JPH043857B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a focusing device for an enlarged projection lens used in a projection television receiver or the like.

Conventional configurations and their problems In recent years, so-called projection televisions, which enlarge and project video images from a small cathode ray tube onto a screen through a projection lens to obtain a large screen, have rapidly become popular.

This projection television uses a large-diameter lens to make the projected image on the screen as bright as possible. In order to form a projected image on a screen at a predetermined position, it is necessary to adjust the focus of the lens after assembling the set.
Furthermore, after adjustment, the lens position must be securely fixed so that the focus does not shift.

An example of the conventional method is shown in FIG. In the figure, reference numeral 1 denotes an outer lens barrel, and an outer lens barrel 2 is disposed inside the outer lens barrel 1 so as to be slidable in the front and back direction. Concave grooves are formed at two locations on the front and back of the outer circumference of the outer lens barrel 2, and an O-ring 3 is mounted in the concave grooves. The outer shape of the O-ring 3 is in sliding contact with the inner wall of the outer barrel 1, and the inner barrel 2 is configured to slide back and forth inside the outer barrel 1 via the O-ring 3. In addition, the outer lens barrel 1
The O-ring 3 can be omitted if the inner diameter of the inner lens barrel 2 and the outer diameter of the inner lens barrel 2 are finished with high precision to obtain an appropriate fitting and sliding condition.

To perform focus adjustment, the inner lens barrel 2 is moved back and forth, the optimal lens position is determined while observing the image formation state on the screen, and the lens barrel is fixed at that position, but the conventional fixing method Now, as shown in FIG.
By screwing in a lock screw 4 and pressing its tip against the outer wall of the inner barrel 2, the movement of the inner barrel 2 in the front and back direction is restricted.

With the conventional fixing method as explained above,
By screwing in the locking screw 4, the inner lens barrel 2
The lens is slightly displaced in the way it is pressed by the locking screw 4, causing optical axis misalignment with other lenses, resulting in a decrease in resolution. Furthermore, if the inner barrel 2 is made of plastic material, screwing in the locking screw 4 will deform the inner barrel 2, causing deviations in the perpendicularity and relative position of the lenses.
This causes problems such as deterioration of lens performance and permanent deformation or cracking of the inner lens barrel 2 due to changes over time.

OBJECTS OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the conventional lens barrel fixing means as described above, and to provide a lens barrel fixing means that has a simple structure and high reliability.

Structure of the Invention The lens focusing device of the present invention includes an outer lens barrel, an inner lens barrel that is slidable back and forth inside the outer lens barrel, and a guide hole bored in the peripheral wall surface of the outer lens barrel. an operating lever formed on the outer wall surface of the endoscope barrel so as to protrude outward from the guide hole; and a lock bolt disposed to be fitted and guided in the guide hole, which has a through hole through which the operating lever penetrates. and a lock nut that is screwed together with this lock bolt, and by screwing the lock bolt and lock nut together, the outer lens barrel wall surface is clamped and movement along the guide hole is fixed, and when the lock bolt is fixed, the lock bolt The control lever inserted into the through hole formed in the control lever cannot be moved, and the control lever is erected, and the movement of the endoscope barrel that is moved by the operation of the control lever is also fixed. It is.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows a cross-sectional view of a projection lens employing an embodiment of the present invention. In the drawings, 11 is an outer lens barrel, and 11a is a guide hole bored in the wall of the outer lens barrel. An inner barrel 12 is disposed within the barrel of the outer barrel 11 so as to be movable back and forth and rotatable. An operating lever 12a is integrally formed so as to protrude outward from the wall surface of the inner barrel 12, and the operating lever 12a projects out of the outer barrel 11 from within the guide hole 11a. Concave grooves are formed at two locations on the front and back of the outer circumference of the inner lens barrel 12, and O-rings 13 are attached to the grooves. The outermost diameter part of the O-ring 13 is the outer lens barrel 1
The inner barrel 12 slides back and forth inside the outer barrel 11 via this O-ring 13. Note that the guide hole 11a is formed in a spiral shape in the wall surface of the outer lens barrel 11.

