DE3116300C2 - Device for determining color ametropia - Google Patents

Abstract

In a device for the detection of color ametropia of the human eye, which consists of devices for generating individual radiation paths of different colors and controllable intensity and an observation area which is composed of a mixed field and a comparison field, a prism block is provided, which consists of several prisms, which at least partially form deflection or beam splitter cubes. One or more detectors are provided to measure the brightness of the mixed or comparison field and the ratio of the brightnesses of the colors used to generate the mixed field. The useful beam exit surface of the prism block is preferably matted and serves as an observation surface.

Description

* a first beam splitter cube (22), which produces a comparison light measuring beam from the comparison light beam path decoupled,

* a second beam splitter cube (23) through which the comparison light measuring beam hits the detector (24) falls,

* a first deflecting prism (14) for deflecting the comparison light beam path onto the Comparison field,

* a third beam splitter cube (13), which makes the two beam paths to be mixed different Absorbs color and whose first exit surface is directed towards the mixed field, while measuring beams of the mixed light components emerge from its second exit surface,

* A second deflecting prism (40) which is combined with the first deflecting prism (14) to form a cube is and deflects the measuring beams of the mixed light components, and

* A third deflecting prism (25), which is between the second deflecting prism (40) and the second Beam splitter cube (23) is arranged in such a way that the measuring beams of the mixed light components also hit the detector (24) and

that means for sequential pulsing of the light sources (1, 2, 3) and for synchronous switching of the Detector output signal are provided on separate measuring channels.

5. Apparatus according to claim 4, characterized in that the three light sources are replaced by Optical fibers (27,28,29), whose input surfaces too lead a single light source (26), and that a controllable intensity attenuator for each beam path is provided.

6. Device according to one of claims 1 to 5, characterized in that for changing the Color saturation of the comparison field a further beam path (33) with white light is provided, which is reflected in the beam path of the comparison light.

7. Device according to one of claims 1 to 6, characterized in that the detectors opposing prism faces lenses (15) are cemented.

8. Device according to one of claims 1 to 7, characterized in that the Ausnttsflächen (19, 20) of the prism block are frosted and serve as a mixed field and comparison field.

9. Device according to one of claims 1 to 8, characterized in that the beam paths Color filters, in particular interference filters, included.

10. The device according to claim 9, characterized in that that the color filters are replaceable.

The invention relates to a device for determining color ametropia of the human eye according to the preamble of claim 1. Such a device is known from US Pat. No. 3,947,099.

From US-PS 39 47 099 it is also known to illuminate the two color fields to be compared to use light emitting diodes. Such semiconductor light sources can be varied in their luminous intensity electronically control in a simple manner, whereby the brightness adjustment of the two color fields is carried out will. After the device has been calibrated, it can then be used to achieve a certain luminous intensity required current strength of the two mixed light sources (red-green) in comparison to the setting of the yellow light determined the type and extent of color ametropia will.

From DE-AS 26 02 304 a device is also known which is used to generate the comparison light and light-emitting diodes for the mixed red and green light.

Other known devices for testing the human eye for color vision in various ways Color areas are generally built as prism spectral apparatus. The most common device

The anomaloscope according to Nagel, which has been standardized since August 1966, is of this type (DIN 6 160).

A significant simplification of the known measuring principle is that it is based on a precision prism apparatus dispensed with and the presentation of two color fields to be compared through appropriate filter discs is made. This is in a device described in DE-AS 15 66 142 for color matching a filter disc designed as a graduated filter that is moved mechanically in the field of view. Of the Brightness comparison of both color fields should be in this known methods can be achieved by a gray wedge, the position of which is determined by a link plate adapted to the transmission curve of the graduated filter. is controlled.

However, all known methods and devices have the following major disadvantage: The Luminous intensity of the color fields as well as the intensity ratio of the mixed field is determined by a mechanical or electronic influencing of the light source or the light source itself is set and varies in all In cases it must be ensured that there is a clear and unchangeable connection between the Manipulated variable (e.g. split jaw position) and the light intensity in the field of view. By aging Components (especially the light source) and due to thermal influences (a graduation on the mixing screw of the anomaloscope according to Nagel means a mechanical gap displacement by 5 μίτι) this can Lost context. Therefore, in the case of the known anomaloscope arrangements, considerable Requirements are placed on the mechanical precision. In addition, the sources of illumination are more common to change to ensure that a certain color temperature is maintained. this applies even when using light emitting diodes.

