Abstract: A keyboard device for a keyboard instrument, which is capable of obtaining stable let-off feeling from across the whole keyboard device. A let-off member is removably mounted on each of adjacent two of ribs of a keyboard chassis. On a first arm disposed between the two ribs, there are provided a first engagement portion that is temporarily engaged with an engagement protrusion of one of the two let-off members mounted on the adjacent two ribs upon depression of a key to thereby add let-off feeling to touch feeling of the key having been depressed, and a second engagement portion that is engaged with a guide portion of the other let-off member such that the second engagement portion is brought into sliding contact with the guide portion, thereby being guided in a vertical direction.

Abstract: A keyboard device for a keyboard instrument includes a keyboard chassis made of synthetic resin and having a stopper support portion for supporting a stopper extending in a left-right direction. Keys extend in a front-rear direction, and each key is pivotally moved downward by depression thereof and pivotally moves upward by release thereof to move into contact with the stopper from below via a contact portion thereof protruding forward, thereby having further upward pivotal movement thereof blocked. The stopper support portion includes a plate-like erected portion extending in the left-right direction along the entirety of the keys, and a stopper mounting portion having the stopper mounted on a lower surface thereof. The keyboard chassis further includes plate-like ribs erected on a front surface of the erected portion such that the ribs are associated with corresponding ones of the contact portions of the keys, respectively.

Abstract: A keyboard device for a keyboard includes a hammer vertically pivotally moved in a manner interlocked with a key having been depressed, and a cushion provided below the hammer, the hammer contacting the cushion from above when the hammer having been pivotally moved upward in accordance with depression of the key returns to an original position in accordance with release of the key. The hammer includes a plurality of protrusions formed at respective spaced location in a rearward sequence from a hammer support shaft, such that they each extend downward. The cushion is formed by a plurality of cushions sequentially contacted by the plurality of protrusions, when the hammer contacts the cushion from above, in order from a protrusion closest to the hammer support shaft toward a protrusion remotest from the hammer support shaft.

Abstract: A light source apparatus according to an aspect of the present disclosure includes an excitation light source that outputs excitation light, a ceramic phosphor that has a first surface and a second surface, converts in terms of wavelength part of the excitation light outputted from the excitation light source and incident via the first surface to generate fluorescence, and causes the fluorescence to exit via the second surface, and a substrate that supports the first surface of the ceramic phosphor. The excitation light outputted from the excitation light source is incident on an exposed portion of the first surface of the ceramic phosphor that is the portion exposed via the substrate. The distance in the exposed portion from an irradiated region irradiated with the excitation light to the substrate is 0.34 mm or greater.

Abstract: A wavelength conversion apparatus according to an aspect of the present disclosure includes a wavelength conversion layer that has a phosphor phase and a matrix phase, the latter of which contains magnesium oxide, and converts excitation light in terms of wavelength and a hydration suppression layer that is provided at least at one of a first surface of the wavelength conversion layer and a second surface on the side opposite from the first surface and suppresses hydration of the magnesium oxide.

Abstract: A light source apparatus according to an aspect of the present disclosure includes an excitation light source that outputs excitation light, a ceramic phosphor that has a first surface and a second surface, converts in terms of wavelength part of the excitation light outputted from the excitation light source and incident via the first surface to generate fluorescence, and causes the fluorescence to exit via the second surface, and a substrate that supports the first surface of the ceramic phosphor. The excitation light outputted from the excitation light source is incident on an exposed portion of the first surface of the ceramic phosphor that is the portion exposed via the substrate. The distance in the exposed portion from an irradiated region irradiated with the excitation light to the substrate is 0.34 mm or greater.

Abstract: A ceramic composite according to the present disclosure has a phosphor phase containing an activator and a phosphor and a matrix phase containing MgO as a light transmissive ceramic material. The ceramic composite is made of an inorganic material, and the content of the phosphor phase is so set that the volume ratio of the phosphor phase to the entire phase including the matrix phase and the phosphor phase is lower than or equal to 20 vol %.

Abstract: A ceramic composite according to the present disclosure has a phosphor phase containing an activator and a phosphor and a matrix phase containing MgO as a light transmissive ceramic material. The ceramic composite is made of an inorganic material, and the content of the phosphor phase is so set that the volume ratio of the phosphor phase to the entire phase including the matrix phase and the phosphor phase is lower than or equal to 20 vol %.

Abstract: A wavelength conversion element includes a substrate having a first surface, a first phosphor layer that has a first excitation light incident surface on which excitation light having a first wavelength is incident, is so provided as to face the first surface, a second phosphor layer that is so provided as to be in contact with part of the first excitation light incident surface, and a reflection layer that is provided between the first phosphor layer and the substrate. The first phosphor layer has an annular shape. The area of the second phosphor layer viewed in the direction in which the excitation light is incident is smaller than the area of the first phosphor layer viewed in the direction in which the excitation light is incident. The thickness of the second phosphor layer is smaller than the thickness of the first phosphor layer.

Abstract: A light source apparatus according to an aspect of the invention includes an excitation light source that emits excitation light, a wavelength conversion layer on which the excitation light is incident and which converts the wavelength of the excitation light to emit fluorescence, a plurality of traveling direction changers that are formed in the wavelength conversion layer and change the traveling direction of the fluorescence, and a substrate on which the wavelength conversion layer is provided. The substrate is rotated around an axis of rotation to change the position on which the excitation light is incident on the wavelength conversion layer over time, and the interval between the plurality of traveling direction changers is smaller than the size of the region on which the excitation light is incident.

