CN85105900A - Liquid crystal device for automatic exposition of camera - Google Patents
Liquid crystal device for automatic exposition of camera Download PDFInfo
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- CN85105900A CN85105900A CN85105900A CN85105900A CN85105900A CN 85105900 A CN85105900 A CN 85105900A CN 85105900 A CN85105900 A CN 85105900A CN 85105900 A CN85105900 A CN 85105900A CN 85105900 A CN85105900 A CN 85105900A
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- liquid crystal
- crystal cell
- cell
- control circuit
- camera
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- Diaphragms For Cameras (AREA)
Abstract
The invention discloses a kind of with liquid crystal device automatically control enter the luminous flux that for example resembles this class optical instrument of camera and don't influence its imaging and resemble the device of resolution.It is by the liquid crystal cell of particular design, the control circuit that the CMOS integrated circuit is formed and the photo-sensitive cell that has the adjustable damping plate: cadmium sulphide photoconductive cell three parts are formed.Transparency electrode is made a plurality of donuts by photoetching process on the substrate of liquid crystal cell, and going between respectively links to each other with control circuit.The resistance of photoresistance changes because of the strong and weak difference of illumination, thereby makes the control circuit action, and each donut appropriate section printing opacity or blocking on the control liquid crystal cell, finishes and does not have the auto iris effect that machinery moves.
Description
The present invention relates to a kind of non-mechanical with liquid crystal device automatically control for example enter as the luminous flux of this class optical instrument of camera and don't influence the device of its imaging performance.Existing automatic exposure of camera device kind is a lot, roughly can be divided into auto iris (speed is preferred) and automatic gate (aperture is preferred) two big classes.Automatically all be unable to do without the use mechanical movable part in the whole bag of tricks of control aperture in auto iris one class, structure is complicated, fragile and fragile, and cost is also higher.The present invention has replaced mechanical aperture with liquid crystal device, becomes the auto iris of not having the machinery action.Both improved reliability, the life-span of device, also reduced cost, and can link with shutter.Promptly adjust the size of aperture automatically according to time shutter length.The angle resolution of device can reach 10 at least, and " (second) has been five times of human eye.Photograph is enough.This device is not owing to have mechanical movable part thereby the life-span will be all longer than existing automatic exposure unit.Its unique shortcoming is that the luminous flux that enters camera will reduce about half, but the photoperceptivity of just present film, very big influence can not take place to imaging and record in it.Below the present invention is described in detail:
One, the structure of liquid crystal cell:
The structure of liquid crystal cell as shown in Figure 1.Its essential structure and general liquid crystal display device do not have any essential distinction, and just electrode need be made particular design according to camera.Polarizing coating and tackifier also have specific (special) requirements.(for example upper substrate) is inboard one of in the substrate slide of two liquid crystal cells (among Fig. 1 3.) carves as shown in Figure 2 shape with photoetching process.Electrode material can be tin oxide (SnO
2) also can be indium oxide (In
2O
3).Latter's transparency is better.Interelectrode interval is between 20 μ～100 μ, so Fig. 2 is the synoptic diagram that has amplified.Otherwise be beyond expression (during actual plate-making, is to draw earlier to amplify 10～20 times figure, final minification to 1 then: 1).Contact conductor also is this size.The diameter of the every circle of electrode can be the diaphragm diameter of the every frequency modulated light circle of used camera correspondence.Therefore every increase one circle, area that electrode encloses just increase and are twice.Electrode has several circles, and several extraction poles are just arranged.If being numbered of electrode from the inside to surface: 1., 2. ... 8., then just in time respectively with circuit in (shown in Figure 3) 1. → 8. electric extension line join.(F: 1.4) test, its diameter of lens is 3.6cm to Japanese Canon camera for we.Our electrode is made 8 circles, corresponding aperture.Corresponding aperture is 1.4; 2; 2.8; 4; 5.6; 8; 11; 16 o'clock diaphragm diameter, electrode diameter are: 3.6cm; 2.55cm; 1.8cm; 1.27cm; 0.90cm; 0.64cm; 0.45cm; 0.32cm.Certainly can be other size fully according to following principle electrode diameter, as long as match with circuit.Multiple transparency electrode is then all draped over one's shoulders in another substrate of liquid crystal cell (for example infrabasal plate) inboard.In extension line and the circuit (shown in Figure 3)
Number join.Be filled with the liquid crystal layer of 10 μ left and right thicknesses in the middle of the liquid crystal cell.Belong to distortion-nematic crystal.This with general display device in fill the same, 6 volts of peak-to-peak value square-wave voltages can be driven, and make the liquid crystal can be from 40 ℃ →-10 ℃ work.The both sides of liquid crystal cell use respectively neutral gum gluing polarizing coating (artificial polarizing coating).Polarizing coating is outer again with the neutral gum thick cover glass (the smooth glass of optics) of 0.1mm that bondd.The optical direction of polarizing coating can be vertical each other, makes liquid crystal cell often open (being the logical light of liquid crystal cell when comparative electrode does not add square-wave voltage between base plate for liquid crystal cell); Also can be parallel to each other, make liquid crystal cell become closed type when making alive (promptly not be obstructed light).Below we are described all for closed type.
