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US4604753A
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Semiconductor laser module having an improved temperature control arrangement
Assignee: Hitachi Ltd
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Filing: 1983-11-25
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Granted: 1986-08-05
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Expires: 2003-11-25
Abstract
Abstract A semiconductor laser device is provided including semiconductor laser element, a PN-junction element which is used for temperature detection, and a thermoelectric heat pump which is electrically connected to the PN-junction element. According to this arrangement, heat developing from the semiconductor laser element is sensed by exploiting the fact that the forward voltage V F of the PN-junction element or PN-junction diode changes in correspondence with the change of the ambient temperature (this phenomenon itself is a matter already known), and the change of the forward voltage V F is fed back to the thermoelectric heat pump. Therefore, even when the semiconductor laser device is placed in the condition of a very high ambient temperature (open air temperature), the semiconductor laser element is cooled down to a predetermined temperature by the thermoelectric heat pump so as to produce a prescribed optical power at all times. Thus, the semiconductor laser element itself is driven in an appropriate temperature condition (for example, 25° C.), so that the degradation of the semiconductor laser element can be prevented.
Inventors
- 👤 Masaaki Sawai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 00:25
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/02; H01S5/024; H01S5/02407; H01S5/02415; H10; H10W; H10W72/00; H10W72/50; H01S2301/00; H01S2301/14; H01S2301/18; H01S5/022; H01S5/02208; H01S5/02212; H01S5/026; H01S5/0262; H01S5/0264; H01S5/06; H01S5/068; H01S5/0683; H10W72/551; H10W72/552; H10W72/5522; H10W72/851; H10W72/874; H10W72/884; H10W90/00; H10W90/701; H10W90/731; H10W90/732
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
113 words
A semiconductor laser module comprising: a semiconductor laser element; a semiconductor submount of a first conductivity type which supports said semiconductor laser element; a semiconductor region of a second conductivity type opposite to said frist conductivity type formed in said submount and located adjacent to said laser element so as to form a PN-junction element for detecting heat developing from said laser element and an ambient temperature in the area of said laser element; and a thermoelectric heat pump which is electrically connected to said PN-junction element and which is coupled to said laser element to control the temperature of said laser element in accordance with an output signal from said PN-junction element.
Claim 2
Dependent Claim
113 words
A semiconductor laser module comprising: a semiconductor laser element; a semiconductor submount of a first conductivity type which supports said semiconductor laser element; a semiconductor region of a second conductivity type opposite to said frist conductivity type formed in said submount and located adjacent to said laser element so as to form a PN-junction element for detecting heat developing from said laser element and an ambient temperature in the area of said laser element; and a thermoelectric heat pump which is electrically connected to said PN-junction element and which is coupled to said laser element to control the temperature of said laser element in accordance with an output signal from said PN-junction element.
Claim 3
Dependent Claim
18 words
A semiconductor laser module as defined in claim 1, wherein said submount is made of a compound semiconductor.
Claim 4
Dependent Claim
47 words
A semiconductor laser module as defined in claim 1, further comprising a temperature control circuit coupled between said PN-junction element and said heat pump, said temperature control circuit including means for monitoring the forward voltage of said PN-junction element to detect the temperature at said PN-junction element.
Claim 5
Dependent Claim
38 words
A semiconductor laser module as defined in claim 3, wherein said temperature control circuit includes means for operating said heat pump when the temperature of said PN-junction element increases above a predetermined level to cool said laser element.
Claim 6
Dependent Claim
38 words
A semiconductor laser module as defined in claim 3, wherein said temperature control circuit includes means for operating said heat pump when the temperature of said PN-junction element decreases below a predetermined level to heat said laser element.
Claim 7
Dependent Claim
38 words
A semiconductor laser module as defined in claim 4, wherein said temperature control circuit includes means for operating said heat pump when the temperature of said PN-junction element decreases below a predetermined level to heat said laser element.
Claim 8
Dependent Claim
22 words
A semiconductor laser module as defined in claim 1, wherein a metal support is interposed between said heat pump and said submount.
Claim 9
Dependent Claim
32 words
A semiconductor laser module as defined in claim 3, wherein said temperature control circuit produces an output signal to maintain the temperature of said laser element between 25° C. and 50° C.
Claim 10
Dependent Claim
129 words
A semiconductor laser module comprising: a semiconductor laser element; a semiconductor body including a first conductivity type region, which supports said semiconductor laser element; a semiconductor region of a second conductivity type opposite to said first conductivity type formed in said first conductivity type region so as to form a PN-junction element for detecting heat developing from said laser element and an ambient temperature in the area of said laser element; a photosensor located adjacent to said laser element for monitoring an optical output power of said semiconductor laser element; and a thermoelectric heat pump which is electrically connected to said PN-junction element and which is coupled to said laser element to control the temperature of said laser element in accordance with an output signal from said PN-junction element.
Claim 11
Dependent Claim
129 words
A semiconductor laser module comprising: a semiconductor laser element; a semiconductor body including a first conductivity type region, which supports said semiconductor laser element; a semiconductor region of a second conductivity type opposite to said first conductivity type formed in said first conductivity type region so as to form a PN-junction element for detecting heat developing from said laser element and an ambient temperature in the area of said laser element; a photosensor located adjacent to said laser element for monitoring an optical output power of said semiconductor laser element; and a thermoelectric heat pump which is electrically connected to said PN-junction element and which is coupled to said laser element to control the temperature of said laser element in accordance with an output signal from said PN-junction element.
Claim 12
Dependent Claim
23 words
A semiconductor laser module as defined in claim 9, wherein said PN-junction element and said photosensor are respectively formed in individual semiconductor bodies.
Claim 13
Dependent Claim
31 words
A semiconductor laser module as defined in claim 9, wherein said PN-junction element and said photosensor are respectively formed in said semiconductor body, on which said semiconductor laser element is mounted.
Claim 14
Dependent Claim
35 words
A semiconductor laser module as defined in claim 11, wherein said photosensor is located on a laser beam axis of said semiconductor laser element, and said PN-junction element is located off said laser beam axis.
Claim 15
Dependent Claim
47 words
A semiconductor laser module as defined in claim 9, further comprising a temperature control circuit coupled between said PN-junction element and said heat pump, said temperature control circuit including means for monitoring the forward voltage of said PN-junction element to detect the temperature at said PN-junction element.
Claim 16
Dependent Claim
38 words
A semiconductor laser module as defined in claim 13, wherein said temperature control circuit includes means for operating said heat pump when the temperature of said PN-junction element increases above a predetermined level to cool said laser element.
Claim 17
Dependent Claim
38 words
A semiconductor laser module as defined in claim 13, wherein said temperature control circuit includes means for operating said heat pump when the temperature of said PN-junction element decreases below a predetermined level to heat said laser element.
Claim 18
Dependent Claim
38 words
A semiconductor laser module as defined in claim 14, wherein said temperature control circuit includes means for operating said heat pump when the temperature of said PN-junction element decreases below a predetermined level to heat said laser element.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-08-04 | 1990-02-03 | 1990-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-08-04 | 1994-02-03 | 1994-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-08-04 | 1998-02-03 | 1998-08-05 | $7700.00 | Window Closed / Lapsed |