DE4243421A1 - Opto-electronic component for measuring limited region of ultraviolet radiation - contains fluorescent medium stimulated by ultraviolet, optical and filtering arrangement ensuring narrow spectral stimulation region - Google Patents

Abstract

The arrangement converts energy intensive narrow wavelength regions of ultraviolet light into electrical signals. A fluorescent medium stimulated by the ultraviolet light forms an edge filter. Its absorption edge forms the right side of the fluorescence stimulation spectrum. The right edge of the optical medium is processed to ensure optimal total internal reflection. The left edge of the component's sensitivity graph is produced by a primary filter above the fluorescent medium. USE/ADVANTAGE - Esp. for measurement, medical and environmental use. The arrangement enables narrowing of the stimulation spectrum regions to enable yet narrower regions of the wavelength spectrum to be detected.

Description

For the detection of certain Wavelength ranges of the Light is known to Semiconductor photo receiver light about great Wavelength ranges, mostly up to in the infrared range, can detect. Often a certain wavelength highlighted where the Component a special one Has sensitivity. In all other It has wavelength ranges however also one remarkable sensitivity. For example, blue or ultraviolet sensitive Components whose Sensitivity maxima in the Proximity of the infrared range lie.

For most, and those of Application according to the invention, however the great turns Bandwidth as a lack.

The goal is to cover this range to reduce.

Within the Converter component leaves this however not arbitrarily constrict.

With regard to the Color selectivity different possibilities offered. Here are the PN transitions on the Surface of V-trenches, in buried layers and very just below the surface (GB 20 34 971). By downsizing the epitaxial layer thickness the infrared sensitivity limited (DE-OS 25 29 978; DE-AS 25 12 327).

To even lower bandwidths to reach, you take up optical filters, Filter glass combinations and Overlay one or several anti-reflective layers back (up to 9 layers) (DE-OS 30 12 523; GB 15 90 865).

The possibilities of Bandwidth reduction are but with very high cost and production effort connected.

An inexpensive way only detect the UV areas to be able to do that too Invention is based, is simple photosensitive Semiconductor components with Fluorescent materials so too couple that for example short-wave electromagnetic Radiation in longer-wave electromagnetic radiation for which the Semiconductor detector sensitive is.

This is known at Detection of gamma, X-ray and Ultraviolet radiation (EP 03 33 424; EP 03 24 944; EP 02 90 167).

The in claim 1 specified invention is the Problem underlying the area of the luminescence excitation spectrum further narrow around even narrower Wavelength ranges of the UV spectrum detect to can.

This problem is said to Claim 1 thereby solved that one by UV excitation fluorescent Medium properties of a Has edge filter that Absorption edge the excitation to fluorescence in the spectrum limited and thereby the right one Increase in Sensor sensitivity is dimensioned.

The achieved with the invention There are particular advantages in that by a simple  Filter glass arrangement with a Fluorescent medium and one Semiconductor photocell, cheap in a light-tight housing housed, a inexpensive photoelectric device for measuring intensities narrower ultraviolet Wavelength ranges, available is.

An advantageous embodiment the invention is in Claim 5 specified.

Continuing education after Claim 5-11 allows installation in simple Measuring devices for the determination of Intensities and Dose rates one dimensioned Wavelength range in Environment, biology, medicine, Measurement technology and others Areas.

An exemplary embodiment is supported by Fig. 1 so that a highly light-tight housing with a low temperature coefficient according to claim 5 as a holder for an optical filter glass 1 ( Fig. 1) (UV-transparent), an optical edge filter 2 ( Fig. 1) serves as a medium with a luminescent property, a secondary filter medium 3 ( Fig. 1) (fluorescent light permeable) and a holder 4 ( Fig. 1) for an optoelectronic semiconductor component with a corresponding element.
The optical filter glass 1 ( Fig. 1) is arranged under a light entry window of the housing so that only the light that completely traverses the filter reaches the inside of the housing.
The side edges are covered in a light-tight manner so that obliquely incident light cannot pass through a thinner filter and in this way reaches the inside of the housing.
Under the optical filter glass 1 ( Fig. 1), the optical medium 2 ( Fig. 1) is arranged so that all the light reaching the interior of the housing passes through it, ie partially absorbed or converted by luminescence, and the light passing through from a black layer is completely absorbed.
The fluorescent medium has the property of an edge filter according to claim 1 in such a way that its fluorescence excitation spectrum is limited by a spectral absorption edge. It is favorable that the absorption is not caused by conversion to heat, but largely by luminescent light conversion.

In the fluorescent medium, luminescence is excited by electromagnetic radiation in such a way that photons collide with luminescent particles, excite them to luminescence, and the resulting light is emitted evenly distributed in all directions.
In its subsequent migration, the light emitted evenly distributed in all directions encounters strong refractive index transitions at which light refraction or reflection and total reflection occur.

The medium is machined on all its edges so that the cheapest total internal reflection is possible.
As a result of many fluorescent emission radiation, there is a light collection effect 90 degrees to the direction of light incidence along the thickness of the medium.
With a light coupling medium, the medium is connected to another optical medium 3 ( Fig. 1), which filters out the part of the light that is not converted by fluorescence but scattered to the side by the smallest surface irregularities, foreign particles or bubbles in the medium 2 ( Fig. 1) becomes.
As a result, the medium 3 ( Fig. 1) only conducts fluorescence emission light onto a semiconductor photo receiver housed in a housing part for conversion into an electrical signal.

Claims (10)

1. Optoelectronic component for converting energy intensities of narrow wavelength ranges of ultraviolet light into electrical signals, in particular for measurement technology, medicine and the environment, characterized in that the right increase in the spectral photosensitivity of the component is generated by a fluorescent medium when excited by ultraviolet light Edge filter is and its absorption edge determines the right side of the fluorescence excitation spectrum. 2. Optoelectronic component according to claim 1, characterized, that the side edges of the optical medium processed in this way are that the optimal Total reflection inside is guaranteed. 3. Optoelectronic component according to claims 1-2, characterized, that the left rise in Sensitivity curve of the Component by one Primary filter above the fluorescent medium is produced. 4. Optoelectronic component according to claims 1-3, characterized, that an optoelectronic Semiconductor device emitted Fluorescence radiation through a secondary filter directly the light exit surface of the fluorescent medium receives and into one converts electrical signal. 5. Optoelectronic component according to claims 1-4, characterized, that a high light density Housing arrangement the Primary filter, that fluorescent medium, a Secondary filter and that optoelectronic Semiconductor device like this picks up only light a light entry window Primary filter traverses and into the fluorescent medium to stimulate Fluorescent light directed and the fluorescent emission light through total reflection by 90 degrees from the direction of light entry along the thickness of the Fluorescent medium through a Secondary filter on that optoelectronic Semiconductor component for Conversion to an electrical one Signal is brought. 6. Optoelectronic component according to claim 5, characterized, that the housing arrangement from there is light-proof material. 7. Optoelectronic component according to claim 5-6, characterized,  that spacer between the Primary filter, the optical Medium and the bottom plate like that are appropriate that the optimal total reflection is guaranteed. 8. Optoelectronic component according to claims 1-7, characterized, that the optical medium with the Secondary filter and the optoelectronic Semiconductor device through a Light coupling means connected are to minimize losses when To enable light transport. 9. Optoelectronic component according to claims 1-8, characterized, that in the housing arrangement Absorption walls so attached are that stray light absorbed, or obliquely incident light not one Pass thinner filter can. 10. Optoelectronic Component after Claims 1-9, characterized, that the optoelectronic Semiconductor device so in one Housing part are glued can that extraneous light not from a back is detected can be.