JP4036367B2 - Method and apparatus for forming resin film - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a resin film forming method and apparatus suitable for forming a resin film having a substantially uniform thickness between or on substrates of an optical disk such as a DVD.
[0002]
[Prior art]
In general, an optical disc such as a DVD basically has a structure in which two transparent substrates are bonded together with an adhesive. In this case, there are substrates in which a recording layer including a reflective layer or a semi-transmissive film is formed on only one substrate, or a recording layer is formed on both substrates, and a recording layer is formed only on one substrate. In the case of being formed, both substrates have the same thickness, or the substrate on which the recording layer is not formed has a thin transparent sheet as a light transmission protective layer. Further, there is a structure in which four substrates are laminated by bonding two members having such a bonding structure through an adhesive. Another example is a case where a plurality of transparent glasses or lenses are bonded together with an adhesive.
[0003]
In such a case, in an optical disk such as a DVD, after two substrates are stacked via an adhesive, the adhesive is spread evenly between the substrates by rotating at high speed, and then the excess adhesive is shaken off. Generally, the adhesive is cured in a short time by irradiating ultraviolet rays from one side or both sides of the substrate. The ultraviolet irradiation is performed by continuously irradiating ultraviolet rays for a predetermined time using a UV lamp, or by irradiating ultraviolet rays in a pulse manner using a xenon lamp.
[0004]
[Problems to be solved by the invention]
However, in any case, the curing method using these lamps, after superposing two substrates via an adhesive, is rotated at a high speed to spread the adhesive between the substrates and shake off excess adhesive. Then, since the adhesive is cured in a short time by irradiating ultraviolet rays from one side or both sides of the substrate, the adhesive layer is not actually uniform, and the curves A and B in FIG. As shown, there is a problem that the film thickness on the outer peripheral side becomes thicker than the inner peripheral side of the substrate. Here, the curve A indicates that the substrate is rotated at 3,000 rpm. p. m. Shows the film thickness characteristics when the substrate is rotated for 13 seconds, and curve B shows that the substrate is 3,000 rpm. p. m. The film thickness characteristics when rotated for 20 seconds are shown.
[0005]
In either case of the curves A and B, the maximum difference in the thickness of the adhesive layer is about 8 μm, which is quite large, which is a problem in further improving the quality of the current DVD. As shown by curve A and curve B in FIG. 10, when the inner peripheral film thickness is adjusted to the predetermined value, the outer peripheral film thickness is increased, and when the outer peripheral film thickness is adjusted to the predetermined value, the inner peripheral film thickness is increased. The film thickness becomes thin. That is, it is impossible to make the thickness of the adhesive layer uniform regardless of how the rotation time or the number of rotations is adjusted.
[0006]
In particular, in a next-generation large-capacity optical disc called a Blu-ray Disc (A Blu-ray Disc) or an AOD (Advanced Optical Disc), the non-uniformity of the thickness of the adhesive layer becomes a serious problem.
[0007]
In the Blu-ray Disc, the thickness of the light transmission protective layer consisting of the adhesive layer and the sheet or the light transmission protective layer consisting only of the transparent resin layer is as thin as 0.1 mm. The non-uniformity has a great influence and greatly affects the quality of the next generation large capacity optical disk.
[0008]
In the case of AOD, both substrates to be bonded are 0.6 mm in thickness, which is the same as that of a normal DVD, but the thickness of the adhesive for bonding them is made uniform with sufficiently high accuracy. In any case, the uniformity of the adhesive thickness greatly affects the quality of the next-generation large-capacity optical disk.
[0009]
In order to solve such a conventional problem, the present invention irradiates a light beam from the inside of the substrate toward the outside of the radiation in a process in which the liquid material is spread by high-speed rotation. By shifting and hardening or semi-curing sequentially from the inner circumference side to determine the thickness, the liquid material at the location where the thickness has become almost a predetermined thickness moves outward in the radial direction by subsequent high-speed rotation. This is to prevent the film thickness of the liquid material from being uniform on the entire surface of the substrate.
[0010]
[Means and Actions for Solving the Problems]
  In the present invention, the step of spreading the liquid material supplied in an annular shape to the center side of the substrate by high-speed rotation and the step of rotating at low speed are alternately performed a plurality of times, and from the center side toward the outer peripheral side during the low-speed rotation. In this method, the liquid material is sequentially semi-cured or cured from the inner peripheral side by sequentially shifting the irradiation of light rays.
[0011]
  According to the present invention, the liquid material is spread during high-speed rotation, and light is irradiated when the liquid material is not substantially spread, so that the portions having a predetermined thickness are sequentially cured or semi-cured. Since the thickness is determined, the film thickness can be made more uniform, and a light emitting means with low light emission energy can be used, and the thermal influence on the substrate can be reduced.
