TECHNICAL FIELD The present invention relates to gift artifacts with added electronic effect means.

More particular the invention relates to paper communication means such as gift artifacts, stationery, agendas, paper books and packaging materials that are provided with effect means that create visual effects. BACKGROUND

Communication means such as greeting cards, stationery, agendas, paper books, mugs and packaging materials (hereinafter referred to as "gift artifacts") may be provided with effect means that create light effects which are activated by a manipulation of the user (such as a receiver of the gift artifact). The purpose of these effect means is to evoke a response by the user. A response may comprise attracting attention of the user to a message or graphic art on e.g. a greeting card, or evoke an emotional response, such as surprise by the user after the activation of the card. These effect means are activated when manipulated by a user i.e. a mechanical activation, such as opening the card or pressing an activation button. These effect means usually comprise Light Emitting Diodes (LEDs) which produce light in various colors and brightness.

Considering the limitations in cost price and power consumption, effect means in gift artifacts usually run on battery power, in combination with a configuration wherein the user has to manipulate the gift artifact to activate the effect means. Examples of greeting cards which are provided with surprising light and/or sound effects may be found in patent literature such as described below.

USA patent 4,363,081 by Wilbur discloses mechanical activation by a slide switch which is formed by a pair of conductive foil areas on the printed circuit board and a conductive shorting member is attached to the tab. As the card is opened, the tab translates behind the display panel and the shorting member wipes across the pair of foil areas, to complete the circuit between the battery and lamps, to turn on the LED's. USA patent 8,739,438 B1 discloses a greeting card with LED lights placed behind various die cut shapes which make up the paper scene such that when the lights are illuminated, the paper scene is back-lit. The lights may be programmed with various lighting effects, such as for example blinking (repetitive on/off); twinkling (two or more lights with fast alternating blink); and slow glow (starts as dim light that progressively gets brighter). Different timing patterns may also be used with the various lighting effects. Each light may have the same or different lighting effects. The lights may be turned on or illuminated in a particular sequence or may all be turned on or illuminated at once.

Dutch patent 1029897 by Fun Industries B.V. The light emitting components can be precisely synchronized with the sound being played back. Translucent components in the medium are rendered visible or invisible by this light in order to enhance or support the effect of the sound. The medium includes an integral electronic circuit for playing back sound and operating light emitting components, e.g. LED's.

International patent application WO 2012/093935 A1 by applicant is summarized as a device and method for attracting attention in greeting cards comprising a power supply, effect means arranged for selectively increasing or decreasing visibility of graphical presentations and an electronic circuit arranged for changing the state of effect means to become at least partly transparent in a first state and to be less transparent in a second state than in the first state.

Dutch patent NL1039975 by applicant is summarized as a greeting card with a graphical presentation, a light source and an electronic circuit arranged for switching the light source on/off, wherein a one-way mirror covers the graphical presentation.

A disadvantage of the current art solutions is that the LED behind a displayed image or a window is clearly visible for a user and identifiable as an LED. This devaluate the experience of surprise and wonder and/or fails to provide the impression of a realistic light effect.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide a gift artifact which creates a more surprising and/or realistic light effect while keeping the costs of production of the gift artifact as low as possible. The object is realized by a gift artifact capable of generating a visual effect, the gift artifact comprising a front sheet and a back sheet, together forming a relatively flat housing, the front sheets displaying images and/or information, whereby the housing further comprises a control means arranged for controlling the effect means, an activation means arranged for activating the control means and a power means for supplying electrical power to the various means, wherein the front sheet comprises a translucent effect sheet arranged for covering the housing at least partially, the effect sheet having a front side which is arranged for being visible by a user of the artifact and a back side which is hidden for the user, whereby the effect sheet comprises an effect structure which, when lit from behind by the light source, causes a distorted light effect on the front side.

The invention is summarized in the following clauses.

1. A gift artifact capable of generating a visual effect, the gift artifact comprising a front sheet and a back sheet, together forming a relatively flat housing, the front sheets displaying images and/or information; whereby the housing further comprises:

- a light source;

- a control means arranged for controlling the effect means;

- an activation means arranged for activating the control means;

- a power means for supplying electrical power to the activation means, the control means, and the effect means,

characterized in that, the front sheet comprises a translucent effect sheet arranged for covering the housing at least partially, the effect sheet having a front side which is arranged for being visible by a user of the artifact and a back side which is hidden for the user, whereby the effect sheet comprises an effect structure which, when lit from behind by the light source, causes a distorted light effect on the front side.

2. The gift artifact according to clause 1 , characterized in that the distorted light effect comprises any effect of the effects comprising:

- a sparkling effect;

- a radiant effect;

- a gradient effect;

- a radial effect;

- a star shaped effect; - a diffusion effect;

- a lens flare effect;

- a moire pattern effect;

- a laser light effect;

- a rainbow effect.

