GB2215477A - Apparatus for use in producing a multiple image mask to be employed in photolithographic processing - Google Patents
Apparatus for use in producing a multiple image mask to be employed in photolithographic processing Download PDFInfo
- Publication number
- GB2215477A GB2215477A GB8804793A GB8804793A GB2215477A GB 2215477 A GB2215477 A GB 2215477A GB 8804793 A GB8804793 A GB 8804793A GB 8804793 A GB8804793 A GB 8804793A GB 2215477 A GB2215477 A GB 2215477A
- Authority
- GB
- United Kingdom
- Prior art keywords
- film
- platen
- producing
- image
- developed
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/20—Exposure; Apparatus therefor
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
Abstract
Apparatus for use in producing a multiple image mask, to be employed in processing, for example, printed circuit boards, includes a machine having a horizontal platen 11 to support an initially unexposed film, a light spot projector (not shown), and means to displace the projector relative to the platen. In a first stage of the operation of the apparatus, the plotting machine is employed in a conventional manner, in producing a first film 30 with a single, desired image provided with thereon. Then the first film is developed and is relocated on the platen in precisely the same registration as before. A contact printer 40 is mounted in the place of the projector, and means is provided whereby the first film is moved vertically to be mounted on the printer. The apparatus is now employed in producing a second film 70 with an array of a plurality of identical, desired, images. The second film is mounted on the platen 11 in precisely the same registration as the first film. The contact printer is displaced, as by a step-and-repeat mechanism, and at each of the constituent image locations of the array is employed to expose selectively regions of the second film through the developed first film. <IMAGE>
Description
APPARATUS FOR USE IN PRODUCING A MULTIPLE IMAGE
MASK TO BE EMPLOYED IN PHOTOLITHOGRAPHIC PROCESSING
THIS INVENTION relates to apparatus for use in producing a multiple image mask to be employed in photolithographic processing.
It is known in producing a single image mask for use in photolithographic processing in, say, the manufacture of a single printed circuit board at a time, to employ a plotting machine in producing a film with a developed single image thereon. The film with the developed image either comprises, or is employed in producing, the desired mask. In any event, the image developed on the film, at least, corresponds to the image required to be reproduced by the mask in the photolithographic processing.
The plotting machine includes a horizontal platen to support an initially unexposed, photographic film, a light spot projector, and means to displace the projector relative to the platen in two horizontal orthogonal directions. Selected regions of the film are exposed selectively, by the light spot from the projector traversing the selected regions of the film, the displacing means being controlled, and the projector being switched on and off, in the appropriate way. Subsequently, the exposed film is removed from the plotting machine, and the required single image on the film is developed, this developed image being provided by the film regions selectively exposed in the plotting machine.
For convenience, in this specification, and the accompanying claims, reference will be made to the plotting machine, and/or to a film selectively exposed in the plotting machine, as being employed in producing the film with the required developed image, and/or as being employed in producing a desired mask for reproducing the required image in photolithographic processing.
It is known in producing a multiple image mask, having an array of a plurality of identical, desired, images for use in photolithographic processing in, say, the manufacture of said plurality of printed circuit boards in a batch, to provide an array of images on a developed film, the array, at least, corresponding to the array of multiple images required to be reproduced by the mask in the photolithographic processing.
In a known way in producing such a multiple image film, a developed, single image, film, produced partially by a plotting machine as referred to above, is employed. The first, developed, single image film is transferred to apparatus separate from the plotting machine. In the apparatus the first film is moved, in the required manner, relative to a second, initially unexposed, film to be provided with the array of images. The first film is moved, to be in registration sequentially with each constituent image location of the array to be provided on the second film, by a step-and-repeat mechanism included in the apparatus. When the first film is in registration with each such constituent image location, the selected regions of the second film are exposed selectively by radiation passing through the developed first film in the appropriate manner.Subsequently, the exposed second film is removed from the apparatus, and developed, to provide the required array of multiple images thereon. Desirably, the first, single image film, and the second, multiple image film, are precisely in the required registration in relation to each other at each constituent image location of the array.
Inherently, such precise registration cannot be obtained, because the first film has been transfered from the plotting machine to the separate apparatus including the step-and-repeat mechanism, and inaccuracies are introduced into the multiple image film.
Alternatively, it is known, in producing the required multiple image film, to mount an initially unexposed film on the platen of a plotting machine, and to expose selectively regions of the film sequentially at the location of each constituent image of the desired array, in the manner referred to above. At each such image location the selected regions of the film, corresponding to a single constituent image, are exposed. Such a procedure in producing a film with the required array of multiple images, although substantially accurate, is time consuming.
