JP4345388B2 - Microlens manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a microlens.
[0002]
[Prior art]
In recent years, optical devices having a large number of microlenses called microlenses have been provided. Examples of such an optical device include a light emitting device including a laser, an optical fiber optical interconnection, and a solid-state imaging device having a condensing lens for collecting incident light.
[0003]
By the way, the microlens constituting such an optical apparatus has been conventionally molded by a molding method using a mold or a photolithography method.
In recent years, a proposal has been made to form a microlens having a fine pattern by using a droplet discharge method used in a printer or the like (see, for example, Patent Document 1).
[0004]
[Patent Document 1]
JP 11-142608 A (page 2-3, FIG. 1)
[0005]
[Problems to be solved by the invention]
As described above, in the conventional microlens manufacturing method using the droplet discharge method, one microlens is formed by discharging a plurality of droplets of the same amount. However, when the microlens to be formed is large, there is a problem that the shape of the microlens is destroyed due to the impact of the droplet landing.
[0006]
In addition, when the amount of ejected droplets was reduced, the impact of the droplets landing could be reduced, and a larger microlens could be formed. However, if the amount of droplets is reduced, the number of ejections required to form the microlens increases, and the time required to form the microlens increases, resulting in a reduction in efficiency.
[0007]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a microlens manufacturing method that can efficiently manufacture a microlens having a large desired shape.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a microlens manufacturing method of the present invention is a microlens manufacturing method in which a microlens is formed by discharging a plurality of droplets, which are lens materials, from a droplet discharge head onto a substrate. The volume of droplets ejected from the droplet ejection head is controlled in accordance with the amount of lens material ejected onto the substrate.
[0009]
That is, in the microlens manufacturing method of the present invention, the volume of the ejected droplet is controlled according to the amount of the lens material ejected on the substrate. Therefore, it is possible to control the impact when the droplets land on the lens material. As a result, it is possible to place more lens material on the substrate as compared with the conventional one while preventing the shape of the lens material from collapsing. That is, a large desired-shaped microlens can be manufactured.
Further, the volume of the lens material discharged from the droplet discharge head can be increased to such an extent that the shape of the lens material does not collapse. Therefore, it is possible to reduce the number of times droplets are ejected before the microlens is completed, and it is possible to shorten the time required to manufacture the microlens.
[0010]
In order to realize the above-described configuration, it is desirable to control the volume of droplets ejected from the droplet ejection head so as to decrease in accordance with an increase in the amount of lens material ejected onto the substrate.
According to this configuration, when the amount of the lens material ejected on the substrate increases, the volume of the ejected droplet decreases. Then, the impact when the droplets land on the lens material is reduced, the shape of the lens material is less likely to collapse, and more lens material is placed on the substrate than in the conventional case where the volume of the droplet does not change. Can do.
Conversely, in the initial stage of microlens formation (the amount of lens material ejected onto the substrate is small), the volume of droplets ejected from the droplet ejection head is the same as the size of microlenses formed by conventional methods. It can be made larger than the volume of the droplets at the time. Therefore, it is possible to reduce the number of times droplets are ejected before the microlens is completed.
In addition, how to reduce the volume or mass of a droplet can be reduced in steps.
[0011]
In order to realize the above configuration, it is desirable to control the volume or mass of the ejected droplets by driving and controlling the droplet ejection head.
According to this configuration, since the volume of the ejected droplet is controlled by controlling the droplet ejection head, the volume of the droplet can be reliably controlled.
In addition, when changing the quantity of a droplet, it can control so that the quantity of the droplet may reduce 10% or more by volume. This is because by reducing the volume of the droplets by 10% or more, the shape of the lens material is less likely to collapse and a large microlens can be manufactured.
[0012]
In order to realize the above-described configuration, more specifically, drive control of the droplet discharge head may be performed by controlling a drive waveform for driving the droplet discharge head.
According to this configuration, since the volume of the droplet is controlled by controlling the driving waveform, the volume of the droplet can be controlled more reliably.
[0013]
In order to realize the above configuration, more specifically, the drive control of the droplet discharge head may be performed by controlling the drive voltage for driving the droplet discharge head.
According to this configuration, since the volume of the droplet is controlled by controlling the driving voltage, the volume of the droplet can be controlled more reliably.
