brycewang-stanford/patent-analysis-guide

Patent Analysis Guide

A skill for conducting patent research, landscape analysis, and prior art searches. Covers patent database APIs, classification systems, citation network analysis, claim parsing, and technology trend mapping for intellectual property research.

Patent Data Sources

Major Patent Databases

| Database | Coverage | API | Cost | |----------|----------|-----|------| | USPTO PatentsView | US patents and applications | REST API, bulk download | Free | | EPO Open Patent Services | EP, WO, and 100+ offices | REST API (OPS) | Free (throttled) | | Google Patents | 120M+ documents worldwide | BigQuery (Google Patents Public) | Free (BigQuery costs) | | Lens.org | 130M+ patent records | REST API | Free for researchers | | WIPO PATENTSCOPE | PCT applications + national | REST API | Free |

Programmatic Patent Search

import requests
import xml.etree.ElementTree as ET

class EPOClient:
    """Client for the EPO Open Patent Services (OPS) API."""

    BASE_URL = "https://ops.epo.org/3.2/rest-services"

    def __init__(self, consumer_key: str, consumer_secret: str):
        self.token = self._authenticate(consumer_key, consumer_secret)

    def _authenticate(self, key: str, secret: str) -> str:
        import base64
        credentials = base64.b64encode(f"{key}:{secret}".encode()).decode()
        resp = requests.post(
            "https://ops.epo.org/3.2/auth/accesstoken",
            headers={"Authorization": f"Basic {credentials}"},
            data={"grant_type": "client_credentials"},
        )
        return resp.json()["access_token"]

    def search(self, cql_query: str, max_results: int = 25) -> list[dict]:
        """
        Search patents using CQL (Common Query Language).
        Example queries:
          ta="machine learning" AND cl="neural network"
          pa="university" AND pd>=2020
        """
        resp = requests.get(
            f"{self.BASE_URL}/published-data/search",
            headers={"Authorization": f"Bearer {self.token}",
                     "Accept": "application/json"},
            params={"q": cql_query, "Range": f"1-{max_results}"},
        )
        return resp.json()

Patent Classification Systems

Cooperative Patent Classification (CPC)

The CPC hierarchy has five levels: Section > Class > Subclass > Group > Subgroup.

Example: H04L 9/3247
  H       = Electricity (Section)
  H04     = Electric communication technique (Class)
  H04L    = Transmission of digital information (Subclass)
  H04L 9/ = Cryptographic mechanisms (Group)
  H04L 9/3247 = Digital signatures (Subgroup)

IPC to CPC Mapping

def parse_cpc_code(code: str) -> dict:
    """Parse a CPC classification code into its hierarchical components."""
    code = code.strip().replace(" ", "")
    return {
        "section": code[0],
        "class": code[:3],
        "subclass": code[:4],
        "group": code.split("/")[0] if "/" in code else code[:4],
        "subgroup": code if "/" in code else None,
        "full": code,
    }

# Technology domain mapping (top-level CPC sections)
CPC_SECTIONS = {
    "A": "Human Necessities",
    "B": "Performing Operations; Transporting",
    "C": "Chemistry; Metallurgy",
    "D": "Textiles; Paper",
    "E": "Fixed Constructions",
    "F": "Mechanical Engineering; Lighting; Heating",
    "G": "Physics",
    "H": "Electricity",
    "Y": "General Tagging of New Technological Developments",
}

Patent Landscape Analysis

Building a Patent Landscape

A patent landscape maps the technology and competitive environment in a domain:

import pandas as pd
import numpy as np
from collections import Counter

def patent_landscape_metrics(patents: pd.DataFrame) -> dict:
    """
    Compute patent landscape metrics from a patent dataset.
    Expected columns: patent_id, filing_date, grant_date,
    assignee, cpc_codes (list), claims_count, citations_received
    """
    # Filing trend (annual)
    patents["filing_year"] = pd.to_datetime(patents.filing_date).dt.year
    annual_filings = patents.groupby("filing_year").size()

