JPH0627401A - Optical scan image information detecting device - Google Patents

Abstract

PURPOSE:To provide a two-dimensional optical scan image information detecting device for correcting a defect of becoming a curve-like scan of a pyramidal mirror, being like energy saving, having a wide view angle, being compact, and generating no image distortion. CONSTITUTION:A light beam 2 emitted from a light source 1 is guided to the reflecting surface 5 of the slant face of a pyramidal mirror 3 by an optical member 9 for changing an optical path such as a prism, etc. The pyramidal mirror 3 has a rotation axis 4 and rotates, and the light beam which is emitted from the optical member 9 and goes to the reflecting surface 5 is also rotatable by synchronizing with the pyramidal mirror 3, and at the time of optical scanning, a reflecting position P on the reflecting surface 5 is roughly fixed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention, by scanning a subject with a light beam and receiving reflected light from the subject,
The present invention relates to an apparatus for detecting a subject image, that is, an optical scanning image information detection apparatus.

[0002]

2. Description of the Related Art A subject image targeted by the present invention is not only information about light and shade but all information obtained by irradiating light. For example, physical / chemical information obtained from absorption / scattering characteristics by the subject,
This includes distance / speed information of the subject, and measurement / recognition of three-dimensional structures.

Conventionally, polygon mirrors, pyramidal mirrors, galvanometer mirrors, holograms, etc. are known as scanners in the main scanning direction used for such two-dimensional scanning. Then, in the case of detecting weak scattered light from a subject image existing in a measurement range having a wide angle of view of 90 ° or more in a short-distance region, a wide angle of view scanning and a wide aperture are required,
A polygon mirror and a pyramidal mirror are suitable, and a pyramidal mirror is superior in terms of compactness.

FIG. 10 is an explanatory view of the function of the pyramidal mirror. In FIG. 10, 1 is a light source, 2 is a light beam, 3 is a pyramidal mirror, 4 is a rotation axis of the pyramidal mirror, 5 is a reflecting surface of the pyramidal mirror, and 6 is a reflecting surface of the light beam 2 when the pyramidal mirror 3 is rotated. The locus of the incident point on 5 and 7 is the reflected light beam.

The light beam 2 emitted from the light source 1 travels in parallel with the rotation axis 4 of the pyramidal mirror 3, and the pyramidal mirror 3
Is incident on the reflection surface 5 of. Pyramid mirror 3 and rotation axis 4
It is known that when it is rotated around, the locus 6 of the incident point of the light beam 2 on the reflecting surface 5 draws a part of a conic curve as illustrated. Therefore, in general, the reflected light beam 7 does not perform linear scanning but performs curved scanning.

[0006]

As described above, the optimum pyramidal mirror as a scanner in the main scanning direction used for two-dimensional scanning has a drawback that the reflected light beam performs a curved scanning. Therefore, from the two-dimensional scanning in combination with the sub-scanning mirror (not shown),
There is a problem that image distortion occurs when two-dimensional image information about a subject is obtained.

The present invention has been made in view of the above circumstances, and an object thereof is to efficiently use energy in an optical scanning image information detecting device using a pyramidal mirror without reducing the intensity of a scanning light beam. Then, it is to obtain two-dimensional image information that has a wide angle of view, is compact, and has no image distortion.

[0008]

An optical scanning image information detecting apparatus of the present invention comprises a light source, and an optical member for guiding a light beam emitted from the light source to a reflecting surface for reflecting the light beam for optical scanning.
By disposing a pyramidal mirror having the reflecting surface on an inclined surface and rotating the light beam emitted from the optical member in synchronization with the pyramidal mirror, the reflection position on the reflecting surface is substantially fixed during optical scanning. It is characterized by

[0009]

1 is an explanatory view of the operation and principle of the optical scanning image information detecting device of the present invention. In FIG. 1, reference numerals 1 to 7 indicate FIG.
The same as 0, but the pyramidal mirror 3 has a vertex cutting portion formed by cutting the vertex. Reference numeral 9 denotes an optical member such as a prism, which is fixed or fixed to the apex cut portion of the pyramidal mirror 3 via a support plate 12, and guides the light beam 2 emitted from the light source 1 to a reflecting surface 5 for reflecting light for scanning. is there. Reference numerals 10 and 11 are reflecting surfaces of the prism 9 that face each other. As will be described later, the presence of the apex excision portion is not an essential requirement.

A light beam 2 emitted from a light source 1 travels along a rotation axis 4 of a pyramidal mirror 3 and enters a prism 9. Then, after being reflected by the reflecting surface 10 and the reflecting surface 11 of the prism 9, it goes out of the prism 9 and is reflected by the reflecting surface 5 on the inclined surface of the pyramidal mirror 3. The prism 9
Since it is fixed to the pyramidal mirror 3, the reflection position P of the light beam on the reflection surface 5 of the pyramidal mirror 3 is always at the same place regardless of the rotation of the pyramidal mirror 3, and the reflected light beam 7 is reflected by the pyramidal mirror 3. With the rotation of, the linear scanning will be performed. Therefore, two-dimensional image information without image distortion can be obtained by two-dimensional scanning in combination with a sub-scanning mirror (not shown).

[0011]

2 to 5 are explanatory views of the first embodiment of the optical scanning image information detecting apparatus of the present invention. 2 is a side view, FIG. 3 is a plan view, and FIGS. 4 and 5 are side views of a prism which is a part of the apparatus. 2 and 3,
Reference numerals 20 and 30 are coupling prisms as optical coupling elements, 40 is a separating prism as a light separating element, 50 is a pyramidal mirror having a vertex cutting section 51 formed by cutting the vertices.
2 is a cavity in which the rotating shaft 54 of the pyramidal mirror 50 concentrically penetrates, 53 is a bearing, 60 is a mirror, 70, 71
Is a lens, and 72 and 73 are light receiving elements. The coupling prisms 20 and 30 as the light coupling elements and the separation prism 40 as the light separation element are optical path changing optical members as described in detail below. That is, these prisms are optical members that guide the light beam emitted from the light source to the reflecting surface that reflects it for optical scanning.

Details of the combining prism 20 are shown in FIG. In FIG. 4, reference numerals 21 and 22 denote light beams, which are two laser semiconductor elements LD1 and L (not shown).
Emitted from D2, the polarization directions differ from each other by 90 °. That is, the light beam 21 is p-polarized and the light beam 22 is s-polarized. Reference numeral 23 is a parallel prism, 24 is a triangular prism, 25 is a quarter-wave plate, 26 is a polarizing film, 23 'is a reflecting surface of the parallel prism 23, and 80 is a light beam emitted from the coupling prism 20.

The light beam 21 from the laser semiconductor device LD1 enters the parallel prism 23, is reflected by the reflecting surface 23 ', passes through the polarizing film 26 and the triangular prism 24, and then,
It is converted into circularly polarized light by the quarter-wave plate 25 and becomes an emitted light beam 80. Similarly, the light beam 22 from the laser semiconductor element LD2 enters the triangular prism 24 and is reflected by the polarizing film 26. Then, it is converted into circularly polarized light by the quarter-wave plate 25, and becomes the emitted light beam 80.

The coupling prism 30 shown in FIG. 2 has the same function as that of the coupling prism 20 described above. That is,
Two laser semiconductor devices LD3 and LD4 (not shown)
The two light beams emitted by the coupling prism 30 and having different polarization directions from each other by 90 ° are emitted by the coupling prism 30.
Connect to 0 '.

The details of the separating prism 40 are shown in FIG.
It is shown in (b). FIG. 5B is a side view of FIG. 5A. In FIGS. 5A and 5B, 41 is a quarter wavelength plate, 42 and 44 are parallel prisms, 43 and 45 are triangular prisms, 46 is a quarter wavelength plate, 47 is a polarizing film, and 48.
Is the same polarizing film, but is in a position rotated by 90 ° with respect to the polarizing film 47.

The circularly polarized light beam 80 incident on the separating prism 40 from above is converted into p-polarized light and s-polarized light by the quarter-wave plate 41. The p-polarized light passes through the polarization film 47, is reflected by the polarization film 48 rotated by 90 ° and the reflection surface 44 ', and becomes a light beam 82 shown in FIG. 5B. The s-polarized light is reflected by the polarizing film 47 and the reflecting surface 42 'to become a light beam 83.

The circularly polarized light beam 80 'which is incident on the separating prism 40 from below is converted into p-polarized light and s-polarized light by the quarter-wave plate 46. p-polarized light is polarizing film 4
8, reflected by the reflecting surface 45 'to become a light beam 85. The s-polarized light passes through the polarizing film 48 and is rotated by 90 °.
7, reflected by the reflecting surface 43 ', and becomes the light beam 84 shown in FIG. From the above description, it can be seen that the circularly polarized light beams 80, 80 ′ incident from the upper and lower sides of the separation prism 40 eventually become four light beams 82, 83, 84 and 85.

2 and 3, the separation prism 40 is fixed or fixed to the apex cutting portion 51 of the pyramidal mirror 50. The pyramidal mirror 50 is provided with a cavity 52 in which a rotating shaft 54 concentrically penetrates and serves as a passage for the light beams 80 and 80 '. Then, a bearing 53 supporting the rotating shaft 54 is provided below the pyramidal mirror 50.
Are fixed or fixed, and the pyramidal mirror 50 is configured to be rotatable with respect to the rotation shaft 54 by a support mechanism and a drive mechanism, both of which are not shown.

As shown in FIGS. 5 (a), 5 (b) and 2, the light beams 83, 84 are reflected by the reflecting surface 50 'of the pyramidal mirror 50 and are horizontal in the direction parallel to the paper surface. It becomes a light beam. Similarly, the light beams 82 and 85 are also reflected by the reflecting surface 50 ′ of the pyramidal mirror 50 and become a horizontal light beam in the direction perpendicular to the paper surface. After all, the separation prism 40
The four light beams 82, 83, 84, and 85 emitted downward from become four horizontal light beams.

As the pyramidal mirror 50 is rotated by a driving mechanism (not shown), these horizontal light beams are
Perform main scanning in the horizontal direction. Further, by a driving mechanism (not shown), the mirror 60 makes a reciprocating rotary motion around the rotary shaft 61 as shown by an arrow 62, and the light beam 86 reflected by the mirror 60 scans in the sub-scanning direction perpendicular to the main scanning. To do. Actually, the light beam 86 performs main scanning in the horizontal direction.
In order to simplify the drawing, the mirror 60 is shown rotated by 90 °.

As is clear from the above description, the four light beams from the four laser semiconductor elements LD1, LD2, LD3 and LD4 correspond to the four horizontal light beams, respectively. The four horizontal light beams are subjected to time-series amplitude modulation by the sine wave pulse shown in FIG. 6 or a rectangular wave pulse (not shown). In this case, 1 corresponding to the main scanning by the pyramidal mirror 50, respectively.
The modulation is applied only in the time interval of / 4 rotation. Further, of scattered light from a subject (not shown), signal components substantially parallel to the light beam 86 for two-dimensional scanning include the mirror 60, the reflecting surface 50 ′ of the pyramidal mirror 50, the lenses 70 and 71.
After that, the light is detected by the light receiving elements 72 and 73 arranged on the axes of the lenses 70 and 71, respectively (see FIG. 3).

In the first embodiment, four semiconductor laser light sources are used in a detection device composed of a pyramidal mirror 50 having four reflecting surfaces, coupling prisms 20 and 30, a separating prism 40, a mirror 60 and the like. The horizontal light beam thus obtained is time-sequentially modulated as shown in FIG. 6 to enable two-dimensional scanning with high energy utilization efficiency by a high-speed and strong scanning light beam. Although shown, it can be easily changed even when the number of semiconductor laser light sources or the number of reflecting surfaces of the pyramidal mirror is small.

For example, when the number of reflecting surfaces of the pyramidal mirror is two, the separating prism may be partially changed as shown in FIG. In FIG. 7, 91 is a quarter-wave plate, 96 and 97 are parallel prisms, 92 and 95 are triangular prisms, 94 is a half-wave plate, and 93 and 98 are polarizing films. Then, the circularly polarized light beam 80 incident from above on the partially changed separation prism 90 is converted into the quarter-wave plate 9
1, the light is converted into p-polarized light and s-polarized light. The p-polarized light passes through the polarizing film 93, passes through the triangular prism 92, is converted into s-polarized light by the half-wave plate 94, and is reflected by the polarizing film 98 and the reflecting surface 96 ′ of the parallel prism 96 to become a light beam 84. . The s-polarized light converted by the quarter-wave plate 91 is reflected by the polarizing film 93 and the reflecting surface 97 'to become the light beam 83.

When the number of reflecting surfaces of the above-mentioned pyramidal mirror is two, the cavity 52 and the coupling prisms 20 and 30 are provided.
One of them (for example, the coupling prism 30) becomes unnecessary. Further, instead of the lenses 70 and 71, FIGS.
1 lens 101, 1 light receiving element 102 shown in FIG. 1, or a Fresnel lens 103 equivalent thereto and a light receiving element 1
02 can be used. In this case, the light receiving element 1
It is sufficient to provide one 02 on the rotating shaft 54, and there is an advantage that the loss of the amount of signal light is smaller than the configuration in which the two lenses 70 and 71 are arranged. Further, the polarization separation by the polarizing film can be replaced with the polarization separation by the polarization beam splitter using calcite.

9 (a), 9 (b) and 9 (c) are explanatory views of the light separating element in the second embodiment of the optical scanning image information detecting apparatus of the present invention. 9A shows the configuration and the optical path of the light separation element 109, and FIG. 9B is a side view of FIG. 9A. In FIG. 9A, 110 and 116 are quarter wavelength plates, 111 and 113 are parallel prisms, 112 is a polarizing film, 114 is a triangular prism, 115 is a polarizing prism, and 8
0,80 'is a light beam incident along the rotation axis 120,
Reference numerals 82 and 84 are horizontal light beams. Also, FIG. 9 (b)
117 is a polarizing film, and 83 and 85 are horizontal light beams.
Reference numeral 118 in (c) is a polarizing film.

The circularly polarized light beam 80 incident on the light separating element 109 from above is converted into p-polarized light and s-polarized light by the quarter-wave plate 110. The p-polarized light passes through the polarizing film 112 and the triangular prism 114, is reflected by the polarizing film 117 of the polarizing prism 115, and becomes a horizontal light beam 83. Also,
The s-polarized light is the polarizing film 112 and the reflecting surface 1 of the parallel prism 111.
A horizontal light beam 8 reflected by 11 'and the reflecting surface 111 "
It becomes 2. The circularly polarized light beam 80 ′ incident on the light separating element 109 from below is converted into p-polarized light and s-polarized light by the quarter-wave plate 116. p-polarized light is polarized prism 11
It is reflected by the polarizing film 117 of No. 5 and becomes a horizontal light beam 85. The s-polarized light passes through the polarizing prism 115 and is reflected by the polarizing film 112 and the reflecting surfaces 113 ′ and 113 ″ of the parallel prism 113 to become a horizontal light beam 84.

After all, the light separating element 109 has the rotation center axis 1
Light beams 80, 80 'incident from above and below along 20
Is converted into four horizontal light beams 82, 83, 84 and 85. Then, by rotating the light separation element 109 around the rotation center axis 120, it can be seen that a subject (not shown) can be scanned by four horizontal light beams orthogonal to each other. In the above case, the scattered light from the subject is detected by a light detection system (not shown) installed separately from the light separation element, for example, the light detection system using the pyramidal mirror described in the first embodiment.

In FIG. 9C, the light beams 80 and 80 'are divided into two beams.
The light beam is converted into a horizontal light beam 82, 84 of the book, and its action can be understood from the description of FIGS. 9 (a) and 9 (b). The feature of the present embodiment is that it shows the case where scanning can be performed by the light separating element alone, and that the light separating element and the pyramidal mirror do not necessarily have to be integrally combined.

In any of the above-described embodiments, a laser light source is used as a light source, and the light beams emitted from the light source are laser lights having polarization directions different from each other by 90 °, and the light is separated according to the polarization direction. However, the light source and the light beam used in the optical scanning image information detecting device of the present invention are not limited to these. For example, the light beam emitted from the light source may be separated by a half mirror and used.

In the first embodiment described above, the apex of the pyramidal mirror is cut off. This is a desirable configuration because it facilitates fixing of the optical member that guides the light beam from the light source to the reflecting surface. However, in the optical scanning image information detection device of the present invention, the light beam incident on the pyramidal mirror may be provided so as to be rotatable in synchronization with the rotation of the pyramidal mirror, and the apex of the pyramidal mirror may be cut off. Is not a mandatory requirement. Further, fixing the optical member and the pyramidal mirror is a preferable mechanism that realizes the above synchronization most easily. However, even if the mechanism is such that the optical member and the pyramidal mirror are separated and each has a different driving means, there is no problem if the rotation cycles are synchronized.

[0031]

As described above, the optical scanning image information detecting apparatus of the present invention is capable of efficient energy utilization without reduction of the intensity of the scanning light beam, wide field angle, compact two-dimensional scanning without image distortion. to enable.

[Brief description of drawings]

FIG. 1 is a side view for explaining the operation and principle of an optical scanning image information detecting device of the present invention.

FIG. 2 is a first diagram of the optical scanning image information detection device of the present invention.
It is a side view of an Example.

FIG. 3 is a first diagram of the optical scanning image information detection device of the present invention.
It is a top view of an example.

FIG. 4 is a functional explanatory diagram of a coupling prism that is an optical path changing optical member of the first embodiment.

FIG. 5 is a functional explanatory diagram of a separation prism which is an optical path changing optical member of the first embodiment.

FIG. 6 is an explanatory diagram of modulation by pulses of a horizontal light beam in the first embodiment.

FIG. 7 is a functional explanatory view of a separation prism partly modified with the optical member of the first embodiment.

FIG. 8 is an explanatory diagram of an arrangement of a lens and a light receiving element, which are components of the first embodiment.

FIG. 9 is a second view of the optical scanning image information detection device of the present invention.
It is a functional explanatory view of the light separation element of an example.

FIG. 10 is an explanatory diagram of a function of a pyramidal mirror.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source 2 Light beam 3 Pyramid mirror 4 Rotation axis 5 Sloping reflection surface of pyramidal mirror 9 Prism as optical path changing optical member

Claims (1)

[Claims] 1. An optical member comprising: a light source; an optical member for guiding a light beam emitted from the light source to a reflection surface for reflecting the light beam for scanning; and a pyramidal mirror having the reflection surface on an inclined surface. An optical scanning image information detecting device characterized in that the reflection position on the reflecting surface is almost fixed at the time of optical scanning by rotating the light beam emitted from the above in synchronization with the pyramidal mirror.