JPH01313987A - Integration type laser unit - Google Patents

Abstract

PURPOSE:To enable mass production, and prevent the move, damage, fall-out, etc., of a hologram element by forming the hologram element in a square type, and providing a cover to envelope the hologram element. CONSTITUTION:The external shape of a hologram element 11 is square. The hologram element 11 is provided with a cover 12 to envelope the hologram element 11. By the way, the upper surface part of the cover 12 is provided with a window 12a to radiate and introduce laser light and reflected light from the outside, through the hologram element 11. Thereby, mass productivity is improved, and the move, damage and fall-out of the hologram element can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an integrated laser unit for optical pickup using a hologram element instead of a beam splitter as a beam splitting element.

<Prior Art> Recently, an integrated laser unit has been proposed in which a laser chip, a monitoring light receiving element, and a signal reading light receiving element are built into a cap or the like, and a hologram element as a light splitting element is integrated into this.

FIG. 3 shows a configuration diagram of a conventional integrated laser unit using a hologram element. l is the stem, 2 is the laser chip, 3 is the monitor light receiving element, 4 is the signal reading light receiving element, 5 is the cap (package), 6 is the cap 5
This is a hologram element directly attached to the top with adhesive or the like. As shown in FIG. 4, this laser unit A can constitute an optical pickup device simply by combining it with a collimating lens 7, an objective lens 8, and an actuator for driving the objective lens (not shown).

That is, the beam emitted from the laser chip 2 of the laser unit A passes through the hologram element 6, and its zero-order light passes through the collimator lens 7 and the objective lens 8, and enters the disk 9, which is a recording medium. The reflected beam modulated by the information recorded on the disk 9 passes through the objective lens 8 and the collimating lens 7 again, and enters the hologram element 6. In the hologram element 7, the primary light of the emitted beam is made incident on the signal reading light receiving element 4, such as a 4-split type. An error signal for the RF multiplied signal servo signal is obtained from the output signal from the signal reading light receiving element 4. In this way, the optical pickup device can be configured much more compactly and easily than the conventional optical pickup device using a beam splitter.

<Problems to be Solved by the Invention> In the conventional integrated laser unit using a hologram element, the hologram element 6 is attached to the cap 5 as shown in FIG.
is mounted directly on top of the

Therefore, if this laser unit is dropped or stress is applied from the outside, the hologram element 7 may move, be damaged, or fall off.

As described above, the hologram element 6 guides the laser beam to the light receiving element 4 for signal reading, and is mounted on the cap 5 with high precision. Therefore, slight movement, damage,
Falling off is not allowed, and if this happens, the signal will not be read out.

Furthermore, in order to prevent this kind of thing (particularly damage when dropped), it is proposed that the hologram element 4 be made circular to match the shape of the cap 5.

However, it is not easy to process the porogram element 6 into a circular shape, and it is not suitable for mass production.

The present invention has been made in view of the above-mentioned points, and it is an object of the present invention to provide an integrated laser unit that is excellent in mass production and in which the hologram element does not move, break, or fall off.

Means for Solving the Problems> The present invention provides an integrated laser unit that incorporates a laser chip, a monitoring light-receiving element, a signal reading light-receiving element, and further integrates a hologram element as a light splitting element. has a square shape, and a cover is provided to cover the square-shaped hologram element in parentheses.

<Function> With the above configuration, the hologram element can have a rectangular outer shape, making it highly suitable for mass production, and since the hologram element is covered with a cover, the hologram element will not be moved, damaged, or damaged even though the outer shape is square. An integrated laser unit that does not fall off can be obtained.

<Example> An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing one embodiment. l is stem, 2
is a laser chip, 3 is a monitor light receiving element, 4 is a signal reading light receiving element, 5 is a cap (package), 1
Reference numeral 1 denotes a hologram element, and the hologram element 11 here has a rectangular outer shape. 12 is a cover that covers this hologram element 11. The cover 12 is attached to cover the cap 5 as well, and of course there is a hologram element l! on the top surface of the cover. A window "12a" is provided through which laser light and reflected light from the outside are emitted and entered.

Note that the above-described hologram element 11 can be created by employing the following multi-lead cutting method. FIG. 2(A) shows a large number of hologram elements formed on a glass substrate, and half-etching is performed vertically and horizontally to separate each element. If it is divided along the vertical and horizontal half-etching using a roller, etc., the result will be as shown in Figure 2 (B).
A hologram element 11 of -element is obtained. 11
a is a diffraction grating line formed on one or both surfaces of the element glass by photoetching or the like.

Since the cover 12 is provided to cover the hologram element 11 in this way, the hologram element! ■It is protected from external stress and will not move or fall off even if it is dropped. Although the hologram element It has a rectangular outer shape, it is protected by the cover 12 and is free from damage such as chipping.

<Effects of the Invention> As described above, according to the present invention, a useful integrated laser unit can be provided in which a hologram element is integrated and the hologram element is protected from external stress.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing an embodiment of the present invention, Figure 2 (A)
(B) is a plan view showing an example of the production of the hologram element shown in FIG. 1, FIG. 3 is a perspective view showing a conventional example, and FIG. 4 is a sectional view showing an example of the configuration as a pickup. 208. Laser chip, 38. , light receiving element for monitor, 401. Light receiving element for signal reading, 5. . Cap, l 1. ,,hologram element. Agent: Patent attorney Kaji Sugiyama (2 others) 2nd v.
A (B) To 5 Figure 3 To 3 To Figure 4 1E ``D1'-

Claims (1)

[Claims] 1. In an integrated laser unit incorporating a laser chip, a monitoring light receiving element, a signal reading light receiving element, and further integrating a hologram element as a beam splitting element, the outer shape of the hologram element is a square shape, and the outer shape of the hologram element is a square shape. An integrated laser unit characterized by being provided with a cover that covers a shaped hologram element.