How to make changes to the biblatex patent driver (date not displaying)

Question

I am using biblatex and I would like to change the format of the type patent.

I had a look at the driver and to begin with I am wondering why the date is in the driver, but is not displayed in an entry. Also I tried to change the order of holder and author, but this is somehow not working. Is there a good manual explaining how to adjust the drivers?

Attached you find a minimal working example with the way a patent is presented right now and with an example I would like to have it.

Thanks for the help.

\RequirePackage{filecontents}
\begin{filecontents}{\jobname.bib}
@Patent{Murata2007,
    author = {Murata, Yutaka and Ogawa, Masao},
    title  = {Sitzkonstruktion für ein Motorrad},
    number = {DE602004003996T2},
    year   = {2007},
    date   = {2007-05-10},
    holder = {{HONDA MOTOR LTD.}},
    type   = {patentde},
}
\end{filecontents}


\documentclass[a4paper,11pt,DIV=calc, titlepage]{scrartcl} 

\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[ngerman]{babel}
\usepackage[%
  left=4cm,right=2.5cm,top=2.0cm,bottom=2cm,
  includeheadfoot
]{geometry} 

\usepackage[babel, german=quotes]{csquotes}
\usepackage[%
  style=authoryear-ibid,
  natbib=true, 
  maxbibnames=3,
  maxcitenames=2,
  uniquelist=false, 
  uniquename=false, 
  backend=biber
]{biblatex}
\addbibresource{\jobname.bib}

\usepackage[hidelinks]{hyperref}


\renewcommand*{\mkbibnamefamily}[1]{\textsc{#1}} %Zitat und Lit in Kapitätlchen

\DefineBibliographyStrings{ngerman}{ % et al instead of "und" with 3 or more authors
   andothers = {{et\,al\adddot}},  }

\renewcommand{\multinamedelim}{\addsemicolon\space} % <=================
%\renewcommand{\finalnamedelim}{\multinamedelim} % <=====================

\DeclareNameAlias{sortname}{family-given} %Sort: Last name, first name
\DeclareNameAlias{default}{family-given}  %Sort: Last name, first name

\DeclareFieldFormat[%
  article,inbook,incollection,inproceedings,patent,thesis,unpublished,
  report, norm, phdthesis, other, misc
]{citetitle}{#1} %Remove quotation marks from title
\DeclareFieldFormat[%
  article,inbook,incollection,inproceedings,patent,thesis,unpublished,
  report, norm, phdthesis, other, misc
]{title}{#1} %Remove quotation marks from title


%Driver for patent:
%------------
\DeclareBibliographyDriver{patent}{%
    \usebibmacro{bibindex}%
    \usebibmacro{begentry}%
    \usebibmacro{author}%
    \setunit{\printdelim{nametitledelim}}\newblock
    \usebibmacro{title}%
    \newunit
    \printlist{language}%
    \newunit\newblock
    \usebibmacro{byauthor}%
    \newunit\newblock
    \printfield{type}%
    \setunit*{\addspace}%
    \printfield{number}%
    \iflistundef{location}
    {}
    {\setunit*{\addspace}%
        \printtext[parens]{%
            \printlist[][-\value{listtotal}]{location}}}%
    \newunit\newblock
    \usebibmacro{byholder}%
    \newunit\newblock
    \printfield{note}%
    \newunit\newblock
    \usebibmacro{date}% The date is here, but it is not displayed
    \newunit\newblock
    \usebibmacro{doi+eprint+url}%
    \newunit\newblock
    \usebibmacro{addendum+pubstate}%
    \setunit{\bibpagerefpunct}\newblock
    \usebibmacro{pageref}%
    \newunit\newblock
    \iftoggle{bbx:related}
    {\usebibmacro{related:init}%
        \usebibmacro{related}}
    {}%
    \usebibmacro{finentry}}
%--------------

