JPH0620433B2 - Corneal shape measuring device - Google Patents
Corneal shape measuring deviceInfo
- Publication number
- JPH0620433B2 JPH0620433B2 JP61124435A JP12443586A JPH0620433B2 JP H0620433 B2 JPH0620433 B2 JP H0620433B2 JP 61124435 A JP61124435 A JP 61124435A JP 12443586 A JP12443586 A JP 12443586A JP H0620433 B2 JPH0620433 B2 JP H0620433B2
- Authority
- JP
- Japan
- Prior art keywords
- optical system
- corneal shape
- shape measuring
- light receiving
- index
- 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.)
- Expired - Fee Related
Links
Landscapes
- Eye Examination Apparatus (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は、角膜形状測定装置、更に詳しくは、所定指標
を指標光学系を介して角膜に投影し、該指標の角膜反射
像を測定光学系を介して受光部に投影して角膜形状を自
動測定する角膜形状測定装置に関する。TECHNICAL FIELD The present invention relates to a corneal shape measuring apparatus, and more specifically, it projects a predetermined index onto the cornea via an index optical system and measures a corneal reflection image of the index. The present invention relates to a corneal shape measuring device that projects a light onto a light receiving portion via a system to automatically measure a corneal shape.
（従来技術） 被検眼の角膜形状を知ることにより、角膜の曲率半径、
乱視度、及び乱視軸方向を算出することができ、この算
出される角膜の曲率半径、乱視度、及び乱視軸方向の精
度には、角膜形状の測定精度が大きく影響することが知
られている。そのため、角膜形状の測定には高い精度が
要求されており、指標像を上記受光部に大倍率で投影
し、受光部における視標像の受光面積を大きくして視標
像の分解能を高めることが行われている。(Prior Art) By knowing the shape of the cornea of the eye to be examined, the radius of curvature of the cornea,
It is known that the degree of astigmatism and the direction of the astigmatic axis can be calculated, and the accuracy of measurement of the corneal shape greatly affects the calculated accuracy of the radius of curvature of the cornea, the degree of astigmatism, and the direction of the astigmatic axis. . Therefore, high accuracy is required for measuring the shape of the cornea, and the index image is projected on the light receiving unit at a large magnification to increase the light receiving area of the target image in the light receiving unit to improve the resolution of the target image. Is being done.
（発明が解決しようとする問題点） 測定精度を高めた上記角膜形状測定装置においては、投
影倍率を高めたことにより装置が大型化し、かつ製造コ
ストの高い大型の受光部を使用しなければならなかっ
た。(Problems to be Solved by the Invention) In the above corneal shape measuring apparatus with improved measurement accuracy, the apparatus is upsized due to the increased projection magnification, and a large light receiving section which is expensive to manufacture must be used. There wasn't.
本発明は、従来の角膜形状測定装置の上述の問題点に鑑
みなされたものであって、製造コストの安い小型の受光
部を使用し、全体として小型の角膜形状測定装置を提供
することを目的とする。The present invention has been made in view of the above problems of the conventional corneal shape measuring apparatus, and an object of the present invention is to provide a small corneal shape measuring apparatus as a whole by using a small light receiving unit that is inexpensive in manufacturing cost. And
本発明は、さらに、受光部における塵等の弊害を少なく
した角膜形状測定装置を提供することを目的とする。It is another object of the present invention to provide a corneal shape measuring apparatus in which harmful effects such as dust on the light receiving section are reduced.
（発明の構成） 本発明は、上述の目的を達成するため、所定指標を指標
光学系を介して角膜に投影し、該指標の角膜反射像を測
定光学系を介して受光部に投影して角膜形状を自動測定
する角膜形状測定装置において、上記指標光学系と上記
測定光学系からなる投影光路中に、投影光束を拡散する
ための拡散手段を設けたことを特徴として構成される。(Structure of the Invention) In order to achieve the above-mentioned object, the present invention projects a predetermined index on the cornea via an index optical system and projects a corneal reflection image of the index onto a light receiving unit via a measurement optical system. A corneal shape measuring apparatus for automatically measuring a corneal shape is characterized in that a diffusing means for diffusing a projected light beam is provided in a projection optical path formed by the index optical system and the measuring optical system.
