being a piece of (as described in second embodiment), raster width (i.e. light transmission sector width) demand on coding disk is 8 micro-
Rice.(as in the first embodiment) when the number of lenses of each optical lens group is two panels, the raster width demand on coding disk can
Up to 6 microns.More preferably, the light when the number of lenses of each optical lens group is three pieces (as described in 3rd embodiment), on coding disk
Grid width demand is smaller than 6 microns.The luminous intensity that device for testing light receives can be substantially improved, as a result, to ensure the coding of encoder
Precision meets demand.
Referring to Fig. 7, being the schematic side view of the optical encoder according to the fourth embodiment of the present invention.
The optical encoder 1c of the present embodiment includes light source module 10c, coding disk 40c, device for testing light 20c, sensing circuit
30c, optical lens group 70c, reflecting type polarizing element 90c and polarization spectroscope (Polarized beam splitter,
PBS)80c。
Light source module 10c is to issue the light beam Lc for strip light field.Coding disk 40c is located on the path light beam Lc.Inspection
Light device 20c is to receive the light beam Lc by coding disk 40c.Sensing circuit 30c connection device for testing light 20c, to differentiate device for testing light
The signal that 20c is spread out of.
Optical lens group 70c is between light source module 10c and coding disk 40c.Optical lens group 70c includes the first lens
71c and the second lens 73c, and the second lens 73c compared with the first lens 71c close to coding disk 40c.Optical lens group 70c and light
Source module 10c keeps first distance D1c, and optical lens group 70c and coding disk 40c keeps second distance D2c.
90c sides of the coding disk 40c far from optical lens group 70c of reflecting type polarizing element, to reflect by coding
The light beam Lc of disk 40c.In the present embodiment, reflecting type polarizing element 90c may be, for example, reflective silicon single liquid crystal (LCOS) member
Part, but not limited to this.
Polarization spectroscope 80c is between light source module 10c and optical lens group 70c.In the present embodiment, device for testing light
20c is located at the side of polarization spectroscope 80c between light source module 10c and optical lens group 70c, and but not limited to this.
Polarization spectroscope 80c and optical lens group 70c keep the 5th distance D5c, and polarization spectroscope 80c and device for testing light 20c keeps the
Six distance D6c.Wherein, the sum total of the 5th distance D5c and the 6th distance D6c length is equal to first distance D1c.
In the present embodiment, first distance D1c is different from second distance D2c.In this way, first distance D1c, second distance
D2c, the 5th distance D5c and the 6th distance D6c meet the definition of symmetrical optical projection principle, to enable optical lens group 70c
From light source module 10c and the light beam Lc after polarization spectroscope 80c will be penetrated focus to coding disk 40c, and will by it is reflective partially
The light beam Lc that optical element 90c is reflected back focuses to polarization spectroscope 80c, then is reflexed to light beam Lc by polarization spectroscope 80c
Device for testing light 20c.
Wherein, the polarization spectroscope 80c of the present embodiment can allow the light of a particular polarization to pass through, and by polarization direction
Perpendicular to the light reflection of the particular polarization.In addition, the reflecting type polarizing element 90c of the present embodiment can reflection light simultaneously
The polarization direction for changing light, even if also the polarization direction of reflected light is for example perpendicular to the polarization direction of incident light.It polarizes as a result,
Spectroscope 80c can allow the light beam Lc from light source module 10c to pass through, and can reflect and change partially via reflecting type polarizing element 90c
The light beam Lc in vibration direction.
Between above-mentioned optical lens group 70c and light source module 10c, coding disk 40c and polarization spectroscope 80c, and polarization point
Distance between light microscopic 80c and device for testing light 20c (that is, first distance D1c, second distance D2c, the 5th distance D5c and the 6th distance
D6c relationship) is not intended to limit the invention.In other embodiments, the sum total of the 5th distance and the 6th distance length is equal to
First distance, first distance is equal to second distance, and meets the definition of symmetrical optical projection principle.
