JPH04127584A - Light emitting element array - Google Patents

Abstract

PURPOSE:To enable a light emitting element array to be remarkably enhanced in photosensitivity by a method wherein a controllable current is made to flow through a first control electrode from an outer terminal corresponding to optical data which are made to irradiate the light emitting element. CONSTITUTION:A voltage is supplied to a feed line 1 of a transfer clock phi1 and a light emitting thyristor T1 is irradiated with light. At this point, a photocurrent iP is made to flow through the light emitting thyristor T1. Then, when a control pulse phiP is made to decrease in voltage, instantaneously a displacement current iC is made to flow through a capacitor C1. The current iC enables a current iC1 to be extracted from a gate G1 of a T1. The current iC1 is smaller than the current iC, and a current obtained by subtracting iC1 from iC is correspondent to a current which flows through a gate load resistor RL1. The current tC1 induces a current iC2 which flows between the anode and the cathode of the light emitting thyristor T1. The current iC2 is as large in intensity as the product of the current iC1 and a current amplification factor beta.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a light emitting element array in which optical information can be written and has an optical information transfer function. The present invention relates to a light emitting element array provided with arithmetic functions.

[Summary of the Invention] The present invention is provided with a mechanism for injecting a current into the first control electrode of a light emitting element, and the injected current turns on the light emitting element with a small photocurrent. This is a light emitting element array that makes it possible to greatly improve sensitivity. Furthermore, the light sensitivity can be controlled externally,
This is a light emitting element array that can realize the OR function and AND function of optical information.

[Conventional technology]

As a conventional light emitting element array, Japanese Patent Application Laid-Open No. 2-14584
There are some things described in the No. FIG. 4 shows an equivalent circuit diagram of such a conventional light emitting element array.

In FIG. 4, T(0) to T(5) are light emitting thyristors (light emitting elements), and D0 to D are light emitting thyristors T(
This is a coupling diode (unidirectional electric element) that connects the gates (first control electrodes) of T(5) to T(5). In addition, RLO~Rtz is the gate load resistance, and R
AG~RA! is the anode load resistance.

VGK is the power supply voltage of the DC power supply, and in this conventional example, it is 5 [
■] is set. φ6 and φ2 are transfer locks,
φS is a start pulse.

Next, the operation of the light emitting element array shown in FIG. 4 will be explained.

T(0) to T(5) anodes (second
The turn-on voltage between the control electrode) and the cathode is higher than the gate voltage ■6 by the diffusion potential ■d□ (approximately 1 [■]). First, as a start pulse φ, the power supply voltage 5
A voltage greater than 1 [73] than [V] is supplied to the supply line. At this time, the light emitting thyristor T(0) is turned on. At this time, the gate load resistance PL is also applied from the gate of T(0).
It sinks current through O.

Therefore, the potential of the gate becomes approximately zero volts.

At the same time, current also flows into the coupling diode D0 from the circuit on the right side of the figure, and a potential difference of the forward rising voltage VDdifC of the coupling diode (approximately 1 (V)) is generated across the coupling diode D0. Therefore, the gate voltage of the light emitting thyristor T(0) is approximately 1 [V).

At this time, the gate voltage of the light-emitting thyristor T(2) is approximately 2 (the gate voltage of the VL light-emitting thyristor T(3) is approximately 3 [V]) due to the difference in potential between the coupling diodes D0 and D2. In other words, the turn-on voltage is T(
1), T(2), and T(3), each of which has a luminous cyrisk of 2
[V], 3 EV), 4 (V).

In this state, if a voltage pulse of 2 to 3 [■] is applied to the supply line as transfer lock φ2, the light emitting thyristor T
Only (1) turns on. Then, when the supply of the start pulse φ is stopped, T(0) turns off and the on state moves to the right side of the figure. Thereafter, in the same way, by alternately adding transfer locks φ3 and φ2 to those supply lines, the on state moves to the right side in the figure.

