JPS59204014A - Auto focusing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention provides an autofocusing device for a camera,
This invention relates to an O-I focusing device that controls the movement of a lens using a distorted bimorph.

A bimorph, which is one of the physical mechanical elements and exhibits high electrostrictive properties, is formed into an annular shape, and its bending distortion is used to directly extend and retract the lens, which eliminates the need for a conventional complicated mechanism. This makes it possible to easily control the focusing of the lens by controlling the voltage.

In the configuration shown in FIG. 1, L is a focusing lens, and ■ is a holding frame that holds a useless lens L.

Grooves 1a and 1b for accommodating pole or roller bearings are provided on the outer circumferential surface of both ends of the holding frame 1 in the optical axis direction to accommodate the bearings. Reference numeral 4 denotes a fixed cylinder, which holds the holding frame 1 movably in a direction parallel to the optical axis via the hole of the bearing or the roller 2. 6 and 8 are annular bimorph supporting members 10A-1
The outer peripheries of the annular bimorphs 6 and 8 are supported by the holding frame 1 from both ends in a sandwich-like manner through abutting portions 1cm1d fixed to the outer circumferential surfaces of both ends of the holding frame l. Configure. Bimorph 6 and 8
One side is bent in the forward direction, and the other side is bent in the opposite direction.

As shown in FIG. 3, although not shown in FIG. Configure it to do so.

1- Regarding the operation of the lens barrel configured as described in Fig. 2 (a) -
This will be explained with reference to (C). I1 from a known distance measuring device
- No. 1, (with respect to the subject imaging state: front focus, true alignment,
Detecting each state of the rear pin and detecting the front pin or the rear pin 4. i
When the applying means 14 is operated in response to "j-," in the case of FIG. 2(a), when a voltage is applied to the bimorph 8, the lens L is retracted in the direction of the arrow A.

Conversely, in the case of FIG. 2(C), when a voltage is applied to the bimorph 6 in response to the detection signal, the lens L is extended in the direction of arrow B. In the case of FIG. 2(b), an intermediate position is shown.

Figure 4(a) shows the applied voltage value (V) of bimorph 6I+8.
and displacement: t:(d).The voltage value (V) and the displacement amount (d) are in a proportional relationship, and the application means is applied according to the front pin and rear pin signals from the distance measuring device. By changing the output of 14, the amount of movement of the lens L can be controlled 111 to obtain a focused state.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a lens barrel according to an embodiment of the present invention. FIGS. 2(a), 2(b), and 2(c) are diagrams showing the driving state of the lens L. Figure S3 is a circuit diagram for applying voltage to bimorphs 6 and 8. FIG. 4(a) is a graph showing the relationship between applied voltage and displacement amount. FIG. 4(b) is a diagram showing the displacement state of bimorphs 6 and 8. 1-11-Lens holding frame 2---Tsukuda 1 ball or roller (roller) 6-8
----- Bimorph applicant Canon Co., Ltd. A
f3 Mochi Kasumi-V 謬 / 工 yen ≧ j (shi)

Claims (1)

[Claims] When a lens barrel that can be moved in the optical axis direction is tilted from both directions using an annular bimorph with an inverse piezoelectric effect, and a voltage is applied to each, the - force is deflected in the direction of the IL force, and the other is bent in the opposite direction. This is an O-I focusing device that extends and retracts the lens by reversing its characteristics and canceling out the load.