JP2015154882A

JP2015154882A - Ophthalmologic diagnostic apparatus equipped with led illumination

Info

Publication number: JP2015154882A
Application number: JP2014031406A
Authority: JP
Inventors: 佑介井澤; Yusuke Izawa; 達哉金原; Tatsuya Kanehara
Original assignee: Kowa Co Ltd
Current assignee: Kowa Co Ltd
Priority date: 2014-02-21
Filing date: 2014-02-21
Publication date: 2015-08-27
Anticipated expiration: 2034-02-21
Also published as: JP6277011B2

Abstract

PROBLEM TO BE SOLVED: To provide an ophthalmologic diagnostic apparatus in which a flicker does not occur in an LED even when a battery is exhausted.

SOLUTION: In an ophthalmologic diagnostic apparatus which includes an LED drive part 20 for driving an LED 11, and a light control part 15 for modulating a direct-current power source voltage VB from a battery 12 into a pulse voltage VP of a predetermined wavelength T composed of a high voltage part VH and a low voltage part VL, and outputting it to the LED drive part 20, and in which the LED drive part 20 drives the LED 11 by the pulse voltage VP output from the light control part 15, an output monitoring part 16 for monitoring whether or not a voltage value of the low voltage part of the power source voltage VB that fluctuates by an influence of driving the LED 11 by the pulse voltage is not lower than a threshold voltage set to a value exceeding the minimum driving voltage value stops supplying the power source voltage VB in order to stop driving the LED 11 when it determines that the voltage value of the low voltage part of the power source voltage is lower than the threshold voltage.

Description

本発明は、被検眼を照明する光源としてＬＥＤを光源として備えた眼科診断装置に関わり、特に、ＬＥＤを、電池駆動によるパルス幅変調（ＰＷＭ）方式によりその明るさを調節する方式の眼科診断装置に関する。 The present invention relates to an ophthalmologic diagnosis apparatus having an LED as a light source for illuminating a subject's eye, and in particular, an ophthalmologic diagnosis apparatus that adjusts the brightness of a LED by a battery-driven pulse width modulation (PWM) method. About.

被検眼の所定位置にスリット光などの観察光を照射して、被検眼の例えば前眼部の状態を観察する手持ち式の眼科診断装置が知られている。この種の眼科診断装置としては、例えば、特許文献１に示すものが知られている。 2. Description of the Related Art A hand-held ophthalmic diagnostic apparatus is known that irradiates observation light such as slit light to a predetermined position of an eye to be examined to observe the state of, for example, an anterior eye portion of the eye to be examined. As this type of ophthalmologic diagnosis apparatus, for example, the one shown in Patent Document 1 is known.

最近、観察光の光源として、コストや安定性、寿命の問題などから、ＬＥＤが使用されるようになってきている。この場合、当然光量（明るさ）を調節したいという要望があるが、光量の調整方法の一つとして、ＬＥＤを高い電圧（Ｈ）と低い電圧（Ｌ）からなるパルス状の電圧をかけて駆動し、高い電圧（Ｈ）と低い電圧（Ｌ）との印加時間の割合（デューティ比）を調整することで、その明るさを調節するパルス幅変調方式（一般的にはＰＷＭ方式と呼ばれる）が知られている。この方法によれば、ＬＥＤから照射される光の色合いが変化しないことから、眼科診断装置などの医療機器の診断部を照らすための光源など、色合いに非常に重点が置かれる分野では、積極的に採用されつつあり、前述の眼科診断装置においても同様である。 Recently, LEDs have been used as a light source for observation light because of problems such as cost, stability, and lifetime. In this case, there is a desire to adjust the light quantity (brightness), but as one of the light quantity adjustment methods, the LED is driven by applying a pulsed voltage composed of a high voltage (H) and a low voltage (L). Then, there is a pulse width modulation method (generally called PWM method) that adjusts the brightness by adjusting the ratio (duty ratio) of application time between the high voltage (H) and the low voltage (L). Are known. According to this method, since the hue of light emitted from the LED does not change, it is positive in a field where the hue is very emphasized, such as a light source for illuminating a diagnostic unit of a medical device such as an ophthalmologic diagnosis apparatus. The same applies to the aforementioned ophthalmologic diagnosis apparatus.

特開２００４−１６７０２８号Japanese Patent Application Laid-Open No. 2004-167028

このＰＷＭ制御方法によって制御されるＬＥＤを光源として用いた装置、例えば手持ち式、携帯型のような電池駆動の装置（特許文献１に示された手持ち式スリットランプなど）の場合、ある一つの問題が生じる。即ち、ＬＥＤには、その発光駆動に必要な最低駆動電圧値（順方向電圧：Ｖｆ）があり、電池から供給される電圧が、電池の消耗などによって当該最低駆動電圧値を下回るとその発光動作が停止してしまうこととなる。これは一般的なＬＥＤの性質で、ＬＥＤのＰＮ接合部での電子-ホール再結合に必要なエネルギーが十分でないと、ＬＥＤが発光しないということによるものである。この最低駆動電圧値は、主にＬＥＤ自体の発光色に依存するが、例えば青色の場合、２．８〜３．０Ｖ程度のものが知られている。 In the case of a device using an LED controlled by this PWM control method as a light source, such as a hand-held or portable battery-powered device (such as the hand-held slit lamp shown in Patent Document 1), there is one problem. Occurs. That is, the LED has a minimum driving voltage value (forward voltage: Vf) necessary for driving its light emission, and when the voltage supplied from the battery falls below the minimum driving voltage value due to battery exhaustion or the like, the light emitting operation is performed. Will stop. This is a general LED property, because the LED does not emit light unless the energy required for electron-hole recombination at the PN junction of the LED is sufficient. This minimum drive voltage value mainly depends on the light emission color of the LED itself, but for example, about 2.8 to 3.0 V is known in the case of blue.

