CN102394206B - System and method for aligning shadow mask motherboard precisely and automatically - Google Patents

Abstract

The invention relates to the technical field of manufacturing of display devices and provides a system and a method for realizing precise and automatic alignment of a shadow mask motherboard by a diffraction stacked gate signal technology. By detecting the positional deviation by a differential stacked gate signal technology, the relative position deviation between two glass motherboards can be detected effectively, and higher detection precision can be guaranteed. The method comprises the following steps of: taking a zero-time stacked gate signal as a control signal by an alignment system; converting the control signal into an electrical signal by a photodiode; amplifying and filtering, and converting the electrical signal into a digital signal by an analog to digital converter (A/D converter); inputting the digital signal into an industrial control computer; and determining the size and direction of the positional deviation according to the input signal and then sending a corresponding driving pulse signal by a microcomputer to ensure a stepping motor drives a mobile motherboard by different steps so as to reach the required positional precision range, and finally aligning the mobile motherboard with a fixed motherboard completely. By adopting a series of anti-jamming measures in the aspects of software and hardware, the system guarantees higher alignment precision and work reliability, wherein the alignment precision is +/-0.5mu m.

Description

The accurate Automatic Alignment System of shadow mask motherboard and method thereof

Technical field

The present invention relates to the folded gate signal technology of a kind of employing diffraction and realize the accurate Automatic Alignment System of shadow mask motherboard and method, belong to display devices and manufacture field.

Background technology

Shadow mask is the critical elements of color monitor, is placed in the display screen back, is used for controlling the fluoroscopic scanning pattern of beam bombardment and Pixel Dimensions.Planar mask is the sheet metal that a kind of thickness is less than 1mm, is furnished with the pore of a hundreds of thousands rule on it, the long 0.6mm in hole, and the wide 0.2mm in hole, requiring error is several microns.

The aligning of shadow mask motherboard is most important manufacturing procedure in shadow mask processing.In process of production, scribble the steel band of photosensitive material between two glass mother boards, wherein, a glass mother board is arranged on to be determined to maintain static on framework, another piece glass mother board is arranged on moving framework, as shown in Figure 1, and by adjustment cam mechanism, can make the glass mother board on framework move with respect to the glass mother board of determining on framework, thereby two glass mother boards are aimed at fully.Owing to being painted with symmetrical pore pattern on two glass mother boards, after the exposure of certain hour, form respectively the symmetrical projection pattern of pore in the steel plate both sides like this, just form the pore identical with the motherboard pattern on steel plate after corrosion treatment, form planar mask.

At present, the aligning of two glass mother boards is the alignment marks that adopt on the microscopic examination glass plate, or else the work of cutting off the hands regulation moving frame position, progressively make two motherboards aim at, this method is inefficiency not only, and machining accuracy is difficult to guarantee, seriously restricting the raising of production efficiency and conforming product rate.

Summary of the invention

The object of the present invention is to provide a kind of can be fast, reliable, the self-aligning system and method for done with high accuracy shadow mask motherboard.

For achieving the above object, the technical scheme that alignment system of the present invention is taked is:

The accurate Automatic Alignment System of shadow mask motherboard, comprise semiconductor laser, spectroscope, moving framework, determine framework, differential grating, photodiode, signal processing circuit, A/D converter, industrial control computer, stepping motor and driver, the precision cam driving mechanism, wherein, semiconductor laser and spectroscope are in moving framework and a side of determining framework, and photodiode, signal processing circuit, A/D converter, industrial control computer is in moving framework and the opposite side of determining framework, for receiving 0 folded grid light signal after optical grating diffraction, two glass mother boards that are carved with grating are arranged on respectively moving framework and determine on framework, stepping motor and driver and precision cam driving mechanism are arranged on moving framework, for driving the glass mother board on moving framework, differential grating is by each four groups of optical grating constitutions that arrange on two glass mother boards, the precision cam driving mechanism comprises four springs and four cams, and described spring is divided into one group in twos, is separately positioned on the place, diagonal angle of moving framework, and four springs are connected on the four edges of moving framework, described cam is divided into one group in twos, is separately positioned on the place, other a pair of diagonal angle of moving framework, and four cams also contact with the four edges of moving framework respectively, and four cams are rotated by four driven by servomotor, described signal processing circuit is comprised of current/voltage-converted circuit, amplifying circuit, filter circuit and zeroing circuit level Four.

The technical scheme that alignment methods of the present invention is taked is:

The accurate automatic aligning method of shadow mask motherboard comprises the following steps:

(1) carry out slightly to plate: at the symmetrical place up and down of two glass mother boards, be provided with two "+" fonts to the plate mark; By magnifying glass, manually will move the framework glass mother board and determine the framework glass mother board and carry out coarse alignment, its alignment precision is ± 50 μm;

After (2) two glass mother board coarse alignments, then carry out precision automatically to plate: four springs of precision cam driving mechanism and the relative clamping in twos of four cams, steady with the motion that guarantees moving framework; The minute angle displacement that cam mechanism will segment rear motor is converted into micron-sized linear displacement, it is control signal that industrial control computer is got the differential folded gate signal of transmission zero degree, and send corresponding drive pulse signal according to size and the polarity of differential folded gate signal, make motor drive moving framework to reach desired positional precision scope; When alignment system is disturbed, the differential folded gate signal curve biased error band of reflection change in location, industrial control computer just can send corresponding control impuls, automatically reset, the relative position deviation of two glass mother boards is controlled in desired accuracy rating all the time, realizes fine registration.

