JPH06235853A - Supporting method for lens and lens barrel used therefor - Google Patents

Abstract

PURPOSE:To shorten manufacturing time of a lens barrel, and to reduce a manufacturing cost by inserting a lens into a lens barrel formed of materials having an elastic force, elastically deforming the lens barrel into a shape corresponding to the shape of the lens, and supporting the lens. CONSTITUTION:Lens A-D are inserted into a lens barrel 2 formed of the materials having the elastic force, and the lens barrel 2 is elastically deformed into the shape corresponding to the shape of the lens A-D, so that the lens A-D can be supported. Then, the lens barrel 2 is formed by the materials having the elastic force so as to be deformed according to the shape external of the lens A-D to be supported. Also, the inner diameter of the manufactured lens barrel 2 is set smaller than the outer diameter of the lens A-D to be supported, and the elastic lens barrel of the lens barrel 2 are elastically deformed into the shape corresponding to the external shape of the lens A-D, so that the lens A-D can be integrated and supported. Therefore, the assembling precision of the lens A-D for fulfilling a desired optical performance can be easily secured, a size permission range can be extremely enlarged, and size correction after manufacture can be hardly necessitated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens supporting method and a lens barrel used therefor.

[0002]

2. Description of the Related Art In recent years, large-screen televisions have become widespread in homes, but when the screen is 40 inches or more, C
Projection televisions configured to magnify and project an RT image with a projection lens have become mainstream.
FIG. 1 is a schematic sectional view showing a lens barrel that supports a projection lens of a projection television, and shows a case where the projection lens is composed of a plurality of lenses. The barrel 1 includes an inner barrel 2 that supports the projection lenses A to D, and an outer barrel 3 that holds the inner barrel 2. The inner cylinder 2 is movable inside the outer cylinder 3 in the optical axis direction of the lens groups A to D (direction of arrow S), whereby the position of the projection lens can be adjusted for focusing. There is.

Since the projection lens of this projection television is a large-diameter lens with a diameter of approximately 100 mm or more,
The lens barrel for supporting the lens is required to have mechanical strength capable of withstanding the weight of the lens. Further, in order to satisfy the desired optical performance, it is necessary to match the optical axes of the lenses with each other, and assembling accuracy such as positioning of the lenses is required. For that purpose, it is necessary to process (manufacture) with high accuracy so that the inner diameter of the lens supporting portion of the lens barrel matches the outer diameter of the lens, and to obtain high shape accuracy. For this reason, the conventional barrel 1 uses metal materials or plastic materials having high mechanical strength for the inner barrel 2 and the outer barrel 3 and performs mechanical processing with high precision to obtain the required mechanical strength. The shape accuracy was obtained.

[0004]

However, it is difficult to manufacture a lens barrel (inner cylinder) that supports a lens with desired accuracy, and the size (inner diameter) of the lens supporting portion of the lens barrel and the outer diameter of the lens are different from each other. There were cases where they did not match. Therefore, it is necessary to set the manufacturing conditions of the lens barrel again and manufacture again. as a result,
For example, in the case where the lens barrel is manufactured by injection molding, the number of processes such as correction of a mold for injection molding is increased, which causes problems such as an increase in manufacturing time and an increase in manufacturing cost. Although it is conceivable to change the outer diameter of the lens, polishing and other steps are required for manufacturing and processing the lens, and in this case as well, problems such as an increase in manufacturing time and an increase in manufacturing cost cannot be avoided. The present invention aims to solve such problems.

[0005]

To achieve the above object, in the present invention, a lens is inserted into a lens barrel made of an elastic material, and the lens barrel is elastically deformed into a shape corresponding to the outer shape of the lens. The lens is supported by (Claim 1). For that purpose, the lens barrel is made of a material having elasticity so that it can be deformed according to the outer shape of the lens to be supported (claim 2).

