TWI335030B - Optical system and optical recording and/or reproducing appatauts using the optical system - Google Patents

Description

1335030 The following is a replacement page of the present invention. The invention relates to an optical system and an optical recording/reproducing apparatus using the optical system. [Prior Art]

[0002] In an optical disk drive, an optical recording/reproducing apparatus writes or reads information on a recording medium with a laser beam. Referring to the first drawing, the conventional optical recording/reproducing apparatus includes a light-emitting element 1, a collimator lens 2, an optical path changing device 3, an objective lens 4, a condensing mirror 5, and a light-receiving element 6. The light beam emitted from the light-emitting element 1 is collimated by the collimator lens 2 into a parallel beam which passes through the optical path changing device 3 = is condensed by the objective lens Φ: the focus recording medium 7, and is reflected by the recording medium 7 ·. This reflection is fused to the objective lens 4 and then turned by the optical path changing device 3 and focused on the light receiving element 6 via the condensing mirror 5. Wherein, when the light beam is reflected by the recording medium 7, it is modulated by the information recorded by the recording medium 7. After receiving the reflected light beam, the light selecting element 6 performs photoelectric conversion, and converts the information carried by the reflected beam into an electrical signal and delivers Processed by subsequent circuits. The light-emitting element 1 generally employs a laser diode (0003) for performing a writing or reading operation on a recording medium, and the ideal state is a parallel beam of circular cross-section, but in practice In applications, the laser beam emitted by the laser diode is not ideal. Referring to the second figure, the laser diode 10 emits a laser beam whose emission angle 0 1 in the horizontal direction is not equal to the emission angle 0 2 in the vertical direction, resulting in the laser beam. The beam has an elliptical cross section. Please refer to the third figure, the emission angle of the laser beam in the horizontal direction 0 1 and its vertical direction on the 094110594 form number Α0101 page 4 / 20 page 0993346856-0 1335030 099 September 28 The relationship between the emission angle 02 and the relative light intensity of the two directions is very large. For example, the maximum angle of 0 1 can only take 10 degrees on both sides of the optical axis, and the maximum angle of 0 2 can take 50 degrees on both sides of the optical axis. It is indicated that the long axis of the elliptical section of the laser beam is in the vertical direction and the short axis is in the horizontal direction. If the elliptical beam is directly concentrated on the surface of the optical disc to form an elliptical spot, it is very difficult to process the information on the optical disc and the processing of the reflected optical signal. To solve this problem, the conventional technique employs a circular collimating lens having an aperture angle which is the maximum horizontal emission angle of the laser diode 10, so that a circular cross-section beam (shaded portion) which satisfies the requirements can be produced. However, since the partial beam of the vertical emission angle is discarded, the utilization of light energy is low. In order to obtain a sufficiently clear signal, the laser diode: need to have a higher performance. Therefore, it is difficult to reduce the cost of the entire optical recording/reproducing apparatus. SUMMARY OF THE INVENTION [0004] In view of this, it is necessary to provide an optical system that can improve light utilization efficiency.

In addition, it is also necessary to provide an optical recording/reproducing apparatus employing the optical system. An optical system includes: a light source, a collimating lens, and a prism group; a divergent elliptical beam emitted by the light source is incident on the collimating lens, and is collimated by the collimating lens to become a parallel elliptical beam, the parallel An elliptical beam is incident on the prism group, and a long axis of the parallel elliptical beam emitted by the triad group is shortened to be equal to a minor axis thereof, and the triac group includes a first triad and a second prism. 1. The second three 稜鏡 respectively include a first surface and a second surface, and the parallel elliptical beam emitted by the collimating lens is perpendicularly incident on the first surface of the first prism, the parallel elliptical light 0993346856-0 094110594 Form No. A0101 Page 5 / Total 20 Pages 1335030 On September 28, 099, according to the positive replacement page beam, the long axis is shortened after the first prism is emitted, and the beam propagation direction changes, and is incident on the second again. a third turn that further shortens the long axis of the beam to be equal to its minor axis, and causes the beam to be emitted from the second surface of the second three turns so that the direction of propagation is opposite to the collimating lens The side of the outgoing beam Consistent.