Note that when the on state moves from light emitting thyristor T(2) to T(3), the off state light emitting thyristor T(
The gate voltage of 1) becomes 5 [V] of the power supply voltage because the coupling diode D becomes reverse biased, and the turn-on voltage of T(1) becomes 6 [■]. Therefore, the light emitting thyristor T(1) is never turned on.

The equivalent circuit shown in FIG. 4 can simultaneously light up and move a plurality of light emitting lights.

In the case of driving by two-phase transfer lock (φ3, φ2), two elements (light-emitting thyristors) can be turned on at the rate of one element. Further, in the case of driving by three-phase transfer lock (φ1 to φ3), it is possible to turn on up to one element out of three elements. This ON state (optical information) can be written by using the start pulse φ or by light.

This takes advantage of the phenomenon that the turn-on voltage of the light-emitting cyrisk decreases.

This method has already been described by Kuroda et al. in 1990.
Spring Applied Physics Association Lecture, 30p-F-11
It has been reported in

In addition, as a second conventional light emitting element array,
There is one described in Japanese Patent No. 238962. FIG. 5 shows an equivalent circuit diagram of this second conventional example. In the configuration shown in FIG. 5, the connection between the gates of each light emitting thyristor T(-2) to T(2) is made using a coupling diode D as shown in FIG.
This was done using a coupling resistor R4 instead of 0 to D5. In this case, the effect of lowering the gate voltage spreads symmetrically to the left and right of the on-state light-emitting thyristor (for example, T(0)), so as shown in FIG.
, φ2), three-phase transfer locks (φ1 to φ3) are required.

Next, FIG. 6 shows an equivalent circuit diagram of a third conventional example. In addition, in FIG. 6, each light emitting thyristor T (-2)
~T(2) are each constituted by two transistors T□ and T. Further, R5 and R8 are resistors.

This conventional example connects the gates of the light-emitting thyristors T(-2) to T(2) with a coupling resistor R1, and utilizes the fact that the gate voltage is transmitted via the coupling resistor R1. Now, if the light emitting thyristor T(0) is on, the voltage at its gate (i.e., the base of the transistor Try(.) increases, and the light emitting thyristor T(1), T
(-1) gate voltage increases. That is, the base voltages of transistors T rz (11, T rt (-11) rise. Therefore, these transistors T, 2 (1
), T rz (-11)'s current drive capability increases, and the turn-on voltage of the light emitting thyristors T (1) and T (-1) decreases.

On the other hand, for the light emitting thyristors T(2) and T(-2), the gate voltage decreases because current flows through the coupling resistor RI. For this reason, the light emitting thyristor T(1
), T(-1), the turn-on voltages of the light emitting thyristors T(2), T(-2) are higher. Utilizing this difference in turn-on voltage, on-state transfer is possible by three-phase transfer locks φ, ~φ.

Next, FIG. 7 shows an equivalent circuit diagram of a fourth conventional example. In addition, in FIG. 7, each of the light emitting thyristors T(4) to T
(2) each have two transistors T1. ,T. Note that Ro is resistance. Also,
This equivalent circuit is constructed by applying a current mirror circuit.

Now, in FIG. 7, it is assumed that the light emitting thyristor T(0) is in the on state (light emitting state). At this time, transistor T1
□,. , and transistor T71. . , constitute a current mirror circuit, and the light emitting thyristor T(0
) The same current as that flowing through the transistor T r :+
Flows into (.). Therefore, the voltage at the gate G1 becomes approximately zero volts. Therefore, the turn-on voltage of the light emitting thyristor T(1) decreases to about 1 (V). On the other hand, since the gate voltage of the light emitting thyristor T (-1) is the power supply voltage VGK (usually 5 (V)), the turn-on voltage is approximately 6 [■]. Using this difference in turn-on voltage, a transfer operation can be performed by two-phase transfer locks φ3 and φ2.

Furthermore, as a fifth conventional light emitting element array,
There is one described in Japanese Patent No.-14584. FIG. 8 shows an equivalent circuit diagram of this fifth conventional example. This conventional example is a light emitting element array using optical coupling.

