JPH0360404B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a lens holding device.

As a conventional lens holding device, as shown in FIG. A device that presses down with a ring of piano wire is often used. However, in this device, when a lens made of a material with a small Young's modulus, such as plastic, is used, surface deformation is likely to occur because a metal with a large Young's modulus comes into direct contact with the outer peripheral surface of the lens. Furthermore, since plastic has a larger coefficient of thermal expansion than metal, the lens expands to form a lens barrel, especially at high temperatures, and is susceptible to surface deformation when subjected to pressure.

As a countermeasure against this, Japanese Patent Application Laid-Open No. 57-138606,
Japanese Unexamined Patent Publication No. 57-141607 has been proposed. The invention disclosed in Japanese Unexamined Patent Publication No. 57-138606 provides a holding device for holding a plastic lens, which includes: a barreled portion formed on a lens support tube for holding the plastic lens; a pressing member for pressing the lens; an elastic member interposed between the barreled part and the holding member and formed of a material slightly softer than the hardness of the lens, so that the elastic member absorbs expansion of the lens or deformation of the lens due to contraction. This invention relates to a holding device for a plastic lens characterized in that the lens is held by pressing the lens, and the invention according to the above-mentioned Japanese Patent Application Laid-Open No. 57-141607 has a structure in which at least one of the front and rear surfaces of the lens and a lens holding member are used. The present invention relates to a lens fixing device that fixes a lens to a lens frame by forming a gap between the lens and the lens frame, and injecting and solidifying a soft filler into the gap.

Each of the above devices requires a lens holding member or an elastic member between the lens surface and the lens barrel mounting portion.

The present invention relates to the improvement of such a lens holding device, which eliminates the need for holding the lens with a holding member, and makes it possible to hold the lens more easily with an adhesive. The purpose of the present invention is to prevent deformation of the lens itself due to expansion or contraction of the lens, and
An object of the present invention is to provide a lens holding device in which a lens is fixed to a lens holding cylinder with an adhesive so that accurate positioning in the optical axis direction can be performed.

In order to achieve the above object, the present invention forms a space between a first protrusion provided on the outer periphery of the lens and an inner circumference of the lens holding cylinder, and forms a space closer to the center than the first protrusion of the lens. A second protrusion protruding in the optical axis direction is formed on the second protrusion, and with the second protrusion in contact with the optical axis reference surface of the lens holding tube, the first protrusion is aligned in the optical axis direction. A space is also formed between the radial surface of the second protrusion and the inner circumference of the lens holding cylinder, and the first The lens holding device is characterized by fixing the vacant position between the protrusion and the inner circumference of the lens holding cylinder with an adhesive whose Young's modulus is smaller than the material of the lens when solidified.

Embodiments of the present invention will be described in detail below with reference to the drawings.

2 and 3 show an example which is a premise of the present invention, FIG. 2 is a plan view, and FIG. 3 is a cross section in the _A1 - _A2 direction.

In the figure, 6 is a lens holding tube that stores and holds the lens 8, and is provided with a barreled portion 6a that holds the lens 8 against it. The lens 8 may have any shape, such as a spherical lens, an aspherical lens, or a flat lens, and has a contact portion 8a that contacts the barreled portion 6a. A gap t having dimensions to be described later is formed between the outer circumferential surface of the lens 8 and the inner circumferential surface of the lens holding cylinder 6. The lens 8 is fixed to the lens holding cylinder 6 by an adhesive 10 having a Young's modulus smaller than that of the material of the lens 8 during solidification.

For example, if the lens holding tube 6 is made of a metal material such as aluminum and the lens 8 is made of a plastic material, acrylic resin, phenol resin, urea resin, or polyester resin adhesives can be used. In this case, by using an ultraviolet curable adhesive, the assembly process time can be shortened.

Further, the use of a rubber adhesive as the adhesive also meets the purpose of the present invention.