このＬＥＤに対してＰＷＭ方式による制御を使用すると、ＬＥＤが駆動される（電流がＬＥＤを流れる）影響で電源側の電圧（電源電圧）も、高い電圧（Ｈ）と低い電圧（Ｌ）との間で、ＰＭＷによる駆動電圧とは逆位相のパルス状の電圧変動が生じる。この際、電池が消耗状態になっていると、ＬＥＤがＰＭＷの高い電圧（Ｈ）で点灯されると、逆位相の電源電圧が低い電圧（Ｌ）となり、最低駆動電圧値を下回ってしまい、ＬＥＤが消灯する場合が生じる。ＬＥＤが消灯すると、ＬＥＤを流れる電流が無くなるので、電源側の電圧は高い電圧（Ｈ）に戻り、最低駆動電圧値を上回って、ＬＥＤが再度点灯することとなり、これが繰り返される結果フリッカーが生じて、被検眼に対する悪影響の発生及び想定したＰＭＷ方式による駆動とは異なるサイクルでＬＥＤが駆動されてしまう懸念が生じる。 When the control by the PWM method is used for this LED, the voltage on the power supply side (power supply voltage) is also a high voltage (H) and a low voltage (L) due to the influence of the LED being driven (current flows through the LED). In the meantime, a pulse-like voltage fluctuation having a phase opposite to that of the drive voltage by the PMW occurs. At this time, if the battery is depleted, when the LED is lit at a high PMW voltage (H), the power supply voltage in the opposite phase becomes a low voltage (L), which is below the minimum drive voltage value, There is a case where the LED is turned off. When the LED is turned off, the current flowing through the LED disappears, so the voltage on the power supply side returns to a high voltage (H), exceeds the minimum drive voltage value, and the LED is turned on again. As a result, flicker occurs. There is a concern that the adverse effect on the eye to be examined occurs and the LED is driven in a different cycle from the driving by the assumed PMW method.

また、ＰＭＷ方式でＬＥＤを駆動する場合、電源投入時点から、ＰＭＷ用の駆動パルスが生成されるまでの間、パルス変調されていない電池からの直流電圧（電源電圧）が直接ＬＥＤに印加され、ＬＥＤが瞬間的に大光量で発光駆動されてしまい、被検眼に対して悪影響を与える危険性がある。 In addition, when driving an LED by the PMW method, a DC voltage (power supply voltage) from a battery that is not pulse-modulated is directly applied to the LED from the time of power-on until a drive pulse for PMW is generated, There is a risk that the LED is instantaneously driven to emit light with a large amount of light, which adversely affects the eye to be examined.

こうした点を改善するために、電源投入時に、パルス変調前の直流電圧（電源電圧）がＬＥＤに入力しないように、一定の遅延時間（例えば、５０ｍｓｅｃ程度）だけＬＥＤへの駆動電圧の印加を遅らせる遅延回路を設け、ＰＭＷ用の駆動パルスが生成された後に当該駆動パルスでＬＥＤを駆動する方式が提案されている。 In order to improve these points, the application of the drive voltage to the LED is delayed by a certain delay time (for example, about 50 msec) so that the DC voltage (power supply voltage) before pulse modulation is not input to the LED when the power is turned on. There has been proposed a system in which a delay circuit is provided and an LED is driven with the drive pulse after a drive pulse for PMW is generated.

しかし、この方法を用いると、前述の電池の消耗に伴うフリッカー時において、電源側の電圧（電源電圧）が低い電圧（Ｌ）となった時に、ＬＥＤの駆動が一旦停止することとなる。そして、ＬＥＤの駆動が無くなると、電源側の電圧が高い電圧（Ｈ）に戻るので、当該高い電圧（Ｈ）が遅延回路に入力し、遅延回路が、電源が投入されたものと誤判定して、ＬＥＤの駆動を所定時間遅延させるように制御することから、ＬＥＤの消灯時間が長くなり、フリッカーがより顕著に生じてしまう不都合が生じる可能性がある。 However, when this method is used, the driving of the LED is temporarily stopped when the voltage on the power supply side (power supply voltage) becomes a low voltage (L) at the time of flicker accompanying the above-described battery consumption. When the LED is not driven, the voltage on the power supply side returns to a high voltage (H), so that the high voltage (H) is input to the delay circuit, and the delay circuit erroneously determines that the power is turned on. Thus, since the LED drive is controlled to be delayed for a predetermined time, there is a possibility that the LED turn-off time becomes longer and inconvenience that the flicker is more noticeably generated.

そこで、本発明は、電池が消耗してもＬＥＤにフリッカーが生じることの無い眼科診断装置を提供することを第１の目的とし、更に、電源投入時の遅延回路を装備しても、電池の消耗時に悪影響を与えることのない眼科診断装置を提供することを第２の目的とするものである。 Accordingly, the first object of the present invention is to provide an ophthalmic diagnostic apparatus in which flickering does not occur in an LED even when the battery is exhausted. Furthermore, even if a delay circuit at power-on is provided, It is a second object of the present invention to provide an ophthalmologic diagnosis apparatus that does not adversely affect the consumption.