（作 用） 上記構成の本発明によれば、視標投影光束が拡散手段に
よって拡散され、受光部に合焦する視標像がぼける。(Operation) According to the present invention having the above configuration, the target projection light flux is diffused by the diffusing means, and the target image focused on the light receiving portion is blurred.
（実施例） 以下、本発明の実施例の角膜形状測定装置を図に基づい
て説明する。角膜形状測定装置は、第１図に示すよう
に、視標光学系１００と、測定光学系１０２とからな
る。視標光学系１００は、リング状光源１、リング状光
源１の前方に配置されたリング状視標２、リング状視標
２の前方に配置されたリング状拡散板３からなり、これ
ら部材はその中心が測定光学系１０２の光軸１０４上に
あるように配置される。視標光学系１００からの光束は
被検眼Ｅの角膜４に投射され、角膜反射像ａ（虚像）を
形成する。(Example) Hereinafter, a corneal shape measuring apparatus according to an example of the present invention will be described with reference to the drawings. As shown in FIG. 1, the corneal shape measuring apparatus includes a target optical system 100 and a measuring optical system 102. The target optical system 100 includes a ring-shaped light source 1, a ring-shaped target 2 arranged in front of the ring-shaped light source 1, and a ring-shaped diffusion plate 3 arranged in front of the ring-shaped target 2. It is arranged so that its center is on the optical axis 104 of the measurement optical system 102. The light flux from the target optical system 100 is projected on the cornea 4 of the eye E to be inspected to form a corneal reflection image a (virtual image).
測定光学系１０２は、コリメータレンズ５、コリメータ
レンズ５の後側焦点位置に配置された絞り板６、前側焦
点位置を絞り板６に配置した結像レンズ７、そしてコリ
メータレンズ５及び結像レンズ７に関し角膜反射像ａと
共役に配置されたＣＣＤエリアセンサー８からなる。The measurement optical system 102 includes a collimator lens 5, a diaphragm plate 6 arranged at a rear focal position of the collimator lens 5, an imaging lens 7 having a front focal position arranged on the diaphragm plate 6, and the collimator lens 5 and the imaging lens 7. The CCD area sensor 8 is arranged so as to be conjugate with the corneal reflection image a.
以上の構成におけるＣＣＤエリアセンサー８上のリング
状視標２の像は、第２図に示すように、横軸に幅、縦軸
に光強度をとると、βで示すようになり、これはリング
状拡散板３がないαで示す場合に比較してピーク値が下
がるが、幅が拡大してＣＣＤエリアセンサー８のより多
くの受光素子によって受光されるようになる。従って、
リング状視標２の像の位置、すなわち幅の中心である光
量重心をより高精度に検出でき、角膜の曲率半径、乱視
度、及び乱視軸方向を正確に算出することができる。The image of the ring-shaped optotype 2 on the CCD area sensor 8 in the above-described configuration becomes as shown by β when the horizontal axis is the width and the vertical axis is the light intensity, as shown in FIG. Although the peak value is lower than that in the case of α without the ring-shaped diffuser plate 3, the width is expanded and light is received by more light receiving elements of the CCD area sensor 8. Therefore,
The position of the image of the ring-shaped optotype 2, that is, the center of the light amount, which is the center of the width, can be detected with higher accuracy, and the radius of curvature of the cornea, the astigmatism, and the astigmatic axis direction can be accurately calculated.
次に、第３図に基づいて、ＣＣＤエリアセンサー８の各
受光素子の検出値から像幅の中心を求める構成及び作用
を説明する。ＣＣＤエリアセンサー８は、Ａ／Ｄ変換器
３０を介して演算制御回路３１に接続される。演算制御
回路３１にはまた、光量データメモリ３２、アドレス番
地データメモリ３３、プログラムメモリ３４、算出デー
タメモリ３５、及び表示器３６が接続される。Next, with reference to FIG. 3, a configuration and an operation for obtaining the center of the image width from the detection value of each light receiving element of the CCD area sensor 8 will be described. The CCD area sensor 8 is connected to the arithmetic control circuit 31 via the A / D converter 30. A light intensity data memory 32, an address data memory 33, a program memory 34, a calculation data memory 35, and a display 36 are also connected to the arithmetic control circuit 31.