In Fig. 8, the light emitting thyristors T (-2), T (2)
), when light is incident, a photocurrent flows inside and its turn-on voltage decreases. Assuming that the light emitting thyristor T(0) is now emitting light, the light L resulting from the emitted light is incident on the adjacent light emitting thyristors T(1) and T(-1), thereby lowering the turn-on voltage. Light emitting thyristor T(2), T
For (-2), the turn-on voltage remains unchanged because no light is incident. Using this, transfer lock φ1~
By supplying φ3 to these supply lines, the light emission state can be transferred.

[Problem to be solved by the invention]

When applying the light emitting element array having the self-scanning function described in the above conventional example to optical information processing such as optical computing, the function of writing information using light is important. However, each of the light emitting element arrays of the above-mentioned prior art techniques has poor photosensitivity and requires a considerably high light emission intensity from the light emitting device. For this reason, it is necessary to supply a considerably large amount of power to the device that emits light, and there is a problem that low power consumption cannot be achieved as a system.

SUMMARY OF THE INVENTION An object of the present invention is to provide a light emitting element array that solves the problems of the prior art described above and makes it possible to turn on the light emitting elements with a small photocurrent, that is, to greatly improve photosensitivity.

Another object of the present invention is to provide a light emitting element array whose optical sensitivity can be controlled externally and which can realize an OR function and an AND function of optical information.

[Means to solve the problem]

In order to achieve the above object, the light emitting element array of the present invention includes a plurality of light emitting elements arranged, each having a first control electrode for controlling a threshold voltage for light emission operation, and each of the above The first control electrode of the light emitting element is connected to the first control electrode of at least one light emitting element located nearby, directly or through an electric element having a first electric resistance or electrically unidirectionality. A second control electrode for controlling light emission is provided to each of the light emitting elements, and a plurality of supply lines supplying voltage or current from the outside to each of the second control electrodes. A plurality of light emitting element arrays connected to each other, each having a first control electrode for controlling a threshold voltage for light emitting operation, and a threshold voltage for starting light emission that changes depending on the intensity of incident light. of light emitting elements are arranged, and the light emitted from each of the light emitting elements emit light from a small number of nearby light emitting elements.
Each of the light emitting elements is provided with a second control electrode for controlling light emission, and a voltage is applied to each of the second control electrodes from the outside. Alternatively, it is a light emitting element array to which a plurality of supply lines supplying current are connected, and the first
means for passing a controllable current through the control electrode from an external terminal.

According to a preferred embodiment of the light emitting element array of the present invention, the means for flowing a controllable current from the external terminal connects the first control electrode of each light emitting element and the external terminal. Equipped with a capacitor. More preferably, the capacitor is set to a different capacitance value depending on each of the light emitting elements.

According to a preferred aspect of the light emitting element array of the present invention, the means for flowing a controllable current from the external terminal connects the first control electrode of each of the light emitting elements and the external terminal. A diode and an electrical resistance are provided. More preferably, the electrical resistance is set to a different resistance value depending on each of the light emitting elements.

[Effect]

The means for flowing a controllable current from the external terminal has a mechanism for injecting the current into the first control electrode of each light emitting element. Therefore, the light emitting element can be turned on even with a small photocurrent due to the injected current.

For example, the mechanism includes a capacitor connected to the first control electrode of each light emitting element. A photosensitivity control pulse is supplied to the other end of this capacitor from an external terminal. and,
When a photosensitivity control pulse is applied, a displacement current flows through the capacitor in response to a voltage change. This displacement current becomes a current flowing to the first control electrode of the light emitting element. If this displacement current suffices a considerable proportion of the current required to turn on the light emitting element, the light emitting element can be turned on with a small photocurrent. Therefore, the photosensitivity of each light emitting element is greatly improved.