The present invention has for its object to develop a device in which between the manipulated variable of the device and the light intensity in the field of view always have a clear relationship exists and a reliable examination of the human eye is possible with little expenditure on equipment is. In addition, the device should have a more compact design and allow abse'uter measurements to be carried out enable.

This object is achieved in a device of the type mentioned by the features of the characterizing Part of claim 1 solved. Advantageous embodiments of the invention are shown in Described sub-tensions.

The main advantage of the device according to the invention is in particular that it is extremely stable and is compact and can be absolutely calibrated. The device can also be designed in such a way that that the examination of the human color vision according to DIN 6 160 can be carried out. With a filter set is the diagnosis of protanopia (red blindness), protanomaly (red weakness), deuteranopia (green blindness) or Deutanomaly (Greenschwäehe) possible, so when a blue-green mixed field and the In addition, the corresponding comparison field is also used for diagnosing the relatively rare ones Tritanopia (blue blindness) and tritanomaly (reduction of blue sensitivity) can be used.

Through the direct measurement of the luminous field density assigned to each individual color channel and through the The device is a stable, immovable structure of the optical means in the form of a firmly cemented prism block extremely insensitive to signs of aging of the light sources or to misalignments as a result of shock, vibration or contamination. By using; a simple microprocessor the anomalous quotient can be calculated from the measured color intensities and displayed will.

In the following, the invention is explained in more detail with the aid of drawings showing only one embodiment explained. the

F i g. 1 to 3 show in schematic simplification three possible embodiments of the anomaloscope according to the invention.

In the embodiment according to FIG. 1, three lamps 1, 2 and 3 are used as light sources, the light of which is collimated by a lens 4, 5 and 6 and spectrally clipped by suitable filters 7, 8 and 9. According to DIN 6, the yellow channel 9 should have a wavelength of 594 μm with a half-width of 10 nm. For the red and green channels 7 and 8, wavelengths of 660 nm with a half-width of 22 nm and 550 nm with a half-width of 9 nm prescribed. These spectral properties can be achieved with commercially available interference filters.

The three beam paths (yellow, green and red) enter a firmly cemented prism block. of different Deflection and beam splitter cubes 10, 11 and 12, a beam splitter cube 13 for mixing the red-green partial beams and a deflection cube 14. All deflection and beam splitter cubes are turned off two prisms formed. The deflection cube 14 consists of two reflection prisms, so that the diagonal The reflection surface acts as a beam deflecting mirror from both sides.

On the dice 10, 11 and 12 a part of the respective Light beam, namely a few percent decoupled and cemented onto the exit surface by means of a solid Plano-convex lens 15 on a detector 16, 17 and 18 collected. One of the receiving surfaces of the detectors 16 and 17 is 90 ° out of the plane of the drawing to think turned out so that these rays do not penetrate each other.

The detectors measure the intensity of the individual partial light beams. They give after appropriate calibration the measure of the luminance of the yellow field and the mixing ratio of the mixed field. as Detectors are expediently used silicon diodes, which in their. · Spectral sensitivity curve can be adapted exactly to the human eye.

The fecal green partial beams are in the prism cube 13 mixed in a ratio of 1: 1. An exit surface 19 of this cube is matted and serves directly as an observation surface. The comparison surface 20 is determined by the exit surface of the deflection cube, which is also matted or Reflexionsprisr.as 14 formed. The reflection surface of this cube directs the yellow beam onto the observation surface 20 and at the same time aligns the coming from the second exit surface of the mixed throw 13 Beam via a cemented converging lens 15 onto the mixed light detector 21. At this detector 21 can the luminance_ 'of the mixed field can be measured directly. If necessary, however, this detector can also be used 21 and the ratio of the brightnesses used to generate the mixed field Colors from those determined by detectors 16 and 17

Values are determined.

