Flight Crew Air Transport Pilot (ATP)
Workload; Confusion; Situational Awareness; Distraction; Human-Machine Interface
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Clearance; Ground Incursion Taxiway
Flight Crew Requested ATC Assistance / Clarification; Flight Crew Became Reoriented
Airport; Equipment / Tooling
Cleared to taxi via C; B5; B; G; D to Runway 19L.  Once established on Taxiway B; First Officer (FO) advised he was heads down to load final numbers into FMC for takeoff while I was looking for signs marking Taxiway G.  I passed Taxiway G thinking it was B7; but realized my mistake as I could see no further angled taxiways to my right.  I stopped the aircraft to obtain an amended clearance from Ground Control; and was re-cleared to taxi via B; Z; and D.  This was my 13th trip into LAS this month; with most departures previously operating from Runway 1R.  Prior to gate departure on this flight; I briefed the hot spots and expected runway; but did not brief an expected taxi route as it is unpredictable due to construction.  Although I missed the turn; traffic was not a factor and at no time were we near a runway intersection or in danger of incurring on a runway.Contributing factors were poor or non-existent markings to indicate Taxiway G from Taxiway B; and difficulty in reading the 10-9 airport diagram on my iPad due to bright sunlight conditions.
A B737 Captain taxiing to Runway 19R on Taxiway B at LAS missed Taxiway G thinking it was B7. Reporter cited airport signage and relatively dim iPad in bright light as contributing factors.