Further, the above-mentioned injection current is set to a different amount for each light emitting element of the light emitting element array. Then, 1
When two pieces of optical information are incident on one light emitting element, an OR function or an AND function can be generated.

According to the present invention, it is possible to more easily write information using light. Therefore, it is suitable for constructing a system with low power consumption as an element for optical computing.

〔Example〕

<Embodiment 1> FIG. 1 is an equivalent circuit diagram showing a first embodiment of the present invention. In FIG. 1, this equivalent circuit basically employs the configuration of the light emitting element array having the self-scanning function shown in FIG. 4. The configuration of the light emitting element array in FIG.
A capacitor CI or C1 is connected to the light emitting element shown in FIG. It is different from the array. In FIG. 1, the same components as in FIG. 4 are given the same reference numerals. Also, A1
~A, is an anode.

Next, the operation of the light emitting element array shown in FIG. 1 will be explained.

If the control pulse φ2 is not supplied to the supply line, the capacitors C,,C, do not function and operate exactly as in the conventional example shown in FIG. Now, the case where optical writing is performed will be explained. 2-phase transfer lock φ2
When performing a transfer operation, information can only be written to every other light emitting thyristor, so
Light emitting unit 1° connected to the supply line of transfer lock φ1
A case will be explained in which only the listers T(1), T(3), and T(5) are turned on.

The voltage of the lock φ is transferred to the light-emitting thyristor T(1), T
(3), set to a high level such that T(5) does not turn on. Then, optical information is applied to each of the light emitting thyristors T(1) to T(5). Thereafter, the photosensitivity control pulse φ is set to a low level and is supplied to the supply line. A certain amount of time is required between the time of this light irradiation and the time of supply of the control pulse φD. After light is irradiated, photocharges are accumulated inside the light emitting thyristors T(1) to T(5) until a current proportional to the amount of light flows through the light emitting thyristors T(1) to T(5). This is because it is necessary.

FIG. 2 shows an extracted diagram of the light emitting thyristor T(1) of FIG. 1 and its peripheral circuits. In FIG. 2, the light emitting thyristor T(1) has a PNPN structure. Then, a transfer lock φ is supplied to the P-type semiconductor layer 10 which becomes the anode (A I) via the resistor RAI, and N which becomes the cathode
The shaped semiconductor layer 13 is grounded. The N-type semiconductor JWII, which becomes the gate (GO), is connected to the power supply voltage VG via the resistor RLI.
II, and is connected to the DC power supply of II and receives a photosensitivity control pulse φ via a capacitor C1.

connected to the supply line. Note that 12 is a P-type semiconductor layer.

In FIG. 2, it is assumed that a voltage is supplied to the supply line of the transfer lock φ, and light is irradiated to the light emitting thyristor T(1). At this time, the photocurrent Sp is the light emitting thyristor T(1)
flows to Next, when the voltage of the control pulse φde is lowered, a displacement current ic flows into the capacitor CI at that moment.

This current ic is the current ic+ from T(1) (G+)
The current ic+ is smaller than the current ic, and the current difference between them corresponds to the current flowing through the gate load resistor RLI.This current ic+ passes between the anode and cathode of the light emitting thyristor T(1). A current icz is induced.This current i■ has a magnitude obtained by multiplying the current ic+ by the current amplification factor β.

When the threshold current for turning on the light emitting thyristor T(1) is ith, the condition for turning on the light emitting thyristor T(1) is I th< i p+ict= i p+βic+. From this relationship, the photocurrent i can be reduced by setting the current ict near the threshold current Ith. That is, the photosensitivity of the light emitting thyristor T(1) can be improved.

In addition, although the light emitting thyristor T(1) was explained as an example in FIG. 2, other light emitting thyristors T(2) shown in FIG.
~T(5) operates similarly.

In FIG. 1, a voltage is supplied to the supply line of the transfer lock φ, and optical information is transmitted to the light emitting thyristor T (1
), and a control pulse φ is supplied to the supply line to turn on the light emitting thyristor T(1). The subsequent transfer of the on state is performed in exactly the same manner as in the conventional example shown in FIG. As long as a voltage pulse is supplied to its supply line as the photosensitivity control pulse φ, the capacitor C
,,C, have no effect on the operation.