It must be noted that requirement is higher to polarizing coating in the present invention.Its transmitance requires more than 40%, and degree of polarization can not be lower than 98%; And require smooth and refractive index even, otherwise all can influence the light transmission and the resolution of device.Reason is that natural light is divided into e light and O light after by polarizing coating, and O light is absorbed by polaroid sheet is most of, and only allows e light pass through.If the O light transmission is too many, can cause serious birefringence, image will blur, and detail section will be unclear, and resolution reduces greatly.Bonding also is relative with glue object matter.My experience is for well with center natural gum.
It is in order to protect polarizing coating, to make its not moisture-sensitive, be difficult for sanding, the more important thing is in order to make a smooth optical flat that polarizing coating is stained with the thick cover glass of 0.1mm one outward again.Because general artificial polarizing coating is also not really smooth, can not grind again, this also will influence and resemble matter.When gluing behind the cover glass, and the refractive index of neutral gum and slide and polarizing coating are all very approaching, and the flatness of device has just obtained improving greatly.
The thickness of base plate for liquid crystal cell look its size and different.To compact camera, the substrate of available 0.5mm then when the diameter of box is no more than 2cm.Camera (φ the surpasses 3cm) substrate that then 0.5mm is thick to macro lens just can not guarantee the strong and indeformable of liquid crystal cell, therefore just should use the above slide of 0.7mm.
The principle of work of liquid crystal cell can find here on general book and not lay down a definition.(as, " the LCD "-product description that can write with reference to Shanghai Hong Feng semiconductor element factory)
Two, control circuit
Control circuit all adopts the low voltage cmos integrated package, and it has operating voltage low (minimum 3 volts), the characteristics that power consumption is little.The power supply of this device is 3 volts a button cell.It just in time can drive liquid crystal cell work through oscillatory circuit and the exportable 6 volts peak-to-peak value work oscillating voltage of XOR gate.
Circuit as shown in Figure 3, the upper left side is an oscillator, its generating period is the square wave of 5ms.Receive infrabasal plate electrode and eight XOR gate input ends of liquid crystal cell.Light activated element is cadmium sulphide photoconductive cell (homemade), its characteristic curve such as Fig. 4, photoresistance R
PBelow the series connection eight resistance R
1→ R
3(its resistance is relevant with electrode design) is to ground.The upper end of every resistance is drawn a line and is inserted phase inverter, and the counter-rotating level of phase inverter almost is the same (having six phase inverters among the CC4069) in same integrated package, differs and is no more than 0.01 volt.8 reversers are served as by two CC4069, so these two circuit will select symmetrically, the level that promptly reverses almost equal (error must not above 0.01 volt).Work as us in this circuit and select V
DDIn the time of=3 volts, the counter-rotating level of phase inverter is 1.6 ± 0.01 volts.As cadmium sulphide photoconductive cell R
PResistance decreasing when being subjected to illumination strong, terminal potential will rise on its each resistance that connects down, along with the upset successively from top to bottom of each phase inverter in the illumination stiffening ring 3 (by the output high level to low level), XOR gate output terminal thereafter and
8. → 1. oscillating voltage between number line will be by successively disappearing, and the liquid crystal cell that connects with it shows is then closed to interior ring successively by outer shroud.So illumination is strong more, the liquid crystal cell clear aperature is littler, has just in time played the auto iris effect.R in the circuit
PWith R
1→ R
8Played voltage generator, eight phase inverters have played voltage comparator, and eight XOR gate have played control and transformed oscillating voltage.Resistance value in the circuit is to calculate like this:
The light of cadmium sulfide-resistance characteristic curve (has added attenuating plate) as shown in Figure 4 before cadmium sulfide, corresponding each exposure value EV, and cadmium sulfide all has a corresponding resistance R
P, when the EV value hour (EV=10) aperture is all opened.Work as EV=11, R
