1 Plane mirrors, convex lens and concave lens.

2 The relation between the focal length of a concave lens and its reflective image properties is analysed and deduced.

3 The invention provides a method with a concave lens focus as a welding heat source and a welding device thereof.

4 For medium and large optical concave lens into a set or single piece of fine grinding process.

5 A concave lens causes rays to diverge as though they are coming from a focal point.

6 We fabricated a large computer-generated holography on a concave lens surface to test the convex secondary mirrors surface.

7 For the radius of curvature than the concave lens in the 50mm and 450mm diameter below the plane mirror grinding and polishing.

8 Most myopic children can be fitted with glasses with concave lenses which will bring their vision to normal.

9 Some are flared - that is, thicker at the rim than the center, like a concave lens.

10 An approach is proposed, which emphasizes the importance of concave lens which can scatter the laser and make it an ideal signal source to be captured by the CCD lens.

11 But it needs to develop and perfect continually in the process of dealing with series of problems reflected by the concave lens of practice.

12 This article introduces a method of measuring the radial of a concave lens with laser, grating and vemier caliper.

13 Firstly, a telescope system is made up with a concave lens and a long-focus convex lens, by which the angle of the parallel beam from the collimator can be change.