Optoelectronic component arrangement

Details Optoelectronic component arrangement Optoelectronic component arrangement

1999-03-08

2001-11-20

Evans, F. L. (Department: 2877)

Radiant energy

Photocells; circuits and apparatus

Photocell controlled circuit

C250S2140LS, C257S431000

Reexamination Certificate

active

06320178

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to an optoelectronic component arrangement which includes a radiation-sensitive detector element arranged on a carrier substrate.
BACKGROUND INFORMATION
U.S. Pat. No. 5,670,781 discloses arranging, for example in the scanning unit of an optical position measuring device, a radiation-sensitive, optoelectronic detector element on a glass carrier substrate using so-called “flip-chip” or “chip-on-glass” technology. This provides certain advantages, particularly with respect to the contacting of the detector element, since one can eliminate the need, for instance, for filigreed bonding wires, which are otherwise required for the contacting.
So-called CMOS photoelements, for instance, are considered as suitable detector elements for an arrangement of this kind. These types of photoelements exhibit certain properties which have proven to be disadvantageous in high-precision measuring system applications. The publication, “Image Sensing With Maximum Sensitivity Using Industrial CMOS Technology” by P. Seitz in SPIE vol. 3099, 1997; pp. 22-33, discloses, for example, that the sensitivity of CMOS photoelements depends substantially on the detected radiation wavelength and the CMOS photoelements exhibit wavelength-dependent oscillations. A graphic representation of this relation is shown in
FIG. 1
, which illustrates the detected radiation intensity as a function of the radiation wavelength when working with components of this kind. In the measuring operation of a scanning unit of an optical positional measuring system, it cannot always be avoided that the particular light source being used has a fluctuating emitted radiation wavelength. Besides the bandwidth or half-value width FWHM
LQ
of the light source being used,
FIG. 1
also indicates the fluctuation range &Dgr;&lgr;
LQ
of the emitted wavelength of this light source. Fluctuations of this kind in the emitted wavelength &lgr;
LQ
of the light source are attributed, for example, to temperature variations. Accordingly, the result is an insufficiently stable response characteristic in an optoelectronic detector element of this kind that is especially not stable enough in the case of a detection wavelength that may vary as a function of temperature.
U.S. Pat. No. 5,483,060 discloses arranging a CMOS detector element using “flip-chip” technology on a glass carrier substrate. However, in the depicted arrangement, the problems discussed above likewise arise with respect to the wavelength-dependent response characteristic of these detector elements.
In conjunction with the arrangement of optoelectronic components on a glass carrier substrate, reference is also made to U.S. Pat. No. 5,682,066. This patent discloses arranging a special filling material between an LED and the glass carrier substrate. A filling material is selected whose constituents have refractive indices identical to those of the carrier substrate. however, merely selecting a filling material of this kind does not solve the problems addressed above when a CMOS photoelement is to be arranged on a carrier substrate.
SUMMARY OF THE INVENTION
An object of the present invention is, therefore, to devise an optoelectronic component arrangement that is particularly suited for a scanning unit of an optical position measuring device, which will enable a radiation-sensitive detector element to be easily arranged on a carrier substrate, without entailing substantial contacting complexity, and, at the same time, while ensuring a substantially wavelength-independent response characteristic of the detector element.
The present invention provides an optoelectronic component arrangement comprised of a radiation-sensitive detector element (
1
) having a semiconductor base substrate (
1
.
2
), into which one or more doped partial regions (
1
.
3
) are introduced and having at least one partial layer (
1
.
1
), which is arranged to adjoin the semiconductor base substrate (
1
.
2
). The detector element (
1
) is arranged on a transparent carrier substrate (
2
), and a filling material (
7
) is arranged between the carrier substrate (
2
) and the surface (
3
) of the detector element (
1
) facing the carrier substrate (
2
). All materials, which, in the direction of the carrier substrate (
2
), are arranged in front of the semiconductor base substrate (
1
.
2
) and the doped partial regions (
1
.
3
), have an essentially similar index of refraction (n).
Advantageous specific embodiments of the optoelectronic component arrangement according to the present invention include that: (a) the filling material (
7
), as well as the material of the carrier substrate (
2
), have an index of refraction (n), which is essentially similar to the index of refraction (n) of that partial layer (
1
.
1
), which is arranged to directly adjoin the semiconductor base substrate (
1
.
2
); (b) the detector element (
1
) in front of the semiconductor base substrate (
1
.
2
) has merely a partial layer (
1
.
1
) or a layer system of silicon dioxide, to which both the index of refraction (n) of the filling material (
7
) as well as of the carrier substrate (
2
) are adapted; (c) the detector element (
1
) is designed as a CMOS photoelement; (d) the detector clement (
1
) is applied to the carrier substrate (
2
) using flip-chip contacting technology; (e) the carrier substrate (
2
) is made of glass; and/or (f) the index of refraction (n) is between 1.45 and 1.55.
The present invention also provides a use of an optoelectronic component arrangement of the present invention in the scanning unit of an optical position measuring device.
The various measures of the present invention ensure that the response characteristic of optoelectronic detector elements, as well, such as of CMOS photoelements, is clearly less dependent on wavelength than in disclosed methods heretofore. This means, in turn, that component arrangements according to the present invention can also be used in scanning units of optical position measuring devices, even when it is not always ensured that the wavelength emitted by the radiation source in question remains stable.
Additional advantages of the optoelectronic component arrangement according to the present invention are evident in the simple assembly required for component arrangements of this kind; thus, the detector elements provided can be arranged on carrier substrates using the known “flip-chip” technology. In this context, the contacting of the detector elements can take place, for example, via so-called “metal bumps” or “solder bumps”, or by using a suitable adhesive-type contacting. This enables one, in particular, to avoid expensive contacts using filigreed bonding wires.
Besides the benefit of simple contacts, one achieves the advantage of being able to have an extremely compact design for these kinds of component arrangements; in applications in scanning units of optical position measuring devices, one can realize extremely small dimensions for measuring systems of this kind.


REFERENCES:
patent: 5405809 (1995-04-01), Nakamura et al.
patent: 5483060 (1996-01-01), Sugiura et al.
patent: 5670781 (1997-09-01), Setbacken
patent: 5682066 (1997-10-01), Gamota et al.
patent: 35 12 958 (1985-11-01), None
patent: 43 27 133 (1995-02-01), None
patent: 197 52 511 (1998-06-01), None
patent: 0 502 340 (1992-09-01), None
patent: 0 681 334 (1995-11-01), None
patent: 0 734 074 (1996-09-01), None
P. Seitz, “Image Sensing With Maximum Sensitivity Using Industrial CMOS Technology,” SPIE, vol. 3099, 1997, pp. 22-33.

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