P=4K then should make liquid crystal aperture outmost turns close, and promptly h point current potential should be just for 1.6V(makes the phase inverter output low level among Fig. 3, make 8. with
Between do not have potential difference (PD)).At this moment a, b ... g each point current potential all is lower than 1.6V, then corresponding phase inverter output high level, and therefore 1. → 7. enclosing aperture is to lead to light, can list following equation according to this point:
(R
1+R
2+…+R3)/(R1+…+R3+R
P) ×3=1.6
That is: (R
1+ R
2+ ... + R
3)/(R
1+ R
2+ ... + R
3+ 4) * 3=1.6 (1)
In like manner, R when EV=12
P=2.4K, should make g point current potential is 1.6 volts, make the liquid crystal aperture 7. 8. two the circle apertures close, this can list:
(R
1+…+R
7)/(R
1+…+R
8+2.4) ×3=1.6（2）
Work as EV=13,14 ... can list equation equally: (R
PValue is seen Fig. 4)
(R
1+…+R
6)/(R
1+…+R
8+1.4) ×3=1.6（3）
(R
1+…+R
5)/(R
1+…+R
8+0.9) ×3=1.6（4）
(R
1+…+R
4)/(R
1+…+R
8+0.5) ×3=1.6（5）
(R
1+…+R
3)/(R
1+…+R
8+0.33) ×3=1.6（6）
(R
1+R
2)/((R
1+…+R
8+0.2)) ×3=1.6（7）
〔R
1/（R
1+…+R
8+0.13）〕×3＝1.6（8）
Can solve R by equation (1) → (8)
1, R
2... R
8Value, they are respectively:
R
1＝2.51K;R
2＝0.03K;R
3＝0.07K;R
4＝0.09K;
R
5＝0.22K;R
6＝0.26K;R
7＝0.54K;R
8＝0.85K.
R
1With 3.3K potentiometer generation.
Three, the photo-sensitive cell (see figure 5) that adds the adjustable damping plate
When the time shutter shortened one times, requirement aperture under same EV value was opened a circle more.We realize this point by the attenuating plate that can change of equipment before photoresistance in order to realize this point.We change synchronously the replacing of this attenuating plate and time shutter.Shutter speed adds and is twice, and decay adds and is twice, at this moment R
P～EV family curve the unit that will move to right.It is the corresponding resistance R of present EV value
PValue will be (EV-1) pairing resistance before attenuating plate is changed.They for example no longer be 2.4K now when EV=12, but 4K, thereby aperture is just automatically opens a circle more, makes 1. → 7. open, rather than just now 1. → 6. open.Exposure is just just in time suitable like this.When extraneous EV=13 aperture open automatically 1. → 6., and the like.
Attenuating plate can be made of three rotating relatively polarizing coatings simply.If two polarizing coating angular separations are θ, then by light intensity I and incident intensity I
0Between relation be:
I＝〔I
0cos
2θ〕· 1/2
The angle θ that rotates should be corresponding with the time shutter, and promptly the time shutter shortens half, and by the luminous flux of attenuating plate, thereby light intensity also must reduce half.When the light sensitivity of the film that uses changes, can convert variation equally into exposure value, therefore also can lean on the rotational delay plate 2. to proofread and correct, no longer repeat.(following formula is approximate to be because in fact polarizing coating also has attenuation by absorption, and must suppose that the polarizing coating degree of polarization is 100%).
After finishing, element manufacturing before using for the first time, also must do once debugging.Polaroid 1., 3. between angle theta
1Before the long span T(B door of=0 o'clock corresponding time shutter).At this moment adjust polaroid 2. 3. between angle theta
2, make it suitable to used egative film exposure, later on as long as the egative film light sensitivity is constant, θ
2Just no longer change, debug the automatic exposure unit of the camera that finishes like this and just can use.
As time shutter t → 1/2 T; 1/2 T; Corresponding θ
1Should be:
θ when changing the egative film light sensitivity of being tried out
2Need readjust, this can survey θ to various light sensitivity in advance
2, on index dial, perform indication, stir θ then
2Get final product.
Four, guide into by the B point in when liquid crystal cell is made open type, only needing Fig. 3
Line make into to draw and get final product from the A point, other connection is all constant.
Five, when the compound lens of camera lens has planar interface, liquid crystal cell can directly be made in (solid-liquid crystal layer thickness is 10 μ only) in this planar interface gap.When technology is permitted in addition liquid crystal cell can be made in the layer of sphere crack.
Six, when liquid crystal cell is made open type, can dispose a manual aperture again, like this, when dump, just can use manual iris at once, become automatically and dual-use manual.
Description of drawings:
Fig. 1 is the liquid crystal cell sectional view.
1. cover glass (0.1mm is thick).
2. polarization film (0.1mm is thick).
3. liquid crystal cell slide (0.5～0.7mm is thick).
4. liquid crystal layer (10 μ are thick).
5. liquid crystal cell packing ring (10 μ are thick).