\DeclareCiteCommand{\fullcite}
  {\usebibmacro{prenote}}
  {\usedriver
     {\DeclareNameAlias{sortname}{default}}
     {\thefield{entrytype}}}
  {\multicitedelim}
  {\usebibmacro{postnote}\adddot} % <===================================

%Fullcite change: Write out all authors up to 3
\preto\fullcite{\AtNextCite{\defcounter{maxnames}{3}}}


\begin{document}
The patent using \textbackslash fullcite and in the bibliography should look like this:\\

HONDA MOTOR LTD. (2007). Sitzkonstruktion für ein Motorrad. Erfinder: Murata, Yutaka \& Ogawa Masao. Dt. Pat. DE602004003996T2. Date published: 10.05.2007\\


Fullcite:\\
\fullcite{Murata2007}\\\\

\begingroup
\phantomsection\addcontentsline{toc}{section}{Literaturverzeichnis} 
\printbibliography[title={Literaturverzeichnis}]
\endgroup
\end{document}

Answer 1

You are using a style of the authoryear family, that family of styles provides a style option called mergedate. This option is not documented extensively in the biblatex manual, where it is only mentioned in passing. you will find a more explicit explanation in the style example 51-style-authoryear-ibid. The default setting is mergedate=compact and with versions 3.7 of biblatex that yields the output you get (the output is in fact inconsistent with the with earlier versions and the documented behaviour, this will be addressed in biblatex 3.8 where the mergedate option was overhauled and made ready for the new date features). mergedate=compact redefines the bibmacro date to print nothing, this is why even with an explicit call to that macro you get no date output.

You seem to want what amounts to mergedate=basic (or mergedate=minimum). So this is what I'll use.

The other changes are a bit more involved. The 'primary names' attached to a @patent are normally the authors and not the holder. So to use the holder as primary name we need to do a lot of high level redefinitions. We need to change sorting to sort by holder and not author, labelname to consider the holder, etc.

\RequirePackage{filecontents}
\begin{filecontents}{\jobname.bib}
@Patent{Murata2007,
    author = {Murata, Yutaka and Ogawa, Masao},
    title  = {Sitzkonstruktion für ein Motorrad},
    number = {DE602004003996T2},
    date   = {2007-05-10},
    holder = {{HONDA MOTOR LTD.}},
    type   = {patentde},
}
@Patent{Murata2008,
    author = {Awa, Masao and Murata, Yutaka},
    title  = {Sitzkonstruktion für ein Motorrad},
    number = {DE60wsetesewettew2},
    date   = {2008-05-10},
    holder = {{HONDA MOTOR LTD.}},
    type   = {patentde},
}
\end{filecontents}


\documentclass[a4paper,11pt,DIV=calc, titlepage, bibtotoc]{scrartcl} 

\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[ngerman]{babel}
\usepackage[%
  left=4cm,right=2.5cm,top=2.0cm,bottom=2cm,
  includeheadfoot
]{geometry} 

\usepackage[babel, german=quotes]{csquotes}
\usepackage[%
  style=authoryear-ibid,
  mergedate=basic,
  natbib=true, 
  maxbibnames=3,
  maxcitenames=2,
  uniquelist=false, 
  uniquename=false, 
  backend=biber
]{biblatex}
\addbibresource{\jobname.bib}
\addbibresource{biblatex-examples.bib}

\usepackage[hidelinks]{hyperref}


\renewcommand*{\mkbibnamefamily}[1]{\textsc{#1}}

\DefineBibliographyStrings{ngerman}{
  andothers = {{et\,al\adddot}},
}

\renewcommand{\multinamedelim}{\addsemicolon\space}
%\renewcommand{\finalnamedelim}{\multinamedelim}

\DeclareNameAlias{sortname}{family-given}
\DeclareNameAlias{default}{family-given}