[0040]
[Embodiments of the Invention]
Before describing the embodiments of the present invention, first, the basic concept of the present invention will be described. FIG. 1 shows two polycarbonate substrates 1A and 1B arranged opposite each other before being superposed, and one substrate 1A is supplied with an adhesive 1C as a liquid material in a donut shape, that is, in an annular shape. When the substrates 1A and 1B are overlaid, the position of the adhesive is not different from the position supplied to the substrate 1A. When high-speed rotation is started, the adhesive 1C spreads from the inner periphery to the outer side due to the centrifugal force.
Accordingly, in the present invention, there is a time when the adhesive layer has a desired thickness in the process of the adhesive 1C moving to the outer peripheral side by high-speed rotation, and at that time, the light beam is sequentially applied to the adhesive layer from the inner periphery to the outer periphery. The knowledge that it is possible to form a resin film with a substantially uniform thickness by irradiating and semi-curing or curing so that the adhesive layer does not move to the outer peripheral side by centrifugal force due to subsequent high-speed rotation. Is based. This also applies to the case where a resin film made of a liquid material is formed on a single substrate, and the above knowledge can be applied. A curve C in FIG. 10 shows an example of a film thickness characteristic when the present invention is applied.
[0041]
Hereinafter, a resin film forming method and apparatus having a uniform film thickness according to the present invention will be described with reference to the drawings. First, a first embodiment in which an optical disk is bonded using a mechanical shutter and an irradiation lamp will be described with reference to FIGS. 2 shows an initial state of the irradiation opening of the mechanical shutter, and FIG. 3 shows a final enlarged state of the irradiation opening of the mechanical shutter.
[0042]
Both substrates 1A and 1B have a central hole X, where the central hole X side is referred to as the inner peripheral side, and the outer peripheral end Y side is referred to as the outer peripheral side. When the recording layer including the reflective film is formed only on one of the substrates, the recording layer is not formed on the substrate 1B, and the recording layer including the reflective film is formed on the substrate 1A. When recording layers are formed on both substrates, a recording layer including a semi-transmissive film is formed on the substrate 1B, and a recording layer including a reflective film is formed on the substrate 1A. After the substrate 1A and the substrate 1B supplied with the adhesive 1C are superposed to form the substrate 1, it is placed on the substrate holder 3 of the spinner 2 with the substrate 1B side up. The spinner 2 is a normal one, and the substrate cradle 3 can be rotated at a high speed up to several thousand revolutions or more.
[0043]
A mechanical shutter 5 is disposed immediately above the coater house 4 of the spinner 2, and an irradiation lamp 6 such as a discharge lamp or a xenon lamp is provided thereon. The mechanical shutter 5 may have a mechanism in which the central irradiation port 5A opens continuously or in stages. As an example of the application of a camera shutter, although not shown in detail, a plurality of metal plates are arranged in a partially overlapping manner, and each metal plate is moved continuously or stepwise in the radial direction at the same speed. By doing so, the central hole to be the irradiation port 5A is expanded continuously or stepwise. By sequentially expanding the irradiation port 5A, the irradiation of the ultraviolet rays from the irradiation lamp 6 gradually spreads from the inner peripheral side to the outer peripheral side of the substrate 1.
[0044]
The mechanical shutter 5 is driven by a shutter driving device 7 such as a small cylinder for moving each metal plate forward or backward in the radial direction. The shutter driving device 7 is controlled by a signal from the shutter control device 8. The control device 8 includes a CPU (not shown) and the like, and data obtained from a great number of experiments is stored in advance in the memory.
[0045]
The data includes the rotational speed of the spinner 2, the viscosity of the adhesive 1C to be used, the characteristics such as wettability to the substrate, the spreading speed of the adhesive corresponding to various conditions such as the temperature and humidity of the surrounding atmosphere, that is, an annular shape. 1C shows the relationship between the position in the radial direction in which the adhesive 1C supplied to the film has a set film thickness and time. With this data, after the start of high-speed rotation, the time at which the adhesive layer has a set thickness at each point in the radial direction of the substrate can be obtained. Therefore, by inputting the various conditions to a CPU (not shown), the optimum enlargement speed of the irradiation port 5A of the mechanical shutter 5 can also be obtained.
[0046]
In this embodiment, an irradiation lamp 6 having a large ultraviolet irradiation energy generally used in the field of manufacturing optical disks is used, and the irradiation port 5A of the mechanical shutter 5 is shown in FIG. 3 from the initial state shown in FIG. Thus, since it is continuously extended to the final enlarged state, the adhesive layers can be sequentially cured without substantially reducing the high speed rotation speed of the spinner 2 from the normal speed. In order to reduce the thermal effect on the substrate, etc., by adjusting the UV energy and irradiating, when a part of the adhesive layer is semi-cured, it can be cured in the next step as in the conventional device. It ’s fine.
