Photo-electronic conversion apparatus with light pattern discriminator

A plurality of photovoltaic devices (e.g., solar cells) connect with each other and form a photo-electric conversion apparatus. The photovoltaic devices concerned are so connected with each other that when a given pattern of light is irradiated upon the photo-electric conversion apparatus concerned, the electrical output generated when the whole of it is irradiated is smaller than that generated when some parts of it are irradiated. Since an electronic system equipped with this apparatus as a power supply can be designed to work when the apparatus is irradiated with such a pattern of light that irradiates only a part of the apparatus, an electronic system having such an identifying faculty can be made easily. Further, an apparatus like this type may be made by connecting the elements of this apparatus in series or in reverse direction to form units, and by connecting this plurality of units in series and/or in parallel.

BACKGROUND OF THE INVENTION 
This invention relates to a photo-electric conversion apparatus which 
generates electricity when irradiated by light and more particularly 
relates to a photo-electric conversion apparatus which is designed to 
generate an electric output corresponding to a previously established 
pattern of light applied thereto. 
Conventional photo-electric apparatuses have had a plurality of 
photovoltaic devices (e.g., thin-film solar cells) formed on substrates 
and connected electrically in series, which are exemplified in Japanese 
Patent Publication No. 54,513/1983 and U.S. Pat. No. 4,042,418. 
By employing that form of connection, they generate the electric output 
required for operating electronic apparatuses. 
SUMMARY OF THE INVENTION 
It is an object of this invention to readily increase the operating 
efficiency of a coded card, such as a cash card or identification card, by 
giving a discrimination faculty to a photo-electronic conversion apparatus 
which is incorporated as a power supply in such a recognition card 
containing an IC or LSI. 
To this end, this invention presents an apparatus which is, by using a 
plurality of photovoltaic devices, so connected as to generate less 
electric output when all of the devices are irradiated than is generated 
when only some of them are irradiated. An electronic apparatus having such 
photovoltaic devices as a power supply works only when it receives 
irradiation of light rays forming a particular pattern that cuase higher 
electric output of the photovoltaic devices. Thus an apparatus of this 
kind allows easy detection of whether or not it is working correctly. 
Further, a connection of this kind can be easily made by connecting in 
series or parallel a plurality of units which consist of devices connected 
in parallel and in reverse direction.

DETAILED DESCRIPTION OF THE INVENTION 
One of the basic arrangements of this invention is illustrated in FIG. 1a. 
Photovoltaic devices 1 are respectively given numbers from 1 to 12. The 
photovoltaic devices No. 1 and No. 2 are connected together in parallel 
and in reverse direction. It can be easily understood that with this sort 
of connection there is no electric output when both the photovoltaic 
devices No. 1 and No. 2 are irradiated over the whole of their surfaces. A 
pair of photovoltaic devices connected in this way is hereinafter referred 
to as "a unit". Photovoltaic devices No. 3 and No. 4, No. 5 and No. 6, No. 
7 and No. 8, No. 9 and No. 10, and No. 11 and No. 12 also respectively 
compose units and are connected in series. In this form of connection, if 
all of these photovoltaic devices are irradiated, the circuit generates no 
voltage between terminals 2. And the largest electric output between 
terminals 2 occurs at the time when all of devices connected in the same 
direction of polarity are irradiated. 
Since the electric output varies in dependence upon which of the 
photovoltaic devices are irradiated, it is conversely possible to identify 
the pattern of light by detecting the electric output. Thus some patterns 
of light will generate a sufficiently large electric output for an 
electronic apparatus to be operated. 
Consequently, a cash card incorporated with the photoelectric conversion 
apparatus of this invention has a discriminating faculty that allows users 
to employ it only in a cash dispenser having a particular irradiating 
pattern. This discriminating faculty does not have the defect of being 
influenced by a magnetic field as in the case of maintaining records by 
magnetic recording, nor does it have the disadvantage of disappearing when 
the power supply is cut off as in the case of a semiconductor memory. This 
faculty is in contrast simple, and has high reliability. 
Other basic arrangements of this invention are respectively illustrated in 
FIGS. 1b and 1c. 
Each unit may be composed of more than two photovoltaic devices. As a 
matter of course, there will be no problem even if the characteristics of 
the devices are different from each other. 
Moreover, the photo-electric conversion apparatus of this invention can, of 
course, be incorporated in any kind of electronic system, as well as in ID 
cards and cash cards provided with electronic devices such as ICs, LSIs, 
etc. 
Further, since the photovoltaic devices employed in this invention are 
so-called "solar cells" made from Si, GaAs, amorphous Si, etc, it is also 
possible to dispose a multiplicity of units on a single substrate. 
This photo-electric conversion apparatus can, of course, be used as a power 
supply for electronic systems, or it can be applied to them merely as an 
identifying apparatus. 
On connecting the units, resistances, diodes, etc. can also be connected to 
them, according to need. It is possible for each unit itself to include 
electronic elements such as resistances, diodes, etc. in addition to the 
solar cells. 
It is possible, according to this invention, to provide a photo-electric 
conversion apparatus (e.g., so-called solar cells) having a discriminating 
faculty for a pattern of irradiated light which will popularize the 
electronic systems equipped with such a low-cost discriminating faculty, 
and have a tremendous influence upon the current momentum toward the 
so-called "information society". 
Example 
FIG. 2 is a plan view of a unit consisting of two photovoltaic devices. 
FIG. 3(a) is a side elevation as viewed in the direction indicated by the 
arrow I of FIG. 2. 
FIG. 3(b) is a side elevation as viewed in the direction indicated by the 
arrow II of FIG. 2. 
A transparent electrode 20 is formed using conductive glass. Next amorphous 
Si layer 3 is formed, consisting of three layers: p-type, intrinsic, and 
n-type layers; the respective film thickness of these layers are 100 
.ANG., 5000 .ANG., and 300 .ANG.. Electrodes 4 are formed on the layer 3. 
The points A and B thereon are terminals for connection to other units. 
Five units each having the above-described construction are connected with 
each other in the manner shown in FIG. 1. These units generate electric 
output-0.03 V when all of them are irradiated, and 3.2 V when one side of 
each of them is irradiated, each side having the same polarity.