The coding disk 40c of the present embodiment and the coding disk 40 of first embodiment are similar, have multiple transparent areas and multiple
Opaque area reaches reflecting type polarizing element 90c to allow the light beam Lc for being irradiated in part on coding disk 40c to pass through transparent area, leads to
It crosses reflecting type polarizing element 90c and light beam Lc is reflected back optical lens group 70c, and will be dissipated again by optical lens group 70c
Light beam Lc focus on polarization spectroscope 80c, and then light beam Lc is reflexed to by device for testing light 20c by polarization spectroscope 80c.By
This, can reduce the use of lens, and then reduce production cost；In addition, the part by optical circuit path overlaps, optics volume can be reduced
The overall volume of code device.
In the present embodiment, the first lens 71c and the second lens 73c of optical lens group 70c is respectively convex lens and recessed
Lens, but invention is not limited thereto.In other embodiments, the first lens and the second lens can distinctly be set according to actual demand
It is calculated as concavees lens or convex lens.
In addition, in the present embodiment, the feature that the quantity for the lens that optical lens group 70c includes is two is non-to limit this
Invention.In other embodiments, two optical lens groups of optical encoder can include one or three or more according to actual demand
Lens.
Light beam is focused on by the function of optical lens group converging beam according to the optical encoder of above-described embodiment
With by width only 6~10 microns of transparent area on coding disk, and the light focusing that will be dissipated by coding disk is to device for testing light,
By symmetrical optical projection principle, lens design, which is specifically imaged, receives optical position, and the light beam after enabling coding is with biggish
Width spacing is irradiated in device for testing light.In this way, the sensing element on device for testing light can have it is looser be arranged, make itself and coding
The aligning accuracy demand of disk reduces.The resolution obstacle that conventional codec encodes high precision position can be broken through as a result, while
Aligning accuracy can be reduced.In addition, focusing the light beam on coding disk by way of optically focused, make the light beam being irradiated on device for testing light
With biggish energy, thus the encoded signal for being irradiated in device for testing light can be made to be more clear, and then there is more preferably signal noise
Than.
In addition, the photomask of micro-led 2 microns of assortable line width or more used by light source module makes work
Skill production optical encoding disk, compared to laser diode and its high-precision photomask that need to be arranged in pairs or groups, it is micro-led and
To make the photomask lower production costs for the optical encoding disk arranged in pairs or groups with it.In addition, micro-led uses the longevity
It orders generally long compared with laser diode.Therefore, compared to laser diode, this case is used micro-led with high volume production
The characteristic of property and high durability.
Furthermore it is encoded by the thin partition type that coding pattern is parallelogram, difference is made with moving for coding disk
The sensing element of quantity senses light beam, and it is distinguishable go out different location, reach preferable resolving accuracy.In addition, thin partition type
Coding, which also can allow, differentiates the energy difference that adjacent sensing element senses light beam, can tell the position precision of multiple simultaneously,
The use number of sensing element can be reduced.
Claims (21)
1. a kind of optical encoder, characterized by comprising:
Light source module, to issue a light beam；
Device for testing light, to receive the light beam；
Coding disk, between the light source module and the device for testing light；
First optical lens group, between the light source module and the coding disk, first optical lens group and the light source module
A first distance is kept, first optical lens group and the coding disk keep a second distance；And
Second optical lens group, between the coding disk and the device for testing light, second optical lens group and the coding disk are kept
One third distance, second optical lens group and the device for testing light keep one the 4th distance；
Wherein, the first distance, the second distance, third distance and the 4th distance meet symmetrical optical projection principle
Definition, to enable first optical lens group that the light beam from the light source module is focused to the coding disk, and enable this second
The light beam for penetrating the coding disk is focused to the device for testing light by optical lens group.
2. optical encoder as described in claim 1, wherein the first distance is equal to the 4th distance, which is equal to
The third distance, and the first distance is different from the second distance.
3. optical encoder as described in claim 1, the wherein first distance, the second distance, third distance and should
4th distance is all equal.
4. optical encoder as described in claim 1, wherein the first distance is equal to the second distance, which is equal to
4th distance, and the first distance is different from the third distance.
5. the optical encoder as described in any in claim 2 to 4, wherein first optical lens group and second optics
Lens group respectively includes the first lens.