Reference numeral 14 designates a lock bolt, which has a through hole 14a formed in the center thereof through which the operating lever 12 penetrates, and is disposed so as to fit into and be guided by the guide hole 11a. A lock nut 15 is screwed onto the lock bolt 14 from the outside. 16 is the first lens attached to the outer lens barrel 11;
8 and 19 are the second, third and fourth parts attached to the endoscope barrel 12.
It's a lens.

A square seat 12b is formed at the base of the operating lever 12a as shown in FIG. 4, and a square hole 14b is formed in the bottom of the lock bolt 14 as shown in FIG.
is formed. When the lock bolt 14 is inserted into the operating lever 12a, the square seat 12b and the square hole 14
b engages to prevent idle rotation when the lock nut 15 is tightened.

Next, the operation of the embodiment configured as above will be explained. When the lock bolt 14 and the lock nut 15 are not tightened, the lock bolt 14 is movable along the guide hole 11a. When the operating lever 12a or the lock nut 15 is pinched to rotate the inner barrel 12 in the left-right direction, the inner barrel 12 rotates and moves back and forth since the guide hole 11a is formed in a spiral shape. While moving the inner barrel 12 back and forth in this manner, the optimal focus position is determined and fixed at that position.

The amount of movement of the inner barrel 12 back and forth relative to the rotation angle can be easily changed by arbitrarily setting the inclination angle of the spiral of the guide hole 11a.

To fix the inner lens barrel 12, tighten the lock nut 15, and clamp the outer lens barrel wall surface around the guide hole 11a with the lock nut 15 and lock bolt 14.
This is done by not moving inside a. Since the operation lever 12a formed integrally with the inner barrel 12 is fitted into the through hole 14a of the lock bolt 14, the inner barrel 12 cannot move in both the rotational direction and the front-rear direction, and the inner barrel 12 is fixed.

Note that in this embodiment, the guide hole 11a is formed in the outer lens barrel 11, but this is not limited to the outer lens barrel, and can also be applied to a part dedicated for installation such as a lens barrel holder. good.

Effects of the Invention As is clear from the above description, according to the present invention, a guide hole is formed in the outer lens barrel, and a lock bolt and a lock nut are fastened from the inside and outside of the outer lens barrel so as to sandwich the guide hole. , the locking bolt and the locking nut clamp the wall surface of the lens barrel around the guide hole, fixing the movement of the locking bolt and locking nut, and also fixing the movement of the inner lens barrel that moves in cooperation with the locking bolt, Unlike conventional locking devices, when the locking screw is tightened, force is applied to the inner lens barrel, causing it to deform, and there is no possibility of cracks or permanent distortion occurring over time. It is also possible to solve the problem that the lens performance deteriorates as a result of deviations in the relative positions such as the distance between the misaligned surfaces or the perpendicularity.

Furthermore, it can be fixed without using any special tools, and the two operations of adjusting the lens and tightening the lock nut can be performed with one hand, and there is no need to change hands, so it is extremely easy to work with, and focus adjustment work can be done quickly. Excellent effects can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of essential parts of a conventional lens focusing device, FIG. 2 is a cross-sectional view of a lens focusing device according to an embodiment of the present invention, FIG. 3 is a top view of its external appearance, and FIG. The figure is an enlarged perspective view of the operating lever portion, and FIG. 5 is a perspective view from the bottom side of the lock bolt. 1, 11...Outer barrel, 1a...Female thread, 11a
... Guide hole, 2, 12 ... Inner lens barrel, 12a ... Operation lever, 12b ... Square seat, 3, 13 ... O-ring, 4 ... Lock screw, 14 ... Lock bolt,
14a...through hole, 14b...square hole, 15...lock nut, 16, 17, 18, 19...lens.

Claims (1)

[Scope of Claims] 1. An outer lens barrel, an inner lens barrel installed to be movable back and forth inside the outer lens barrel, and a guide hole formed in a spiral shape in a peripheral wall surface of the outer lens barrel. , an operating lever integrally formed on the peripheral surface of the inner barrel so as to protrude from the guide hole, and a through hole into which the operating lever enters, and the operating lever is fitted into the guide hole and guided along the guide hole. What is claimed is: 1. A lens focusing device comprising: a lock bolt disposed such that the lens is locked; and a lock nut that is threadedly engaged with the lock bolt and clamps the wall surface of the outer lens barrel together with the lock bolt.