本発明の第１の観点は、最低駆動電圧値（Ｖｆ）が設定されたＬＥＤ（１１）、該ＬＥＤ（１１）を発光駆動するＬＥＤ駆動部（２０）、電池（１２）及び、該電池（１２）からの直流の電源電圧（ＶＢ）を高電圧部（ＶＨ）及び低電圧部（ＶＬ）からなる所定波長（Ｔ）のパルス電圧（ＶＰ）に変調して前記ＬＥＤ駆動部（２０）に出力する電圧変調手段（１５）を有し、前記ＬＥＤ駆動部（２０）は前記電圧変調手段（１５）から出力されたパルス電圧（ＶＰ）で前記ＬＥＤ（１１）を駆動する眼科診断装置（１）において、
前記パルス電圧（ＶＰ）による駆動される前記ＬＥＤ（１１）の駆動の影響により変動する前記電源電圧（ＶＢ）の低電圧部（ＶＢＬ）の電圧値が前記最低駆動電圧値（Ｖｆ）を超える値に設定された閾値電圧（ＴＨＶ）を下回っていないかを監視する電圧監視手段（１６）及び、
前記電圧監視手段（１６）が、前記低電圧部（ＶＢＬ）の電圧値が前記閾値電圧（ＴＨＶ）を下回ったものと判定した場合に、前記電源電圧（ＶＢ２）の供給を停止して前記ＬＥＤ（１１）の駆動を停止する電圧供給停止手段（１６）を有することを特徴とするものである。 According to a first aspect of the present invention, an LED (11) in which a minimum drive voltage value (Vf) is set, an LED drive unit (20) for driving the LED (11) to emit light, a battery (12), and the battery ( 12) The direct current power supply voltage (VB) from 12) is modulated into a pulse voltage (VP) having a predetermined wavelength (T) composed of a high voltage portion (VH) and a low voltage portion (VL), and then applied to the LED drive portion (20). The ophthalmic diagnostic apparatus (1) has voltage modulating means (15) for outputting, and the LED driving section (20) drives the LED (11) with the pulse voltage (VP) outputted from the voltage modulating means (15). )
A voltage value of the low voltage portion (VBL) of the power supply voltage (VB) that fluctuates due to the influence of driving of the LED (11) driven by the pulse voltage (VP) exceeds the minimum driving voltage value (Vf). Voltage monitoring means (16) for monitoring whether or not the threshold voltage (THV) set to
When the voltage monitoring means (16) determines that the voltage value of the low voltage part (VBL) is lower than the threshold voltage (THV), the supply of the power supply voltage (VB2) is stopped and the LED A voltage supply stop means (16) for stopping the driving of (11) is provided.

本発明の第２の観点は、前記電池（１２）からの電源投入時に、前記ＬＥＤ駆動部（２０）による前記ＬＥＤ（１１）の駆動を前記電源投入時から所定時間禁止する遅延制御手段（１９）を有することを特徴として構成される。 According to a second aspect of the present invention, when the power from the battery (12) is turned on, the delay control means (19) prohibits the LED (11) from being driven by the LED drive unit (20) for a predetermined time after the power is turned on. ).

本発明の第３の観点は、前記電圧変調手段（１５）から出力されるパルス電圧（ＶＰ）の前記波長（Ｔ）を変更することが出来る波長変更手段（１５）を有することを特徴として構成される。 A third aspect of the present invention is characterized by comprising wavelength changing means (15) capable of changing the wavelength (T) of the pulse voltage (VP) output from the voltage modulating means (15). Is done.

本発明の第４の観点は、前記眼科診断装置（１）は、被検眼の画像を動画で記録することが出来るカメラ（７）を着脱自在に有していることを特徴として構成される。 The fourth aspect of the present invention is characterized in that the ophthalmic diagnosis apparatus (1) has a detachable camera (7) capable of recording an image of the eye to be examined as a moving image.

本発明の第１の観点によれば、ＬＥＤ駆動の影響を受けた電源電圧（ＶＢ）の低電圧部（ＶＢＬ）の電圧値が閾値電圧（ＴＨＶ）を下回った場合に、電圧供給停止手段（１６）によりＬＥＤ（１１）の駆動が停止されるので、電源電圧（ＶＢ）の低電圧部（ＶＢＬ）の電圧値が最低駆動電圧値（Ｖｆ）を下回って、ＬＥＤ（１１）がフリッカーを生じる前に、ＬＥＤ（１１）の駆動を停止することが出来、電池（１２）が消耗してもＬＥＤ（１１）にフリッカーが生じることの無い眼科診断装置を提供することが可能となる。 According to the first aspect of the present invention, when the voltage value of the low voltage portion (VBL) of the power supply voltage (VB) affected by the LED driving is lower than the threshold voltage (THV), the voltage supply stopping means ( 16), the driving of the LED (11) is stopped, so that the voltage value of the low voltage portion (VBL) of the power supply voltage (VB) falls below the minimum driving voltage value (Vf), and the LED (11) causes flicker. Before, it becomes possible to provide an ophthalmic diagnostic apparatus that can stop driving the LED (11) and that does not cause flickering in the LED (11) even when the battery (12) is exhausted.

本発明の第２の観点によれば、遅延制御手段（１９）により、電源投入時のパルス変調前の直流の電源電圧（ＶＢ）がＬＥＤ（１１）に入力しないように、所定時間だけＬＥＤ（１１）への駆動電圧の印加を遅らせる制御をする場合でも、電源電圧（ＶＢ２）が最低駆動電圧値（Ｖｆ）を下回ってＬＥＤ（１１）が消灯する前に、ＬＥＤ（１１）の駆動が完全に停止されるので、遅延制御手段（１９）の誤動作を未然に防止することが出来、遅延制御手段（１９）の存在が電池の消耗時に悪影響を与える危険性を排除することが出来る。 According to the second aspect of the present invention, the delay control means (19) allows the LED (11) for a predetermined time so that the DC power supply voltage (VB) before pulse modulation at the time of power-on is not input to the LED (11). 11) Even when the control for delaying the application of the drive voltage to 11) is performed, the LED (11) is completely driven before the power supply voltage (VB2) falls below the minimum drive voltage value (Vf) and the LED (11) is turned off. Therefore, the malfunction of the delay control means (19) can be prevented in advance, and the risk that the presence of the delay control means (19) will adversely affect battery consumption can be eliminated.

本発明の第３の観点によれば、波長変更手段（１５）により、パルス電圧（ＶＰ）の前記波長（Ｔ）を変更することが出来るので、カメラなどで動画を取得する際に、カメラのシャッタースピードに応じて、波長を調整することが出来、画像に干渉縞が生じることを未然に防止することが出来る。 According to the third aspect of the present invention, the wavelength (T) of the pulse voltage (VP) can be changed by the wavelength changing means (15). The wavelength can be adjusted according to the shutter speed, and interference fringes can be prevented from occurring in the image.