It is an object of the present invention to provide apparatus for use in producing a multiple image mask, the mask to be employed in photolithographic processing, and the apparatus including a known form of plotting machine, in a first stage of the operation of the apparatus the plotting machine being employed in a conventional manner, in producing a developed first film with a single, desired, image thereon, and in a second stage the displacing means of the plotting machine being employed as a step-and-repeat mechanism, displacing the developed first film, sequentially, to the location of each constituent image of an array of images required on an initially unexposed, second film, when the second film is mounted in the plotting machine, at each constituent image location, selected regions of the second film being exposed by employing the developed first film.
According to the present invention apparatus for use in producing a multiple image mask, the mask to be employed in photolithographic processing, includes a known form of plotting machine, the plotting machine having a platen to support an initially unexposed photographic film, a light spot projector, and means to displace the projector relative to the platen in two orthogonal directions, in a first stage of the operation of the apparatus, with the plotting machine to be employed in a conventional manner, and in producing a single, desired, image on a first film, when developed, the displacing means is to be controlled in the appropriate way, so that selected regions of the first film are to be exposed selectively, by the light spot from the projector traversing the selected regions, and the apparatus also includes a contact printer, possibly the contact printer being provided only temporarily during a second stage of the operation of the apparatus, and possibly replacing the light spot projector, with any such arrangement, the displacing means of the plotting machine to displace the contact printer relative to the platen in the two orthogonal directions, in the same manner as with the projector in the first stage, in the second stage of the operation of the apparatus, initially, the developed first film provided with the single image is to be located on the platen in precisely the same registration as in the first stage, and transfer means is provided in the apparatus whereby, subsequently, the first film is to be transferred to be mounted on the contact printer, and thereby is to be moved, initially, precisely along the third orthogonal direction, an initially unexposed, second film to be provided with an array of a plurality of identical, desired images, is to replace on the platen, and is to be precisely in the same registration as, the first film, in the second stage the displacing means is to be controlled in the appropriate way, as if comprising a step-and-repeat mechanism, so that the first film is to be moved relative to the second film, sequentially, to be in precise registration with each constituent image location of the array to be provided on the second film, with the first film in precise registration with each such location, selected regions of the second film are to be exposed selectively by employing the contact printer with the first film mounted thereon, in producing the second film with the required array of desired images provided thereon.
Hence, a desired film, provided with the array of required images, can be produced more conveniently, and/or in a more accurate manner, than by employing known apparatus. In particular, apparatus in accordance with the present invention employs the plotting machine for less time than when plotting each constituent image of the array consecutively; and because the developed first film is transferred precisely in the third orthogonal direction within the sole apparatus, and is not moved to separate apparatus, in producing the second film, and because the second film is mounted on the platen of the plotting machine in exactly the same registration as the previous mounting of the first film on the platen, registration between the first and second films at each constituent image location of the required array is greater than otherwise would be the case.
The present invention will now be described by way of example with reference to the accompanying drawings, in which
Figure 1 is a plan view of a known form of plotting machine, when employed in producing a film with a single, desired, image provided thereon, a platen, and a light spot projector, of the plotting machine being shown hatched for the sake of clarity,
Figure 2 corresponds to Figure 1, and shows the known plotting machine when employed in producing a film with an array of a plurality of identical, desired, images provided thereon, each constituent image of the array being plotted consecutively by the plotting machine,
Figures 3 to 9 show a plotting machine, capable of being modified from the form shown in Figures 1 and 2, the plotting machine being included in apparatus in accordance with the present invention, to be employed in producing a film with an array of a plurality of identical, desired, images provided thereon, in a manner differing from that illustrated in Figure 2,
Figure 3, corresponds to Figure 1, and shows the apparatus when the plotting machine in an unmodified form, is employed, in a conventional manner, in producing a first film with a single, desired, image provided thereon,
Figure 4 is an elevation of the arrangement of Figure 3,
Figure 5 indicates the apparatus adapted for employment in producing a second film with the required array of desired images provided thereon, the developed first film being repositioned on the platen, and then to be mounted on a contact printer, the contact printer being arranged to be displaced in the plotting machine in the same manner as the projector, and in the same manner as by a step-and-repeat mechanism,
Figure 6 shows the first film mounted on the contact printer,
Figure 7 shows the second film mounted on the platen,
Figure 8 shows the apparatus during employment of the contact printer, and
Figure 9, comprising a sectional elevation, shows in greater detail the arrangement of Figure 8.
