Abstract
The present invention provides an inexpensive cathode ray tube envelope which suffers considerably diminished glass browning in comparison with traditional cathode ray tube envelopes. The method of reducing glass browning in cathode ray tubes, and a suitable glass composite and glass composition are also provided. The cathode ray tube envelope of the present invention includes a screen which has an inner and an outer glass layers. The inner layer is made of lead-free glass whereas the outer layer is made of lead-containing glass. In the operational cathode ray tube of the present invention, the electron beams emitted therein, are absorbed by the inner layer without substantial browning, since the inner layer does not contain material that cause browning, and do not penetrate to the lead-containing outer layer. At the same time, the X-rays produced in the cathode ray tube are effectively and efficiently blocked by the lead-containing outer layer. The result is both significant reduction in glass browning and effective X-ray protection.