本発明の第４の観点によれば、カメラ（７）により、干渉縞のない画像を容易に取得することが出来る。 According to the 4th viewpoint of this invention, an image without an interference fringe can be easily acquired with a camera (7).

なお、括弧内の番号等は、図面における対応する要素を示す便宜的なものであり、従って、本記述は図面上の記載に限定拘束されるものではない。 Note that the numbers in parentheses are for the sake of convenience indicating the corresponding elements in the drawings, and therefore the present description is not limited to the descriptions on the drawings.

図１は、本発明が適用される眼科診断装置の一例を示す外観図。FIG. 1 is an external view showing an example of an ophthalmologic diagnosis apparatus to which the present invention is applied. 図２は、図１の眼科診断装置のＬＥＤ駆動系の一例を示す制御ブロック図。FIG. 2 is a control block diagram illustrating an example of an LED drive system of the ophthalmologic diagnosis apparatus of FIG. 図３は、ＬＥＤのＰＷＭ方式による駆動電圧波形及びその際の電源電圧の一例を示す図。FIG. 3 is a diagram illustrating an example of a driving voltage waveform of an LED by a PWM method and a power supply voltage at that time.

以下、図面に基づき、本発明の実施例を説明する。 Embodiments of the present invention will be described below with reference to the drawings.

手持ち式の眼科診断装置１は、図１に示すように、筐体１ａを有しており、筐体１ａは、板状のベース２を有している。ベース２の図中右端部には、同様に筐体１ａを構成する柱状に形成されたグリップバー３が設けられている。グリップバー３の図中左側面には、後述する電源部１３に接続されたＬＥＤスイッチ３ａが水平方向である矢印Ａ、Ｂ方向に押下自在に設けられており、また、グリップバー３の図中右側面には、明るさ調整用ダイアル３ｂが図中水平方向である矢印Ｈ、Ｉ方向に回転操作自在に設けられている。 As shown in FIG. 1, the hand-held ophthalmologic diagnosis apparatus 1 has a housing 1 a, and the housing 1 a has a plate-like base 2. At the right end of the base 2 in the figure, a grip bar 3 formed in the shape of a column that similarly forms the housing 1a is provided. On the left side of the grip bar 3 in the figure, an LED switch 3a connected to a power supply unit 13 to be described later is provided so as to be freely pressed in the directions of arrows A and B which are horizontal directions. On the right side, a brightness adjustment dial 3b is provided so as to be rotatable in directions indicated by arrows H and I which are horizontal in the drawing.

グリップバー３の図中上方には、検眼部５が設けられており、検眼部５には、接眼レンズ５ａ、プリズム５ｂ及び対物レンズ５ｃなどからなる光路系６が設けられている。なお、図示した光路系６は、説明の便宜上、模式的に示した概略図で有り、実際の光路系６を示すものではない。実際の眼科診断装置１の光路系６は、診断装置に要求される性能を発揮する上で必要な様々な部品が付加され、光路もより複雑に構成されていることが多いが、本発明の要旨とは離れるので、ここでは、その説明及び図示は省略する。従って、光路系６は必要に応じて任意の構成を取ることが出来る。 An optometry unit 5 is provided above the grip bar 3 in the drawing, and the optometry unit 5 is provided with an optical path system 6 including an eyepiece 5a, a prism 5b, an objective lens 5c, and the like. The illustrated optical path system 6 is a schematic diagram schematically shown for convenience of explanation, and does not show the actual optical path system 6. The optical path system 6 of the actual ophthalmologic diagnosis apparatus 1 is provided with various parts necessary for exhibiting the performance required for the diagnosis apparatus, and the optical path is often configured more complicatedly. Since it is different from the gist, the description and illustration are omitted here. Therefore, the optical path system 6 can take any configuration as required.

検眼部５の図中上部には、カメラ７が着脱自在に配置されており、カメラ７は、検眼部５で検査者９が光路系６を介して補足することの出来る被検眼の画像を、動画又は静止画の形で記録することが出来るように構成されている。 A camera 7 is detachably disposed in the upper part of the optometry unit 5 in the figure, and the camera 7 is an image of the eye to be examined that can be captured by the examiner 9 via the optical path system 6 in the optometry unit 5. Can be recorded in the form of a moving image or a still image.

また、ベース２の図１左方には、回転アーム２ａが軸２ｂを介して図中水平方向である矢印Ｃ，Ｄ方向に回転自在に設けられており、回転アーム２ａには、円筒状に形成された、被検眼に観察光であるスリット光を照射するためのＬＥＤ照明部１０が設けられている。ＬＥＤ照明部１０の先端部には、照射部１０ａが設けられており、照射部１０ａはＬＥＤ照明部１０の内部に設けられたＬＥＤ（図２参照）１１から発せられる光８を矢印Ｅ方向にスリット状の観察光として照射することが出来る。なお、ＬＥＤ１１は、例えば２．８Ｖの最低駆動電圧値Ｖｆが仕様として設定されており、ＬＥＤ１１に供給される駆動電圧がこの最低駆動電圧値Ｖｆを下回ると、ＬＥＤ１１は駆動されることはない。 Further, on the left side of the base 2 in FIG. 1, a rotating arm 2a is provided so as to be rotatable in the directions of arrows C and D, which are horizontal in the figure, via a shaft 2b. The rotating arm 2a is formed in a cylindrical shape. An LED illumination unit 10 for irradiating the formed eye to be examined with slit light as observation light is provided. The irradiation part 10a is provided in the front-end | tip part of the LED illumination part 10, and the irradiation part 10a emits the light 8 emitted from LED (refer FIG. 2) 11 provided in the inside of the LED illumination part 10 in the arrow E direction. Irradiation can be performed as slit-shaped observation light. Note that the LED 11 has a minimum drive voltage value Vf of, for example, 2.8 V set as a specification. If the drive voltage supplied to the LED 11 falls below the minimum drive voltage value Vf, the LED 11 is not driven.

