KR20040107560A - Controller of zoom lens optical system - Google Patents

Abstract

PURPOSE: An apparatus for controlling a zoom lens optical system is provided to use a lens adjustment table suitable for temperature of a lens barrel as basic data for controlling a zoom lens and a focus lens, thereby accurately controlling zooming and focusing motions regardless of thermal transformation of the lens barrel by using at least two sorts of lens adjustment control tables in consideration of temperature of the lens barrel. CONSTITUTION: A lens barrel(10) has a plurality of lenses including a zoom lens(12) and a focus lens(14). An image signal captured by the lenses is converted into an electric signal by an image signal processing unit(20). A controller(30) detects an object by the electric signal and outputs a focusing region control signal and a driving control signal corresponding to the electric signal. More than two sorts of lens adjustment control tables in consideration of temperature of the lens barrel are stored in an EEPROM(Electrically Erasable and Programmable Read Only Memory)(40). The temperature of the lens barrel is detected by a temperature sensor(70) and is inputted into the controller. Herein, the controller selects a lens adjustment control table suitable for temperature of the lens barrel and uses the table to control the zoom lens and the focus lens.

Description

Zoom lens optical system controller {CONTROLLER OF ZOOM LENS OPTICAL SYSTEM}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens optical system used for a camcorder, a digital still camera, and the like, and more particularly, to a zoom lens optical system controller for controlling operations such as zooming and focusing of a zoom lens optical system.

The future development direction of the zoom lens optical system used in such a camcorder or a disc still camera is to simultaneously pursue high resolution and miniaturization. Therefore, the barrel of the optical system is inevitably downsized.

On the other hand, the miniature barrel is very sensitive to thermal changes, and for this reason, the miniaturized barrel can be easily deformed by external temperature changes. Such deformation caused by the external temperature of the barrel causes a change in the lens adjustment table, making it difficult to accurately control the zooming and focusing operation by the zoom lens optical system controller, which causes the lens to be out of focus and the resolution is reduced during lens adjustment. Is generated. Looking at it in detail as follows.

1 is a block diagram schematically illustrating a conventional zoom lens optical system controller. In the drawing, reference numeral 10 denotes a barrel, and inside the barrel 10, the front lens 11, the zoom lens 12, the relay lens 13, and the focus lens 14 are sequentially arranged from the object side. Here, the front lens 11 and the relay lens 13 are fixed so as not to move, while the zoom lens 12 and the focus lens 14 are installed to be movable along the optical axis direction for zooming and focusing.

Reference numeral 20 denotes an image signal processing unit, which converts an image captured by each lens in the barrel 10 into an electrical signal and inputs it to the control unit 30.

The control unit 30 receives the signal from the image signal processing unit 20 and controls the zoom motor driver 50 and the focus motor driver 60 by applying data from the lens adjustment table 41 stored in the EEPROM 40. do. Under the control of the control unit 30 as described above, the zoom motor 51 and the focus motor 61 are driven to move the zoom lens 12 and the focus lens 14 in the axial direction, thereby performing zooming and focusing.

Here, the lens adjustment table 41 stored in the EEPROM 40 tabulates data for moving each lens to a position where optimal performance can be achieved in consideration of manufacturing tolerances and assembly tolerances of the lenses. It is. The zoom lens optical system controller controls zooming and focusing on the subject to be performed automatically or manually by using the data of the lens adjustment table.

However, in the above general zoom lens optical system control apparatus, since one such lens adjustment table 41 calculated under ideal conditions without temperature change is stored in the EEPROM 40, the external temperature or the like is used. When the barrel 10 is deformed due to an increase in the temperature of the barrel 10, the lens adjustment table 41 is changed while the distance between the lenses is changed, thereby causing an error in lens adjustment as well as defocusing during manual zooming and resolution deterioration. There is a problem that needs to be improved.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and has at least two or more lens adjustment tables in consideration of thermal changes in the barrel, and applies an appropriate lens adjustment table according to the temperature of the barrel to provide an optical system irrespective of thermal changes in the barrel. An object of the present invention is to provide a zoom lens optical control device capable of precisely controlling the zooming and focusing operation of a digital camera.

1 is a block diagram of a general zoom lens optical system controller;

2 is a block diagram of a zoom lens optical system control device according to an embodiment of the present invention;

3 is a flowchart of a zoom lens optical system controller according to an exemplary embodiment of the present invention illustrated in FIG. 2.

<Description of Symbols for Main Parts of Drawings>

10; barrel 11, 12, 13, 14; lenses

20; image signal processor 30; controller

40; EEPROM 41, 42; First and second lens adjustment tables

50; zoom motor driver 60; focus motor driver

70; barrel temperature sensor

According to an aspect of the present invention, there is provided a zoom lens optical system controller, including: a barrel having a plurality of lenses including a movable zoom lens and a focus lens; An image signal processing unit for converting an image signal captured by a lens in the barrel into an electrical signal; A controller for inputting a signal from the image signal processor and outputting a subject detection determination and a focusing region control and driving control signal corresponding thereto; A zoom motor driver for driving a zoom motor in response to a driving control signal output from the controller; A focus motor driver for driving a focus motor by receiving a driving control signal output from the controller; An EEPROM storing at least two lens adjustment tables in consideration of thermal changes of the barrel applied as basic data of the focus lens and zoom lens control; And a barrel temperature sensor for sensing the temperature of the barrel and inputting it to the controller.

The controller selects a lens adjustment table suitable for the barrel temperature input from the barrel temperature sensor and applies the basic data of the focus lens and the zoom lens control. Therefore, even when the barrel expands and deforms due to temperature, accurate zooming and focusing operations can be controlled using the data of the second lens adjustment table considering this.

According to a preferred embodiment of the present invention, the two or more lens adjustment tables include a first lens adjustment table calculated at a reference temperature and a plurality of second lens adjustments respectively calculated according to a temperature change at a temperature higher than the reference temperature. Contains a table.

The plurality of second lens adjustment tables are calculated by adding compensation data for compensating for an error due to temperature change to the first lens adjustment table, and the reference temperature is set to about 50 ° C.

Best Mode for Carrying Out the Invention Preferred embodiments of the present invention will now be described based on the accompanying drawings. For reference, in describing the embodiments of the present invention, the same reference numerals refer to the same parts as those in the related art.

2 is a block diagram schematically illustrating a zoom lens optical system controller according to an exemplary embodiment of the present invention, and FIG. 3 is a flowchart of the zoom lens optical system controller according to the present invention.

As shown, the zoom lens optical system control apparatus according to an embodiment of the present invention, the front lens 11, the zoom lens 12, the relay lens 13 and the focus lens (in order) from the object side to the inside of the barrel (10) 14) are arranged at regular intervals. The zoom lens 12 and the focus lens 14 are moved in the optical axis direction by the zoom motor 51 and the focus motor 61, respectively, thereby performing zooming and focusing operations.

The image signal processing unit 20 converts the image signal captured by the lens in the barrel 10 into an electrical signal and inputs it to the control unit 30.

The controller 30 receives a signal from the image signal processor 20 as an input and outputs a subject detection determination and a focusing area control and driving control signal corresponding thereto. The zoom motor driver 50 drives the zoom motor 51 in response to a drive control signal output from the controller 30. The focus motor driver 60 drives the focus motor 61 in response to a driving control signal output from the controller 30.

The EEPROM 40 stores at least two lens adjustment tables 41 and 42 which are applied as basic data of the focus lens and the zoom lens control, and the controller 30 controls the lens adjustment tables 41 and 42. The data is controlled to control the zoom motor driver 50 and the focus motor driver 60.

According to a feature of the invention, the lens adjustment table (41) 42 has a first lens adjustment table 41 calculated at a temperature condition of, for example, 50 ° C or less, and a temperature at a temperature higher than the reference temperature. And a plurality of second lens adjustment tables 42, each calculated according to the change. The plurality of second lens adjustment tables 42 are calculated by adding compensation data for compensating for errors due to temperature changes to the first lens adjustment table 41. Although the drawings show an example in which the first to third lens adjustment tables are provided, the present invention is not necessarily limited thereto, and the lens adjustment table may be provided in larger numbers according to the characteristics of the optical system.

In addition, the zoom lens optical system control apparatus according to the present invention includes a barrel temperature sensor 70 for sensing the temperature of the barrel 10 and inputting it to the controller 30.

The controller 30 selects an appropriate lens adjustment table 41 or 42 corresponding to the barrel temperature detected by the barrel temperature sensor 70 and applies the data as the focusing and zooming control data. Looking at it as follows.

First, the temperature of the barrel is detected by the barrel temperature sensor 70 (S10). The controller compares the temperature T1 by the barrel temperature sensor 70 with the reference temperature T0 (S20), and when the condition of T0 <T1 is satisfied, the controller applies the first lens adjustment table to focus and zoom. To control (S30). On the other hand, if the condition is not satisfied, that is, if the barrel temperature is higher than the reference temperature T0, the controller compares the temperature T1 with an arbitrary temperature T2 again (S40). The second lens adjustment table is applied to control the focusing and zooming operation (S50). If the condition is not satisfied, the third lens adjustment table is applied to control the focusing and zooming operation (S60).

As described above, the zoom lens optical system control apparatus according to the present invention senses the temperature of the barrel and applies an appropriate lens adjustment table according to the temperature to control the focusing and zoom operation. By using the data to control the focusing and zooming operations, it is possible to prevent defocusing and resolution deterioration caused.

According to the present invention as described above, even in the case where the barrel is deformed by the external temperature, etc. in the zoom lens optical system having an ultra-small barrel, by applying a second lens adjustment table to which compensation data calculated in advance is added. Accurate zooming and focusing operations can be controlled.

Therefore, it is possible to prevent the focus shift and resolution deterioration at the time of lens adjustment caused by the thermal deformation of the barrel as in the prior art, thereby improving the reliability of the product.

While the invention has been shown and described in connection with the preferred embodiments for illustrating the principles of the invention, the invention is not limited to the construction and operation as shown and described. Rather, those skilled in the art will appreciate that many modifications and variations of the present invention are possible without departing from the spirit and scope of the appended claims. Accordingly, all such suitable changes and modifications and equivalents should be considered to be within the scope of the present invention.

Claims (4)

A barrel provided with a plurality of lenses including a movable zoom lens and a focus lens; An image signal processing unit for converting an image signal captured by a lens in the barrel into an electrical signal; A controller for inputting a signal from the image signal processor and outputting a subject detection determination and a focusing region control and driving control signal corresponding thereto; A zoom motor driver for driving a zoom motor in response to a driving control signal output from the controller; A focus motor driver for driving a focus motor by receiving a driving control signal output from the controller; An EEPROM storing at least two lens adjustment tables in consideration of thermal changes of the barrel applied as basic data of the focus lens and zoom lens control; And Includes; barrel temperature sensor for sensing the temperature of the barrel and input to the controller; And the controller selects a lens adjustment table suitable for the barrel temperature input from the barrel temperature sensor and applies the basic data of the focus lens and the zoom lens control. The method of claim 1, The two or more lens adjustment tables include a first lens adjustment table calculated at a reference temperature and a plurality of second lens adjustment tables calculated according to a temperature change at a temperature higher than the reference temperature. Optical system controller. The method of claim 2, The plurality of second lens adjustment tables are calculated by adding compensation data for compensating for errors due to temperature changes to the first lens adjustment table. The method according to any one of claims 1 to 3, The zoom lens optical system control device, characterized in that the reference temperature is 50 ℃.