[0006]

In the present invention, since the material of the lens barrel (inner cylinder) that supports the lens is elastic, even if the dimension (inner diameter) of the lens supporting portion of this lens barrel is different from the outer diameter of the lens to be incorporated. When the lens is inserted, the lens barrel is deformed according to the outer shape of the lens, so that the lens can be incorporated. That is, if the inner diameter of the lens barrel to be manufactured is set to be smaller than the outer diameter of the lens to be supported, the elastic lens barrel of the lens barrel is elastically deformed into a shape corresponding to the outer shape of the lens. Can be incorporated and supported. Therefore, it becomes easy to secure the assembling accuracy of the lens for satisfying the desired optical performance, and the dimensional allowable range is significantly expanded.

If the "thickness of the cross section perpendicular to the optical axis direction" of the lens barrel is made uniform at least in the circumferential direction of the lens supporting portion, the mirror when the lens is incorporated in the lens barrel is used. It is possible to make the outer shape of the cylinder correspond (similar) to the outer shape of the lens. Therefore, if the roundness of the lens to be supported is obtained with desired accuracy, the roundness of the lens barrel when supporting the lens can be made substantially equal to the roundness of the lens. In this case, if the lens barrel is manufactured by injection molding,
It is possible to make the wall thickness of the lens barrel substantially uniform regardless of the molding conditions.

As a material of the lens barrel of the present invention, a material having a tensile elastic modulus of 50,000 (kgf / cm ² ) or less is desirable, and as such a material, polycarbonate having a glass fiber filling amount of 10% or less, modified PPE, ABS resin, nylon, etc. can be used.

[0009]

1 is a schematic sectional view showing the structure of an embodiment of the present invention, which supports a projection lens of a projection television. In FIG. 1, a lens barrel 1 includes an inner cylinder 2 that supports the projection lenses A to D, an outer cylinder 3 that holds the inner cylinder 2, spacers 4 and 5 for positioning the lenses A to D at predetermined intervals. The holding ring 6 and the screw 7 for fixing the lens A to the inner cylinder 2 are provided, and the holding ring 8 and the screw 9 for fixing the lens D to the inner cylinder 2 are provided. The inner cylinder 2 has a screw hole M
Is provided integrally with at least two arms 2a, and a groove N is spirally formed in the outer cylinder 3. Then, the wing screw 11 is screwed into one of the screw holes M from the outside of the outer cylinder 3 through the washer 10 and the groove N to fix the inner cylinder 2 and the outer cylinder 3. A washer 12 fitted in the groove N of the outer cylinder 3 is fixed to the other arm 2a by a screw 13 so as to fix the inner cylinder 2 and the outer cylinder 3 and guide the inner cylinder 2 when rotating. Plays the role of. When the projection lenses A to D are moved in the optical axis direction (direction of arrow S) to perform focusing, the thumbscrew 11 is loosened and the inner cylinder 2 is rotated. Due to this rotation, the arm 2a moves along the groove N, and the inner cylinder 2 also moves in the optical axis direction accordingly. Therefore, the position of the projection lens can be fixed at the in-focus position by tightening the thumbscrew 11 at the in-focus position after the adjustment. The lens barrel 1 having such a configuration is used with the outer cylinder 3 attached to the main body of a projection television (not shown).

The inner cylinder 2 has a tensile elastic modulus of 50,000 (kgf /
made of elastic polycarbonate below cm ² )
It is manufactured by the injection molding method. As shown in FIG. 1, the inner cylinder 2 has an inner diameter set at a position for supporting the lenses A to D according to the outer diameter of the lens. Further, the rib 2b for fixing the lens and the step portion 2c are integrally formed. The size of the mold used for injection molding the inner cylinder 2 is set according to the outer diameter of the lens to be incorporated, and the shrinkage of the resin (polycarbonate) is not taken into consideration. However, the “wall thickness of the cross section perpendicular to the optical axis direction” of the inner cylinder 2 is set to be uniform in at least each lens support portion in the circumferential direction. In this case, the obtained molded product is smaller than the predetermined size as a whole due to the shrinkage of the resin and the relaxation of the molding distortion, but the thickness of the lens supporting portion is constant in the circumferential direction.