Beating the oblique line place is neutral tree glue-line (thick about 10 μ).
Fig. 2 is the transparent electrode structure synoptic diagram on the liquid crystal cell slide, 1. 2. ... 8. the expression electrode numbering of drawing.
Fig. 3 is control circuit figure.
Fig. 4 is the light-resistance characteristic curve map of photoresistance (cadmium sulfide).
Fig. 5 is the photo-sensitive cell structural drawing of band adjustable damping plate.
1., 2. represent the movable polarizing sheet.
3. represent fixedly polaroid.
4. be cadmium sulphide photoconductive cell.
Polaroid rotation and the interlock of time shutter gear shift knob 2..
Claims (4)
1, reaches the automatic diaphragm setting device of the nothing machinery action of forming by photo-sensitive cell three parts of adjustable damping plate that can be used for camera by liquid crystal cell, control circuit.It is characterized in that
A, the liquid crystal cell of a particular design and processing is arranged, thereby make it play the auto iris effect, and reach the angle resolution and be not more than 9.98 " (second).
B, by a low power consumpting controling circuit of all forming with the low voltage CMOS integrated circuit.
C, light activated element use cds (cadmium sulfide), and have and can change synchronous adjustable damping plate with the time shutter.
2, device according to claim 1, wherein the feature of liquid crystal cell is: transparency electrode is designed to concentric ring, and employing goes between as Fig. 2 mode.The size of garden ring equates with each frequency modulated light loop diameter of general camera respectively.The thickness of lead-in wire and interval are all between 20 μ～100 μ.The liquid crystal cell both sides are pasted with artificial polarizing coating, require its transmitance greater than 40%, and degree of polarization is greater than 98%.The polarizing coating both sides are pasted with the flat slide of optics of 0.1mm again.Paste and all adopt neutral gum.When in the compound lens of camera lens planar interface being arranged, dense brilliant box can be made in this interplanar every in.When allowing, technology also can be made in the sphere interval of lens.
3, according to the described device of claim 1, control circuit utilizes CMOS integrated circuit: CC4069(six side phase devices) with CC4030(four XOR gate) wherein three phase inverters are connected into square-wave generator among the CC4069, and eight phase inverters utilize its on-level to have only 0.01 volt difference as level comparator, and utilize cadmium sulphide photoconductive cell directly to connect as voltage generator, and utilize the CC4030 XOR gate to make the output waveform controller with eight resistance.A point in oscillator or B point (see figure 3) and liquid crystal cell public electrode
When joining, can make liquid crystal cell work in open type or closed type.
4,, add the variable attenuation plate before the photo-sensitive cell cds photoresistance, thereby make control circuit and time shutter interlock, and adapt with used egative film light sensitivity according to the described device of claim 1.It is characterized in that nothing electrically contacts, and makes device reliably reasonable.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN85105900A CN85105900A (en) | 1985-07-26 | 1985-07-26 | Liquid crystal device for automatic exposition of camera |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN85105900A CN85105900A (en) | 1985-07-26 | 1985-07-26 | Liquid crystal device for automatic exposition of camera |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN85105900A true CN85105900A (en) | 1986-02-10 |
Family
ID=4794763
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN85105900A Pending CN85105900A (en) | 1985-07-26 | 1985-07-26 | Liquid crystal device for automatic exposition of camera |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN85105900A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104345508A (en) * | 2014-11-05 | 2015-02-11 | 华中科技大学 | Electric control liquid crystal laser shaping chip based on wave front adjustment |
| CN105866998A (en) * | 2016-06-02 | 2016-08-17 | 京东方科技集团股份有限公司 | Display device |
| CN111432103A (en) * | 2020-04-03 | 2020-07-17 | 深圳传音控股股份有限公司 | Mobile terminal, control method of mobile terminal, and computer storage medium |
-
1985
- 1985-07-26 CN CN85105900A patent/CN85105900A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104345508A (en) * | 2014-11-05 | 2015-02-11 | 华中科技大学 | Electric control liquid crystal laser shaping chip based on wave front adjustment |
| CN104345508B (en) * | 2014-11-05 | 2017-01-18 | 华中科技大学 | Electric control liquid crystal laser shaping chip based on wave front adjustment |
| CN105866998A (en) * | 2016-06-02 | 2016-08-17 | 京东方科技集团股份有限公司 | Display device |
| CN111432103A (en) * | 2020-04-03 | 2020-07-17 | 深圳传音控股股份有限公司 | Mobile terminal, control method of mobile terminal, and computer storage medium |
| CN111432103B (en) * | 2020-04-03 | 2021-12-14 | 深圳传音控股股份有限公司 | Mobile terminal, control method of mobile terminal, and computer storage medium |
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