Canon Patent Application: Canon MT-26EX Flash Patent

In what appears to be a detailed patent application, it appears that Canon is looking to augment the Canon MT-24EX Flash system with wireless communication for 600-RT support.

The patent application is a little hard to follow, but the important thing is that wireless communication is radio transmission and lightwave pulse communication is the older light emitting communication of the older flash E-TTL flash system.

Edit: As it was so wisely pointed out to me, it slipped right by me that Canon already did do this with the MT-26EX in 2017.  This is most likely the patent for the technology in that flash, so read it if you are curious.

The present invention relates to the lighting system which can perform a wireless communication using the electric wave used at the time of static image photographing, etc. 
[Background of the Invention] 
[0002] 
A Patent document 1 has disclosed the wireless multi-light system constituted by the slave stroboscope which receives the optical pulse signal from a master stroboscope, and emits light in wireless without being connected to the master stroboscope and camera which were built in or connected to the camera. However, communication using an optical pulse signal is lost with outdoor daylight, when using it outdoors in the daytime, an optical pulse signal does not reach a slave stroboscope, but it may start a luminescence omission. Since wavelength of an optical pulse signal is short, its directivity needs to be strong, and it needs to carry out the right opposite of a master stroboscope transmission section and the slave stroboscope receive section to some extent. For this reason, if a shelter exists between a master stroboscope and a slave stroboscope, it may be unable to communicate, and setting is difficult and inconvenient. 
[0003] 
Then, the wireless multi-light system which uses not an optical pulse signal but a radio wave signal is proposed. Hereinafter, especially, as long as there is no notice, the thing of a wireless communication using an optical pulse signal is expressed as lightwave pulse communication, and the thing of a wireless communication using an electric wave is expressed as a wireless communication. 
[0004] 
A Patent document 2 has disclosed the stroboscope for close-up photography (strobe device) with which the control part and the light-emitting part are separated, and wired connection of a control part and the light-emitting part was carried out by the curled cord etc. In the strobe device of a Patent document 2, a control part can be attached with the accessory shoe of a camera, and a light-emitting part can be attached at the tip of a lens via the attachment of ring shape. When it is going to arrange the wireless module board for wireless communications to the strobe device of such composition, it is possible to provide a wireless module board to a light-emitting part. However, if a wireless module board is included in a light-emitting part, it is necessary to add the harness for electrically connecting a wireless module board and the control board provided by the control part in a curled cord. If the signal wires in a curled cord increase in number, the diameter of a curled cord may become thick and may affect the operability of a light-emitting part. The line where the voltage close to 300V voltage-increased by the main capacitor of the light-emitting part is applied to a curled cord exists, and the noise emitted from the line may take the signal wire from a wireless module, and may induce malfunction. Then, the wireless module board can consider providing to a control part. 

Japan Patent Application 2018-120093