3. The gift artifact according to clause 1 or 2, characterized in that the distortion of the distorted light effect is created by a three-dimensional structure comprising any structure of the structures comprising:

- ribs;

- faceted projections;

- polyhedrons, such as pyramids;

- prisms;

- bumps and/or indents.

4. The gift artifact according to any one of the clauses 1-3, characterized in that the light source comprises a concentrated light source.

5. The gift artifact according to clause 4, characterized in that the concentrated light source comprises a LED with a lens arranged for directing light in a viewing angle with a range between 15-90 degrees.

6. The gift artifact according to clause 5, characterized in that viewing angle of the LED is in the range between 25-60 degrees.

7. The gift artifact according to any one of the preceding clauses, characterized in that the effect sheet is arranged for being positioned at a distance from the light source, whereby the distortion is increased proportionally to the increase of said distance. BRIEF DESCRIPTION OF THE DRAWINGS

The figures show views of embodiments in accordance with the present invention. FIGURE 1 shows an example of a gift artifact according to the present invention.

The given example comprises a greeting card in a first position.

FIGURE 2 shows an example of a gift artifact according to the present invention.

The given example comprises a greeting card in a second position. FIGURE 3 Shows an example of an effect sheet according to the present invention, when lit from behind. DETAILED DESCRIPTION

The invention is now described by the following aspects and embodiments, with reference to the figures.

FIGURE 1 shows an example of a gift artifact 100 according to the present invention. The given example comprises a greeting card in a first position, wherein a back sheet 101 , which may comprise a paper sheet, is positioned relatively close to a front sheet 105, which may comprise a paper sheet as well. A light source 102 is placed at the front of back sheet 101. In the example, the light source comprises an LED 102 which is arranged for directing a relatively concentrated beam of light towards the back of front sheet 105. The width of the beam of LED 102 is schematically depicted by dotted line 103a and the area that is most intensively lighted is depicted by dotted line 104a. Front sheet 105 has a die cut 106, which in the depicted example is star shaped. In the open space of die cut 106 a piece of translucent sheet 107 is placed, for example by gluing sheet 107 to the back of front sheet 107 in such a way that it at least partially overlaps die cut 106. Hereinafter sheet 107 is referred to as "effect sheet".

Effect sheet 107 is comprised of a sheet material which is provided with a structure that shatters or distorts light. When sheet 105 is lit by LED 102 from the back, a surprising effect may be witnessed at the front side of sheet 105. Depending on the structure (of which examples are given above) of effect sheet 107, different effects may be realized. In the given example of figure 1 , LED 102 is positioned relatively close to effect sheet 107, which leads to a relatively small concentrated area that is lit. The effect may be that the part of effect sheet 107 which creates the most effect is concentrated within and around area 108a. The figure shows area 108a in a grey star shape. In practice, the effects are too rich in color and shapes for the drawing to show. In general, the sparkling effect may me very exciting for a user to see, whereas the solution is relatively easy and cost-effective to manufacture.

FIGURE 2 shows an example of a gift artifact 100 according to the present invention. The given example comprises a greeting card in a second position, wherein back sheet 101 is placed further apart from front sheet 105, and thus further apart from effect sheet 107, further than in the example of figure 1. The effect is that the beam of light spreads out more (as depicted by dotted line 103b) and therefor the area 104b that is lit, is relatively bigger than area 104a in figure 1. This in turn results in a larger area being affected by the distorted light, which may cause an even greater exciting effect for the user. The distance may vary from close to zero when the card's front 105 sheet is folded towards back sheet 101. Card 100 may be activated by folding front sheet 105 away from back sheet 101 , therefor actuating a control (not shown) and LED 102, until the preferred distance between front sheet 105 and back sheet 101 is reached.

Various effects may be achieved such as lines of lights, simulating laser effects, or a rainbow with many colors spread out. The choice of structure and its effect may be in accordance with the choice of pictures on front sheet 105. A sparkling effect may be preferred when star shapes are covering front sheet 105, whereas a diffusive effect may be preferred for a simulation of a candle flame. In the case of a candle light simulation, the LED may be controlled in a flickering and/or fading manner. Likewise, disco laser, or strobe effects may be achieved by a combination of one or more flickering LEDs and a structure of radial ribs along a picture of a disco ball.

Effect sheet 107 may also comprise more than one types of structure, in order to create multiple effects.

FIGURE 3 shows an example of effect sheet 107 when lit from behind by a LED which directs its light through a lens and therefore focusing the light on effect sheet 107. The LED would preferably be positioned at a distance between 0,5mm and 1 ,5 mm.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that a person skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The term "and/or" includes any and all combinations of one or more of the associated listed items. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The article "the" preceding an element does not exclude the presence of a plurality of such elements. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.