[0047]
As another embodiment, the mechanical shutter 5 that can continuously open as described above may be operated stepwise. In a substrate having a radius of 60 mm, with the irradiation port 5A of the mechanical shutter 5 closed, the substrate 1 is rotated at a high speed to spread the adhesive 1C, and the mechanical shutter 5 is temporarily stopped at a position corresponding to a radius of 30 mm or 45 mm. Even if the ultraviolet ray is irradiated to a width of about 2 mm before and after the radius of 30 mm or 45 mm as the center, there is an effect of making the adhesive layer uniform. For example, when ultraviolet rays are irradiated in a state of low-speed rotation at respective positions including radii of 20 mm, 30 mm, and 45 mm after high-speed rotation, the adhesive layer is uniform as shown by curve C in FIG. The maximum film thickness difference is about 2 μm, which is about 1/4 of the conventional one. Further, it has been confirmed that the adhesive layer existing in the radial inward direction of the semi-cured or cured adhesive layer does not move in the radial outward direction even by a centrifugal force due to the subsequent high-speed rotation. The rotational speed is not limited, but in many cases 1,000 to 10,000 r. p. m. It is adjusted in the range. In particular, when the rotational speed is high, the rotational speed is 200 to 500 r. p. m. It is preferable to reduce to a certain extent.
[0048]
Next, an embodiment using a mechanical shutter of another mechanism will be described with reference to FIG. 4A shows a state viewed from the upper surface of a part of the mechanical shutter 5, FIG. 4B shows a state in which the slit portion forming the irradiation port is closed, and FIG. 4C shows the irradiation port. The state which the slit part opened is shown.
[0049]
The mechanical shutter 5 of this embodiment includes a lower disk-shaped fixed shutter member 5A in which blind portions a and slit portions b are alternately provided on the same circumference, and a plurality of annular members each having a certain width. The metal plate is a combination of a plurality of movable annular shutter members 5B provided with blind portions a ′ and slit portions b ′ alternately on the same circumference. The plurality of movable annular shutter members 5B are arranged concentrically with each other.
[0050]
The fixed shutter member 5A is divided into a plurality of circumferential regions 51, 52,... Having a certain width, and an annular small guide member 5C is provided at a position where these are divided. The guide member 5 </ b> C guides the movable annular shutter member 5 </ b> B so as not to be detached so as not to hinder the circumferential operation. The number of the circumferential regions 51, 52,... Is two or more, and is often determined in the range of five or less from the viewpoint of cost. In this case, the interval between adjacent circumferential regions is widened.
[0051]
Each of the circumferential regions 51, 52,... With a constant width has rectangular slit portions b having a circumferential length L and a radial width W at regular intervals. The area between the slit part b and the adjacent slit part b is the blind part a, and the interval between the slit part b and the slit part b, that is, the length of the blind part a is longer than the length L of the slit part b. Somewhat larger.
[0052]
Each of the circumferential regions 51, 52,... Of the fixed shutter member 5A has a blind portion a ′ and a slit portion b ′ that are approximately the same size as the blind portion a and the slit portion b. Each of the movable annular shutter members 5B is provided, and each movable annular shutter member 5B can move clockwise and counterclockwise by a distance substantially equal to one slit portion b ′ according to the guide member 5C.
[0053]
Therefore, according to the mechanical shutter 5, the movable annular shutter member 5B located on the innermost peripheral side is sequentially operated from the movable annular shutter member 5B located on the outermost side, so that the slit portion b 'matches the slit portion b. If the irradiation port is opened, light irradiation can be sequentially shifted from the inner peripheral side to the outer peripheral side. The timing for sequentially operating the movable annular shutter member 5B located on the innermost side to the movable annular shutter member 5B located on the outermost side is that the adhesive is spread by the centrifugal force after the start of high-speed rotation, and radiation of the substrate It is preferable to operate at almost the same timing as the speed at which the thickness of the adhesive layer is set at each point in the direction. In an actual device, there is a delay in the operation of the mechanical shutter 5 and the driving device 7, and the driving timing is determined in consideration of these.
[0054]
The operation of the movable annular shutter member 5B is performed by the shutter driving device 7 and the shutter control device 8 shown in FIGS. The shutter driving device 7 is composed of a combination of a cam and a motor (not shown), or a plurality of small cylinder devices, and opens or closes the irradiation port by moving it by one slit in the circumferential direction. be able to. The movable annular shutter member 5B having the slit portion b 'aligned with the slit portion b' to open the irradiation port may be left as it is, or the irradiation port may be closed after a predetermined time has elapsed.
[0055]
In this embodiment, ultraviolet irradiation is intermittent from the inner side to the outer side of the substrate, that is, discontinuous in the radial direction, and also discontinuous in the circumferential direction. Since the adhesive layer of the part is semi-cured or cured, it has been confirmed that the non-irradiated part of the adhesive layer around the part is not moved by centrifugal force. In order to make this more reliable, the lengths of the blind part a and the slit part b of the fixed shutter member 5A and the blind part a 'and the slit part b' of the movable annular shutter member 5B are appropriately reduced to a large number. What is necessary is just to provide. In addition, it is preferable to dispose the blind portions a and the slit portions b of the fixed shutter member 5A alternately in the radial direction because the movement of the adhesive layer portion not irradiated with ultraviolet rays can be suppressed without problems.
