JPS58196633A - Double-beam optical head - Google Patents

Double-beam optical head

Info

Publication number
JPS58196633A
JPS58196633A JP57079377A JP7937782A JPS58196633A JP S58196633 A JPS58196633 A JP S58196633A JP 57079377 A JP57079377 A JP 57079377A JP 7937782 A JP7937782 A JP 7937782A JP S58196633 A JPS58196633 A JP S58196633A
Authority
JP
Japan
Prior art keywords
beams
recording
optical
reproducing
medium
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP57079377A
Other languages
Japanese (ja)
Other versions
JPH0512772B2 (en
Inventor
Masahiko Fujiwara
雅彦 藤原
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Nippon Electric Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NEC Corp, Nippon Electric Co Ltd filed Critical NEC Corp
Priority to JP57079377A priority Critical patent/JPS58196633A/en
Publication of JPS58196633A publication Critical patent/JPS58196633A/en
Publication of JPH0512772B2 publication Critical patent/JPH0512772B2/ja
Granted legal-status Critical Current

Links

Classifications

    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/12Heads, e.g. forming of the optical beam spot or modulation of the optical beam

Landscapes

  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Head (AREA)

Abstract

PURPOSE:To obtain recording and reproducing light spots in a comparatively easy way, by multiplexing the radiation beams of two diodes of different oscillating wavelengths so as to obtain the coincidence of optical axes with an approximately equal broadening angle and then leading the multiplexed beam to a convergent lens through a dispersing medium. CONSTITUTION:The beams 11a and 11b given from two semiconductor lasers 10a (recording) and 10b (reproducing) of different wavelengths are turned into parallel beams through collimator lenses 12 and 13 and then multiplexed so as to obtain the coincidence between the polarizing direction of the beam and the optical axis through an interference filter 14. The multiplexed beam 15 is turned into two beams 19a and 19b having slanting optical axes through a polarized beam splitter 16, a lambda/4 plate 17 and a prism 18 made of a material having high dispersing property. These two beams form two focusing spots 22a and 22b on a track 21a on a disk-shaped medium 21 through a convergent lens 1. In such a way, the recording and reproducing light spots 22a and 22b can be obtained in a comparatively easy way.

Description

【発明の詳細な説明】 イに等々して情@を記録し、同様に記録書n、た情・報
を再生する光学的情報記録、再生装置の光栄・\ラドに
関するものである。
DETAILED DESCRIPTION OF THE INVENTION This invention relates to an optical information recording and reproducing device that records information on A, etc. and similarly reproduces information on a record.

2トの淳読として記録さηた画像、音声等の情報を光学
的に再生する技術カS進み、ビデオ・ディスク、デ・′
クダル・オーディオ・ディスク等として実用化されてき
ている。また同様な技術を応用し単ζこ再生のみ774
’らず記録も行ない、メモリに利用する光ディスク・メ
モリ装置の開発も進んでいる。
Advances have been made in the technology for optically reproducing information such as images and sounds recorded as two-tone readings, and video discs, digital discs, etc.
It has been put into practical use as Kudal audio discs, etc. Also, by applying the same technology, only 774
Progress is also being made in the development of optical disk memory devices that can be used for memory purposes.