FIG. 4 is a diagram illustrating the adhesive injection process. Since a gap is provided between the lens 8 and the holding cylinder 6 for the adhesive injection, the center line of the holding cylinder and the center of the lens 8 are A clamp device 12 is used to align the lens 8 to a predetermined position on the holding tube 6.
Use. Reference numeral 14 denotes an injection pipe for injecting adhesive into the gap.

In the present invention, it is desirable to select the gap between the outer circumferential surface of the lens and the inner circumferential surface of the lens holding cylinder according to the size of the outer diameter of the lens. ●When the outer diameter of the lens to be bonded is 6 mm to 20 mm: 0.05<t<0.3 (mm) ●When the diameter of the lens to be bonded is 20 mm or more 0.1<t<0.5 (mm) If the lower limit is exceeded, the amount of adhesive that enters the gap becomes too small and the adhesive force becomes weak; if the upper limit is exceeded, the adhesive strength It requires an excessive amount and is difficult to handle.

According to the above configuration, since a metal member having a large Young's modulus does not come into contact with the lens surface or its vicinity, the lens surface is hardly deformed. Furthermore, if the lens expands under high temperature, for example, if the outer diameter of the lens is about 20 mm and the environmental temperature goes from 20 degrees Celsius to 60 degrees Celsius, the diameter will increase by about 56 μm, but the diameter will increase by about 56 μm, but there is still enough space t to fill the adhesive. If the lens 8 is firm, the lens 8 will not come into contact with the holding lens barrel 6, and the pressure on the lens due to expansion will be absorbed by the adhesive 10, and no surface deformation will occur.

FIG. 5 shows an embodiment of the present invention, and shows an apparatus suitable for a lens having a relatively thin lens wall thickness compared to the lens outer diameter, a meniscus lens having a large curvature, and the like. When holding a lens with a thin wall thickness, it is desirable to fix the lens and the holding cylinder at a position as far away from the effective diameter of the lens as possible in order to avoid the effects of temperature changes. Therefore, in the example shown in FIG. 5, there is a partially flange-shaped protrusion 16a around the entire radial circumference of the outer circumferential surface of the effective aperture of the lens 16, and a partially flange-shaped protrusion 16a on the outer circumferential surface of the effective aperture, which is also on the center side. The flange-like protrusion 16b is formed all around or partially in the optical axis direction.
Reference numeral 18 denotes a lens holding cylinder that accommodates and holds the lens 16, and its dimensions are determined so as to form a predetermined gap depending on the outer diameter of the lens 16 between the lens 16 and the protrusion 16a. Lens holding tube 1
8 forms a barreled portion 18a against which the protruding portion 16b of the lens 16 in the optical axis direction abuts, and determines the fixing position of the lens 16 by this barreled portion.

The surface of the protrusion 16a provided on the outer periphery of the lens 16 in the optical axis direction and the surface of the lens holding tube 18 in the optical axis direction are not in contact with each other, and the protrusion 16b protrudes in the optical axis direction. A space is formed between the radial surface of the lens holding cylinder and the inner peripheral portion of the lens holding cylinder. The adhesive 10 has a protrusion 16a that protrudes in the radial direction.
The empty position between the lens holding cylinder 18 and the inner circumference of the lens holding cylinder 18 is fixed.

In the embodiment with the above configuration, the fixing position of the adhesive 10 and the positioning position in the optical axis direction are shifted,
Since the former is a protrusion 16a that protrudes in the radial direction, and the latter is a protrusion 16b that protrudes in the optical axis direction, the lens 16 does not tilt due to the adhesive 10 flowing in. That is, if the protrusion 16
When the surface of the lens holding tube 18 in the optical axis direction is brought into contact with the optical axis reference surface of the lens holding tube 18 for positioning, the adhesive 10 may flow from the outer periphery of the protrusion 16a to the surface position in the optical axis direction. The lens 16 will be tilted by the amount of adhesive 10 that has entered.
Moreover, the position in the optical axis direction is shifted. In this embodiment, positioning in the optical axis direction is performed by a protrusion 1 that protrudes in the optical axis direction.
6b, there is no adverse effect caused by the adhesive 10, so that a highly accurate position of the lens 16 in the optical axis direction can always be obtained without tilting.
Also, a protrusion 16b for positioning in the optical axis direction.
In the radial direction, since a space is formed between the lens 16 and the inner circumference of the lens holding cylinder 18, no problem occurs even if the lens 16 expands due to heat.