When the lenses A to D are incorporated in the inner cylinder 2, first, the lens C is placed on one side of the inner cylinder 2 (on the left side in FIG. 1).
And then push it in until it hits the rib 2b integrally formed on the inner cylinder 2. The inner diameter of the portion of the inner cylinder 2 where the lens C is incorporated and supported is slightly smaller than the outer diameter of the lens C before the lens C is inserted. However, since the inner cylinder 2 has elasticity, this support portion is elastically deformed according to the shape (outer shape) of the lens C when the lens C is inserted. As a result, the supporting portion of the lens C of the inner cylinder 2 supports the lens C in a state where the dimensional accuracy and the roundness of the lens C are substantially equal. Next, a spacer 4 having a predetermined length
Is inserted into the inner cylinder 2 to a position where it contacts the lens C, and then the lens B is pushed into the inner cylinder 2 to a position where it hits the spacer 4. At this time as well, when the lens C is inserted, the lens B of the inner cylinder 2
The dimensional accuracy and the roundness of the support portion are substantially equal to those of the lens B. Further, the spacer 5 having a predetermined length is inserted until it comes into contact with the lens B, and the lens A is pushed into the inner cylinder 2 to a position where it comes into contact with the spacer 5.
The support portion has substantially the same dimensional accuracy and roundness as the lens A. Then, the pressing ring 6 is fixed to the inner cylinder 2 with the screw 7, so that the lens A is sandwiched and fixed by the spacer 5 and the pressing ring 6. Thereby, the lenses A to C are completely fixed to the inner cylinder 2. The lens D is inserted from the side opposite to the lenses A to C (right side in the figure), and the stepped portion 2 integrally molded with the inner cylinder 2 is formed.
It was sandwiched between c and the retaining ring 8. At this time, lens A
As with C to C, the lens D support portion of the inner cylinder 2 has substantially the same dimensional accuracy and roundness as the lens D. The pressing ring 8 was fixed to the inner cylinder 2 with screws 9. In this way, the outer shape of the inner cylinder 2 in which the lenses A to D are incorporated is deformed corresponding to the outer shape of each lens that is incorporated and supported. It is almost equal to the circularity.

[0012]

As described above, according to the present invention, since the material of the lens barrel that supports the lens has elasticity, the dimension (inner diameter) of the lens built-in portion of the lens barrel is equal to the lens dimension (outer dimension). Even if the diameter is different from that of the lens, the lens is deformed according to the outer shape of the lens when the lens is inserted, so that the lens can be incorporated.
As a result, the dimensional tolerance during lens barrel manufacturing has expanded dramatically,
Almost no dimensional modification is required after manufacturing. As a result, the manufacturing time of the lens barrel is shortened and the manufacturing cost is also reduced.

Further, since the lens barrel itself has elasticity, it is possible to absorb external vibrations and impacts, and there is an advantage that the optical axis and the lens interval are less likely to change due to the vibrations and impacts.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing the configuration of an embodiment of the present invention.

[Explanation of symbols for main parts]

 1 lens barrel 2 inner cylinder (lens barrel in the present invention) 3 outer cylinder 4 spacer 5 spacer 6 retaining ring 7 screw 8 retaining ring 9 screw 10 washer 11 thumb screw A to D lens M screw hole N groove

Claims (2)

[Claims] 1. A lens support characterized by supporting the lens by inserting the lens into a lens barrel made of an elastic material and elastically deforming the lens barrel into a shape corresponding to the outer shape of the lens. Method. 2. A lens barrel, which is made of a material having elasticity and supports the lens by being deformed according to the outer shape of the lens to be supported.