JPH09211497A - Transmission light adjusting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a light adjusting function work intantaneously by improving a response speed of an electrochromic device. SOLUTION: This device is provided with electrochromic device 102, a voltage driving means 107 to vary the transmittance of the electrochromic device by applying the voltage to it, and driving control means 104-106 to make the voltage driving means 107 apply to the electrochromic device a higher voltage than a target one for a specified time before applying the target voltage, in the process of varying the transmittance of the electrochromic device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitted light amount adjusting device using an electrochromic element and applied to an image pickup device such as a camera, and more particularly to an improvement in response speed in control.

[0002]

2. Description of the Related Art First, the operating principle of an electrochromic device will be briefly described.

An electrochromic device is disclosed in, for example, Japanese Patent Laid-Open No. 56-4679, and is shown in FIG.
It is an all-solid-state optical filter element having a variable spectral transmittance by voltage, having a structure as shown in FIG.

In FIG. 4, a transparent film electrode 5 such as lto is provided.
Between 01 and 502, an insulating film layer 50 such as Ta ₂ O ₅ or Sio ₂
3 through a colored oxide coloring film layer 504 and the reduction coloring film layer 505 such as lro _x, the transmission characteristic changes.

An electrochromic device having such characteristics has been proposed to be used in place of a diaphragm device such as a video camera or in combination with a diaphragm device. Due to its slow response speed, it has not been widely used. The operation response characteristic of the conventional electrochromic device is shown in FIG. 5 and will be described.

FIG. 5 shows the characteristics when the transmittance of the electrochromic device is lowered (the concentration is made higher).
The vertical axis represents the concentration of the transmittance of the electrochromic device (%)
The horizontal axis shows the time until the transmittance becomes stable (sec)
Is shown. The parameters are 0.5V, 1V, 2V, 3
The drive potential when V is applied is shown. For example, a transmittance of 7
In the case of 5% to 25%, when 1 V, which is a potential reaching the target transmittance, is applied, the response time until the target transmittance is reached takes about 2 seconds.

[0007]

As described above, even if the target transmittance achieving potential is applied to the electrochromic element in order to bring it to the predetermined target transmittance, the response speed of the electrochromic element is slow and the The diaphragm mechanism or the diaphragm assist mechanism is of poor practicality.

(Object of the Invention) In view of the above-mentioned circumstances, the present invention aims to provide a transmitted light amount adjusting device capable of improving the response speed of an electrochromic element and instantaneously exhibiting a light amount adjusting function. .

[0009]

In order to achieve the above object, the present invention according to claim 1 provides an electrochromic element and a voltage drive for changing the transmittance of the electrochromic element by applying a voltage to the electrochromic element. In the transmitted light amount adjusting device including means, in the voltage driving means,
In the process of changing the transmittance of the electrochromic element, a drive control means for applying a voltage higher than a target voltage to the electrochromic element for a predetermined time and then applying the target voltage is provided, and the response speed of the electrochromic element is adjusted. By applying a voltage higher than the target voltage, the improvement is made.

In order to achieve the above-mentioned object, the present invention according to claim 2 further comprises: a drive control means, a light quantity control potential output means for guiding the transmittance of the electrochromic element to a target value, and the light quantity control potential output means. When the output changes, the pulse generating means outputs a pulse signal for a predetermined time, and the adder which adds and outputs the output signal of the light quantity control potential output means and the pulse signal.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments.

FIG. 1 is a block diagram showing a configuration when the present invention is applied as a transmitted light amount adjusting device of a video camera.

In FIG. 1, light incident from the outside is condensed by a lens 101, passes through an electrochromic element (hereinafter abbreviated as EC) 102, and reaches a light amount detection means 103 such as a CCD or an image pickup tube. . The light amount detected here is converted into an electric signal, and the light amount control means 10 is provided.
4 is output. The light amount control means 104 compares appropriate amounts of the light signals, and outputs a light amount control signal to the adder 105 and the pulse generator 106 so as to receive a constant light amount. The pulse generator 106 generates a pulse signal having a width of several hundred msec in synchronization with the rising of the output change of the light amount control signal, and outputs the pulse signal to the adder 105. The adder 105 adds the light amount control signal and the pulse signal, and inputs the added signal to the voltage driving means 107 of the EC 102. This addition signal has an output potential twice as large as the light amount control signal by the initial time pulse signal width (several hundreds of msec), and the voltage driving means 1
07, the voltage driving means 107 outputs so as to respond quickly to the transmittance change response of the EC 102, and eventually the light quantity detecting means 103 is controlled so as to obtain a necessary predetermined light quantity.

