JPH0219812A - Optical element holder - Google Patents

Abstract

PURPOSE:To surely and stably hold a lens with plural lens frames without producing distortion in the lens by constituting an optical element-segment cell assembling body by sticking the plural lens frames having segment-like forms, namely, segment cells to the output periphery of the optical element and fixing the assembling body to a lens barrel. CONSTITUTION:Three pieces of segment-like segment cells 2 are arranged on the outer periphery of a lens 1 at equal angular intervals. Each the of segment cells 2 has a groove, namely, a pocket 4 and the pockets 4 forms a space 6 for housing adhesives for sticking the segment cell 2 to the lens 1 when the segment cell 2 is fitted to the lens 1. Therefore, the distortion which is produced when the lens 1 is directly fixed to a lens barrel 7 by means of a junk ring 8 does not occur in the lens 2 and the lens 1 can be held with a more accurate positional relation as compared to the case where layers of the adhesives are formed between the segment cells 2 and lens 1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical element holding device for fixing and holding an optical element such as a lens within a lens barrel.

Conventional technology The optical element holding device for fixing the lens to the lens frame includes:
Conventionally, there are various configurations. Among such prior art devices, devices for fixedly holding one lens or a group of lenses include (1) a lens barrel with a spacing ring or spacer for maintaining the distance between the lenses; A device in which the lenses are inserted alternately and finally fixed by tightening them with a retainer ring via an O-ring, etc. (2) A device in which the lenses are fixed by bonding the lenses to a ring-shaped lens frame with adhesive, etc. 3) There are devices in which a lens is fixed to a ring-shaped lens frame by caulking or other mechanical means.

Further, as a device for fixedly holding a plurality of lenses or a plurality of groups of lenses, there are the following: (1) A lens is inserted into a ring-shaped lens frame, and then a spacer ring or spacer is inserted into the mirror to maintain the distance between the lenses. (2) Insert a predetermined number of lenses into the lens barrel, and (2) insert a predetermined number of lenses into the lens barrel, and Finally, there are devices constructed by tightening with a presser ring.

When holding multiple lenses fixedly in this way, the device in which the lenses are fixed to a ring-shaped lens frame, etc. has already been measured for accuracy such as dimensional accuracy or alignment accuracy of the optical axis, and the spacing between each lens is measured. can be adjusted by adjusting a spacer interposed between the lens frames or by adjusting the lens frame itself.

Problems to be Solved by the Invention When a lens is subjected to an external force, it is deformed or distorted even if the external force is minute, resulting in a change in the optical characteristics of the lens. For example, devices in which a lens is tightened and fixed to a ring-shaped lens frame with a holding ring, and devices in which the lens is fixed to a ring-shaped lens frame by caulking or other mechanical means tend to apply external force to the lens, and It was extremely difficult to securely hold it with uniform force over the entire circumference.

In addition, a device in which a lens is fixed by bonding it to a ring-shaped mirror frame with an adhesive or the like makes the thickness of the adhesive layer between the lens and the ring-shaped mirror frame uniform over the entire circumference of the lens. If this is extremely difficult and the thickness of the adhesive layer is not uniform around the entire circumference of the lens, shrinkage of the adhesive during curing, or shrinkage of the adhesive after curing due to the influence of humidity or temperature. Due to expansion, the stress exerted on the circumference of the lens becomes uneven, deforming the lens and changing its optical performance.

As can be seen from the above, among the conventional devices, it is virtually impossible to fix the lenses to the ring-shaped lens frame without applying external force with the device that fixes and holds two lenses. It was also difficult to configure the lens to apply stress evenly over the entire circumference of the lens.

Among conventional devices, devices for fixing and holding a plurality of lenses have problems in addition to the above-mentioned problems that exist in devices for fixing and holding a plurality of lenses. When fixing the spacer between the lenses with a presser ring, it was unclear what kind of stress the spacer between the lenses would exert, which made assembly and adjustment difficult and required skilled techniques. have

Means for Solving the Problems An object of the present invention is to provide an optical element holding device that can securely and stably hold a lens on a lens frame without distorting it, and that can further facilitate lens assembly work. The goal is to provide the following.

According to the present invention, a plurality of segment-shaped lens frames, that is, segment cells, are adhered to the outer periphery of an optical element to form an optical element-segment cell assembly, and this assembly is fixed to the lens barrel. An optical element holding device is provided. Since the shape of the lens frame interposed between the lens and the lens barrel is not ring-shaped but segment-shaped, the stress exerted by the lens frame on the lens is reduced, and as a result, the distortion of the lens is reduced.