[0056]
Next, the embodiment shown in FIG. 5 includes a cooling mechanism and a wavelength selection filter for reducing the thermal influence on the mechanical shutter 5 and the substrate 1 as described above. A wavelength selection filter 9 that cuts a specific wavelength such as an infrared wavelength is provided between the discharge lamp 6 ′ capable of continuously generating ultraviolet rays and the mechanical shutter 5, and the heat-resistant glass 10 includes the mechanical shutter 5 and the spinner 2. Between. These are opened in the left-right direction of the drawing and closed in the front-back direction of the drawing so as to form a wind tunnel surrounding the mechanical shutter 5, and the cooling air flows from the left to the right as indicated by the arrows in the drawing.
[0057]
Even if the mechanical shutter 5 is made of an aluminum plate with relatively good light reflection, the temperature of the mechanical shutter 5 becomes considerably high during repeated operations, which may adversely affect the operation. In this case, the substrate 1 may be greatly affected, causing undesirable distortion or increasing the tilt. Therefore, in this embodiment, the wavelength selective filter 9 that cuts a specific wavelength such as the infrared wavelength is used as a member constituting the wind tunnel, thereby removing the infrared rays that become heat and effectively flowing the cooling air so that the mechanical shutter 5 is moved. The wavelength selection filter 9 is also cooled at the same time as it is effectively cooled. Therefore, in this embodiment, the influence of heat on the substrate 1 can be reduced. Note that the wavelength selection filter 9 may be a heat-resistant glass plate only for forming a wind tunnel. Since the operation of the mechanical filter 5 is the same as that of the above embodiment, the description is omitted.
[0058]
Next, another embodiment of the present invention will be described with reference to FIGS. This embodiment is characterized in that the thermal influence on the substrate is almost completely eliminated by using a light emitting lamp in which a plurality of light emitting semiconductor elements such as light emitting diodes or laser diodes are arranged concentrically. The same symbols as those shown in FIGS. 2, 3, and 5 indicate the corresponding members. The feature of this embodiment is that the spread of the adhesive by high-speed rotation and the spread interruption are repeated alternately, and the spread adhesive part is semi-cured by irradiating with light when the spread is interrupted. The purpose is to repeatedly spread the adhesive to a predetermined thickness from the circumferential side to the outer circumferential side and to perform semi-curing thereof repeatedly. Here, the light beam means light having a wavelength band effective for the curing reaction of the adhesive or resin used.
[0059]
As shown in FIG. 6, a semiconductor light emitting lamp 11 is disposed immediately above the substrate 1. As shown in FIG. 7, the semiconductor light-emitting lamp 11 includes a large number of light-emitting diodes 11a as light-emitting semiconductor elements and a support body 11b that supports them. In this embodiment, a large number of light emitting diodes 11a are arranged close to each other, and are attached to the support body 11b so that the light emitting surfaces H of the large number of light emitting diodes 11a are all in the same plane. The arrangement of the plurality of light emitting diodes 11a is preferably concentric. Although the majority of these light emitting diodes 11a are not shown, when adjacent ones are provided in contact with each other, about 350 to 450 light emitting diodes 11a constitute one light emitting lamp. These light emitting diodes 11a are preferably connected in parallel. However, the light emitting diodes do not necessarily have to be on the entire surface, and may be arranged so as to form a part of the entire circumference, for example, a 120-degree fan shape. Further, there may be a gap between the annularly arranged light emitting diodes adjacent in the radial direction, for example,
A plurality of light emitting diodes in an annular arrangement may be provided at intervals.
[0060]
The cathode side of each light emitting diode 11 a is connected to the negative electrode of the DC power supply 12, and the anode side thereof is connected to the positive electrode of the DC power supply 12 via the protective resistor 13 and the switching device 14. The switching control device 14 opens and closes the circuit at a constant cycle in the simplest case, but may be provided with a simple sequencer or CPU to sequentially connect and open a plurality of light emitting diodes 11a. Here, the light emitting surface H of each light emitting diode 11a is not in contact with the upper surface of the substrate 1, and the efficiency is improved as the distance between the light emitting surface H and the upper surface of the upper substrate 1 is as narrow as possible. This is because the light is attenuated by the square of the distance, and the distance between the light emitting surface H and the upper surface of the substrate 1 is 10 mm or less, preferably 1 to 7 mm. Since the light emitting diode used here is much smaller than the ultraviolet energy generated by the irradiation lamp, a light emitting diode having a wavelength of 280 nm or more and 600 nm or less is effective for semi-curing the adhesive. This is preferable.
[0061]
The apparatus further includes a rotation driving device 16 such as a motor that rotates the substrate cradle 3 through the rotation shaft 15 and a rotation control device 17 that controls the rotation driving device 16. This embodiment is also characterized in that the substrate cradle 3 is alternately rotated at a high speed and a low speed as shown in FIG. All high-speed rotations are 1,000 to 10,000 rpm. p. m. The number of rotations is about v1, and the adhesive is spread outward in the high-speed rotation time T1, and the adhesive layer is temporarily interrupted in the low-speed rotation time T2 so that the adhesive is semi-cured. And the spread adhesive layer is not further spread by subsequent high speed rotation.
