Business hours | 9:00 - 17:00


Mail Form

Frequently Asked Questions

  • Q:  What are the differences between phosphorescent materials, fluorescent materials and reflective materials?
    Phospho-rescent materials Quality The materials become self-luminous to glow in darkness by emitting light energy accumulated in the daytime or under light.

    Although the emission is not so strong and the visibility decreases with time, such visibility can last for a certain period of time and can work as marks.

    Fluores-cent materials Quality

    The materials look vibrantly in the areas under light by reacting to such light.


    Although there is no visibility in darkness, the materials, whose color is vibrant and outstanding, can be effectively used for display in daytime or under light.

    Reflective materials Quality

    The materials can look shining by reflecting the light received when seeing them from the light source in darkness.


    Light source is required to see them in darkness. However, by receiving light, the materials can be quite noticeable even from afar, and the visibility in environment where light is being used is quite good.

  • Q: Will the function be lost by ultraviolet rays?

    Materials are inorganic and semi-permanent, and are not deteriorated by ultraviolet rays, etc. No big changes were detected under the xenon arc lamp test (an accelerated weathering test) for 2,030 hours (equivalent to 5 years) in our phosphorescent sheet. However, as organic materials are mixed with them upon being produced as products, actual weather resistance will become shorter, so, when the phosphorescent sheet is  installed, the surface and the edge protection is necessary.

    * This test result was a measured value and not the guaranteed one.

  • Q: How much bright is the phosphorescent visibility?

    There are four units (total luminous flux, illuminance, light intensity, and luminosity) to measure brightness. The brightness of phosphorescent products is represented by the “Luminosity”, and the intensity of light that illuminates the products by the “Illuminance”.

    • Luminosity:Value that represents “how much a light source looks bright”. Amount of light being emitted from a measuring surface. [milli-candela(mcd/㎡)]
    • Illuminance: Brightness of a surface that is illuminated by a light source. Amount of light being irradiated to a measuring surface. [lux(lx)]

    Indication on luminosity and human visual recognition



    Human visual recognition in darkness



    200 or more The level you can read letters. -


    5 or more You can read letters somehow. 10 people


    3 or less You can recognize the outline of objects. 10 people


    2 or less Becoming vague, but you can recognize the objects somehow. 10 people


    1 or less You can hardly recognize the objects. 3 people

    7 people

    0.3 The limit that men’s eyes can recognize (*) -


    *DIN67510: Deutsche Industrie Normen (Long persistence pigments and product)

    Although “brightness” and “darkness” are the matter of sense and there are individual differences, it is thought that, in fact, the illuminance that you can visually confirm in total darkness is about 3mcd/㎡ or more.

    Indication of Illuminance by location (Excerpt from JIS Z9110)

    Location Illuminance
    Sunny / daytime / sunlight 100,000
    Cloudy / daytime / sunlight 32,000
    Rainy / daytime / sunlight 15,000
    At the time of sunrise and sunset 300
    Candle (distance 10cm) *1 200
    Candle (distance 30cm) *1 15
    Under a streetlight of height 5m (single fluorescent lamp) *2 10
    Under moonlight at a full moon 0.24
    Under star light without moon *3 0.001


    Convenience store 1,500
    Studio of television broadcast 1,000
    Brightness on a desk when you study 500-750
    Office (fluorescent lighting) 400-500
    Indoor fire escape, warehouse, living room 30-75
    Bedroom 10-30
    During break in a cinema theater 10-20
    Seats during a movie in a cinema theater 1-2

    *1 Diameter 20mm, core diameter 2.2mm, minor axis of flame size 15mm, major axis 30mm
    *2 Height of an adult face (8lx at the height of 1m, 5lx at the ground)
    *3 Equivalent to the distance of about 3 to 4m from a candle whose diameter and core diameter    are 20mm and 2mm respectively.

    The brightness of lx and cd cannot be compared relatively, but, as a matter of calculation, the brightness that is illuminated by the light source of 1,000mcd (1 candela) at a distance of 1m is set to 1 lux (Illuminance = light intensity (cd) / square of the distance).  

  • Q: How long do the phosphorescent products require to absorb light for phosphorescence?