このような記録・再生が可能な光ディスク・メモリ装置
は従来の磁気ディスク装置等lこ比べ、装置が小型、軽
量、高記録密度、長期保存の信頼性が高い等の利点が有
り画像等のファイル・メモ+1 トして期待されている
。こり)ようft″光ディスク・メモリ装置では、最近
ではガス・レーザに比べ小型、・高効率の半導体レーザ
(La5er Diode L>l下LDお略記する)
を光源として用いる事が多く、通常LDと収束光畳糸、
情報信号及びサーボ信号の検出系、及び仲−車信号に応
じて光スポットをトうツク上に位置さぜるための微小変
位のビーム駆動手段を1つにi、L−ぬた光学・\ノド
をトラック追跡の際の粗動を行なう変位量の大きなアク
千ユエーダに乗せ情報トラ、りの選択追跡を行77jい
情報の記録、再生を行なっているっ従って、多くの機能
を併せ持つ光学ヘッドは記録媒体と共ζこ光デイスク装
置の性能を左右する重鰻な構成要素である。
Optical disk/memory devices capable of such recording and playback have the advantages of being smaller, lighter, higher recording density, and more reliable for long-term storage than conventional magnetic disk devices.・Memo+1 It is expected to be done. Recently, in optical disk memory devices, semiconductor lasers (La5er Diode L>L, abbreviated as LD), which are smaller and more efficient than gas lasers, are being used.
is often used as a light source, usually LD and convergent light tatami thread,
The information signal and servo signal detection system, and the minute displacement beam driving means for positioning the light spot on the track in response to the intermediate car signal are integrated into one. The throat is placed on a large-displacement actuator that performs coarse movements during track tracking, and the information tracker performs selective tracking and records and plays back information. Therefore, it is an optical head that has many functions. Along with the recording medium, this is an important component that influences the performance of the optical disk device.

従来の光学ヘッドでは構成の簡便な事から1つらねるよ
うな電気パルスfこよりLDを駆動し、再生時には記録
しへい値より充分低くかつSNRが確保出来るような光
出力レベルのCW動作でLDp用いている。しカ\しy
(がらこ0)ようなLL)の用′ハ方では I)記録直後の記録状態のモニタが不可能。
In conventional optical heads, the LD is driven by a single electric pulse f due to its simple configuration, and during playback, the LDp is used in CW operation at an optical output level that is sufficiently lower than the recording threshold and can ensure the SNR. There is. Shika\shiy
In the case of LL) such as LL) I) it is impossible to monitor the recording state immediately after recording.

2)記録時には大出力のパルス動作であるから検出系の
飽和の影響を除くため低光出力のレベルを設定し、更に
その時lこサンプル的にサーボ宿号を得るようにする必
要が有り検出系が難しいう という欠点が有る。そのため記録及び再生を行なつ光ス
ポットをそれぞれ別のLDのビームfこより@成し記録
ビームは単lこ記録のみ、再生ビームは情報信号の再生
及び記録、再生時り)サーボ信号検出ζご用いる制子ダ
ブル ビーム構成の光学・\ラドが望ましい。ダブル・
ビーム 光学ヘッドテGt 記録、°−再生用の光スポ
フトは収束レンズに対し光軸上でほぼ同じ位置に収束さ
れ、力1ら記録直後のモニタを行ζfうたぬ再生用スポ
ットは記録用スポットより回転するディスクのトラック
方向に数μm〜数10μm遅れた場所に形成される必要
がある。
2) During recording, a high-output pulse operation is used, so it is necessary to set a low optical output level to eliminate the effect of saturation of the detection system, and also to obtain the servo signal on a sample basis at that time. The disadvantage is that it is difficult to Therefore, the optical spots for recording and reproducing are formed from separate LD beams, and the recording beam is used only for single recording, and the reproducing beam is used for reproducing, recording, and reproducing information signals.) Servo signal detection is used. Optical/RAD with double beam configuration is preferable. double·
Beam Optical head TE Gt Recording, ° - The optical spot for reproduction is converged at almost the same position on the optical axis with respect to the converging lens, and the spot for reproduction is rotated from the spot for recording. It needs to be formed at a position delayed from several μm to several tens of μm in the track direction of the disk.

