JPH0421553B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to, for example, a lens, a reflecting mirror, a light receiving element,
The present invention relates to a curved surface molding method used for molding various curved surfaces that require high precision, including optical curved surfaces in light emitting devices and the like.

[Prior Art] Generally, when trying to obtain a curved surface, it is extremely difficult to form the curved surface with high precision, even when the curved surface is a spherical surface, but especially when the curved surface is an aspherical surface.

Conventionally, the curved surface of an aspherical lens intended to correct lens aberrations, for example, has been formed by cutting the spherical lens with a cutter, pouring it into a mold with a desired aspherical surface, or vapor-depositing it onto the spherical lens. .

However, in this case, unevenness occurs depending on the degree of contact with the cutter, so it is necessary to re-polish after cutting, and for this reason, deviation from the set curved surface is unavoidable. In this case, not only is the accuracy of the curved surface of the mold itself a problem, but also the high temperature material (molten glass) is poured and cooled, which may cause distortion due to uneven cooling and non-uniformity of the interface in contact with the mold. ization becomes a problem. In this case, it is not only difficult to apply vapor deposition uniformly to a curved surface, but also it is necessary to perform vapor deposition while gradually shifting the coverage area of the mask according to the desired curved surface condition, making the work complicated and prone to errors. .

As described above, it is extremely difficult to mold a desired curved surface with high precision, and especially in the case of an aspherical surface, considerable errors are unavoidable.

[Problems to be Solved by the Invention] The problem to be solved by the present invention is to enable molding of curved surfaces with high precision even if they are aspherical.

[Means for solving the problems] In the present invention, the means taken to solve the above problems are as follows:
The object of the present invention is to provide a curved surface forming method in which a base material is reciprocated with respect to the liquid surface in a state where the curved surface is intersected with the molding surface of the base material to be molded.

In the present invention, the monomolecular film refers to an ultra-thin film with a uniform thickness in which one molecule is connected in a planar manner. The base material is an object on which a curved surface is to be molded, and is mainly an optical system member such as a lens, a reflecting mirror, a light receiving element, a light emitting element, etc., but other materials may also be used. Also, the state where the molding surface of the base material and the liquid level intersect is
A state in which part of the molding surface of the base material is submerged below the liquid level, and at the same time, part of the molding surface is exposed above the liquid level.

[Operation] When the base material is moved, a certain range of the molding surface of the base material moves up and down with the liquid level as a boundary, depending on the amplitude of this movement. On the other hand, as the base material moves, the monomolecular film formed on the liquid surface is deposited and accumulated in a meandering pattern on the molding surface of the base material that moves up and down with the liquid level as a boundary. The ability to transfer a monomolecular film onto a smooth surface and to accumulate it is known as the monomolecular accumulation method (Langmeur-Blodget method), and in the present invention, this method can be applied to curved surfaces. It is used for. In particular, in the present invention, by moving the base material in a state where the molding surface of the base material and the liquid level intersect, the accumulated range of adhesion of the monomolecular film can be adjusted by the amount of movement of the base material. It is. Then, by accumulating the monomolecular film while adjusting the cumulative adhesion range and cumulative number of the monomolecular film by the amount of movement and number of movements of the base material, we can create a monomolecular film with a uniform thickness of one molecule. ,
It is possible to adjust the curved surface condition in angstrom units, and it is possible to mold curved surfaces with high precision.

[Example] In FIG. 1, reference numeral 1 denotes a film forming apparatus, in which an inner frame 4 made of a material such as polypropylene to which a monomolecular film is difficult to adhere is horizontally placed inside a liquid tank 3 containing a liquid 2, and further Inside this inner frame 4, a film forming frame 5 made of a material to which a monomolecular film does not easily adhere is floated. The film forming frame 5 is a rectangular parallelepiped whose width is slightly shorter than the inner width of the inner frame 4, and is movable in the left-right direction in the figure.