[0062]
The rotation speed v2 of each low-speed rotation time T2 is a rotation speed at which the spreading of the adhesive is not substantially performed. As a specific example, 200 to 500 r. p. m. It is. In this embodiment, each low-speed rotation period T2 is longer than each high-speed rotation time T1 because the ultraviolet energy emitted from the semiconductor light-emitting lamp 11 is weak and it takes time to semi-cure the adhesive layer. In this embodiment, a substrate having a radius of 60 mm is irradiated with ultraviolet rays in a width of several mm at positions on the circumference corresponding to 20 mm, 30 mm, and 45 mm.
[0063]
The rotation speed, the lengths of the times T1 and T2, and the like can be adjusted by the rotation control device 17. The rotation control device 17 includes a number of rotation models (high-speed rotation speed v1, low-speed rotation speed v2, and the like, which are adapted to characteristics including the viscosity of the adhesive, ambient environmental conditions, and the like based on various experiments performed in advance. (Combinations such as the length of each time) are stored, and the rotation model that meets various conditions is automatically selected by the operator selecting the rotation model or entering the data such as the adhesive properties. Selected. Note that the high-speed rotation speed and the low-speed rotation speed at each position do not have to be the same, and may be performed at a suitable rotation speed.
[0064]
Next, the operation of this embodiment will be described. First, the operator inputs necessary data such as the viscosity of the adhesive into a CPU (not shown) of the rotation control device 17. The input data varies depending on the required film thickness accuracy. By this operation, a suitable rotation model is selected in the rotation control device 17. Along with this, the rotation control device 17 sends a control signal to the rotation drive device 16, and the rotation of the rotation drive device 16 causes the substrate cradle 2 to perform the first high-speed rotation in accordance with the selected rotation model. The adhesive 1C is spread on the peripheral side. The high-speed rotation time T1 is such a length that the thickness of the adhesive layer in the substrate surface area facing the light-emitting diodes 11a arranged in an annular shape on the innermost side of the semiconductor light-emitting lamp 11 becomes a predetermined thickness.
[0065]
Then, immediately after the period T1, the switching control device 14 operates at the same time as the first low-speed rotation or at the high-speed rotation, and causes the light-emitting diodes 11a arranged in an annular shape on the innermost side of the semiconductor light-emitting lamp 11 to emit light. . Actually, the rotation control device 17 sends the signal S to the switching control device 14 immediately after sending the high-speed rotation drive signal to the rotation drive device 16 or with a delay of time T1 to operate it. The ultraviolet light from the semiconductor light-emitting lamp 11 causes the adhesive layer having a substantially predetermined thickness in the substrate surface area facing the light-emitting diode 11a to be in a semi-cured state, and does not move outward in the radial direction due to centrifugal force due to high-speed rotation thereafter.
[0066]
Next, the second high speed rotation is performed, and the adhesive is spread again to a predetermined thickness within a certain range. The range corresponds to a substrate surface area facing the light emitting diode 11a arranged second inside the semiconductor light emitting lamp 11 that emits light for the second time, and the adhesive layer in the substrate surface area is semi-cured. By repeating such an operation for the third time, the adhesive layer of the annular surface area having a width from the inner periphery toward the outer periphery is spread to a predetermined thickness and semi-cured, and the predetermined thickness is determined. Thus, an adhesive layer having a uniform thickness as a whole is formed so as not to be affected by centrifugal force due to subsequent high-speed rotation.
[0067]
In addition, after the semiconductor light-emitting lamp 11 positioned on the inner peripheral side once emits light, it is preferable that the light emission is preferably performed in a surface that promotes curing until the bonding process of one substrate is completed.
[0068]
Although not shown, as a similar embodiment, by using a laser diode that generates ultraviolet rays having a wavelength range of 280 nm or more and 600 nm or less instead of the light emitting diode, the cost increases, but the low-speed rotation time can be shortened. The time required for the optical disc bonding process can be shortened. In this case, one piece may be arranged on each circumference, or several pieces may be arranged at equal intervals.
[0069]
With reference to FIG. 9, another embodiment using the light irradiation member 18 to which the plasma display technology or the like is applied instead of the semiconductor light emitting lamp of the above embodiment will be described. The same symbols as those used in the above-described embodiments indicate corresponding members.
[0070]
As is well known, a plasma display panel has a large number of electrodes arranged in a predetermined arrangement, and it is well known that only a portion where a voltage is applied between the electrodes emits light. This embodiment uses such a function. However, since ultraviolet rays are used in this embodiment, the filter material for cutting the ultraviolet rays is removed, and the ultraviolet rays are easily emitted to the outside. Here, a structure that easily emits ultraviolet rays to the outside is called plasma means.