この回路において、ＣＣＤエリアセンサー８によって得
られたアナログ信号は、Ａ／Ｄ変換器３０によってデジ
タル信号に変換され、演算制御回路３１の制御のもと
に、プログラムメモリ３４に記録されているプログラム
に従って各受光素子のアドレス番地に対応づけられて、
光量データメモリ３２とアドレス番地データメモリ３３
に記憶される。In this circuit, the analog signal obtained by the CCD area sensor 8 is converted into a digital signal by the A / D converter 30, and under the control of the arithmetic control circuit 31, according to the program recorded in the program memory 34. Corresponding to the address address of each light receiving element,
Light intensity data memory 32 and address address data memory 33
Memorized in.
つぎに、各アドレス番地に対応した光量データと、この
アドレス番地の座標値とを乗算してその総和を求め、こ
れを光量データの総和で除算することにより、光量重心
すなわち像幅の中心を求めることができる。続いて、求
めた複数の像幅の中心値から任意の５点を選び、これら
の値を一般に知られている楕円形状を求める式 ax2＋2bxy＋cy2＋dx＋ey＋１＝０ に代入することにより角膜形状を特定することができ
る。Next, the light amount data corresponding to each address is multiplied by the coordinate value of this address to obtain the total, and this is divided by the total of the light amount data to obtain the light amount centroid, that is, the center of the image width. be able to. Next, select arbitrary 5 points from the obtained center values of the image widths, and assign these values to the commonly known equation for obtaining the elliptical shape ax 2 + 2bxy + cy 2 + dx + ey + 1 = 0 to identify the corneal shape. can do.
上記角膜形状の算出をそれぞれ異なった５点を選んで複
数回行い、得られた角膜形状の値を平均化することによ
り正確な角膜形状の値を求めることができる。このよう
にして求められた角膜形状の値に基づいて公知の方法に
より角膜の曲率半径、乱視度、及び乱視軸方向を算出す
ることができる。The calculation of the corneal shape is performed a plurality of times by selecting five different points, and the obtained values of the corneal shape are averaged to obtain an accurate value of the corneal shape. The radius of curvature of the cornea, the degree of astigmatism, and the astigmatic axis direction can be calculated by a known method based on the value of the corneal shape thus obtained.
上記実施例においては、リング状拡散板３を視標光学系
１００に配置していたが、拡散部材を測定光学系１０２
に配置しても本発明を有効に実施可能である。In the above embodiment, the ring-shaped diffuser plate 3 is arranged in the target optical system 100, but a diffuser member is used as the measurement optical system 102.
The present invention can be effectively carried out even if it is arranged at.
（発明の効果） 本発明によれば、受光部に投影される像の面積が大きく
なり、また、受光部の各受光素子の受光量分布の勾配が
緩くなり、同じ分解能をもつ受光部を使用しても受光量
重心を求める精度が向上する。従って、製造コストの安
い小型の受光部を使用し、全体として小型の角膜形状測
定装置によっても高精度な角膜の曲率半径、乱視度、及
び乱視軸方向を算出することができる。さらに、受光部
に投影される像の面積が大きくなると、受光部の塵等の
影響が小さくなり、この面からも測定精度が向上する。(Effect of the Invention) According to the present invention, the area of the image projected on the light receiving portion becomes large, the gradient of the received light amount distribution of each light receiving element of the light receiving portion becomes gentle, and the light receiving portion having the same resolution is used. Even so, the accuracy of obtaining the center of gravity of the amount of received light is improved. Therefore, it is possible to calculate the radius of curvature of the cornea, the degree of astigmatism, and the direction of the astigmatic axis with high accuracy by using a small light receiving unit that is inexpensive in manufacturing cost and using a small corneal shape measuring apparatus as a whole. Further, when the area of the image projected on the light receiving portion is large, the influence of dust and the like on the light receiving portion is small, and this aspect also improves the measurement accuracy.