A drive section 7 attached to a support section 6 is located above the liquid tank 3 on the left side in the figure. A support shaft 8 is suspended from the drive section 7, and a jig 10 for holding a base material 9 is attached to the tip of the support shaft 8.

As shown in FIG. 2, the jig 10 is screwed onto the tip of the support shaft 8 and is attached to the base material 9.
It can be converted accordingly. This jig 10 has claws 11 on all sides of the lower end, and the base material 9 is held by hooking the peripheral edge of the base material 9 onto the claws 11. The claw portion 11 of the jig 10 is
They may be provided not only on the four sides shown in FIG. 2 but also all around the circumference. Moreover, as shown in FIG.
If 1 is thin and short, it will not get in the way.
Furthermore, as shown in FIG.
3, it is possible to reduce the area that the jig 10 cuts through the liquid surface when the jig 10 is moved by the drive unit 7, which will be described later, and it is possible to suppress disturbance of the monomolecular film on the liquid separation surface 12. Therefore, it is preferable. If this pin 13 is bent outward, the position where the liquid level 12 of the jig 10 is cut is moved away from the base material 9, and the jig 1
0 is preferable because it can make it difficult for the base material 9 to be affected by the monomolecular film.

On the other hand, the drive unit 7 shown in FIG. It is made to linearly reciprocate up and down together with the jig 10 via the support shaft 8. For example, when forming a curved surface on the lower surface of the base material 9, the base material 9 is reciprocated up and down with the liquid level 12 intersecting the lower surface of the base material 9, as indicated by the symbol in FIG. 2a. Ru. In addition, when forming a curved surface on the upper surface of the base material 9, the base material 9 is reciprocated up and down with the liquid level 12 intersecting the upper surface of the base material 9, as indicated by the symbol in FIG. 2a. Ru. The movement of the base material 9 by the drive unit 7 is not limited to the vertical direction, but may be in the oblique direction.

The liquid 2 stored in the liquid tank 3 is usually pure water, and after cleaning the liquid surface 12, the film forming frame 5 is moved to the right side in Fig. 1 and dissolved in a volatile solvent such as benzene or chloroform. A few drops of the solution of the membrane constituent material prepared above are dropped onto the liquid surface 12 using a dropper or the like. As the membrane-constituting substance, a substance composed of molecules having at least a hydrophobic part and a hydrophilic part within the same chemical structure is usually used. Common hydrophobic moieties include, for example, long-chain alkyl groups having about 5 to 30 carbon atoms, and common hydrophilic moieties include, for example, polar groups such as carboxyl groups and amino groups. Specific examples of membrane constituent substances include arachidic acid and the like.

When the solution of the membrane-constituting substance is dropped onto the liquid surface and the solvent evaporates, a monomolecular film in the form of a gas film is left on the liquid surface. Next, the film forming frame 5 is moved to the left side in Figure 1, and the region of the liquid surface 12 where the monomolecular film is developed is gradually reduced to increase the surface density. As a result, the intermolecular interaction becomes stronger, and the monomolecular film passes through the state of a liquid film. It becomes a solid film. When this solid film is formed, the base material 9 is reciprocated up and down by the drive unit 7 as described above, and the monomolecular film is deposited and accumulated on the surface of the base material 9 to form a curved surface. It will be done. The optimal state of the monomolecular film to be transferred to the base material 9 can be determined by the surface pressure of the monomolecular film being 15 to 30 dyn/cm. As the monomolecular film is accumulated on the base material 9, the areal density of the monomolecular film molecules on the liquid surface 12 decreases, and the surface pressure also decreases, so the forming frame 5 is gradually moved to reduce the surface pressure. The monomolecular film is transferred to the base material 9 while being held constant. Further, the movement speed of the base material 9 is preferably 1 cm per minute or less so that the monomolecular film can be reliably deposited and accumulated without disturbing it.

Next, the accumulation process of adhesion of the monomolecular film to the base material 9 will be explained with reference to FIG.

