JPS63252485A - Photosensor unit - Google Patents

Abstract

PURPOSE:To miniaturize a photosensor unit, and to improve accuracy thereof by arranging the device of an optoelectric transducer not packaged onto a substrate, coating a window section for the optoelectric transducer with a transparent package material and coating others with a baked insulating material. CONSTITUTION:A conductor 22 is formed onto a substrate 21 through milk screen printing, and resistance paste is printed, thus shaping a thick-film printed substrate. A chip component 24 such as a transistor, a capacitor, etc., are soldered 25 onto the surface of the substrate 21. A signal processing circuit on the substrate 21 consists of operational amplifiers 27, 28, fixed resistors 29, 30, etc., besides a photodetector 9. Mounting is completed, and the substrate 21 is packaged. An insulating resin is used for packaging, and a light-receiving window section 9a for the photodetector 9 is coated with a transparent resin 34 and other sections with the same transparent resin or an opaque insulating resin 35.

Description

TECHNICAL FIELD The present invention relates to an optical sensor unit, and more particularly to an optical sensor unit in which an optical sensor such as a phototransistor is integrated with a signal processing circuit.

(Prior Art) Conventionally, optical sensor units such as those shown in FIGS. 4 to 7 have been known that integrate a photoelectric conversion element such as a phototransistor and an input/output signal processing circuit.

Figure 4 shows the appearance of an optical sensor unit that integrates a light emitting element and a light receiving element together with a signal processing circuit.
(a) is a front view, (b) is a bottom view, and (C) is a cross section taken along line A. The optical sensor unit has a substantially U-shape, and a light emitting element and a light receiving element are disposed facing each other on the opposing wall 1.2.
Five terminals 3.4° 5.6.7 are protruding from the bottom. The surface of the optical sensor unit is coated with an insulating material, and although not shown, only the light-emitting and light-receiving windows of the light-emitting element and the light-receiving element are covered with a transparent resin material.

FIG. 5 shows the internal configuration of the optical sensor unit, in which seven nodes of the light emitting element 8 are connected to the terminal 3, the cathode is connected to the terminal 4, and the light receiving element 9 is connected to the amplifier 10. A signal processing circuit 13 consisting of a constant voltage circuit 11, a transistor 12, etc.
via terminal 5 (Vcc), terminal 6 (VO), terminal 7
(GND).

The optical sensor unit has a signal processing circuit 13 monolithically integrated with a light receiving element 9 on one chip, a light emitting element 8 facing the light receiving element 9, and pixel elements 8, 9.
Since it detects objects passing through the sensor, it has the characteristics of a large output current and improved noise resistance, but it is a transmission type and its use is limited to digital detection of the presence or absence of an object. Furthermore, since it has a monolithic structure, it is convenient for mass production, but there are many restrictions and it is not suitable for class A and small volume production, where circuit constants and other parts are changed.

Figure 6 shows the external appearance of a transmitted diffused light sensor unit that uses hybrid thick film (hybrid) technology in the amplifier section of the signal processing circuit, (a) is a front view, (b) is a bottom view, and (C) is a front view.
is a side view, and (d) is a top view.

This optical sensor unit has a facing portion 14 that protrudes from the top surface.
A signal processing circuit board (not shown) made of a hybrid thick film is housed in a case 16 having a casing 15, a light emitting element 8 and a light receiving element 9 are respectively disposed in the opposing parts, and four terminals 17 are provided outside the case 16. ~20'i is installed, and has a circuit configuration as shown in FIG. The amplifier section of the <S number processing circuit 13 is a hybrid, but the senna section is a discrete component. Therefore, compared to monolithic structures, there are fewer restrictions when making partial changes, but miniaturization is insufficient.

(Objective) The present invention has been made in view of the above points, and an object of the present invention is to provide a small, highly accurate, highly reliable, and inexpensive optical sensor unit.

(Structure) In order to achieve the above object, the present invention disposes an unpackaged photoelectric conversion element device on a substrate made of ceramic, glass, etc. on which resistors, conductors, etc. of a signal processing circuit are printed, and at least It is characterized in that the light receiving window of the charge conversion element is covered with a transparent packaging material, and the rest of the board is covered with a fired insulating material.

Embodiments of the present invention will be described below based on FIGS. 1 to 3.

Figure 1 is a front view of the optical sensor unit before resin coating, Figure 2
The figure is a top view of the optical sensor unit, and FIG. 3 is an internal circuit configuration diagram.

A conductor 22 is formed by milk screen printing on a substrate 21 made of ceramic or glass, and a resistor 23 is formed by printing a resistor paste in the same manner to form a thick film printed substrate. On the surface of this substrate 21, chip components 24 such as transistors, operational amplifier ICs, capacitors, etc. are bonded with cream solder, and solder 25 is applied using a reflow one-way method. At this time, the light-receiving element 9 such as a photodiode or phototransistor is glued onto the substrate 21 as a device-shaped chip,
Lead wire 26 is connected to conductor 22 by bonding.

As shown in FIG. 3, the signal processing circuit configuration on the substrate 21 includes, in addition to the light receiving element 9, an operational amplifier 27, 28, a fixed resistor 29,
30. It consists of a variable resistor 31, capacitors 32, 33, etc., and when adjusting the amplification degree of the amplifier circuit, the variable resistor 31 is used.
It is possible to attach it externally, but usually a printed resistor 31 is used.
'e) Fine adjustment can be made by IJ mixing.

After the above-mentioned mounting is completed, the mounting board 21 shown in FIG. 1 is packaged for moisture-proofing, dust removal, and other purposes. Fragment 2
The figure shows a packaged optical sensor unit,
An electrically insulating resin is used for the package, and the light receiving window 9a of the light receiving element 9 is covered with a transparent resin 34, and the other parts are covered with a similar transparent resin or an opaque insulating resin 35.

Incidentally, if necessary, the transparent resin of the light receiving window portion 9a can be formed as a convex lens.

The packaging operation is carried out by suspending fine powder of an epoxy packaging material in a firing furnace, placing the substrate 21 therein, and attaching the floating packaging material while heating. If only the light-receiving window portion 9a is made of transparent resin or shaped into a lens, this is done by pouring or the like in a separate process.

In the above embodiment, since only a small current (on the order of nA to μA) is generated in the light receiving element 9 alone, routing the wiring poses a problem in terms of noise resistance. The noise resistance can be improved by using a FET input type operational amplifier in the impedance conversion section or by providing a guard ring in the input section.

(Effects) As described above, the present invention arranges an unpackaged photoelectric conversion element device on a substrate made of ceramic, glass, etc. on which resistors, conductors, etc. of a signal processing circuit are printed, and at least a photo-IIcK conversion element. The light-receiving window is covered with a transparent packaging material, and the rest of the board is covered with a fired insulating material, so it can be produced in relatively small quantities and can easily accommodate changes for improvement. Moreover, it becomes possible to manufacture a small, highly accurate, and highly reliable optical sensor unit at low cost. Furthermore, if a reflective optical sensor unit is used, in addition to digital information such as detecting the presence or absence of an object, analog information can also be obtained from changes in the light receiving lid.

[Brief explanation of the drawing]

Figure 1 is a front view of the optical sensor unit before packaging in the embodiment of the present invention, Figure 2 is a top view of the optical sensor unit after packaging, Figure 3 is an internal circuit configuration diagram, and Figure 4 is a conventional optical sensor. The outline of the unit is shown, (a) is a front view;
(b) is a bottom view, (C) is a side sectional view, (d) is a top view, FIG. 5 is an internal circuit configuration diagram of the conventional example of FIG. 4, and FIG. 6 is of another conventional optical sensor unit. The general appearance is shown, (a) is a front view, (b) is a bottom view, (C) is a side view, (d) is a top view, and FIG. 7 is an internal circuit configuration diagram of the conventional example of FIG. 6. 8... Photoelectric conversion element (light emitting element), 9... Photoelectric conversion element (light receiving element), 9a... Light receiving window section,
13...Signal processing circuit, 21...Substrate, 22.Bend/conductor. 23... Resistance% 24... Chip-like device, 34... Transparent resin, 35... Insulating material. Figure 1 Figure 3 A J Procedural amendment @ (voluntary) 177 days in 1988

Claims (1)

[Claims] An unpackaged photoelectric conversion element device is placed on a ceramic, glass, or other substrate on which resistors, conductors, etc. of a signal processing circuit are printed, and at least the light receiving window of the photoelectric conversion element is covered with a transparent packaging material. An optical sensor unit characterized in that the entire substrate is covered with a fired insulating material.