Obviousness

Obviousness Analysis under 35 U.S.C. § 103 for US Patent 11,533,794

An analysis under 35 U.S.C. § 103 evaluates whether the claimed invention would have been obvious to a person having ordinary skill in the art (POSITA) at the time of the invention, considering prior art references and motivations to combine them. The present patent, US 11,533,794, focuses on a resistive bypass circuit for series lighting circuits, particularly emphasizing low-wattage LED light sources and continuous (100% duty cycle) operation of the bypass resistor without dangerous heat.

The patent itself provides crucial information regarding the state of the art and the problems it seeks to overcome, which implicitly reveals motivations for a POSITA to combine existing technologies.

Prior Art References and Disclosures:

1. Fisherman, U.S. Pat. No. 2,760,120: This patent is explicitly cited as prior art and describes a series circuit for a light set with individual incandescent flasher or twinkle bulbs that include a bypass resistor connected in parallel with the bulb element. [Description, "BACKGROUND OF THE INVENTION" section, "Specifically, Fisherman, U.S. Pat. No. 2,760,120 discloses a series circuit for a light set with individual incandescent flasher or twinkle bulbs that include a bypass resistor in parallel with the bulb element." paragraph].
   • Key Limitation of Fisherman (as described by US 11,533,794): The patent states that Fisherman's operation is "limited to a set with a bulb that flashes on and off, a duty cycle of less than 100%." [Description, "BACKGROUND OF THE INVENTION" section, "The operation of the Fisherman light set is limited to a set with a bulb that flashes on and off, a duty cycle of less than 100%." paragraph]. Critically, the patent asserts that "The Fisherman device cannot be applied to a set wherein a bulb is burnt out, removed, or loose (and not conducting) to continue to illuminate the remaining bulbs in the circuit" because "the bypass resistor is continually conducting and the temperatures generated on any bypass resistor of practical size... will far exceed ignition temperatures of near by materials." [Description, "BACKGROUND OF THE INVENTION" section, "The Fisherman device cannot be applied to a set wherein a bulb is burnt out, removed, or loose (and not conducting) to continue to illuminate the remaining bulbs in the circuit." paragraph]. Fisherman used high-energy bulbs (2 watts). [Description, "BACKGROUND OF THE INVENTION" section, "Further, the Fisherman bulb is a high energy bulb, being 8 volt and ¼ amp, for a power consumption of 2 watts." paragraph].
2. General Knowledge of LEDs as Low-Energy Light Sources: The patent acknowledges "The current movement towards low energy incandescent bulbs, LEDs, and other energy saving light sources" [Description, "SUMMARY OF THE INVENTION" section, "The embodiment of this device is to provide a low cost resistive bypass element for series connected light sources." paragraph]. This indicates that LEDs were a known and actively adopted technology for reducing power consumption in lighting applications.
3. Known LED Flashing/Twinkling and Color-Changing Technologies: The patent describes "semiconductor light sources, such as light emitting diodes (LEDs), to provide a twinkling affect, by utilizing LED packages that incorporate integrated circuits (ICs) or other types of electronic circuits that control the flashing rate of the light source" as an object of the invention. [Description, "SUMMARY OF THE INVENTION" section, "Another object of the present invention is to provide the ability to allow for semiconductor light sources, such as light emitting diodes (LEDs), to provide a twinkling affect..." paragraph]. Similarly, it refers to LEDs providing "color changing characteristics by utilizing LED packages that incorporate two or more LED chips, and an IC, or other electronic circuit, that controls each LED chip in the LED package independently" as "Yet another object of the present invention." [Description, "SUMMARY OF THE INVENTION" section, "Yet another object of the present invention is to provide the ability to allow for semiconductor light sources, such as LEDs, to provide color changing characteristics..." paragraph]. These statements confirm that such LED functionalities, often controlled by ICs, were known in the art.

Obviousness Arguments for Independent Claims:

Independent Claim 1: Resistive bypass circuit for serially connected LED light sources with an always-conducting bypass resistor.

• Combination: Fisherman (U.S. Pat. No. 2,760,120) + General knowledge of low-energy LEDs.
• Rationale: Fisherman clearly teaches the core concept of a bypass resistor connected in parallel with a light source in a series circuit to maintain continuity. [Description, "BACKGROUND OF THE INVENTION" section, "Specifically, Fisherman, U.S. Pat. No. 2,760,120 discloses a series circuit..." paragraph]. The primary limitation of Fisherman, as identified by US 11,533,794, was the dangerous heat generated by the bypass resistor if it were to conduct continuously (100% duty cycle) with high-wattage incandescent bulbs. [Description, "BACKGROUND OF THE INVENTION" section, "The Fisherman device cannot be applied to a set wherein a bulb is burnt out..." paragraph].
  A POSITA, aware of this known problem with high-wattage bulbs and the concurrent trend towards "low energy incandescent bulbs, LEDs, and other energy saving light sources," would have a clear motivation to substitute the high-wattage incandescent bulbs of Fisherman with known low-energy LED light sources. [Description, "SUMMARY OF THE INVENTION" section, "The current movement towards low energy incandescent bulbs, LEDs, and other energy saving light sources allows for a simple resistor to be utilized without creating the heating issues previously faced if such a device was attempted." paragraph]. This substitution would predictably resolve the overheating issue, allowing the bypass resistor to operate continuously (100% duty cycle) without reaching dangerous temperatures, as the lower current draw of LEDs leads to significantly less heat generation in the bypass resistor. The patent explicitly states that "Now with these low power consuming lighting sources, a resistive bypass element becomes the forefront of products, providing a low-cost bypass circuit." [Description, "SUMMARY OF THE INVENTION" section, "The embodiment of this device is to provide a low cost resistive bypass element for series connected light sources." paragraph]. Therefore, combining Fisherman's bypass principle with low-power LEDs to achieve continuous bypass operation would have been obvious.