Now, assume that CI is a capacitor connected to each of the gates of light emitting thyristors T(1), T(3), and T(5) connected to the supply line of transfer lock φ. Furthermore, 02 is a capacitor connected to each of the gates of the light emitting thyristors T(2) and T(4) connected to the supply line of the transfer lock φ2. And each capacitor C
+ and Cz have different capacitance values. At this time, the above-mentioned displacement current iCO amount is different between the capacitors C4 and C2, and the photosensitivity of the respective light emitting cyrisks can be set to different states. By utilizing this, when two pieces of light information are incident on one light-emitting cyrisk, if the photosensitivity is increased, the light-emitting cyrisk will be turned on by either one of the light information. That is, the luminescent thyrisk can perform the OR function.

On the other hand, if the light sensitivity of the light-emitting cyrisk is lowered, it will turn on when both types of light information are incident. That is, the luminescent thyrisk can perform the AND function. In this way, the light sensitivity of the light emitting element arrays T(1) to T(5) can be greatly improved, and not only this, but also a light calculation function can be provided.

<Embodiment 2> FIG. 3 is an equivalent circuit diagram showing a second embodiment of the present invention. The structure of the light emitting element array in FIG. 3 has a diode D' and a resistor R□ instead of the capacitors C1 and C2 in FIG.
,RP! This is different from the light emitting element array shown in FIG. 1 in that the light emitting element array shown in FIG. In FIG. 3, the same components as in FIG. 1 are given the same reference numerals.

Next, the operation of the light emitting element array shown in FIG. 3 will be explained.

Now, the light sensitivity control pulse φ, the power supply voltage ■. The same voltage as (
For example, set it to 5 [V)]. In this case, diode D' becomes reverse biased and no current flows through diode D'. Therefore, the present light emitting element array operates in exactly the same way as the conventional example shown in FIG.
Suppose that the voltage of is set to zero volts, for example. At this time, diode D' is biased in the forward direction and current iI flows through it. A part of this current i flows through the resistor Rt+ (or RL), but most of it flows through the light emitting thyristor T(1)~
It flows out from the gates (C1 to C,) of T(5).

The current i flowing through the diode D° is limited by RPI (or R) connected in series with it. This current 10 is limited by the capacitors C1 and C2 described in the first embodiment.
is the same as the displacement current ic in the light emitting thyristor T(1
) to T(5). Therefore, for exactly the same reason as the first embodiment, the light emitting thyristor T
The photosensitivity of (1) to T(5) can be improved.

Now, in Fig. 3, light emitting thyristors T(1), T(3), T(5) connected to the supply line of transfer lock φ1 are shown.
) is connected to each of the gates of φ through a diode D'' as RPI.In addition, the light emitting thyristors T(2) and T(4) connected to the supply line of the transfer lock φ,
Let RP2 be a resistor connected to each of the gates of , via a diode D'. And each resistance RPI,
The resistance value of RP□ is made different.

At this time, the amount of the above-mentioned electricity io will be different between the resistors R□ and RP2, and the photosensitivity of the respective light-emitting cyrisks can be set to different states. With this, the OR function and the AND function can be achieved in the same manner as in the first embodiment.

Note that the light emitting element array of the embodiment described above shows a case where the structure of the light emitting element array shown in FIG. 4 is applied. However, the present invention is not limited to this configuration, and is applicable to other conventional examples as well.

For example, in FIG. 5, the light emitting thyristors T (-2) to T (
2) gate (capacitor CI in the G-2 to G-ri part,
C2 or diode D and resistor RF
I and RP2 may be provided. In addition, in FIG. 6, capacitors C1 and C2 are provided at the base of transistor Trl (-41 to TrlH), or a diode D
゛ and a resistor RP1% RP□ may be provided.

