DE3804200A1 - Photoelectric line sensor - Google Patents

Abstract

A photoelectric line sensor (array) is described which has a multiplicity of individual elements which are arranged on one chip. The interrogation as to whether light has fallen onto each of the individual elements is carried out with the aid of a particularly suitable read-out or evaluating method (coding/decoding). Only a minimum of connections to the outside is now required. <IMAGE>

Description

The invention relates to a photoelectric line sensor (array) a large number of individual elements in a line on one block arranged.

For evaluation, it must be queried whether the individual photo elements were each exposed to light. Up to now, 65 connections ( Fig. 1) were required to control 64 individual elements. A very complex bonding process is necessary for their production.

The object of the invention is to provide a module that is easy to manufacture to create the type in question with a minimum of connections Outside.

This object is achieved by the features of patent claim 1. Training and further training are included in further claims.

The evaluation or readout method is expressly part of the invention (digital), as well as combinations and subcombinations of the characteristics that in claims, description and drawing of an embodiment are included.

The main advantages of the invention are:

• 1. The integration of the photoelectric decoder elements on one module: α -Si line sensor (no hybrid structure with crystalline chips required).
• 2. The minimization of external electrical connections (avoidance of Bond technology, you only need two electrical connections).
• 3. The digital optical bus can be retrofitted and needs no high adjustment accuracy during manufacture.

The invention is e.g. shown in the accompanying figures. It demonstrate:  

Fig. 1 is a photoelements line (array);

Figure 2 is a circuit with 64 elements.

Fig. 3 is a circuit having bus line;

Fig. 4 is an optical bus;

Fig. 5 shows a series and parallel connection.

For the control of only 64 individual detectors 1 , 65 connections on one line ( FIG. 1) and a very complex bonding process in the manufacture were previously required. A first reduction is achieved by a matrix readout method ( FIG. 2), in which the number of connections 3 is reduced to 16. A further reduction in the control lines (connections) can be carried out by using a binary code and the decoders 4 for each element 1 on the line sensor ( FIG. 3).

The number of external connections is now only seven or eight with power supply. The digital bus 5 (6 bit) and the decoder units 4 have the following structure:

The design specification for a decoder element 8 is: All decoder detectors which are to detect a "one" are connected in series and those which are to recognize "zeros" are connected in parallel. The digital control takes place via an optical bus 5 (for example glass fiber bus 6 or fluorescence plate bus 7 , FIG. 4), which does not have to be integrated on the line sensor, but can be brought up externally. The photodetectors of the decoder element 8 are now integrated in the line sensor. The photodetectors of a special decoder element are connected according to the position that is to be decoded. If code 101101 is present on the optical bus, the 45th decoder element should be addressed.

Fig. 5 shows the circuitry of the decoder photodiodes of the 45th decoder element. This decoder element supplies a readout voltage for the 45th individual photodetector of the line sensor when the binary number 101101 appears on the optical bus.

A line sensor is e.g. a building block made up of a line of many Single photodetectors (e.g. 8 pieces / mm) exist. With a total length Of about 210 mm, such a module contains 1680 photodetectors have to be controlled in the event of a query.

Claims (8)

1. Photoelectric line sensor (array), consisting of a line of many individual photodetectors (photo elements), which are combined on a module and are controlled for detection, characterized in that all the individual elements are connected to a common control line for connecting them and the The number of connections to the outside is reduced to a minimum through a digital readout or evaluation process. 2. Line sensor according to claim 1, characterized in that the Module contains 64 individual elements and by using a matrix Provide the readout procedure with two times eight connections to the outside is. 3. Line sensor according to claim 1, characterized in that it by using a binary code for evaluation only by means of six Connections to the outside on a bus line is provided. 4. Line sensor according to claim 3, characterized in that the Bus line is designed as an optical bus. 5. Line sensor according to claim 4, characterized in that the Attach the optical bus outside the module (arrays) later is cash. 6. Line sensor according to claim 5, characterized in that the Bus is a fiber optic bus or fluorescent plate bus.   7. Line sensor according to one of the preceding claims, characterized characterized in that the individual elements are made of amorphous silicon - in thin-film technology - are. 8. Line sensor according to one of the preceding claims, characterized characterized in that all individual elements that detect a "one" should be in series and all individual elements that detect a "zero" should be connected in parallel.