JPS5822728B2 - optical scanning device - Google Patents

Description

[Detailed description of the invention] The present invention relates to an optical scanning device.

For example, when attempting to reproduce an image of a test sample optically scanned by a scanning microscope on a monitor scope, a signal synchronized with the optical scan is required to drive the monitor scope.

For example, when a flat reflecting mirror is used to generate scanning light and is vibrated, a synchronization signal can be easily extracted from the electrical signal that drives the flat reflecting mirror.

However, when a rotating polygon mirror is used as a deflector, a synchronization signal cannot be extracted from the electrical signal that rotates the rotating polygon mirror.

Therefore, the applicant filed the earlier patent application No. 1981-170.
In this paper, we proposed a method that can extract a signal accurately synchronized with optical scanning even in cases where it is impossible to extract a synchronizing signal from the electric signal that drives the deflector that creates the scanning light.

In this method, a part of the scanning light at the end of the surface being optically scanned or a surface optically conjugate with the optical scanning surface is incident on a photoelectric element, and the photoelectric element generates a signal synchronized with the optical scanning. An example of this is shown in Figure 1.

In FIG. 1, a light source 1 emits a collimated light beam, such as a laser beam.

In this example, a rotating polygon mirror is used as the first deflector 2, and by rotating it, the light beam from the light source 1 is deflected in the horizontal direction.

The light beam reflected and deflected by the first rotating polygonal mirror deflector 2 is made incident on the second deflector 5 through a 1-magnification afocal lens system 3°4, and the second deflector 5 is a vibrating reflector or a rotating A polygon mirror is used to vibrate or rotate the mirror to vertically deflect the incident light beam.

By inserting the equal-magnification afocal lens systems 3 and 4 in this way, the eleventh and second deflectors can be separated, the second deflector 5 can be made smaller, and the second deflector 5 can be made smaller. The resulting light beam becomes a parallel light beam, and moreover, it is accurately two-dimensionally deflected.

In this way, the deflectors 2 and 5 allow 1
The deflected light beam passes through a relay lens 6 to a scanning surface 7.
The light is focused upward and scans the scanning surface 7 two-dimensionally.

A triangular prism 8 is arranged at the end of this scanning surface 7, and as shown in the figure, this is scanned with a part of the scanning light 9 at each scan. The light is reflected by the lens 10, and after being focused by the lens 10, it is made incident on the photoelectric element 11.

Therefore, a signal is generated from the photoelectric element 11 each time the scanning light 9 passes through the triangular prism 8.

Since this signal is in the form of a pulse and is synchronized with the optical scanning, it can be used as a synchronizing signal when reproducing the image of the object optically scanned with the scanning light 9 on the monitor scope.

However, since this method uses the edge of the scanning surface 7, it becomes necessary to scan a wider area than the actually necessary scanning area. This puts a burden on the optical system, and in particular requires the lens 6 to have a fairly wide angle of view, making it difficult to design and manufacture.

The purpose of the present invention is to enable a signal accurately synchronized with optical scanning to be easily extracted without putting a burden on the optical system even when a synchronizing signal cannot be extracted from the electric signal that drives the deflector that creates the scanning light. Our goal is to provide an optical scanning device with

The first scanning device of the present invention includes a first deflector made of a rotating polygon mirror for scanning in a first scanning direction, and a direction perpendicular to the first scanning direction, that is, a second scanning direction. a second deflector arranged to scan the first and second deflectors;
an equal magnification afocal lens system in which first and second lenses are arranged from the first deflector side between the deflectors;
a prism disposed at the focal position of the first lens between the lenses, a photoelectric element disposed so as to receive a portion of the light beam through the prism, and a light beam reflected from the second deflector. It is characterized by comprising a relay lens arranged to allow light to enter.

The invention will be explained with reference to the drawings.

FIG. 2 shows an example of an optical scanning device according to the present invention, in which elements corresponding to those in FIG. 1 are designated by the same symbols as in FIG. 1.

In this example, the photoelectric element 12 for extracting the synchronizing signal is arranged at a position where the light beam is focused behind the first deflector 2 via a prism 13 as required, that is, at the focal point of the lens 3.

With this arrangement, a portion of each optical beam 14 horizontally deflected by the first deflector 2 is incident on the photoelectric element 12, so that a synchronization signal synchronized with this is obtained.

Therefore, it is sufficient for the lens 6 to have an angle of view that satisfies only the necessary scanning range, and there is no need to make the lens 6 an unnecessarily wide angle of view as in the method of the prior application shown in FIG.

Further, since each horizontal scanning light beam 14 deflected by the deflector 2 is received by the light receiving element 12 via the prism 13 and is always generated at approximately the same position, the light receiving element 12 and the prism 1
3 can be significantly reduced compared to the method of the prior application shown in FIG.

Furthermore, in order to arrange the light receiving element 12 at the focal point of the lens 3,
A synchronization signal with an extremely clean waveform can be obtained, and the first
It is not necessary to provide the lens 10 that focuses the light reflected by the prism 8 onto the light receiving element 11 as in the method of the prior application shown in the figure.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the synchronizing signal extraction method described in Japanese Patent Application No. 49-981,70, and FIG. 2 is a diagram showing an example of the optical scanning device of the present invention. 1...Light source, 2...First deflector, 3,
4... Life-size afocal lens system, 5...
...Second deflector, 7...Scanning plane, 12...
...Photoelectric element, 13...Triangular prism, 14.
...Horizontal scanning light beam.

Claims (1)

[Claims] 1. A first deflector made of a rotating polygon mirror for scanning in a first scanning direction; and a direction perpendicular to the first scanning direction, that is, a second scanning direction, by directing the reflected light from the first deflector to a direction perpendicular to the first scanning direction. a second deflector arranged to scan the direction; a same-magnification afocal lens system in which first and second lenses are arranged from the first deflector side between the first and second deflectors; a prism disposed between the first and second lenses and at a focal position of the first lens; a photoelectric element disposed so as to receive a portion of the light beam through the prism; 2. An optical scanning device characterized by comprising a relay lens arranged so as to input light reflected from two deflectors.