[0071]
The light beam irradiating member 18 made of plasma means is preferably arranged at a distance of about 1 to 7 mm from the substrate 1, and the irradiation pattern control device 19 sequentially shifts the irradiation from the inner circumference side to the outer circumference side as in the above embodiment. However, since the energy of ultraviolet rays emitted from all normal ones is small, it is necessary to alternately perform high-speed rotation and low-speed rotation as shown in FIG. However, since the rotation control is the same as in the above embodiment, the description is omitted.
[0072]
The irradiation pattern control device 19 has a plurality of irradiation patterns (irradiation width, each irradiation time, each irradiation pause time, etc.) adapted to characteristics including the viscosity of the adhesive, ambient environmental conditions, etc. from various experiments conducted in advance. ) Is stored, and the operator selects an irradiation pattern, or inputs data such as adhesive characteristics, so that an irradiation pattern suitable for various conditions is automatically selected. However, each irradiation time and each irradiation stop time may be set in conjunction with the high-speed rotation time T1 and the low-speed rotation time T2 in the rotation model selected by the rotation control measure 17.
[0073]
In the irradiation pattern control device 19, the rotation control device 17 gives a drive signal to the rotation drive device 16 to cause the substrate cradle 3 to perform the first high-speed rotation as shown in FIG. The control signal S is received from the rotation control device 17 with a delay of T1. With this control signal S, the irradiation pattern control device 19 causes the pixels in the circumferential region of the light irradiation member 18 located on the innermost side according to the irradiation pattern to emit light during the first low-speed rotation time T2 of the substrate cradle 3. The annular portion of the innermost adhesive is semi-cured in response to the ultraviolet rays generated by the light emission.
[0074]
Next, when the second high-speed rotation time is entered, the irradiation pattern control device 19 stops the irradiation of the light beam irradiation member 18, and when the second low-speed rotation time is reached, the second inner peripheral side of the light beam irradiation member 18 according to the irradiation pattern. A pixel (not shown) in the circumferential portion located at is illuminated. Thereafter, such an operation is repeated, and the adhesive layer is semi-cured to the outermost side of the substrate 1. Thereafter, the substrate is transferred to another position (not shown), and the adhesive layer is completely cured by irradiation with ultraviolet rays. In the process of semi-curing, it is preferable that the light-emitting portion of the light irradiation member 18 is in a light-emitting state until the end of each bonding step from the viewpoint of promoting curing. The light irradiation member 18 used in this embodiment preferably uses a structure in which annular electrodes having different radii are arranged at regular intervals as electrodes.
[0075]
As described above, in this embodiment as well, the above-described operation is repeated a plurality of times, so that the annular adhesive layer having a width from the inner periphery toward the outer periphery is spread to a predetermined thickness and semi-cured. By sequentially determining the predetermined thickness, it is possible to prevent the effect of centrifugal force due to subsequent high-speed rotation and to form an adhesive layer having a uniform thickness as a whole.
[0076]
In the above embodiment, the process of forming an adhesive layer having a uniform thickness between the substrates is described. However, the liquid substance supplied in an annular shape on the inner peripheral side on the substrate is changed from the inner peripheral side to the outer peripheral side. The present invention can be similarly applied to a case where a film having a uniform film thickness is formed by extending the entire surface. In particular, as described above, it is effective for forming a light-transmitting protective layer for a next-generation large-capacity optical disk that requires a highly accurate film thickness.
[0077]
Here, the light irradiating member 18 such as a light emitting diode or a plasma means is weak in intensity of emitted light, but generates heat, compared with a lamp that emits ultraviolet light such as a normal discharge lamp or xenon lamp. Therefore, since the thermal influence on the substrate is small, the distance between the light emitting surface H and the substrate 1 can be greatly reduced as compared with the case of the lamp. Therefore, even with light from the light irradiation member 18, the liquid material can be semi-cured in a relatively short time.
[0078]
Furthermore, instead of the mechanical shutter of the above embodiment, a liquid crystal shutter using liquid crystal technology may be used. That is, a liquid crystal shutter is provided between the irradiation lamp and the substrate, and an electric signal is given to the liquid crystal, so that light rays are sequentially added from the inner periphery to the outer periphery, and the adhesive layer between the substrates or the resin on the substrate The layer is semi-cured to a predetermined thickness. When a liquid crystal shutter is used, the operation speed can be increased.
[0079]
In the above embodiment, a film thickness sensor (not shown) is used to sequentially detect the film thickness from the inner circumference side, and the detected film thickness is compared with a predetermined set film thickness. The adhesive layer may be semi-cured or cured by irradiating ultraviolet rays. The film thickness sensor is realized by the same concept as the laser displacement meter, and the measurement principle of the laser displacement meter will be briefly described. The measurement principle is a system applying triangulation, which is configured by combining a light emitting element and a light receiving element, and a semiconductor laser is used as the light emitting element. Laser light emitted from the semiconductor laser is condensed through the light projecting lens and irradiated onto the adhesive layer through the substrate. A part of the light beam reflected from the adhesive layer forms a spot on the light receiving element through the lens. When the thickness of the adhesive layer changes, the incident angle of the reflected light incident on the light receiving element of the thickness sensor changes, so that the thickness between the substrate and the adhesive layer can be known. Since the thickness of the substrate is known in advance, the thickness of the adhesive layer can be detected momentarily by correcting the thickness of the substrate.
