JP2972865B2 - Tiny droplet application method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for applying a very small amount of liquid droplets, which is used in the chemical field, the microassembly, and other industrial fields that require the application of extremely small amounts of liquid droplets.

[0002]

2. Description of the Related Art Conventionally, various techniques have been proposed in the chemical field and the like for applying a small amount of reagents or applying a small amount of an adhesive for bonding a small part in a fine assembly. For example, a method is known in which a liquid material such as an adhesive is filled in a tube, that is, a hollow cavity, and the material is extruded by applying pressure from the root. This method has an advantage that it is relatively insensitive to the type of the liquid material, the working environment, and the like, as compared with a method of attaching and transferring the liquid material to the tip of a needle described later. A dispenser that can control the amount of the liquid material discharged by using this method and can easily respond to automation is a dispenser. However, since this dispenser controls the amount of application by pressure, and there is a limit to the miniaturization of the tube diameter, it is very difficult to accurately extrude a small amount of liquid material, and the liquid material that can be applied is There is a limit to the minimum amount of That is, it is necessary to sharpen the needle tip in order to realize a smaller amount of coating, but the sharper the needle tip, the greater the change in the coating amount with respect to the change in pressure. In order to control, pressure control with high accuracy is required. Incidentally, the minimum amount of the liquid material that can be applied by this dispenser is 1 mm ³ (10 ⁻⁶ l) at present. In addition, syringes and pipettes are known as this type of system using a tube, but in this case, a skilled worker is required, air bubbles and the like are likely to enter, and the tube diameter is the same as that of the dispenser. Problem.
The minimum amount that can be applied in this method is 0.1 mm ³
(10 ⁻⁷ l).

On the other hand, a method is known in which a liquid material is attached to the tip of a needle and is transferred to a coating portion. In particular, there is a report of automating this in micro-adhesion [Transactions of the Japan Society of Mechanical Engineers (C) 61]. Volume 581 (1995.1) 31
8 to 323].

[0004]

However, in the method of attaching and transferring a liquid material to the tip of the needle, the shape and size of the tip of the needle, the length of the needle to be immersed in the liquid material upon attachment, and the needle are handled. Various times related to time (immersion time in liquid, time until application, contact time during transfer, etc.), viscosity of liquid, various parameters such as temperature and humidity affecting viscosity are variously related There is a problem that the application amount is affected. In addition, the wettability between the needle and the liquid material also causes variation in the coating amount. Therefore, in this method, it is necessary to sufficiently examine the various parameters and to carry out the method under strictly set constant conditions.
In addition, this method is different from the above-described method using a dispenser, a syringe, or a pipette, and it is necessary to perform a complicated pre-experiment every time the type of the liquid material or the working environment is changed. Furthermore, the minimum amount that could be applied in this method was only 0.01 mm ³ (10 ⁻⁸ l). Therefore, the present inventors have proposed to apply a smaller amount of droplets, that is, droplets having an application amount of several femtoliters (10 ^-15 l) or less, which are hardly affected by the type of the liquid material and the working environment. We studied diligently for the purpose.

[0005]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above, and has an outer diameter of 1 to 2 mm (outer diameter of 1 mm to 2 mm).
An outer diameter of 2 to 5 μm (outer diameter of 2 μm to 5 μm)
A micropipette-shaped glass needle with an inner diameter of 1-3 μm (inner diameter of 1 μm or more and 3 μm or less) is manufactured, and a very small amount of liquid material of several femtoliters or less is utilized from the tip of the glass needle by the capillary action of glass fiber. By introducing the desired amount and applying pressure from the bottom up,
The present invention relates to a method for applying a small amount of droplets, which is applied to a desired portion.

[0006]

The present invention will be described below in detail.
First, a glass pipe containing a glass fiber having an outer diameter of 1 to 2 mm is stretched by applying heat and tension to produce a micropipette-shaped glass needle having an outer diameter of 2 to 5 μm and an inner diameter of 1 to 3 μm. This glass tube containing glass fiber having an outer diameter of 1 to 2 mm has a structure in which glass fiber of about 100 μm is contained inside the tube, and a tube already provided on the market for the field of processing living cells and cultured cells is used. be able to. In order to extend the glass tube, a part of the glass tube may be exposed to the flame heat of a burner or the like while holding the glass tube with both hands to apply tension in the left and right direction. It is desirable to use a commercially available device for manufacturing. This device has a structure in which electric heat is applied to a part of a glass tube, the glass tube is stretched by the action of a load (tension), and the glass tube is torn off, so that reproducible and uniform processing can be performed. In addition, the outer diameter of the extended glass needle is 2 to 5 μm.
The reason why the inner diameter is set to 1 to 3 μm is that the resolution that can be observed with an optical microscope is 2 μm for the outer diameter (1 μm for the inner diameter).
If it is less, it may become difficult. Secondly, when the outer diameter is less than 2 μm (inner diameter 1 μm), the liquid introduced into the glass needle cannot be discharged unless there is a pressing force of 5 kgf / cm ² or more, and there is a risk of scattering. No. In addition, since the introduction amount is controlled by the height of the liquid material introduced by capillary action, there is no problem when applying droplets on the order of microliters. In the present invention, the outer diameter is 5 μm (the inner diameter is 3 μm)
If it exceeds, the height of the liquid to be introduced will vary,
As a result, the application amount varies.

