High-brightness off-axis LCD projection lens system

The utility model discloses a high-brightness off-axis type LCD projection lens system which comprises a convex lens, a negative lens, a positive lens, a diaphragm and a Fresnel lens. The convex lens is a biconvex lens, the negative lens comprises a biconcave negative lens and an approximately equal-thickness aspheric negative lens, and the positive lens is a semilunar aspheric positive lens; a biconvex lens, a biconcave negative lens, a diaphragm, a semilunar aspherical positive lens, an aspherical negative lens with approximately equal thickness, a Fresnel lens and an LCD are sequentially arranged from a projection surface to the LCD, the convex lenses, the negative lens, the positive lens and the Fresnel lens are arranged and combined, and the optical axis of the system can pitch by +/-9.5 degrees, so that the 100% off-axis effect can be realized; the optical axis of the system is horizontally inclined by +/-5 degrees, so that the effect of 60% horizontal off-axis can be realized; as all the lenses are coa