Abstract: A light source apparatus according to an aspect of the invention includes an excitation light source that emits excitation light, a wavelength conversion layer on which the excitation light is incident and which converts the wavelength of the excitation light to emit fluorescence, a plurality of traveling direction changers that are formed in the wavelength conversion layer and change the traveling direction of the fluorescence, and a substrate on which the wavelength conversion layer is provided. The substrate is rotated around an axis of rotation to change the position on which the excitation light is incident on the wavelength conversion layer over time, and the interval between the plurality of traveling direction changers is smaller than the size of the region on which the excitation light is incident.

Abstract: A wavelength conversion element includes a substrate having a first surface, a first phosphor layer that has a first excitation light incident surface on which excitation light having a first wavelength is incident, is so provided as to face the first surface, a second phosphor layer that is so provided as to be in contact with part of the first excitation light incident surface, and a reflection layer that is provided between the first phosphor layer and the substrate. The first phosphor layer has an annular shape. The area of the second phosphor layer viewed in the direction in which the excitation light is incident is smaller than the area of the first phosphor layer viewed in the direction in which the excitation light is incident. The thickness of the second phosphor layer is smaller than the thickness of the first phosphor layer.

Abstract: A discharge lamp driver includes a discharge lamp drive unit, a control unit, and a voltage detection part. When an inter-electrode voltage is smaller than a first predetermined value, the control unit controls the discharge lamp drive unit to provide a mixed period in which a first period and a second period are alternately repeated and a third period alternately including a first direct-current period and a second direct-current period. A length of the first direct-current period is larger than a length of the second direct-current period. The length of the second direct-current period is smaller than 0.5 ms. A total of the lengths of the first direct-current periods in the third period is larger than a length of the second period. When the inter-electrode voltage is smaller than the first predetermined value, the control unit is configured to increase the length of the third period in a stepwise manner.

Abstract: A projector according to an aspect of the invention includes a discharge lamp having a light emitting tube and configured to emit light, a light modulation device configured to modulate the light emitted from the discharge lamp in accordance with an image signal, a projection optical system configured to project the light modulated by the light modulation device, a first detection section configured to detect ultraviolet light out of the light emitted from the discharge lamp, and a control section configured to determine a deterioration state of the light emitting tube based on a light intensity of the ultraviolet light detected by the first detection section.

Abstract: A discharge lamp driver includes a discharge lamp drive unit, a control unit, and a voltage detection part. When an inter-electrode voltage is smaller than a first predetermined value, the control unit controls the discharge lamp drive unit to provide a mixed period in which a first period and a second period are alternately repeated and a third period alternately including a first direct-current period and a second direct-current period. A length of the first direct-current period is larger than a length of the second direct-current period. The length of the second direct-current period is smaller than 0.5 ms. A total of the lengths of the first direct-current periods in the third period is larger than a length of the second period. When the inter-electrode voltage is smaller than the first predetermined value, the control unit is configured to increase the length of the third period in a stepwise manner.

Abstract: In a discharge lamp driving device, a mixed period is provided, in which a first period in which an alternating current is supplied and a second period in which a direct current is supplied are alternately repeated and a third period alternately including a first direct current period and a second direct current period in which a direct current having a polarity opposite to a polarity of the direct current in the first direct current period is supplied. Length of the second direct current period is smaller than 0.5 ms. A total of lengths of the first direct current periods in the third period is larger than length of the second period. The third period is not provided at least when the inter-electrode voltage is smaller than a first predetermined value or when a cumulative lighting time of the discharge lamp is smaller than a second predetermined value.

Abstract: A discharge lamp driving device according to one aspect of the invention includes a discharge lamp driving section configured to supply a driving current to a discharge lamp including electrodes and a control section configured to control the discharge lamp driving section. The control section controls the discharge lamp driving section such that a mixed period is provided in which a first period in which an alternating current having a first frequency is supplied to the discharge lamp and a second period in which a direct current is supplied to the discharge lamp are alternately repeated. The first frequency includes a plurality of frequencies different from one another. The control section temporally changes the length of the first period.

Abstract: A discharge lamp driving device includes a discharge lamp driving unit configured to supply a driving current to a discharge lamp including electrodes, a controller configured to control the discharge lamp driving unit, and a voltage detection unit configured to detect an inter-electrode voltage of the discharge lamp, in which the controller controls the discharge lamp driving unit so that the driving current includes a hybrid period in which a first period for supplying an AC current with a first frequency to the discharge lamp and a second period for supplying a DC current to the discharge lamp are alternately repeated, in which the first frequency includes a plurality of different frequencies, and in which the controller changes the first frequency on the basis of at least one of the detected inter-electrode voltage and driving power supplied to the discharge lamp.

Abstract: In a discharge lamp driving device, a mixed period is provided, in which a first period in which an alternating current is supplied and a second period in which a direct current is supplied are alternately repeated and a third period alternately including a first direct current period and a second direct current period in which a direct current having a polarity opposite to a polarity of the direct current in the first direct current period is supplied. Length of the second direct current period is smaller than 0.5 ms. A total of lengths of the first direct current periods in the third period is larger than length of the second period. The third period is not provided at least when the inter-electrode voltage is smaller than a first predetermined value or when a cumulative lighting time of the discharge lamp is smaller than a second predetermined value.

Abstract: In at least one embodiment, a light source apparatus includes a discharge lamp with a pair of electrodes and a driving unit that supplies a driving current to the pair of electrodes. The driving unit includes an AC supplier that supplies an alternating current to the pair of electrodes and a DC supplier that supplies a direct current to the pair of electrodes. The AC supplier is configured to alternately repeat an AC supply section in which the alternating current is supplied and an AC stop section in which the supply of the alternating current is stopped. The DC supplier is configured to supply the direct current during a period corresponding to the AC stop section. A frequency of the direct current is not lower than 10 Hz and not higher than 1 kHz.