A known form of plotting machine for use in producing a developed film, with an image provided thereon, is shown in
Figure 1. In particular, the developed film either comprises,or is to be employed in producing, a mask, the mask being for use in photolithographic processing, for example, of printed circuit boards. The film, in an unexposed form, is positioned in the plotting machine, and selected regions of the film selectively are exposed. The film then is removed from the plotting machine, and is developed, and the required image, corresponding to the exposed regions of the film, is provided on the film.
For convenience, the film in its developed form is shown mounted in the plotting machine of Figure 1, whereas the image would not be apparent until the film had been removed from the plotting machine, and developed. The image developed on the film, at least, corresponds to the image required to be reproduced by the mask in the photolithographic processing.
The illustrated, known, plotting machine, used in Rroducing the developed film, comprises a base plate 10, with a horizontal platen 11 for supporting the film 12, the platen being mounted on the base plate. The platen 11 is arranged to be displaceable along one, of two, horizontal, orthogonal directions by conventional means, not shown, and as indicated generally by the arrows 14. For the sake of clarity, the platen 11 is shown hatched. A light spot projector 16, also shown hatched for the sake of clarity, is mounted on a carriage, not shown in Figure 1. The projector 16 is displaceable along the other of the two horizontal orthogonal directions, also by conventional means, not shown, and as indicated generally by the arrows 18.The carriage, and hence also th projector 16, is constrained to move along the direction 18 by pinch rollers, not shown in Figure 1, mounted on two straight edges 19, with one straight edge on either side of the projector. The initially unexposed film 12 is provided with two holes 20, so as to be located precisely on the platen 11, by two dowel pins 21 provided on the platen, the dowel pins co-operating with the holes in the film.
The holes 20 in the film 12 are employed to ensure the desired registration between the developed film and means from which the desired mask is formed; and/or between the developed film and the means to be subjected to photolithographic processing by employing the developed film as the required mask.
Thus, the projector 16, and the platen 11, are displaceable relative to each other along the two orthogonal directions 14 and 18, by the conventional displacing means, not shown. The displacing means is controlled, by other means, not shown, so that selected regions of the initially unexposed film 12 traverse under the projector 16 in the required manner. The selected regions of the film selectively are exposed by the impingement of the light spot from the projector 16 onto these regions. In addition to the traversing action described above, the projector 16 is also controlled so that the light spot is switched on and off in the required manner, in producing the image to be developed on the film. The image is indicated generally at 24 in Figure 1. Subsequently, the exposed film is removed from the plotting machine, and is developed, to provide the image 24 on the film.
It is known to produce such a developed film, but having an array of a plurality of identical, desired, images provided thereon, the array, at least, corresponding to the multiple images required to be reproduced by the mask in the photolithographic processing.
Such a multiple image film can be produced by employing a plotting machine as described above in relation to Figure 1, in producing a developed, first, single image film. The developed first film is transferred to apparatus separate from the plotting machine, in which apparatus it is moved, in the required manner, relative to a second, initially unexposed, film to be provided with the array of images. The first film is moved, to be in registration sequentially with each constituent image location of the array to be provided on the second film, by a step-and-repeat mechanism included in the apparatus. When the first film is in registration with each such constituent image location, selected regions of the second film are exposed selectively by radiation passing through the developed first film in the appropriate manner.Subsequently, the exposed second film is removed from the apparatus, and developed, to provide the required array of multiple images thereon.
Desirably, the first and second films are precisely in the required registration in relation to each other at each constituent image location of the array. Inherently, such precise registration cannot be obtained, because the first film has been transferred from the plotting machine to the separate apparatus including the step-and-repeat mechanism, and inaccuracies are introduced into the multiple image film.
Alternatively, it is known, in producing the required multiple image film, to employ only the plotting machine shown in Figure 1. As shown in Figure 2, an initially unexposed film 12' is mounted on the platen 11, the film having two holes 20 to co-operate with the dowel pins 21 provided on the platen. The projector 16, and the platen 11, are displaced, relative to each other, along the two orthogonal directions 14 and 18, by the displacing means. At the location of each constituent image of the desired array, selected regions of the film 12', corresponding to a single constituent image, selectively are exposed by the light spot from the projector 16 traversing these regions, and by the projector being switched on and off in the required manner.The procedure, of selectively exposing selected regions of the film 12', is repeated, sequentially, at each of the locations of the constituent images 24 of the desired array. The projector 16, and the platen 11, are displaced, relative to each other, by the displacing means, so that the desired array of images 24 is provided. Subsequently, tne exposed film is removed from the plotting machine, and is developed, to provide the array of images on the film. Such a procedure in producing a film with the required array of images, although substantially accurate, is time consuming.
