Laurent, I have found the source of the problem: it's the package poppler-data!!! It contains support for CJK fonts.
Without poppler-data installed, pdffonts Lens_HF125HA-1B.pdf returns:
name type emb sub uni object ID
------------------------------------ ----------------- --- --- --- ---------
Error: Missing language pack for 'Adobe-Japan1' mapping
Error: Missing language pack for 'Adobe-Japan1' mapping
Error: Missing language pack for 'Adobe-Japan1' mapping
Error: Missing language pack for 'Adobe-Japan1' mapping
Helvetica-Bold Type 1 no no no 26 0
With poppler-data installed, pdffonts Lens_HF125HA-1B.pdf returns:
name type emb sub uni object ID
------------------------------------ ----------------- --- --- --- ---------
Helvetica-Bold Type 1 no no no 26 0
FutoGoB101-Bold-Identity-H CID Type 0C yes no no 11 0
ShinGo-Medium-Identity-H CID Type 0C yes no no 12 0
GothicBBB-Medium-Identity-H CID Type 0C yes no no 10 0
ShinGo-Bold-Identity-H CID Type 0C yes no no 24 0
So I was wrong before, the problem is not Helvetica that's not embedded, it's that poppler cannot render the embedded fonts without poppler-data!
Laurent, I have found the source of the problem: it's the package poppler-data!!! It contains support for CJK fonts.
Without poppler-data installed, pdffonts Lens_HF125HA-1B.pdf returns: ------- ------- ------- ------- - ----------------- --- --- --- ---------
name type emb sub uni object ID
-------
Error: Missing language pack for 'Adobe-Japan1' mapping
Error: Missing language pack for 'Adobe-Japan1' mapping
Error: Missing language pack for 'Adobe-Japan1' mapping
Error: Missing language pack for 'Adobe-Japan1' mapping
Helvetica-Bold Type 1 no no no 26 0
With poppler-data installed, pdffonts Lens_HF125HA-1B.pdf returns: ------- ------- ------- ------- - ----------------- --- --- --- --------- Bold-Identity- H CID Type 0C yes no no 11 0 Medium- Identity- H CID Type 0C yes no no 12 0 Medium- Identity- H CID Type 0C yes no no 10 0 Bold-Identity- H CID Type 0C yes no no 24 0
name type emb sub uni object ID
-------
Helvetica-Bold Type 1 no no no 26 0
FutoGoB101-
ShinGo-
GothicBBB-
ShinGo-
So I was wrong before, the problem is not Helvetica that's not embedded, it's that poppler cannot render the embedded fonts without poppler-data!
Please verify this solution