また、眼科診断装置１は、図２に示すように、筐体１ａやＬＥＤ照明部１０など適宜な部分に収納された装置駆動部１４を有しており、装置駆動部１４は、乾電池などからなる電池１２を有している。電池１２には、電源部１３が接続している。電源部１３には、出力監視部１６及び電圧変調手段を構成する調光部１５が接続されており、調光部１５には、明るさ調整用ダイアル３ｂ及び波長変更ダイアル１５ａが操作自在に接続している。また、出力監視部１６にはアラーム部１７が接続しており、調光部１５にはＬＥＤ駆動２０が接続している。ＬＥＤ駆動部２０には、ＬＥＤ１１及び遅延制御部１９が接続している。 Further, as shown in FIG. 2, the ophthalmologic diagnosis apparatus 1 has a device drive unit 14 housed in an appropriate part such as the housing 1a and the LED illumination unit 10, and the device drive unit 14 is made of a dry battery or the like. A battery 12 is provided. A power supply unit 13 is connected to the battery 12. The power supply unit 13 is connected to an output monitoring unit 16 and a dimming unit 15 constituting voltage modulation means, and the dimming unit 15 is operably connected to a dial 3b for brightness adjustment and a wavelength changing dial 15a. doing. An alarm unit 17 is connected to the output monitoring unit 16, and an LED drive 20 is connected to the dimming unit 15. An LED 11 and a delay control unit 19 are connected to the LED drive unit 20.

眼科診断装置１は以上のような構成を有するので、眼科診断装置１を用いて、図示しない被検眼などにＬＥＤ１１からの光を照射する際には、眼科診断装置１のグリップバー３を片手で保持した状態で、ＬＥＤスイッチ３ａを矢印Ｂ方向に押し込んで、電源部１３に電源を投入する。すると、電池１２からの直流の電源電圧ＶＢが電源部１３を介して調光部１５に入力され、調光部１５は、入力された電源電圧ＶＢから、ＬＥＤ１１をＰＷＭ方式で駆動するためのパルス状に変調されたパルス電圧ＶＰを生成してＬＥＤ駆動部２０に出力する。ＬＥＤ駆動部２０は、変調されたパルス電圧ＶＰによりＬＥＤ１１を駆動し、ＬＥＤ１１は発光駆動され光８を発光する。 Since the ophthalmic diagnosis apparatus 1 has the above-described configuration, when the ophthalmic diagnosis apparatus 1 is used to irradiate light from the LED 11 to an eye to be examined (not shown), the grip bar 3 of the ophthalmologic diagnosis apparatus 1 can be held with one hand. In the held state, the LED switch 3a is pushed in the direction of arrow B to turn on the power supply unit 13. Then, the DC power supply voltage VB from the battery 12 is input to the dimming unit 15 via the power supply unit 13, and the dimming unit 15 uses the pulse for driving the LED 11 in the PWM method from the input power supply voltage VB. The pulse voltage VP modulated in a shape is generated and output to the LED drive unit 20. The LED driving unit 20 drives the LED 11 with the modulated pulse voltage VP, and the LED 11 is driven to emit light to emit light 8.

このパルス電圧ＶＰは、図３に示すように、高電圧部ＶＨと低電圧部ＶＬとに変調された矩形波であり、波長Ｔのうち、高電圧部ＶＨは時間ｔ１であり、低電圧部ＶＬは時間Ｔ−ｔ１である。波長Ｔは適宜設定することが出来るが、例えば、標準で１／９００秒（１．１１msec）程度で有り、その波長Ｔは、調光部１５に接続された波長変更ダイアル１５ａを調整することで適宜な範囲で調整することが出来る。この時、ＬＥＤのパルス電圧ＶＰによる駆動の影響を受けて、電源部１３からの電源電圧ＶＢも変動し、図３に示すように、パルス電圧ＶＰとは逆位相の、高電圧部ＶＢＨと低電圧部ＶＢＬとに変調された矩形波が生成される。 As shown in FIG. 3, the pulse voltage VP is a rectangular wave modulated into a high voltage part VH and a low voltage part VL. Among the wavelengths T, the high voltage part VH is time t1, and the low voltage part VL is time T-t1. The wavelength T can be set as appropriate. For example, the wavelength T is typically about 1/900 seconds (1.11 msec), and the wavelength T is adjusted by adjusting the wavelength changing dial 15a connected to the dimming unit 15. Adjustment can be made within an appropriate range. At this time, the power supply voltage VB from the power supply unit 13 also fluctuates due to the influence of driving by the pulse voltage VP of the LED, and as shown in FIG. A rectangular wave modulated to the voltage unit VBL is generated.

電池１２が消耗していない状態では、電源電圧ＶＢは、図３の実線で示すような電圧ＶＢ１となっており、電圧ＶＢ１は、その供給最低電圧である低電圧部ＶＢＬの電圧が、ＬＥＤ１１の最低駆動電圧値Ｖｆを十分に上回っているので、調光部１５，ＬＥＤ駆動部２０を介してＬＥＤ１１は、所定の波長Ｔで円滑に駆動され、ＬＥＤ照明部１０の照射部１０ａからは適切な光量の光８を外部に照射することが出来る。この際、ＬＥＤ１１は、パルス電圧ＶＰにおける高電圧部ＶＨで駆動されて点灯し、低電圧部ＶＬでは最低駆動電圧値Ｖｆを下回って非駆動状態となって消灯し、全体的には、高電圧部ＶＨに対する低電圧部ＶＬの比（デューティ比）に応じた明るさの光８を外部に発光することが出来る。 In a state where the battery 12 is not consumed, the power supply voltage VB is the voltage VB1 as shown by the solid line in FIG. 3, and the voltage VB1 is the voltage of the low voltage portion VBL, which is the lowest supply voltage, of the LED 11 Since the minimum drive voltage value Vf is sufficiently exceeded, the LED 11 is smoothly driven at the predetermined wavelength T via the light control unit 15 and the LED drive unit 20, and is appropriate from the irradiation unit 10 a of the LED illumination unit 10. It is possible to irradiate the outside with a light amount 8. At this time, the LED 11 is driven by the high voltage portion VH in the pulse voltage VP to be turned on, and the low voltage portion VL is turned off in the non-driving state below the minimum drive voltage value Vf. Light 8 having brightness according to the ratio (duty ratio) of the low voltage part VL to the part VH can be emitted to the outside.

