JP2008188058A5 - - Google Patents

Claims (3)

A test target in which various test targets including a predetermined target for red-green test are formed is arranged by switching to the optical path, and a red filter and a green filter for dividing the presentation screen are arranged by switching to the presentation optical path, In the optotype presenting apparatus that illuminates the red filter and the green filter from behind with an illumination light source, and presents a red-green inspection optotype having an optotype in a red background and a green background,
A white LED is provided as the illumination light source,
As the red filter and the green filter, commercially available ones are used, the thickness of both filters is the same, and the red and green luminous characteristics when the red-green inspection target is presented by the illumination of the white LED An optotype presenting apparatus comprising a filter manufactured by determining the thickness of both filters so that the two are substantially the same. 2. The visual target presenting device according to claim 1, wherein the green filter has a transmittance of approximately 0 in a wavelength region of a wavelength of 450 nm or less and a wavelength of 600 nm or more, a peak wavelength in the vicinity of a wavelength of 520 to 540 nm, and a thickness of 2.5 mm. Using a commercially available green filter with a peak wavelength transmittance of about 20%,
The red filter has a transmittance of almost 0 in the visible region on the shorter wavelength side than the wavelength of 590 nm, and has a transmittance of 80% or more in the visible region on the longer wavelength side with a wavelength of 630 nm or more at a thickness of 3 mm and 50%. Use a commercially available red filter whose transmittance is around the wavelength of 610 nm,
An optotype presenting apparatus characterized in that the thickness of both filters is reduced to 2.2 to 2.4 mm. 2. The visual target presenting device according to claim 1, wherein the green filter has a transmittance of approximately 0 in a wavelength region of a wavelength of 500 nm or less and a wavelength of 600 nm or more, a peak wavelength near a wavelength of 540 to 550 nm, and a thickness of 2.5 mm. Using a commercially available green filter with a peak wavelength transmittance of about 10-15%,
The red filter has a transmittance of almost 0 in the visible region on the shorter wavelength side than the wavelength of 600 nm, has a transmittance of 80% or more in the visible region on the longer wavelength side with a wavelength of 640 nm or more at a thickness of 2.5 mm, and 50 % Using a commercially available red filter having a transmittance of about 620 nm,
An optotype presenting apparatus characterized in that the thickness of both filters is reduced to 2.2 to 2.4 mm.