In accordance with the present invention, and as shown in Figures 3 to 9, apparatus for use in producing a multiple image mask, the mask to be employed in photolithographic processing, includes the plotting machine shown in Figures 1 and 2. The apparatus is employed in producing a multiple image film, which either comprises, or is employed in producing, the mask.
In a first stage of the operation of the apparatus, shown diagrammatically in Figure 3, the plotting machine is employed in an unmodified form, and in an conventional manner, in producing a first, developed, film 30, the first film being provided with a desired single image 24 thereon. The first film 30 differs from the film 12 of Figure 1 only in that it is not significantly larger than the desired single image 24, taking into account that the film also is provided with two holes 32 to co-operate with two dowel pins 34 provided on the platen 11. In particular, the developed first film 30 is provided in the same manner as the developed film 12 of Figure 1.
Then, as also is indicated in Figure 3, the light spot projector is removed from the plotting machine, only the carriage 36 for the projector being shown, hatched, in Figure 3.
Subsequently, the developed first film 30, which has been removed from the plotting machine so that the image 24 could be developed, is repositioned in the plotting machine.
The first film 30 is repositioned in the same registration on the platen 11 as in the first stage of the operation of the apparatus, by the holes 32 provided through the film co-operating with the dowel pins 34 on the platen. Such an arrangement is also indicated, diagrammatically, in Figure 4.
The plotting machine is capable of modification, and, in the modified form, is used in the second stage of the operation of the apparatus. The modification, which is not shown in Figures 3 and 4, not being applicable when the plotting machine is operating in a conventional manner, in producing the developed first film 30, however, is indicated diagrammatically in Figure 5, and is shown in greater detail in Figure 9.
Indicated in Figure 9 are the pinch rollers 37, by which the carriage 36 is constrained to move along the two straight edges 19.
The apparatus in accordance with the present invention has a contact printer 40, and the contact printer is mounted on an arm 42, with the arm secured to the projector carriage 36.
In the operation of the modified plotting machine, the contact printer 40 is displaceable in the same manner as the projector.
Further, the contact printer 40 is initially directly above the repositioned, developed, first film 30.
It may not be necessary for the projector to be removed from the plotting machine, after the first stage of the operation of the apparatus.
The contact printer 40 may be mounted on the arm 42 only after the first stage of the operation of the apparatus, or it may be so mounted throughout the operation of the apparatus.
The apparatus according to the present invention also has means whereby the repositioned, developed, first film 30, initially, is transferred from the platen 11, to be mounted on the contact printer 40. As indicated in Figure 5, with the first film 30 mounted on the platen 11, in precisely the same registration therewith as in the first stage of the operation of the apparatus, the dowel pins 34 are removed. The first film is then held in the required registration by a vacuum system, not shown and incorporated in the platen 11. The contact printer 40 then is moved vertically downwards to be contiguous with the first film 30. The vacuum system incorporated in the platen 11 is released, and the contact printer 40 returns to its initial position, carrying the first film 30.This movement of the contact printer 40, and the first film 30, is indicated generally by the arrows 41, and is precisely vertical.
As is shown in greater detail in Figure 9, the contact printer 40 includes a housing 50, closed at both ends. At one closed end 51 is provided a source of radiation 52, connected to an electrical supply 53 via controlled switch means, indicated generally at 54. The other end of the housing 50 is closed by a translucent plate 56.
The contact printer housing 50 is secured to the arm 42 in any convenient manner. In order that the housing can move precisely vertically, in mounting the first film 30 thereon, the arm has two constituent parts. One part 57 extends horizontally, and has the contact printer housing 50 secured thereto, and the other part 58 extends vertically from the carrage 36. Both parts 57 and 58 of the arm 42 are pivotally secured together, as indicated generally at 59, and the part 58 is rigidly secured to the carriage 36. Hence, the contact printer 40 moves vertically by a small rotational movement of the part 57, about the pivot 59.
Downward displacement of the part 57 of the arm 42 is by the action of a co-operating push-rod 60, engaging the part 57, and being displaced vertically. The push-rod 60 is moved by any convenient form of actuator, not shown, in a vertical direction, as indicated generally by the arrows 62. The downward movement of the arm part 57 is against the action of a spring 64, secured both to the- arm part 57, and to the carriage 36. Upward displacement is by the action of the spring 64.
