JPH04212941A - Lens device - Google Patents

Abstract

PURPOSE:To enable a movable lens to have brake performance characteristic at an optimal position according to its kind. CONSTITUTION:Lenses constituting part of a lens system are movable lenses which move in the direction of an optical axis by lens driving means. The kind of such a movable lens is detected by a lens detection means 10. A signal from the lens detection signal 10 is inputted by a brake control means, so that the brake performance characteristic of braking a movable lens at its stroke end is changed. The braking position is thus changed according to the kind of a movable lens.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens device in which a movable lens of a lens system constituting a lens device such as a television camera unit is moved in the optical axis direction by a lens driving means, and in particular, the present invention relates to a lens device in which a movable lens of a lens system constituting a lens device such as a television camera unit is moved in the optical axis direction by a lens driving means. This relates to a braking mechanism.

0002

2. Description of the Related Art A lens device in a television camera unit is composed of a plurality of lens groups, and at least some of the lenses in this lens group are movable lenses in order to perform operations such as zooming and focusing. There is. This movable lens is normally configured to be driven by a lens drive means such as a motor, and the photographer has to operate the lens control means called a servo module attached to the lens device or the remote control device. The operation of each of these lenses is controlled by operating the means.

For example, a zoom lens is movable within a range from the wide side to the telephoto side, but when this zoom lens is driven by a motor, this It is necessary to stop the zoom lens without overrunning it. Moreover, it is necessary that the stop at this stroke end position be performed smoothly without any impact. For this purpose, a brake is attached to the motor control means, and the brake is configured to be activated at a predetermined position near both stroke ends described above.

0004

[Problems to be Solved by the Invention] Incidentally, depending on the mass of the lens, the inertial force when moving the lens differs. Since a large lens has a large inertial force, it is impossible to ensure a smooth stop at the stroke end position unless the brake is applied relatively early. On the other hand, a small lens has a small inertia, so if the brake is activated too early, it will be delayed to reach the end of the travel stroke, and the brake will be activated at a position very close to the end of the travel stroke. It is preferable from the viewpoint of responsiveness etc. In other words, the optimal brake operation start position differs depending on the type of lens. However, the prior art described above does not have a structure that changes the position at which the brake is activated depending on the type of lens. For this reason, the brake operating characteristics are not necessarily optimal, and are not desirable from the standpoint of protecting the lens and other equipment, as well as from the standpoint of operability of the lens device.

[0005] Here, it is possible to set the drive control circuit of the motor for driving the movable lens to have individual brake operation characteristics depending on the type of the movable lens. The configuration is limited to one in which the motor drive control circuit is built into the lens device, and the setting values of the brake operation characteristics of this drive control circuit are changed depending on the type of movable lens attached to each lens device. The problem is that it has to be done.

The present invention has been made in view of the above points, and its object is to provide a lens that can have brake operation characteristics at an optimal position depending on the type of lens. A driving device is provided.

[0007]

[Means for Solving the Problems] In order to achieve the above-mentioned objects, the present invention provides lens detection means for detecting the type of movable lens, and a method based on a signal from the lens detection means.
It is characterized by comprising a brake control means for changing the operating characteristics of the brake that performs a braking operation at the end position of the movement stroke of the movable lens, and having a configuration in which the brake operating position is changed depending on the type of the movable lens. be.

[0008]

[Operation] By adopting such a configuration, it becomes possible to provide optimum brake operation characteristics depending on the type of movable lens concerned, for example, its weight. That is, a plurality of control patterns are set in advance to achieve optimal brake operation characteristics depending on the mass of the movable lens, etc.
It is recorded in the brake control means. Here, the optimal brake operation characteristics are such that the movable lens stops smoothly at the stroke end position without any impact, but it also means that the brake is applied earlier than necessary and the movement is slow near the stroke end position. It is set so that it does not become. Therefore, among the plurality of brake operation characteristics set in this way, the one most suitable for the lens in question is selected. That is, when a brake control means is built into a lens device, settings are made so that a control pattern that provides optimum brake operation characteristics is selected depending on the type of movable lens in the lens device. In addition, if the lens control means or remote control device is provided with a brake control means, when they are connected to the lens device, the type of brake control means can be identified by ID (identification).
n) It is possible to detect the brake control pattern using a code or the like, and select the optimum one among the plurality of brake control patterns recorded in the brake control means based on the detection signal.

[0009]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, FIG. 1 shows a schematic configuration of a television camera unit. In the figure, 1 is the TV camera body, 2
indicate lens devices, respectively. As is well known, the lens device 2 is composed of a plurality of lenses, and some of the lenses in this lens system are movable for zooming, focusing, and the like. Therefore, in the following description, a zoom lens will be taken as an example of a movable lens.

As schematically shown in FIG. 2, in order to perform a zooming operation, the zoom lens 3 is moved in the optical axis direction, but this zooming operation is usually performed by rotating the cam cylinder 4. This is done by And this cam cylinder 4
Although the rotation can be performed manually, it is usually driven by a motor. For this purpose, the lens device 2 is provided with a lens control device 5 called a so-called servo module. Furthermore, it is also possible to connect a remote control device 6 in order to control the operation of the lens device 2 by remote control. Here, the zooming operation is to displace the zoom lens 3 in the range from the wide stroke end to the telephoto side stroke end, and the zoom lens 3 is
When an operation is performed to move the motor to this stroke end, it is necessary to perform a braking operation at the stroke end position in order to prevent overrun.

For this purpose, as shown in FIG. 2, a brake mechanism 7a is attached to the zoom lens drive motor 7, and this brake mechanism 7a controls its operation based on a signal from a brake control circuit 9. is configured to take place. This brake control circuit 9 is comprised of a braking characteristic setting device 9a and a braking characteristic selection means 9b. Here, in the braking characteristic setting device 9a, a plurality of braking characteristic patterns are set by patterning optimum braking characteristics for each type according to the type of zoom lens 3 in the lens device 2 attached to the television camera body 1. I'm letting you do it. For example, as shown by the solid line in Figure 3, the damping characteristics for a 20x zoom lens, and the characteristics for a 55x zoom lens shown by the dotted line, have optimal damping characteristics for several types of lenses. A braking pattern is set and recorded. Further, the braking characteristic selection means 9b selects the corresponding braking characteristic pattern from among the plurality of types of braking characteristic patterns recorded in the braking characteristic setting device 9a according to the type of the zoom lens 3 in the lens device 2 attached to the television camera body 1. This makes it possible to select a zoom lens 3 having optimal braking characteristics.

Here, the braking pattern selection by the braking characteristic selection means 9b is performed based on a signal from the lens detection means 10.

Specifically, if the lens device 2 is of a type in which the drive control circuit 8 and the brake control circuit 9 are built-in, the braking characteristic selection means is installed when the lens device 2 is installed. From among the plurality of braking characteristic patterns recorded in 9b, one having the optimum brake operating characteristic for the type of zoom lens 3 attached to this lens device 2 is selected and set in advance. In addition, a lens control device 5, a remote control device 4
If the drive control circuit 8 is provided in the drive control circuit 8, these may be connected to different types of lens devices. Therefore, in this case, the zoom lens 3 is placed on the lens device 2 side.
Lens detection is possible by providing means for displaying the type of lens, for example an identification code such as an ID code, and providing means for electrically or mechanically recognizing this identification code on the lens control device 5 and remote control device 4. Means 10
Configure. When the lens control device 5 or the remote control device 4 is connected to the lens device 2, the type of zoom lens 3 attached to the lens device 2 is recognized based on the signal from the lens detection means 10. By taking this signal into the braking characteristic selection means 9b, a brake operating characteristic that causes the brake to operate in an optimal state for this lens device 2 is selected.

As a result, when the lens device 2 is operated to operate the zoom lens drive motor 7 and move the zoom lens 3 to the telephoto side or wide side stroke end position, the corresponding The brake operates at the most appropriate position depending on the type of lens. Therefore, when the zoom lens 3 reaches the stroke end position, the zoom lens 3 stops extremely smoothly and does not experience any inconveniences such as being subjected to impact when stopped. There is no problem that the movement of the zoom lens 3 becomes extremely slow at certain positions.

As mentioned above, in the case where the brake control circuit 9 is incorporated in the lens control device 5 side or the remote control device 6 side, the type of lens is automatically detected by the lens detection means 10. Detect and
The optimum brake operating characteristics are selected accordingly. On the other hand, in the case of the type that is incorporated into the lens device 2, it is not necessarily necessary to detect the type of lens, and the type of lens can be set in advance.
There is no need to detect the type of lens during actual shooting. However, even with this type, it is convenient because the constituent members can be made common in constructing a brake control circuit 9 having an optimum brake control pattern for each type of lens device.

By the way, in general, the operation of the zoom lens 3 can be controlled by position control and speed control. Speed control is an operation to move the zoom lens 3 at a desired speed. Therefore,
Since the inertial force of the zoom lens 3 varies depending on this speed, it is necessary to change the brake activation position also depending on the moving speed of the zoom lens 3. That is, simply changing the brake operating position in proportion to the speed of the zoom lens 3 is not necessarily optimal.

Therefore, as shown in FIG. 4, the braking characteristic setter 20a constituting the brake control circuit 20 not only determines the brake operation characteristics depending on the type of zoom lens 3, but also determines the brake operation characteristics according to the speed of various zoom lenses. An optimal pattern of brake operation characteristics is set. The optimal brake activation position is then set depending on the type and speed of each zoom lens. That is, FIG.
As shown by the solid line a, stepwise according to the moving speed of the 20x zoom lens, or as shown by the dotted line b,
A brake operation timing characteristic that changes continuously is set, and also for a 55x zoom lens, the brake operation timing characteristic changes stepwise as shown by the dotted line c or continuously as shown by the dotted line d. It should have operation timing characteristics.

Then, by operating the operating means in the lens control device 5 or the remote control device 6, the zoom lens 3 is caused to perform a zooming operation, and when this zooming operation is performed by speed control, it is controlled by, for example, a potentiometer. , a speed detecting means 21 such as a volume, and this signal and a signal related to the type of zoom lens 3 detected by a lens detecting means 22 detecting the type of lens are sent to the characteristic selecting means 2.
0b, the optimum brake operating position set in the control characteristic setting device 20b is determined, and the brake is operated.

With this configuration, the brake is activated at the optimum timing when the zoom lens 3 is at the stroke end position on the wide side and telephoto side. That is, when using a heavy zoom lens and displacing it to the stroke end position at high speed, the brake is activated early to prevent overrun. On the other hand, if a lightweight lens is installed and this lens is displacing at a low speed, the brake will be activated very close to the end of the stroke, causing the brake to be activated earlier than necessary and causing the lens to move at a low speed. There is no inconvenience caused by the delay in moving to the desired position. Here, from the viewpoint of operability, etc., the zoom lens 3 is normally set to move at different speeds when moving toward the telephoto side and when moving toward the wide-angle side. Therefore, by setting the timing of brake operation according to the actual moving speed of the zoom lens 3, it is possible to perform a more optimal brake operation.

[0020] In each of the above-mentioned embodiments, the driving of a zoom lens has been described, but the present invention is also applicable to other systems other than this zoom lens, for example, a focus lens that is driven using a driving means such as a motor. Needless to say, it is possible. In addition, the brake control pattern is not limited to the two types shown in the drawings, but may be set as appropriate depending on the type of brake control pattern attached to the television camera body 1.

[0021]

As explained above, the present invention includes a lens detection means for detecting the type of movable lens constituting a lens system, and a detection means for detecting the movement stroke end of the movable lens based on a signal from the lens detection means. Since it is composed of a control means that changes the operation control characteristics of the brake that performs braking operation at the position, it is possible to exhibit the optimum brake operation characteristics depending on the type of movable lens, without sacrificing the operability of lens operation. Therefore, the stopping accuracy at the stroke end position of the movable lens is extremely good, and the movable lens can be stopped smoothly without being subjected to impact or the like.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing the overall configuration of a television camera device according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram of a lens control device.

FIG. 3 is a diagram showing a brake operation characteristic pattern.

FIG. 4 is a circuit diagram of a lens control device showing a second embodiment of the present invention.

FIG. 5 is a diagram showing a brake operation characteristic pattern.

[Explanation of symbols]

1 TV camera body 2 Lens device 3. Zoom lens 7 Zoom lens drive motor 8 Drive control circuit 9 Brake actuation means 9a Control characteristic setter 9b Characteristic selection means 10 Lens type detection means 20 Brake actuation means 20a Control characteristic setter 20b Characteristic selection means 22 Lens type detection means 21 Speed detection means.

Claims (2)

[Claims] 1. A lens system in which some of the lenses constituting the lens system are moved in the optical axis direction by a lens drive means such as a motor, comprising: a lens detection means for detecting the type of the movable lens; and a brake control means for changing the operating characteristics of a brake that performs a braking operation at an end position of the moving stroke of the movable lens based on a signal, and the brake operating position is changed depending on the type of the movable lens. Characteristic lens device. 2. The brake control means is set with a brake operation characteristic according to the type of the movable lens and the moving speed of each type of movable lens, and the brake control means is set with brake operation characteristics according to the moving speed of each type of movable lens, and the brake control means is set with brake operation characteristics according to the moving speed of each type of movable lens. 2. The lens device according to claim 1, wherein the actuation position of the brake is changed based on a signal from speed detection means for detecting speed.