JPH03102311A - Light beam scanner - Google Patents

Abstract

PURPOSE:To obtain the temperature under which stably oscillatable in a short time and to reduce the power consumption by setting plural wavelength stabilizing temperatures in a set temperature selecting means, and holding a diode at the set temperature closest to the ambient temperature. CONSTITUTION:The temperatures corresponding to plural wavelength stable areas of a laser diode are set previously in the set temperature selecting means 3. Then the temperature of the laser diode 1 is detected by a temperature detecting means 2 such as a thermistor and the set temperature selecting means 3 selects the set temperature which is closest to the detected temperature of the diode 1. Then an arithmetic control means 4 compares the diode temperature with the set temperature and the diode 1 is heated or cooled to the set temperature through the Peltier element of a temperature varying means 5, so the stable temperature is obtained in a short time and no uniform temperature is set, so the power consumption is reducible.

Description

[Detailed Description of the Invention] [Summary] Regarding a light beam scanning device using a laser diode and a hologram element, the present invention provides a method for starting up the laser diode to a stable set temperature in a short time, and also for starting up the laser diode to the set temperature. A light beam scanning device using a laser diode and a hologram element, which aims to reduce the required power consumption, includes a temperature detection means for detecting the temperature of the laser diode, and a plurality of wavelength stable regions in the laser diode. a set temperature selection means for setting a plurality of corresponding temperatures in advance and selecting a set temperature closest to the detected temperature of the laser diode; and comparing the detected temperature of the laser diode and the selected set temperature. arithmetic control means for calculating and outputting a predetermined control signal; and heating or cooling of the laser diode in response to the output signal of the arithmetic control means so that the temperature of the laser diode matches the selected set temperature. The device is configured to include a temperature variable means.

[Industrial application field]

The present invention relates to a light beam scanning device, and particularly to a light beam scanning device using a laser diode and a hologram element.

In recent years, light beam scanning devices such as laser printer devices that use laser diodes and hologram elements have been put into practical use. In such a light beam scanning device using a laser diode and a hologram element, the laser light emitted from the laser diode must have a stable wavelength, so the temperature of the laser diode must be controlled to be constant. It is done like this. There is a need for a light beam scanning device that can control the temperature of a laser diode in a short time and with low power consumption.

[Conventional technology]

FIG. 5 is a diagram showing an example of a conventional light beam scanning device, which uses an f/θ optical system.

This conventional light beam scanning device! (For example, JP-A-59-1
46069) is widely used and uses a laser diode 101 as a light source, and a beam collimated by a collimating optical system 100 is transmitted to a rotating polygon mirror 102 and an f/θ lens 103.
A combination of the above is used to perform line scanning on the photoreceptor (photocondrum) 105, etc.

In addition to the light beam scanning device shown in FIG. 5, the light beam scanning device shown in FIG.
(see Publication No. 08) has been proposed.

This light beam scanning device includes a rotating polygon mirror 102 and an f.
A hologram element is used instead of the θ optical system 103. That is, the conventional optical beam scanning device shown in FIG. 6 scans the laser beam emitted from the laser diode 101 onto the photoconductor 104 using only two optical components: the hologram lens 105 and the hologram scanner (hologram disk) 106. It is designed to scan lines.

[Problem to be solved by the invention]

As described above, a light beam scanning device as shown in FIG. 6 has been proposed which can perform stable light beam scanning with a small number of components such as a laser diode and a hologram element. By the way, as in the light beam scanning device shown in FIG. 6, a hologram element (
Hologram lens 105 and hologram scanner 10
When using 6), the following points must be kept in mind.

First, the oscillation wavelength of the laser diode 101 fluctuates depending on changes in the surrounding temperature, which causes changes in the characteristics of the optical system, so it is necessary to stabilize the temperature of the laser diode 101 and keep it constant at the oscillation wavelength. There is.

FIG. 7 is a diagram for explaining the operation of the light beam scanning device of FIG. 6. As shown in the figure, in the conventional optical beam scanning device, the set temperature for stably operating the laser diode 101 is, for example, room temperature (20 to 25
Since the temperature of the laser diode is set at a constant temperature within 1°C, it is necessary to adjust the temperature of the laser diode so that the set temperature is maintained no matter what the ambient temperature is.

By the way, to adjust the temperature of the laser diode 101, for example, a thermoelectric cooling element such as a Bertier element is used to control the ambient temperature and the amount of temperature rise due to heat generation of the laser diode 101 itself, and maintain the laser diode 101 at a constant temperature. It is designed to emit laser light with a stable wavelength. However, environmental conditions such as the ambient temperature (5°C to 35°C) where the optical beam scanning device is used change, and it takes a certain amount of time to bring the laser diode 101 up to one predetermined set temperature. However, there are problems in that the basic specifications of the device cannot be met, such as the warm-up time being exceeded. Furthermore, in order to stabilize the temperature of the laser diode 101, it is necessary to raise the temperature to a predetermined set temperature regardless of the ambient temperature, and the power consumption becomes extremely large due to the current flowing through the Peltier element, etc. There is this.

In view of the above-mentioned problems with the conventional light beam scanning device, the present invention aims to start up a laser diode to a stable set temperature in a short time, and reduce the power consumption required to start up the laser diode to the set temperature. With the goal. [Means for Solving the Problems] FIG. F is a block diagram showing the principle of a light beam scanning device according to the present invention.

According to the present invention, there is provided a light beam scanning device using a laser diode 1 and a hologram element, and the temperature detection means 2 detects the temperature of the laser diode 1, and the laser diode 1 corresponds to a plurality of stable wavelength regions. a set temperature selection means 3 for setting a plurality of temperatures in advance to select a set temperature closest to the detected temperature of the laser diode 1; an arithmetic control stage 4 which compares and calculates and outputs a predetermined control signal; A light beam scanning device is provided, which includes a temperature variable stage 5 that matches the selected set temperature.

[For production]

According to the light beam scanning device of the present invention, the temperature detection stage 2 detects the temperature of the laser diode I, and the set temperature selection stage 3 selects the set temperature closest to the detected temperature of the laser diode I. . Here, in the set temperature selection stage 3, a plurality of temperatures corresponding to a plurality of wavelength stable regions in the laser diode l are set in advance, and from these plural set temperatures, the set temperature closest to the temperature of the laser diode 1 is selected. will be selected. Further, the temperature of the laser diode I detected by the calculation control means 4 is compared with the selected set temperature, and a predetermined control signal is output. Then, the laser diode 1 is heated or cooled by the temperature variable means 5 to which the output signal of the arithmetic control means 4 is supplied, and the temperature of the laser diode 1 is adjusted to match the selected set temperature.

As a result, the laser diode 1 can be raised to a stable set temperature (one of a plurality of set temperatures) in a short time, and the power consumption required to raise the laser diode 1 to the set temperature can be reduced. I can do it.

[Embodiment] Hereinafter, an embodiment of a light beam scanning device according to the present invention will be described with reference to the drawings.

First, before explaining the features of the present invention, an example of a light beam scanning device to which the present invention is applied will be described.

The present invention is applied to a device similar to the light beam scanning device having the laser diode and hologram element shown in FIG. 6 described above. That is, in Fig. 6,
The laser beam emitted from the laser diode 101 enters a hologram lens 105 that has a hologram formed on its surface, and further, the laser beam from the hologram lens 105 enters a rotating disk (hologram scanner) on which a hologram is formed. 106. Further, the laser beam that has passed through the hologram scanner 106 is line-scanned, for example, onto a photoreceptor (photocondrum) 104.

Here, the laser beam passing through the hologram lens 105 is
It is a wavefront that corrects aberrations of the scanning beam after passing through the hologram scanner 106.

Embodiments of the optical beam scanning device according to the present invention will be described in detail below.

FIG. 2 is a block diagram showing an embodiment of the light beam scanning device of the present invention, and the laser diode 1 in the figure is
Corresponding to the laser diode 101 in FIG. 6, the laser light emitted from the laser diode 1 in FIG. ) will be delivered to.

As shown in FIG. 2, the light beam scanning device of this embodiment includes a temperature detection element (therago star) 2, a set temperature selection section 3, an arithmetic control section 4, and an electronic cooling element (Peltier element).
5.

The temperature detection element 2 is for detecting the temperature of the laser diode 1, and is, for example, attached to a housing (not shown) in which the laser diode 1 is provided, and configured to detect the temperature of the housing. There is.

The set temperature selection section 3 is preset with a plurality of temperatures corresponding to a plurality of stable wavelength regions of the laser diode 1, which will be described later with reference to FIG. The closest set temperature is selected.

The configuration of the arithmetic control section 4 is the same as that of the conventional one, and includes subtraction sections 41, 42, 47. It includes an amplification section 43.45 and a current switching amplification section 44.46. In this calculation control unit 4, the laser diode l detected by the temperature detection element 5 is
, and the set temperature selected by the set temperature selection section 3 are compared, a predetermined control current is supplied to the electronic cooling element 5, and the laser diode 1 is heated or cooled.

Thereby, the temperature of the laser diode 1 is adjusted to match the set temperature selected by the set temperature selection section 3.

