CN1075221C - Head device - Google Patents
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- CN1075221C CN1075221C CN96122858A CN96122858A CN1075221C CN 1075221 C CN1075221 C CN 1075221C CN 96122858 A CN96122858 A CN 96122858A CN 96122858 A CN96122858 A CN 96122858A CN 1075221 C CN1075221 C CN 1075221C
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Abstract
The present invention provides an optical head device capable of easily obtaining accuracy with easy working, averting the increase in manufacturing cost and the increase in size and the degradation of using efficiency of the light beam and eliminating the need for the labor for special assembly. This head device has an objective lens 2, a light source 3 consisting of, for example, a laser diode and other optical elements 4, 5. The front surface of the optical element, for example, collimator lens 5, etc., which has a curved surface gentler than the surface of the objective lens 2 and has an intrinsic function is provided with a hologram 4 having a function to focus the beam transmitted through the objective lens 2 to a position F' different from the position F of the focus of the objective lens 2.
Description
The present invention relates to be assembled into the optical-head apparatus of optical disc apparatus etc.In more detail, the present invention relates to light beam that a light source is come with the bifocus optical-head apparatus of an object lens focusing in two places.
As digital recording medium CD and DVD (digital video disk), with in thickness and the optical disc apparatus that different multiple CDs such as recording density are reset, for the various CDs of resetting, being necessary must be corresponding with each CD with the conversion such as size of the focal position of laser and luminous point.For this reason in the existing optical-head apparatus that uses, for example special public clear 54-19329 number and spy of Jap.P. opens shown in flat 5-303766 number, and the optical element that is used for revising the aberration that produces when the object lens of being used by a kind of optical disk data reproducing are reset another kind of CD can be put into the light path of the optical system from the light source to the CD or take out.
And, there is a kind of optical-head apparatus that can replace the different object lens of two focuses of installation also to come out.The corresponding CD of resetting of this optical-head apparatus is replaced and is used each object lens.
Also develop on the surface of light source one side of object lens the optical-head apparatus that focuses on the locational holographic lens (hologram) different with the focal position of object lens is set.Develop the optical disc apparatus that has the holographic element plate that makes the function that the light beam through object lens focuses on the position different with the focal position of these object lens nearby setting of light source one side of object lens again.In these optical-head apparatus, focused on respectively by the diffraction light of holographic lens diffraction and not diffracted non-diffracted light, on same optical axis, form two focuses.Thereby, each beams focusing position is positioned on the record surface of CD of corresponding kind, just can reset to this CD.
But, the optical-head apparatus that the optical element that the aberration correction is used in the light path of optical system can be put into, take out, except the original necessary MIN optical element of optical-head apparatus, the mechanism that optical element must be set and this optical element is put into, taken out also.And, on objective lens support, there is the optical-head apparatus of two object lens that the replacement mechanism of the 2nd object lens and each object lens must be set.Moreover the optical-head apparatus that nearby sets the holographic element plate at object lens is necessary to set the holographic element plate.Therefore, the number of parts of these optical-head apparatus has increased, thereby causes the manufacturing expense of optical-head apparatus to increase and maximization.And the putting into of optical element, withdrawing device and object lens alternative also have the unsettled situation of action.
And owing to must carry out position adjustment and optical axis adjustment to optical element and the 2nd object lens, the holographic element plate that the aberration correction that increases newly is used, it is miscellaneous that assembly working becomes.Therefore, manufacturing cost increases more, assembles, adjusts time taking problem simultaneously in addition.
On the other hand, under the situation of the whole formation of objective lens surface holographic lens,, there are problems such as difficult processing, precision are not high because the surface curvature of light source one side of object lens is big.
And nearby setting in the optical-head apparatus of holographic element plate of object lens, the light beam of CD reflection sees through holographic lens once again.Therefore, beam reflected a part of diffracted left light path, can not inject photo detector.Therefore produced the low problem of light beam utilization ratio.
The object of the present invention is to provide easy processing, easily obtain high precision, again do not increase manufacturing expense, can not cause device to maximize, and do not need to assemble especially the bifocus optical-head apparatus of formality.
Purpose of the present invention is to provide the utilization ratio that does not reduce light beam again, and processes, obtains easily high-precision bifocus optical-head apparatus easily.