このようなダブル・ビーム・光学・・・ドを得るた  
   1めの1つの方法は光源であるLD>了レイ化す
る事であるが、現状では光学・\ラド収束光学系の拡大
倍率は1〜1/2程蜜であるためアレイの素子間の間隔
も数μm〜数10μm程度にする必要かあ(リ、素子間
の分離、動作の干渉、放熱等に問題が有り、了レイ中の
素子の特性のバラツキにも問題が有る。従って何らかの
光学系により2つのLDからのビームを合波する必要が
ある。この際先fこ述べ1こように記録用及び再生用ス
ポットは数μmから数10μm程度空間的に4+離され
ている必要が有るため、記録用及び再生用ビームは1つ
の共通の対物レンズに入射し、なおかつ2つのビームの
光軸は平行であってはならずある微小な角度だけ傾いて
いなけnばならない。第1図のように収束レンズ1の焦
点距離をfとし2つの平行なビームポット間の距離ΔX
は Δx = f tanθ=fθ と書ける。従って(=5■としてΔx=10μmを得よ
うとすnばθ= 2mrad (〜0.1 deg )
稈度ニする必要が有る。このような微小な角度だけ傾け
て2つのビームの光軸を調整する事は非常に困難であり
従来精変よぐ記録、再生用光スポットを形成する事は明
雅であった。本発明の目的はF述のようt(欠点を除き
比軸的容易に2つのLDから記録用、再生用の光スポッ
トが得られ、ろダブル・ビーム構成光学ヘッドを提供す
ることに有る。
In order to obtain such a double beam optical...
The first method is to make the light source LD > light, but at present the magnification of the optical/rad convergence optical system is about 1 to 1/2, so the spacing between the elements of the array is small. Is it necessary to make it several micrometers to several tens of micrometers? Therefore, it is necessary to combine the beams from the two LDs.In this case, as mentioned above, the recording and reproducing spots need to be spatially separated by about 4+ from several μm to several tens of μm. , the recording and reproducing beams are incident on one common objective lens, and the optical axes of the two beams must not be parallel but must be inclined by a certain small angle.As shown in Figure 1. Let the focal length of the converging lens 1 be f, and the distance between the two parallel beam pots ΔX
can be written as Δx=f tanθ=fθ. Therefore, if we try to obtain Δx=10μm with (=5■), then θ=2mrad (~0.1 deg)
It is necessary to check the culm. It is extremely difficult to adjust the optical axes of the two beams by tilting them at such a minute angle, and conventionally it has been elegant to form delicate optical spots for recording and reproducing. An object of the present invention is to provide an optical head having a double beam configuration, in which optical spots for recording and reproduction can be obtained from two LDs with relative ease, except for the drawbacks described in F.

本発明は発根波長の異なる2つのLDを用いそnぞれか
らの放射光をはげ拡カイリ角の等しい状態で完全に光軸
を一散するように合波し、合波した/ ビーム光洛中に波長により透過光の振れ角の異なる媒質
を配しその透過光を収束レンズに入射させで収束するも
のである。以下本発明につき図面を用いて詳細に説明す
る。
The present invention uses two LDs with different rooting wavelengths, and combines the emitted light from each in a state where the beam expansion angle is equal so that the optical axes are completely dispersed. A medium in which the deflection angle of transmitted light differs depending on the wavelength is placed in the field, and the transmitted light is made incident on a converging lens and converged. The present invention will be explained in detail below with reference to the drawings.

第2:図は本発明1こよるダブル・ビーム 光学・\ラ
ドの一実施例を示す図である。波長の異f(る2つの半
導体レーザー0a、10bからの放射光11a。
2nd: Figure is a diagram showing an embodiment of the double beam optics/rad according to the present invention. Emitted light 11a from two semiconductor lasers 0a and 10b with different wavelengths f.

11b(ばそnぞわ、jリメータ・レンズ12.13に
より平行化さn、平行状噸で干渉フィルター14により
合命される。ここでは半導体レーザー0aを記録光用、
1(lbを再生光用おしてそnぞn発揖波長0.83 
am 、 0.78 amのAlGaAs L Dを用
イタ。
11b, parallelized by the remeter lens 12.13, and aligned by the interference filter 14 in a parallel state.Here, the semiconductor laser 0a is used for recording light,
When using 1 (lb) for reproduction light, the emission wavelength is 0.83.
Ita using AlGaAs LD of 0.78 am and 0.78 am.

この波長はAlGaAs L Dでは典型的なものであ
り、しかも約Q、05μツの差が有るため通常の干渉フ
ィルターを用いて大きな損失無しで合波が可能である。
This wavelength is typical for AlGaAs LDs, and since there is a difference of about Q, 05μ, it is possible to combine the wavelengths without large losses using a normal interference filter.