[0014]
The microlens of the present invention is manufactured by the method for manufacturing a microlens of the present invention.
According to this microlens, since the volume of droplets ejected from the droplet ejection head is reduced in accordance with the amount of lens material disposed on the substrate, the microlens can be made large. .
[0015]
An optical device according to the present invention includes a surface-emitting laser and a microlens obtained by the method for manufacturing a microlens according to the present invention, and the microlens is disposed on the emission side of the surface-emitting laser.
According to this optical device, as described above, since the microlens having a higher production efficiency and a larger shape is arranged on the emission side of the surface-emitting laser, the microlens is used to remove the light-emitting laser from the light-emitting laser. It becomes possible to make the emitted light of the light parallel, etc., and thus have good light emission characteristics (optical characteristics).
[0016]
An optical transmission device according to the present invention includes the optical device according to the present invention, a light receiving element, and an optical transmission unit that transmits light emitted from the optical device to the light receiving element.
According to this optical transmission apparatus, as described above, since the optical apparatus having a good light emission characteristic (optical characteristic) is provided, the optical transmission apparatus has a good transmission characteristic.
[0017]
A laser printer head according to the present invention includes the above-described optical device according to the present invention.
According to this laser printer head, as described above, since the optical device having good light emission characteristics (optical characteristics) is provided, the laser printer head has good drawing characteristics.
[0018]
A laser printer according to the present invention includes the laser printer head according to the present invention.
According to this laser printer, as described above, since the laser printer head having good drawing characteristics is provided, the laser printer itself has excellent drawing characteristics.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
First, the manufacturing method of the microlens of this invention is demonstrated. The method for producing a microlens of the present invention includes a step of performing a liquid repellent treatment on the upper surface of a substrate, and discharging a plurality of dots (droplets) of a lens material onto the upper surface of the substrate subjected to the liquid repellent treatment by a droplet discharge method. Forming a microlens thereon.
[0020]
Here, in the present invention, the “base” means one having a surface on which a base member can be formed. Specifically, a glass substrate or a semiconductor substrate, and further various functional thin films and functional elements are formed on them. Say things. Further, the surface on which the base member can be formed may be a flat surface or a curved surface, and the shape of the substrate itself is not particularly limited, and various shapes can be employed.
[0021]
1 (a) to 1 (e) are manufacturing process diagrams of the microlens of the present invention.
In the present invention, as shown in FIG. 1A, for example, a GaAs substrate 1 is used, and a substrate 3 on which a number of surface emitting lasers 2 are formed is prepared. Then, a base member forming material is provided on the upper surface side of the substrate 3, that is, the surface on the emission side of the surface emitting laser 2, thereby forming the base member material layer 4. In the surface emitting laser 2, an insulating layer (not shown) made of polyimide resin or the like is formed around the emission port. Here, as a material for forming the base member, a light-transmitting material, that is, a material that hardly absorbs in the wavelength range of the emitted light from the surface-emitting laser 2 and therefore substantially transmits the emitted light. For example, a polyimide resin, an acrylic resin, an epoxy resin, a fluorine resin, or the like is preferably used, and a polyimide resin is particularly preferably used.
[0022]
In this embodiment, a polyimide resin is used as the base member forming material. And this polyimide resin precursor is apply | coated on the base | substrate 3, and it is set as the base member material layer 4 as shown to Fig.1 (a) by heat-processing at about 150 degreeC after that. In addition, about this base member material layer 4, hardening is not fully advanced at this stage, but it is made the hardness which can hold | maintain the shape.
[0023]
When the base member material layer 4 made of polyimide resin is thus formed, a resist layer 5 is formed on the base member material layer 4 as shown in FIG. Then, the mask 6 on which a predetermined pattern is formed is exposed using the resist layer 5 and further developed to form a resist pattern 5a as shown in FIG.
[0024]
Next, using the resist pattern 5a as a mask, the base member material layer 4 is patterned by, for example, wet etching using an alkaline solution. Thereby, the base member pattern 4a is formed on the base 3 as shown in FIG. Here, with respect to the base member pattern 4a to be formed, it is preferable to form the top surface in a circular shape, an elliptical shape, or a polygonal shape in order to form a microlens on the top surface shape. It is circular. Further, the center position of the circular upper surface is formed so as to be located immediately above the emission port (not shown) of the surface emitting laser 2 formed on the substrate 3.