Optical-head apparatus of the present invention, possess: object lens, light source, surface configuration for than described object lens towards the optical element on the surperficial mild curved surface of light source one side or plane and be formed at this optical element surface, section is jagged a plurality of concentric circles grid, has the holographic lens (hologram) of the function that makes the light beam focusing that sees through described object lens on the position different with the focal position of described object lens.
Fig. 1 is the concept map of optical system of the 1st embodiment of expression optical-head apparatus of the present invention.
Fig. 2 is the semi-section stereographic map of the holographic lens of expression optical-head apparatus setting of the present invention, (a) is the holographic lens with concavees lens function, (b) is the holographic lens with convex lens function, (c) is the holographic lens with function of concavees lens and convex lens.
Fig. 3 is the concept map of optical system of the 2nd embodiment of expression optical-head apparatus of the present invention.
Fig. 4 is the concept map of optical system of the 3rd embodiment of expression optical-head apparatus of the present invention.
Fig. 5 is the concept map of optical system of the 4th embodiment of expression optical-head apparatus of the present invention.
Fig. 6 is the concept map of optical system of the 5th embodiment of expression optical-head apparatus of the present invention.
Fig. 7 is the concept map of optical system of the 6th embodiment of expression optical-head apparatus of the present invention.
Fig. 8 is the concept map of optical system of the 7th embodiment of expression optical-head apparatus of the present invention.
Fig. 9 is the concept map of optical system of the 8th embodiment of expression optical-head apparatus of the present invention.
Figure 10 is the concept map of grating among the 9th embodiment of expression optical-head apparatus of the present invention.
Figure 11 be the expression optical-head apparatus of the present invention the 10th embodiment in light source and glass cover-plate near concept map.
Embodiment shown in reference to the accompanying drawings is elaborated to structure of the present invention below.
The 1st embodiment
As shown in Figure 1, the optical-head apparatus 1 of the present invention the 1st embodiment possesses: object lens 2, the light source 3 and other optical elements 5,41 that are made of for example laser diode.Collimation lens 5 is that surface configuration is the optical element than the surperficial mild curved surface of object lens 2.Holographic lens 41 has the light beam that makes through these object lens 2 and focuses on the different position F of position F with the focus of object lens 2
-On function.This holographic lens 41 is formed at the surface of collimation lens 5 towards light source 3 one sides.
In the present embodiment, the optical element beyond object lens 2 and the light source 3 has: be disposed at collimation lens 5 between object lens 2 and the light source 3, be arranged at these collimation lens 5 surfaces holographic lens 41, be disposed at the semi-transparent semi-reflecting lens that between light source 3 and the collimation lens 5, not shown, receive photo detector this semi-transparent semi-reflecting lens beam reflected, not shown.Also it doesn't matter between collimation lens 5 and the object lens 2 and even semi-transparent semi-reflecting lens is configured in.Also have, light source 3 uses laser diode, but is not limited to this, also can use other light-emitting components.
The shape of collimation lens 5 is taked, and does than the little shape of surface curvature towards object lens 2 one sides towards the surface curvature of light source 3 one sides.Surface configuration towards light source 3 one sides is that the plane is also passable.The holographic lens 41 that has the concavees lens function on the surface of these light source 3 one sides is made with collimation lens 5 monolithic moldings.These collimation lens 5 usefulness are being shaped with casting mold of plastics or glass etc. for example.Here, holographic lens 41 is formed on the little curved surface of curvature, so the metal die that casting mold is used manufactures high precision easily.Also have, holographic lens 41 can be not and collimation lens 5 monolithic moldings yet.For example, after making collimation lens 5 with glass etc., stick the holographic lens 41 that plastics make on the surface of this collimation lens 5 good.
Again, each grid of holographic lens 41 is the more little periodic modulation type of central portion grid cycle that leaves collimation lens 5 more, therefore, can make by the light beam of holographic lens 41 diffraction CD 6,6 ' record surface on aberration reduce.Can also change the angle of beam spread by means of the average grid cycle of change holographic lens 41.Therefore ,-1 order diffraction light is changed by the position that object lens 2 focus on.And the height of grid of change holographic lens 41 just can change the balance of the light quantity of-1 order diffraction light and not diffracted 0 grade of light.
