JPS59148010A - Condenser lens - Google Patents

Abstract

PURPOSE:To cut off unnecessary light easily at low cost and to converge only necessary light effectively by providing an optical filter to the center part of a condenser lens. CONSTITUTION:The optical fiber 3 formed of a thin gold vapor-deposited film is provided to the center part of the condenser lens 1. The metallic vapor-deposited film reflects infrared rays, ultraviolet rays, and X rays and allows only visible light to pass through it. Light energy L including infrared or ultraviolet rays is guided into a photoconductor 2, but the focus of infrared rays R is R0 and the focus of ultraviolet is V0, so the diameter of the photoconductor 2 and the position of the photodetection surface 2a of the photoconductor 2 in an optical- axis direction are so set that either the infrared rays nor ultraviolet rays which are converged to the circumference of the lens are guided into the photoconductor 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a condenser lens that reflects and/or absorbs unnecessary light components and cuts them, thereby effectively condensing only the necessary light components.

The present applicant has previously proposed that sunlight be concentrated by a lens or the like, introduced into a light guide, and transmitted through the light guide to any desired location for illumination or other uses. Therefore, when trying to use the sunlight energy transmitted through the light guide as described above as a photosynthetic light source in chlorella cultivation or forced cultivation of plants, it is necessary to The infrared and ultraviolet rays (and X-rays) that are present are harmful to photosynthetic reactions, so it is necessary to cut out these harmful light components. For this purpose, an optical filter can be provided in the optical path and the infrared rays and ultraviolet rays can be cut by the optical filter, but if an optical filter is to be provided, the structure of the optical system path will become more complicated. Currently, there is no optical filter that cuts out infrared rays and ultraviolet rays at the same time, so two types of optical filters are required, making the structure of the optical system increasingly complex. Also, if you try to insert an optical filter in front of or immediately after the lens, you will need an optical filter with the same size area as the lens, and therefore the area of the optical filter will become large. If you try to put it in.

As lenses become smaller, they may be destroyed by condensed heat, or necessary light components may be reflected by the filter 2, resulting in increased optical loss.

The present invention was made in view of the above-mentioned circumstances, and
It is an object of the present invention to provide a condensing lens that can block infrared rays and ultraviolet rays with a particularly simple and inexpensive structure, and that can be used even in a high energy density optical path.

FIG. 1 is a schematic diagram illustrating an embodiment of a condensing lens according to the invention. 3 is an optical filter, and the condensing lens I may be made of any material (quartz, glass, acrylic, etc.) and may have any structure (Fresnel lens, single lens), but in this example In the center thereof, an optical filter 3 made of a thin gold vapor-deposited film is provided. This gold vapor deposited film 3 reflects infrared rays and ultraviolet rays (and It does not reach conductor 2. In that case, it may be possible to apply gold coating to the entire surface of the condenser lens 1, but this is hardly necessary, and if you do so, the area covered with gold will become wider and you will not be able to use gold. The disadvantage is that the amount increases and the cost increases. That is, in the figure, light energy L including infrared rays and ultraviolet rays is focused by a condensing lens 1 and introduced into a light guide 2. At this time, the focus of infrared ray H is RO, and the focus of ultraviolet ray V is RO. are V and o, so the diameter of the light guide 2 and the position of the light receiving surface 2a of the light guide 2 in the optical axis direction are set such that infrared and ultraviolet rays focused by the peripheral parts of these lenses are introduced into the light guide 2. 5f viewing light can be introduced into the light guide 2. Although an embodiment in which sunlight is focused using a condensing lens according to the present invention has been described below, the present invention is not limited to the case where sunlight is focused using a condenser lens according to the present invention. When introducing light from a human light source containing a large amount of infrared and ultraviolet rays, such as a lamp, into the light guide after cutting off the infrared rays and ultraviolet rays, or from any other arbitrary light source by cutting off the infrared rays and/or ultraviolet rays. It will be readily understood that it can also be used when introduced into a light guide.

2 to 5 are diagrams showing other embodiments of the present invention, respectively. In FIG. 2, when a Fresnel lens is considered as the condenser lens 1, gold vapor deposition as described above is deposited on the back side of the condenser lens. FIG. 3 shows an example in which an optical filter 3 made of a film is provided, in which a red light absorption filter 4 and an ultraviolet absorption filter 5 are used as optical filters, and these are connected to the central surface of the condensing lens 1. FIG. 4 shows an example in which an infrared absorption filter 4 and an ultraviolet absorption filter 5 are provided separately in a condensing lens 1.
FIG. 5 shows an example in which an infrared absorbing filter lens 1' is used as the condensing lens, and an ultraviolet absorbing filter 5 is provided on the central surface or rear surface of the lens 1'. shows.

As is clear from the explanation below, according to the unreleased 1st 1st,
With a simple and inexpensive configuration, unnecessary frequency components can be cut off and only essential frequency components can be effectively collected. When using a reflection type optical filter, compared to an absorption type optical filter as shown in Figs.
Because the thermal deterioration of the condensing lens due to infrared and ultraviolet rays is small.

It can be used without significant thermal deterioration even in an optical path with high optical energy density.

[Brief explanation of drawings]

1 to 5 are configuration diagrams for explaining the present invention in detail, respectively. 3, i'... Condensing lens, 2... Light guide, 3...
Infrared and ultraviolet reflection filter, 4... infrared absorption filter, 5... ultraviolet absorption filter.

Claims (1)

[Claims] A condensing lens characterized by having an optical filter in the center.