Thermal measuring and testing – Temperature measurement – In spaced noncontact relationship to specimen
Reexamination Certificate
1999-12-13
2001-08-28
Hirshfeld, Andrew H. (Department: 2859)
Thermal measuring and testing
Temperature measurement
In spaced noncontact relationship to specimen
C374S141000, C033SDIG002, C362S035000, C362S259000
Reexamination Certificate
active
06280082
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a projector for projecting light to indicate a measurement area and a measuring device provided with such a projector for remotely measuring a surface temperature of an object to be measaured.
In a known projector for use in a radiation thermometer for remotely measuring a surface temperature of a measurement object, a laser beam source is disposed on an optical axis branched from a main optical axis of a measurement optical system for converging a radiant energy from a measurement object, and a point of measurement is indicated by forming a spot projection image on the measurement object by the laser beam source.
However, this projector is merely capable of indicating the center of the measurement area, but is incapable of constantly forming a projection image for a variety of measurement objects. Further, since this device does not indicate the outline of the measurement area, it is difficult to accurately visually confirm the measurement area.
U.S. Pat. No. 5,368,392 discloses a projector for use in a radiation thermometer which is so constructed as to form a ring-shaped projection image indicative of the outline of a measurement area on a measurement object. In this projector, to form the ring-shaped projection image, there is provided a mechanism for mechanically rotating a reflector for reflecting a laser beam. More specifically, in this mechanism, the reflector is inclined with respect to a line parallel with an optical axis of the radiation thermometer. The laser beam is directed at a predetermined angle with respect to the optical axis of the radiation thermometer. The reflector is rotated to reflect the inclined laser beam to produce a ring-shaped projection image on the measurement object. However, the laser beam is reflected with respect to an optical axis different from the optical axis along which the laser beam is emitted. This makes it difficult to accurately produce a ring-shaped projection image.
Also, this U.S. Patent discloses a mechanism for mechanically rotating the laser beam source about an optical axis. However, the direct rotation of laser beam source makes the construction of the projector complicated.
Also, this projector is merely capable of indicating the outline of the measurement area by the ring-shaped projection image, but incapable of indicating the center of the measurement area. Accordingly, the use of this projector is not suitable in the case that the fine adjustment of the optical axis is required.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a projector and a measuring device provided with a projector which have overcome the problems residing in the prior art.
It is another object of the present invention to provide a projector and a measuring device provided with a projector which can accurately indicate a measurement area on a measurement object and have an improved operability in simpler construction.
According to one aspect of the present invention, a projector for use in a measuring device comprises: an emitter which emits a beam of visible light to a measurement object along a predetermined optical axis; a rotary optical member which is operable to change the propagation direction of the visible light beam with respect to the predetermined optical axis in accordance with rotation of the rotary optical member; and a driver which rotates the rotary optical member about a rotation axis.
It may be appreciated that the rotary optical member is operable to transmit the, visible light beam therethrough, and the rotary optical member is formed with a refractive portion operable to refract the visible light beam at a predetermined angle with respect to the predetermined optical axis.
The refractive portion may be defined by an inclined principle plane intersecting the predetermined optical axis at a predetermined angle.
The rotary optical member may be further formed with a nonrefractive portion which allows the visible light beam to propagate along the predetermined optical axis.
The refractive portion may be defined by an inclined principle plane intersecting the predetermined optical axis at a predetermined angle. The nonrefractive portion may be defined by a through hole formed in a position of the rotary optical member which the predetermined optical axis passes through. Also, the nonrefractive portion may be defined by a plurality of through holes formed in positions of the rotary optical member which the predetermined optical axis passes during the rotation of the rotary optical member.
Further, the nonrefractive portion may be defined by a planar portion formed in a position of the rotary optical member which the predetermined optical axis passes through, the planar portion having incidence and emergence principle planes normal to the predetermined optical axis. Also, the nonrefractive portion may be defined by a plurality of planar portions formed in positions of the rotary optical member which the predetermined optical axis passes during the rotation of the rotary optical member, the planar portion having incidence and emergence principle planes normal to the predetermined optical axis.
The rotary optical member may be formed with a first refractive portion operable to refract the visible light beam at a first predetermined angle with respect to the predetermined optical axis, and a second refractive portion operable to refract the visible light beam at a second predetermined angle with respect to the predetermined optical axis, the second predetermined angle being different from the first predetermined angle.
The first refractive portion may be defined by a first inclined principle plane intersecting the predetermined optical axis at a first predetermined angle. The second refractive portion may be defined by a second inclined principle plane intersecting the predetermined optical axis at a second predetermined angle different from the first predetermined angle.
The rotary optical member may be provided with a first member being formed with a first refractive portion having a first refractive angle; a second member being formed with a second refractive portion having a second refractive angle; and a changer which is operable to shift a relative position of the first and second member to change a combined refractive angle of the first and second refractive angles. The first and second members each may be preferably an optical prism.
It may be appreciated that the rotary optical member is operable to reflect the visible light beam, and is formed with a reflective portion operable to reflect the visible light beam at a predetermined angle with respect to an axis normal to the predetermined optical axis. The reflective portion may be defined by an inclined reflective plane intersecting the predetermined optical axis at a predetermined angle.
The emitter may be preferably provided with a semiconductor laser operable to intermittently emit light at a frequency higher than a critical flicker frequency. Further, there may be provided a detector which detects a rotation of the rotary optical member; and a controller which is responsive to the detector and controls the emitter so as to emit light at a frequency which is a multiple of a rotation frequency of the rotary optical member.
According to another aspect of the present invention, a projector for use in a measuring device comprises: an emitter which emits a beam of visible light to a measurement object along a predetermined optical axis; a rotary optical member which is operable to transmit the visible light beam therethrough, and formed with a refractive portion operable to refract the visible light beam at a predetermined angle with respect to the predetermined optical axis and a nonrefractive portion operable to allow the visible light beam to propagate along the predetermined optical axis; and a driver which rotates the rotary optical member about a rotation axis.
Further, there may be preferably provided a controller which controls the driver, the controller having a first control mode of act
Aoyama Satoshi
Banno Takashi
Kitagawa Eiji
Kusatsugu Tatsuaki
Burns Doane , Swecker, Mathis LLP
Hirshfeld Andrew H.
Minolta Co. , Ltd.
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