ここで干渉フィルター14による合波は2つのビームの
偏光方向と光軸が一致するように行f、1′う。従って
調整自体は光軸間にある一定の角度を持たせる場合に比
し非常に容易であるっ合波さnたビーム15は通常σ)
光学へ・7ドと同様に偏光ビーム・スジ11ツタ16及
びλ/4W17から成るアイソレータ系を通り次に屈折
率分数の大きな材質から成るプリズム18を通りこの際
2つのビームの波長の違いから出射時の振れ角が異なり
互いに光軸が傾いた2つのビーム19a、19bとなる
Here, the multiplexing by the interference filter 14 is performed so that the polarization directions of the two beams and the optical axes coincide with each other. Therefore, the adjustment itself is much easier than when setting a certain angle between the optical axes.The combined beam 15 is usually σ)
To optics - Similar to the 7th mode, the polarized beam passes through an isolator system consisting of streaks 11, vines 16, and λ/4W 17, then passes through a prism 18 made of a material with a large refractive index fraction, and is emitted due to the difference in wavelength between the two beams. Two beams 19a and 19b are formed with different time deflection angles and optical axes tilted relative to each other.

先にも述べたように2つの波長の異なるビーム19a、
19bの光軸のなす角は0.1 deg程蜜でよいため
、プリズムIIIHこは通常の分光プリズム用ガラスを
用いることが出来る。また2つのビーム19a、19b
の為す角はプリズム18の分散だけでなく形状によって
も制御できるため極めて9髪よく設定出来る。この2つ
のビーム19a、19bは光学・\ラドを薄型とするた
めに設けらn、たミラー20により反射され収束レンズ
1cこよりディス〃状媒体21のトラック21aの上に
2つの収束スポット22a、22bmv或される。この
時トラック21aの方向と2つの収束スポットの方向を
一致させ媒体21の回転に対し記録用LD10aにより
e成されろスポット22aを再生用LD10bにより形
成さnるスボッl−22bより前に配置する。2つのビ
ーム19a、19b(ま媒体により反射さn再び光路を
逆行するが往路とは偏光方向が直交しているため偏光ビ
ーム スプリッタ16により反射光23としてとり出さ
れる。この反射光23のうち再生用LD10bの発振波
長の成分23bだけを干渉フィルタ24により覗り出し
、情@信号及びフォーカス、トラック方向のサーボ信号
検出系251こより情報及びサーボ信号の検出を行なう
。このような構成により、ば光スポット122aによる
配録の状轢を光スボ、 ト22bにより記録直後にモニ
タが可能となりし力\も、再生用LD10bは低出力の
CW動作で用いわば良いためサーボ信号の検出も良好t
こ行なえることになる。し艮 かも2つのLDloa、10b力)らのく−ムを一勢光
軸が一致するように合波し、その後にプリズム18によ
り光軸間の角度を調整するため非常に調整が容易である
。本実施例では2つのビームの合波に干渉フィルタを用
いたがLDの出力に余裕が有する場合に(オ激なるハー
フ・ミラーでもかまわない。また波長により透過光の振
れ角が異なる媒質上してここで(″i分散の大きな材料
によるプリズムを用いたがこnもグレーティング等でお
きかえることが可能である。また本実施例では記録用L
Dと発振波長λ=O,S3μm1再生用LDとして発振
波長0.78 am (D GaAlAs L Dを用
いたが、発振波長はこれ【こ限られないことは言う迄も
なく、現在開発の進んでいる更に短波長のLDも用いろ
事が出来る。
As mentioned earlier, the beams 19a with two different wavelengths,
Since the angle formed by the optical axis of 19b may be as small as 0.1 degree, ordinary glass for spectroscopic prisms can be used for prism IIIH. Also two beams 19a, 19b
The angle formed by the prism can be controlled not only by the dispersion of the prism 18 but also by its shape, so it can be set extremely precisely. These two beams 19a and 19b are reflected by a mirror 20 provided in order to make the optical system thin, and from the converging lens 1c, two convergent spots 22a and 22bmv are formed on the track 21a of the disk-shaped medium 21. be done. At this time, the direction of the track 21a and the direction of the two convergence spots are made to match, and the spot 22a formed by the recording LD 10a is placed in front of the spot 22b formed by the reproduction LD 10b as the medium 21 rotates. . The two beams 19a and 19b (reflected by the medium) travel back along the optical path again, but since their polarization directions are perpendicular to the outgoing path, they are extracted as reflected light 23 by the polarizing beam splitter 16. Only the component 23b of the oscillation wavelength of the LD 10b is detected by the interference filter 24, and the information and servo signals are detected by the servo signal detection system 251 in the information and focus and track directions. The state of the recording by the spot 122a can be monitored immediately after recording by the optical sensor 22b, and since the playback LD 10b can be used in low-output CW operation, the detection of servo signals is also good.
You can do this. However, the two beams (LDloa, 10b) are combined so that their optical axes coincide, and then the angle between the optical axes is adjusted using the prism 18, so adjustment is very easy. . In this example, an interference filter was used to combine the two beams, but if there is a margin in the output of the LD (a very strong half mirror may also be used. (Although a prism made of a material with large dispersion is used here, it is also possible to replace it with a grating, etc. In this example, the recording L
D and oscillation wavelength λ = O, S 3 μm 1 The oscillation wavelength is 0.78 am (D GaAlAs LD was used, but the oscillation wavelength is this [it goes without saying that this is not limited, and the development is currently progressing). It is also possible to use an LD with a shorter wavelength.