The light beam that light source 3 produces sees through the not shown half-reflecting half mirror that goes out, and becomes parallel beam by collimation lens 5 flexions.Here, see through in the light beam of holographic lens 41,0 grade of light also becomes parallel beam.This parallel beam is injected object lens 2, through optically focused, focuses at the position F of the focus of these object lens 2.Meanwhile, the part of the light beam of light source 3 generations becomes-1 order diffraction light by holographic lens 41 diffraction.Should-1 order diffraction light since collimation lens 5 acted as the light beam that spreads apart some than directional light.This light beam is assembled through object lens 2, at the position F than the focal position F predetermined distance only far away of object lens 2
-Focus on.
With 1 pair of CD 6 of described optical-head apparatus, 6 ' playback time, to the CD 6,6 reset ' thickness detect after, make optical-head apparatus 1 near CD 6,6 '.Focusing position F at the light beam of holographic lens 41 diffraction
-When being positioned at record surface, measure the 1st focusing.Here, if CD 6 ' be thick, optical-head apparatus 1 just stops to move, Here it is can the reset state of phonotape and videotape.If CD approaches, just make optical-head apparatus 1 further near CD 6.And when being in record surface, measure the 2nd focusing without the focal position F of the lens 2 of the light beam of holographic lens 41 diffraction focusing.Here, the mobile of optical-head apparatus 1 stops, Here it is can reset the phonotape and videotape state.
With the optical-head apparatus 1 of present embodiment, when being installed in the optical disc apparatus of can reset for example CD and DVD, the result is as follows.CD thickness is 1.2 millimeters, and the wavelength of light source is 780 millimicrons, and object lens NA (numerical aperture) is 0.45.DVD thickness is 0.6 millimeter, and the wavelength of light source is 650 millimicrons, and object lens NA is 0.60.Here, if in order to be used for DVD, be about 650 millimicrons with the wavelength set of the light source 3 of present embodiment, then when carrying out the reading of CD,, object lens NA can be shortened to 0.38 corresponding to the short partially amount of wavelength.Therefore, needn't go up in the whole effective aperture of collimation lens 5 (the light beam scope of solid line among the figure) and form holographic lens 41, and near scope formation holographic lens only central authorities, that be equivalent to NA=0.38 gets final product.And, then change size with respect to the holographic lens 41 of the effective aperture of collimation lens 5 according to the NA value for the playback of other kind CDs.For example, the playback for the CD of NA that need be bigger than DVD also has the situation that forms holographic lens 41 on the whole effective aperture of collimation lens 5.
Adopt present embodiment, the light beam flexion of diffusion to become on the collimation lens 5 of parallel beam holographic lens 41 is set, therefore, do not dispose the optical element of the such function of having only holographic lens of holographic element plate.So can reduce number of parts, also reduce manufacturing expense.And, by means of the position of adjusting collimation lens 5, can adjust the position of holographic lens 41 simultaneously.Therefore, work is adjusted in the position that does not need to carry out holographic lens 41, and the assembling of optical-head apparatus 1 can be carried out rapidly.
The foregoing description is one of most preferred embodiment of the present invention, but the invention is not restricted to this, but the possibility that in the scope that does not exceed main idea of the present invention, has various distortion to implement.For example, holographic lens 41 is made the holographic lens with convex lens function, or make not only have the concavees lens function but also have a holographic lens of convex lens function good.Also holographic lens 41 can be arranged on collimation lens 5 optical element in addition.The following describes the shape of change holographic lens 41 and other embodiment that the installation site obtains.But, be not limited to these embodiment certainly.Also have, in the explanation of embodiment below, the parts with identical functions use identical symbol, omit its detailed description.