Thereafter, as shown in FIG. 1E, the resist pattern 5a is removed, and a heat treatment is further performed at about 350 ° C., thereby sufficiently curing the base member pattern 4a to form the base member 4b.
[0025]
Next, the upper surface of the base member 4b is subjected to a liquid repellent treatment. As the liquid repellent treatment, for example, a method of forming a self-assembled film on the surface of the substrate, a plasma treatment method, or the like can be employed.
In the self-assembled film forming method, a self-assembled film made of an organic molecular film or the like is formed on the surface of a substrate on which conductive film wiring is to be formed.
The organic molecular film for treating the substrate surface has a functional group that can bind to the substrate and a functional group that modifies the surface properties of the substrate, such as a lyophilic group or a liquid-repellent group (controlling the surface energy) And a carbon straight chain or a partially branched carbon chain connecting these functional groups, and is bonded to a substrate and self-assembles to form a molecular film, for example, a monomolecular film.
[0026]
Here, the self-assembled film is composed of a binding functional group capable of reacting with constituent atoms such as an underlayer of the substrate and other linear molecules, and has extremely high orientation due to the interaction of the linear molecules. It is a film formed by orienting a compound. Since this self-assembled film is formed by orienting single molecules, the film thickness can be extremely reduced, and the film is uniform at the molecular level. That is, since the same molecule is located on the surface of the film, uniform and excellent liquid repellency and lyophilicity can be imparted to the surface of the film.
[0027]
By using, for example, fluoroalkylsilane as the compound having high orientation, each compound is oriented so that the fluoroalkyl group is located on the surface of the film, and a self-assembled film is formed. Liquid repellency is imparted.
Examples of compounds that form a self-assembled film include heptadecafluoro-1,1,2,2 tetrahydrodecyltriethoxysilane, heptadecafluoro-1,1,2,2 tetrahydrodecyltrimethoxysilane, heptadecafluoro-1 , 1,2,2 tetrahydrodecyltrichlorosilane, tridecafluoro-1,1,2,2 tetrahydrooctyltriethoxysilane, tridecafluoro-1,1,2,2 tetrahydrooctyltrimethoxysilane, tridecafluoro-1 , 1,2,2 tetrahydrooctyltrichlorosilane, trifluoropropyltrimethoxysilane, and other fluoroalkylsilanes (hereinafter referred to as “FAS”). These compounds may be used alone or in combination of two or more.
Note that by using FAS, adhesion to the substrate and good liquid repellency can be obtained.
[0028]
FAS is generally represented by the structural formula RnSiX _(4-n) . Here, n represents an integer of 1 to 3, and X is a hydrolyzable group such as a methoxy group, an ethoxy group, or a halogen atom. R is a fluoroalkyl group, and has a structure of (CF ₃ ) (CF ₂ ) x (CH ₂ ) y (where x represents an integer of 0 to 10 and y represents an integer of 0 to 4). And when a plurality of R or X are bonded to Si, each R or X may be the same or different. The hydrolyzable group represented by X forms silanol by hydrolysis, reacts with the hydroxyl group of the base of the substrate (glass, silicon), and bonds to the substrate with a siloxane bond. On the other hand, since R has a fluoro group such as (CF ₂ ) on the surface, the base surface of the substrate is modified to a surface that does not get wet (surface energy is low).
[0029]
A self-assembled film made of an organic molecular film or the like is formed on a substrate by placing the above raw material compound and the substrate in the same sealed container and leaving them at room temperature for about 2 to 3 days. Further, by holding the entire sealed container at 100 ° C., it is formed on the substrate in about 3 hours. These are formation methods from the gas phase, but a self-assembled film can also be formed from the liquid phase. For example, the self-assembled film is formed on the substrate by immersing the substrate in a solution containing the raw material compound, washing, and drying.
Note that before the self-assembled film is formed, it is desirable to pre-treat the substrate surface by irradiating the substrate surface with ultraviolet light or washing with a solvent.
[0030]
On the other hand, as the plasma method, for example, a plasma processing method (CF ₄ plasma processing method) using tetrafluoromethane as a processing gas in an air atmosphere is preferably employed. The conditions for this CF ₄ plasma treatment are, for example, a plasma power of 50 to 1000 kW, a gas flow rate of tetrafluoromethane (CF ₄ ) of 50 to 100 ml / min, and a conveying speed of the substrate 3 to the plasma discharge electrode of 0.5 to 1020 mm / min. sec, the substrate temperature is set to 70 to 90 ° C. The processing gas is not limited to tetrafluoromethane (CF ₄ ), and other fluorocarbon gases can be used. By performing such a liquid repellency treatment, a fluorine group is introduced into the resin constituting the upper surface of the base member 4b, thereby imparting high liquid repellency.
[0031]
Here, with respect to such a liquid repellent treatment, in particular, when a lens material to be described later is disposed on a plane formed of the material for forming the base member 4b, the contact angle of the lens material is 20 ° or more. It is preferable to perform so as to exhibit excellent liquid repellency.
That is, as shown in FIG. 6, the base member material layer 4 is formed of the base member 4b forming material (polyimide resin in this example), and the surface thereof is flat. Then, the above-described liquid repellent treatment is performed on this surface. Next, the lens material 7 is disposed on the surface by a droplet discharge method.
[0032]
Then, the lens material 7 becomes a droplet having a shape corresponding to the wettability with respect to the surface of the base member material layer 4. At this time, the surface tension of the base member material layer 4 is γ _S , the surface tension of the lens material 7 is γ _L , the interfacial tension between the base member material layer 4 and the lens material 7 is γ _SL , and the base member material layer 4 Assuming that the contact angle of the lens material 7 is θ, the following equations are established between γ _S , γ _L , γ _SL , and θ.
γ _S = γ _SL + γ _L · cos θ
As will be described later, the curvature of the lens material 7 to be a microlens is limited by the contact angle θ determined by the above formula. That is, the curvature of the lens obtained after the lens material 7 is cured is one of the factors that determine the final shape of the microlens. Therefore, in the present invention, the γ _SL is increased by increasing the interfacial tension between the base member material layer 4 and the lens material 7 by liquid repellent treatment so that the shape of the obtained microlens becomes more spherical. The contact angle θ is preferably large, that is, 20 ° or more.
In this way, the liquid repellent treatment is performed on the upper surface of the base member 4b under the condition that the contact angle θ shown in FIG. 6 is 20 ° or more, so that the liquid is discharged onto the upper surface of the base member 4b as will be described later. The contact angle θ ′ of the lens material 7 to be arranged with respect to the upper surface of the base member 4b is reliably increased. Accordingly, it is possible to increase the amount of the lens material placed on the upper surface of the base member, which makes it easy to control the shape with the discharge amount (discharge dot amount).
[0033]
When the liquid repellent treatment is performed on the upper surface of the base member 4b in this way, a plurality of dots of the lens material 7 are discharged onto the base member 4b by the droplet discharge method. Here, as a droplet discharge method, a dispenser method, an inkjet method, or the like can be employed. The dispenser method is a general method for discharging droplets, and is an effective method for discharging droplets over a relatively wide area. The inkjet method is a method of ejecting droplets using a droplet ejection head, and the position of ejecting droplets can be controlled in units of μm, and the amount of ejected droplets is also in the picoliter order. Therefore, it is suitable for manufacturing a fine lens (microlens).
[0034]
2A and 2B are schematic configuration diagrams of a droplet discharge head.
Therefore, in this embodiment, an inkjet method is used as a droplet discharge method. This ink jet method includes a stainless steel nozzle plate 12 and a vibration plate 13 as a droplet discharge head 34 as shown in FIG. 2A, for example, and these are joined via a partition member (reservoir plate) 14. Use things. A plurality of cavities 15 and reservoirs 16 are formed between the nozzle plate 12 and the diaphragm 13 by the partition member 14, and the cavities 15 and the reservoirs 16 communicate with each other via a flow path 17. Yes.
[0035]
Each cavity 15 and the inside of the reservoir 16 are filled with a liquid material (lens material) for discharging, and a channel 17 between them is a supply port for supplying the liquid material from the reservoir 16 to the cavity 15. It is supposed to function as. In addition, a plurality of hole-shaped nozzles 18 for injecting a liquid material from the cavity 15 are formed in the nozzle plate 12 in a state of being aligned vertically and horizontally. On the other hand, the diaphragm 13 is formed with a hole 19 that opens into the reservoir 16, and a liquid tank (not shown) is connected to the hole 19 via a tube (not shown). It has become.
[0036]
Also, a piezoelectric element (piezo element) 20 is joined to the surface of the diaphragm 13 opposite to the surface facing the cavity 15 as shown in FIG. The piezoelectric element 20 is sandwiched between a pair of electrodes 21 and 21 and is configured to bend so as to protrude outward when energized, and functions as an ejection unit in the present invention.
[0037]
The diaphragm 13 to which the piezoelectric element 20 is bonded in such a configuration is bent together with the piezoelectric element 20 at the same time, thereby increasing the volume of the cavity 15. Then, the cavity 15 and the reservoir 16 communicate with each other, and when the reservoir 16 is filled with the liquid material, the liquid material corresponding to the increased volume in the cavity 15 flows from the reservoir 16. It flows in through the path 17.
When the energization to the piezoelectric element 20 is released from such a state, both the piezoelectric element 20 and the diaphragm 13 return to their original shapes. Accordingly, since the cavity 15 also returns to its original volume, the pressure of the liquid material inside the cavity 15 rises, and the liquid droplet 22 is discharged from the nozzle 18.
[0038]
The discharge means of the droplet discharge head may be other than the electromechanical transducer using the piezoelectric element (piezo element) 20, for example, a method using an electrothermal transducer as an energy generating element, or charging control. It is also possible to adopt a continuous method such as a mold or a pressure vibration type, an electrostatic suction method, or a method in which an electromagnetic wave such as a laser is irradiated to generate heat and a liquid material is discharged by the action of this heat generation.
[0039]
Further, as the lens material 7 to be discharged, that is, the lens material 7 that becomes a microlens, a light transmissive resin is used. Specifically, acrylic resins such as polymethyl methacrylate, polyhydroxyethyl methacrylate, polycyclohexyl methacrylate, allyl resins such as polydiethylene glycol bisallyl carbonate, polycarbonate, methacrylic resin, polyurethane resin, polyester resin, polyvinyl chloride Thermoplastic or thermosetting resins such as resin, polyvinyl acetate resin, cellulose resin, polyamide resin, fluorine resin, polypropylene resin, polystyrene resin, etc., one of which is used. Or a mixture of a plurality of species.
[0040]
The surface tension of the light transmissive resin used as the lens material 7 is preferably in the range of 0.02 N / m or more and 0.07 N / m or less. When the ink is ejected by the droplet ejection method, if the surface tension is less than 0.02 N / m, the wettability of the ink to the nozzle surface increases, and thus flight bending tends to occur. If the surface tension exceeds 0.07 N / m, the shape of the meniscus at the nozzle tip is not stable, and it becomes difficult to control the discharge amount and the discharge timing. In order to adjust the surface tension, the dispersion of the light transmissive resin does not significantly reduce the contact angle with the substrate, and does not affect the optical properties such as the refractive index. A small amount of a non-ionic surface tension regulator may be added. The nonionic surface tension modifier improves the wettability of the ink to the substrate, improves the leveling property of the film, and helps prevent the occurrence of fine irregularities on the film. The surface tension modifier may contain an organic compound such as alcohol, ether, ester, or ketone, if necessary.
[0041]
Furthermore, the viscosity of the light-transmitting resin used as the lens material 7 is preferably 1 mPa · s or more and 200 mPa · s or less. When ink is ejected as droplets using the droplet ejection method, if the viscosity is less than 1 mPa · s, the nozzle periphery is likely to be contaminated by the outflow of ink. In addition, when the viscosity is higher than 50 mPa · s, it is possible to discharge by providing an ink heating mechanism in the head or the droplet discharge device. Discharging becomes difficult. In the case of 200 mPa · s or more, it is difficult to lower the viscosity to such an extent that droplets can be discharged even when heated.
[0042]
In the present invention, a non-solvent resin is particularly preferably used as the light transmissive resin. This non-solvent light-transmitting resin dissolves the light-transmitting resin using an organic solvent and does not form a liquid material. For example, the light-transmitting resin is liquefied by diluting the light-transmitting resin with its monomer, and drops This enables ejection from the ejection head 34. In addition, the non-solvent light-transmitting resin can be used as a radiation irradiation curable type by blending a photopolymerization initiator such as a biimidazole compound. That is, by blending such a photopolymerization initiator, radiation curable properties can be imparted to the light transmissive resin. Here, the radiation is a general term for visible light, ultraviolet light, far ultraviolet light, X-rays, electron beams, and the like, and particularly ultraviolet light is generally used.
The light transmissive resin is not limited to a non-solvent type, and a solvent type light transmissive resin can also be used.
[0043]
3A and 3B are manufacturing process diagrams of the microlens of the present invention.
As shown in FIG. 3A, the lens material 7 is formed with a plurality of dots on the base member 4b and the microlens precursor 8 on the base member 4b by the droplet discharge head 34 having the above-described configuration. At this time, the base member 4 b reciprocates (scans) under the droplet discharge head 34, and each time the base member 4 b passes under the droplet discharge head 34, the lens material 7 becomes 1 from the droplet discharge head 34. Dots are ejected.
If the pitch of the nozzles 18 of the droplet discharge head 34 matches the pitch of the base member 4b, a plurality of microlenses are simultaneously formed within a range in which the positional relationship between the nozzles 18 and the base member 4b matches. Also good.
[0044]
Here, since the lens material 7 is ejected by the ink jet method, the lens material 7 can be accurately arranged at the substantially central portion on the base member 4b. Further, as described above, the upper surface of the base member 4b is subjected to the liquid repellent treatment, so that the discharged droplets of the lens material 7 are difficult to spread on the upper surface of the base member 4b. The lens material 7 arranged on the base member 4b is held in a stable state on the base member 4b without spilling from the base member 4b.
[0045]
Next, a case where the lens material 7 overflows from the base member 4b with 20 dots (200 pl in total) when all the dots are ejected with the same dot amount (10 pl) will be described by adapting the ejection method of the present embodiment.
When the lens material 7 starts to be ejected onto the base member 4b, a driving voltage having a driving waveform for ejecting a droplet having a volume of 10 pl, which will be described later, is applied to the droplet ejection head 34, and the lens material 7 having a volume of 10 pl is produced. Discharged. When 10 dots of lens material 7 having a volume of 10 pl are ejected, a driving voltage for ejecting droplets having a volume of 4 pl described later is applied to the droplet ejection head 34, and 35 dots of lens material 7 having a volume of 4 pl are ejected. At this time, a total of 240 pl of the lens material 7 is disposed on the base member 4b in a substantially spherical shape.
In addition, the amount of dots of the lens material 7 to be ejected is not limited to the above-described pattern that decreases from 10 pl to 4 pl, and can be applied to various reduction patterns. In particular, a pattern for reducing the volume of the dot amount by 10% or more is suitable for use in forming a microlens because the shape of the lens material 4b disposed on the base member 4b is difficult to break.
[0046]
4A and 4B are diagrams showing driving waveforms of the droplet discharge head 34. FIG.
When 10 pl of the lens material 7 is ejected from the droplet ejection head 34, the drive waveform shown in FIG.
A voltage of 16.1 V is applied to the piezoelectric element 20 in the first 3.5 μs, the piezoelectric element 20 is bent so as to protrude outward, and the volume of the cavity 15 increases. Thereafter, the state is maintained for 3.0 μs, and a reverse voltage of 23 V is applied so that the piezoelectric element 20 protrudes inward for the next 3.5 μs. As a result, the volume of the cavity 15 rapidly decreases, and the lens material 7 is discharged from the nozzle 18. After the state is maintained for 3.5 μs, a voltage of 6.9 V is applied for 3.5 μs to return to the initial state.
[0047]
Further, when 4 pl of the lens material 7 is ejected from the droplet ejection head 34, the drive waveform shown in FIG.
A voltage of 18.4 V is applied to the piezoelectric element 20 in the first 6.0 μs, and the rolling element 20 is bent so as to protrude outward, and the volume of the cavity 15 is increased. Thereafter, the state is maintained for 1.5 μs, and during the next 1.5 μs, a reverse voltage of 9.2 V is applied so that the piezoelectric element 20 protrudes inward, and the state is maintained for 3.0 μs. To do. Then, a reverse voltage of 13.8 V is applied so that the piezoelectric element 20 protrudes inward for 3.5 μs. As a result, the volume of the cavity 15 rapidly decreases, and the lens material 7 is discharged from the nozzle 18. After the state is maintained for 3.5 μs, a voltage of 4.6 V is applied for 3.5 μs to return to the initial state.
[0048]
The shape of the drive waveform applied to the droplet discharge head 34 and the magnitude of the voltage are not limited to the above-described ranges, and can be adapted to various ranges.
Further, the volume of the lens material 7 ejected from the droplet ejection head 34 can be controlled not only by the method for controlling the waveform of the applied voltage described above but also by the method for controlling the magnitude of the applied voltage.
[0049]
When the microlens precursor 8 having a desired size is formed in this way, the microlens precursor 8 is cured to form a microlens 8a as shown in FIG. 3B. As the curing treatment of the microlens precursor 8, as described above, since an organic solvent is not added as the lens material 7 and imparted with radiation irradiation curability, particularly ultraviolet rays (wavelength λ = 365 nm) are used. A treatment method by irradiation is preferably used.
[0050]
Moreover, it is preferable to perform the heat processing for about 1 hour, for example at 100 degreeC after the hardening process by such ultraviolet irradiation. By performing such a heat treatment, even if curing unevenness occurs at the stage of the curing process by ultraviolet irradiation, the curing unevenness can be reduced to obtain a substantially uniform curing degree as a whole.
After the microlenses 8a are formed in this way, the substrate 3 is cut as necessary, and is formed into a desired form by dividing into pieces or forming an array.
An optical device according to an embodiment of the present invention is obtained from the microlens 8a thus manufactured and the surface-emitting laser 2 previously formed on the substrate 3.
[0051]
According to said structure, the volume or mass of the droplet discharged from the droplet discharge head 34 is reduced according to the quantity of the lens material 7 discharged on the base member 4b. Therefore, for example, when the amount of the lens material 7 on the base member 4b increases, the volume or mass of the discharged droplets decreases. Then, the impact when the liquid droplets land on the lens material 7 is reduced, the shape of the lens material 7 is not easily broken, and more lens material 7 is added as compared with the conventional case where the volume or mass of the liquid droplet does not change. It can be placed on the base member 4b. That is, a large microlens can be manufactured.
[0052]
5A to 5C are diagrams showing the microlens of the present invention.
That is, the size of the microlens 8a can be increased. As shown in FIGS. 5A to 5C, when the size of the microlens 8a is increased, the focal point of the curved surface corresponding to the lens on the upper surface side is increased. The position approaches the emission surface of the surface emitting laser 2 formed on the substrate 3. When the focal position approaches the emission surface, the light emitted from the upper surface side of the microlens 8a can be made more parallel light.
On the other hand, when the light from the light emitting source such as the surface emitting laser 2 does not have a radiation property but has a straight traveling property, the transmitted light can have a radiation property by transmitting through the microlens 8a.
[0053]
Conversely, in the initial stage of microlens formation, the volume or mass of the droplets ejected from the droplet ejection head 34 is larger than the volume or mass of the droplets when the same size microlens is formed by a conventional method. Can be bigger. Therefore, it is possible to reduce the number of times droplets are ejected before the microlens is completed, and it is possible to shorten the time required to manufacture the microlens.
[0054]
Further, in the optical device comprising the thus produced microlens 8a and the surface emitting laser 2 formed on the substrate 3, the microlens 8a whose size and shape are well controlled as described above is provided. Since it is disposed on the emission side of the surface-emitting laser 2, the microlenses 8a can satisfactorily collimate the emitted light from the surface-emitting laser 2, and therefore have good emission characteristics (optical characteristics). It will have.
[0055]
In the above embodiment, the base member material layer 4 is formed on the base 3 and the base member 4b is formed from the base member material layer 4. However, the present invention is not limited to this, for example, In the case where the surface layer portion of the base body 3 is formed of a translucent material, the base member may be directly formed on the surface layer portion.
Further, the formation method of the base member 4b is not limited to the photolithography method described above, and other formation methods such as a selective growth method and a transfer method can be employed.
Also, the top surface shape of the base member 4b can be various shapes such as a triangle and a quadrangle according to the characteristics required for the microlens to be formed, and the shape of the base member 4b itself is also tapered. Various shapes such as a mold and a reverse taper type are possible.
In the above embodiment, the microlens 8a is used and functions as a lens while being formed on the base member 4b. However, the present invention is not limited to this, and the base member 4b is used. Therefore, the microlens 8a may be used as a single optical component by separating or peeling off by an appropriate method. In that case, the base member 4b used for manufacturing does not necessarily need to have translucency.
[0056]
In the present invention, in addition to the optical device comprising the surface emitting laser 2 and the microlens 8a, an optical transmission means comprising an optical fiber, an optical waveguide or the like for transmitting light emitted from the optical device, By providing a light receiving element that receives the light transmitted by the light transmission means, it can function as an optical transmission device.
Since such an optical transmission device includes an optical device having good light emission characteristics (optical characteristics) as described above, this optical transmission device also has good transmission characteristics.
[0057]
FIG. 7 is a schematic configuration diagram of a head for a laser printer according to the present invention.
The laser printer head of the present invention comprises the optical device. That is, the optical device used in the head for the laser printer includes a surface emitting laser array 2a in which a large number of surface emitting lasers 2 are linearly arranged as shown in FIG. 7, and the surface emitting laser array 2a. And a microlens 8 a disposed for each surface emitting laser 2. The surface emitting laser 2 is provided with a driving element (not shown) such as a TFT, and the laser printer head is provided with a temperature compensation circuit (not shown).
Furthermore, the laser printer of the present invention is configured by including the laser printer head having such a configuration.
[0058]
Since such a laser printer head includes an optical device having good light emission characteristics (optical characteristics) as described above, the laser printer head has good drawing characteristics.
Further, even a laser printer equipped with this laser printer head has a laser printer head with good drawing characteristics as described above, so that the laser printer itself has excellent drawing characteristics.
[0059]
The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the microlens of the present invention can be applied to various optical devices other than the above-described uses, and for example, as an optical component provided on a light receiving surface of a solid-state imaging device (CCD) or an optical coupling portion of an optical fiber. It can be used.
[Brief description of the drawings]
FIGS. 1A to 1E are manufacturing process diagrams of a microlens of the present invention.
2A and 2B are schematic configuration diagrams of a droplet discharge head. FIG.
FIGS. 3A and 3B are manufacturing process diagrams of the microlens of the present invention. FIGS.
FIGS. 4A and 4B are diagrams showing driving waveforms of a droplet discharge head according to the present invention. FIGS.
FIGS. 5A to 5C are diagrams showing a microlens of the present invention. FIG.
FIG. 6 is a diagram for explaining a contact angle of a lens material by a liquid repellent treatment.
FIG. 7 is a schematic configuration diagram of a head for a laser printer according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 2 ... Surface emitting laser, 3 ... Base | substrate, 7 ... Lens material, 8a ... Micro lens, 34 ... Droplet discharge head

Claims (5)

A microlens manufacturing method for forming a microlens by discharging a plurality of droplets, which are lens materials, from a droplet discharge head onto a substrate,
The droplets are first ejected number of times smaller than a prescribed number of times of ejection to be that the liquid droplets overflow from the substrate when discharged in the first volume, discharging a first droplet composed of the first volume,
After the first droplet ejected first discharge number of times, a second droplet of a second volume is less volume than said first volume, from the first droplet formed on the substrate By discharging onto the first combined body, the first combined body and the second liquid droplet having a volume larger than the total discharge volume when the predetermined number of discharges of the liquid droplets are discharged in the first volume. method of manufacturing a microlens of the second coupling member, characterized in that that be formed on the substrate made of.   2. The microlens according to claim 1, wherein a volume of a droplet discharged from the droplet discharge head is controlled so as to decrease in accordance with an increase in an amount of the lens material discharged onto the substrate. Production method.   3. The method for manufacturing a microlens according to claim 1, wherein the droplet discharge head is driven to control the volume of the droplet to be discharged.   4. The method of manufacturing a microlens according to claim 3, wherein the drive control of the droplet discharge head is performed by controlling a drive waveform for driving the droplet discharge head.   4. The method for manufacturing a microlens according to claim 3, wherein the drive control of the droplet discharge head is performed by controlling a drive voltage for driving the droplet discharge head.

Images