[0080]
The same detection is possible using a CCD. Although not shown, it is also possible to detect the film thickness from the intensity of the reflected light using a rod-shaped CCD sensor in which CCD elements are laid in a range corresponding to the length of the radius of the substrate 1.
[0081]
In the above description, for easy understanding, the transition of light irradiation at a constant speed from the inner periphery side to the outer periphery, or the repetition of a constant light irradiation time and its rest time has been described, but the change in film thickness is large. The inner peripheral portion and the outer peripheral portion having a relatively large film thickness change may be performed more finely than the intermediate portion between them.
[0082]
In the present invention, since the liquid material is spread by the spinner and is semi-cured or cured sequentially, when the substrate is transported to the next step by a transfer means (not shown), the two substrates are slightly transferred as in the prior art. Therefore, an optical disk with higher quality can be obtained.
[0083]
Furthermore, a special liquid material suitable for use in the present invention will be described. Photopolymerization is started to such an extent that the UV curable liquid material currently on the market does not start to cure in the normal handling process. The light-emitting diode, the liquid crystal means, the plasma means, etc. have a lower ultraviolet intensity than flash lamps and discharge lamps. It is preferable to increase the amount within a range that does not affect the characteristics, mechanical characteristics, and storage characteristics.
[0084]
In addition, if the photopolymerization initiator added to the liquid substance is increased and the sensitivity to ultraviolet rays is considerably increased, it becomes impossible to handle the adhesive in the conventional environment. A yellow light emitting diode or the like is used, or a wavelength selection filter that cuts a wavelength range for curing a liquid substance, for example, a wavelength of 300 to 420 μm, and a lamp may be used for illumination.
[0085]
In this way, by using the ultraviolet light emitting diode as a curing device for the liquid material sensitized to ultraviolet light, and using the red light emitting diode, the plasma means, the liquid crystal means, etc. as illumination of the place where the adhesive is handled. The power usage fee can be greatly reduced, which is very favorable from the viewpoint of the environment, and the cost can be reduced.
[0086]
In the above embodiment, when an irradiation lamp is used, a mechanical shutter is used. However, as the irradiation lamp, a lamp of a type in which ultraviolet rays spread in a circle according to the distance is used, and the irradiation lamp is directly above the central hole of the substrate. The ultraviolet irradiation can be shifted from the inner periphery side to the outer periphery of the substrate by arranging and moving the irradiation lamp gradually upward along with the spread by the high-speed rotation of the substrate. Therefore, the mechanical shutter can be omitted.
[0087]
Further, as the irradiation lamp, for example, a lamp capable of forming an ultraviolet spot having a diameter of about 10 mm on the substrate 1 is used, and the ultraviolet spot is moved from the inner peripheral side toward the outer periphery of the substrate, thereby rotating the substrate. Then, ultraviolet spots are sequentially irradiated from the inner circumference side to the outer circumference along circles having different diameters. Therefore, since the mechanical shutter can be omitted, it is advantageous in terms of cost and miniaturization, and the transfer operation of the substrate to the spinner becomes easy.
[0088]
In the embodiment shown in FIG. 5, the mechanical shutter is cooled by cooling air from the horizontal direction in the drawing. However, there is a cooling mechanism for the irradiation lamp that allows cooling air to flow from above the lamp. Of course, the mechanical shutter may be cooled using wind. In this case, it is not necessary to separately provide a mechanical shutter cooling mechanism. However, if the wind blown from the upper side through the irradiation port of the mechanical shutter to the substrate 1 causes inconvenience, a heat resistant glass is provided between the spinner and the mechanical shutter. Should be provided.
[0089]
When a light emitting diode, a plasma display panel, or the like is used as the light irradiation means, the power usage fee can be greatly reduced, which is very preferable from the viewpoint of the environment, and the cost can be reduced.
[0090]
【The invention's effect】
  According to the present invention, the liquid material is spread during high-speed rotation, and light is irradiated when the liquid material is not substantially spread, so that the portions having a predetermined thickness are sequentially cured or semi-cured. Since the thickness is determined, the film thickness can be made more uniform, and a light emitting means with low light emission energy can be used, and the thermal influence on the substrate can be reduced.
[Brief description of the drawings]
FIG. 1 shows a diagram in which two substrates of an optical disk are superposed via an adhesive.
FIG. 2 is a diagram for explaining one embodiment of a resin film forming method and apparatus according to the present invention.
FIG. 3 is a view for explaining an embodiment of a resin film forming method and apparatus according to the present invention.
FIG. 4 is a diagram showing an example of a mechanical shutter used in the present invention.
FIG. 5 is a view for explaining another embodiment of the resin film forming method and apparatus according to the present invention.
FIG. 6 is a view for explaining another embodiment of the resin film forming method and apparatus according to the present invention.