The 2nd embodiment
As shown in Figure 3, the holographic lens 42 with convex lens function is formed on the face of collimation lens 5.This holographic lens 42, shown in Fig. 2 (b), possessing section is jagged a plurality of concentric circles grid 42a, and the structure of each grid 42a is, each inner peripheral surface forms the periphery 42c that is parallel to optical axis S, and outer circumference surface forms the center precipitous more ring-type dip plane 42b far away more that leaves holographic lens 42.And, form the conus portion 42d that ring-type dip plane 42b heaves slightly at the center of holographic lens 42.On one side this holographic lens 42 by the light beam of this holographic lens diffraction+only allow in 1 order diffraction light and-1 order diffraction bring together inject object lens 2+generation of 1 order diffraction light.Therefore, the light beam of injecting holographic lens 42 under the situation of diffraction by light harvesting.This diffraction light than the focal position F of object lens 2 more near the position F of these object lens 2
+Focusing.Adopt the 2nd embodiment, do not make and dropped on the record surface of thick CD 6 by the focal position of the light beam of holographic lens 42 diffraction focusing, and the position F that diffracted light beam is focused
+Drop on glimmer dish 6 ' record surface on, with carry out each CD 6,6 ' playback.
Also have, the holographic lens 41 of concavees lens function will be had among above-mentioned the 1st embodiment, in the 2nd embodiment, be that the holographic lens 42 that will have a convex lens function is formed at the form on the face of collimation lens 5, but also can form the holographic lens 43 that has concavees lens function and convex lens function simultaneously on the surface of optical element.This holographic lens 43, shown in Fig. 2 (c), possessing section is a plurality of concentric circles grid 43a of rectangle.Each grid 43a, its outer circumference surface 43b separately and inner peripheral surface 43c form as the periphery parallel with optical axis S, its radially width and the spacing between the grid 43a, far away more just more little from the center of holographic lens 43.And in holographic lens 43, be formed centrally columnar portion 43d.This holographic lens 43 produce by the light beam of these holographic lens 43 diffraction+two kinds of 1 order diffraction light and-1 order diffraction light.Thereby these diffraction lights are assembled by object lens 2, and-1 order diffraction light is at the position F than the focal position F of object lens 2 predetermined distance only far away
-Focusing ,+1 order diffraction light than the focal position F of object lens 2 also near the position F of these object lens 2
+Focusing.Make the different CD of thickness corresponding to different each focal position F, F like this
-, F
+, make multiple CD can use a kind of common device to reset.
The 3rd embodiment
In the 3rd embodiment, as shown in Figure 4, the holographic lens 41 with concavees lens function is set at the surface to object lens 2 one sides of the object lens 2 of collimation lens 5.Holographic lens 42 with convex lens function also can be set or have concavees lens and the holographic lens of convex lens function 43 replacement holographic lenses 41.Adopt present embodiment, when making 5 of collimation lenses be held in not shown lens carrier, even install towards the little side of the surface curvature of light source 3 one sides, holographic lens 41 can not influence lens carrier yet, and installment work is carried out easily.
In the 4th embodiment, as shown in Figure 5, the cubical beam splitter of light path fork means (the beam splitter) 7 that is configured between object lens 2 and the collimation lens 5 is provided with the holographic lens 41 with concavees lens function on a side surface of object lens 2.These cubical beam splitter 7 inside possess the reflecting surface 7a of partial reflection light beam, have and the half-reflecting half mirror identical functions.Also have, the holographic lens 42 with convex lens function also can be set or have concavees lens and the holographic lens of convex lens function 43 substitutes holographic lens 41.And, even it is also passable towards a side surface of light source 3 holographic lens 41 to be set at beam splitter 7.Adopt this embodiment, because the surface of beam splitter 7 is the plane, holographic lens 41 forms easily.
The 5th embodiment
In the 5th embodiment, as shown in Figure 6, configuration polarization beam splitter 8 and 1/4 wavelength plate 9 between collimation lens 5 and object lens 2.Then at the holographic lens 41 that has the concavees lens function towards a side setting of object lens 2 of 1/4 wavelength plate 9.Holographic lens 42 with convex lens function also can be set or have concavees lens and the holographic lens of convex lens function 43 replacement holographic lenses 41.Holographic lens 41 can also be arranged on the surface of optical axis S of polarization beam splitter 8.