Next, the flow of each signal will be described with reference to the time chart in FIG.

FIG. 2 (a) is a signal for determining the cycle of the timing for repeating the control explained in FIG. 1, and for example, the vertical synchronization V generated from the camera circuit of the video camera.
The light amount control is updated in synchronization with the cycle of an integral multiple of the H signal.

FIG. 2B shows a light amount control signal output from the light amount control means 104, which has + and − potentials centered on the reference potential Vr so as to keep the amount of light received by the light detection means 103 constant. Swing to. The concentration of the EC 102 thus changes the direction of the voltage applied to the EC 102 to change the transmittance.

FIG. 2C shows a pulse signal output from the pulse generator 106, which is synchronized with the rising edge of the light amount control signal and has the same potential amount as the output potential of the light amount control signal.
Moreover, it is output with a pulse width of several hundred msec.

FIG. 2D shows an output signal (addition signal) from the adder 105 which is synthesized from the light amount control signal and the pulse signal.

The change in transmittance of the EC 102 is controlled by this addition signal applied via the voltage driving means 107.

As described above, in the initial period of the change in the transmittance of the EC 102, a potential higher than the drive control potential determined by the light amount control signal is applied to the EC 102 for several hundred msec. Can react.

An enlarged view of the signal waveform showing the reaction at this time is
As shown in FIG.

FIG. 3A shows the case where the conventional light amount control signal is directly output to the voltage driving means 107 and applied to the EC 102. In this case, the EC1 shown in FIG.
The response time t1 (for example, 2 sec) until the target transmittance of 02 is reached is obtained.

On the other hand, in the present embodiment, FIG.
As shown in FIG. 3, the light amount control signal is varied so that a voltage higher than the control potential (for example, double potential) is applied during the initial driving period (for example, 500 msec).
As shown in (d), the response time of the EC 102 is t2 (for example, 1 sec), and t1> t2, and the response time is improved.

In the above embodiment, one pulse is generated by the pulse generator 106, but a plurality of pulses may be generated in time series. An example in which two pulses are generated is shown in FIGS. 3 (e) and 3 (f). EC1
Depending on the individual characteristics of 02, the correction of the initial drive may be more stable due to the change in transmittance.

Here, how the response time is improved will be repeatedly described with reference to FIG.

In order to quickly change the target transmittance from 75% to 25%, in this embodiment, the initial driving period is 500 m.
For about sec, the applied potential 2V with the target transmittance of 10% is once applied, and then the applied potential 1V with the target transmittance of 25% is applied.

Therefore, the response time of the EC 102 can be shortened, and even if the EC 102 is used instead of the diaphragm device such as a video camera, or in combination with the diaphragm device, there is no problem as a product.

(Modification) In the above embodiment, the EC 102 was used as a substitute for the diaphragm mechanism of the video camera.
You may use it together with the conventional diaphragm mechanism.

Furthermore, in the above-mentioned embodiment, the application to the video camera is shown, but the present invention is not limited to this. For example, a silver halide camera in which the light entering through the EC 102 is a photosensitive material may be used.

[0030]

As described above, according to the present invention,
It is possible to provide a transmitted light amount adjusting device that improves the response speed of an electrochromic element and instantly exhibits a light amount adjusting function.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment in which the present invention is applied as a transmitted light amount adjustment device for a video camera.

FIG. 2 is a time chart of the output waveform of each part of FIG.

FIG. 3 is a partially enlarged view of the output waveform of FIG.

FIG. 4 is a configuration diagram of an electrochromic device (EC).

5 is a diagram showing response characteristics of the electrochromic device (EC) of FIG.

[Explanation of symbols]

 102 electrochromic element (EC) 104 light quantity control means 105 adder 106 pulse generator 107 voltage drive means

Claims (2)

[Claims] 1. A transmitted light amount adjusting device comprising an electrochromic element and a voltage driving means for changing the transmittance of the electrochromic element by applying a voltage to the electrochromic element, wherein the voltage driving means includes the electrochromic element. In the process of changing the transmittance, the drive amount control device for applying a voltage higher than the target voltage to the electrochromic element for a predetermined time and then applying the target voltage is provided. 2. The drive control means, a light quantity control potential output means for guiding the transmittance of the electrochromic element to a target value, and a pulse generation means for outputting a pulse signal for a predetermined time when the output of the light quantity control potential output means changes. And an adder for adding and outputting the output signal of the light quantity control potential output means and the pulse signal.
The transmitted light amount adjusting device described.