JPH04188103A - Liquid crystal diaphragm device - Google Patents

Abstract

PURPOSE:To be strong against shock and mechanical vibration and control the shape of the opening part optionally and quickly by providing a liquid crystal plate in which liquid crystal elements are arranged into grid and a transmitted light quantity of individual liquid crystal can be independently controlled. CONSTITUTION:A liquid crystal plate 1 in which liquid crystal elements 1a are arranged into grid and the transmitted light quantity of individual liquid crystal element 1a is independently controlled and a controller 6 to drive the liquid crystal plate 1 are provided, and it is constituted so that the liquid crystal plate 1 is equipped in the middle of an optical system and the shape of light transmitting part or the light transmission factor of the liquid crystal plate 1 is controlled by the signal from the controller 6. Namely, scanning voltage 7 and signal voltage 8 generated by the controller 6 are controlled so as to make the light transmitting part of the liquid crystal plate 1 into an optional shape. Hereby, a liquid crystal diaphragm device which is strong against shock and vibration and the shape of the opening part or transmission factor of the liquid crystal plate can be optionally selected, can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid crystal aperture device used in an imaging device or the like.

As is well known in the art, lenses used in cameras are typically equipped with an aperture device. This diaphragm device is usually called an iris diaphragm, and it continuously changes the size of the hole through which light passes.

A commonly used aperture device will be described below with reference to the drawings.

FIG. 5 is a plan view of a conventional mechanical throttle device. Fifth
In the figure, 11 is an arc-shaped blade (
Only one of them is shown), and pin 12 is placed on the front side of this, and pin 13 is placed on the opposite side. Here, the blade 11 can rotate around a pin 12. In addition, 14 is a rotating plate, which is provided with a guide groove.
A pin 13 is fitted therein so that the pin 13 can freely move within the guide groove.

The operation of the conventional aperture device configured as described above will be described below.

First, by rotating the rotary plate 14, the guide groove provided on the rotary plate 14 moves, and the pin 1 regulated by the guide groove
3 also moves. Therefore, the blade 11 rotates around the pin 12 as the pin 13 moves. Therefore, by rotating the rotary plate 14, in the conventional example shown in FIG. 5, five blades 11 are opened and closed all at once.

This system has a simple mechanism, and the rotation angle of the rotating plate 14 can be made proportional to the opening area of the diaphragm by adjusting the way the bins 12 and 13 are erected and the setting of the guide groove, and is generally used. However, using this method to create an arbitrary opening shape requires a large number of blades 11.

A diaphragm device using a liquid crystal element has been proposed in place of such a mechanical diaphragm device.

FIG. 6(a) is a configuration diagram of a camera using a conventional liquid crystal diaphragm device, and FIG. 6(b) is a diagram for explaining the operation of the liquid crystal diaphragm device (see Japanese Patent Laid-Open No. 619431). 6th
As shown in Figure (a), the camera has a lens 15 and a liquid crystal aperture device 16 arranged so that their optical axes 17 coincide, and a light ray 18 passes through this optical system to form an image on a photosensitive surface 19. There is.

Further, as shown in FIG. 2B, the opening 20 of the liquid crystal aperture device 16 is configured in a concentric circle shape, and opens and closes in a concentric circle shape depending on an applied voltage.

Problems to be Solved by the Invention However, the above-mentioned conventional mechanical aperture device uses thin metal plates, etc., so it is vulnerable to shock and vibration, and the opening shape can only be a polygonal shape close to a circle. There was a problem with this.

Furthermore, the conventional liquid crystal aperture device described above simply replaces the mechanical aperture device with a liquid crystal panel, and since the shape of the electrodes formed on the liquid crystal plate is concentric, the shape of the opening is also concentric. It simply opens and closes.

The present invention solves the above-mentioned conventional problems, and aims to provide a liquid crystal diaphragm device that is resistant to shock and vibration and allows the shape and transmittance of the aperture of the liquid crystal plate to be arbitrarily selected.

Means for Solving the Problems To achieve this object, the liquid crystal aperture device of the present invention comprises a liquid crystal plate in which liquid crystal elements are formed in a lattice shape, and the amount of transmitted light of each liquid crystal element is independently controlled; The structure has a drive device for driving this liquid crystal plate, the liquid crystal plate is installed in the middle of the optical system, and the shape or light transmittance of the light transmitting part of the liquid crystal plate is controlled by signals from the drive device. have.

Function: With this configuration, a diaphragm device that is resistant to shocks and mechanical vibrations can be obtained, and the shape of the opening can be quickly and arbitrarily controlled.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram using a liquid crystal aperture device according to an embodiment of the present invention. In FIG. 1, 1 is a liquid crystal plate of the present invention, 2 is a first imaging lens at the forefront, 3 is a second imaging lens at the rear, 4 is a photosensitive surface, and 5 is a subject. here,
The liquid crystal plate 1 according to this embodiment is placed between the first imaging lens 2 and the second imaging lens 3 at a position where the incident light does not form an image.

