JPS59107307A - Lens fitting method - Google Patents

Abstract

PURPOSE:To match easily optical axes of each lens by making a fluid such as air, etc. flow between a bell surface of a lens holder and the surface of a lens, and making the optical axis of the lens coincide with the center axis of the lens holder by its bell effect. CONSTITUTION:When a bell part 61 of a lens holder 6 is made to press-contact with the upper face of a lens 1, and air in a recessed part 62 is absorbed from an air suction pipe 68, the lens 1 is adsorbed to a bell type holding part 61 of the lens holder 6, and air between the lens surface and the bell surface 61 flows, therefore, the lens 1 becomes easily slidable on the bell surface 61, and by the bell effect, it moves automatically so that the optical axis of the lens 1 coincides with the center line of the bell part 61. On the other hand, air is absorbed into the recessed part 62 through a passage 63 from a hole 64 of the side face of the holder 6, negative pressure corresponding to a gap between the side face of the holder 6 and the inside surface of a lens barrel 2 is generated, and the deviation of a lens is detected by a pressure sensor 66 through an air passage 65 provided at a right angle with each air passage 63.

Description

TECHNICAL FIELD The present invention relates to a lens assembly method for assembling a plurality of lenses constituting a lens system in a lens barrel with their optical axes aligned with each other.

Prior Art Conventionally, in order to incorporate a lens system consisting of a plurality of lenses into a lens barrel, the outer diameter of the lens cores is ground, and the axis is aligned by fitting the outer diameter of the lens with the inner diameter of the lens barrel. It was common practice to machine the lens holder M'a inside the barrel into a bell shape, to receive the spherical lens surface at its edge, and to align the optical axes of each lens with each other by self-aligning using the ``Nil'' effect.

Therefore, it takes a lot of time and effort to process the number of lens cores and fit the lens to the inner diameter of the lens barrel with a minute gap.
In particular, it is extremely difficult to assemble lenses that have small diameters and require high precision into the lens barrel, such as objective lenses, collimating lenses, or endoscope lenses used in optical pickup optical systems, so this method is not suitable. It was difficult to obtain good imaging performance. Additionally, machining the lens receiving surface inside the lens barrel into a bell shape (two-way processing) also had the disadvantage of increasing processing costs.

Purpose: IJI is a system that solves the two problems of the conventional method when multiple lenses constituting a lens system are assembled into a lens barrel by aligning their optical axes with each other. No machining is required, there is no need to minimize the gap between the inner diameter of the lens barrel and the outer diameter of the lens, and the optical axis of each lens can be easily aligned and assembled into the lens barrel, especially for small-diameter lenses that require high precision. The purpose is to provide a suitable lens assembly method.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail based on embodiments shown in the drawings.

FIG. 1 is a diagram showing an example of an apparatus for implementing the method of the present invention, in which a lens 1 to be assembled into a lens barrel 2 is placed and held on a lens boulder 3, and is inserted into the lens barrel 2. Group J Jinchoreru. The lens holder 6 is a measurement point of an air micrometer, and an air passage 31 is provided at the center line, and the air passage 3 is formed in a cross shape from the center point within a plane 101 perpendicular to the axis.
8° are provided and open into recesses provided on the circumferential surface at intervals of 90° to the circumferential force 1iJj. A back pressure measuring conduit 62 extends downward from the passage 68 at a position immediately in front of the opening, and a pressure sensor 36 is disposed so as to block each opening. The upper end of the air passage provided at the center line (two) opens into an opening 30 at the center of the top surface of the lens holder 6.A bell-shaped lens holding portion 6 is provided on the top surface of the lens holder 3 concentrically with the holder 6.
9 is formed. An air supply pipe 35 is connected to the lower end of the centerline air passage 61.

Adhesive discharge ports 66 are provided at a suitable number of locations on the outside of the bell-shaped lens holder M39 on the top surface of the lens holder B, and the adhesive is supplied from the adhesive tank 4 via the supply pipe 37 into the adhesive tank 4 by force. It is now possible to dispense the agent.

The outer diameter of the lens holder O is made slightly smaller than the inner diameter of the lens barrel, so that it can be inserted gently. A seating surface 21 for receiving the upper curved surface of the lens is formed on the inner surface of the lens barrel 2, and a hole 22 penetrating the side wall of the lens barrel is bored just below the seating surface 21.

The method for assembling lenses using this device will be explained below.

The lens 1 is placed on the bell-shaped lens holding portion 39 of the lens holder 3, and is inserted into the lens barrel 2 from below. Then, when air is supplied from the air supply pipe 65 to the air passage 31.58 in the lens holder 6, the air flowing out from the opening 60 on the top surface of the lens holder 3 flows between the lower spherical surface of the lens and the top surface of the lens holder 6. After increasing the pressure in the space surrounded by the bell-shaped holding part 39, it flows outward from between the edge of the bell and the lower surface of the lens 1, and a layer of air is formed between these surfaces, causing the lens 1 to The edge of the bell 39 slides easily and the optical axis of the lens 1 automatically aligns with the center m, arJ of the bell 23 and the center edge of the lens holder 3.