第１図は本発明の実施例の角膜形状測定装置の光学図、
第２図はぼけた像の光量分布の説明図、第３図はデータ
処理回路のブロック図である。 １……リング状光源 ２……リング状視標 ３……リング状拡散板 ５……コリメータレンズ ８……ＣＣＤエリアセンサー １００……視標光学系 １０２……測定光学系FIG. 1 is an optical diagram of a corneal shape measuring apparatus according to an embodiment of the present invention,
FIG. 2 is an explanatory diagram of a light amount distribution of a blurred image, and FIG. 3 is a block diagram of a data processing circuit. 1 ... Ring light source 2 ... Ring target 3 ... Ring diffuser 5 ... Collimator lens 8 ... CCD area sensor 100 ... Target optical system 102 ... Measuring optical system
Claims (3)
し、該指標の角膜反射像を測定光学系を介して受光部に
投影して角膜形状を自動測定する角膜形状測定装置にお
いて、 上記指標光学系と上記測定光学系からなる投影光路中
に、投影光束を拡散するための拡散手段を設けたことを
特徴とする角膜形状測定装置。1. A corneal shape measuring apparatus for automatically measuring a corneal shape by projecting a predetermined index on a cornea through an index optical system and projecting a corneal reflection image of the index onto a light receiving portion through a measuring optical system, A cornea shape measuring device characterized in that a diffusing means for diffusing a projected light beam is provided in a projection optical path formed by the index optical system and the measuring optical system.
れたことを特徴とする特許請求の範囲第１項に記載の角
膜形状測定装置。2. The corneal shape measuring apparatus according to claim 1, wherein the diffusing means is provided in the index optical system.
れたことを特徴とする特許請求の範囲第１項に記載の角
膜形状測定装置。3. The corneal shape measuring apparatus according to claim 1, wherein the diffusing means is provided in the measuring optical system.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61124435A JPH0620433B2 (en) | 1986-05-29 | 1986-05-29 | Corneal shape measuring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61124435A JPH0620433B2 (en) | 1986-05-29 | 1986-05-29 | Corneal shape measuring device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62281921A JPS62281921A (en) | 1987-12-07 |
| JPH0620433B2 true JPH0620433B2 (en) | 1994-03-23 |
Family
ID=14885418
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61124435A Expired - Fee Related JPH0620433B2 (en) | 1986-05-29 | 1986-05-29 | Corneal shape measuring device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0620433B2 (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5829446A (en) * | 1981-08-18 | 1983-02-21 | キヤノン株式会社 | Ophthalmic measuring apparatus |
| JPS5873336A (en) * | 1981-10-28 | 1983-05-02 | 株式会社トプコン | Apparatus for measuring curvature |
| JPS5875530A (en) * | 1981-10-28 | 1983-05-07 | 株式会社トプコン | Apparatus for measuring curvature |
| JPS5977828A (en) * | 1982-10-27 | 1984-05-04 | キヤノン株式会社 | Apparatus for measuring shape of cornea |
| JPS61100227A (en) * | 1984-10-23 | 1986-05-19 | キヤノン株式会社 | Ophthalmic measuring apparatus |
-
1986
- 1986-05-29 JP JP61124435A patent/JPH0620433B2/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5829446A (en) * | 1981-08-18 | 1983-02-21 | キヤノン株式会社 | Ophthalmic measuring apparatus |
| JPS5873336A (en) * | 1981-10-28 | 1983-05-02 | 株式会社トプコン | Apparatus for measuring curvature |
| JPS5875530A (en) * | 1981-10-28 | 1983-05-07 | 株式会社トプコン | Apparatus for measuring curvature |
| JPS5977828A (en) * | 1982-10-27 | 1984-05-04 | キヤノン株式会社 | Apparatus for measuring shape of cornea |
| JPS61100227A (en) * | 1984-10-23 | 1986-05-19 | キヤノン株式会社 | Ophthalmic measuring apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62281921A (en) | 1987-12-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |