JPH0850358A - Manufacturing apparatus of photoengraving plate - Google Patents

Abstract

PURPOSE: To shorten the time for making a photopolymerizable plate. CONSTITUTION: This photoengraving device 10 includes an array of light emitting devices 30a to 30n for physically or electronically scanning, exposing and solidifying optical polymers in order to manufacture a structure 16. A scanning process is controlled by software operated by a computer processor 15 and the duration and intensity of light emitted from respective devices 30a to 30n in the array are also controlled by the processor 15.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates generally to photolithographic processes used to manufacture plastic parts from liquid polymers, and more specifically to a laser array exposure apparatus for photopolymer photolithographic manufacturing apparatus. Regarding

[0002]

BACKGROUND OF THE INVENTION Photopolymers are organic materials or resins that solidify when exposed to light of a certain wavelength, such as ultraviolet light. The rate and extent of coagulation is related to polymer composition, concentration and duration of exposure. Photopolymer (or stereo) photolithography is a manufacturing process that allows the plastic structure to be made by repeatedly exposing and solidifying the photopolymer liquid to form successive layers. The pattern for the overall structure can be created by computer generated data. The structure produced by this method can be used, for example, as a mechanical prototype to verify the accuracy of new product designs or computer-aided designs. Other uses for photopolymer photoengraving include the fabrication of plastic reproductions (scaled) or casting patterns of structures that are viewed using X-ray, acoustic, magnetic or electronic imaging equipment. There is. Typically,
The speed of manufacture is an important aspect in such later mentioned applications. In that regard, the layer coagulation cycle time, and thus the overall manufacturing process time, is highly related to the exposure method used to coagulate the photopolymer.

Existing photopolymer plate making equipment used in the automotive, space, biomedical and other fields uses a gas laser that emits a single beam of ultraviolet light to expose a liquid polymer. The beam is directed by a series of precision mirrors onto the surface of the contained liquid photopolymer. The mirror is positioned in response to a series of control signals received from the digital computer. The energy of the laser beam measured at the surface of the polymer is typically 5 to 15 mW. A laser beam positioned by the computer exposes and solidifies discrete regions of the liquid polymer. After the surface layer of the polymer has solidified, the resulting solid structure is incrementally lowered into the liquid polymer. The cycle of exposing, solidifying, and lowering in this way, the layers are vertically combined,
Repeated until the entire plastic structure is complete.
The completed structure is placed in a UV oven and the liquid polymer, if any, solidifies.

A major problem with existing photopolymer platemaking equipment is that it causes only a single focused beam to scan over the surface of the liquid photopolymer during each exposure cycle, resulting in complete solidification of the entire structure. Is that it requires a fairly large number of scans. Not only is this method inefficient and costly in terms of cycle time consumed, it also requires the use of relatively complex combinatorial techniques to reduce the overall scan time. Nevertheless, the combined scan pattern results in approximately 8 of the surfaces to be solidified during the manufacturing cycle.
0% exposure may be relatively efficient, resulting in a scan time reduction of about 20%, which is achieved at the expense of structural robustness. In addition, it requires the use of a secondary oven to solidify the remaining liquid polymer. In addition, the scanning combination technique is complex, in order to transform the computer model into a suitable signal for controlling the path of the laser beam,
Highly requires specific software for each application.

Another problem that occurs with existing photopolymer platemaking equipment is that the gas laser equipment is firmly attached to the equipment envelope due to its size and delicate nature. Moreover, the precision mirrors used to direct the laser beam are relatively expensive and must be precisely aligned to produce a precisely focused beam. Typically, the last mirror in a series of precision mirrors is
A galvanometer-controlled mirror with a gimbal attached,
This directs the laser beam in a radial pattern to the plane of the photopolymer. This radial pattern causes the beam to defocus as the scan distance increases for a line drawn perpendicular to the plane of the polymer.
This defocusing results in uneven exposure of the photopolymer, which reduces the overall accuracy and tolerances of the finished structure, and limits the size of the structure that can be made.

Another problem encountered with existing photopolymer platemaking equipment is that when a large area of exposed polymer is covered by a subsequent layer of liquid polymer due to the viscous nature of the polymer liquid. It is to cause "middle and high". After each cycle, these uneven areas are flattened by sweeping the surface of the structure being manufactured horizontally with a bar. However,
The time required to level such uneven areas prolongs the overall time of the manufacturing process.

[0007]

Therefore, there is a need in the photopolymer plate making industry for a more efficient and flexible photopolymer exposing device. The present invention provides a photolithographic fabrication apparatus that includes an array of light emitting devices that physically or electronically scan, expose, and solidify a surface of a photopolymer to fabricate a structure. The scanning process is controlled by software running on the processor, and the duration and intensity of the light emitted from each individual light emitting device in the array is also controlled by the processor.

In order that the invention and its advantages may be better understood, the following description refers to the drawings.

[0009]

The preferred embodiment of the present invention and its advantages are best understood by referring to FIGS. 1-4. Like numbers refer to like parts throughout the drawings.

FIG. 1 shows a perspective view of a solid state laser scanning array photopolymer plate making apparatus constructed in accordance with the preferred embodiment of this description. The photopolymer plate making apparatus of the present invention is shown generally at 10 and may include, for example, a digital manufacturing control unit comprising a digital processor unit 15, a display unit 12 and a keyboard 14. However, although a digital manufacturing controller is shown in FIG. 1 as an example, the invention is not so limited. For example, the digital controller shown in FIG. 1 may be replaced with a programmable controller. The processor device 15 includes a CPU, a RAM, a ROM, a mass storage device, and an I / O.
It may include the O portion, as well as a typical personal computer or other component of a general purpose computer system. Appropriate standard application software can be run on the processor unit 15 to generate control data that can be used to create a three-dimensional polymer or plastic structure during the manufacturing process.
For example, a professional engineer developed by Parametric Technologies Corporation to generate an STL file of digital data representing a three-dimensional structure to be formed using the photopolymer plate manufacturing method of the present invention in a universal format. -Standard CAD software such as software can be used.

Generally speaking, control data from the processor unit 15 may be coupled to the scanning mechanism 20.
The scanning mechanism contains a solid-state laser array and / or a plurality of optical fibers that are used to expose and solidify the liquid photopolymer. In response to the control signal received from the processor unit 15, the scanning mechanism 20 including the laser array can be positioned over a predetermined area of the polymer to be exposed.

Specifically, in the embodiment shown in FIG.
The liquid photopolymer can be kept in the tank 26.
Under control of the signals received from the processor unit 15, a device consisting of a vertical threaded gear and a threaded follower (not shown) causes the support platform 18 to move into the liquid polymer inside the tank 26. Can be lowered at a predetermined speed or by discrete steps. The screw gear device can be rotated and operated by a series of digital or analog motors. Also under the control of the processor unit 15, the scanning device 20 is horizontally directed onto the surface of the liquid polymer by means of a pair of horizontal screw gears 22 and a threaded follower 24 for solidifying the liquid polymer. Can be moved to. The screw gear 22 can also be operated and rotated by a series of digital or analog motors in response to control signals from the processor unit 15. In general, an array of solid state semiconductor laser devices (discussed in detail below) housed within the scanning device 20 emits a predetermined pattern of light in the ultraviolet range, which causes the array of tanks 16 to illuminate. As it traverses the surface horizontally, the outermost layer of liquid polymer is exposed and solidified. Prior to each horizontal scan cycle, processor unit 15 causes support platform 18 to
To generate a control signal which directs it to descend vertically into the liquid polymer by a predetermined incremental amount. Thereafter, processor unit 15 generates an appropriate control signal directing scanning mechanism 20 to horizontally traverse the tank for scanning and exposing the polymer region to be solidified. The layers of solidified polymer thus obtained are vertically combined or stacked to create a replica of a computer-defined structure or image.

FIG. 2A is a perspective view of the scanning mechanism 20 shown in FIG. In the embodiment shown in FIGS. 1 and 2A, the scanning mechanism 20 may include, for example, the lower surface 28, which may be slightly arcuate. As shown, the 1 × n array of light emitting semiconductor laser devices 30a-30n can be arranged in a row along the central portion of the lower surface 28. Laser device 30a
-30n is coupled to the support structure 32 so that each laser 30
The emission surface of a-30n may be flush with the lower surface 28. However, while the solid-state laser arrays 30a-30n shown in FIG. 2A are shown as a 1 × n array by way of example, the invention is not limited to a particular number of columns in such an array. Please understand that.
For example, such an array may have three rows of semiconductor lasers arranged side by side. In essence, the number of rows in the multi-column array 30a-30n (where the value of'a 'may be a variable here) is a design constraint.
May be limited by the dimensions of.

Each of the semiconductor devices 30a-30n may be a semiconductor laser device based on silicon or gallium arsenide. With each of these devices 30a-30n, output energy levels of up to about 1 W can be generated. The output energy of each individual device 30a-30n
The level can be selectively controlled by a control signal received from the processor unit 15. Although each semiconductor device 30a-30n shown in FIG. 2A is shown as having a single light emitting surface, this is also for purposes of illustration only and is not intended to be limiting. For example,
Each semiconductor device 30a-30n may have two or more light emitting surfaces, depending on the technology used.
Further, the idea of the invention is not intended to be limited to any particular type of light source, but any suitable light source that projects a light pattern to expose the solid state semiconductor device 30a-30n to solidify the photopolymer resin material. Any form of "flat panel" with
Alternatively, it may be replaced with another display device. For example, a suitable plasma display, liquid crystal display, negative curve tube display or light emitting diode display can be used in place of the solid state semiconductor laser devices 30a-30n. In addition, one or more monolithic micromechanical spatial light modulators (SLMs) manufactured by Texas Instruments Incorporated, having microminiature discrete tilt mirror elements on an integrated circuit chip. ) Can be used in place of devices 30a-30n to project light from the source to solidify the photopolymer. Further, it is noted that some resins cure through exposure to light energy in the infrared or visible wavelengths. Thus, depending on the composition of the resin used, the array can include exposure devices that operate at frequencies outside the UV range.

For example, when using a plasma display device as a light source, an array of gas discharge columns energizes an array of phosphor dots to emit a pattern of light at an appropriate wavelength to expose the photopolymer. Can be cured. The wavelength of the emitted light is determined by the type of gas used in the discharge column. Alternatively, the light pattern can be generated directly by an array of energized gas discharge columns without the use of phosphor dot arrays.

As another example, when a liquid crystal display device is used as a light source for exposure, the light source operating at an appropriate wavelength can be configured as a backlight of the array. Under control of the voltage received from the processor device 15, the liquid crystal display device can be selectively polarized to project a predetermined pattern of light to expose and solidify the photopolymer resin.

Another advantage of the preferred embodiment shown in FIGS. 1 and 2A is that the scanning mechanism 20 has a flattened polymer surface feature. Specifically, the edges 29a, 29 of the lower surface 28
Both b define a straight edge and can be swept horizontally across the exposed polymer surface, which has a "middle-high" effect to flatten the uneven surface of the polymer. it can. Since these straight edges 29a, 29b can be formed as an integral part of the scanning mechanism 20, the polymer surface flattening cycle can be performed simultaneously with the exposure cycle, which produces each structure. Significantly reduces the overall time it takes to do.

FIG. 2B is a cutaway view showing the laser array emitting portion of the scanning mechanism 20 shown in FIG. 2A in greater detail. Solid-state semiconductor device 30a-each including one light emitter
30n may be coupled to the support structure 32. Connect each pair of conductive leads 34a-34n to the emitters 30a-30.
n can be connected to selectively supply power to power each emitter. Leads 34a-34n can be connected to the analog output connections of a digital-to-analog converter (not shown). The input connection of the analog-to-digital converter can be connected to the digital I / O part of the processor unit 15. Thus, under the control of application software operating on the processor unit 15, the processor unit 15 selectively controls the output energy of each photoemitter 30a-30n, thus causing the units 30a-30n to polymerize. The extent and rate of exposure of the liquid polymer as it is scanned across the surface can be selectively controlled to provide an appropriate pattern of light exposure, depending on the dimensions of the structure being manufactured.

FIG. 3 is a perspective view of the second embodiment of the present invention. In this aspect of the invention, scanning mechanism 20 may include a multi-dimensional array (eg, m × n array) of solid state semiconductor laser devices 40a-40n mounted on sidewall 43 of scanning mechanism 20. Each semiconductor device 40a-40
The n light emitting portions can be coupled (using standard fiber optic coupling techniques) to respective optical fibers 42a-42n. Each optical fiber 42a-42n may act to retransmit or relay the light received from the respective emitter 40a-40n. The optical fibers 42a-42n may be coupled to the support structure 32 in a single row (or in multiple rows similar to the array described with respect to FIG. 1). A plurality of holes may be drilled, machined or otherwise formed in the support structure 32 to allow the light emitting ends of the optical fibers 42a-42n to pass therethrough and be flush with the lower surface 28. Therefore, each semiconductor laser device 40a
The light emitted by the optical fiber 42a-4
It can be transmitted again from 2n to form a suitable exposed pattern that is directed to the photopolymer in tank 26. Similar to the power control operation described for semiconductor devices 30a-30n shown in FIGS. 1 and 2B, each device 40a-40
n power levels and on / off times, and thus the optical energy emitted from each optical fiber 42a-42n,
It can be selectively controlled by a data signal received from the processor unit 15. An important advantage of using fiber optic arrays is that each fiber carries a very narrow, highly focused beam of light energy, which allows the entire array to have a high resolution exposure light pattern. Is that it can occur.

FIG. 4 is a perspective view of the third embodiment of the present invention. A fixed array photopolymer plate making apparatus constructed in accordance with the teachings of the present invention is shown generally at 50 in FIG. Similar to the embodiment shown in FIG. 1, the liquid photopolymer to be exposed and to be solidified can be placed in a tank 26. Under control of the signals received from the processor unit 15, the support platform 48 (shown in the elevated position) is driven into the photopolymer contained in the tank 26 at a predetermined or incremental rate. It can be lowered in steps. A two-dimensional array of solid state semiconductor devices 46a-46m may be mounted on lid 44 of tank 26 (illustrated in an open, non-operative position for purposes of illustration). Each of the semiconductor devices 46a-46m arranged on the lid 44 is
Light energy in the ultraviolet part of the frequency spectrum can be emitted. The array attached to lid 44 is normally operated with lid 44 in the closed or lower position (not shown). Under the control of the data signal received from the processor device 15, a plurality of semiconductor devices 46a
A suitable 3 for selectively energizing -46m to simultaneously emit light, thus exposing and solidifying the liquid photopolymer.
Dimensional light patterns can be formed. Similar to the embodiment shown in FIG. 1, prior to each scan and exposure cycle, processor unit 15 causes support platform 48 to
A signal can be transmitted to the liquid polymer to instruct it to descend a predetermined amount. The advantage of the embodiment shown in FIG. 4 is that
That is, the scanning can be done electronically rather than mechanically. In particular, this reduces the complexity of the manufacturing process and reduces the overall manufacturing time.

Generally speaking, the scanning mechanism shown in FIGS. 1-3 can be moved horizontally across the surface of the liquid photopolymer under the control of the data signals received from the microprocessor. By controlling the power levels as well as the on / off times of the individual solid state semiconductor devices in the array attached to the scanning mechanism, standard application software running on a microprocessor can generate the light pattern. The light pattern can expose specific areas of the photopolymer, and thus the specific areas can solidify to form specific shapes. After this, the platform supporting the structure being formed can be lowered into the liquid polymer by a predetermined amount, after which the scanning and exposing process can be repeated. The scanning and exposing process can be continued until the complete structure is formed. The platform is then lifted from the completed polymer structure from the tank. Alternatively, the scanning and exposing steps can be performed electronically, instead of mechanical scanning, using a two-dimensional array of solid state semiconductor lasers. As a further alternative, the scanning mechanism concept of the present invention may include subsurface exposure of the polymer. For example, the one-dimensional scanning mechanism of the present invention can be lowered into the photopolymer and repositioned vertically when the exposure cycle is complete. Therefore, the scanning mechanism of the present invention can also solidify the polymer on the surface other than the surface along the horizontal plane. In other words, the scanning mechanism of the present invention can be used to replicate the structure by scanning up and down in the tank or from one side to the other.

The mechanical and electronic scanning of the present invention has numerous advantages over existing photolithographic manufacturing techniques. For example, when compared to a single source device, the scanning array of the present invention increases process accuracy or fidelity (ie, tighter design tolerances in the resulting structure) and overall process time. Shorten and increase the capacity of the entire device. Moreover, the use of solid state devices in the array of the present invention instead of the relatively expensive and cumbersome gas lasers simplifies the control of the exposure process, reduces costs and increases the overall reliability of the device. It is advantageous.

Specifically, compared to a single light source exposure device, the one-dimensional array (one row of light sources) of the present invention has a time reduction factor equal to the length of the array divided by the diameter of the beam. Thus, the unit area of the polymer can be solidified. The two-dimensional array of emitters of the present invention is capable of solidifying a unit area of polymer with a time reduction factor equal to the area of the array divided by the area of the light beam. For example, assuming that one inch square area of polymer is to be solidified, an existing single laser source that scans a 0.01 diameter beam at a rate of 10 inches per second solidifies a one inch square area. It takes about 10 seconds to get it done. With the one-dimensional scanning array of the present invention, the time required for solidifying the same area is about 0.1 seconds (time reduction ratio is 100: 1). With the two-dimensional scanning array of the present invention, That time is about 0.001 seconds (time reduction rate is 10,000: 1). Moreover, when used at least once, the two-dimensional array of the present invention can be used to "flash" expose an entire area of polymer at one time, further reducing processing time significantly.

The scanning array of the present invention replicates a highly accurate structure from a computer model as compared to existing devices. This is primarily because the light emitting surfaces of the array of the present invention are coplanar and each light emitting surface is at an equal distance from the coplanar surface of the photopolymer and This is because it is relatively uniform.

The scanning array of the present invention is much smaller and can be much smaller than existing devices. For example, the dimensions of the structure to be made determine the distance that the gimbaled mirror in existing equipment must be away from the plane of the structure. In order to achieve reasonable accuracy when exposing a 6x9 inch section, existing gimbaled mirrors should be placed about 30 inches above the plane of the section. Since the array of the invention can be placed closer to this part (because of the higher resolution beam used), the photomechanical system of the invention can be much smaller than existing systems.

Although the present invention and its advantages have been described in detail, it should be understood that various changes can be made to the contents described above without departing from the scope of the invention defined by the claims.

Further, the following items will be disclosed.

(1) A container that can act to contain a photopolymer and each light emitting device can act to emit light energy in a predetermined direction.
In response to an m × n array of light emitting devices in which the emitting surface of the array is coplanar with the surface of the photopolymer, and a pattern intended to represent the structure to be produced by the photolithographic production apparatus, A processor capable of generating a first plurality of control signals operable to selectively control the output energy level of each of the light emitting devices of the array.

(2) In the photoengraving manufacturing apparatus according to claim 1, the m × n array further has a 1 × n array,
A scanning device having the 1xn array fixedly mounted, the scanning device and the 1xn array responsive to a second plurality of control signals generated by the processor; and A photomechanical manufacturing apparatus operable to move across the surface of the photopolymer according to the predetermined pattern.

(3) The photolithography manufacturing apparatus according to claim 2, wherein the scanning device can move horizontally across a horizontal plane of the photopolymer.

(4) The photolithography manufacturing apparatus according to claim 1, wherein the plurality of light emitting devices include a plurality of solid-state semiconductor laser devices.

(5) In the photoengraving manufacturing apparatus according to claim 1, the processor is a digital computer.
A photolithography manufacturing system consisting of a processor.

(6) The photolithography manufacturing apparatus according to claim 1, wherein the light energy is ultraviolet energy.

(7) The photolithography manufacturing apparatus according to claim 1, further comprising a plurality of optical fibers, each of the plurality of optical fibers being coupled to a respective light emitting device of the array. A photo of which the emitting surface of each optical fiber is flush with the surface of the photopolymer. Plate making equipment.

(8) A container capable of acting to contain a photopolymer and a 1 × n array of light emitting devices are provided, and each light emitting device of the 1 × n array emits light in a predetermined direction. It is designed so that it can act so as to release energy.
The scanning device is oriented such that the emission surface of the xn array is coplanar with the surface of the photopolymer and, in response to a predetermined pattern representing the structure to be produced by the photolithographic production apparatus. A digital processor operable to generate one plurality of control signals and a second plurality of control signals, the first plurality of control signals for each of the 1 × n arrays. The second light source is operable to selectively control the output energy level of the light emitting device, and
A plurality of control signals for controlling the movement of the scanning device and the 1 × n array across the face of the photopolymer to act to solidify the face of the photopolymer. .

(9) The photomechanical manufacturing apparatus according to claim 8, wherein the scanning device contacts the surface of the photopolymer after being exposed by at least one light emitting device of the 1 × n array. A photolithography manufacturing apparatus having a surface leveling mechanism capable of acting to flatten the surface.

(10) In a method of exposing a photopolymer in a photolithography manufacturing apparatus, a plurality of control signals are generated in response to a software model of a structure to be manufactured, and the plurality of control signals are generated. In response to moving the m × n array of light emitting devices across the coplanar surface of the photopolymer and in response to the plurality of control signals, the light output of each of the light emitting devices. A method comprising the step of selectively controlling

(11) In the method according to claim 10,
The method wherein the m × n array comprises a 1 × n array.

(12) Photolithography manufacturing apparatus (10, 5
0) comprises an array of light emitting devices (30a-30n, 46a-46m) that physically or electronically scan, expose and solidify the photopolymer to produce structure (16).
The scanning process is controlled by software running on the computer processor (15) and each individual light emitting device (30a-30n, 46a-46) in the array.
The duration and intensity of the light emitted from m) is also controlled by the processor (15).

[Brief description of drawings]

FIG. 1 is a perspective view of a solid-state laser scanning array photopolymer plate-making apparatus constructed according to a preferred embodiment of the present invention.

FIG. 2A is a perspective view of the scanning mechanism shown in FIG. B is Figure 2
3 is a cutaway view showing details of a portion of the laser array of the scanning mechanism shown in FIG.

FIG. 3 is a perspective view of a second embodiment of the present invention.

FIG. 4 is a perspective view of a third embodiment of the present invention.

[Explanation of symbols]

 15 processor device 16 structure 20 scanning mechanism 26 tank 30a-30n, 40a-40n semiconductor laser device

Claims (2)

[Claims] 1. A container capable of acting to contain a photopolymer, and each light emitting device capable of acting to emit light energy in a predetermined direction. In response to an m × n array of light emitting devices, the emission surface of which is coplanar with the surface of the photopolymer, and a pattern intended to represent the structure to be produced by the photolithographic production apparatus. A photoengraving machine having a processor operable to generate a first plurality of control signals operable to selectively control an output energy level of each of the light emitting devices. 2. A method of exposing a photopolymer in a photolithography manufacturing apparatus, wherein a plurality of control signals are generated in response to a software model of a structure to be manufactured, and the plurality of control signals are generated. In response, the m × n array of light emitting devices is moved across the coplanar surface of the photopolymer, and the light output of each of the light emitting devices is responsive to the plurality of control signals. A method comprising the step of selectively controlling.