First, when the base material 9 is moved upward (the same is true when moved downward) in a state where the molding surface of the base material 9 and the liquid level 12 intersect as shown in FIG. 5a, as shown in FIG. 5b, The monomolecular film A adheres to the surface of the base material 9 and is transferred. After moving the base material 9 upward by a predetermined amount, if the base material 9 is moved downward while maintaining the intersection between the molding surface of the base material 9 and the liquid level 12, as shown in FIG. A monomolecular film is superimposed on the monomolecular film A attached to the surface of the base material 9, and by repeatedly moving the base material 9 up and down,
As shown in d, the monomolecular film A is deposited and accumulated on the surface of the base material 9 one after another in a meandering manner.

When the base material 9 is a spherical lens, if the monomolecular film is deposited and accumulated as described above, the monomolecular film will be deposited and accumulated in the area shown by diagonal lines in FIG. The width of this donut-shaped monomolecular film accumulation area is determined by the amount of vertical movement of the base material 9, and the adhesion thickness of the monomolecular film is determined by the number of layers of the monomolecular film attached, that is, the amount of the base material 9. Determined by the number of movements. Therefore, if the monomolecular film is deposited and accumulated while adjusting the amount and number of times the base material 9 is moved by the drive unit 7 (see Fig. 1), the monomolecular film can be deposited while changing the deposited thickness within an arbitrary range. It can be deposited and accumulated, making it easy to mold a spherical lens into an aspherical lens, for example.

When the monomolecular film is accumulated on the base material 9, the liquid level 1
After forming a monomolecular film on 2, the base material 9 is
In this state, only one layer of the monomolecular film will be attached to a portion where it is not necessary to attach a monomolecular film, for example, to the central portion of the base material 9 shown in FIG. In order to prevent this, first set the base material 9 in a state where the molding surface of the base material 9 and the liquid level 12 intersect, as shown in FIG.
A monomolecular film may be formed thereon. However, since the monomolecular film is extremely thin and even if one or two layers are attached, it can be ignored as a curved surface, so there is no need to do this. Further, if the film constituent material is a substance that causes a polymerization reaction when irradiated with ultraviolet rays, for example diacetylene, etc., and after depositing and accumulating a monomolecular film on the base material 9 as described above, this is polymerized. This is preferable because the state of adhesion of the monomolecular film to the base material 9 becomes stronger and more stable.

The vertical movement of the base material 9 by the drive unit 7 in the present invention is not limited to the linear up and down reciprocating movement described above, but may also include rotation about the central axis of the base material 9, or reciprocation of the base material 9. It can be applied as a tilting motion or the like.

In the case of only the linear up and down reciprocating movement described so far, if the base material 9 is, for example, a spherical lens, the molding surface of the base material 9 will be curved even if the base material 9 is moved at a constant speed. Therefore, the moving speed at the intersection with the liquid level 12 on the surface of the base material 9 will change. Therefore, the speed at which the monomolecular film is transferred to the base material 9 changes depending on the surface position of the base material 9. On the other hand, if the base material 9 is rotated around the vertical axis at the same time as the vertical reciprocating movement, the monomolecular film will be spirally wrapped around the surface of the base material 9, and the vertical movement speed and rotation will change. By keeping the speed constant, the speed at which the monomolecular film is transferred to the base material 9 can be kept constant.
Therefore, there is an advantage that the properties of the monomolecular film accumulated on the base material 9 can be easily made uniform.

On the other hand, as shown in FIG. 7, when the base material 9 is reciprocated up and down by reciprocating the base material 9 with the surface of the base material 9 and the liquid level 12 intersecting, for example, If 9 is a spherical lens, the monomolecular film will be deposited and accumulated in the shaded area in FIG. The width in the lateral direction of the monomolecular adhesion accumulation range shown in FIG. 8 can be adjusted by the amount of tilting of the base material 9, and the adhesion thickness of the monomolecular film can be adjusted by the number of times of tilting. If a monomolecular film is deposited and accumulated by such reciprocating tilting of the base material 9, a rotationally asymmetric aspherical lens such as a bifocal lens can be easily obtained by this molding. Furthermore, in addition to this tilting, if the above-mentioned linear up-and-down reciprocating movement or rotation is applied continuously or intermittently, the accumulated state of adhesion of the monomolecular film can be adjusted more delicately. Further, when the base material 9 is a lens, the center of tilting of the base material 9 is usually set on the optical axis of the lens, but asymmetric molding can also be performed by setting the center of tilting off the optical axis.