以上、詳細に説明したように本発明によれば記録、再生
をそnぞれ独立なビームで行なう事により記録直後の記
録状態のモニタが可能で、専定なフォーカス・トラック
方向等のサーボi%が得らnl、しη)も理#が容易f
(、/1ゴル ビーム・光学I\ウッド実現出来ろ。
As explained above in detail, according to the present invention, recording and reproduction are performed using independent beams, which makes it possible to monitor the recording state immediately after recording, and to control the servo i for specific focus and track directions. % is obtained, and η) is also easy to reason f
(,/1 Gol Beam/Optical I\Wood can be realized.

【図面の簡単な説明】[Brief explanation of drawings]

第1図は記録再生用の光スポットの分離を説明するため
の図、真2図(1不発明にfる′!フル・ビ、−ム・光
栄へ、ドの一実施例を示す図である。 図tこ於て1は収束レンズ゛、10a、10bfま半導
体1/−セ、lla、Ilb、15,19a、19b、
23゜?3b’すレーザ光、12.13’すメリメータ
・レンズ、14.24は干渉フィルタ、16は偏光ビー
ム・スプリッタ、17はλ/4板、18(ゴブリズム、
20は反射鏡、21は記録媒体、21aはトラック、2
2 a + 22 bIt tスポット、25!jm号
検出系である。
Figure 1 is a diagram for explaining the separation of optical spots for recording and reproduction, and Figure 2 is a diagram showing an embodiment of the present invention. In Fig. t, 1 is a converging lens, 10a, 10bf, semiconductor 1/-, lla, Ilb, 15, 19a, 19b,
23°? 3b' laser beam, 12.13' smelometer lens, 14.24 interference filter, 16 polarizing beam splitter, 17 λ/4 plate, 18 (gobulism,
20 is a reflecting mirror, 21 is a recording medium, 21a is a track, 2
2 a + 22 bIt t spot, 25! This is the JM detection system.

