JPH08222795A - Semiconductor light emitting element array module - Google Patents

Abstract

PURPOSE: To reduce the difference between the temperature detected by a temperature detecting element and the actual temperature of a semiconductor light emitting element array, and decrease performance deterioration, by estimating and outputting a temperature by using a specific function from the detected temperature of the temperature detecting element. CONSTITUTION: A plurality of temperature detecting elements 5 are arranged on a semiconductor element mounting board 2 serving as a heat introducing board, adjacent to semiconductor light emitting element array 1. A temperature control equipment 6 has a pre-stage signal processing part 8 which estimates and outputs the temperature of the semiconductor light emitting element array 1, from the detected temperatures of a plurality of the temperature detecting elements 5, by using a specific function. On the basis of the estimated temperature signal outputted from the pre-stage signal processing part 8, the temperature control equipment 6 controls a cooling equipment 4, so that the temperature of the semiconductor light emitting element array module is controlled by the temperature estimated by extrapolation using an arbitrary function, on the basis of the detected temperatures of the temperature detecting elements 5. Thereby the high stable operation temperature of the semiconductor light emitting element array 1 can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor light emitting element element array module whose thermal characteristics are stabilized.

[0002]

2. Description of the Related Art In recent information processing devices and long-distance, large-capacity optical communication devices, the required performance of semiconductor light emitting elements is increasing more and more. For example, FDM (Frequency Divisi)
on Multiplexing) optical communication system (reference: H.Toba, K.Oda, K.Nakanis)
hi, N.Shibata, K.Nosu, N.Takano, and M.Fukuda, “A 1
00 channel optical FDM transmission / distribution at
622 Mb / s over 50 kM, ”IEEE J. LightwaveTechnol.,
vol.LT-8, pp.1396-1401, Sept.1990.)
Assuming that the wavelength spacing of the optical carriers in this FDM optical communication system is designed to be about 0.8 angstrom, sub-angstrom is required for the accuracy and stability of the oscillation wavelength of the semiconductor laser diode as the semiconductor light emitting element.

By the way, since the temperature dependence of the semiconductor laser diode is usually about 1 Å / ° C., even if the operating temperature of the semiconductor laser diode changes by about 1 ° C., it causes a serious obstacle to the optical communication system. As in this example, since the characteristics of the semiconductor light emitting element are very sensitive to temperature, temperature control of the semiconductor light emitting element has been an important issue.

FIG. 5 shows a configuration example of a conventional semiconductor light emitting element element array module, 1 is a semiconductor light emitting element element array, 2 is a semiconductor element mounting / heat introducing plate, and is usually a good heat conductor such as diamond. Made Three
Is a member for heat diffusion and is usually made of a heat conductive metal such as copper or aluminum. Reference numeral 4 denotes a cooling device, which is made of, for example, an electronic cooling element. Reference numeral 5 denotes a temperature detecting element for detecting the temperature of the semiconductor light emitting element array 1, which is installed on the semiconductor element mounting / heat introducing plate 2. Reference numeral 6 is a temperature control device for controlling the temperature of the cooling device 4, and 7 is a cable connecting the temperature detecting element 5 and the temperature control device 6 and the cooling device 4 and the temperature control device 6. The heat generated in the semiconductor light emitting element array 1 passes through the semiconductor element mounting / heat introducing plate 2 and the heat diffusion member 3 while being spread, and is absorbed by the cooling device 4. This cooling device 4
The amount of heat absorbed by the temperature control device 6 is set so that the detected temperature T _{5 of the} temperature measuring element 5 installed on the semiconductor element mounting / heat introducing plate 2 or in the heat diffusion member 3 becomes constant. Controlled by.

As shown in FIG. 5, in the structure of the conventional semiconductor light emitting element element array module, the temperature detecting element 5 is used.
Means that the temperature of the semiconductor light emitting element array 1 is not measured, but the temperature of the semiconductor element mounting / heat introducing plate 2 or the heat diffusion member 3 is measured. However, since the heat flow Q generated by the semiconductor light emitting element array 1 spreads inside the semiconductor element mounting / heat introducing plate 2 and the heat diffusion member 3, the semiconductor element mounting / heat introducing plate 2 and the heat diffusion member 3 are arranged. Even if a member having high thermal conductivity is used for 3, a temperature difference will occur between the detected temperature T _{5 of the} temperature detecting element ₅ and the actual temperature T ₁ of the semiconductor light emitting element array 1. Now, assuming that the thermal resistance between the semiconductor light emitting element array 1 and the temperature detecting element 5 is R _t , the temperature difference ΔT between the semiconductor light emitting element array 1 and the temperature detecting element 5 is: temperature difference (ΔT) = thermal resistance ( R _t ) × heat flow (Q).

Here, if the amount of heat generated by the semiconductor light emitting element array 1 fluctuates for some reason, the heat flow Q passing through the semiconductor element mounting / heat introducing plate 2 and the heat diffusing member 3 fluctuates. From the relational expression between the temperature difference ΔT and the heat flow Q, the fluctuation of the heat flow Q is multiplied by the thermal resistance R _t and converted into the temperature difference ΔT. Therefore, in the configuration of the conventional semiconductor light emitting element element array module in which the thermal resistance R _t between the semiconductor light emitting element element array 1 and the temperature detecting element 5 is large, the temperature difference ΔT also largely changes. Since the temperature control device 6 controls the cooling device 4 so as to keep the detected temperature T ₅ of the temperature detecting element 5 constant, the actual temperature T ₁ of the semiconductor light emitting element element array 1 increases, for example, when the amount of heat generation increases, If the calorific value decreases, the actual temperature T ₁ will decrease.

Here, a two-dimensional thermal analysis will be tried by taking a semiconductor laser diode array as an example of the semiconductor light emitting element element array 1. FIG. 6 shows the configuration of the analysis example. The semiconductor laser diode array is made of indium phosphide (thermal conductivity 68 W /
mk), and the dimensions are 1 mm width × 80 μm thickness,
Semiconductor laser diode elements A, B,
C and D are formed at 250 μm intervals. The semiconductor element mounting and heat introduction plate 2 is made of diamond (heat conductivity of 2000
W / mk), and the dimensions are 8 mm width × 300 μm thickness. The heat diffusion member 3 is made of copper (heat conductivity of 39
0 W / mk), the dimensions are 16 mm width x 10 thickness
mm. The temperature measuring element 5 is arranged on the semiconductor device mounting / heat introducing plate 2 from the semiconductor laser diode array 1 d =
It is assumed that they are installed at a position separated by 0.75 mm or at the center position of the heat diffusion member 3. The bottom surface of the heat diffusion member 3 has isothermal boundary conditions.

The result of a two-dimensional thermal analysis of this example is shown in FIG. In the figure, the upper curve is the temperature distribution of the upper surface of the semiconductor laser diode array 1, and the temperatures of the respective semiconductor laser diode elements A, B, C, D are 7.205 for the outer semiconductor laser diode elements A, D.
Semiconductor laser diode elements B and C at 1 ° C inside
Was 7.2853 ° C. The lower curve is the temperature distribution on the upper surface of the semiconductor element mounting / heat introducing plate 2, and the symbol ◯ indicates the temperature measuring element 5 installed on the upper surface of the semiconductor element mounting / heat introducing plate 2.
Detection temperature (2.3885 ° C.), □ indicates the detection temperature (1.4003) of the temperature detecting element 5 installed in the heat diffusion member 3.
° C).

In this semiconductor light emitting element element array module, temperature control is performed so as to compensate for an increase in the temperature detected by the temperature detecting element 5. Therefore, the semiconductor light emitting element element array module stops oscillating at the temperature of the semiconductor light emitting element element array module. From the temperature when you are doing 2.
It is cooled by the cooling device 4 only at 3885 ° C. (1.4003 ° C. if the temperature detecting element 5 is inside the thermal diffusion member 3). As a result, the semiconductor laser diode element has a temperature of 2.3885 ° C. (or 1.400 ° C.) from the temperature rise.
3 ° C), and the outside semiconductor laser diode elements A and D have a temperature of 4.8166 ° C (or 5.8048).
℃), semiconductor laser diode elements B and C inside
Is 4.8968 ° C. (or 5.8048 ° C.), the operation is performed at a high temperature from the oscillation stopped state.

Next, it is assumed that the semiconductor laser diode element A is deteriorated and the heat generation is stopped. The result of the two-dimensional thermal analysis is shown in FIG. The temperature rise of the semiconductor laser diode elements A, B, C, D is 6.5182 ° C. for the semiconductor laser diode element B, 6.5905 ° C. for the semiconductor laser diode element C, 6.5476 ° C. for the semiconductor laser diode element D, and the temperature measurement is performed. The detection temperature of the element 5 was 2.1910 ° C. on the semiconductor element mounting / heat introducing plate 2, and 1.0503 ° C. in the heat diffusion member 3. The operating temperature of the semiconductor laser diode element is 2.910 from the above temperature rise.
C. (or 1.0503 ° C.), semiconductor laser diode element B is 4.3272 ° C. (or 5.4679 ° C.), semiconductor laser diode element C is 4.3995 ° C. (or 5.5402 ° C.), semiconductor laser diode The temperature of Element D reached 4.3566 ° C (or 5.4973 ° C).

FIG. 8 shows fluctuations in operating temperatures of the other semiconductor laser diode elements B, C and D before and after deterioration of the semiconductor laser diode element A (ON / OFF of heat generation). Semiconductor laser diode element B
0.4171 ° C (or -0.5696 ° C), the semiconductor laser diode element C is -0.3448 ° C (or -0.4973 ° C), and the semiconductor laser diode element D is -0.3075 ° C (or -0.460).
It became 0 degreeC). As described above, in the configuration of the conventional semiconductor light emitting element element array module, since the actual temperature T ₁ of the semiconductor light emitting element element array 1 cannot be kept constant, wavelength drift or the like occurs.

[0012]

SUMMARY OF THE INVENTION The present invention reduces the temperature difference between the temperature detected by the temperature detecting element and the actual temperature of the semiconductor light emitting element element array when the semiconductor light emitting element element array is mounted, thereby deteriorating the performance. It is an object of the present invention to provide a semiconductor light emitting element element array module having a small number of components.

[0013]

In order to solve the above problems, the present invention provides a semiconductor light emitting device element array, a semiconductor device mounting / heat introducing plate, a heat diffusion member, a temperature detecting device, a temperature control device, and a cooling device. In a semiconductor light emitting element element array module configured with a device, a plurality of temperature measuring elements are arranged adjacent to the semiconductor light emitting element element array on the semiconductor element mounting / heat introducing plate, and the temperature control device is Using a predetermined function from the detected temperatures of the plurality of temperature detecting elements, a pre-stage signal processing unit for estimating and outputting the temperature of the semiconductor light emitting element element array is provided, and the estimated temperature signal output from the pre-stage signal processing unit A temperature control device controls the cooling device to provide a semiconductor light emitting element element array module.

[0014]

In the semiconductor light emitting element element array module of the present invention, the temperature of the semiconductor light emitting element element array is extrapolated from the detected temperatures of the plurality of temperature detecting elements on the semiconductor element mounting / heat introducing plate by extrapolation by an arbitrary function. The temperature of the semiconductor light emitting element element array module is estimated and the temperature of the semiconductor light emitting element element array module is controlled by the estimated temperature. It is possible to realize a semiconductor light emitting element element array module in which the operating temperature of the semiconductor light emitting element element array is more stable than in the prior art in which the temperature is controlled.

[0015]

【Example】

[Embodiment 1] FIG. 1A is an overall view of the configuration of a semiconductor laser diode array module which is a first embodiment of a semiconductor light emitting element element array module of the present invention.
FIG. 2B is a partially enlarged view of the main part thereof, and 1 is a semiconductor light emitting element element array, as in the conventional example.
In the figure, a plurality of semiconductor light emitting element elements (semiconductor laser diode elements) are provided for simplification of description.
It is assumed that four A, B, C, and D are arranged in a line along the paper surface and that they are sequentially arranged in a state where they extend vertically to the paper surface.

Reference numeral 2 denotes a semiconductor element mounting / heat introducing plate,
It is usually made of a good thermal conductor such as diamond. Reference numeral 3 denotes a heat diffusion member, which is usually made of a heat conductive metal such as copper or aluminum. A cooling device 4 is made of, for example, an electronic cooling element. Reference numeral 5 denotes a temperature detecting element, which detects the temperature of the semiconductor light emitting element element array 1,
Adjacent to the semiconductor light emitting element element array 1, on the semiconductor element mounting / heat introducing plate 2, temperature measuring elements 5 _1, 5 _2,
3 of 5 ₃ are arranged.

Reference numeral 6 is a temperature control device for the cooling device 4, and 8 is a pre-stage signal processing unit for outputting the temperature extrapolated from the detected temperatures of the temperature detecting elements 5 _1, 5 _2, 5 _{3 to} the temperature control device 6 as a control signal. , 7 are between the temperature measuring element 5 and the preceding signal processing unit 8,
It is a cable connecting between the cooling device 4 and the temperature control device 6, and between the temperature control device 6 and the pre-stage signal processing unit 8.

The first embodiment of the present invention was analyzed again using an example of a semiconductor laser diode array in which the conventional structure of FIG. 5 was subjected to a two-dimensional thermal analysis. The temperature rise of the semiconductor laser diode elements A, B, C, D is 7.2051 ° C. for the outer semiconductor laser diode elements A, D, and 7.2 for the inner semiconductor laser diode elements B, C.
It is 853 ° C., which is no different from the result ((a) of FIG. 7) by the conventional configuration of FIG. 2A shows the temperature distribution on the upper surface of the semiconductor element mounting / heat introducing plate 2, and ◯ indicates the temperature measuring elements 5 _{1 ,} 5 ₂ installed on the upper surface of the semiconductor element mounting / heat introducing plate _{2. ,} 5 ₃ detected temperature (2.388
5 ° C., 2.0422 ° C., 1.8246 ° C.).

The pre-stage signal processing unit 8 includes temperature measuring elements 5 _1, 5
_The temperature extrapolated from the detected temperatures of _2, 5 ₃ is the temperature control device 6
Output to. FIG. 2A shows an example in which a quadratic polynomial is adopted as an extrapolation curve. Based on this curve, the pre-stage signal processing unit 8 outputs 3.0024 ° C. (□ in the figure) as an extrapolated value. Since the temperature control is performed using this extrapolated value, the temperature of the semiconductor light emitting element element array module is cooled by 3.0024 ° C. in the cooling device 4 from the temperature when the semiconductor light emitting element element stops oscillating. As a result, the semiconductor laser diode element subtracts 3.0024 ° C. from the temperature rise,
3. The outer semiconductor laser diode elements A and D are 4.
The semiconductor laser diode elements B and C on the inner side are operated at a high temperature of 2027 ° C. and 4.2829 ° C. from the oscillation stopped state.

Next, it is assumed that the semiconductor laser diode element A is deteriorated and the heat generation is stopped. As a result of the two-dimensional thermal analysis, the temperature rise of the semiconductor laser diode element was 6.518 in the semiconductor laser diode element B.
2 ° C, semiconductor laser diode element C 6.59
05 ℃, semiconductor laser diode element D 6.5
476 ° C., which is no different from the result ((b) of FIG. 7) obtained by the conventional configuration of FIG. 5.

FIG. 2B shows the temperature distribution on the upper surface of the semiconductor element mounting / heat introducing plate 2, and ◯ indicates the temperature detecting element 5 installed on the upper surface of the semiconductor element mounting / heat introducing plate 2. _1, 5 _2,
5, which is a _third detection temperature. The detected temperature is the temperature measuring element 5 ₁
Was 1.8319 ° C., the temperature measuring element 5 ₂ was 1.5614 ° C., and the temperature measuring element 5 ₃ was 1.3929 ° C. The pre-stage signal processing unit 8 outputs a temperature of 2.2915 ° C. (□ in the figure) obtained by extrapolating a quadratic curve from the detected temperatures of the temperature detecting elements 5 _1, 5 _{2, and} 5 ₃ to the temperature control device 6. Regarding the operating temperature of the semiconductor laser diode element, 2.2915 ° C. is subtracted from the temperature rise, and the operating temperature of the semiconductor laser diode element B is 4.
2267 ° C., semiconductor laser diode element C is 4.2990 ° C., semiconductor laser diode element D
Was 4.2561 ° C.

FIG. 3 shows fluctuations in operating temperature of other semiconductor laser diode elements before and after deterioration of the semiconductor laser diode element A (ON / OFF of heat generation).
Semiconductor laser diode element B is -0.0562
℃, semiconductor laser diode element C 0.016
1 ℃, semiconductor laser diode element D is 0.05
The fluctuation was as small as 34 ° C. As described above, in the present invention, the fluctuations in the operating temperature of the other semiconductor laser diode elements due to the failure of the semiconductor laser diode element A are smaller than those in the conventional configuration.