Alignment system of the present invention be take industrial control computer as core, control and realize that high precision position detects and accurate auto-alignment by microcomputer, to take a series of interference protection measures aspect soft and hardware, guaranteed higher alignment precision and functional reliability, alignment precision can reach ± and 0.5 μm.The compound aligning of two-part that alignment methods of the present invention adopts coarse alignment to combine with fine alignment, can make the fine registration workbench reach the high-precision while, can greatly shorten the aligning time again, realizes high speed, high precision alignment control.

The accompanying drawing explanation

Fig. 1 is the shadow mask motherboard frame structure schematic diagram of prior art.

Fig. 2 (a) is the structured flowchart of shadow mask motherboard fine registration platform of the present invention; (b) be the differential grating structure chart.

Fig. 3 is the structure chart of precision cam driving mechanism in alignment system of the present invention.

Fig. 4 is photosignal testing circuit figure in alignment system of the present invention.

Fig. 5 (a) is the differential stacked gate structure figure adopted in the embodiment of the present invention, is (b) differential folded gate signal curve chart.

Fig. 6 is the experimental result that adopts the fine registration method to obtain in the embodiment of the present invention: (a) primitive curve, (b) non-cumulative curve.

Embodiment

The accurate Automatic Alignment System of shadow mask motherboard of the present invention as shown in Figure 2.In order effectively to detect the relative position deviation of two glass mother boards, four groups of gratings respectively are set on two glass mother boards, grating group 1-2,3-4,5-6 are relative in twos, form the differential grating structure, to improve the sensitivity of position detection signal, wherein grating group 1-2,5-6 detection level position deviation, grating group 3-4 detection of vertical position deviation, because the distance of upper and lower 2 is fixing, so Y-direction only need arrange one group of grating.Grating 8 is one group of round grating, when moving plate with determine plate fully on time, the light intensity of passing through is 0.7 tunnels are the primary light without optical grating diffraction, by detecting the light intensity of this Shu Guang, can reflect in real time the variation of lasing light emitter light intensity, for the luminosity compensation to punctual.

Be provided with the precision cam driving mechanism on the moving framework of system, as shown in Figure 3, four springs and the relative clamping in twos of four cams, to guarantee its motion steadily.Cam turns clockwise and forms the micrometric displacement linear advancement, be rotated counterclockwise formation micrometric displacement straight line and retreat, any one direction motion of micropositioner, form by 4 cam linkages, produce vertical, horizontal and rotate three kinds of motions, four cams are rotated by four driven by servomotor.The driving of micropositioner adopts pulse segmentation formula stepping motor, and by high accuracy Archimedes spiral cam mechanism, the minute angle displacement of stepping motor after segmentation is converted into to micron-sized linear displacement, aim to meet the needs of controlling, final alignment error will mainly rely on computer closed loop control to be used for eliminating, and reduce the dependence to the machining accuracy of mechanical driving part own as far as possible.Industrial computer often sends a pulse, corresponding stepping motor driving cam rotation 0.03o, and micropositioner moves 0.2 μm.

Photoelectric signal processing circuit is comprised of current/voltage-converted circuit, amplifying circuit, filter circuit, zeroing circuit level Four.Photodiode is accepted 0 folded grid light signal after optical grating diffraction, and light intensity signal is converted to the signal of telecommunication, by the current/voltage-converted circuit, the current signal of microampere order is converted to the microvolt magnitude voltage signals, then is amplified by amplifying circuit.Filter adopts the divalence low pass filter, can effectively eliminate the impact of high-frequency interferencing signal, and adds therein the low-pass filtering T network so that the noise of further filtering 50Hz.In addition, Circnit Layout zeroing circuit, can effectively eliminate the null offset of photodiode dark current and operational amplifier, improve position detection accuracy.

Computer control device adopts industrial control computer that antijamming capability the is strong core as system, industrial computer adopts high performance PCL-818L data collecting plate card, 16 passage relay output end daughter board PCLD-785,16 road light isolation D/I terminal board PCLD-782 and PCA-6167 series mainboard, the built-in technical grade CPU of mainboard card.

Three-phase hybrid stepping motor and driver that drive unit adopts German hundred Ge La companies to produce.The 6020 serial isa bus three-axis stepping motor control cards that stepping motor drives control card to adopt four-way motor company to produce, this control card can accurately be controlled sent pulse frequency (motor speed), pulse number (motor corner) and frequency change rate (motor acceleration), and it can meet the various complex control requirements of stepping motor.