In the device configured as described above, by locating the fixing position away from the effective aperture of the lens, it was possible to avoid surface deformation of the lens due to temperature changes.

The example shown in FIG. 6 shows an improved device that is the basis for the embodiment shown in FIG. Here is an example of how to strengthen it.

In this example, the outer peripheral surface of the lens 20 and the lens holding cylinder 2 are
By forming notches 20a, 20a on the inner circumferential surface of the lens 2 for retaining the adhesive 24, the adhesive does not flow through the gap between the lens and the lens holding cylinder.

In FIG. 6, a notch 20 on the outer peripheral surface of the lens is shown.
a and the notch 22a on the inner peripheral surface of the lens holding cylinder are formed at positions facing each other, but their positions may be shifted or the notch on either the lens 20 or the lens holding cylinder 22 may be omitted.

7a to 7d show an embodiment of another improvement of the present invention, which proposes a device that can further avoid the effects of expansion and contraction effects due to temperature changes.

In the embodiment shown in FIG. 7, the lens 26 is attached to the lens holding tube 2.
The lens 26 is held in the lens holding tube 28 by bonding the adhesive to be bonded to the lens 26 between the outer circumferential surface of the lens and the inner circumferential surface of the lens holding tube 28 in a bridge-like manner. be.

In the figure, the outer periphery of the effective aperture of the lens 26 has a flange-like protrusion 26a similar to that shown in FIG. 5, and a protrusion 2 extending from the outer periphery of the effective aperture in the direction along the optical axis.
6b is provided. The lens holding cylinder 28 holds the lens 2
6, an inner circumferential surface 28a that provides a predetermined gap with the outer circumferential surface of the lens, a barreled portion 28b that abuts the protruding portion 26b of the lens, and an inner circumferential portion 2 in the radial direction of the protruding portion 26b.
8c and a flat portion 28d that connects the inner circumferential portion 28a and the inner circumferential portion 28c. As shown in FIG. 7B, the inner circumferential portion 28a of the lens holding cylinder 28 is provided with arcuate notches _28a1 at three approximately equally distributed locations. A feature of this embodiment is that the adhesive 30 inserted into the gap between the outer circumferential surface of the lens and the inner circumferential surface of the lens holding cylinder is inserted between the outer circumferential surface of the lens and the inner circumferential surface of the lens holding cylinder as shown in FIGS. 7a and 7b. Paste it so that it forms a shape,
Adhesion is made so that the adhesive does not get on the flat part 28d of the lens holding cylinder 28 in FIG. 7a. In order to achieve this, in addition to the above-mentioned configuration, the planar portion 28d shown in FIG. 7a is dug deeply, and the adhesive is made of a material with high granularity.

In FIG. 7c, the length of the bridge of the adhesive 30 is increased, and the protrusion of the lens 26 is increased in addition to the inner circumferential portion 28a of the lens holding cylinder 28 so that the strain stress of the lens 26 due to temperature changes can be absorbed. An arcuate notch is also formed in the portion 26a. Figure 7 d is
In order to obtain the same effect as in FIG. 7b, four arcuate notches _26a1 are formed in the protrusion 26a of the lens 26.

In the above embodiments, we mainly explained plastic lenses, but the situation is the same for ordinary glass lenses.
The present invention is useful as a lens holding device with less surface change.

As explained above, according to the lens holding device of the present invention that is fixed using an adhesive, it is possible to extremely minimize lens deformation when the lens is attached to a lens holding tube or at high temperatures.

Furthermore, in the present invention, adhesive is applied to the position of the protrusion provided on the outer periphery of the lens, and positioning in the optical axis direction is performed by the protrusion protruding in the optical axis direction. Highly accurate lens position without tilting or positional deviation can be obtained.

