One Case a Day | China: The Impact of Terminology Understanding on Priority Establishment - "Light-Emitting Element" Case (2023) Supreme People's Court Zhi Xing Zhong No. 338

Case Introduction

To determine whether priority is established, in addition to considering the time element, it is also necessary to examine whether the subject matter is the same and whether the earlier application is the "first application." In this case, the invalidation requester attempted to challenge priority from the perspective of the same subject matter, questioning the first application to negate priority, thereby achieving the goal of challenging novelty and inventiveness. Undoubtedly, this case is typical in examining whether superordinate and subordinate concepts constitute the same subject matter.

Another question worth pondering is: Why did the understanding of an important technical term become a point of attack for competitors to invalidate the patent? Moreover, it was interpreted twice by the Reexamination Board and the first-instance court in a manner unfavorable to the right holder, and it was not until the second instance that it finally returned to its originally expected interpretation?

Case Information

• Application Number: 2005800051125
• Invention Title: Light-Emitting Element and Lighting Device
• Invalidation Decision Information: No. 46706
• First-Instance Information: (2021) Jing 73 Xing Chu No. 1826
• Second-Instance Information: (2023) Supreme People's Court Zhi Xing Zhong No. 338
• Judgment Date: December 25, 2025

Controversial Focus

The relevant Claims 1-6 of the involved patent protect a light-emitting device containing a first fluorescent substance of a yttrium aluminum garnet (YAG) series phosphor, which emits at least one color of light among green, yellow-green, or yellow. At the same time, Claims 1-6 claim priority from the earlier application A (JP2004-041502).

The invalidation requester cited an earlier application B (Evidence 2: JP2003-394855), which predates A, as evidence. The technical scheme related to Claims 1-6 recorded therein differs only in that the fluorescent substance is a yellow-emitting (Y,Gd)3(Al,Ga)5O12:Ce.

The controversial focus of this case is: Whether the chemical formula (Y,Gd)3(Al,Ga)5O12:Ce in application B and the yttrium aluminum garnet series phosphor in application A belong to the same concept, in order to determine whether the corresponding subject matter was first recorded in application A, and further determine whether the priority of Claims 1-6 is established.

Views of the Parties

The challenged decision held: (Y,Gd)3(Al,Ga)5O12:Ce itself is a series of phosphors, not a certain or several related substances. Using this chemical formula to represent the yttrium aluminum garnet series phosphor is a common practice in this field, and the two belong to the same concept. Application B is the earlier application that first recorded the same subject matter as Claims 1-6, which means application A cannot become the priority basis for Claims 1-6 of the involved patent.

The patentee argued: The yttrium aluminum garnet series phosphor and (Y,Gd)3(Al,Ga)5O12:Ce are in a superordinate-subordinate concept relationship. When judging priority, superordinate and subordinate concepts do not belong to the same subject matter. Therefore, Evidence 2 cannot constitute the first application of this patent.

The first-instance court held: The yttrium aluminum garnet series phosphor essentially has narrow and broad concepts. Among yttrium aluminum garnet series phosphors, (Y,Gd)3(Al,Ga)5O12:Ce is the most technically stable and widely applied. Therefore, in a narrow sense, the yttrium aluminum garnet series phosphor can refer to its most representative (Y,Gd)3(Al,Ga)5O12:Ce. In a broad sense, the yttrium aluminum garnet series phosphor is a general term for various phosphors doped with different rare earth and/or impurity elements, including (Y,Gd)3(Al,Ga)5O12:Ce. Specifically for this patent, given that this patent's specification clearly records technical content such as "the cerium-activated yttrium aluminum garnet series phosphor represented by the chemical formula (Y,Gd)3(Al,Ga)5O12:Ce3+" and "white light-emitting diodes made from blue light-emitting diode elements and yttrium aluminum garnet series phosphors have a bluish-white characteristic due to insufficient red light," it can be concluded that the yttrium aluminum garnet series phosphor recorded in this patent adopts the narrow concept, specifically referring to (Y,Gd)3(Al,Ga)5O12:Ce.

Second-Instance Court

1. Article 29, Paragraph 1 of the Patent Law stipulates: "Where, within twelve months from the date on which any applicant first filed in a foreign country an application for a patent for invention or utility model, or within six months from the date on which any applicant first filed in a foreign country an application for a patent for design, he or it files in China an application for a patent for the same subject matter, he or it may enjoy a right of priority in accordance with any agreement concluded between the said foreign country and China, or in accordance with any international treaty to which both countries are party, or on the basis of the principle of mutual recognition of the right of priority."

2. Accordingly, for invention or utility model patents, determining whether priority is established requires focusing on examining three elements:

First, whether the earlier application serving as the basis for claiming priority and the later application claiming priority are for the same subject matter of invention or utility model;

Second, whether the earlier application is the "first application" filed by the applicant for the same subject matter of invention or utility model;

Third, whether the filing date of the later application is within 12 months of the filing date of the first earlier application.

3. Furthermore, only when the later application and the earlier application are identical in four aspects—technical field, technical problem solved, technical solution, and expected technical effect—can they be determined to belong to the same subject matter.