On the other hand, the air flowing from the air passage 61 on the center line of the lens holder O into the air passage 38 extending in a cross shape in all directions is ejected from the opening on the outer peripheral surface of the lens holder O and hits the inner surface of the lens barrel 2, causing back pressure. is detected by the pressure sensor through the air passage 62. The back pressure υj values for the four openings in the outer peripheral direction of the lens holder are determined by the control unit 5 as illustrated in FIG.
The deviation between the center line of the lens holder B and the center line of the lens barrel 2 is calculated and displayed on the cathode ray tube 51, and the lens barrel clamping device (not shown) or the lens holder 3 is automatically or manually moved between the two. Move it in the direction that eliminates the misalignment.

Thus, the center line of the lens holder B and the center line of the lens barrel 2 coincide, and the optical axis of the lens 1 also coincides with the center line of the lens holder B. As a result, the optical axis of the lens 1 is aligned with the center line of the lens barrel. Can be matched. When the center lines coincide with each other, raise the lens holder 3, bring the upper spherical surface of the lens 1 into contact with the seat surface 21 of the lens barrel, press it slightly to fix it, and discharge the adhesive into the lens holder. ”66
The adhesive is discharged by the pressure of the adhesive tank 4, and the lens 1 is fixed to the lens barrel 2. Depending on the diameter and thickness of the lens 1, the adhesive may be supplied from the hole 22 provided in the side wall of the lens barrel through the conduit 41, the syringe 42, and the injection needle 46 to fix the lens 1. Furthermore, work efficiency can be improved by increasing the adhesion speed by increasing the temperature of the air supplied from the air supply pipe 65 or by supplying a gas that accelerates the curing of the adhesive. In addition, a light-curing adhesive may be used as the adhesive, and a light guide fiber may be embedded in the lens holder 3 to guide an external light source to the bonding position to illuminate the bonded area, or depending on the configuration of the optical system, the light guide fiber may be embedded in the lens holder 3 to illuminate the bonded area, or depending on the configuration of the optical system, the light guide fiber may be embedded in the lens holder 3 and an external light source may be guided to the bonding position to illuminate the bonded area. Various bonding methods can be employed, such as irradiating IU contact light Jf (-i) to solidify the adhesive.

In the above embodiment, an air micrometer was used to measure the center deviation between the lens holder 6 and the lens barrel 2, but the measuring means is not necessarily limited to this, and may be a differential transformer type or Various known measuring means such as an electromagnetic strain type using a Hall element can be used.

In addition, when using an air micrometer, the lens holder can also be aligned by automatically moving the lens holder in a direction where the gaps between the parts are made equal based on the difference in back pressure between the openings provided at equal intervals on the circumference.

In the embodiment shown in Fig. 1, a bell-shaped lens holding part is provided on the top surface of the lens holder facing upward, and the fluid flows from the inside to the outside of the holding surface to align the optical axis of the lens with the center line of the bell. However, depending on the arrangement of the lenses, it may be more convenient to provide a bell-shaped holding portion on the lower surface of the lens holder to attract and hold the lenses.

An example of a device used in the oral case is shown in FIG.

In this case, a bell-shaped holding part 61 for holding the lens 1 is formed concentrically on the lower surface of the lens holder 6, and deep four parts 62 are formed inside the bell. Four air passages 63 are provided in a cross shape in the radial direction from the inner surface of the four parts 62 toward the outer circumferential surface of the lens holder B, and each air passage 63 is provided in a cross shape in the radial direction. Air passage (
Second, a back pressure measurement passage 65 is provided in a direction perpendicular to this, and a pressure sensor 66 is provided at the end thereof. Further, an air passage 67 is provided along the center line from the upper bottom of the recess 62, and an air suction pipe 68 is connected to the upper end. The outer diameter of the lens holder 60 is made slightly smaller than the inner diameter of the lens barrel 2, so that it can be easily inserted.

A hole 22 is bored on the side of the lens seat surface 21 of the lens barrel 2, passing through the lens barrel side wall.

A method for assembling a lens to a lens barrel using this device will be explained below. The bell part 6 of the lens holder O is on the top surface of the lens 1.
When the lens 1 is brought into contact with the lens 1 and the air inside the four parts 62 is sucked through the air suction tube 68, the lens 1 is attracted to the bell-shaped holding part of the lens boulder 6, and the air flows between the lens surface and the bell surface. 1 becomes easier to slide on the bell surface,
Due to the bell effect, the optical axis of lens 1 is automatically moved two times so that it coincides with the center line of the bell. On the other hand, hole 6 on the side of holder B
Air is sucked into the four parts 62 from the air passages 63 through the passages 63, and a negative pressure is generated depending on the gap between the side surface of the holder O and the inner surface of the lens barrel 2. It is detected by the pressure sensor 66 via the air passage 65. Based on this detection result, the center line of the lens holder B is made to coincide with the center line of the lens barrel 2 in the same manner as in the previous embodiment.