    Afterglow luminosity of phosphorescent products becomes longer generally with higher illuminance of excitation and longer irradiation time. There, however, is saturation time correlated to irradiation time by respective illuminance, at which point the luminosity will not become higher any more even if the irradiation time is extended longer. (*)

    *The luminosity (initial and afterglow) of phosphorescent products varies depending on the difference of emitting color, particle diameter or paint film thickness of materials, etc

  • Q:  How much energy do the phosphorescent products require

    It is important how much the phosphorescent material can absorb the light energy emitted from the light source.
    Light energy is determined by wavelength and is classified as shown in figure 1.

    Figure 1 - Wavelength classification

    Figure 1 - Wavelength classification

    It is generally recognized that "phosphorescent materials absorb ultraviolet rays and luminous." because the phosphorescent material absorbs wavelengths of 250 to 480 nm, which occupies most of the wavelength of ultraviolet rays. (See figure 2.)

    Figure 2 - Excitation and emission spectra

    Figure 2 - Excitation and emission spectra

    However, since it also absorbs visible light wavelengths of 380 to 480 nm, white LEDs with sharp peaks in the wavelength range of 460 to 470 nm are also effective.

    In the case of outdoors, sunlight is the light source, so the conditions for absorbing light energy are in place. (Sunlight has a wide wavelength range of 300 to 3,000 nm, and the intensity of 400 to 700 nm is particularly strong.)

  • Q:  How long can the phosphorescent products continue emitting light?

    Our phosphorescent products (*1) are fully compliant with the afterglow luminance specified in ISO 22578 and DIN 67510-4. Measured values according to ISO 22578 and DIN 67510 are shown in Table 1.

    Table 1 - Afterglow luminance data

    Our products

    Luminance(mcd/㎡) after a decay time of

    2 10 20 30 60 120 720
    Aluminum phosphorescent sign (*1) - - 698 - 231 108 15
    phosphorescent sheet
    (Ultra-high) (*2)
    - - 402 - 117 52 6
    phosphorescent sheet
    (Ultra-high) (*3)
    2,960 660 - 210 94 - -

    (*1) Aluminum Phosphorescent Sign, Aluminum Phosphorescent Non-slip, Phosphorescent Road Studs, Phosphorescent Sheet, Reflective Luminous Sheet
    (*2) Measurement of afterglow luminescence according to ISO 22578:2021 and JIS Z 9098:2016
    (*3) Measurement of afterglow luminescence according to DIN 67510-4:2008-02

    Table1 means that the product has an afterglow time of more than 12 hours in the dark. Therefore, it is very effective when used as a landmark in places where there are no lighting fixtures such as streetlights. (Our estimate is that our products can be installed and maintained at less than a quarter of the cost of LED solar lighting lamps.)

  • Q: Please explain the International standard for safety signs.

    The ISO standards are shown in Table 1.

    Table 1 - ISO standard




    3864 - 1 : 2011 Graphical symbols - Safety colours and safety signs - Part 1: Design principles for safety signs and safety markings JIS Z 9101
    3864 - 2 : 2016 Graphical symbols - Safety colours and safety signs - Part 2: Design principles for product safety labels JIS S 0101
    3864 - 3 : 2012 Graphical symbols - Safety colours and safety signs - Part 3: Design principles for graphical symbols for use in safety signs Non
    3864 - 4 : 2011 Graphical symbols - Safety colours and safety signs - Part 4: Colorimetric and photometric properties of safety sign materials JIS Z 9103
    7010 : 2012 Graphical symbols - Safety colours and safety signs - Registered safety signs JIS Z 8210
    16069 : 2004 Graphical symbols - Safety signs - Safety way guidance systems (SWGS) JIS Z 9095
    17398 : 2004 Safety colours and safety signs - Classification, performance and durability of safety signs JIS Z 9107
    22578 : 2021 Graphical symbols - Safety colours and safety signs - Natural disaster safety way guidance system JIS Z 9098

    The JIS are shown in Table 2.

    Table 2 - JIS




    Z 9095 : 2011 Graphical symbols -Safety signs - Safety way guidance systems (SWGS) - Phosphorescence type It is a standard for evacuation guidance system for phosphorescent safety signs when evacuating from a building to the outdoors.
    Z 9096 : 2012 Safety sign and guidance line of phosphorescent type on floor It is a standard for installing phosphorescent safety signs and guidance lines on the floor.
    Z 9097 : 2014 Tsunami evacuation guidance - Safety signing system It is a standard that safely guides people to evacuation sites when a tsunami occurs.
    Z 9098 : 2016 Hazard specific evacuation guidance sign system It is a standard that guides people to evacuate safely to evacuation sites with signs when a natural disaster occurs.
    Z 9107 : 1998 Safety sign board It is a standard for the performance and test methods of general safety sign boards, fluorescent safety sign boards,and phosphorescent safety sign boards.
    Z 9107 : 2008 Safety colors and Safety signs - Classification, Performance and durability of Safety signs The title of the standard has been adjusted to ISO 17398.