FIG. 7 is a view for explaining an example of a semiconductor light emitting lamp used in the resin film forming method and apparatus according to the present invention.
FIG. 8 is a view for explaining an example of a rotation model of the resin film forming method and apparatus according to the present invention.
FIG. 9 is a view for explaining another embodiment of the method and apparatus for forming a resin film according to the present invention.
FIG. 10 is a diagram showing the relationship between the distance in the radial direction of the substrate and the film thickness of the resin film.
[Explanation of symbols]
1 ... Board
2 ... Spinner
3 ... Substrate cradle
4 ... Coater house
5 ... Mechanical shutter
6 ... Irradiation lamp
7 ... Shutter drive device
8 ... Shutter control device
9. Wavelength selection filter
10 ... heat resistant glass
11 ... Semiconductor light emitting lamp
12 ... Power supply
13 ... Protective resistance
14 ... Switch control device
15 ... Rotating shaft rod
16 ... Rotation drive device
17 ... Rotation control device
18: Light irradiation member
19 ... Irradiation pattern adjustment device

Claims (14)

  The step of spreading the liquid material supplied in an annular shape to the center side of the substrate by high-speed rotation and the step of rotating at low speed are alternately performed a plurality of times. A method of forming a resin film, wherein the liquid substance is sequentially semi-cured or cured from the inner peripheral side by shifting the irradiation. In claim 1 ,
A method for forming a resin film, characterized in that a resin film having a substantially uniform thickness is formed by setting each time of the low-speed rotation to a length required for semi-curing or curing the liquid substance. In claim 1 or claim 2 ,
The method of forming a resin film, wherein the low-speed rotation is performed at a rotational speed such that the liquid substance does not substantially spread by the centrifugal force, thereby forming a resin film having a substantially uniform thickness. In any one of Claims 1 thru | or 3 ,
The liquid substance is an adhesive supplied between the transparent first substrate and the second substrate, and an adhesive layer having a substantially uniform thickness is formed by irradiating the light through the substrate. Forming a resin film. In any one of Claims 1 thru | or 3 ,
The liquid material is made of a transparent synthetic resin material, and a light transmission protective layer having a substantially uniform thickness is formed on the substrate. In any one of Claims 1 thru | or 5 ,
The liquid material supplied in an annular shape is irradiated with light continuously or intermittently on a portion that has been spread by the high-speed rotation and has a predetermined thickness, so that the predetermined material is sequentially applied from the inner peripheral side. A method for forming a resin film, characterized in that the thickness is determined. In any one of Claims 1 thru | or 5 ,
Using at least the rotational speed and characteristics including the viscosity of the liquid substance as parameters, data for obtaining a predetermined thickness of the liquid substance supplied in the annular shape is obtained in advance, and the irradiation of the light beam is performed based on the data. A method for forming a resin film, comprising: forming a resin film having a substantially uniform thickness by determining timing. In any one of Claims 1 thru | or 5 ,
In the process in which the liquid material supplied in an annular shape is spread by the high speed rotation, the thickness of the liquid material to be spread is detected, and when the film thickness becomes a set thickness, the set thickness A method for forming a resin film, comprising forming a resin film having a substantially uniform thickness by irradiating the portion with the light beam. In any one of Claims 1 thru | or 8 ,
A method for forming a resin film, comprising: forming a resin film having a substantially uniform thickness by irradiating light onto the entire surface of the resin film after the resin film is formed from the liquid material. A spinner that alternately performs the operation of spreading the liquid substance supplied in an annular shape on the center side of the substrate by high-speed rotation and the operation of rotating the liquid material a plurality of times alternately ;
A light irradiation means to migrate the irradiation of sequential light toward the outer peripheral side from the center side during the low speed rotation,
And the liquid material is semi-cured or cured from the center side. In claim 10 ,
The selective light irradiating means comprises a light emitting means and a mechanical shutter in which a central hole is opened continuously or intermittently, and an irradiation surface area of light from the light emitting means is increased as the central hole is opened. An apparatus for forming a resin film, wherein a resin film having a substantially uniform thickness is formed by enlarging the substrate toward the outer peripheral side. In claim 10 ,
The selective light irradiation means is a light emitting lamp including a semiconductor light emitting element having a plurality of concentric circular arrangements, and the semiconductor light emitting element arranged on the outer peripheral side from the semiconductor light emitting element arranged on the inner peripheral side. An apparatus for forming a resin film, wherein a resin film having a substantially uniform thickness is formed by sequentially emitting light toward an element. In claim 10 ,
The selective light irradiating means is a light emitting means that is located at a position facing the central hole of the substrate and can move substantially perpendicularly to the surface of the substrate, and the substrate is rotated by the spinner to apply the adhesive. An apparatus for forming a resin film, wherein the light emitting means moves away from the substrate in the process of spreading. In claim 10 ,
The selective light irradiation means is a light emitting means for generating spot light, and the spot light is moved from the center side of the substrate to the outer peripheral side in the process of spreading the adhesive by rotating the substrate by the spinner. An apparatus for forming a resin film, wherein

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