In the present embodiment, see through collimation lens 5 rectilinearity polarized light light beam almost see through polarization beam splitter 8 all.This light beam becomes circularly polarized light when seeing through 1/4 wavelength plate 9.And a part of light beam is by holographic lens 41 diffraction.Also have, light beam in CD 6,6 ' reflection, is seen through object lens 2 by the focusing of object lens 2 light harvestings once again.This folded light beam becomes the rectilinearity polarized light after seeing through 1/4 wavelength plate 9.Therefore, in the inside of polarization beam splitter 8, incident beam and folded light beam be phasic difference 90 degree mutually.Folded light beam almost all is polarized beam splitter 8 reflections, injects the light emitting diode of not shown detection usefulness.Present embodiment is fit to be used in and can writes type CD and DVD owing to the utilization ratio height of light beam.Because the surface of polarization beam splitter 8 and 1/4 wavelength plate 9 is planes, form holographic lens 41 easily again.
At embodiment 6, as shown in Figure 7, make the optical axis S of light source 3 and collimation lens 5 and the optical axis S quadrature of object lens 2, on the intersection point of each optical axis S configuration becomes with each optical axis S 45 degree inclinations the completely reflecting mirrors formation to upper reflector 10.Then, the holographic lens 41 with concavees lens function is being set on the reflecting surface of upper reflector 10.Holographic lens 42 with convex lens function also can be set or have concavees lens and the holographic lens of convex lens function 43 replacement holographic lenses 41.Set not shown half-reflecting half mirror again at collimation lens 5 with between upper reflector 10.
Adopt this embodiment, from light source 3 to CD 6,6 ' the optical axis complications that meet at right angles, therefore, can make perpendicular to CD 6,6 ' direction on the thickness of optical-head apparatus 1 reduce.Therefore, can seek the miniaturization of optical-head apparatus.Again owing to being planes, so holographic lens 41 forms easily to the surface of upper reflector 10.Can also be arranged at the holographic lens 41 of present embodiment on the minute surface of plate half-reflecting half mirror or polarization beam splitter.
The optical-head apparatus 1 of above-described the 2nd to the 6th embodiment also can reduce number of parts, do not need to adjust the position of holographic lens 41 (42,43) again, and, can reduce manufacturing expense because holographic lens 41 (42,43) is arranged on plane or the mild curved surface, accelerate assembling speed.
The optical-head apparatus 1 of the present invention the 7th embodiment as shown in Figure 8, possesses object lens 2, light source 3 and inner for example cubical beam splitter 7 with reflecting surface 7a, has the light beam that sees through object lens 2 is focused in the position F different with the focal point F of these object lens 2
-The holographic lens 41 of function be set between beam splitter 7 and light source 3, optical element beam splitter 7 is towards the surface of light source 3 one sides.
The beam splitter 7 of present embodiment can be used, on the one hand the light beam of light source 3 is partly seen through, on the other hand with reflecting surface 7a partial reflection from CD 6 inflection light, guide it half-reflecting half mirror of photo detector into, also can use, the composition (P composition) that is parallel to the plane of incidence is intactly seen through, and reflect the polarization beam splitter of vertical composition (S composition) with reflecting surface 7a.And between light source 3 and beam splitter 7, set the glass cover-plate (protection use transparent panel) 12 of protection light source 3.The divergent beams flexion that configuration is sent light source 3 between beam splitter 7 and object lens 2 becomes the collimation lens 5 of parallel beam.The surface towards a side of light source 3 at beam splitter 7 forms the holographic lens 41 with concavees lens function with beam splitter 7 global formations.These beam splitter 7 usefulness for example die casting such as plastics or glass form.Here, because holographic lens 41 is formed on the plane, the metal die that die casting is used can be made high precision.And holographic lens 41 can be not and beam splitter 7 global formations yet.For example, also can stick on the surface of this beam splitter 7 with the holographic lens 41 that glass etc. is made behind the beam splitter 7 the plastics manufacturing again.
The shape of each grid 41a of holographic lens 41, identical with the embodiment that has illustrated, have the shape shown in Fig. 2 (a), but also can make Fig. 2 (b) (c) shown in the holographic lens 42,43 of structure replace holographic lenses 41.Each grid 41a is that cycle of grid on beam splitter 11 surfaces is from optical axis S more little periodic modulation type far away more.Therefore, the aberration of the luminous point of light beam on the record surface of CD 6 of holographic lens 41 diffraction can reduce.Also change the angle of beam spread by means of the average grid cycle that changes holographic lens 41.Thereby the position that-1 order diffraction light is assembled through object lens 2 is changed.Again by means of the height of the grid 41a that changes holographic lens 41, can change-1 order diffraction light and the light quantity balance between 0 grade of light of diffraction not.