Furthermore, in FIG. 7, the light emitting thyristors T(-1) to T(2
), the light-emitting thyristors T(-2) to T(2), which are in the open state in FIG.
) may be provided with capacitors C1 and C2, respectively, or a diode D' and a resistor RP1%Rrz.

[Effects of the Invention] Since the present invention is configured as described above, it produces the effects described below.

That is, by flowing a controllable current from an external terminal (supplying a photosensitivity control pulse), it is possible to provide a light emitting element array that can significantly improve photosensitivity. Therefore, the device on the light emitting side does not require a large amount of power, and the system can achieve low power consumption.

In addition, by individually controlling the photosensitivity of the light emitting elements,
It is possible to provide a light emitting element array that can realize the AS function and the AND function of optical information.

[Brief explanation of the drawing]

FIG. 1 is an equivalent circuit diagram showing the first embodiment of the present invention, and FIG.
The figure is a diagram for explaining the operation of the first embodiment, FIG. 3 is an equivalent circuit diagram showing the second embodiment of the present invention, and FIG. 4 is a diagram for explaining the operation of the first embodiment.
Fig. 5 is an equivalent circuit diagram showing the second conventional example, Fig. 6 is an equivalent circuit diagram showing the third conventional example, and Fig. 7 is the fourth conventional example. Equivalent circuit diagram FIG. 8 is an equivalent circuit diagram showing a fifth conventional example. In addition, in the codes used in the drawings, T (-2) to T (5)---Light-emitting thyrisk (light-emitting element) G2-G5---11111-Gate (first Control electrode) A, ~As-...--111-
--・-Anode (second control electrode) Ro-・-m--
----------...-Coupling resistance (first electrical resistance) D0
〜D 5−−−−−−−−−−・−・Diode (
Unidirectional electric element) φ1, φ2...---1--Transfer lock φF
---・-・-1----Photosensitivity control pulse 14-・
−・−−−1−・・・・−External terminals CI, Ct・・・・
−・−・・・−Capacitor D′・−・・−−−−−−m
-.-Diode R□, RP□--1-----.-Resistance (second electrical resistance).

Claims (1)

[Claims] 1. First for controlling the threshold voltage for light emission operation
A plurality of light emitting elements each having a control electrode are arranged, and the first control electrode of each of the light emitting elements is located near the first control electrode of at least one of the light emitting elements.
A second control electrode is connected to the control electrode directly or via a first electrical resistance or an electrical element having electrical unidirectionality, and is provided with a second control electrode for controlling light emission of each of the light emitting elements. A light emitting element array, in which a plurality of supply lines for externally supplying voltage or current are connected to each of these second control electrodes, or a light emitting element array for controlling a threshold voltage for light emitting operation. A plurality of light emitting elements each having one control electrode and whose threshold voltage for starting light emission changes depending on the intensity of incident light are arranged, and each of the light emitting elements emit light from at least one control electrode located nearby. Each of the light emitting elements is provided with a second control electrode for controlling light emission, and a voltage or voltage is applied to each of the second control electrodes from the outside. A light emitting element array in which a plurality of supply lines supplying current are connected, the current being controllable from an external terminal to the first control electrode in accordance with optical information irradiated to the light emitting elements from the outside. A light-emitting element array characterized by comprising means for flowing. 2. In the light emitting element array according to claim 1, the means for flowing a controllable current from the external terminal includes a capacitor connecting the first control electrode of each of the light emitting elements and the external terminal. A light emitting element array comprising: 3. The light emitting element array according to claim 2, wherein the capacitor is set to a different capacitance value depending on each of the light emitting elements. 4. In the light emitting element array according to claim 1, the means for flowing a controllable current from the external terminal includes a diode connecting the first control electrode of each of the light emitting elements and the external terminal. A light emitting element array comprising a second electric resistance. 5. The light emitting element array according to claim 4, wherein the second electrical resistance is set to a different resistance value depending on each of the light emitting elements.