FIG. 3 is a diagram showing the temperature characteristics of a laser diode.

As shown in the figure, as the temperature of the laser diode 1 (temperature of the housing containing the laser diode 1) increases, its oscillation wavelength shifts to the longer wavelength side, and at a certain temperature, the oscillation wavelength shifts to the longer wavelength side. A sudden change (mode hop) is observed in the oscillation wavelength. Here, it is preferable that the temperature preset in the set temperature selection section 3 be set to a temperature approximately at the center of a region (wavelength stable region) in which wavelength fluctuations are small. In this way, the laser diode has a plurality of wavelength stable regions against temperature changes. specifically,
Typically, at the ambient temperature in which the light beam scanning device may be used (eg, 5-35° C.), the laser diode I, for example, has three wavelength stability regions. here,
The wavelength of the laser diode in these three wavelength stable regions is different, but in each wavelength stable region,
The wavelength is approximately constant within a range of plus or minus several degrees with respect to the center temperature (reference symbols ^, B, and C in FIG. 3).

As described above, the plurality of temperatures corresponding to the plurality of wavelength stable regions preset in the set temperature selection section 3 are indicated by the reference numeral A in FIG. This temperature corresponds to B and C.

FIG. 4 is a diagram for explaining the operation of the light beam scanning device of FIG. 2. As shown in the figure, in the light beam scanning device of this embodiment, in the set temperature selection section 3, for example,
Three temperatures A, B, and C corresponding to three wavelength stable regions are set in advance, and the temperature of the laser diode 1 (or the housing containing the laser diode) detected by the temperature detection element 2 such as a sustainer is The closest set temperature is selected. Specifically, if the detected temperature of the laser diode 1 is high, the set temperature C is selected, if the temperature of the laser diode 1 is room temperature, the set temperature B is selected, and if the temperature of the laser diode 1 is low, the set temperature C is selected. The set temperature A is selected.

Then, the temperature of the laser diode 1 (or the housing containing the laser diode) is selected by the set temperature selection unit 3 by a temperature variable element (electronic cooling element) 5 such as a Bertier element controlled by the arithmetic control unit 4. The temperature is adjusted to match the set temperature.

As a result, the laser diode 1 is brought up to a stable set temperature in a short time (specifically, the temperature closest to the temperature of the laser diode 1 among the set temperatures A, B, and C) and emits laser light with a stable wavelength. can be done. moreover,
Since the laser diode 1 is heated to a set temperature closest to the temperature of the laser diode, the power consumed by the electronic cooling element 5 for temperature adjustment can be minimized.

〔Effect of the invention〕

As described above in detail, the light beam scanning device of the present invention includes:
Multiple temperatures corresponding to multiple wavelength stability regions of the laser diode are set in advance, and the set temperature closest to the detected laser diode temperature is selected to match the temperature of the laser diode to the selected set temperature. By adjusting the temperature, the laser diode can be raised to a stable set temperature in a short time, and the power consumption required to raise the laser diode to the set temperature can be reduced.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the principle of the light beam scanning device according to the present invention, Fig. 2 is a block diagram showing an embodiment of the light beam scanning device according to the present invention, and Fig. 3 is a block diagram showing the temperature characteristics of the laser diode. 4 is a diagram for explaining the operation of the light beam scanning device shown in FIG. 2, FIG. 5 is a diagram showing an example of a conventional light beam scanning device, and FIG. 6 is a diagram showing an example of a conventional light beam scanning device. FIG. 7 is a diagram illustrating the operation of the light beam scanning device shown in FIG. 6, showing another example. (Explanation of symbols) 1... Laser diode, 2... Temperature detection means, 3... Set temperature selection means, 4... Arithmetic control means, 5... Temperature variable means. A diagram showing the temperature characteristics of a laser diode. A diagram explaining the operation of the light beam scanning device shown in Figure 2.

Claims (1)

[Claims] 1. A light beam scanning device using a laser diode (1) and a hologram element, comprising: temperature detection means (2) for detecting the temperature of the laser diode; and a plurality of wavelengths in the laser diode. set temperature selection means (3) for presetting a plurality of temperatures corresponding to stable regions and selecting the set temperature closest to the detected temperature of the laser diode; a calculation control means (4) which compares and calculates a preset temperature and outputs a predetermined control signal; Temperature variable means (5) for matching the selected set temperature
A light beam scanning device comprising: 2. The temperature detecting means includes a thermistor to detect the temperature of the housing containing the laser diode, and the temperature variable means includes a Peltier element to adjust the temperature of the housing. The optical beam scanning device described in .