Next, the tip of the micropipette-shaped glass needle prepared as described above is inserted into a liquid material (supply base material), and a desired amount of the liquid material is introduced by utilizing the capillary phenomenon. The liquid material is not particularly limited, and may be a single component liquid, solution, dispersion or the like. Therefore, the present invention can be applied to various fields. The viscosity of the liquid material may be low enough to be introduced by capillary action, and a viscosity that adheres to the outer periphery of the glass needle is not preferable. For example, if a mark or a scale is provided on the outer periphery of the glass needle with a writing instrument or the like as appropriate, the liquid material can be adjusted to a desired amount (length of the introduced portion) while visually checking the introduction state of the liquid material with a microscope. The tip of the glass needle can be easily taken out from the (supply base material). In addition, in the case of an ordinary hollow needle containing no glass fiber, a liquid cannot be introduced when the outer diameter becomes several μm.

[0008] Subsequently, the tip of the glass needle is brought into contact with or close to the point to be applied, and by applying an appropriate pressure from the root, all the liquid material introduced into the inside of the glass needle is extruded and applied. Since a desired amount of the liquid material is introduced into the glass needle, there is no need to control the pressure, and it is sufficient to extrude and apply all of the liquid material.

In the present invention comprising the above three steps, it is hardly affected by the type of the liquid material and the working environment, and it is possible to easily apply droplets of several femtoliters or less. For example, in the method of attaching and transferring a liquid material to the tip of the needle described above, various parameters such as the viscosity of the liquid material and various times required when handling the needle, wettability, etc., have influenced the application amount. In the present invention, these parameters have almost no effect. Specifically, in the present invention, if the liquid material is introduced from the tip of the glass needle by the capillary action, the magnitude of the viscosity has no effect on the introduced amount, that is, the applied amount. Further, since wettability is not involved at all, for example, an aqueous liquid or a non-aqueous liquid can be similarly treated. Further, in the present invention, the operation of inserting the glass needle into the liquid material (supply base material) to introduce a desired amount of the liquid material can be easily controlled by visual observation with a microscope as described above, instead of time. . On the other hand, in the above-described method of attaching to the tip of the needle, the dispersion is extremely large visually (cannot be controlled), and therefore, the method is intended to be controlled by time.
In the above-described method using a dispenser, a cylinder, or a pipette, a required amount is discharged by introducing a liquid material by suction force and controlling the pressure. There was a limit to the minimum amount of body.
However, in the present invention, a small amount of liquid droplets of a few femtoliters or less can be introduced by capillary action and a small amount of liquid droplets can be easily applied without requiring advanced pressure control.

[0010]

The present invention will be described in more detail with reference to the following examples. First, a glass tube “GD-1” with a core of NARISHIGE CORPORATION having an outer diameter of 1 mm was used with an outer diameter of 2 μm (length of an extended portion 1 cm) and an inner diameter of 1 μm using a “Micropipette maker PC-10” manufactured by NARISHIGE. Stretched. The stretching was performed with a weight of 60 g. Next, as shown in FIG. 1, a minute amount of droplets was applied. In the figure, reference numeral 1 denotes a micropipette-shaped glass needle formed by applying heat and tension to a glass tube containing glass fiber, and 2 denotes a glass fiber which has been expanded. Followed by a glass tube. The tip of the glass needle 1 is inserted into a water droplet (diameter: about 1 mm to several hundred μm) 3, and a desired minute amount of water 4 is introduced by utilizing a capillary phenomenon.
The tip was exposed to a desired location and pressurized to apply a desired amount of minute droplets (water droplets) 4 '. All operations were performed through a microscope. As shown in FIG. 2A, assuming that the length of the water 4 introduced into the glass needle 1 is h and the diameter of the applied minute droplet 4 ′ is d, the relationship shown in FIG. 2B is obtained. Was done. Since the relationship is approximately proportional, it was confirmed that the present invention can easily control the amount of droplets. In addition, diameter 2
In the case of μm, the height of the droplet was 1 μm. Than this,
Since the shape of the droplet is estimated to be hemispherical, the volume of the droplet in this case is estimated to be 1.17 femtoliters (10 ^-15 l). Therefore, it was confirmed that the present invention can easily apply a small amount of droplets of several femtoliters.

An adhesive (Norland Pr.) Is used instead of water.
products "NOA 81", viscosity 23.5 cp
s), a similar experiment was performed.
Almost the same results as in (b) were obtained. Therefore, it was confirmed that since the amount of the liquid material that can be introduced into the glass needle by the capillary action is controlled by the amount of the liquid material, the type and viscosity of the liquid material are not affected at all.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and can be implemented in any manner without changing the configuration described in the claims. .

[0013]

As described above, according to the present invention, unlike the conventional various methods, it is not affected by the type of the liquid material and the working environment, and the extremely small amount of several femtoliters or less which could not be achieved in the past. It is possible to easily apply a small amount of droplets. Therefore, application to various fields is expected, for example, in the case of applying a very small amount of a reagent in the chemical field or the like, or in the case of applying a very small amount of an adhesive for bonding a small part in a fine assembly.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a step of introducing a liquid material and a step of coating a desired portion in the present invention.

FIG. 2 is a correlation diagram showing a relationship between a droplet length d and an introduction length h.

[Explanation of symbols]

 Reference Signs List 1 glass needle 2 glass fiber 3 liquid material (supply base material) 4 minute amount of liquid material introduced into glass needle 4 'applied minute amount of droplet d d diameter of applied minute amount of droplet h introduction into glass needle length

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B05D 1/00-7/26 B05B 1/00 B05C 19/04 H05K 3/22

Claims (1)

(57) [Claims] 1. A glass tube containing glass fiber having an outer diameter of 1 to 2 mm is expanded by applying heat and tension to the glass tube.
μm, a micropipette-shaped glass needle with an inner diameter of 1 to 3 μm is produced, a small amount of liquid material is introduced from the tip of the glass needle by utilizing the capillary action of glass fiber, and pressure is applied from the root, A micro-droplet coating method characterized in that it is applied to a desired location.