An optical recording/reproducing apparatus comprising: an optical system, an optical path changing device, an objective lens, a condensing mirror, and a light receiving element. The optical system emits a parallel circular laser beam that is incident on the objective lens through the optical path changing device and is focused on the recording medium by the objective lens.

And reflected by the recording medium, the reflected beam passes through the objective lens and is turned by the optical path changing device to be incident on the condensing mirror, and is focused by the condensing lens on the light receiving element. The optical system includes: a light source, a collimating lens, and a triad group; the divergent elliptical beam emitted by the light source is incident on the collimating lens, and is collimated by the collimating lens to become a parallel elliptical beam. a parallel elliptical beam is incident on the three-turn group, and a long axis of the parallel elliptical beam emitted by the triangular prism group is shortened to be equal to a short axis thereof, and the triangular prism group includes a first triangular prism and a second triangular prism, the first The second triangular prisms respectively include a first surface and a second surface, and the parallel elliptical beam emitted by the collimating lens is perpendicularly incident on the first surface of the first triangular prism, and the parallel elliptical beam is from the first surface After the three-shot exit, the long axis is shortened, and the beam propagation direction is changed, and is again incident on the second three-turn, which further shortens the long axis of the beam to be equal to its minor axis, and causes the beam to self- The second surface of the second three turns is emitted such that its direction of propagation coincides with the direction of the outgoing beam of the collimating lens. [0008] Compared with the prior art, the above optical system adopts a triangular prism group, the 094110594 form number A0101 page 6 / total 20 pages 0993346856-0 1335030 099 September 28th shuttle is replacing the page two pairs The long axis of the parallel elliptical beam is compressed such that its major axis is equal to the minor axis, thereby converting the parallel elliptical beam into a parallel circular beam. It makes full use of the light energy of the light beam emitted from the light source, and can reduce the cost of the optical recording/reproducing apparatus using the optical system. [Embodiment]

Please refer to the fourth (a) and fourth (b) drawings, which are views of the optical system 11 in the horizontal and vertical directions according to an embodiment of the present invention. The optical system 11 includes a laser diode 111, a collimating lens 112, a first three-turn 113 and a second three-turn 114. The four optical elements are sequentially disposed in the optical path in the order of the laser diode 111, the collimating lens 112, the first three-thirds 3, and the second three-turn 114. In the middle, the first main 113 And the second three turns 114 can be the same; the oxygen beam into the seven collimating lens 112 of the exiting beam sequentially passes through the first surface η 6 of the first three 稜鏡 11 3 and the second surface 117, and then through the second three The first surface 118 and the second surface 119 of the layer 14. The first surface 116 of the first three turns is perpendicular to the outgoing beam of the collimating lens 112, the second surface in is at an acute angle 03 with the -t- angle of the first surface 116, and the second triangular prism 114 is A surface 118 is perpendicular to the exit beam ' of the first three turns 113 and the second surface 119 is at an acute angle 04 to the first surface 118 thereof, and 03 and 04 are equal in size and respectively located on opposite sides of the parallel beam path . [0010] The short axis of the elliptical beam emitted by the laser diode 111 is located on a horizontal plane, which is the horizontal direction of the laser beam, and the long axis of the elliptical beam emitted by the laser diode 111 is located on the vertical plane. Is the vertical direction of the laser beam. [0011] Please refer to the fourth (a) diagram, in the horizontal direction, by the laser diode ill 094110594 Form No. A0101 Page 7 / Total 20 Page 0993346856-0 1335030 [0012] [0999 September 28 The divergent elliptical beam from the daily correction replacement page 1 is collimated by the collimating lens 112 to become a parallel elliptical beam and incident on the first three turns 113. Since the first surface 116 and the second surface 117 of the first three-turn U3 in the horizontal direction are perpendicular to the incident parallel beam, the parallel elliptical beam does not change after passing through the first three-turn U3, and is incident to The second three is 114. The parallel beam is once refracted at the first surface 118 of the second dipole 114 and another refraction occurs at its second surface - 119. Since the first surface 118 and the second surface 119 of the second three turns 114 are parallel to each other, the propagation direction of the light beam 1153 emitted by the second three turns 114 and the propagation direction of the light beam emitted from the collimator lens U2. Consistent and equal in width ^ ® See the fourth (b) diagram. In the vertical direction, the divergent elliptical beam emitted by the laser diode ill is first passed through the collimating lens 1.1 2-quasi And incident on the first three 113. Since the first surface 116 of the first triple 113 is perpendicular to the parallel elliptical beam and the second surface u 7 has an oblique angle to the parallel elliptical beam, the parallel elliptical beam passes normally through the first surface 116 and in the second The surface 117 is reflected and the long axis width of the parallel elliptical beam is reduced. Since the first surface 118 of the second triangular prism 114 is perpendicular to the outgoing beam of the first three pupils 113 and the second surface 119 has an oblique angle to the beam, the parallel elliptical beam emitted by the first triangular prism 113 is normal. The second surface 119 is refracted by the first surface 118. The direction of propagation of the light beam 115b emitted by the second three turns 114 coincides with the direction of propagation of the outgoing beam of the collimating lens 112, and the width is reduced to be equal to the above-described light beam 115a. Since the outgoing beam 1153 of the optical system 水平 in the horizontal direction is equal to the width of the outgoing beam 115b of the optical system 11 in the vertical direction. Therefore, form number A0101 Page 8 of 20 0993346856-0