\DeclareFieldFormat[%
  article,inbook,incollection,inproceedings,patent,thesis,unpublished,
  report, norm, phdthesis, other, misc
]{citetitle}{#1}
\DeclareFieldFormat[%
  article,inbook,incollection,inproceedings,patent,thesis,unpublished,
  report, norm, phdthesis, other, misc
]{title}{#1}

\DeclareSortingScheme{nyt}{
  \sort{
    \field{presort}
  }
  \sort[final]{
    \field{sortkey}
  }
  \sort{
    \field{sortname}
    \field{holder}
    \field{author}
    \field{editor}
    \field{translator}
    \field{sorttitle}
    \field{title}
  }
  \sort{
    \field{sortyear}
    \field{year}
  }
  \sort{
    \field{sorttitle}
    \field{title}
  }
  \sort{
    \field{volume}
    \literal{0}
  }
}


\NewBibliographyString{inventor}
\NewBibliographyString{inventors}
\DefineBibliographyStrings{german}{%
  inventor = {Erfinder},
  inventors = {Erfinder},
}

\newbibmacro*{inventor}{%
  \ifnameundef{author}
    {}
    {\ifnumgreater{\value{author}}{1}
       {\bibstring{inventors}}
        {\bibstring{inventor}}%
     \setunit{\addcolon\space}%
     \printnames{author}}}

\makeatletter
\DeclareLabelname[patent]{%
  \field{holder}
  \field{shortauthor}
  \field{author}
  \field{shorteditor}
  \field{editor}
  \field{translator}
}

\newbibmacro{holder}{%
  \ifnameundef{holder}
    {\global\undef\bbx@lasthash}
    {\usebibmacro{bbx:dashcheck}
       {\bibnamedash}
       {\usebibmacro{bbx:savehash}%
         \printnames{holder}
      \setunit{\printdelim{nameyeardelim}}}}%
  \usebibmacro{date+extrayear}%
}

\DeclareBibliographyDriver{patent}{%
    \usebibmacro{bibindex}%
    \usebibmacro{begentry}%
    \usebibmacro{holder}%
    \setunit{\printdelim{nametitledelim}}\newblock
    \usebibmacro{title}%
    \newunit
    \printlist{language}%
    \newunit\newblock
    \usebibmacro{inventor}%
    \newunit\newblock
    \printfield{type}%
    \setunit*{\addspace}%
    \printfield{number}%
    \iflistundef{location}
    {}
    {\setunit*{\addspace}%
        \printtext[parens]{%
            \printlist[][-\value{listtotal}]{location}}}%
    \newunit\newblock
    \printfield{note}%
    \newunit\newblock
    \usebibmacro{date}%
    \newunit\newblock
    \usebibmacro{doi+eprint+url}%
    \newunit\newblock
    \usebibmacro{addendum+pubstate}%
    \setunit{\bibpagerefpunct}\newblock
    \usebibmacro{pageref}%
    \newunit\newblock
    \iftoggle{bbx:related}
    {\usebibmacro{related:init}%
        \usebibmacro{related}}
    {}%
    \usebibmacro{finentry}}

\DeclareCiteCommand{\fullcite}
  {\usebibmacro{prenote}}
  {\usedriver
     {\defcounter{maxnames}{\blx@maxbibnames}}
     {\thefield{entrytype}}}
  {\multicitedelim}
  {\usebibmacro{postnote}\addperiod}
\makeatother


\begin{document}
\tableofcontents

The patent using \textbackslash fullcite and in the bibliography should look like this:\\

HONDA MOTOR LTD. (2007). Sitzkonstruktion für ein Motorrad. Erfinder: Murata, Yutaka \& Ogawa Masao. Dt. Pat. DE602004003996T2. Date published: 10.05.2007\\


Fullcite:\\
\fullcite{Murata2007}

\cite{sigfridsson,knuth:ct:a}
\cite{Murata2007,Murata2008}

\printbibliography[title={Literaturverzeichnis}]
\end{document}