JPH11211962A - Television lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the unstableness of zoom operation by varying constant the field angle variation rate when the signal outputted from a zoom speed signal output means is made constant. SOLUTION: Movement quantity signals of a wide-angle side movement point, a telephoto side movement point, and an intermediate movement point outputted from a zoom lens field angle variation rate determination switch are inputted to a CPU, which outputs the Y-directional movement signals of the wide-angle movement point W1 and telephoto side movement point T1 and the X-directional movement signal of the intermediate movement point C1 to a display unit 17 as shown by a field angle variation rate line L1 according to the input signals. The display unit 17 moves the wide-angle movement point W1 and telephoto side movement points T1 in the Y direction and the intermediate point T1 in the X direction according to the inputted signals. Then the CPU calculates a line passing the wide-angle side movement point W1, telephoto side movement point T1, and intermediate point movement point C1 to find an arithmetic expression determining the relation between the focal length and field angle variation rate, and a signal for displaying the line is outputted to the display unit 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a television lens for performing servo control of a zoom portion.

[0002]

2. Description of the Related Art Conventionally, as a zoom speed control device for a television lens or the like, as disclosed in, for example, Japanese Patent Application Laid-Open No. S51-40924, a zoom operation of a television lens is controlled by a driving system such as a motor and this driving system. A zoom speed signal output device is used to provide a command signal to a control system in the servo means. That is, as shown in FIG. 7, the signal output from the zoom speed signal output device 1 drives the lens driving circuit 3 via the zoom signal amplifying circuit 2.

[0003]

However, in the above-described conventional example, since the change in the angle of view when the mechanical change amount of the zoom lens is constant is not constant, the output from the zoom speed signal output device 1 is provided. However, there is a disadvantage that the image does not change at a constant rate of change in the angle of view from the wide-angle end to the telephoto end when the signal is constant.

For example, if it is desired to always perform an operation of decreasing the angle of view change of the zoom lens on the wide angle side and increasing it on the telephoto side, it is necessary to change the output signal from the zoom speed signal output device 1. However, there is a problem that it is difficult to maintain the stability of this signal.

An object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide a television lens capable of performing a stable zoom operation.

[0006]

In order to achieve the above object, a television lens according to the present invention provides a zoom lens having a fixed output signal from a zoom speed signal output device. The relationship can be changed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in FIGS. FIG. 1 shows a block diagram of a zoom speed control device for a television lens or the like according to the first embodiment. The output of a zoom speed signal output means 11, the output of a zoom lens position detector 12, and the rate of change of the zoom lens angle of view are determined. The outputs of the switches 13 are connected to the CPU 14 respectively. The output of the CPU 14 is the zoom signal amplifying circuit 1
The display 14 is connected to the zoom lens drive circuit 16 via the control unit 5 and the CPU 14 can visually grasp the relationship between the focal length and the change in the angle of view.

FIG. 2 is a front view of the zoom lens angle-of-view change rate determination switch 13, which can output the amount of movement in the X and Y directions. 3 and 4 show display examples of the angle-of-view change rate lines, in which the horizontal axis represents the zoom focal length and the vertical axis represents the angle-of-view change rate.

In the television lens having the above structure, the movement signals of the wide-angle side moving point, the telephoto side moving point, and the intermediate moving point output from the zoom lens angle-of-view change rate switch 13 are input to the CPU 14. Based on the signals, as shown in the view angle change rate line L1 in FIG. 3, the Y-direction movement signal of the wide-angle movement point W1 and the telephoto-side movement point T1 and the X-direction movement signal of the intermediate movement point C1 are displayed on the display 17. Output to The display 17 displays the moving point on the wide-angle side in FIG. 3 based on the input signal.
W1 and the telephoto-side moving point T1 are moved in the Y direction, and the
Is moved in the X direction. Then, the CPU 14 calculates a line segment passing through the wide-angle side moving point W1, the telephoto side moving point T1, and the intermediate moving point C1, and obtains an arithmetic expression for determining the relationship between the focal length and the angle of view change rate. A signal to be displayed is output to the display 17.

FIG. 4 shows an embodiment at this time, in which the wide-angle moving point W1 and the telephoto-side moving point T1 move to a place having the same angle-of-view change rate as the intermediate moving point C1, and the moving points are, for example, W2, T2, At a position like C2, the angle-of-view change rate line L1 is constant
Thus, an arithmetic expression that determines the relationship between the focal length and the rate of change in the angle of view such that the operation of the zoom lens has a constant rate of change in the angle of view is obtained.

Further, the wide-angle moving point W1 has a larger angle of view change rate than the intermediate moving point C1, and the telephoto-side moving point T1 has an intermediate moving point C1.
If the moving point is located at a position such as W3, T3, or C3, the angle of view line L1 becomes the angle of view line L3, and the zoom lens moves. Is obtained, an arithmetic expression that determines the relationship between the focal length and the angle of view change such that the rate of change of the angle of view on the wide-angle side increases and the rate of change of the angle of view on the telephoto side decreases.

Further, the wide-angle side moving point W1 has a smaller angle of view change rate than the intermediate moving point C1, and the telephoto side moving point T1 is the intermediate moving point C1.
If the moving point is located in a position such as W4, T4, C4 when the moving angle is larger, the angle of view line L1 becomes the angle of view line L4, and the zoom lens Is obtained, an arithmetic expression for determining the relationship between the focal length and the angle of view change such that the rate of change of the angle of view on the wide-angle side is reduced and the rate of change of the angle of view on the telephoto side is increased.

By doing so, the relationship between the focal length and the angle of view change can be visually grasped. When the signal from the zoom speed signal output unit 11 increases or decreases, the angle-of-view change rate line also increases or decreases in synchronization with the increase or decrease. Zoom speed signal output means 11 and zoom lens position detector 1
2 is input to the CPU 14 to calculate the angle of view change rate by an arithmetic expression that determines the relationship between the focal length and the angle of view change rate, and output a zoom speed signal based on the angle of view change rate and the position of the zoom lens. Is determined, and the zoom lens driving circuit 16 is driven via the zoom signal amplifying circuit 15.

As described above, in this embodiment, the function of changing the relationship between the focal length and the rate of change in the angle of view when the signal output from the zoom speed signal output means 11 is kept constant, and the relationship is visually determined. The instability of the zoom operation can be eliminated by providing means for changing the angle of view change when the signal output from the zoom speed signal output means 11 is kept constant.

FIG. 5 shows a block diagram of a zoom speed control device 11 of the second embodiment. In the first embodiment,
Although the output signal of the zoom lens angle-of-view change rate determination switch 13 is taken into the CPU 14, in this embodiment, as shown in FIG. It is configured to input to the CPU 14 and select an arithmetic expression that determines the relationship between the focal length and the angle of view change rate.

In the television lens constructed as described above, an output signal from the zoom lens angle-of-view change rate selection switch 18 is fetched by the CPU 14, and the CPU 14 uses the fetched signal to generate several kinds of signals prepared in advance. An appropriate one is selected from an arithmetic expression that determines the relationship between the focal length and the angle of view change rate. Then, a signal input from the zoom speed signal output means 11 and the zoom lens position detector 12 is applied to this arithmetic expression to calculate a rate of change of the angle of view, and the output is calculated based on the rate of change of the angle of view and the position of the zoom lens. The zoom speed signal to be used is determined, and the zoom lens driving circuit 16 is driven via the zoom signal amplifying circuit 15.

As described above, in the present embodiment, the function of changing the relationship between the focal length and the angle of view change when the signal output from the zoom speed signal output means 11 is kept constant, and the relationship is visually determined. The instability of the zoom operation can be realized by changing the angle of view change when the signal output from the zoom speed signal output unit 11 is fixed by providing a unit that can perform the zoom operation.

[0018]

As described above, the television lens according to the present invention has the function of changing the relationship between the focal length and the rate of change in the angle of view when the signal output from the zoom speed signal output means is constant. With this arrangement, the instability of the zoom operation can be eliminated.

[Brief description of the drawings]

FIG. 1 is a block circuit configuration diagram of a zoom speed control device according to a first embodiment.

FIG. 2 is a front view of a zoom lens angle-of-view change rate determination switch.

FIG. 3 is an operation explanatory view.

FIG. 4 is an operation explanatory view.

FIG. 5 is a block diagram of a zoom speed control device according to a second embodiment;

FIG. 6 is a front view of a zoom lens angle-of-view change rate selection switch.

FIG. 7 is a block diagram of a conventional zoom speed control device.

[Explanation of symbols]

 Reference Signs List 11 zoom speed signal output means 12 zoom lens position detector 13 angle-of-view change rate determination switch 14 CPU 15 zoom signal amplifier circuit 16 zoom lens drive circuit 17 display 18 angle-of-view change rate selection switch

Claims (4)

[Claims] 1. A television lens wherein a relationship between a focal length of a zoom lens and a rate of change of an angle of view when an output signal from a zoom speed signal output device is kept constant can be changed. 2. The television lens according to claim 1, wherein the relationship between the focal length and the angle of view change rate is an arithmetic expression. 3. The television lens according to claim 2, further comprising means for outputting a signal for changing the arithmetic expression. 4. The television lens according to claim 1, further comprising means for visually judging the relationship between the focal length and the angle of view change rate.