The signals from the detectors 16, 17,. 18 and 21 become an electronic signal processing and control circuit fed. This circuit processes the measurement signals and shows the anomalous quotient according to Nagel at. The mean standard equation of the CIE standard observer can be used as a basis for this calculation because the objective luminance determination enables an absolute calibration of the device. In addition, the lamp intensities are regulated in the control circuit, so that in the case of color matching over the entire Mixed area the luminance of the mixed area and comparison area is the same. This brightness control can be switched off if the brightness is to be equalized with a given mixing ratio. is

Another embodiment of the anomaloscope according to the invention is shown in FIG. The production dsr drsi spectral colors are analogous to that in Fig. 1 shown device by using the light sources 1, 2 and 3, each of which has the lenses 4, 5 and 6 and the filters 7, 8 and 9 are assigned. The prism block consists of a beam splitter cube 13 for mixing the red-green partial beams, a deflection cube 14 formed from two reflection prisms and from two further deflection or beam splitter cubes 22 and 23, as well as a reflection prism 25. Zur To measure the light intensities, however, only a single detector 24 is used, which points to all three beam components be directed, namely red-green over deflection cube 13 and reflection prism 25 and yellow over Deflection or beam splitter cubes 22 and 23. The separation of the individual beam components and their selective measurement is achieved in that the light sources 1, 2 and 3 are pulsed sequentially. The ones assigned to each lamp Detector pulses are sent to different signal processing channels switched and further processed separately.

The structure of the prism block in FIG. 3 corresponds to the embodiment shown in FIG. 2 arrangement shown. The difference from that in FIG. In this case, the arrangement shown in FIG. 2 consists in the individual spectral channels being supplied with radiation using only one light source 26 via light-conducting fibers 27, 28 and 29. The radiation source 26 is continuously in operation and cannot be regulated. The luminance of the color fields is varied by inserting optical attenuators 30, 31 and 32 into the individual partial beam paths The measurement and regulation of the light intensity of the partial beams is carried out with a detector 24 as in FIG. 2 or with several detectors as in FIG only so that fast optical switching processes can be implemented.

For the use of the in F i g. 3 for the diagnosis of the tritanomaly must be observed, that the color saturation of the comparison field 20 must be reduced by adding white light, since the mixture of blue and green always results in a color that is closer to the white point of the color triangle lies than the corresponding pure spectral color. A simple way of adding white light to the comparison field, is that an unfiltered light component with the help of a further optical fiber 33 over the anyway existing beam splitter cube 22 is displayed in the beam path of the comparison field. Also the As usual, the beam path of the white light is provided with a lens 34 and an optical attenuator 35. This relatively simple additional equipment of the device offers a considerable extension of the diagnostic possibilities. So the difference sensitivity for saturation differences and the spectral Light sensitivity can be measured. In addition, the white channel can be used to neutralize the subject to be examined Eye can be used. A corresponding measure for this purpose is also necessary in the case of the FIG. 1 and 2 arrangements shown are possible.

For this purpose 2 sheets of drawings

Claims (4)

Patent claims: 1. Device for the detection of color ametropia of the human eye, consisting of from devices for generating individual beam paths of different colors and adjustable Intensity, from optical means for mixing two paths of rays of different colors as well for decoupling, deflecting and dividing the beam paths, from an observation area that consists of a mixed field and a comparison field is composed, and of at least one detector for detecting the luminance, characterized in that the optical means consist of deflecting prisms and There are beam splitter cubes that are combined to form a prism block, that the luminance of each of the beam paths separately is detected and 2ü that the relevant detector output signals on the one hand to determine the degree of color ametropia and, on the other hand, to regulate the Serve luminance within the individual beam paths. 2. Device according to claim 1, characterized in that that three beam paths with three light sources (1,2,3) and three detectors (16,17,18) are provided and that the prism block consists of three beam splitter cubes assigned to the respective detectors (10, 11, 12) to knop out measuring beam paths from the beam paths, a prism (14) for deflecting the comparison light beam the comparison field and another beam splitter cube (! 3) for mixing 7 two beam paths, whose first exit surface is directed towards the mixed field. 3. Device according to claim 2, characterized in that that a fourth detector (21) is provided for measuring the luminance of the mixed light, which comes from the second exit surface of the further beam splitter cube (13) and from one Deflection prism (40) which is combined with the prism for deflecting the comparison light to form a cube is aimed at the fourth detector (21). 4. Apparatus according to claim 1, characterized in that three beam paths with three light sources and a detector are provided, that the prism block is composed of the following parts is: