Electrostatic latent image measuring device

1. An electrostatic latent image measuring device comprising:

a charged particle optical system which irradiates an electron beam and charges a photoconductor sample;

an exposure optical system which forms an electrostatic latent image on a surface of the photoconductor sample; and

a scanning unit which scans the surface of the photoconductor sample by the electron beam,

a distribution of the electrostatic latent image on the surface of the sample being measured by a signal detected by the scanning,

wherein the exposure optical system includes a semiconductor laser as a light source, and the optical system includes a shutter which shields offset emission by a bias current of the semiconductor laser.

2. The electrostatic latent image measuring device according to claim 1 , wherein a luminous flux of the light source is irradiated outside an electron beam scanning area of the photoconductor sample.

3. The electrostatic latent image measuring device according to claim 1 , further comprising a unit which opens the shutter in connection with a synchronization signal of the exposure optical system.

4. The electrostatic latent image measuring device according to claim 3 , further comprising a unit which opens the shutter and closes the shutter after forming the electrostatic latent image with the detected synchronization signal of the exposure optical system as a trigger signal.

5. The electrostatic latent image measuring device according to claim 1 , further comprising a unit which illuminates the semiconductor laser Td+Tr late after receiving a synchronization signal as a trigger output, where a time to start opening the shutter after detecting the synchronization signal is Td and a time to open an effective diameter of a laser light after the start of the opening of the shutter is Tr.

6. The electrostatic latent image measuring device according to claim 1 , wherein a condition, Tr<Tf*Pon/Poff is satisfied, where one scanning time by the exposure optical system is Tf, the light volume of the offset emission by the bias current when turning off the semiconductor laser is Poff, and the light volume when illuminating the semiconductor laser is Pon.

7. The electrostatic latent image measuring device according to claim 1 , wherein the shutter is a mechanical shutter.

8. The electrostatic latent image measuring device according to Claim 1 , further comprising a unit which measures the distribution of the electrostatic latent image under a condition having an area where a component in a normal direction of the surface of the photoconductor sample of a speed of the incident charged particle reverses.

9. An electrostatic latent image measuring device, comprising:

a unit which irradiates an electron beam to a photoconductor sample within a vacuum chamber, and charges the photoconductor sample;

an exposure optical system which forms an electrostatic latent image on a surface of the photoconductor sample, the surface of the sample being scanned by the electron beam, and a distribution of the electrostatic latent image of the surface of the photoconductor sample being measured by a signal detected by the scanning;

a unit which forms a pattern of the electrostatic latent image having a known size on the surface of the photoconductor sample by irradiating light whose wavelength is 400-800 nm;

a unit which loads a latent image obtained as the electrostatic latent image; and

a unit which measures coordinates of the photoconductor sample, and

wherein the exposure optical system is disposed outside the vacuum chamber.

10. The electrostatic latent image measuring device according to claim 9 , further comprising a unit which projects and exposes a mask pattern having a known size as the unit which forms the pattern of the electrostatic latent image having a known size.

11. The electrostatic latent image measuring device according claim 9 , wherein two or more latent image patterns having a known interval on a sample are formed, and an average magnification is calculated from the loaded image data.

12. The electrostatic latent image measuring device according to claim 11 , wherein three or more latent image patterns having a known pitch on the sample are formed in line, and a local change in a magnification is measured from the loaded image data.

13. The electrostatic latent image measuring device according to claim 9 , wherein a pattern of a latent image having a known interval is formed by using a laser light scanning unit which performs optical scanning at a constant speed to the photoconductor sample by deflecting a luminous flux from a light source at an equal angular speed by a light deflector having a deflection and a reflection face and condensing the deflected luminous flux as a light spot on a surface to be scanned by an optical system for scanning and focusing, and a coordinate of the sample is calculated from data into which the latent image obtained as the electrostatic latent image is loaded.

14. An electrostatic latent image measuring device comprising:

a charged particle optical system which irradiates an electron beam and charges a photoconductor sample;

an exposure optical system which forms an electrostatic latent image on a surface of the photoconductor sample; and

a scanning unit which scans the surface of the photoconductor sample by the electron beam,

a distribution of the electrostatic latent image on the surface of the sample being measured by a signal detected by the scanning,

wherein the exposure optical system includes a semiconductor laser as a light source, and the optical system includes a shutter which shields offset emission by a bias current of the semiconductor laser, and

wherein the shutter is disposed outside a vacuum chamber so as to control noise by a change in an electromagnetic field.