[0013] 094110594 1335030 The original laser is emitted from the polar body 111 and collimated by the collimating lens 112, and the parallel elliptical modified circular beam is processed by the optical system to be converted into a parallel circular beam, and is not The loss of light energy is caused, and the luminous power of the laser diode 111 can be lowered.

[00M] Referring to FIG. 5, which is an optical recording/reproducing apparatus (not shown) employing the optical system described above, comprising: the optical system 11, an optical path changing device 12, an objective lens 13, and a condensing mirror 14, A light receiving element 15. A parallel circular laser beam is emitted by the optical system 11, and the parallel laser beam is incident on the objective lens 13 via the optical path changing device 12, is focused on the recording medium 16 by the objective lens 13 and is reflected back by the recording medium 16, which After the reflected beam passes through the objective lens 13, it is rotated by the optical path to change the ritual 12 into the condensing mirror 14, ..., v ''., . . . is focused by the condensing mirror η on the light receiving element: the element 15 is broken It sucks and converts to -3⁄4. - > ^ —_ ...\ ; . _; electrical signals for subsequent signal processing operations. Since the parallel elliptical beam emitted by the laser diode 111 and collimated by the collimating lens 112 in the optical system 11 is processed by the first three 113 and the second triple 114, the parallel elliptical beam is made. The width is shortened in the vertical direction to

The widths in the horizontal direction are equal, thereby converting the parallel elliptical beam into a parallel circular beam with no loss of light energy. Therefore, the light-emitting power of the laser diode 111 can be lowered, and the optical system of the optical system is used. The recording/reproducing device (not shown) has improved work efficiency and reduced cost. [0015] In summary, the present invention complies with the requirements of the invention and submits a patent application according to law. It is to be understood that the above-mentioned preferred embodiments of the present invention are intended to be included within the scope of the appended claims. [Simple description of the drawing] 094110594 Form No. A0101 Page 9 of 20 0993346856-0 1335030 Correction replacement page of September 28, 2008 [0016] The first figure is a schematic structural view of a conventional optical recording/reproducing apparatus. [0017] The second figure is a schematic diagram of a general laser diode emitting an elliptical beam. [0018] The third figure is a schematic diagram showing the relationship between the light emission angles of the elliptical beams emitted by the laser diodes and the relative light intensities in the vertical and horizontal directions. [0019] The fourth (a) diagram is a horizontal view of the optical system provided by the present invention. [0020] The fourth (b) diagram is a vertical view of the optical system provided by the present invention. [0021] The fifth drawing is a schematic view showing the structure of an optical recording/reproducing apparatus using the optical system of the present invention. [ [0022] [Description of main component symbols] -..., optical system: 11 _ .-V . η .·,,,..,, .'·· [0023] Collimating lens: 2, 112 [0024] The second three 稜鏡: 114 [0025] Objective lens: 4, 13 [0026] Light receiving element: 6, 15 _ [0027] Light source: 1,111 [0028] First three: 113 [0029] Light path change Apparatus: 3, 12 [0030] Condenser: 5, 14 [0031] Recording medium: 7, 16 [0032] First surface: 116, 118 094110594 Form number Α 0101 Page 10 / Total 20 pages 0993346856-0 1335030 [0033] Second surface: 117, 119 September 28, 2010, according to the replacement page