Conveniently, upward movement of the arm part 57 is limited by a stop, not shown.
When the contact printer 40 is positioned such that the translucent plate 65 is contiguous with the first film 30, the first film is caused to be mounted on the contact printer. This is by the action of suction pads, indicated generally at 66, and secured to the housing 50 of the contact printer, so as to be distributed around the periphery of the translucent plate 56.
Subsequently, the vacuum system in the platen 11 is released, releasing the first film 30 from the platen.
As is shown in Figure 6, the contact printer 40 then returns to its initial position, being moved precisely vertically, as indicated by the arrow 68, and with the first film 30 mounted on the translucent plate 56 of the contact printer by the suction pads 66. This movement of the contact printer 40 is caused by releasing the push-rod 60, and the contact printer returns to its initial position under the action of the spring 64, the arm part 57 rotating about the pivot 59.
As shown in Figure 7, a second, initially unexposed, photographic film 70 is positioned on the platen 11, in the place of the developed, first film 30. In particular, the second film 70 is in the same registration on the platen as the first film 30 when previously so mounted, the same dowel pins 34, not shown in Figure 7, co-operating with holes, not shown, in the second film. Subsequently, the dowel pins 34 are removed, and the second film 70 is held in the required registration by the vacuum system, not shown, incorporated in the platen 11.
In producing the developed second film 70, provided with the required array of a plurality of identical images 24, the developed first film 30 is moved relative to the second film, sequentially, between each location of the constituent images of the array to be provided. Thus, in the second stage of the operation of the apparatus in accordance with the present invention, with the first film not contiguous with the second film, the displacing means, not shown, of the plotting machine is controlled to act as if the movement of the first film relative to the second film is provided by a known form of step-and-repeat mechanism,
At each constituent image location of the array to be provided, movement of the first film relative to the second film is stopped temporarily, and the first film is lowered to be contiguous with the second film.
As shown in Figure 8, the contact printer 40 is displaced vertically downwards, as indicated generally by the arrow 80, the arm part 57 rotating about the pivot 59, and so that the developed, first film 30 is contiguous with the second film 70. The height of the pivot 59 above the platen 11 is arranged to be such that the first film 30, mounted on the contact printer 40, is exactly parallel to the second film 70 mounted on the platen 11, when the first and second films are contiguous.
The radiation source 52 of the contact printer 40 then is actuated, so that selected regions of the second film 70 are exposed selectively to the radiation from the source, through the developed first film 30.
The first film 30 then is separated from the second film 70, and is displaced to another constituent image location of the array. The selected regions of the second film 70 at this image location are exposed selectively in the same manner as described above.
These actions are repeated, sequentially, until the selected regions of the second film at each constituent image location of the array have been exposed. Then the second film 70 is removed from the apparatus, and developed, to provide the desired multiple image film.
The desired multiple image film is produced more conveniently with reference to Figures 3 to 9, in the manner described above, than when produced by plotting each constituent image of the array sequentially, by the plotting machine, and as described above with reference to Figure 2, because less time of the plotting machine is employed.
The desired multiple image film is produced more accurately in the manner described above, with reference to
Figures 3 to 9, than when the developed first, single image film is transferred to separate apparatus, in order to produce the desired, multiple image second film. The increased accuracy obtained with apparatus in accordance with the present invention is because the developed first film, instead of being transferred to separate apparatus, is transferred vertically, precisely, within the sole apparatus. Further, the second film initially is mounted in the apparatus in exactly the same registration as the initial first film mounting. Thus, registration between the first and second films at each constituent image location of the required array is greater than otherwise would be the case.
