1. Field of the Invention
The present invention relates to an optical measuring machine for forming optical image(s) of a target object mounted on a stage on a screen.
2. Description of Related Art
There have been known optical measuring machines such as projectors, an example of which: irradiates illumination light on a target object mounted on a stage; projects light transmitted or reflected from the target object on a screen in a magnified manner; and measures a dimension, a shape or the like of the target object based on optical image(s) formed on the screen in a magnified manner.
For instance, a projector with a two-axis linear encoder being provided on the stage thereof can measure a dimension, a shape or the like of the target object by aligning a target portion (e.g., edge section) of the optical image of the target object formed on the screen to a reference point on the screen and reading its two-dimensional coordinate on the stage at this time.
When the optical image(s) needs to be stored while such an optical measuring machine is being used, a general method is to directly photograph the screen on which the optical image(s) is formed using a photographic device such as a silver salt camera or a digital camera.
Document 1 (JP-A-5-264216) discloses a projector capable of photographing a portion of the optical image(s) using a dedicated photographing unit provided behind the screen.
However, when images are stored using a photographic device such as a camera, the stored images may vary depending on photographing conditions such as device type, illuminating method and photographing method, and photographers. In addition, in photographing the optical image(s), a photographic device such as a camera is required to be prepared separately from the optical measuring machine, which may lead to complication of operation(s).
When the projector according to Document 1 is used, the entirety of the optical image(s) cannot be visually observed when photographed because a dedicated photographing unit is required to be provided behind the screen. Accordingly, it has been difficult to simultaneously conduct photographing and a measurement.