US 7,581,880 B2Granted

Radiant-temperature measurement device, light-source temperature control device, image projection apparatus and radiant-temperature measurement method

AssigneeMitsubishi Electric Corporation

InventorsHiroyuki Kawano, Tatsuki Okamoto, Toshirou Nakashima, Kazuo Takashima

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Abstract

A radiant-temperature measurement device includes a time-based data measurement unit for acquiring, based on an intensity of first light, a first data value during a first measuring interval in a first intensity duration, and a second data value during a second measuring interval in a second intensity duration. The time-based data measurement unit is also for acquiring, based on an intensity of second light, a third data value in a first wavelength band, and a fourth data value in a second wavelength band, during the first measuring interval, and a fifth data value in the first wavelength band, and a sixth data value in the second wavelength band, during the second measuring interval. The radiant-temperature measurement device also includes a temperature calculation unit for calculating, based on the first, second, third, fourth, fifth, and sixth data values, a temperature of a light source at its light-emitting end.

Claims11

Dependent claims

A radiant-temperature measurement device, comprising:

a first measurement unit for measuring, from among light-source light emitted from a light source having light-emitting ends in which a pattern of variation in light intensity versus time is repeated at predetermined periods each including a first intensity duration and a second intensity duration during which the second intensity differs from the first intensity, an intensity of first light originating in the light-source light;
a second measurement unit for measuring an intensity of second light, in which stray light originating in the light-source light is superimposed onto thermal radiation emitted from one of the light-source's light-emitting ends, in each of a first wavelength band and a second wavelength band, whose wavelengths differ from each other;
a time-based data measurement unit
for acquiring, based on the intensity of the first light measured by the first measurement unit, a first data value during a first measuring interval in the first intensity duration, and a second data value during a second measuring interval in the second intensity duration, and
for acquiring, based on the intensity of the second light measured by the second measurement unit, a third data value in the first wavelength band, and a fourth data value in the second wavelength band, during the first measuring interval, and a fifth data value in the first wavelength band, and a sixth data value in the second wavelength band, during the second measuring interval;
and
a temperature calculation unit for calculating, based on the first, second, third, fourth, fifth, and sixth data values, the temperature of the light source at its light-emitting end.

4 more elements

A radiant-temperature measurement device, comprising:

a measurement unit
for measuring, from among light-source light emitted from a light source having light-emitting ends in which a pattern of variation in light intensity versus time is repeated at predetermined periods each including a first intensity duration and a second intensity duration during which the second intensity differs from the first intensity, an intensity of first light originating in the light-source light, during a predetermined measuring interval, in either of a first wavelength band or a second wavelength band, whose wavelengths differ from each other, and
for measuring an intensity of second light, in which stray light originating in the light-source light is superimposed onto thermal radiation emitted from one of the light-source's light-emitting ends, during a measuring interval that differs from the predetermined measuring interval, in each of a first wavelength band and a second wavelength band, whose wavelengths differ from each other;
a drive unit for changing either a position or a direction of said measurement unit so that, during the predetermined measuring interval, said measurement unit measures the intensity of the first light, and during the measuring interval that differs from the predetermined measuring interval, said measurement unit measures the intensity of the second light;
a time-based data measurement unit
for acquiring, based on the intensity of the first light measured by the measurement unit, a first data value in the first intensity duration and during a first measuring interval in which said measurement unit measures the intensity of the first light, and a second data value in the second intensity duration and during a second measuring interval in which said measurement unit measures the intensity of the first light, and
for acquiring, based on the intensity of the second light measured by the measurement unit, a third data value in the first wavelength band, and a fourth data value in the second wavelength band, in the first intensity duration and during a third measuring interval in which said measurement unit measures the intensity of the second light, and a fifth data value in the first wavelength band, and a sixth data value in the second wavelength band, in the second intensity duration and during a fourth measuring interval in which said measurement unit measures the intensity of the second light;
and
a temperature calculation unit for calculating, based on the first, second, third, fourth, fifth, and sixth data values, the temperature of the light source at its light-emitting end.

6 more elements

A method of measuring a radiation-temperature, comprising:

measuring, from among light-source light emitted from a light source having light-emitting ends in which a pattern of variation in light intensity versus time is repeated at predetermined periods each including a first intensity duration and a second intensity duration during which the second intensity differs from the first intensity, an intensity of first light originating in the light-source light;
measuring an intensity of second light, in which stray light originating in the light-source light is superimposed onto thermal radiation emitted from one of the light-source's light-emitting ends, in each of a first wavelength band λ1 and a second wavelength band λ2, whose wavelengths differ from each other;
acquiring, based on the intensity of the first light, a first data value a0 during a first measuring interval in the first intensity duration, and a second data value b0 during a second measuring interval in the second intensity duration;
acquiring, based on the intensity of the second light, a third data value a(λ1) in the first wavelength band λ1, and a fourth data value a(λ2) in the second wavelength band λ2, during the first measuring interval, and a fifth data value b(λ1) in the first wavelength band λ1, and a sixth data value b(λ2) in the second wavelength band λ2, during the second measuring interval;
and
calculating, using a calculation unit, the temperature of the light source at its light-emitting end in such a way that, by substituting the first data value a0, the second data value b0, the third data value a(λ1), the fourth data value a(λ2), the fifth data value b(λ1), and the sixth data value b(λ2) into Equation 1 and Equation 2 a thermal radiation intensity I1 in the first wavelength band λ1 and a thermal radiation intensity I2 in the second wavelength band λ2, in the thermal radiation emitted from one of the light-source's light-emitting ends, are separated from each other and evaluated, and simultaneously by substituting the thermal radiation intensity I1 in the first wavelength band λ1 and the thermal radiation intensity I2 in the second wavelength band λ2 into Equation 3, an intensity ratio R is obtained, and retained data showing the relationship between the intensity ratio R and the temperature is referred, wherein Equation 1, Equation 2, and Equation 3 are as follows:
I
⁢
⁢
1
=
a
⁡
(
λ
⁢
⁢
1
)
-
a
⁢
⁢
0
×
b
⁡
(
λ
⁢
⁢
1
)
-
a
⁡
(
λ
⁢
⁢
1
)
b
⁢
⁢
0
-
a
⁢
⁢
0
Equation
⁢
⁢
(
1
)
I
⁢
⁢
2
=
a
⁡
(
λ
⁢
⁢
2
)
-
a
⁢
⁢
0
×
b
⁡
(
λ
⁢
⁢
2
)
-
a
⁡
(
λ
⁢
⁢
2
)
b
⁢
⁢
0
-
a
⁢
⁢
0
,
and
Equation
⁢
⁢
(
2
)
R
=
I
⁢
⁢
1
I
⁢
⁢
2
.
Equation
⁢
⁢
(
3
)

124 more elements

Dependencies are inferred from the claim text.

Facts

Application: 11/754,493Filed 29 May 2007
Priority: JP 2006-24677312 Sep 2006
Published: US 2008/0062404 A113 Mar 2008
Granted: 1 Sep 2009
Term ends: Not estimatedThe source records don’t support an estimate.

Classification14 codes

G01J 5/602
Using determination of colour temperature: using selective, monochromatic or bandpass filtering
G01J 5/08
Constructional details: optical arrangements
G01J 5/0846
Optical arrangements: having multiple detectors for performing different types of detection, e.g. using radiometry and reflectometry channels
G01J 5/0859
Optical arrangements: sighting arrangements, e.g. cameras