The operation of the imaging device using the liquid crystal plate of this embodiment configured as described above will be described below.

First, light coming from the subject 5 enters the first imaging lens 2. The amount of light is controlled by the liquid crystal plate 1, and the second
An image is formed on a photosensitive surface 4 through an imaging lens 3. Here, the liquid crystal plate 1 will be explained with reference to FIG.

FIG. 2 is a configuration diagram of a liquid crystal plate in one embodiment of the present invention.

In FIG. 2, 1 is a liquid crystal plate in which liquid crystal elements 1a are closely arranged in 6 rows and 6 columns, 6 is a controller for driving the liquid crystal elements 1a, 7 is a scanning voltage, 8 is a signal voltage, and 9 is an image pickup device. The attached switch 10 is an opening.

To explain the operation here, first, a trigger signal is generated by the switch 9 and sent to the controller 6.

The controller 6 generates a scanning voltage 7 and a signal voltage 8 based on the trigger signal.

FIG. 3 is a signal waveform diagram of the scanning voltage and the signal voltage. In this example, the scanning voltage 7 applies to the liquid crystal elements 1a, which are present in 6 rows and 6 columns.
This is a voltage that specifies which column is to be driven, and when the scanning voltage 7 of a certain row is on, that row becomes drivable.

The signal voltage 8 is a voltage that performs control to obtain the desired shape of the opening 10, and when the signal voltage 8 is on, the liquid crystal element 1a
transmits light, and when the signal voltage 8 is off, the liquid crystal element 1a blocks the light.

For example, when the time period is from O to t, only the first row scanning voltage 7 is on, so only the first row liquid crystal element 1a is in a drivable state.

Here, since the signal voltage 8 is all off from the first column to the sixth column, the liquid crystal elements 1a in the first row all block light. Also, if the time is from 2t to 3t, the third
Since only the row scanning voltage 7 is on, only the third row liquid crystal element 1a is in a drivable state. Here, the signal voltage 8 is on in the third and fourth columns and off in the other columns. Therefore, the liquid crystal elements in the third column and the fourth column of the third row transmit light, and the others block light. Similar operations are performed for the other rows, and in this example, a square light transmitting area is formed in the center of the liquid crystal plate.

In addition, by increasing the number of liquid crystal elements 1a,
A star-shaped opening 10 as shown in FIG. 4 can also be easily made.

In this manner, by controlling the scanning voltage 7 and signal voltage 8 generated by the controller 6, it is possible to form the light transmitting portion of the liquid crystal plate 1 into an arbitrary shape.

Effects of the Invention As described above, the present invention can eliminate mechanically moving parts by providing a liquid crystal plate in which liquid crystal elements are formed in a grid pattern and the amount of transmitted light of each liquid crystal element can be independently controlled. Furthermore, since the control is carried out electrically, it is possible to realize an excellent liquid crystal aperture device that can quickly and arbitrarily select the shape of the aperture. In addition, this liquid crystal aperture device can reduce the influence of light diffraction, but conversely, it is also possible to actively utilize light diffraction to produce special effects.

In addition, like a normal mechanical aperture device, it is possible to transmit only the central part of the incident light beam and block the peripheral part of the light beam, which reduces aberrations in the imaging lens and improves the depth of field. Adjustment is also possible.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an imaging device using a liquid crystal aperture device according to an embodiment of the present invention, Fig. 2 is a block diagram of a liquid crystal aperture device according to an embodiment of the present invention, and Fig. 3 is a diagram showing scanning voltages and signal voltages. FIG. 4 is a diagram showing the shape of the light transmitting part of the liquid crystal diaphragm device of the present invention, FIG. 5 is a plan view of a conventional mechanical diaphragm device, and FIG. FIG. 6(b), which is a block diagram of an imaging device using an aperture device, is a diagram for explaining the operation of the liquid crystal aperture device. 1...Liquid crystal plate, 1a old...liquid crystal element, 2...
...First imaging lens (optical system), 3...
2nd imaging lens (optical system), 6...controller (driver), 7...scanning voltage (signal),
8...Signal voltage (signal). Name of agent: Patent attorney Haruaki Koebi Two people Figure 1 (Optical system Figure 3/1AI Figure 5 (O) (b)

Claims (1)

[Claims] It has a liquid crystal plate in which liquid crystal elements are formed in a lattice shape and the amount of transmitted light of each liquid crystal element is independently controlled, and a drive device for driving this liquid crystal plate, and the liquid crystal plate is located in the middle of the optical system. 1. A liquid crystal aperture device installed in a liquid crystal aperture device, wherein the shape or light transmittance of a light transmitting portion of the liquid crystal plate is controlled by a signal from the driving device.