4. When verifying whether the earlier application and the later application belong to the same subject matter, the technical solution described in each claim of the later application should be analyzed and studied together with the entirety of the earlier application to determine whether the technical solution described in the claims of the later application is clearly recorded in the documents of the earlier application. Determining whether the later application is clearly recorded in the documents of the earlier application does not require the two to be completely consistent in wording or narrative method. However, the content defined by the claims of the later application should be directly and unambiguously derivable from the documents of the earlier application. If the earlier application only provides a general or vague description of a certain technical feature, and the technical features recorded in the claims of the later application include a detailed description or newly added content for this technical feature, to the extent that a person skilled in the art believes the technical solution cannot be directly and unambiguously derived from the earlier application, then the two should be determined not to belong to the same subject matter.

5. Claim 1 of this patent clearly records that the first fluorescent substance in the technical solution is a yttrium aluminum garnet series phosphor that emits at least one color of light among green, yellow-green, or yellow. A person skilled in the art knows that yttrium aluminum garnet series phosphors are a class of high-performance luminescent materials that use yttrium aluminum garnet (chemical formula Y3Al5O12, commonly abbreviated as YAG) as the crystal matrix. By doping different rare earth ions as activators, electron energy level transitions and energy conversion occur, thereby imparting luminescent properties. Pure yttrium aluminum garnet as the crystal matrix itself does not luminesce; its luminescent properties are entirely determined by the doped ions. Changing the type of doped ions or comprehensively adjusting the doping ratio of doped ions can adjust spectral characteristics and change the luminescent color. In the crystal structure of yttrium aluminum garnet (YAG), there are three cation sites: the Y site, the Al octahedral site, and the Al tetrahedral site. Common doping elements for the Y site include Gd, Tb, La, Lu, Sc, Ce, etc., and common doping elements for the Al site include Ga, Sc, etc. (Y,Gd)3(Al,Ga)5O12:Ce3+ is a common yttrium aluminum garnet series phosphor, but elements such as Tb3+, Ho3+, Mn2+, Pr3+ can also excite yttrium aluminum garnet to emit green, yellow-green, or yellow fluorescence. Therefore, based on the wording of Claim 1 of this patent, the yttrium aluminum garnet series phosphor that emits at least green, yellow-green, or yellow light is not limited to the phosphor represented by (Y,Gd)3(Al,Ga)5O12:Ce3+; the two define different scopes.

6. The specification of this patent states in the background section: "In recent years, white light-emitting diodes composed of blue light-emitting diode elements and luminescent phosphors that absorb blue light and emit yellow light have been extensively researched." It later mentions: "The most commonly used phosphor among them is the cerium-activated yttrium aluminum garnet series phosphor represented by the chemical formula (Y,Gd)3(Al,Ga)5O12:Ce3+. However, white light-emitting diodes made from blue light-emitting diode elements and yttrium aluminum garnet series phosphors have a bluish-white characteristic due to insufficient red components." Apart from this section, the specification does not mention the expression (Y,Gd)3(Al,Ga)5O12:Ce3+ elsewhere, but consistently refers to the yttrium aluminum garnet series phosphor. Additionally, based on information recorded in the invention content section of this patent's specification, such as "the first fluorescent substance that emits at least one color of light among green, yellow-green, or yellow" and "the first fluorescent substance is a phosphor powder with a main emission wavelength of 495-585 nm," it cannot exclude other types of yttrium aluminum garnet series phosphors besides (Y,Gd)3(Al,Ga)5O12:Ce3+ from meeting the aforementioned wavelength requirements. Therefore, after reading the entire specification of this patent, a person skilled in the art, based on their general technical knowledge in the field and usual textual interpretation, should understand (Y,Gd)3(Al,Ga)5O12:Ce3+ as belonging only to the most commonly used category of substances among yttrium aluminum garnet series phosphors. They cannot confirm that all occurrences of the yttrium aluminum garnet series phosphor in the specification specifically refer to the category of substances represented by (Y,Gd)3(Al,Ga)5O12:Ce3+.

7. The requester argued that based on the wavelength range of "commercially available yttrium aluminum garnet series phosphors for existing CRT green phosphors" recorded on page 8 of this patent's specification under "Preparation of Green Phosphors," combined with the excitation and emission spectra shown in the specification drawings, the yttrium aluminum garnet series phosphor recorded in this patent can be uniquely limited to the category of substances represented by (Y,Gd)3(Al,Ga)5O12:Ce3+, excluding situations such as yttrium aluminum garnet series phosphors activated by Tb3+ and other elements. However, the content recorded in the above specification is only relevant technical information of specific embodiments and cannot be used to limit the protection scope of the claims.

8. In summary, the yttrium aluminum garnet series phosphor defined in Claim 1 of this patent, which emits at least one color of light among green, yellow-green, or yellow, is different from the content covered by the yellow phosphor (Y,Gd)3(Al,Ga)5O12:Ce3+ recorded in Evidence 2. Claim 1 of this patent and Evidence 2 do not belong to patent applications for the same subject matter.

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