なお、電源投入から、調光部１５が適正に変調されたパルス電圧ＶＰをＬＥＤ駆動部２０に出力するまでには、例えば２０〜３０msec程度の立ち上がり時間を必要とし、当該立ち上がり時間では、電源部１３から供給される直流電圧ＶＢがパルス電圧ＶＰに何ら変調されずにそのままＬＥＤ駆動部２０に出力される。そこで、遅延制御部１９は、例えば電源部１３から出力される電源投入信号をトリガーＴＲとして入力し、ＬＥＤ駆動部２０を電源投入時から所定時間、例えば５０msecの間、ＬＥＤ駆動部２０に対してＬＥＤ１１を駆動しないように駆動禁止信号ＰＲを出力し、ＬＥＤ駆動部２０によるＬＥＤ１１の駆動を禁止する制御を行う。これにより、ＬＥＤ１１は変調されていない直流電圧ＶＢで駆動されることが未然に防止され、直流電圧ＶＢで駆動されたＬＥＤ１１からの強い光８が照射孔１０ａより被検眼などに照射されることが未然に防止される。 Note that a rise time of, for example, about 20 to 30 msec is required from when the power is turned on until the dimming unit 15 outputs the appropriately modulated pulse voltage VP to the LED drive unit 20. The DC voltage VB supplied from 13 is output to the LED drive unit 20 as it is without being modulated by the pulse voltage VP. Therefore, the delay control unit 19 inputs, for example, a power-on signal output from the power supply unit 13 as a trigger TR, and the LED drive unit 20 is supplied to the LED drive unit 20 for a predetermined time, for example, 50 msec from when the power is turned on. A drive prohibition signal PR is output so as not to drive the LED 11, and control for prohibiting the LED drive by the LED drive unit 20 is performed. As a result, the LED 11 is prevented from being driven by the unmodulated DC voltage VB, and the strong light 8 from the LED 11 driven by the DC voltage VB is emitted from the irradiation hole 10a to the eye to be examined. Prevented in advance.

また、出力監視部１６は、電源部１３から出力される電源電圧ＶＢを監視しており、その電圧値、特に低電圧部ＶＢＬの電圧値が出力監視部１６に設定された閾値電圧ＴＨＶを下回っていないかを常時監視している。そして、図３の電源電圧ＶＢ２に示すように、低電圧部ＶＢＬの電圧値が閾値電圧ＴＨＶを下回ったものと判定した場合には、直ちに、電源部１３に対して調光部１５に対するパルス電圧ＶＢの供給を停止するように制御する。すると、調光部１５からのパルス電圧ＶＰのＬＥＤ駆動部２０に対する出力も停止され、ＬＥＤ１１の駆動は停止される。閾値電圧ＴＨＶは、図３に示すように、ＬＥＤ１１の最低駆動電圧値Ｖｆを超える値（例えば、０．２〜０．５Ｖ程度超える電圧値）に設定されているので、電池１２の消耗などにより、電源電圧ＶＢが低下し、ＬＥＤ１１の最低駆動電圧値Ｖｆに近い値にまで低下して（しかし、最低駆動電圧値Ｖｆを超えてはいる）低電圧部ＶＢＬの電圧値が閾値電圧ＴＨＶを下回ると、直ちに電源部１３からの電源電圧ＶＢの調光部１５に対する供給を停止し、ＬＥＤ１１の駆動を停止する。 The output monitoring unit 16 monitors the power supply voltage VB output from the power supply unit 13, and the voltage value, in particular, the voltage value of the low voltage unit VBL falls below the threshold voltage THV set in the output monitoring unit 16. We are constantly monitoring whether or not When it is determined that the voltage value of the low voltage part VBL is lower than the threshold voltage THV, as shown in the power supply voltage VB2 of FIG. Control to stop the supply of VB. Then, the output of the pulse voltage VP from the dimming unit 15 to the LED driving unit 20 is also stopped, and the driving of the LED 11 is stopped. As shown in FIG. 3, the threshold voltage THV is set to a value exceeding the minimum drive voltage value Vf of the LED 11 (for example, a voltage value exceeding about 0.2 to 0.5 V). The power supply voltage VB is reduced to a value close to the minimum drive voltage value Vf of the LED 11 (but exceeds the minimum drive voltage value Vf), and the voltage value of the low voltage portion VBL is lower than the threshold voltage THV. Then, the supply of the power supply voltage VB from the power supply unit 13 to the dimming unit 15 is immediately stopped, and the driving of the LED 11 is stopped.

なお、出力監視部１６は、電源電圧ＶＢ２の低電圧部ＶＢＬの電圧値が閾値電圧ＴＨＶを下回ってＬＥＤ１１の駆動が停止される前に、アラーム部１７を駆動して電池１２が消耗して交換すべきであることを検査者などに告知する。 The output monitoring unit 16 drives the alarm unit 17 to replace the battery 12 when the voltage value of the low voltage unit VBL of the power supply voltage VB2 falls below the threshold voltage THV and stops driving the LED 11. Notify the inspector, etc. that this should be done.

このとき、電源電圧ＶＢ２の最低電圧である低電圧部ＶＢＬの電圧は、ＬＥＤ１１の最低駆動電圧値Ｖｆよりも大きいので、ＬＥＤ１１はフリッカー状態にならずに、直ちに消灯され、電池１２の消耗により、低電圧部ＶＢＬが最低駆動電圧値Ｖｆを下回って、ＬＥＤ１１がフリッカー状態となることを未然に防止することが出来る。この状態で、消耗した電池１２を新しい電池と交換して、再度電源を投入することで、適正な電圧ＶＢ１で、ＬＥＤ１１を駆動することが出来る。 At this time, since the voltage of the low voltage portion VBL, which is the lowest voltage of the power supply voltage VB2, is larger than the lowest drive voltage value Vf of the LED 11, the LED 11 is immediately turned off without being flickered, and the battery 12 is consumed. It can be prevented that the low voltage portion VBL falls below the minimum drive voltage value Vf and the LED 11 enters a flicker state. In this state, by replacing the exhausted battery 12 with a new battery and turning on the power again, the LED 11 can be driven with an appropriate voltage VB1.

なお、光量（明るさ）の変更は、明るさ変更ダイアル３ｂを適宜、図１矢印Ｈ、Ｉ方向に回転することで、調光部１５が図３に示す、パルス電圧ＶＰの低電圧部ＶＬに対する高電圧部ＶＨの波長ｔ１の長さを変化させる（例えば波長ｔ１から波長ｔ１‘へ）。これにより、高電圧部ＶＨに対する低電圧部ＶＬの比、即ちデューティ比が変化するので、ＬＥＤ１１から照射される光８の光量（明るさ）が変化する。 The light amount (brightness) is changed by appropriately rotating the brightness change dial 3b in the directions of arrows H and I in FIG. 1 so that the light control unit 15 has a low voltage part VL of the pulse voltage VP shown in FIG. The length of the wavelength t1 of the high voltage portion VH with respect to is changed (for example, from the wavelength t1 to the wavelength t1 ′). Thereby, since the ratio of the low voltage part VL to the high voltage part VH, that is, the duty ratio changes, the light quantity (brightness) of the light 8 emitted from the LED 11 changes.

なお、既に述べたように、ＬＥＤ１１は高電圧部ＶＨに対応した点灯状態と低電圧部ＶＬに対応した消灯状態を繰り返す形で駆動されるので、その明るさは周期的に変動することとなる。この変動幅は、被検眼に対しては悪影響が生じないように予め設定されているが、眼科診断装置１にカメラ７を装着してカメラ７により動画を撮影する場合には、カメラ７のシャッタースピードとパルス電圧ＶＰの周期の同期が取れていないと、ＬＥＤ１１のカメラ７の取得画像に干渉縞が入ることとなる。そうした場合には、波長変更ダイアル１５ａを操作する。すると、調光部１５は波長変更ダイアル１５ａの操作量に応じて、図３に示すパルス電圧ＶＰの波長Ｔを変更することでパルス電圧ＶＰの周波数を変更してＬＥＤ駆動部２０に出力する。これにより、ＬＥＤ１１から発せられる光８の明暗変動周期は適宜調整されるので、カメラ７のシャッタースピードと同期を取ってカメラ７の取得画像に干渉縞が入らないようにすることが出来る。 As already described, since the LED 11 is driven in such a manner that the lighting state corresponding to the high voltage portion VH and the light-off state corresponding to the low voltage portion VL are repeated, the brightness of the LED 11 fluctuates periodically. . This fluctuation range is set in advance so as not to adversely affect the eye to be examined. However, when the camera 7 is attached to the ophthalmic diagnosis apparatus 1 and a moving image is taken by the camera 7, the shutter of the camera 7 is used. If the speed and the cycle of the pulse voltage VP are not synchronized, interference fringes will appear in the image acquired by the camera 7 of the LED 11. In such a case, the wavelength changing dial 15a is operated. Then, the light control part 15 changes the frequency of the pulse voltage VP by changing the wavelength T of the pulse voltage VP shown in FIG. 3 according to the operation amount of the wavelength change dial 15 a, and outputs it to the LED drive part 20. As a result, the light / dark fluctuation cycle of the light 8 emitted from the LED 11 is adjusted as appropriate, so that interference fringes can be prevented from entering the acquired image of the camera 7 in synchronization with the shutter speed of the camera 7.

なお、波長変更ダイアル１５ａは、一度調整するその後は、カメラ７のシャッタースピードが変更されない限り調整する必要が無いので、眼科診断装置１のベース２の底面など、通常手に触れにくい場所に配置するとよい。 Since the wavelength changing dial 15a does not need to be adjusted unless the shutter speed of the camera 7 is changed after the adjustment, the wavelength changing dial 15a is disposed at a place where it is difficult to touch the hand, such as the bottom surface of the base 2 of the ophthalmologic diagnosis apparatus 1. Good.

１……眼科診断装置
７……カメラ
１１……ＬＥＤ
１２……電池
１５……電圧変調手段（調光部）
１６……電圧監視手段、電圧供給停止手段（出力監視部）
１９……遅延制御手段（遅延制御部）
２０……ＬＥＤ駆動部
Ｔ……波長
ＴＨＶ……閾値電圧
ＶＨ……高電圧部
ＶＬ、ＶＢＬ……低電圧部
Ｖｆ……最低駆動電圧値
ＶＢ，ＶＢ１、ＶＢ２……電源電圧 1 …… Ophthalmological diagnosis device 7 …… Camera 11 …… LED
12 …… Battery 15 …… Voltage modulation means (dimming part)
16: Voltage monitoring means, voltage supply stopping means (output monitoring unit)
19 …… Delay control means (delay control unit)
20 …… LED drive part T …… Wavelength THV …… Threshold voltage VH …… High voltage part VL, VBL …… Low voltage part Vf …… Minimum drive voltage value VB, VB1, VB2 …… Power supply voltage