The light beam that is produced by light source 3 sees through glass cover-plate 12 while spreading.This diffusion light is intrafascicular do not see through the light beam of holographic lens 41 and see through but not 0 of diffraction grade of light beam inject beam splitter 7 while scattering.At beam splitter 7, most of penetration face 7a of light beam injects collimation lens 5.This light beam becomes parallel beam in collimation lens 5 flexions.This parallel beam is injected object lens 2 by optically focused, assembles at the focal position of these object lens 2 F.
On the other hand, see through a part of light beam diffracted becoming-1 order diffraction light of holographic lens 41.While should spread transmitted beam separation vessel 11 by-1 order diffraction light,, become the light beam that scatters slightly than directional light through collimation lens 5 flexions.This light beam focuses on through object lens 2, at the position F than the distant place of the focal position F predetermined distance only far away of object lens 2
-Focus on.
The light beam that focuses at position F is reflected by thin CD 6, at position F
-The light beam that focuses on is by thick CD 6 ' reflection.These folded light beams see through object lens 2 and collimation lens 5, on one side optically focused inject beam splitter 7 on one side.The be reflected face 7a reflection of the part of incident beam is injected photo detector 13 through optically focused.
Adopt the 7th embodiment, CD 6,6 ' beam reflected are injected photo detector 13 through object lens 2, collimation lens 5 and beam splitter 7.Therefore, folded light beam does not see through holographic lens 41, so unnecessary diffraction does not take place.Thereby in the light beam that light source 3 takes place, the light quantity that arrives the light beam of photo detector 13 increases, so can improve the utilization ratio of light beam.
And on light beam beam splitter 7 along separate routes, holographic lens 41 is being set, and therefore, there is no need to be provided with in addition the optical element that has only the holographic lens function as the holographic lens element board, only this just can reduce number of parts, also reduces manufacturing expense.Also have, when the position of beam splitter 7 was adjusted, the position of holographic lens 41 also obtained adjusting simultaneously.Therefore, do not need the position of holographic lens 41 is adjusted, the assembling of optical-head apparatus 1 can be carried out rapidly.The 7th embodiment is one of most preferred embodiment of the present invention, but the invention is not restricted to this, but the possibility that in the scope that does not exceed main idea of the present invention, has various distortion to implement.For example, change holographic lens 41 into holographic lens 42, or not only had the convex lens function but also had a holographic lens 43 of concavees lens function good with convex lens function.Holographic lens 41 (42,43) can be arranged at again on beam splitter 7 optical element in addition.The following describes the shape of change holographic lens 41 and other embodiment that the installation site obtains.But, be not limited to these embodiment certainly.
Embodiment 8
The 8th embodiment as shown in Figure 9, forms the holographic lens 42 with convex lens function at beam splitter 7 towards a side surface of light source 3.This holographic lens 42 by the light beam of these holographic lens 42 diffraction+1 order diffraction light and-1 order diffraction light in, only make on one side bring together inject object lens 2+generation of 1 order diffraction light.Therefore, the light beam of injecting holographic lens 42 when diffraction by light harvesting.This diffraction light than the focal position F of object lens 2 more near the position F of object lens 2
+Assemble.Adopt the 8th embodiment, the focal position F that is not focused on by the light beam of holographic lens diffraction is dropped on the record surface of thick CD 6, the focal position F that diffracted beam focuses on
+Drop on glimmer dish 6 ' record surface on, with this each CD 6,6 of can resetting '.
Embodiment 9
The 9th embodiment as shown in figure 10, is being provided with the holographic lens 41 with concavees lens function with surface as the opposite side of grid face of the grating 14 of diffraction grating.Holographic lens 42 with convex lens function also can be set or have concavees lens and the holographic lens of convex lens function 43 replacement holographic lenses 41.Grating 14 is arranged between glass cover-plate 12 and the beam splitter 11, with the grid face that diffraction grating is arranged be towards CD 6,6 ' a side.Again, the grid face of grating 14 also can reverse configuration with the face that possesses holographic lens 41.Also have, beam splitter 7 also is not limited to cubic type, also can be tabular.
