JPS5916650B2 - High-speed light intensity change observation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for accurately measuring rapid changes in light intensity.

High-speed light intensity changes, especially extremely short-time changes of several tens of microseconds or less,
Conventionally, to measure light impulses such as flashes of light, a special image pickup tube has been used that temporally resolves and detects the electron beam generated at the photocathode depending on the amount of light received, but its structure is complex. The price was high, and various peripheral devices had to be installed.

The present invention combines an electron tube that time-deflects incident light and a solid-state imaging device consisting of a photodiode array that corresponds to the trajectory of light emission points caused by the emission of the electron tube or the time-deflection of the observation window, and has a simple structure and excellent resolution. We aim to provide a light intensity change observation device.

FIG. 1 is a diagram showing the structure of the apparatus of the present invention, in which 51 is an electron tube for scanning light by deflecting an electron beam, 2 is an optical lens, and 3 is a solid-state imaging device.

The electron tube 1 includes an entrance window 4 at the top of the figure, an exit window 5 at the other end, a focusing electrode 6 surrounding the optical axis within the tube, and a pair of deflection electrodes 1 placed across the optical axis. ing. A photocathode 4a is formed inside the entrance window 4,
A counter electrode fluorescent screen 5a is formed inside the exit window 5.
The photocathode 4a is maintained negative with respect to the phosphor screen by the high-voltage power source E1, while the focusing electrode 6 is maintained at a lower potential than the photocathode 4a'5 by the power source E2. One of the pair of deflection electrodes 7 is maintained at the same potential as the photocathode 4a, but the other is controlled by a scanning potential that is applied to the terminal 11 and changes the potential of the photocathode up and down within a very short time. Thus arrow 8
When incident light, represented by , hits the θ photocathode surface of the entrance window 4, photoelectrons are emitted according to the amount of light, and the emitted electrons are turned into a focused beam by the focusing electrode 6 and directed toward the counter electrode phosphor screen 5a. Here, when a voltage is applied to the terminal 11 of the deflection electrode □, which rapidly changes from +V1 to -V1 with the cathode potential OV as the center, as shown in Fig. 2, this falling period T= is within 1 hour. The electron beam is deflected from the left end to the right end of the phosphor screen 5a in FIG. Second
In the figure, the deflection voltage begins to fall.

In reality, it is an extremely short delay time Td from the time of = 0.
The end point of the fall is the time td, which is past the time td.
Then, the time point when the delay time Td has passed is 1+d=+Td. In other words, the delay time Td is the average time it takes for the electron beam emitted from the photocathode to reach the deflection electrode 1, and therefore the electron beam enters the entrance window 4 from time = 0 to time tl. Only the portion corresponding to the incident light is deflected and scanned. In other words, see Figure 2, and see Figure 3 for details.
As shown in the figure, from the emission window 5 of the electron tube 1, due to the excited emission of the phosphor screen, a point emission with an intensity of 1(t) moving from point a on the left side to point b on the right side (from point a to right side) in a scanning time T is observed. The point light emitted from the window 5 is sequentially incident on the light-receiving zone a' to b' of the solid-state image sensor 3 by the optical lens 2.The front of the solid-state image sensor 3 (the light-receiving window is omitted) is shown in FIG. The photodiode array 3a is arranged along the length of the front of the rectangular main body, and inside the main body, although not shown, the photocurrent of each diode of the photodiode array is sequentially read out. A scanning circuit, a driving circuit for shifting the scanning circuit using an external start pulse and a clock pulse, and a noise diode array for canceling out mainly spike noise of photodiodes are incorporated.

Thus, in the solid-state image sensor 3, when the output of each photodiode successively located between a' and b' appears as a curve as shown in FIG. 5, the output signal changes between a' and B5. is incident on the electron tube 1 as it is t=o
It means the change in light amount in the time width T from t1 to time t1.

, / The apparatus of the present invention is as described above, and uses an electron deflection tube to perform accurate deflection scanning within an extremely short time that cannot be achieved by optical scanning means such as mirror operation, and a photodiode array to perform the scanning light emission. It has become possible to accurately detect points in microscopic time division units.

Furthermore, since the solid-state image sensor has the function of accumulating photoelectronic charges, its readout scan can be performed at a relatively low speed regardless of the deflection scanning speed of the electron tube, which is extremely advantageous for signal processing. Note that when the amount of incident light is small,
If an image amplifier is interposed between the observation window of the electron tube and the solid-state image sensor, measurement with higher sensitivity becomes possible.

[Brief explanation of the drawing]

Fig. 1 is a diagram schematically showing an embodiment of the present invention, Fig. 2 is a graph showing the deflection electrode voltage, Fig. 3 is a schematic diagram showing the surface of the electron tube exit window, and Fig. 4 is a main part of the solid-state image sensor. A front view showing
FIG. 5 is a graph showing the output curve of the solid-state image sensor. 1... Electron tube (electron beam type optical scanning tube), 2.
...Optical lens, 3...Solid-state image sensor,
3a...Photodiode array, 4...
... Entrance window, 5 ... Output window, 6 ... Focusing electrode, 7 ... Deflection electrode.

Claims (1)

[Claims] 1. An electron beam type optical scanning tube configured to deflect and scan a photoelectron beam emitted from a photocathode surface from one point on a counter electrode phosphor screen to another point; It is characterized by comprising a photodiode array arranged to correspond to the movement of point light emission to a point, and comprising a solid-state image sensor for generating an electric signal train corresponding to a change in the amount of received light within the scanning time. High-speed light intensity change observation device.