Utilize the accurate auto-alignment platform of above-mentioned shadow mask motherboard, alignment methods of the present invention is:

(1) carry out slightly plate, at the symmetrical place up and down of two glass mother boards, be provided with two "+" fonts to the plate mark.By magnifying glass, manually will move the framework glass mother board and determine the framework glass mother board and carry out coarse alignment, its alignment precision is ± 50 μm, during work, two motherboards are in clamped condition, and centre has been pumped into vacuum, and suitably adjusts two sheet separations.

(2) adopt differential folded gate signal technology for detection position deviation.When two gratings relatively move, the relative displacement of folded gate signal intensity two gratings is cyclic variation, by photodiode, the folded grid light of the zero degree of transmission is converted to the signal of telecommunication, and, by the folded grid light signal strength of COMPUTER DETECTION zero degree, can determines the relative shift between two sheet grations.For effectively improving the sensitivity of position detection signal, arrange two groups of stagger respectively+d/4 and-grating of d/4, when this two groups of gratings of laser process, can obtain two anti-phase folded gate signals, the difference (being differential folded gate signal) of getting two folded gate signals is the position deviation detection signal.Differential folded gate signal will reflect that the light intensity value of change in displacement has amplified one times effectively, particularly near alignment point, the rate of change of differential folded gate signal is very steep, micro-displacement just can cause large light intensity to change, and has greatly improved sensitivity and the positioning precision of position detection signal.

(3) after two glass mother board coarse alignments, enter the scope that grating detects, then carry out precision automatically to plate.To on time, 0 differential folded gate signal of transmission, by photodiode converts, it is the signal of telecommunication, after amplification, filtering etc. are processed, be converted to digital signal by A/D converter, the input industrial control computer, industrial computer sends corresponding drive pulse signal according to size and the polarity of differential folded gate signal, makes the Design of Stepper Motor Subdivision step drive micropositioner to reach desired positional precision scope.When system is disturbed, the differential folded gate signal curve biased error band of reflection change in location, industrial computer just can send corresponding control impuls, automatically reset, position deviation is controlled in desired accuracy rating all the time, realizes fine registration, its alignment precision is ± 0.5 μm.

Claims (4)

1. the accurate Automatic Alignment System of shadow mask motherboard, comprise semiconductor laser, spectroscope, moving framework, determine framework, differential grating, photodiode, signal processing circuit, A/D converter, industrial control computer, stepping motor and driver, the precision cam driving mechanism, wherein semiconductor laser and spectroscope are in moving framework and a side of determining framework, and photodiode, signal processing circuit, A/D converter, industrial control computer is in moving framework and the opposite side of determining framework, for receiving 0 folded grid light signal after optical grating diffraction, two glass mother boards that are carved with grating are arranged on respectively moving framework and determine on framework, stepping motor and driver and precision cam driving mechanism are arranged on moving framework, for driving the glass mother board on moving framework, it is characterized in that: differential grating is by each four groups of optical grating constitutions that arrange on two glass mother boards, the precision cam driving mechanism comprises four springs and four cams, and described spring is divided into one group in twos, is separately positioned on the place, diagonal angle of moving framework, and four springs are connected on the four edges of moving framework, described cam is divided into one group in twos, is separately positioned on the place, other a pair of diagonal angle of moving framework, and four cams also contact with the four edges of moving framework respectively, and four cams are rotated by four driven by servomotor, described signal processing circuit is comprised of current/voltage-converted circuit, amplifying circuit, filter circuit and zeroing circuit level Four.

2. the accurate Automatic Alignment System of shadow mask motherboard according to claim 1, it is characterized in that: form in four groups of gratings of described differential grating, two groups of gratings are used for detecting the relative level position deviation of two glass mother boards, one group of grating is used for detecting the relative vertical position deviation of two glass mother boards, and other one group of grating is the circle grating.

3. the accurate Automatic Alignment System of shadow mask motherboard according to claim 1 and 2, is characterized in that: described cam employing Archimedes spiral cam mechanism, its driving employing pulse segmentation formula stepping motor.

4. utilize the alignment methods of the accurate Automatic Alignment System of shadow mask motherboard as claimed in claim 1, it is characterized in that:

(1) carry out slightly to plate: at the symmetrical place up and down of two glass mother boards, be provided with two "+" fonts to the plate mark; By magnifying glass, manually will move the framework glass mother board and determine the framework glass mother board and carry out coarse alignment;

After (2) two glass mother board coarse alignments, then carry out precision automatically to plate: four springs of precision cam driving mechanism and the relative clamping in twos of four cams, steady with the motion that guarantees moving framework; The minute angle displacement that cam mechanism will segment rear motor is converted into micron-sized linear displacement, it is control signal that industrial control computer is got the differential folded gate signal of transmission zero degree, and send corresponding drive pulse signal according to size and the polarity of differential folded gate signal, make motor drive moving framework to reach desired positional precision scope; When alignment system is disturbed, the differential folded gate signal curve biased error band of reflection change in location, industrial control computer just can send corresponding control impuls, automatically reset, the relative position deviation of two glass mother boards is controlled in desired accuracy rating all the time, realizes fine registration.

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