In this way, the optical axis of the lens is aligned with the center line of the lens barrel 2, so the lens 1 is held between the lens holder 6 and the lens seat 21 of the lens barrel 2, and the adhesive is injected from the hole 22 in the side wall of the lens barrel with a syringe. 42 to fix the lens 1 to the lens barrel 2. As in the previous embodiment, the adhesive can be supplied from within the holder depending on the shape and dimensions of the lens and lens barrel.

In the case of a method that sucks fluid from the outside to the inside of the bell as in this example, the airflow between the lens surface and the bell surface of the holder is In order to reduce formation and frictional resistance, the bell-shaped lens holder provided on the end face of the holder 7 is formed with three or more lens receiving surfaces 71, as shown in FIG. It is effective to form a small gap S between them.

Also, it is effective to slightly shake the lens during self-alignment due to the Bell effect. Appropriate methods for shaking the lens include slightly vibrating the lens holder or pulsating a fluid flowing between the bell surface and the lens surface.

Although air is generally used as the fluid flowing between the bell surface and the lens surface, it is not necessarily limited to this; for example, by assembling in an atmosphere of fluorocarbon gas, It can also be used to clean the lens surface, and cleaning and drying can be done instantly by continuously switching between Freon gas and general air. It is also possible to perform cleaning and drying using other gases or liquids.

According to the present invention, the optical axis of each lens constituting the lens system can be easily aligned with the center line of the lens barrel using the bell provided on the lens holder for assembly. Therefore, the optical axes of each lens are perfectly aligned, eliminating the need for lens centering, and the gap between the lens and lens barrel can be made gentler, making it easier to assemble the lens into the lens barrel. Furthermore, there is no need to provide a bell on each lens barrel, which is particularly effective in assembling small-diameter, high-precision lenses.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an example of an apparatus for carrying out the method of the present invention, FIG. 2 is a perspective view showing an example of a control section thereof, and FIG.
The figure is a sectional view showing another embodiment of the apparatus for carrying out the method of the present invention, and FIG. 4 shows the lens holding part of the lens holder of still another embodiment. It is a perspective view including an AS cross section. 1... Lens 2... Lens barrel 3, 6.7...
・Lens holder 39, 61.71...Bell-shaped lens holder agent Patent attorney Hisashi Ito, C. ・Jukushi ・ 1.1
(Meichi/, j7., Fig. 4 21'1 ζ゛shi3 f, l-i' ・, °・4 j, 'jl 37

Claims (1)

[Scope of Claims] (1) A lens assembly method in which a plurality of lenses constituting a lens system are installed in a lens barrel with their optical axes aligned with each other,
A means that can be inserted into the inner surface of the lens barrel with a gap and measures the deviation between the central axis of the lens barrel and the center axis of the lens barrel, a means that matches the two based on the result, and a bell provided concentrically at one end of the means. A lens holder having a shaped lens holder holds the lenses constituting the lens system one by one in the lens holder, and the Bell effect is achieved by flowing a fluid such as air between the bell surface and the lens surface. Align the optical axis of the lens with the central axis of the lens holder, and align the central axis of the lens holder with the central axis of the lens barrel (-) to align the optical axis of the lens with the central axis of the lens barrel. A lens assembly method characterized by fixing it to the lens barrel and aligning the optical axes of each lens composing the lens system in a straight line. (2) The central axis of the lens holder and the mirror in 5. above. The means for measuring the deviation from the center axis of the lens holder is an air micro-type measurement that utilizes the fluid back pressure generated by flowing fluid between the inside of the holder and multiple holes provided on the outer circumferential surface of the lens holder. The lens assembling method according to claim 1, characterized in that the lens assembling method is characterized in that the lens assembling method according to claim 1 is characterized in that the lens assembling method uses A method for assembling a lens according to claim 1, characterized in that a differential transformer type probe is used. The means to reduce the deviation to V,':;11j is h + d 7
The method for assembling a lens according to claim 1, characterized in that the method uses an "In'J:r" constant. (5) The lens holding section creates a negative pressure inside the bell. According to claim 1, the optical axis of the lens is aligned with the central axis of the holder by a bell effect caused by an opening for flowing fluid between the bell surface and the lens surface, and the lens is held by adsorption. (6) The above bell-shaped lens holding part has six or more small lens receiving surfaces, and the remaining part is formed so as to form a slight gap with the lens surface. A method for assembling a lens according to claim 5, characterized in that (7) the lens holder is made to vibrate minutely so that the light -11 of the lens coincides with the central axis of the holder; The method for assembling a lens according to claim 1. (8) When aligning the optical axis of the lens with the central axis of the holder, the fluid flowing between the bell surface and the lens surface is pulsated. The lens assembly method according to claim 1. (9) The lens assembly according to claim 1, wherein the fluid flowing between the bell surface and the lens surface is fluorocarbon gas. Attachment method.