JPH0534510A - Composite optical lens and beam splitter using same - Google Patents

Abstract

PURPOSE:To obtain the composite optical lens which can be manufactured easily by forming a shape obtained by combining plural pieces of convex lenses, and also, can obtain plural image forming focuses without using separately a convex lens. CONSTITUTION:A composite optical lens 1 consists of a shape formed by cutting out each one side part of a convex lens 1a and a convex lens 1b whose focal lengths are equal, and joining its cut-out faces to each other. The cut-out faces of the convex lenses 1a, 1b become angle of 45 deg. to a lens center line (a). The joint surface 2 of the composite optical lens 1 is placed so as to become parallel to parallel incident rays 3, the inflextion surface is turned to the incident side of the incident ray 3, and also, an inflextion point is placed in the center of the incident ray 3. In such a way, the parallel incident rays 3 are allowed to form an image in focuses (b), (c) in two parts by passing through the composite optical lens 1. Beam energy in each focus thereof (b), (c) becomes 1/2 of incident energy of the incident ray 3, and a 1/2 split beam is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compound optical lens for splitting a single parallel beam light into a plurality of beams and a beam splitter using the compound optical lens.

[0002]

2. Description of the Related Art As a conventional compound optical lens, Japanese Patent Laid-Open No.
The one disclosed in Japanese Patent Publication No. 235289 is known.
In this conventional device, a plurality of aspherical lenses are combined to form a plurality of parallel lights, and the parallel lights are imaged at a plurality of focal points by a convex lens. Further, in the conventional beam splitter, for example, in the one disclosed in JP-A-1-235289, the beam light passes through at least three lenses.

[0003]

In the above-mentioned conventional composite optical lens, the aspherical lens is complicated to manufacture because of the combination of a plurality of aspherical lenses. There is a problem that a convex lens for image formation is needed for an image, and the number of parts increases. Further, in the conventional beam splitter, in order to generate a plurality of parallel light beams from a single parallel light beam as described above, at least three lenses have to be passed through, so light loss due to lens passing is avoided. Therefore, there is a problem that energy cannot be effectively used.

The present invention has been conceived in view of the above, and a first object thereof is a composite optical system which can be easily manufactured and can obtain a plurality of image forming focal points without separately using a convex lens. A second object of the present invention is to provide a lens, and a second object of the present invention is to provide a beam splitter that requires a minimum number of lenses for beam splitting and can minimize light loss due to passing through the lens.

[0005]

In order to achieve the above object, in a compound optical lens according to the present invention, a plurality of convex lenses having the same focal length are tilted at an angle of 45 ° with respect to each lens center line a. The surfaces are joined to each other. A beam splitter using the compound optical lens according to the present invention has a configuration in which a convex lens is arranged behind the focal position of the compound optical lens.

[0006]

[Operation] In the above-mentioned compound optical lens, when parallel incident light is incident from the curved surface side around the inflection portion, it is imaged at a plurality of focal points by passing through the compound optical lens. Further, in the beam splitter, behind the compound optical lens, it is divided into a plurality of parallel lights by a convex lens.

[0007]

EXAMPLES Examples of the present invention will be described with reference to the drawings. In the figure, 1 is a compound optical lens according to the present invention, and this compound optical lens 1 is a first convex lens 1 having an equal focal length.
a and the second convex lens 1b are cut into the same shape on one side, and the cut surfaces are joined together. The cut-off surfaces of the biconvex lenses 1a and 1b are 45 ° with respect to the lens center line a,
Therefore, the lens center lines a and a of the cemented biconvex lenses 1a and 1b have a shape intersecting at 90 °.
Are joined.

The composite optical lens 1 having the above structure is arranged such that the cemented surface 2 thereof is parallel to the parallel incident light 3.
Moreover, the curved surface is directed to the incident side of the parallel incident light 3, and the inflection point is arranged at the center of the parallel incident light 3. Thus, the focal points b and c parallel to the incident light are formed at the focal points of the respective convex lenses 1a and 1b. Therefore, the parallel incident light 3 passes through the compound optical lens 1 to form an image at two focal positions.

In the above embodiment, the composite optical lens 1 can be manufactured by integral molding. The number of convex lenses 1a and 1b constituting this is not limited to two, but two
It is also possible to combine more than one convex lens, and in this case, focal points are imaged on the exit side by the number of convex lenses.

Further, in the above embodiment, assuming that the parallel incident light 3 is incident from the curved surface side of the bifocal compound optical lens 1 around the inflection portion, the respective convex lenses 1a and 1b constituting the compound optical lens 1 are assumed. ½ of the light beams will be incident on each. At this time, 1 / due to the nature of the convex lens
In the case of the light 2 as well, the respective convex lenses 1a and 1b form one focal point, and the image forming shape at this focal point becomes a circular beam as shown in FIG. The beam energy at each focus is 1/2 of the incident energy of the incident parallel light.
Therefore, a beam divided into ½ is completed. Here, as shown in FIG. 2, when the convex lens 4 is arranged behind the focal position of the compound optical lens 1, the light condensed by this is converted into parallel light by the convex lens 4, whereby the incident parallel light 3 Is split into two parallel lights 3a and 3b.

[0011]

According to the composite optical lens of the present invention,
By using a shape in which a plurality of convex lenses are combined, it can be easily manufactured, and a plurality of image forming focal points can be obtained without using a separate convex lens. Further, according to the beam splitter using the above-mentioned compound optical lens, the number of lenses required for beam splitting can be minimized, and the light loss due to passing through the lens can be minimized.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration and an action showing an example of a compound optical lens.

FIG. 2 is an explanatory diagram showing a configuration and an action showing an example of a beam splitter using a compound optical lens.

FIG. 3 is an explanatory diagram showing a focus image formed by a compound optical lens.

[Explanation of symbols]

1 compound optical lens, 1a, 1b 1st, 2nd convex lens, 2 cemented surface, 3 incident parallel light, 4 convex lens.

Claims (2)

[Claims] 1. A plurality of convex lenses having the same focal length,
A compound optical lens having a shape in which they are joined to each other at an inclined surface inclined at 45 ° with respect to each lens center line a. 2. A beam splitter using a compound optical lens, characterized in that a convex lens is arranged behind the focal position of the compound optical lens according to claim 1.