Dichroic mirror and projection-type display unit
On a transparent substrate, a first alternating periodic layer including low-refractive-index layers and high-refractive-index layers, a second alternating periodic layer including the low-refractive-index layers or the high-refractive-index layers and intermediate-refractive-index layers, and a thi...
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| Main Author | |
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| Format | Patent |
| Language | English |
| Published |
23.01.2007
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| Online Access | Get full text |
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| Summary: | On a transparent substrate, a first alternating periodic layer including low-refractive-index layers and high-refractive-index layers, a second alternating periodic layer including the low-refractive-index layers or the high-refractive-index layers and intermediate-refractive-index layers, and a third alternating periodic layer including the low-refractive-index layers and the high-refractive-index layers are provided in this order. The refractive index of the intermediate-refractive-index layers is higher than that of the low-refractive-index layers and lower than that of the high-refractive-index layers. Furthermore, the intermediate-refractive-index layers contain materials for the low-refractive-index layers and the high-refractive-index layers. A dichroic mirror thus configured has a narrow color separating band between a transmission wavelength band and a reflection wavelength band, and therefore has a satisfactory color separating efficiency. Accordingly, a projection-type display unit using the dichroic mirror provides satisfactory color reproduction while retaining a high spectrum utilization efficiency. |
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