Independent Claim 9: Resistive bypass circuit of Claim 1 further including an LED flashing light source causing the entire circuit to flash.

• Combination: Obvious combination for Claim 1 + Known LED flashing/twinkling technology + Known master flashing circuits.
• Rationale: Fisherman already discloses the use of "flasher or twinkle bulbs" in a series circuit. [Description, "BACKGROUND OF THE INVENTION" section, "Specifically, Fisherman, U.S. Pat. No. 2,760,120 discloses a series circuit..." paragraph]. The concept of making an entire light circuit flash is also generally known in the art, often achieved by a "master" flasher. The patent itself mentions the use of "one or more incandescent light sources, each with a flashing device, but without an associated bypass element in parallel, can be located in the lighting circuit in order to flash all the remaining light sources in the circuit." [Description, "SUMMARY OF THE INVENTION" section, "In yet another embodiment of the invention, one or more incandescent light sources..." paragraph]. Given the obviousness of using LEDs with the bypass resistor (as per Claim 1), and the widespread knowledge of LED flashing circuits (including those using ICs to control flashing rates), a POSITA would find it obvious to integrate an LED flashing light source with a circuit designed to flash the entire string. This is merely applying a known decorative effect (flashing) to a known light source (LED) within a known circuit configuration (series with bypass).

Independent Claim 10: Resistive bypass circuit of Claim 1 where the bypass resistor's resistance is equal to or greater than the inherent resistance of the light source.

• Combination: Obvious combination for Claim 1 + Routine electrical design considerations.
• Rationale: Once a POSITA has arrived at the series LED circuit with parallel bypass resistors (as made obvious for Claim 1), the selection of the bypass resistor's value is a routine design choice. The patent itself provides a clear motivation for this specific resistance relationship: "the resistor bypass set 10 of the present invention operates such that every bulb failure, places a higher resistance into the set than the bulb it replaces, causing the remaining bulbs to proportionally dim, causing them to increase their life, and to run cooler." [Description, "DETAILED DESCRIPTION OF THE DRAWINGS" section, "The resistor bypass set 10 also has the advantage of being a safer set than the standard mini light sets..." paragraph]. A POSITA, seeking to achieve these desirable effects—such as extending the life of the remaining LEDs, ensuring cooler operation, or maintaining a specific aesthetic (e.g., proportional dimming vs. constant brightness)—would be predictably motivated to select a bypass resistor with a resistance equal to or greater than that of the bypassed LED light source. This is a straightforward engineering optimization based on known circuit behavior.

Independent Claim 15: Method of bypassing an LED light source with a bypass resistor having specific characteristics (resistance >= LED resistance, ability to carry all current, 100% duty cycle operation).

• Combination: Fisherman (U.S. Pat. No. 2,760,120) + General knowledge of low-energy LEDs + Routine electrical design practices.
• Rationale: Fisherman teaches the fundamental step of "inserting said bypass resistor in parallel with said at least one LED light source" (though with incandescent bulbs). [Description, "BACKGROUND OF THE INVENTION" section, "Specifically, Fisherman, U.S. Pat. No. 2,760,120 discloses a series circuit..." paragraph]. The selection steps for the bypass resistor's characteristics are directly motivated by known problems and solutions:
  • "ability to operate at 100% duty cycle": This addresses the explicit limitation of Fisherman (where 100% duty cycle operation led to overheating). As discussed for Claim 1, using low-energy LEDs, known in the art, would predictably enable this. [Description, "SUMMARY OF THE INVENTION" section, "The current movement towards low energy incandescent bulbs, LEDs, and other energy saving light sources allows for a simple resistor to be utilized without creating the heating issues previously faced if such a device was attempted." paragraph].
  • "ability to carry all of the current in the light string": This is an inherent functional requirement for any bypass resistor in such a circuit, a basic principle of circuit design known to any POSITA.
  • "a resistance greater than or equal to the predetermined resistance of said LED light source": As explained for Claim 10, this is a predictable design choice motivated by the desired outcome of causing proportional dimming, increased life, and cooler operation of the remaining lights upon failure. [Description, "DETAILED DESCRIPTION OF THE DRAWINGS" section, "The resistor bypass set 10 also has the advantage of being a safer set than the standard mini light sets..." paragraph].
    Therefore, the method claim describes a series of steps that would be obvious to a POSITA seeking to combine known elements (Fisherman's bypass, LEDs) to achieve a predictable outcome (reliable, continuously operating series lighting with desired post-failure behavior).

Conclusion on Obviousness:

The independent claims of US 11,533,794, when analyzed against the explicitly cited prior art (Fisherman, U.S. Pat. No. 2,760,120) and the general knowledge acknowledged within the patent document itself (e.g., "current movement towards low energy... LEDs," known LED flashing/color-changing technologies), appear to be obvious. The patent itself identifies the key problem (overheating bypass resistor in prior art) and the general solution (using low-energy light sources like LEDs), thereby providing a clear motivation for a POSITA to combine these known elements to arrive at the claimed invention with predictable results. The specific design choices regarding resistor values and the incorporation of known LED functionalities would also be obvious to a POSITA.