    # Top assignees
    top_assignees = patents.assignee.value_counts().head(20)

    # Technology distribution (CPC subclass level)
    all_cpc = []
    for codes in patents.cpc_codes:
        all_cpc.extend([c[:4] for c in codes])
    cpc_distribution = Counter(all_cpc).most_common(20)

    # Citation impact
    citation_stats = patents.citations_received.describe()

    # Geographic distribution (from assignee country)
    geo_dist = patents.assignee_country.value_counts()

    return {
        "total_patents": len(patents),
        "annual_filings": annual_filings.to_dict(),
        "top_assignees": top_assignees.to_dict(),
        "technology_areas": cpc_distribution,
        "citation_stats": citation_stats.to_dict(),
        "geographic_distribution": geo_dist.head(10).to_dict(),
    }

Citation Network Analysis

import networkx as nx

def build_citation_network(patents: pd.DataFrame,
                            citations: pd.DataFrame) -> nx.DiGraph:
    """
    Build a patent citation network.
    citations: DataFrame with columns [citing_patent, cited_patent]
    """
    G = nx.DiGraph()

    # Add patent nodes with attributes
    for _, row in patents.iterrows():
        G.add_node(row.patent_id, assignee=row.assignee,
                   year=row.filing_year, cpc=row.cpc_codes[0][:4])

    # Add citation edges
    for _, row in citations.iterrows():
        if row.citing_patent in G and row.cited_patent in G:
            G.add_edge(row.citing_patent, row.cited_patent)

    return G

def identify_seminal_patents(G: nx.DiGraph, top_n: int = 20) -> list:
    """Find the most influential patents by various centrality measures."""
    in_degree = dict(G.in_degree())
    pagerank = nx.pagerank(G)

    # Combine metrics
    scores = {}
    for node in G.nodes():
        scores[node] = {
            "citations_received": in_degree[node],
            "pagerank": pagerank[node],
        }
    ranked = sorted(scores.items(), key=lambda x: x[1]["pagerank"], reverse=True)
    return ranked[:top_n]

Claim Analysis

Parsing Patent Claims

Patent claims define the legal scope of protection. Independent claims are the broadest; dependent claims narrow them:

def parse_claims(claims_text: str) -> list[dict]:
    """
    Parse patent claims text into structured claim objects.
    Identifies independent vs dependent claims and extracts dependencies.
    """
    # Split on claim numbers
    claim_pattern = re.compile(r"\n\s*(\d+)\.\s+", re.MULTILINE)
    parts = claim_pattern.split(claims_text)

    claims = []
    for i in range(1, len(parts), 2):
        claim_num = int(parts[i])
        claim_text = parts[i + 1].strip()

        # Detect dependency
        dep_match = re.match(
            r"(?:The|A)\s+\w+\s+(?:of|according to)\s+claim\s+(\d+)",
            claim_text, re.IGNORECASE
        )
        is_independent = dep_match is None
        depends_on = int(dep_match.group(1)) if dep_match else None

        claims.append({
            "number": claim_num,
            "text": claim_text,
            "independent": is_independent,
            "depends_on": depends_on,
            "word_count": len(claim_text.split()),
        })
    return claims

Prior Art Search Strategy

Systematic prior art search methodology:

1. Define the invention: Break the invention into key technical features
2. Keyword search: Use synonyms, broader terms, and technical variants
3. Classification search: Identify relevant CPC/IPC codes and search within them
4. Citation search: Forward and backward citation tracking from known relevant patents
5. Assignee search: Search patents from known competitors and research groups
6. Non-patent literature: Check academic papers, standards, product documentation

Tools and Resources

• PatentsView API: Free US patent data with assignee disambiguation
• Google Patents: Full-text search with CPC browsing and citation links
• Lens.org: Scholarly and patent search with linking between patents and papers
• Derwent Innovation: Commercial tool for comprehensive patent analytics
• PatSnap: AI-powered patent intelligence platform
• WIPO Pearl: Multilingual patent terminology database