The half of the wavelength corresponding to the λ1 970nm bandpass filter bandpass maximum transmittance of the glass and the difference λ2 (λ1-λ1) nm is called a half-width. Short-wave cut-off wavelength is in the short wavelength side of the peak, the transmittance is equal to zero wavelength. Long wave length cutoff glass in the long-wave side of the peak transmission wavelength than or equal to zero, and some species, in the long-wave side of the glass transmittance reach zero, places certain wavelength transmittance representation. Bandpass glass DTB Pinyin first letter to name, the transmittance value of the maximum wavelength position as their number. Optical indicators: center wavelength: 970 ± 2nm transmittance: T> 91% half-bandwidth: 42nm cutoff wavelength 740nm-940nm 1020nm-1080nm cutoff rate: T <0.1% Features: Imported thin optical glass, through high altitude finish Well, small thickness tolerance, flatness good optical properties such as; using imported equipment ion sputtering coating technology, with high labor solid film, spectral uniformity, strong center wave stable performance; Application: red laser container gauges, bar code scanners; desktop barcode scanners, laser measuring instrument, red LD pumped laser, red laser diode, IR range finder, a fingerprint identification device.