We claim:
1. A method of controlling voice communication between calling and called telephone stations each connected through a respective switch to a public switched telephone network (PSTN) region and remotely located from each-other, comprising the steps of:
routing a voice call between said calling and called stations in digital packet format through a path of a packet data network;
changing the route of said call from said packet data network path to a voice telephone network connection without terminating the call, thereby bypassing said packet data network while maintaining the call.
2. A method as recited in claim 1, wherein said changing step is responsive to a DTMF signal input by one of said stations.
3. A method as recited in claim 1, wherein said changing step comprises:
monitoring said packet data network during the course of transmission of said voice call through said path to determine a quality of performance level
comparing the performance level determined in said monitoring step with a predetermined threshold level; and
rerouting the call to the voice telephone network if the performance level of said packet data network as monitored in said monitoring step is below said predetermined threshold.
4. A method as recited in claim 3, wherein said data packet network is the Internet, which interfaces with a plurality of PSTN regions through respective Internet modules, and said rerouting step comprises:
transmitting a signal from an Internet module connected with the PSTN region of the calling station to the calling station switch;
in response to said signal, establishing a connection for said call from said calling station switch through the PSTN to a second switch coupled to the called station;
bridging the voice call at each of said switches to, the established connection; and
terminating communication of said call through said packet data network path.
5. A method as recited in claim 3, wherein said performance level is related to data flow rate and said predetermined threshold is a minimum acceptable voice transmission time, said monitoring step comprising:
transmitting at least one request packet through said data;
receiving at least one response packet; and
measuring the round trip time duration therebetween.
6. A method as recited in claim 4, wherein said predetermined threshold is a minimum acceptable data flow rate and said monitoring step comprises:
measuring the voice data packet pulses received per unit time period from the Internet at the Internet module connected to the PSTN region of the calling station.
7. A method as recited in claim 4, wherein said monitoring step comprises:
measuring the time variance between voice data packets received from the Internet at the Internet module connected to the PSTN region of the calling station; and
wherein said performance level is below said predetermined threshold if said measured time variance exceeds a maximum value.
8. A method as recited in claim 4, wherein said monitoring step comprises:
checking the sequence of voice data packets of the call received at the Internet module connected to the PSTN region of the calling station;
detecting whether voice data packets for the call have not been received in said checking step; and
said comparing step comprises determining whether the frequency of missed packets detected in said detecting step exceeds a maximum value.
9. A method as recited in claim 4, wherein said establishing step comprises:
transmitting a control signal from the PSTN region of said calling station to the PSTN region of said called station through a common channel signaling system path.
10. A method as recited in claim 3, wherein said data packet network interfaces with a plurality of PSTN regions through respective modules, and said rerouting step comprises:
transmitting a first signal from a module connected with the PSTN region of the calling station to the calling station switch;
transmitting a second signal from a module connected with the PSTN region of the called station to the called station switch;
in response to said first and second signals, establishing a connection for said call from said calling station switch through the PSTN to a second switch coupled to the called station;
bridging the voice call at each of said switches to the established connection; and
terminating communication of said call through said packet data network path.
11. A method as recited in claim 10, wherein said establishing step comprises:
transmitting an in-band control signal from the PSTN region of said calling station to the PSTN region of said called station through a voice communication trunk.
12. A communications network comprising:
a switched telecommunications network having interconnected central office switching systems and having subscriber lines connected to; said central office switching systems providing connection between terminals connected to said subscriber lines, each of said central office switching systems responding to a service request on a subscriber line connected thereto to, selectively provide a communication connection between the requesting line and another selected subscriber line through the switched telecommunications network;
a separate control network for said switched telecommunications network comprising a common channel interoffice signaling network including signal transfer points connected to said central office switching systems through signal switching points via links between said signal switching points and signal transfer points;
a data network separate from said switched telephone network comprising multiple remotely spaced routers for linking together paths of said data network using transmission control protocols to provide connectionless packet service between remote locations of said data network;
at least two of said central office switching systems having connected thereto an interface to said data network, said central office switching systems providing selective connection between said interfaces and the subscriber lines connected to each of said central office switching systems;
each said interface comprising means for monitoring said data network during the course of communication of a voice call between a first and a second of said subscriber lines through said data network to determine a quality of performance level in said data network, and means for providing a signal to said control network indicating that said performance level is unacceptable;
whereby said control network is responsive to said signal to reroute said voice call through said switched telecommunications network to bypass said data network while maintaining the call.
13. A communication network as recited in claim 12, wherein said central office switching systems comprise means responsive to said control network for bridging said first and second subscriber lines the rerouted switched telecommunications path.
