Data Sheet
Product Specification 
Ver 1.2                                                                                            37 / 43 
9. Optical characteristics 
9-1) Specifications 
Measurements  are  made  with  that  the  illumination  is  under  an  angle  of  45  degrees,  the  detection  is  perpendicular  unless  otherwise 
specified. 
                                                                                                                                                                                          T=25℃ 
SYMBOL  PARAMETER  CONDITIONS  MIN  TYPE  MAX  UNIT  Note 
R  Reflectance  White  30  35  -  % 
Note 
9-1 
Gn  2Grey Level  -  -  DS+(WS-DS)xn(m-1)  -  L*  - 
CR  Contrast Ratio    indoor  8    -  -  - 
  Panel’s life    0℃~40℃    1000000 times     
Note 
9-2 
Panel 
Image Update 
Storage and 
transportation 
  Update the white screen       
Update Time  Operation   
Suggest update once every 
24 hours or at least 10 days 
to update again. 
WS: White state, DS: Dark state 
Gray state from Dark to White : DS、WS 
m: 2 
Note 9-1: Luminance meter: Eye – One Pro Spectrophotometer 
Note 9-2: Panel life will not guaranteed when work in temperature below 0 degree or above 40 degree. Each update interval time should be 
minimum at 180 seconds.   
9-2) Definition of contrast ratio 
The contrast ratio (CR) is the ratio between the reflectance in a full white area (R1) and the reflectance in a dark area (Rd)() : 
R1: white reflectance          Rd: dark reflectance 
CR = R1/Rd 
Display
Detector
Ring light
θ
. 
2.7" e-Paper (B)