Grating 14 forms the secondary luminous point of the front and back of the track direction that is positioned at the luminous point that object lens 2 form.That is grating 14 is restrainted the light beam that light source 3 sends by having the diffraction of denying or angle of diffraction to be divided into 3.Then, the luminous point with central light beam formation playback usefulness forms secondary luminous point with other two bundles side beams.The luminous point that uses this 3 light beams to form can carry out tracking Control by means of existing means.
Adopt present embodiment,, can make holographic lens 41 miniaturizations owing to holographic lens 41 can be disposed near on the little position of the beam diameter of light source 3.
The 10th embodiment
The 10th embodiment, as shown in figure 11, being provided with around light source 3 has the protection of transparency window 15a box 15 on the light path.Transparency window 15a is provided with glass cover-plate 12.And the holographic lens 41 that setting has the concavees lens function on the inner surface of glass cover-plate 12.Holographic lens 42 with convex lens function also can be set or have concavees lens and the holographic lens of convex lens function 43 replacement holographic lenses 41.Adopt present embodiment, because holographic lens 41 is in the inside of protection box 15, the dust of protection box 15 outsides etc. can be attached on the holographic lens.Therefore, the light quantity of the light beam by holographic lens 41 can be owing to dust reduces.Holographic lens 41 also can be arranged on the outer surface of glass cover-plate 12.
Employing is arranged at the embodiment of the inside and outside any side of glass cover-plate 12 with holographic lens 41, can therefore, can seek the miniaturization of holographic lens at the configuration holographic lens 41 on the minimum position near the beam diameter of light source 3 more.
Even the optical-head apparatus 1 of above-mentioned the 8th～the 10th embodiment because CD 6 beam reflected do not see through holographic lens 41 (42,43), does not produce unnecessary diffraction.Therefore, in the light beam that light source 3 produces, the light quantity that arrives the light beam of photo detector 13 increases, thereby can improve the utilization ratio of light beam.
Can know from above-mentioned explanation and to recognize, adopt optical-head apparatus of the present invention, because this optical-head apparatus is provided with holographic lens on the optical element of necessity, the such optical element that only has hologram functional of holographic element plate needn't be set in addition, can reduce this a part of number of parts, reduce manufacturing expense.Because will being set, the surface configuration of the optical element of holographic lens makes plane or the surface relatively mild curved surface bigger again than the curvature towards light source one side of object lens, compare with the situation towards the surface of light source one side that is formed at object lens, the shape of holographic lens becomes simply, processing easily.For example, the metal die with optical element and the whole die casting shaping of holographic lens reaches high precision easily.Therefore can reduce the manufacturing expense of metal die, the manufacturing expense of optical-head apparatus also can reduce.Can improve the precision of the holographic lens of formation again.
Also have, when adjustment is provided with the position of optical element of holographic lens, the inherent function of this optical element is adjusted, also obtain adjusting with regard to the function that makes holographic lens.Therefore, unnecessary position to holographic lens is adjusted, and the assembly working of optical-head apparatus can be faster.
Because holographic lens is arranged on the optical element that disposes between beam splitter and the light source, the light beam of CD reflection does not see through holographic lens and injects photo detector again.Therefore, reflected beams is not subjected to the diffraction of holographic lens, and the light quantity that arrives the light beam of photo detector in the light beam that light source produces increases, thereby can improve the utilization factor of light beam.
Claims (15)
1. optical-head apparatus, it is characterized in that, possess: object lens, light source, surface configuration for than described object lens towards the optical element on the surperficial mild curved surface of light source one side or plane and be formed at this optical element surface, section is jagged a plurality of concentric circles grid, has the holographic lens of the function that makes the light beam focusing that sees through described object lens on the position different with the focal position of described object lens.
2. optical-head apparatus according to claim 1 is characterized in that, described optical element is a collimation lens.
3. optical-head apparatus according to claim 1 is characterized in that, described optical element is the optical instrument that makes the light path fork, and its side surface towards object lens is formed with described holographic lens.
4. optical-head apparatus according to claim 1 is characterized in that, described optical element is made of polarization beam splitter and 1/4 wavelength plate, forms described holographic lens on the surperficial or described polarization beam splitter of described 1/4 wavelength plate surface.