    The DIN are shown in Table 3.

    Table 3 - DIN



    67510 - 1 : 2020 Phosphorescent pigments and products - Measurement and marking at the producer
    67510 - 4 : 2008 Phosphorescent pigments and products - Products for phosphorescent escape route systems - Markings and applications

    Standards and Regulations we MEET:

    International Standard Organization (ISO)

    Registration, Evaluation, Authorization and Restriction of Chemicals (REACH)

    Deutsche Industrie Normen (DIN)

    Japanese Industrial Standards (JIS)

    ASTM International (ASTM)

    JIS Z 9098:2016
    Hazard specific evacuation guidance sign system

    Japanese Industrial Standards (JIS) are the standards used for industrial activities in Japan. JIS Z9098 stipulates a disaster - type evacuation guidance sign system used when evacuating to a safe place in preparation for disasters such as tsunamis, floods, landslides, and large - scale disasters.
    This standard stipulates the lower limit luminance of the phosphorescent material used for disaster type evacuation guidance signs as a measure against darkness at night or when power is lost.

    The minimum requirement for the luminance decay properties of phosphorescent materials used in components of the Hazard specific evacuation guidance sign system shall be as given in Table 4 for the category of luminance classification.

    Table 4 - Luminance decay classification of outdoor phosphorescent safety signs


    Minimum luminance at 720 min decay time mcd/㎡


    Luminance test of the phosphorescent disaster type evacuation guidance sign uses a xenon lamp, irradiates with ultraviolet intensity (measurement wavelength range 360 to 400 nm) 400 μW for 60 minutes, blocks the light, and measures the value 720 minutes later.


    JIS Z 9107:2008
    Safety colors and Safety signs - Classification, Performance and durability of Safety signs

    This standard is a Japanese Industrial Standard created based on ISO 17398:2004 by changing the technical contents in consideration of the actual situation in Japan. Defined the performance standards related to safety signboards having a phosphorescent performance. Based on the classification method related to various conditions such as the color material of the safety sign, expected usage environment, main structural materials, lighting method, mounting method, gloss, etc., the performance standards and test methods required for each are stipulated.

    The minimum phosphorescence luminance shall fall into one of the four Classifications shown in Table 5.

    Table 5 - Minimum phosphorescence luminance of phosphorescent material using fluorescent lamp


    Minimum luminance(mcd/㎡) after a decay time of

    2 min 10 min 20 min 30 min 60 min
    JA 210 50 24 15 7
    JB 440 105 50 31 15
    JC 880 210 100 62 30
    JD 1,760 420 200 124 60

    Conditions of excitation luminosity: Irradiate fluorescent lamp 200 lux for 20 minutes.

    DIN 67510 Part4:2008
    Phosphorescent pigments and products - Products for phosphorescent escape route systems - Markings and applications

    The DIN standard is a national standard of the Federal Republic of Germany created by the German standard (Deutsches Institut für Normung). This standard specifies the requirements and test methods for phosphorescent products. The categories of luminance decay classification are shown in the table 6.

    It makes specifications for designing phosphorescent products which can be selected and used for specific excitation lighting. In addition to the tests of phosphorescent properties in DIN 67510-1 and DIN 67510-2, it defines mandatory and optional loading tests for durability, along with the associated test conditions. The products defined in this standard are used in escape route systems or in individual applications.
    The geometric shapes and the symbols contained in them are specified in standards such as DIN 4844-2, DIN 4844-3 and BGV A 8.
    This standard does not apply to products which contain radio additives or phosphorus.

    Table 6 - Minimum phosphorescence luminance of phosphorescent material using Xenon lamp


    Minimum luminance(mcd/㎡) after a decay time of

    2 min 10 min 30 min 60 min
    A 108 23 7 3
    B 210 50 15 7
    C 690 140 45 20
    D 1,100 260 85 35
    E 2,200 520 170 70

    Conditions of excitation luminosity: Xenon lamp 1,000 lux for 5 minutes.