Light emitting four layer device and improved circuitry thereof

Claim 2

Apparatus for producing light and electrical pulses comprising a two terminal PNPN four-layer light emissive semiconductor element formed by a single epitaxial process exhibiting a forward voltage current characteristic including a current-controlled negatiVe resistance region with a high impedance state and a low impedance state in the forward voltage area, said semiconductor element showing light emission at room temperature at the high and low impedance states included in the negative resistance region in the forward voltage area wherein the intensity increases with the current flowing through said element in both the positive and negative regions of the forward voltage area, impedance means connected in series with one terminal of said element, forward biasing means connected across aid impedance means and said element in series to bias said element in the forward voltage area, said biasing means and said impedance means being selected to provide a load line which intersects the voltage-current characteristic at only one point, said point being in said negative resistance region, capacitor means connected in shunt with said semiconductor element, said capacitor being alternately charged and discharged to concurrently provide a pulsating electrical (output) current and a pulsating light output from said semiconductor element, whereby said current and output may be selectively utilized to activate means responsive thereto.

Claim 3

Apparatus for producing light and electrical pulses according to claim 1 wherein said forward biasing means constitutes a variable voltage source alternating with time about a zero axis.

Claim 4

Apparatus for producing light and electrical pulses according to claim 1 wherein said forward biasing means constitutes power source including a constant voltage control.

Claim 5

Apparatus for producing light and electrical pulses according to claim 1 wherein the last said means comprises means connected effectively in series with said semiconductor element and storing a charge corresponding to the current flowing through said element and a switching element controlled by the charge stored by the last said means and the voltage produced by said forward biasing means.

Claim 6

Apparatus for producing light and electrical pulses according to claim 1 including a switching element connected in parallel with said semiconductor element and controlled by a liquid level, said switching element shifting the operating point of said semiconductor element to the positive resistance region of the voltage-current characteristic thereof.

Claim 7

Apparatus for producing light and electrical pulses according to claim 1 including means connected in parallel with said semiconductor element and supplying positive and negative trigger signals thereto to shift the operating characteristic selectively between the constant voltage region and the positive resistance region of the voltage-current characteristic of said semiconductor element.

Claim 8

Apparatus for producing light and electrical pulses according to claim 1 wherein said impedance means has a value greater than the value of the negative resistance of said element and the voltage of said biasing means divided by the value of said impedance means being greater than the threshold current of said element but smaller than the hold current thereof.

Claim 9

Apparatus for producing light and electrical pulses comprising a two terminal PNPN four-layer light emissive semiconductor element formed by a single epitixial process exhibiting a forward voltage current characteristic including a current-controlled negative resistance region with a high impedance state and a low impedance state in the forward voltage area, said semiconductor element showing light emission at room temperature at the high and low impedance states included in the negative resistance region in the forward voltage area wherein the intensity increases with the current flowing through said element in both the positive and negative regions of the forward voltage area, forward biasing means said impedance means being selected to provide a load line which intersects the voltage-current characteristic at only one point, said point being in said negative resistance region, capacitor means connected in shunt with saiD semiconductor element, said capacitor being alternately charged and discharged to concurrently provide a pulsating electrical current and a pulsating light output from said semiconductor element whereby said current may be selectively utilized to activate means responsive thereto, the last said means including a light responsive switching element electrically interconnected with said semiconductor element and responsive to light emitted by said semiconductor element to modify the characteristics of the semiconductor element output.

Claim 10

Apparatus for producing light and electrical pulses comprising a two terminal PNPN four-layer light emissive semiconductor element formed by a single epitixial process exhibiting a forward voltage current characteristic including a current-controlled negative resistance region with a high impedance state and a low impedance state in the forward voltage area, said semiconductor element showing light emission at room temperature at the high and low impedance states included in the negative resistance region in the forward voltage area wherein the intensity increases with the current flowing through said element in both the positive and negative regions of the forward voltage area, forward biasing means said impedance means being selected to provide a load line which intersects the voltage-current characteristic at only one point, said point being in said negative resistance region, capacitor means connected in shunt with saiD semiconductor element, said capacitor being alternately charged and discharged to concurrently provide a pulsating electrical current and a pulsating light output from said semiconductor element whereby said current may be selectively utilized to activate means responsive thereto, the last said means including a light responsive switching element electrically interconnected with said semiconductor element and responsive to light emitted by said semiconductor element to modify the characteristics of the semiconductor element output.

Claim 11

Apparatus for producing light and electrical pulses comprising a two terminal PNPN four-layer light emissive semiconductor element formed by a single epitaxial process exhibiting a forward voltage current characteristic including a current-controlled negative resistance region with a high impedance state and a low impedance state in the forward voltage area, said semiconductor element showing light emission at roon temperature at the high and low impedance states included in the negative resistance region in the forward voltage area wherein the intensity increases with the current flowing through said element in both the positive and negative regions of the forward voltage area, impedance means connected in series with one terminal of said element, forward biasing means connected across said impedance means and said element in series to bias said element in the foroward voltage area, said biasing means and said impedance means being selected to provide a load line which intersects the voltage-current characteristic at only one point, said point being in said negative resistance region, capacitor means connected in shunt with said semiconductor element, said capacitor being alternately charged and discharged to concurrently provide a pulsating electrical current and a pulsating light output from said semiconductor element whereby said current and output may be selectively utilized to activate means responsive thereto, and second impedance means and a series connected light responsive switch interconnected in parallel with the first impedance means, said switch being responsive to light produced by said semiconductor element to connect said second impedance means in circuit with said first impedance means to shift the operation of said semiconductor element to the constant voltage region of the voltage-current characteristic thereof.

Claim 12

Apparatus for producing light and electrical pulses comprising a two terminal PNPN four-layer light emissive semiconductor element formed by a single epitaxial process exhibiting a forward voltage current characteristic including a current-controlled negative resistance region with a high impedance state and a low impedance state in the forward voltage area, said semiconductor element showing light emission at roon temperature at the high and low impedance states included in the negative resistance region in the forward voltage area wherein the intensity increases with the current flowing through said element in both the positive and negative regions of the forward voltage area, impedance means connected in series with one terminal of said element, forward biasing means connected across said impedance means and said element in series to bias said element in the foroward voltage area, said biasing means and said impedance means being selected to provide a load line which intersects the voltage-current characteristic at only one point, said point being in said negative resistance region, capacitor means connected in shunt with said semiconductor element, said capacitor being alternately charged and discharged to concurrently provide a pulsating electrical current and a pulsating light output from said semiconductor element whereby said current and output may be selectively utilized to activate means responsive thereto, and second impedance means and a series connected light responsive switch interconnected in parallel with the first impedance means, said switch being responsive to light produced by said semiconductor element to connect said second impedance means in circuit with said first impedance means to shift the operation of said semiconductor element to the constant voltage region of the voltage-current characteristic thereof.

Claim 13

Apparatus for producing light and electrical pulses according to claim 9 including an electro-acoustic transducer interconnected with and driven by said semiconductor element.