Claims (2)
1. Apparatus for use in producing a multiple image mask, the mask to be employed in photolithographic processing, includes a plotting machine having a platen to support an initially unexposed photographic film, a light spot projector, and means to displace the projector relative to the platen in two orthogonal directions, in a first stage of the operation of the apparatus, in producing a single desired, image on a first film, when developed, the displacing-means is to be controlled in the appropriate way, so that selected regions of the first film are to be exposed selectively, by the light spot from the projector traversing the selected regions, and the apparatus also includes a contact printer, the displacing means of the plotting machine to displace the contact printer relative to the platen in the two orthogonal directions, in the same manner as with the projector in the first stage, in a second stage of the operation of the apparatus, initially the developed first film provided with the single image is to be located on the platen in precisely the same registration as in the first stage, and transfer means is 'provided in the apparatus whereby, subsequently, the first film is to be transferred to be mounted on the contact printer, and thereby is to be moved, initially, precisely along the third orthogonal direction, an initially unexposed, second film to be provided with an array of a plurality of identical, desired, images, is to replace on the platen, and is to be precisely in the same registration as, the first film, in the second stage tne displacing means i to be controlled in the appropriate way, so that the first film is to be moved relative to the second film, sequentially, to be in precise registration with each constituent image location of the array to be provided on the second film, with the first film in precise registration with each such location, selected regions of the second film are to be exposed selectively by employing the contact printer with the first film mounted thereon, in producing the second film with the required array of desired images provided thereon.
2. Apparatus for use in producing a multiple image mask, the mask to be employed in photolithographic processing, substantially as described herein with reference to Figures 3 to 9 of the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8804793A GB2215477B (en) | 1988-03-01 | 1988-03-01 | Apparatus for use in producing a multiple image mask to be employed in photolithographic processing |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8804793A GB2215477B (en) | 1988-03-01 | 1988-03-01 | Apparatus for use in producing a multiple image mask to be employed in photolithographic processing |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8804793D0 GB8804793D0 (en) | 1988-03-30 |
| GB2215477A true GB2215477A (en) | 1989-09-20 |
| GB2215477B GB2215477B (en) | 1991-12-04 |
Family
ID=10632609
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8804793A Expired - Lifetime GB2215477B (en) | 1988-03-01 | 1988-03-01 | Apparatus for use in producing a multiple image mask to be employed in photolithographic processing |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2215477B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2314170A (en) * | 1996-02-01 | 1997-12-17 | Lg Electronics Inc | Alignment layers for liquid crystal devices |
| US5889571A (en) * | 1996-02-01 | 1999-03-30 | Lg Electronics Inc. | Ultraviolet irradiating device for photo-alignment process and an irradiating method using the same |
-
1988
- 1988-03-01 GB GB8804793A patent/GB2215477B/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2314170A (en) * | 1996-02-01 | 1997-12-17 | Lg Electronics Inc | Alignment layers for liquid crystal devices |
| GB2314170B (en) * | 1996-02-01 | 1998-07-15 | Lg Electronics Inc | An ultraviolet irradiating device for photo-alignment process and an irradiating method using the same |
| US5889571A (en) * | 1996-02-01 | 1999-03-30 | Lg Electronics Inc. | Ultraviolet irradiating device for photo-alignment process and an irradiating method using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8804793D0 (en) | 1988-03-30 |
| GB2215477B (en) | 1991-12-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5760881A (en) | Exposure apparatus with light shielding portion for plotosensitive elements | |
| KR960024695A (en) | Exposure equipment | |
| JPH10112579A (en) | Resist exposing method and exposing apparatus | |
| US6211942B1 (en) | Double-sided exposure system | |
| US4571073A (en) | Apparatus for the exposure of photosensitive plates on two sides | |
| JPS5814757B2 (en) | Zounoseigohouhou Oyobi Sonosouchi | |
| US4203664A (en) | Film positioning apparatus | |
| US4209239A (en) | Plotting apparatus having an adjustable plotting head | |
| GB2215477A (en) | Apparatus for use in producing a multiple image mask to be employed in photolithographic processing | |
| US3797932A (en) | Vibration isolation arrangement for aperture card photographic copying machine | |
| JPS6379320A (en) | Semiconductor substrate exposure equipment | |
| US3920333A (en) | Photographic subject holder | |
| US4996763A (en) | Method of locating work in automatic exposing apparatus | |
| US3602591A (en) | Step and repeat camera | |
| JPH0469939B2 (en) | ||
| US4536470A (en) | Method and apparatus for making a mask conforming to a ceramic substrate metallization pattern | |
| US3276312A (en) | Movable vacuum back for photographic apparatus | |
| US3204520A (en) | Apparatus for manufacturing font plates for phototypographical machines | |
| US3286608A (en) | Photographic-type printing device | |
| US4322161A (en) | Stripper's table and method of compositing lithographic work pieces | |
| US3460448A (en) | Preparation of printed circuits | |
| US3740131A (en) | Device for automatically displaying and withdrawing an original positioning scale | |
| US3740138A (en) | Process camera alignment and exposure system | |
| US3717975A (en) | Apparatus for correcting printing errors | |
| EP0367234B1 (en) | Process camera |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19950301 |