Embodiment An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

As can be seen from FIG. 2, three segment-shaped lens frames, ie, segment cells 2, are arranged around the periphery of the lens 1 at equal angular intervals. Grooves or pockets 4 are formed in these segment cells 2, as shown in FIG. When the segment cell 2 is attached to the lens 1, this pocket 4 forms a space 6 between the segment cell 2 and the periphery of the lens 1.
It is designed to house the adhesive that adheres to the

The adhesive is injected into the space 6 through the jack hole 3 which communicates the side of the segment cell 2 with the pocket 4 and the opposite side. The adhesive injected into the space 6 contracts slightly during curing and applies stress to the periphery of the lens 1. However, the width of the space 6, that is, the width of the pocket 4 is smaller than the thickness of the outer periphery of the lens 1, and the length of the segment cell 2, that is, the length of the pocket 4 is smaller than the circumferential length of the lens 1. Since the depth of the pocket 4 is small relative to its width, the volume of the adhesive accommodated in the space 6 is small and the contact area between this adhesive and the peripheral part of the lens 1 is very small. Since the layers are not continuous around the circumference of the lens 1, the stress applied to the circumference of the lens 1 is very slight and localized and does not substantially affect the optical properties of the lens 1. do not have.

The width, length and depth of the pocket 4 are selected taking into account the strength of the adhesive contained therein and the effect this has on the lens 1. When the segment cell 2 is removed from the lens 1, a removal jig, that is, a jack screw (not shown) is screwed into the jack hole 3.

Further, a protrusion 5 protrudes from the side of the segment cell 2 on which the pocket 4 is provided, and this protrusion 5 engages with the edge of the lens 1 to position the segment cell 2 in a predetermined relationship to the lens 1. useful for.

The lens-segment cell assembly constructed by the method described above, in which three segment cells 2 are arranged around the circumference at equal angular intervals, is inserted into the lens barrel 7, and then pressed with the presser ring 8. It is fixed inside the lens barrel 7 (see Fig. 1). At this time, the presser foot ff18 engages with the segment cell 2 and does not engage with the lens 1, so no stress is applied to the lens 1.

The lens barrel 7 may be provided with a push screw 9 for pressing the segment cell 2 radially inward at a position where the segment cell 2 is set. When this push screw 9 is provided, the lens-segment cell assembly can be fixed in the radial direction, and the optical axis alignment of the lens can also be adjusted during lens assembly.

When constructing a lens assembly using multiple lens-segment cell assemblies, if the distance between the lenses is narrow, a spacer is inserted between the lens-segment cell assemblies; on the other hand, if the distance between the lenses is wide, a spacer is inserted between the lenses. Alternatively, the distance between the lenses can be adjusted by cutting off the segment cells of the lens-segment cell assembly to reduce the thickness in the optical axis direction.

The above holding device can also be used to fixedly hold optical elements such as plane mirrors and optical filter prisms.

Effects of the Invention As can be seen from the above, according to the present invention, when a lens or the like is directly fixed to a ring-shaped lens frame by caulking or adhesive, distortions do not occur due to variations in caulking force or adhesive force, and , there is no distortion caused by directly fixing the lens to the lens barrel with the presser ring, and furthermore, since there is a part where the lens 1 and the segment cell 2 are in direct contact without using an adhesive, the segment cell 2 and the lens 1 are The lens 1 can be supported with a more accurate positional relationship than when an adhesive layer is sandwiched between the two. Furthermore, when configuring a lens assembly using multiple lenses,
Compared to conventional methods, high-precision assembly can be performed without using advanced skills or techniques.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a lens barrel in which a lens-segment cell assembly having segment cells according to the present invention on its periphery is accommodated, and FIG. 2 shows a lens barrel having three segment cells according to the present invention. 3 is a front view of a lens-'segment cell assembly arranged at equal angular intervals around the periphery, FIG. 3 is a detailed view showing a segment cell according to the invention, and FIG. FIG. 5 is a cross-sectional view showing a lens barrel in which a plurality of lens-segment cell assemblies each having segment cells on the periphery are housed, and FIG. FIG. 1...Lens 2...Segment cell 3
... Jack hole 4 ... Pocket 5 ... Protrusion 6 ... Space 7 ... Lens barrel 9 ... Push screw ... Holding ring

Claims (1)

[Claims] An optical element holding device characterized in that a plurality of segment cells are adhered to the outer periphery of an optical element to form an optical element-segment cell assembly, and this assembly is fixed to a lens barrel via the segment cells.