5. optical-head apparatus according to claim 1 is characterized in that, described optical element forms described holographic lens in reflection from the surface to upper reflector of the light beam of described light source.
6. optical-head apparatus according to claim 1 is characterized in that,
The structure of described each grid of holographic lens is, each outer peripheral face forms the periphery that is parallel to optical axis, and simultaneously, inner peripheral surface forms the precipitous more ring-type dip plane far away more, center of leaving holographic lens.
7. optical-head apparatus according to claim 1 is characterized in that,
The structure of each grid of described holographic lens is, each inner peripheral surface forms the periphery that is parallel to optical axis, outer circumference surface forms the precipitous more ring-type dip plane far away more, center of leaving holographic lens, and at the center of holographic lens, forms the conus portion that heave slightly the ring-type dip plane.
8. optical-head apparatus according to claim 1 is characterized in that, possesses the beam splitter that is equipped between described object lens and the described light source; Described holographic lens is arranged at, and comprises on the optical element that is provided in the described beam splitter between this beam splitter and the described light source.
9. optical-head apparatus according to claim 8 is characterized in that, described optical element is the beam splitter of cube shaped, and its surface towards light source one side is formed with described holographic lens.
10. optical-head apparatus according to claim 8 is characterized in that described optical element is a defraction grating device, and forms described holographic lens on the surface of a grilled opposite side of this grating.
11. optical-head apparatus according to claim 8 is characterized in that, described optical element is mounted in the protection transparent panel on the transparency window that is arranged at described light source protection box on every side, and its surface forms described holographic lens.
12. optical-head apparatus according to claim 11 is characterized in that, forms described holographic lens in described protection with the surface towards described protection box inboard of transparent panel.
13. optical-head apparatus according to claim 8 is characterized in that, described optical element is described holographic element plate, and its surface forms described holographic lens.
14. optical-head apparatus according to claim 8, it is characterized in that the structure of described each grid of holographic lens is that each outer peripheral face forms the periphery that is parallel to optical axis, simultaneously, inner peripheral surface forms the precipitous more ring-type dip plane far away more, center of leaving holographic lens.
15. optical-head apparatus according to claim 8, it is characterized in that, the structure of each grid of described holographic lens is, each inner peripheral surface forms the periphery that is parallel to optical axis, outer circumference surface forms the precipitous more ring-type dip plane far away more, center of leaving holographic lens, and, form the conus portion that heave slightly the ring-type dip plane at the center of holographic lens.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP268887/95 | 1995-10-17 | ||
| JP7268887A JPH09115173A (en) | 1995-10-17 | 1995-10-17 | Optical head device |
| JP268889/95 | 1995-10-17 | ||
| JP268889/1995 | 1995-10-17 | ||
| JP268887/1995 | 1995-10-17 | ||
| JP26888995A JP3399722B2 (en) | 1995-10-17 | 1995-10-17 | Optical head device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1157455A CN1157455A (en) | 1997-08-20 |
| CN1075221C true CN1075221C (en) | 2001-11-21 |
Family
ID=26548514
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN96122858A Expired - Fee Related CN1075221C (en) | 1995-10-17 | 1996-10-17 | Head device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1075221C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011096329A (en) * | 2009-10-30 | 2011-05-12 | Sanyo Electric Co Ltd | Optical pickup device |
| US11846779B2 (en) | 2018-03-15 | 2023-12-19 | Meta Platforms Technologies, Llc | Display device with varifocal optical assembly |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05303766A (en) * | 1992-04-27 | 1993-11-16 | Matsushita Electric Ind Co Ltd | Optical element for optical disk and optical head using the same |
| EP0587297A2 (en) * | 1992-08-07 | 1994-03-16 | Matsushita Electric Industrial Co., Ltd. | Image-information optical system, apparatus and method |
-
1996
- 1996-10-17 CN CN96122858A patent/CN1075221C/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05303766A (en) * | 1992-04-27 | 1993-11-16 | Matsushita Electric Ind Co Ltd | Optical element for optical disk and optical head using the same |
| EP0587297A2 (en) * | 1992-08-07 | 1994-03-16 | Matsushita Electric Industrial Co., Ltd. | Image-information optical system, apparatus and method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1157455A (en) | 1997-08-20 |
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