Further, in the present invention, a radial notch is formed in the inner diameter part of the lens holding cylinder or the radial protrusion of the lens, and the adhesive is applied to the notch position, thereby preventing the adhesive from accumulating. This prevents the lens from flowing in the circumferential direction, making it possible to achieve strong adhesion.

[Brief explanation of drawings]

FIG. 1 shows a lens holding device according to the prior art. Second
4 to 4 relate to a lens holding device showing an example as a premise of an embodiment of the present invention, FIG. 2 is a plan view, FIG. 3 is a cross-sectional view in the direction _A1 - _A2 of FIG. FIG. 6 is an explanatory diagram showing an example of holding the lens 8 in the lens holding tube 6. FIG. 5 is a sectional view showing an embodiment of the present invention. FIG. 6 is a plan view showing an example that is the premise of a further improved embodiment of the present invention. 7a to 7d show other embodiments of the present invention, FIG. 7a is a sectional view, FIG. 7b is a plan view, FIG. 7c is a partial plan view of an improved plan, and FIG. 7d
is a plan view of another improvement plan. 8, 16, 20...lens, 6, 18, 22...
...Lens holding tube.

Claims (1)

[Scope of Claims] 1. In a lens holding device in which a lens is fixed to a lens holding tube, an air space is formed between a first protrusion provided on the outer circumference of the lens and an inner circumference of the lens holding tube. and forming a second protrusion protruding in the optical axis direction toward the center side of the first protrusion of the lens, and aligning a surface of the second protrusion in the optical axis direction with the optical axis of the lens holding tube. The surface of the first protrusion in the optical axis direction and the surface of the lens holding tube in the optical axis direction are formed so as not to contact each other when in contact with a reference surface in the direction, and a space is formed between the radial surface of the second protrusion and the inner circumference of the lens holding tube, and the second protrusion is brought into contact with the reference surface of the lens holding tube. The empty position between the first protrusion and the inner peripheral portion of the lens holding cylinder is fixed with an adhesive whose Young's modulus is smaller than that of the material of the lens when solidified. A holding device for the lens. 2. In a lens holding device in which a lens is fixed to a lens holding tube, a space is formed between a first protrusion provided on the outer circumference of the lens and an inner circumference of the lens holding tube, and A second protrusion is formed that protrudes toward the center from the first protrusion in the optical axis direction, and a surface of the second protrusion in the optical axis direction is brought into contact with a reference surface of the lens holding tube in the optical axis direction. The surface of the first protrusion in the optical axis direction and the surface of the lens holding tube in the optical axis direction are formed so as not to contact each other when they are in contact with each other, and the diameter of the second protrusion is a space is formed between the directional surface and the inner peripheral part of the lens holding cylinder, and further, a plurality of empty positions are formed between the inner peripheral part of the lens holding cylinder and the first protrusion. A radial notch is formed at the location, and the first protrusion and the inner periphery of the lens holding tube are arranged in a state where the second protrusion is in contact with the reference surface of the lens holding tube. A holding device for a lens, characterized in that the empty position between the part and the notch position is fixed with an adhesive whose Young's modulus is smaller than that of the material of the lens when solidified. 3. In a lens holding device in which a lens is fixed to a lens holding cylinder, a space is formed between a first protrusion provided on the outer circumference of the lens and an inner circumference of the lens holding cylinder, and A second protrusion is formed that protrudes toward the center from the first protrusion in the optical axis direction, and a surface of the second protrusion in the optical axis direction is brought into contact with a reference surface of the lens holding tube in the optical axis direction. The surface of the first protrusion in the optical axis direction and the surface of the lens holding tube in the optical axis direction are formed so as not to contact each other when they are in contact with each other, and the diameter of the second protrusion is a space is formed between the directional surface and the inner circumferential portion of the lens holding cylinder; further, radial notches are formed at a plurality of locations on the outer circumferential portion of the first protrusion of the lens; In the empty position between the first protrusion and the inner peripheral part of the lens holding tube, with the second protrusion in contact with the reference surface of the lens holding tube. A lens holding device characterized in that the notch position is fixed with an adhesive whose Young's modulus is smaller than that of the material of the lens when solidified.