Claims (1)

【特許請求の範囲】[Claims] 互いに異なる発振波長を有する2つの半導体レーザと、
前記2つの半導体レーザ力)らの故射光をその拡がり角
が等しい状態でヤイ光軸を一致させτ合波する光学的手
段と、合波された光の光路中に挿入した、波長により出
射光の振r、角の異なる媒質と、前記波長により出射光
の撮れ角の異なる媒質により姶チ光軸が微少角だけ傾く
ように杉成さnたそれぞれ独立の波長成分を持つ2つの
ビームが略垂直入射となるように設置した収束レンズと
この収束レンズハ)ら出て記録媒体を照射して反射され
た光から少くも1つの波長の光を分離する光学的手段と
を具備する事を特徴とする夕°プル・ビーム・光栄ヘッ
ドっ
two semiconductor lasers having different oscillation wavelengths;
an optical means for aligning the optical axes of the incident light from the two semiconductor lasers with equal divergence angles and τ multiplexing; Two beams each having independent wavelength components are formed so that the optical axis is tilted by a small angle by a medium with different angles and angles, and a medium with a different angle of view of the emitted light depending on the wavelength. The recording medium is characterized by comprising: a converging lens installed so that the incidence is perpendicular; and an optical means for separating at least one wavelength of light from the light emitted from the converging lens and reflected by the recording medium. Sunset, pull beam, honor head
JP57079377A 1982-05-12 1982-05-12 Double-beam optical head Granted JPS58196633A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP57079377A JPS58196633A (en) 1982-05-12 1982-05-12 Double-beam optical head

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP57079377A JPS58196633A (en) 1982-05-12 1982-05-12 Double-beam optical head

Publications (2)

Publication Number Publication Date
JPS58196633A true JPS58196633A (en) 1983-11-16
JPH0512772B2 JPH0512772B2 (en) 1993-02-18

Family

ID=13688175

Family Applications (1)

Application Number Title Priority Date Filing Date
JP57079377A Granted JPS58196633A (en) 1982-05-12 1982-05-12 Double-beam optical head

Country Status (1)

Country Link
JP (1) JPS58196633A (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0159785A2 (en) * 1984-03-07 1985-10-30 Kabushiki Kaisha Toshiba Optical recording & reproducing apparatus
US4980061A (en) * 1985-10-16 1990-12-25 E. I. Du Pont De Nemours And Company Coating process for composite reverse osmosis membranes
JPH06111329A (en) * 1992-08-24 1994-04-22 Internatl Business Mach Corp <Ibm> Laser electric power control system for optical device
US11684155B2 (en) 2017-01-27 2023-06-27 143046 Canada Inc. Pivotable overhead storage unit
US11723457B2 (en) 2017-01-27 2023-08-15 143046 Canada Inc. Overhead storage unit
US11864648B2 (en) 2019-10-04 2024-01-09 143046 Canada Inc. Overhead storage unit with pivoting storage containers

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5580832A (en) * 1978-12-15 1980-06-18 Oki Electric Ind Co Ltd Wavelength multiple record/reproduction system
JPS56134774U (en) * 1980-03-11 1981-10-13
JPS56163531A (en) * 1980-05-16 1981-12-16 Nippon Telegr & Teleph Corp <Ntt> Optical information recorder and reproducer

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5580832A (en) * 1978-12-15 1980-06-18 Oki Electric Ind Co Ltd Wavelength multiple record/reproduction system
JPS56134774U (en) * 1980-03-11 1981-10-13
JPS56163531A (en) * 1980-05-16 1981-12-16 Nippon Telegr & Teleph Corp <Ntt> Optical information recorder and reproducer

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0159785A2 (en) * 1984-03-07 1985-10-30 Kabushiki Kaisha Toshiba Optical recording & reproducing apparatus
US4980061A (en) * 1985-10-16 1990-12-25 E. I. Du Pont De Nemours And Company Coating process for composite reverse osmosis membranes
JPH06111329A (en) * 1992-08-24 1994-04-22 Internatl Business Mach Corp <Ibm> Laser electric power control system for optical device
US11684155B2 (en) 2017-01-27 2023-06-27 143046 Canada Inc. Pivotable overhead storage unit
US11723457B2 (en) 2017-01-27 2023-08-15 143046 Canada Inc. Overhead storage unit
US11864648B2 (en) 2019-10-04 2024-01-09 143046 Canada Inc. Overhead storage unit with pivoting storage containers

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