6. optical encoder as claimed in claim 5, wherein first optical lens group and second optical lens group are each
It also include the second lens, second lens of first optical lens group are close compared with first lens of first optical lens group
The coding disk, and second lens of second optical lens group compared with second optical lens group first lens close to the volume
Code-disc.
7. optical encoder as claimed in claim 6, wherein first optical lens group and second optical lens group are each
It also include the third lens, the third lens of first optical lens group are close compared with second lens of first optical lens group
The coding disk, and the third lens of second optical lens group compared with second optical lens group second lens close to the volume
Code-disc.
8. optical encoder as described in claim 1, wherein the coding disk includes multiple transparent areas and multiple opaque areas,
Those transparent areas and those opaque area's shapes are all essentially a quadrangle.
9. optical encoder as claimed in claim 8, wherein the quadrangle is a rectangle.
10. optical encoder as claimed in claim 8, wherein those transparent areas and those opaque area's arrangements interlaced with each other,
And the quadrangle is a parallelogram.
11. optical encoder as claimed in claim 8, wherein the width of those transparent areas is 6~10 microns.
12. optical encoder as described in claim 1, wherein the light source module is light emitting diode (LED) or miniature luminous
Diode array (Micro LED array).
13. optical encoder as described in claim 1, wherein the device for testing light is by least one sensing array module or multiple sensings
Element is formed.
14. optical encoder as claimed in claim 13, wherein at least one sensing array module and those sensing elements are
Light sensitive diode (Photodiode, PD) or avalanche-type light sensitive diode (Avalanche Photodiode, APD).
15. optical encoder as described in claim 1, also includes sensing circuit, which connects the device for testing light to divide
Distinguish the signal of device for testing light outflow.
16. a kind of optical encoder, characterized by comprising:
Light source module, to issue a light beam；
Coding disk is located on the beam path；
Device for testing light, to receive the light beam by the coding disk；
Optical lens group, between the light source module and the coding disk, the optical lens group and the light source module keep one the
One distance, the optical lens group and the coding disk keep a second distance；
Reflecting type polarizing element, the side positioned at the coding disk far from the optical lens group, to reflect by the coding disk
The light beam；And
Polarization spectroscope, between the light source module and the optical lens group, the polarization spectroscope and the optical lens group are protected
One the 5th distance is held, the polarization spectroscope and the device for testing light keep one the 6th distance；
Wherein, the sum total of the 5th distance and the 6th distance length is equal to the first distance, and the first distance, this second away from
From, meet the definition of symmetrical optical projection principle with a distance from the 5th with the 6th distance, to enable the optical lens group that will come from
The light source module simultaneously penetrates the light beam after the polarization spectroscope and focuses to the coding disk, and will be anti-by the reflecting type polarizing element
The light beam being emitted back towards focuses to the polarization spectroscope, then the light beam is reflexed to the device for testing light by the polarization spectroscope.
17. optical encoder as claimed in claim 16, wherein the first distance is different from the second distance.
18. optical encoder as claimed in claim 16, wherein the first distance is equal to the second distance.
19. the optical encoder as described in claim 17 or 18, wherein the optical lens group includes the first lens and second
Lens, and second lens compared with first lens close to the coding disk.
20. optical encoder as claimed in claim 16, wherein the coding disk includes multiple transparent areas and multiple opaque
Area, those transparent areas and those opaque areas arrangement interlaced with each other and shape is all essentially a parallelogram.
21. optical encoder as claimed in claim 16, wherein the reflecting type polarizing element is reflective silicon single liquid crystal cell
Part.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| TW106144566A TWI675187B (en) | 2017-12-19 | 2017-12-19 | Optical encoder |
| TW106144566 | 2017-12-19 |
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| CN109931965A true CN109931965A (en) | 2019-06-25 |
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| CN201711430809.8A Pending CN109931965A (en) | 2017-12-19 | 2017-12-26 | Optical encoder |
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| TW (1) | TWI675187B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113124911A (en) * | 2019-12-31 | 2021-07-16 | 财团法人工业技术研究院 | Optical encoder |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI710795B (en) * | 2019-12-04 | 2020-11-21 | 國立中興大學 | Optical rotary encoder |
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| TW201928303A (en) | 2019-07-16 |
| TWI675187B (en) | 2019-10-21 |
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