このＬＥＤに対してＰＷＭ方式による制御を使用すると、ＬＥＤが駆動される（電流がＬＥＤを流れる）影響で電源側の電圧（電源電圧）も、高い電圧（Ｈ）と低い電圧（Ｌ）との間で、ＰＷＭによる駆動電圧とは逆位相のパルス状の電圧変動が生じる。この際、電池が消耗状態になっていると、ＬＥＤがＰＷＭの高い電圧（Ｈ）で点灯されると、逆位相の電源電圧が低い電圧（Ｌ）となり、最低駆動電圧値を下回ってしまい、ＬＥＤが消灯する場合が生じる。ＬＥＤが消灯すると、ＬＥＤを流れる電流が無くなるので、電源側の電圧は高い電圧（Ｈ）に戻り、最低駆動電圧値を上回って、ＬＥＤが再度点灯することとなり、これが繰り返される結果フリッカーが生じて、被検眼に対する悪影響の発生及び想定したＰＷＭ方式による駆動とは異なるサイクルでＬＥＤが駆動されてしまう懸念が生じる。 When the control by the PWM method is used for this LED, the voltage on the power supply side (power supply voltage) is also a high voltage (H) and a low voltage (L) due to the influence of the LED being driven (current flows through the LED). In the meantime, a pulse-like voltage fluctuation having a phase opposite to that of the drive voltage by PWM occurs. At this time, if the battery is exhausted, when the LED is lit at a high PWM voltage (H), the power supply voltage in the opposite phase becomes a low voltage (L), which is lower than the minimum drive voltage value. There is a case where the LED is turned off. When the LED is turned off, the current flowing through the LED disappears, so the voltage on the power supply side returns to a high voltage (H), exceeds the minimum drive voltage value, and the LED is turned on again. As a result, flicker occurs. There is a concern that the adverse effect on the eye to be examined occurs and the LED is driven in a different cycle from the driving by the assumed PWM method.

また、ＰＷＭ方式でＬＥＤを駆動する場合、電源投入時点から、ＰＷＭ用の駆動パルスが生成されるまでの間、パルス変調されていない電池からの直流電圧（電源電圧）が直接ＬＥＤに印加され、ＬＥＤが瞬間的に大光量で発光駆動されてしまい、被検眼に対して悪影響を与える危険性がある。 In addition, when driving an LED by the PWM method, a direct-current voltage (power supply voltage) from a battery that is not pulse-modulated is applied directly to the LED from when the power is turned on until a drive pulse for PWM is generated, There is a risk that the LED is instantaneously driven to emit light with a large amount of light, which adversely affects the eye to be examined.

こうした点を改善するために、電源投入時に、パルス変調前の直流電圧（電源電圧）がＬＥＤに入力しないように、一定の遅延時間（例えば、５０ｍｓｅｃ程度）だけＬＥＤへの駆動電圧の印加を遅らせる遅延回路を設け、ＰＷＭ用の駆動パルスが生成された後に当該駆動パルスでＬＥＤを駆動する方式が提案されている。 In order to improve these points, the application of the drive voltage to the LED is delayed by a certain delay time (for example, about 50 msec) so that the DC voltage (power supply voltage) before pulse modulation is not input to the LED when the power is turned on. There has been proposed a system in which a delay circuit is provided and an LED is driven with the drive pulse after a PWM drive pulse is generated.

１……眼科診断装置
７……カメラ
１１……ＬＥＤ
１２……電池
１５……電圧変調手段（調光部）
１６……電圧監視手段、電圧供給停止手段（出力監視部）
１９……遅延制御手段（遅延制御部）
２０……ＬＥＤ駆動部
Ｔ……波長
ＴＨＶ……閾値電圧
ＶＨ……高電圧部
ＶＬ、ＶＢＬ……低電圧部
Ｖｆ……最低駆動電圧値
ＶＢ，ＶＢ１、ＶＢ２……電源電圧 1 …… Ophthalmological diagnosis device 7 …… Camera 11 …… LED
12 …… Battery 15 …… Voltage modulation means (dimming part)
16: Voltage monitoring means, voltage supply stopping means (output monitoring unit)
19 …… Delay control means (delay control unit)
20 …… LED drive unit T …… Wavelength THV …… Threshold voltage VH …… High voltage unit
VL, VBL: Low voltage Vf: Minimum drive voltage value VB, VB1, VB2: Power supply voltage

Claims

An LED having a minimum driving voltage value, an LED driving unit for driving the LED to emit light, a battery, and a DC power supply voltage from the battery are modulated into a pulse voltage of a predetermined wavelength including a high voltage part and a low voltage part. In the ophthalmologic diagnosis apparatus for driving the LED with the pulse voltage output from the voltage modulation means, the voltage modulation means for outputting to the LED drive section,
A voltage for monitoring whether the voltage value of the low voltage portion of the power supply voltage, which fluctuates due to the influence of driving of the LED driven by the pulse voltage, is below a threshold voltage set to a value exceeding the minimum driving voltage value Monitoring means; and
Voltage supply stopping means for stopping supply of the power supply voltage and stopping driving of the LED when the voltage monitoring means determines that the voltage value of the low voltage portion of the power supply voltage is lower than the threshold voltage. An ophthalmologic diagnosis apparatus characterized by comprising:

2. The ophthalmologic diagnosis apparatus according to claim 1, further comprising delay control means for prohibiting driving of the LED by the LED driving unit for a predetermined time from the time of turning on the power when the power from the battery is turned on.

The ophthalmologic diagnosis apparatus according to claim 1, further comprising a wavelength changing unit capable of changing the wavelength of the pulse voltage output from the voltage modulating unit.

4. The ophthalmologic diagnosis apparatus according to claim 3, wherein the ophthalmologic diagnosis apparatus has a detachable camera capable of recording an image of an eye to be examined as a moving image.