JPS63244001A - Prism - Google Patents

Abstract

PURPOSE:To improve transmittance of a pentagonal roof prism to laser light by subjecting a part of said prism to dichroic mirror coating and attaching a triangular columnar prism directly to said part. CONSTITUTION:The laser light and visible light reflected by a target passes an objective lens 3 and enters the pentagonal columnar prism 1, transmits the dichroic mirror coated on the triangular columnar prism 2 side by optical paths A B and enters the triangular columnar prism 2. The laser light passes the optical paths B, G in the prism 2 and enters a photodetector 9. The visible light is reflected by the dichroic mirror and is passed through the part having no dichroic mirror by the optical paths A B C D E from which the light enters the prism 2 and enters the eye through the optical paths E F. The reduction of the size over the entire part of the device is thereby reduced and the transmittance of the laser light is increased by about 30%.

Description

[Detailed Description of the Invention] [Industrial Application Field] This FA is a distance measuring device using laser light Iw, which separates a visible light beam for standardizing a target and a received laser beam for distance measurement; and a prism that inverts visible light to obtain an orthogonal image of a target.

[Conventional technology]

Conventionally, as this type of prism, there have been those shown in FIGS. 6 to 12. Fig. 6 shows the optical system of a distance measuring device incorporating a prism, Figs. 7 to 12 show the shapes of each part of the prism, Fig. 1 is a plan view of the roof prism, and Fig. 8 shows the roof prism. 9 is a plan view of a quadrangular prism, FIG. 10 is a side view of a quadrangular prism, FIG. 11 is a plan view of a triangular prism, and FIG. 12 is a side view of a triangular prism.

In Fig. 6, (1) is a roof prism, (2) is a triangular prism, (3 is an objective lens, (4I is a reference reticle, (51 is a contact lens, (6) is an eye, and (7) is a laser beam. A light condensing lens, (81 is a pinhole for limiting the receiving field of view, (9) is a photodetector, (1 (l is a laser beam transmission optical system, a* is a laser oscillator, (13 is a square prism) be.

In Figures 7 and 8, C1) is a roof prism;
In FIG. 9 and FIG. 1a, α3 is a square prism, lI:l is a dichroic mirror coat, and in FIGS. 11 and 8112, (21 is a triangular prism).

Next, the operation will be explained. The laser beam MA emitted from the laser oscillator aυ is adjusted to an appropriate spread angle through the transmitter system in, and is transmitted toward the target to be measured. The transmission optical axis of the transmission optical system is adjusted in advance so that it is parallel to the reference optical axis, which will be described later, so that by setting the target as a reference, the laser beam can be transmitted toward the target. The visible light and laser reflected light from the target pass through the objective lens (31) and enter the roof prism (11).The visible light and laser light that entered the roof prism (1) pass through the optical path A −+ 73−+ Q −+
It enters the square prism 0 via p. square prism 0
What is the visible light that enters 3?

The light passes through the optical path p -+ Jlj -* 'IP, and after being reflected by the dichroic mirror coated on the surface in contact with the triangular prism brocade), it advances to the optical path 31' -p B-+ and passes through the reticle (41 and eyepiece (51). Te, eyes (6,
to go into. The laser light entering the square prism αa follows the optical path D-+E-+IF.

The light passes through the dichroic mirror coated on the surface in contact with the triangular prism (2), enters the triangular prism (2), follows the optical path p −+ 3, and passes through the condenser lens (7) and pinhole (8). Enter the photodetector (9). If you adjust the positional relationship between the reticle +41 and the pinhole (81) in advance so that when the visible light from the target passes through the center of the reticle (4+), the reflected laser beam from the target will pass through the pinhole (81). By aiming the target so that the light can be seen at the center of the reticle +41, the reflected laser '
The light can be received by the photodetector (9).

In addition, the image seen by the eye (6) due to visible light is an inverted image with only the objective lens (3), but the image seen with the roof prism (11
Turn it upside down or upside down on the roof surface of the roof prism (opening) twice,
Since it is reflected three times in the square prism υ, a total of five times, that is, an odd number of times, the left and right sides are also reversed, resulting in an erect image.

[The problem that the invention attempts to solve]

In conventional prisms, visible light and laser light are
Since it comes out at an angle of
There was a drawback that the entire space would be too large to utilize. Also, when the laser beam passes through the prism interior, it is reflected twice (A→B −+ Q and D→E→?) and transmitted through the boundary surface five times (A, D, F, G
:D has a thin air layer and two interfaces. The transmittance is low because of the In particular, the surface containing D is A-+B-+
Since total reflection of C and p-+B→E is performed, a non-reflection coating cannot be applied, and the transmittance cannot be increased to more than 16% per surface.

As an example, the overall transmittance is 85
%, the transmittance of the dichroic mirror is 80 cm, and the reflectance/transmittance of the other reflective/transmissive surfaces is s9-, the total is about 68%. Furthermore, the prism is composed of three parts: a roof prism, a square prism, and a triangular prism.Moreover, the roof prism and the square prism must be placed with a thin air layer in order to allow for total reflection, making it difficult to assemble. there were.

[Means for resolving gaps]

The shape of the quadrangular prism is changed from a quadrangular prism to a pentagonal prism, and a part of the roof prism is covered with a mirror coat, and a triangular prism is attached directly to the roof prism. The light and the laser beam are emitted in the same direction, the transmittance for the laser beam increases to approximately 88%, and the number of components of the prism is reduced to two.

〔Example〕

Hereinafter, an example of a coffin according to the present invention will be explained. FIG. 1 is a diagram showing the optical system of a laser ranging device using a prism according to the present invention, FIG. 2 is a view in the plane of a pentagonal prism, and FIG. 3 is a view from the f1 plane of the pentagonal prism.

FIG. 4 is a plan view of the triangular prism, and FIG. 5 is a side view of the triangular prism.

In Fig. 1, (1) is a pentagonal prism, (2) is a triangular prism, (3I is an objective lens, and (41 is a reticle).

(51 is an eyepiece lens, (6; is an eye, (7) is a laser beam condensing lens, (8) is a pinhole, (9) is a photodetector, (
1α is a laser beam transmission optical system, (112. is a laser oscillator. In Fig. 2, (1) is a pentagonal prism,
α3 is dichroic mirror coat, in Figure 3,
(1) is a pentagonal prism, and in FIGS. 4 and 5, (2) is a triangular prism.

Next, the operation will be explained. The laser light emitted from the laser oscillator aυ, transmitted through the source system αa, and reflected at the target, and the visible light from the target pass through the objective lens (3).
Enters the pentagonal prism (1+).The laser beam that has entered the pentagonal prism (1) passes through the pentagonal prism +11% via the optical path A - + B, and then passes through the pentagonal prism +11 triangular prism +21 Q coated dichroic mirror 2.
It passes through and enters the triangular prism (2). The laser light passes through the triangular prism (2) through optical paths B and G, passes through the 1x lens (7) and the pinhole (81x), and enters the photodetector (9).The visible light that has entered the pentagonal prism is Reflected by the above dichroic mirror, the optical path A-+ passes through the pentagonal prism.
B-+C-4 D→E, enters the triangular prism (2) through the part without the dichroic mirror coat, passes through the triangular prism (2) via the optical path E→F, and enters the reticle (
41. Enters the eye (6:) through the eyepiece lens (51).The laser 11 only passes through one surface (B) of the guichroic mirror in the prism, the angle of incidence (A), and the exit surface (G), which is different from the conventional technology. Assuming the same transmittance as in the example, the transmittance is 88%.

〔Effect of the invention〕

As described above, according to the present invention, since the visible light emitted from the prism and the laser light are parallel to each other, space can be effectively utilized when incorporating an optical system into a distance measuring device, and the entire device can be miniaturized. In addition, the number of reflections of the laser beam in the prism goes from 4 times including 2 times on the roof surface to 0 times, and from 5 transmitting surfaces to 3, the transmittance increases by about 30 degrees. Furthermore, the number of parts constituting the prism is reduced from three to two, and there is no need for an air layer, making assembly easier.

[Brief explanation of drawings]

Figure 1 shows a laser distance measurement v using a prism according to the present invention.
2 is a plan view of a pentagonal prism according to the present invention, FIG. 3 is a side view of the prism, FIG. 4 is a plan view of a triangular prism, FIG. The figure shows an optical system of a laser range finder using a prism according to the prior art, and FIG. 7 is a plan view of a roof prism according to the prior art.
Figure 8 is the same side view, Figure 8 is a plan view of the square prism,
Figure 10 is a side view of the same, Figure 11 is a plan view of the triangular prism, and Figure 12 is a side view of the same. Objective lens, (41 is reticle, (51 is eyepiece, (6) is eye, (7) is laser beam condensing lens. (8) is pinhole, (θ2 is photodetector, an is laser beam transmission optical system, α-J laser oscillator, α2 is a quadrangular prism. Note that the same reference numerals in each figure indicate the same or parallel parts.

Claims (1)

[Claims] The interior angles are 112.5°, 112.5°, and 135°.
, 67.5°, 112.5° of the sides of the scalene pentagonal prism, adjacent to the sides that include the internal angle 112.5° and internal angle 135° horizontal lines, both sides are the internal angle 112.5° horizontal lines. The enclosed side surface is a roof surface with an angle of 90° with a vertical line parallel to the base of the pentagonal prism, and a reflective coating is applied to the roof surface at an internal angle of 67.5° and an internal angle of 112.5°. 112.5 A pentagonal prism with a dichroic mirror coated half on the horizontal line side and an inner angle of 2.
2.5°, 67.5°, 90° triangular prisms,
The side surface of the pentagonal prism that includes the internal angles 67.5° and 112.5° is connected to the side surface that does not include the internal angle of 90° of the triangular prism, and the internal angle 67.5° of the pentagonal prism.
A prism characterized in that the 5° glue line and the 67.5° inner angle glue line of the triangular prism are arranged in close contact so that they are on the same side.