[Embodiment 2] FIG. 4A is an overall view of the configuration of a semiconductor laser diode array module according to a second embodiment of the present invention, and FIG. 4B is a partially enlarged view of the main part thereof. The second embodiment is exactly the same as the first embodiment in the components and the operation thereof. Therefore, the same parts as those in FIG. 1 are designated by the same reference numerals and detailed description thereof will be omitted. The difference is that in the first embodiment, the temperature measuring element 5 _1,
While 5 _{2 and} 5 ₃ are normal bulk-shaped temperature measuring elements, in the second embodiment, the temperature measuring elements 5 _1, 5 _{2 and} 5 ₃ are thin film-shaped on the semiconductor element mounting / heat introducing plate 2. Is the point that is formed. In the first embodiment, the presence of a "brazing material" or "adhesive material" for mounting the bulk-shaped temperature measuring element on the semiconductor element mounting / heat introducing plate 2, and further, the temperature measuring element itself is in the bulk shape. Although there is a drop in the detected temperature by itself, there is no such drop in the detected temperature in the second embodiment. Therefore, the effect of the invention is greater than that of the first embodiment.

Incidentally, in both the first and second embodiments,
Although the configuration has been shown in which the extrapolated value is obtained from three temperature measuring elements using a quadratic curve, however, the number of temperature measuring elements and the extrapolation function are not limited, and the semiconductor laser diode array module is described as an example. However, this does not limit the type of semiconductor light emitting device,
Needless to say. Further, although the case where the electronic cooling element is used as the cooling device is described as an example, it goes without saying that the electronic cooling element is not limited to the electronic cooling element.

[0025]

As described above, according to the present invention, in the structure of the semiconductor light emitting element element array module, a plurality of temperature detecting elements are arranged on the semiconductor element mounting / heat introducing plate, and the temperature control device is The semiconductor device mounting / heat introducing plate has a pre-stage signal processing unit for extrapolating from the detected temperatures of the plurality of temperature detecting devices by an arbitrary function to estimate and output the temperature of the semiconductor light emitting device element. Since the temperature control device controls the cooling device by the signal output from the signal processing unit, it is possible to realize a semiconductor light emitting element element array module in which the operating temperature of the semiconductor light emitting element element is more stable than before.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a semiconductor light emitting element element array module according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining what kind of estimated temperature the pre-stage signal processing unit of the semiconductor light emitting element element array module according to the first embodiment of the present invention outputs.

FIG. 3 illustrates how the operating temperature of another semiconductor laser diode element fluctuates due to fluctuations in heat generation of the semiconductor laser diode element A in the case of the semiconductor light emitting element element array module according to the first embodiment of the present invention. FIG.

FIG. 4 is a diagram showing a configuration of a semiconductor light emitting element element array module according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of a semiconductor light emitting element element array module according to a conventional technique.

FIG. 6 is a configuration diagram in which the temperature controllability in the prior art is analyzed.

FIG. 7 is a diagram for explaining how the temperature of a semiconductor laser diode element changes due to a change in operating state when a semiconductor light emitting element element array module is constructed by a conventional technique.

FIG. 8 is a diagram for explaining how the operating temperature of another semiconductor laser diode element fluctuates due to fluctuations in heat generation of the semiconductor laser diode element A when a semiconductor light emitting element element array module is constructed by a conventional technique. .

[Explanation of symbols]

1 semiconductor light emitting element element array 2 semiconductor element mounting and heat introduction plate 3 heat diffusion member 4 cooling device 5 temperature measuring elements 5 _1, 5 _2, 5 ₃ temperature measuring element 6 temperature control device 7 cable 8 pre-signal processing unit A, B, C, D Semiconductor laser diode element

Claims (2)

[Claims] 1. A semiconductor light emitting element array, comprising a semiconductor light emitting element array, a semiconductor element mounting / heat introducing plate, a heat diffusion member, a temperature measuring element, a temperature control device and a cooling device, On the element mounting and heat introduction plate, a plurality of temperature measuring elements are arranged adjacent to the semiconductor light emitting element element array, the temperature control device, using a predetermined function from the detected temperature of the plurality of temperature measuring elements, It has a pre-stage signal processing unit for estimating and outputting the temperature of the semiconductor light emitting element element array, and the temperature control device controls the cooling device by the estimated temperature signal output from the pre-stage signal processing unit. Semiconductor light emitting element element array module. 2. The semiconductor light emitting element element array module according to claim 1, wherein there are three temperature detecting elements and the function is a quadratic polynomial.