14. A communications system comprising:
a public switched telecommunications network (PSTN) having a plurality of interconnected central office switching systems each connected to at least one subscriber line;
a data network separate from said switched telephone network comprising multiple remotely spaced routers for linking together paths of said data network using transmission control protocols to provide connectionless packet service between remote locations of said data network;
at least two of said central office switching systems connected to a respective interface to said data network, said central office switching systems providing selective connection between said interfaces and the subscriber lines connected to each of said central office switching systems; and
means for automatically rerouting a voice call between subscriber lines of said two central office switching systems that traverse said data network to a voice path in said PSTN in response to a predetermined condition, without terminating the existing voice call.
15. A communications system as recited in claim 14, wherein said predetermined condition is receipt of a DTMF signal input from one of said subscriber lines.
16. A communications system as recited in claim 14, wherein said predetermined condition is the occurrence of an unacceptable level of quality of performance of said data network, and each said interface comprises means for monitoring said data network during the course of transmission of said voice call through said data network.
17. A communications system as recited in claim 16, wherein said monitoring means measures voice data packet pulses received per unit time period from the data network.
18. A communications system as recited in claim 16, wherein said monitoring means transmits a request packet through said data network, receives a response packet, and measures the round trip time duration therebetween.
19. A communications system as recited in claim 16, wherein said monitoring means measures time variance between voice data packets received from the data network.
20. A communications system as recited in claim 16, wherein said monitoring means detects lost voice data packets.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for manufacturing a light-emitting device comprising:
removing a substrate from a semiconductor layer, the semiconductor layer being provided on a first main surface of the substrate, the semiconductor layer including a light-emitting layer, at least a top surface and side surfaces of the semiconductor layer being covered with a first insulating film, a first electrode portion electrically continuous to the semiconductor layer being provided, a second electrode portion electrically continuous to the semiconductor layer being provided, the first insulating film being covered with a second insulating film, the removing being performed by irradiating the semiconductor layer with laser light from a side of a second main surface of the substrate, the second main surface being opposite to the first main surface,
each of band-gap energy of the second insulating film and band-gap energy of the semiconductor layer being smaller than energy of the laser light.
2. The method according to claim 1, wherein at least a part of the portions of the first insulating film covering the side surfaces between the first main surface and the light-emitting layer is formed to have a smaller thickness than a wavelength of the laser light in a direction perpendicular to the side surfaces.
3. The method according to claim 2, wherein the wavelength of the laser light is 248 nm and the thickness of the part of the first insulating film is smaller than 248 nm.
4. The method according to claim 1, wherein the first insulating film contains silicon oxide.
5. The method according to claim 1, wherein band-gap energy of the first insulating film is smaller than the energy of the laser light.
6. The method according to claim 1, wherein the first insulating film contains silicon nitride.
7. The method according to claim 1, wherein the portions of the first insulating film covering the side surfaces of the semiconductor layer reach the first main surface of the substrate.
8. The method according to claim 1, wherein the second insulating film and the semiconductor layer absorb the laser light.
9. The method according to claim 1, wherein a portion of the first insulating film being in contact with the substrate is removed after forming the first insulating film and before throwing the laser light upon.
10. The method according to claim 1, wherein the laser light does not reach a depth position of the light-emitting layer within portions of the first insulating film covering the side surfaces of the semiconductor layer.
11. A light-emitting device comprising:
a semiconductor layer including a light-emitting layer;
a first electrode portion and a second electrode portion which are provided on a second main surface of the semiconductor layer, the second main surface being opposite to a first main surface of the semiconductor layer;
a first insulating film covering at least side surfaces of the semiconductor layer; and
a second insulating film covering the first insulating film,
a thickness of a part of the first insulating film being smaller than 248 nm,
the second insulating film and the semiconductor layer being made of materials which absorb a laser light having a wavelength longer than 248 nm.
12. The device according to claim 11, wherein at least a part of the portions of the first insulating film covering the side surfaces between the first main surface and the light-emitting layer has a smaller thickness than a wavelength of the laser light in a direction perpendicular to the side surfaces.
13. The device according to claim 11, wherein portions of the first insulating film that cover the side surfaces of the semiconductor layer suppress the laser light from reaching a depth position of the light-emitting layer from the first main surface side of the semiconductor layer.
14. The device according to claim 11, wherein the first insulating film contains silicon oxide.
15. The device according to claim 11, wherein the first insulating film is made of a material with band-gap energy smaller than the energy of the laser light.
16. The device according to claim 11, wherein the first insulating film contains silicon nitride.
17. The device according to claim 11, wherein the portions of the first insulating film covering the side surfaces of the semiconductor layer reach the first main surface of the substrate.
18. The device according to claim 11, further comprising:
the second insulating film covering the first insulating film;
a first interconnection piercing the second insulating film and electrically contact with the first electrode portion; and
a second interconnection piercing the second insulating film and electrically contact with the second electrode portion.
19. The device according to claim 18, further comprising:
a third insulating film provided on the second insulating film;
a first metal pillar piercing the third insulating film and electrically contact with the first interconnection; and
a second metal pillar piercing the third insulating film and electrically contact with the second interconnection.