Lu 094110594 Form No. A0101 Page 11 of 20 0993346856-0

Claims (1)

1335030 Modified on September 28, 2008. Replacement page 7. Patent application scope: 1. An optical system comprising: a light source to generate a divergent elliptical beam; a collimating lens to collimate the light beam from the light source The collimated beam is a parallel elliptical beam; a three-turn group for shortening a long axis of a parallel elliptical beam aligned by the collimating lens to be equal to a minor axis thereof, the triac group comprising a first three-turn and a second triangular prism, The first and second prisms respectively include a first surface and a second surface, and the parallel elliptical beam emitted by the quasi-true lens is perpendicularly incident on the first surface of the first three turns, and the parallel elliptical beam is from the first After the first prism is emitted, the long axis is shortened" and the beam is broadcasted: the agricultural direction is changed, and is again incident on the second three turns, the second three stupid 'lock; 'the beam long axis is further shortened to The optical axis of the first embodiment is the same as the short axis of the collimating lens. The optical system of claim 1, wherein the first triangular edge The first surface of the mirror is perpendicular to the incident beam and the first surface of the second triangular mirror is perpendicular to the incident beam and the optical surface of the second triangular mirror is perpendicular to the incident beam. An optical system according to the third aspect of the invention, wherein the first surface of the first three turns is at an angle with the second surface and the first surface of the second three turns The angle between the second surfaces is on opposite sides of the optical path. 5. The optical system of claim 4, wherein the first triangular prism is the same material as the second triangular prism. 094110594 Form No. A0101 Page 12 of 20 0993346856-0 1335030 </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; The angle between the two surfaces is equal to the angle between the first surface of the second three turns and the second surface thereof. 7. An optical recording/reproducing device comprising: An optical system comprising a light source for generating a divergent elliptical beam, a pair of collimating lenses collimating the beam from the source, and a short axis of the parallel elliptical beam exiting the collimating lens is shortened to An equal set of prisms, the prism set including a first three and a second three, the first and second prisms respectively comprising a first surface and a second surface, wherein the collimating lens The emerged parallel elliptical beam is perpendicularly incident on the first surface of the first three turns, the parallel elliptical beam is elongated from the first triangular prism, and the long axis is shortened, and the beam propagation direction is changed, and is incident on the second triangular edge again. a second prism that further shortens the long axis of the beam to be equal to its minor axis and has a direction of propagation that coincides with the direction of the outgoing beam of the collimating lens; an optical path changing device to cause the optical system to exit The light beam passes normally, and the optical path of the reflected beam of the recording medium is changed; An objective lens for focusing an outgoing beam of the optical path changing device on a recording medium and normally transmitting a reflected beam of the recording medium; a condensing mirror for focusing a light beam that changes an optical path by the optical path changing device; and a light receiving element A light beam from the concentrating mirror is received. 8. The optical recording/reproducing apparatus of claim 7, wherein the first surface of the first prism is perpendicular to the incident beam and at an acute angle to the second surface thereof. 9. The optical recording/reproducing apparatus of claim 8, wherein the first surface of the second three turns is perpendicular to the incident beam and has an acute angle with the second surface thereof. 094110594 Form No. A0101 Page 13 of 20 pages 0993346856 -0 1335030 On September 28, 099, the page was replaced. 10. The optical recording/reproducing apparatus of claim 9, wherein an angle between the first surface of the first triangular prism and the second surface thereof and an angle between the first surface of the second triangular prism and the second surface thereof are located in the optical path Opposite sides. 11. The patented scope 1st record/reproduction device, wherein the first three turns are the same material as the second triangular prism. 12. The optical recording/reproducing apparatus of claim 11, wherein an angle between the first surface of the first triangular prism and the second surface thereof is equal to an angle between the first surface of the second triangular prism and the second surface thereof. 094110594 Form No. A0101 Page 14 of 20 0993346856-0