FIG. 9 is a diagram showing another embodiment, in which a support shaft 8 connected to the drive unit 7 extends below the liquid level 12, and the tip of the support shaft 8 below the liquid level 12 , the jig 10 is attached facing upward. As shown in FIG. 10, this jig 10 holds the base material 9 by placing the base material 9 on the claw portions 11 thereof. This embodiment is the same as the previous embodiment except that the base material 9 is moved from below the liquid level 12, and the same effects can be obtained.

FIGS. 11 and 12 also show other embodiments, in which molding can be carried out while monitoring the state of the molded curved surface. That is, the parallel light emitted from the collimated light source 14 travels in the direction indicated by the arrow in the figure, first changes its direction with the mirror 15a, and then is divided into reference light and measurement light with the half mirror 16. The reference light is reflected by the mirror 15b again to the half mirror 16, further reflected by the half mirror 16, and sent to the interference fringe reading device 17. On the other hand, the measurement light is sent to the mirror 15c,
It is reflected there and passes through the reference lens 18 to the jig 1.
0 to the surface of the base material 9. The measurement light reflected on the surface of the base material 9 is sent to the interference fringe reader through the reference lens 18 and the mirror 15c again, and the surface state of the base material 9 is detected from the interference state with the reference light. Therefore, while detecting the surface condition of the base material 9, it is possible to move the base material 9 according to the detection result and deposit and accumulate the monomolecular film, making the work accurate and efficient. . Note that the support shaft 8 in this embodiment is configured to be moved up and down along the support section 6 by a drive section (not shown).

In the above description, the reference light is formed by the half mirror 16 and the mirror 15b, but the reflected light from the reference lens 18 may also be used as the reference light. In addition, the surface condition of the base material 9 is detected when the surface of the base material 9 to be detected is above the liquid level 12, but this measurement position is set in advance and the surface condition is detected as the base material 9 moves. It is also possible to automatically measure when the base material 9 is moved to the position. Further, from this measurement result, the movement of the base material 9 can be controlled by a computer or the like.

[Effects of the Invention] According to the present invention, a curved surface can be formed by accumulating an ultra-thin film on the order of angstroms called a monomolecular film, and the adhesion range and cumulative number of layers of this monomolecular film can be freely adjusted. It is possible to form curved surfaces with high precision, and also to form aspherical surfaces with high precision.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of an embodiment of the present invention, Fig. 2 is an enlarged view of the jig, a is a vertical sectional view, b is a bottom view,
Figures 3 and 4 are longitudinal cross-sectional views showing other examples of the jig, Figures 5 a to d are illustrations of the monomolecular film deposition accumulation process, and Figure 6 is the monomolecular film deposition accumulation range. Figures 7a to 7c are diagrams showing the tilting state of the base material, Figure 8 is a diagram showing the cumulative adhesion range of the monomolecular film, and Figure 9 is a schematic diagram of another embodiment of the present invention. FIG. 10 is an enlarged vertical sectional view of the jig, FIG. 11 is a schematic diagram of still another embodiment of the present invention, and FIG. 12 is an enlarged view of the vicinity of the base material. 1: Film forming apparatus, 2: Liquid, 3: Liquid tank, 7: Drive section, 9: Base material, 10: Jig.

Claims (1)

[Claims] 1. A method for forming a curved surface, which comprises moving the base material back and forth with respect to the liquid surface in a state where the liquid surface on which the monomolecular film is formed intersects with the molding surface of the base material on which the curved surface is to be molded.